Lipids as a source of flavor

Lipids as a Source of Flavor

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Lipids as a Source of Flavor Michael K . Supran,

EDITOR

Thomas J. Lipton, Inc.

A symposiu Flavor Sub-Division of the Division of Agricultural and Food Chemistry at the 174th Meeting of the American Chemical Society, Chicago, Illinois, August 30-31,

1977.

ACS SYMPOSIUM SERIES 75

AMERICAN WASHINGTON,

CHEMICAL D. C.

SOCIETY 1978

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Library of Congress CIP Data Main entry under title: Lipids as a source of flavor. (ACS symposium series; 75 ISSN 0097-6156) Includes bibliographies and index. 1. Lipids—Congresses. 2. Flavor—Congresses. I. Supran, Michael K . , 1939. II. American Chemical Society. Division of Agricultural and Food Chemistry. Flavor Subdivision. III. Series: American Chemical Society. ACS symposium series; 75. QC305.F2L46 ISBN 0-8412-0418-7

664'.06 ASCMC8

78-9739 75 1-121 1978

Copyright © 1978 American Chemical Society A l l Rights Reserved. The appearance of the code at the bottom of the first page of each article in this volume indicates the copyright owner's consent that reprographic copies of the article may be made for personal or internal use or for the personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per copy fee through the Copyright Clearance Center, Inc. for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to copying or transmission by any means—graphic or electronic—for any other purpose, such as for general distribution, for advertising or promotional purposes, for creating new collective works, for resale, or for information storage and retrieval systems. The citation of trade names and/or names of manufacturers in this publication is not to be construed as an endorsement or as approval by A C S of the commercial products or services referenced herein; nor should the mere reference herein to any drawing, specification, chemical process, or other data be regarded as a license or as a conveyance of any right or permission, to the holder, reader, or any other person or corporation, to manufacture, reproduce, use, or sell any patented invention or copyrighted work that may in any way be related thereto. PRINTED IN T H E UNITED STATES OF AMERICAN

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

ACS Symposium Series Robert F . G o u l d , Editor

Advisory Board Kenneth B. Bischoff

Nina I. McClelland

Donald G . Crosby

John B. Pfeiffer

Jeremiah P. Freeman

Joseph V . Rodricks

E. Desmond Goddard

F. Sherwood Rowland

Jack Halpern

Alan C. Sartorelli

Robert A . Hofstader

Raymond B. Seymour

James P. Lodge

Roy L. Whistler

John L. Margrave

Aaron Wold

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

FOREWORD The ACS S Y M P O S I U a medium for publishing symposia quickly in book form. The format of the SERIES parallels that of the continuing A D V A N C E S I N C H E M I S T R Y SERIES except that in order to save time the papers are not typeset but are reproduced as they are submitted by the authors in camera-ready form. As a further means of saving time, the papers are not edited or reviewed except by the symposium chairman, who becomes editor of the book. Papers published in the ACS S Y M P O S I U M SERIES are original contributions not published elsewhere in whole or major part and include reports of research as well as reviews since symposia may embrace both types of presentation.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

PREFACE Τ η organizing this symposium, I had the opportunity and the pleasure of enlisting some of the most eminent researchers in the field of lipid chemistry. Our objective was to review available information and to highlight current research in the field of "Lipids as a Source of Flavor." As a product developer, I have a keen appreciation for the impor­ tance of our topic. In my experience, it is rare that a food product's quality, in a positive or negative sense, can be divorced from considera­ tion of our subject. I believe that attendees to this symposium found the program to be highly informative. I sincerely hope that the reader also will find it so, and therefore will join me in thanking both the authors for their research endeavors and the speakers for their expert presentations. Thomas J. Lipton, Inc. Englewood Cliffs, New Jersey March, 1978

MICHAEL

K.

SUPRAN

ix In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1 The Role Lipids Play in the Positive and Negative Flavors of Foods IRA LITMAN and SCHELLY NUMRYCH Stepan Chemical Company, Flavor/Fragrance Division, 500 Academy Drive, Northbrook, IL 60062 As members of a long had a special interes derived from l i p i d s , for lipids are generally associated with flavor defects in foods. It w i l l not be a surprise to many of you to learn that lipids are also the source of many of nature's finest flavor creations. Lipids, proteins, and carbohydrates, the chief structural components of living cells are also the major sources of flavor in foods. Of the three, lipids may be the most important for the following reasons: 1) They are precursors for many flavorful compounds, with representatives in the aliphatic aldehyde, ketone, lactone, fatty acid, alcohol and ester groups. 2) The intact glyceride tends to modify the flavor of fat soluble compounds by restraining their escape into the air space above. 3) They may also interfere with gustatory ingredients such as salts, sweetening agents, bitterants and acidulants from reaching saliva, a prerequesite for the sense of taste to occur. 4) As a cooking medium, triglycerides produce in foods special flavor effects as a result of, for example, deep fat frying. Their role here is to transfer heat and flavor to the cooking product. 5) It is frequently overlooked that lipids provide a range of polar and non-polar food grade solvents that are used by the food industry. From this range of solvents, one can select a suitable carrier for most any volatile material. Among these solvents are glycerol, mono- and diglycerides, triacetin, tributyrin and vegetable o i l s . 6) It is also important to note that glycerides, which act as reservoirs of volatile flavor, are themselves non-volatile and in this form they contribute to flavor largely through mouth stimulation. For example, they 0-8412-0418-7/78/47-075-001$05.00/0 © 1978 American Chemical Society In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

2

LIPIDS AS A SOURCE O F FLAVOR

impart to melting butter a c h a r a c t e r i s t i c "cooling" e f f e c t . When emulsified i n milk, they impart a r i c h ness that i s sorely missed i n the f l a v o r of skim milk. In i c e cream, the s o l i d i f i e d f a t globules give the product i t s c h a r a c t e r i s t i c "creamy-dryness" associated with good q u a l i t y . Generally, the negative q u a l i t i e s i n food f l a v o r are associated more c l o s e l y with l i p i d s than with carbohydrates or proteins. L i p i d s are responsible for r a n c i d i t y and oxidized f l a v o r s i n beverage milk, butter (!L) and vegetable o i l s (2) and f o r s p o i l i n g wet f i s h (3J · They are involved i n the s t a l e f l a v o r s of potato flakes (£) and baked goods ( 1 ) . L i p i d s are thought to be responsible f o r soybean reversion f l a v o r (5), f o r warmed over meat f l a v o r (6), for o l d heated cooking o i l f l a v o r (7), f o r the rancid f l a v o r s i n peanuts, coconut, coffe (j3) many others. On the other hand, l i p i d s are also responsible for much of the desireable f l a v o r of tangy cheeses such as Cheddar and roquefort (!9) , f o r the f l a v o r of fresh milk (1), for the "creamy" f l a v o r of cream (1) , for the " r i c h " f l a v o r i n heated butter (10) and f o r the c h a r a c t e r i s t i c f l a v o r s of mushrooms "(Tl) , green beans (12) , peas (13) , tomatoes (14J and cucumbers (15) and for much of the r i p e f l a v o r i n f r u i t s and b e r r i e s . The s i g n i f i c a n c e of l i p i d s to odor may well begin at the s i t e of o l f a c t i o n , at the two and a h a l f square centimeter patch of highly enervated t i s s u e located at the roof of the nasal c l e f t . Here, v o l a t i l e molecules are thought to be adsorbed and polar oriented between the l i p i d membrane portion of the nerve and the surrounding aqueous l a y e r . I t has been theorized that the adsorption and desorption of these molecules t r i g g e r s an e l e c t r i c impulse which the brain i n t e r prets (16) . How important are l i p i d s i n a r t i f i c i a l f l a v o r s ? This question was answered i n a recent survey of our f l a v o r formulations. I t was obvious that l i p i d s are the most common ingredients used both i n quantity and i n v a r i e t y . Only t e r p i n o i d compounds derived from the e s s e n t i a l o i l s of spices, woods, c i t r u s , and others compete i n t h i s regard. In the united States, there are presently 1150 v o l a t i l e compounds permitted i n a r t i f i c i a l f l a v o r s . Of these, nearly one fourth (275) are, when found i n nature, presumed to be derived from l i p i d s . Forty f i v e percent of these are esters, sixteen percent are aldehydes, t h i r t e e n percent are alcohols, nine percent are acids, nine percent are ketones and seven percent are lactones. Several

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

1.

LTTMAN AND N U M R Y C H

Positive

and

Negative

Food

Flavor

3

a r t i f i c i a l f l a v o r s are composed e n t i r e l y of l i p i d compounds while most other compositions depend heavily on them. In nature, how do these compounds a r i s e ? We know that oxidation of l i p i d s i s the f i r s t step. Autoxidation of polyunsaturated l i p i d s i s one of these mechanisms and i s of concern to the o i l chemist and the food technologists because i t i s a nonenzymatic and s e l f - s u s t a i n i n g reaction that can cause o f f - f l a v o r development, t o x i c i t y , and destruction of some o i l soluble vitamins. During the storage of processed foods and o i l s , t h e formation of hydroperoxides and t h e i r decomposition products proceeds by way of free r a d i c a l mechanisms. The production of free r a d i c a l s i s i n turn promoted by external energy sources such as heat l i g h t high energy i r r a d i a t i o n , metal heme, and others. Thes i n i t i a l products of autoxidation, w i l l , i f l e f t unchecked, decompose non-enzymatically to a v a r i e t y of strongly flavored primary and secondary compounds (Figure 1). This mechanism i s d i f f e r e n t from that which occurs i n animal and plant t i s s u e s . In animal t i s s u e , oxidation of l i p i d s occurs non-enzymatically, being i n i t i a t e d l a r g e l y by hemo-proteins which then are decomposed enzymatically. In plants, l i p i d hydroperoxides are both enzymatically formed and enzymatically decomposed (17). This brings us to the subject of l i p i d oxidation and soybean reversion f l a v o r . As soybean becomes incorporated to a greater and greater degree i n the human d i e t , the reversion f l a v o r of soy assumes more s i g n i f i c a n c e . Many of the compounds a t t r i b u t e d to the reversion f l a v o r are products of l i p i d oxidation and are characterized as "beany, buttery, painty, f i s h y , grassy, or hay l i k e " (_5) . The l i n o l e n i c a c i d component of soybean o i l has been most frequently implicated i n the formation of reversion f l a v o r where i t i s present at about nine percent (18). Soybean o i l also contains substantial amounts of o l e i c and l i n o l e i c acids as do cottonseed, corn and several other o i l s . These o i l s are not, however, subject to f l a v o r reversion but then, they only contain l e s s than one percent l i n o l e n i c acid(18). It would seem that l i n o l e n i c a c i d must occur i n subs t a n t i a l amounts together with l i n o l e i c and possibly o l e i c acids i n order for reversion products to occur. A s a t i s f a c t o r y explanation of t h i s has not yet been developed- and yet more than seventy compounds have been i d e n t i f i e d i n the v o l a t i l e f r a c t i o n s of reverted

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

Free f a t t y acids

Mono-,Di-,Tri~ Glycerides

LIPID PRECURSOR -

other r i n g structures Light Heat

Light

Heat

General scheme for lipid degradation

lactones Irradiation

Irradiation

Figure 1.

esters

hydrocarbons

ketones

alcohols C a t a l y s i s by Metallo-compds. (free metals; heme compds.)

aldehydes

acids

C a t a l y s i s by Metallo-compds, (free metals; heme compds.)

Autoxidation Enzymolysis (reductase)

Radicals

Sat. & Unsat:

-^DERIVED LIPIDS

Enzymolysis (lipoxigenase)

Autoxidation

Hydroperoxides

INTERMEDIATES

1.

L i T M A N AND N U M R Y C H

Positive

and

Negative

Food

Flavor

5

soybean. These include methyl ketones, esters, saturated and unsaturated aldehydes, and acids. These compounds can be formed i n d i f f e r e n t ways including autoxidation or by way of lipoxygenases and other enzymes to form hydroperoxides. The breakdown of hydroperoxides r e s u l t s i n the formation of hexanal, hexanol, 2-hexenal, ethyl v i n y l ketone, and 2-pentyl furan, a l l of which are characterized as "beany", or "grassy" (.5) . The 2-pentyl furan i s p a r t i c u l a r l y noteworthy because at l e v e l s as low as 1 - 1 0 ppm i t produces a beany f l a v o r while at higher concentration, i t assumes a l i c o r i c e - l i k e character ( 1 9 ) . The biogenesis of f l a v o r s i n plants also involves l i p i d oxidation. F r u i t s and vegetables have v o l a t i l e compounds that are g e n e t i c a l l y c o n t r o l l e d which are responsible f o r t h e i r f l a v o r These compounds are formed during the maturatio through s p e c i f i c enzymati disaccharides, i n the amino acids, and i n c e r t a i n unsaturated l i p i d s that contain the 1,4-pentadiene structure. These l i p i d s , mainly the l i n o l e i c and l i n o l e n i c acids, are oxidized to t h e i r hydroperoxides by action of s p e c i f i c lipoxygenases which i n turn undergo other enzymatic transformations y e i l d i n g spec i f i c aldehydes and other secondary compounds. The presence of a l i p h a t i c aldehydes i s considered an important occurance because they are not only aromat i c a l l y potent but are generally unstable. These aldehydes, together with t h e i r corresponding alcohols, are responsible f o r many of the c h a r a c t e r i s t i c f l a v o r s i n food plants including banana, apple, peas, plums and graces. Their fresh green character i s l a r g e l y due to hexanal, and 2-hexenal which derive from l i n o l e i c and l i n o l e n i c acids. The character of cucumber also derived from these l i p i d s i s mainly due to 2 nonenal and to 2,6-nonadienal and t h e i r corresponding alcohols (1!5) . In tomatoes, the fresh aroma i s due l a r g e l y to c i s - 3 - h e x e n a l , c i s - 3 - h e x e n o l , and t r a n s - 2 hexenal which derive from l i n o l e n i c acid (20i) . The p r i n c i p l e flavorant of mushroom i s l - o c t e n - 3 - o l which i s derived from l i n o l e i c acid ( 2 1 ) . The character of green beans i s i n part due to hexanal, 2-hexenal, and 1- o c t e n - 3 - o l derived from l i n o l e n i c together with l i n o l e i c acid ( 1 2 J . C h a r a c t e r i s t i c pea f l a v o r i s due to a combination of C 3 , 5 , 6 saturated alcohols, C 7 , 8 , 9 2 - enals, C 9 , 1 0 2 , 4 - d i e n a l s as well as 2-pentyl furan which are a l l derived from l i n o l e i c a c i d ( 1 3 ) . Beverage milk, an excellent v e h i c l e f o r demons t r a t i n g the nature of l i p i d f l a v o r s i s an o i l i n water emulsion. I t has a d e l i c a t e yet complex f l a v o r .

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

6

LIPIDS AS A SOURCE OF

FLAVOR

When f r e s h , i t i s acceptable to most people who might otherwise r e j e c t i t out-of-hand i f rancid or tainted f l a v o r s were detected. The normal compliment of free f a t t y acids i n milk originated through action of native l i p a s e which hydrolyzes milk f a t . These acids are located mainly i n the f a t globules from which they came and where t h e i r f l a v o r s are l a r g e l y masked, and together with short chain free f a t t y acids found i n the aqueous portion, provide milk with i t s normal f l a v o r . If the f a t t y acids located i n the f a t glob­ ules could be s h i f t e d to the serum, the r e s u l t i n g milk would be considered unacceptably rancid. Small additions of f a t t y acids to the aqueous phase are usually t o l e r a t e d but once past the threshold of r a n c i d i t y , the r e s u l t i n g milk may no longer be accept­ able. To be sure, i n some areas of the world where r e f r i g e r a t i o n i s generall gree of r a n c i d i t y i contrast, i t takes only trace q u a n t i t i e s of c e r t a i n weeds such as wild onions i n the cow's feed supply to t a i n t the f l a v o r of milk. I t was reported that as l i t t l e as two milligrams of 2,β-nonadienal s p o i l s the f l a v o r of one ton of f a t (1). Another product which depends on l i p i d s for most of i t s f l a v o r i s blue mold cheese. Here, the f l a v o r i s developed through s e l e c t i v e l i p o l y s i s of milk f a t y e i l d i n g mainly small chain saturated f a t t y acids. During the ripening period, some of these acids under­ go enzymatic ^ - o x i d a t i o n , decarboxylation, and r e ­ duction to y e i l d a mixture of f a t t y acids, methyl ketones and methyl c a r b i n o l s . Depending upon t h e i r p o l a r i t y , these compounds are p a r t i t i o n e d between the f a t and the aqueous phases of the cheese and, as i n the case of milk, the p a r t i t i o n i n g r a t i o was found to be c r i t i c a l to the normal f l a v o r ( 2 2 ) . Some of the most appetizing aromas recognized throughout the world are associated with c e r t a i n food products that have something i n common, that being that each had received heat at some point during processing. Examples of these are the aromas eminating from hot, baked bread, roasted coffee and nuts, butterscotch, barbeque, roast beef, pork, and poultry, and others. Compounds responsible for these d e l i c i o u s aromas are derived from non-enzymatic browning of sugar, aided by amino acids, and by products of l i p i d oxidation. For several years, f l a v o r manufacturers have recognized the commercial value of those f l a v o r s that evolve when mixtures of reducing sugars, amines and l i p i d s are heated together. They are searching for i d e a l conditions that recreate s y n t h e t i c a l l y

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

4

6

c

n

12

C

ClO

C9

C8

°7

C

C5

C

C3

fatty

V

fresh,citrus

fresh,green

ν

fresh,milky

Homologous Series: •Sat. fresh, pungent C2

2

2

0

1

2-Enals

4

5

)

8

Flavor, (+)(-)

+

c

8

xi

&

+

beef

2,4r-Dienals Flavor,(+)(-) 2,6-nonadienal: (-)linseed o i l (+)cis-4-heptenal: (+)cucurriber butter,cream (1) (-fJO^gpork (23) (32)(15) (+)C _i6beef (24) sweet,pungent (+)C 6_i2ham (27) (-)C7,10° dized jrçilk sweet,green (-)C4_nskim milk (+)C _5Coffee, (1) (28) cocoa (-)°7,10^ oxidized (+)Cgfruit (-)C _ soy & veg. veg.oil oils (25) sweet,oily (-)Cgveg.oils, (30) ( - ) Ct^QOxidized skim milk (25) milk (1) ( )Cr,9-12 ham (23) (+)C3_9gr.veg. (26) sweet,fatty, green (+)C H O — C — H

R—C—O—C—Η

2

H

+ 3RCOOH

+

Ο

CH OH

CH —O—C—R

2

2

Figure 3.

Actions of lipase

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

H A Y M O N AND ACTON

Fhvors

from Lipids

by Microbiological

Action

99

l a c t i c a c i d b a c t e r i a are a c t i v e l i p a s e producers, while others o f the same c l a s s i f i c a t i o n do not produce s i g n i f i c a n t l i p a s e activity. A l f o r d , Smith and L i l l y (1971) have shown the h y d r o l y t i c and o x i d a t i v e changes due to M i c r o c o c c i , Pseudomonas, and Staphylococci. They showed that the h y d r o l y t i c a c t i v i t y o f microorganisms i s dependent on (1) the f a t used as a s u b s t i t u t e , (2) temperature of i n c u b a t i o n , (3) composition of the growth media, and (4) oxygen a v a i l a b i l i t y . Table I from A l f o r d & P i e r c e (1961) shows the e f f e c t of temperature on the type of f a t t y a c i d s released by m i c r o b i a l l i p a s e s from coconut o i l . Lipases of b a c t e r i a i s o l a t e d from r a n c i d b u t t e r (by Cooke 1973) showed that Pseudomonas, S. aureus, Micrococcus saprophyticus, Micrococcus spp., and a p a n c r e a t i c l i p a s e produced v a r y i n g amounts of C ^ , C]_4> 1 6 » ^18» ^18:1 f a t t y a c i d s from m i l k f a t a t 35, 30, and 22°C. In c o n t r a s t to e a r l i e r f i n d i n g s , Micrococcu a c i d a t high temperatures A high carbohydrate substrate w i l l i n h i b i t or reduce l i p a s e production (Nashif & Nelson, 1953; A l f o r d & E l l i o t t , 1960) and the p r o t e i n , peptides or amino a c i d s used as sources of n i t r o g e n are important c o n s i d e r a t i o n (Lawrence et a l . , 1967; A l f o r d & P i e r c e , 1963). c

TABLE I Influence Of Temperature On Type Of F a t t y Acids Released By M i c r o b i a l Lipases From Coconut O i l ( A f t e r A l f o r d & P i e r c e , 1961)

% Of T o t a l Free F a t t y A c i d s * Released As Lipase From

Pseudomonas F r a g i Geotrichum Candidurn Pénicillium R o q u e f o r t i i

L a u r i e A c i d At

O l e i c A c i d At

35°

-7°

35°

-7°

46 39 46

29 3 35

5 14 4

25 52 24

*Conditions of i n c u b a t i o n of enzyme-coconut o i l mixtures and % of other f r e e f a t t y a c i d s r e l e a s e d a r e given i n the o r i g i n a l paper.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

100

LIPIDS AS A SOURCE OF

FLAVOR

Vigorous a e r a t i o n decreases l i p a s e production or at l e a s t i t s accumulation, yet growth i n media with high surface/volume r a t i o s such as sausages or w i t h slow a g i t a t i o n i s stimulatory (Nashif & Nelson, 1953; A l f o r d and E l l i o t t , 1960; A l f o r d & Smith, 1965; Lawrence et a l . , 1967). Lipase S p e c i f i c i t y Table I I shows the determination of s p e c i f i c i t y of m i c r o b i a l l i p a s e s by t h e i r a c t i o n on t r i g l y c e r i d e s of known composition ( A l f o r d et a l . , 1964). There appears to be good evidence of s p e c i f i c i t y r e l a t e d to the p o s i t i o n of attachment of a f a t t y a c i d to the t r i g l y c e r i d e molecule ( A l f o r d et a l . , 1964; Mencer & A l f o r d , 1967) and to the s t r u c t u r e of the f a t t y a c i d being hydrolyzed (Jensen et a l . , 1965). Other l i p a s e s are very general with no s p e c i f i c i t y . The Geotrichum candidum i s s p e c i f i c for o l e i c acid regardles s p e c i f i c f o r the 1 - p o s i t i o S. aureus l i p a s e e x h i b i t s n e i t h e r p o s i t i o n nor f a t t y a c i d specificity. TABLE I I Determination Of S p e c i f i c i t y Of M i c r o b i a l Lipases By T h e i r A c t i o n On T r i g l y c e r i d e s Of Known Composition (After A l f o r d , P i e r c e & Suggs, 1964)

% Composition Of L i p a s e From

2-01eoyl D i s t e a r i n Oleic Acid

Geotrichum Candidum Pseudomonas F r a g i Staphylococcus Aureus

Stearic Acid

98* 2 25

* % Of t o t a l f r e e f a t t y acids released mixture incubated at 35° from 1-3 H.

2 28 75

Triglyceride 2-Stearolyl Diolein Oleic Acid

99 98 63

Stearic Acid

1 2 37

from e n z y m e - t r i g l y c e r i d e

Smith & A l f o r d (1966) have shown that the production and a c t i v i t y of some l i p a s e s are s e n s i t i v e to end-product accumulat i o n i n h i b i t i o n . T h e i r studies were performed w i t h Ps. f r a g i , and the end-product i n h i b i t i o n was e l i m i n a t e d by the a d d i t i o n of bovine serum.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

H A Y M O N AND ACTON

Oxidative

Fhvors

from Lipids

by Microbiological

Action

101

Reactions

A l f o r d and Smith (1971) have shown the a c t i o n of microorganisms on the peroxides of r a n c i d l a r d , shown i n "Figure 4". The e f f e c t v a r i e d from 18% decomposition by Ps. o v a l i s and Streptomyces sps. to 100% decomposition of the peroxides by G. candidum and A s p e r g i l l u s f l a v u s . F i f t e e n c u l t u r e s of the 29 s t u d i e s showed a 50% r e d u c t i o n i n the peroxide value. The a c t i o n of microorganisms on the mono carbonyls was shown by A l f o r d and Smith (1971). "Figure 5" and "Figure 6" show that Ps. f r a g i , Ps. o v a l i s , and G. candidum destroyed 100% of the 2, 4 d i e n a l f r a c t i o n while Asp, f l a v u s and M. f r e u d e n r e i c h i i increased the d i e n a l content 4 to 7 f o l d . F i f t e e n c u l t u r e s of the 29 studied decreased the d i e n a l concentration. Only 5 c u l t u r e s of the 29 increased the d i e n a l concentration by a f a c t o r of 2. "Figure 7" shows the e f f e c t of microorganisms on peroxides in fresh lard. Ten of the small amount of peroxid had no e f f e c t . F i v e s t r a i n s of Streptomyces increased the peroxide concentration about 3 f o l d , Ps. o v a l i s increased the concentration by 8 f o l d , and M. f r e u d e n r e i c h i i increased the peroxides about 14 f o l d . A l f o r d & Smith (1971) reported that M. f r e u d e n r e i c h i i produced a l a r g e increase i n the concentration of 2, 4 d i e n a l s and 2 enals. Most of the microorganisms had l i t t l e e f f e c t on the a l k a n a l f r a c t i o n . Ps. f r a g i , G. candidum, and C. l i p o l y t i c a increased the concentration of the a l k a n a l s as w e l l as producing methyl ketones, a f r a c t i o n not present i n f r e s h l a r d . The a b i l i t y of Streptomyces spp., Ps. o v a l i s , and M. f r e u d e n r e i c h i i to form peroxides suggests that l i p o x i d a s e l i k e a c t i v i t y i s present. I t was reported that microorganisms produce l i p o x i d a s e (Mulkerjee, 1951; Fukuba, 1953; Shimahara, 1966), but Tapel (1963) s t a t e d there i s no evidence f o r a m i c r o b i a l l i p o x i d a s e . The precursors f o r methyl ketone production by the studied b a c t e r i a a r e unknown, but these organisms a r e s t r o n g l y l i p o l y t i c and f u n g i a r e known t o produce methyl ketones by B-oxidation and decarboxylation of l i p a s e l i b e r a t e d f a t t y acids (Hanke, 1966). Sausage Products The type of f a t used i n the p r e p a r a t i o n of d r y sausage w i l l i n f l u e n c e f l a v o r c h a r a c t e r i s t i c s , p a r t i c u l a r l y as the f a t s h i f t s from a l l beef formulations to a l l pork formulations. The d i s t i n c t i v e f l a v o r s of d r y sausages a r e due i n part to the h y d r o l y t i c and o x i d a t i v e changes that occur i n the l i p i d f r a c t i o n during r i p e n i n g or d r y i n g . Lipase A c t i v i t y . The h y d r o l y t i c changes i n f a t s a r e due p r i m a r i l y to the a c t i o n o f b a c t e r i a which produce l i p a s e s . These m i c r o b i a l l i p a s e s a c t to f r e e f a t t y a c i d s and g l y c e r o l . I n d r y

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

LIPIDS AS A SOURCE O F FLAVOR

lOOr

Control Streptomyces PovaHs PS

80 μ freudenrehhff

60

40

Pfragi

C.

20

lipolytica G.candidum A.flavus Figure 4. The effect of micro-organisms on the peroxides of rancid lard. The initial peroxide values ranged 74.3-97.4 meq/kg of fat (mean, 82.9 meq).

M.

7

freudenreichii r

*5| ι

cvT

A.flovus

2h Control R

f

m

g

.

Strep*****

c

Povatis lipolytica G.candidum^ j

Figure 5. The effect of micro-organisms on the 2,4-dienals of rancid lard. The 2,4-dienal concentration of the controls ranged 1.5-3.4 ^moles/10 ^moles fat (mean, 2.0 ymoles). 4

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

H A Y M O N AND ACTON

Fhvors

from Lipids by Microbiological

Action

M freudenreichff

l-5r

Pfragi Aflavus CM

Povalis

Control

σ 0-5

C

SfrepfOmyces\ sp

6. candidum\ Figure 6. The effect of micro-organisms on the 2-enals of rancid fat. The 2-enal concentration of the controls ranged 3.6-6.7 fimoles/10 ^moles fat (mean, 5.0 pmc-les). 4

M.

70r

freudenreichff

60h

50 Povalis

r40

Î30

Streptornyces sp.

"20

Control

Figure

7.

14 micro10 organisms! microorganisms!

The effect of micro-organisms on peroxides in fresh lard

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

104

LIPIDS AS A SOURCE O F

FLAVOR

sausage, where no heat i s a p p l i e d to the product, h y d r o l y s i s may occur through muscle and adipose t i s s u e l i p a s e s (Wallach, 1968). The p a r t i c u l a r f l a v o r developed by the sausage v i a l i p a s e a c t i v i t y depends on the composition of the f a t as seen from the work of A l f o r d and Smith (1971). The genus Microcococcus i s g e n e r a l l y accepted as being the predominant group of microbes r e s p o n s i b l e f o r h y d r o l y s i s of f a t s i n dry sausage (Table I I I ) (Cantoni et a l . , 1967), but recent s t u d i e s show that some species of L a c t o b a c i l l i produce very a c t i v e l i p a s e s at 20°C and higher (Stoychev et a l . , 1972a, 1972b; C o v e t t i , 1965).

TABLE I I I A c t i o n of M i c r o c o c c i on Pork Fat (fro

Culture DIP C

4

c

" 20>

G

F

A/100 G F A T

A

C13

23.1

45.2

87

50

660

667

(FA most e a s i l y r e l e a s e d : O l e i c , Myristic, Palmitoleic, Linoleic) V o l a t i l e FA, MG/100 G F A T ( p r i n c i p a l VFA: Acetic) Carbonyls, uM/1

B

Propionic,

of C u l t u r e

0

( p r i n c i p a l carbonyls: Propionaldehyde, Isovaleraldehyde)

A f t e r 28 days of c u l t u r e ; FA - F a t t y A c i d . l

A f t e r 28 days of c u l t u r e ; VFA

- V o l a t i l e Fatty Acid.

'After 24 days of c u l t u r e .

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

H A Y M O N AND ACTON

Flavors from Lipids

by

Microbiological

Action

105

M i h a l y i and Kormendy (1967) reported an i n c r e a s e i n f r e e f a t t y a c i d values i n the inner and outer zones of a Hungarian dry salami aged f o r 100 days (Table IV). The outer zone showed a higher l e v e l of f a t t y a c i d s than the inner zone. Since there i s mold accumulation on Hungarian salami, the increase was a t t r i b u t e d to t h i s mold growth.

TABLE IV Free F a t t y A c i d Values (mg KOH/g f a t ) of Hungarian Dry Salami During Ripening*

Days Of Ripening

Sausage P o r t i o n Inner Zone Outer Zone

10

6.0

40

11.28

12.40

70

14.81

18.29

100

17.68

20.62

*Adapted from M i h a l y i and Kormendy (1967). Lu and Townsend (1973) a l s o showed increases i n f r e e f a t t y a c i d values during the d r y i n g c y c l e and c o r r e l a t e d t h e i r r e s u l t s with p a r a l l e l peroxide values (Table V). Demeyer et a l . (1974) reported that l i n o l e i c a c i d was l i b e r a t e d at a f a s t e r r a t e than a l l of the other a c i d s i n a pork dry sausage ("Figure 6"). Brockerhoff (1966) has shown that pork t r i g l y c e r i d e s have about 60% of the s t e a r i c a c i d l o c a t e d i n p o s i t i o n 1, p a l m i t i c a c i d (^ 60-80%) at p o s i t i o n 2, and o c t a decenoic a c i d (^ 50-60%) are at p o s i t i o n 3 of the t r i g l y c e r i d e molecule. Demeyer et a l . (1974) found the r a t e of h y d r o l y s i s to f r e e f a t t y a c i d s decreased i n the f o l l o w i n g order: linoleic > o l e i c > s t e a r i c > p a l m i t i c . The l i p a s e g e n e r a l l y had a s p e c i f i c i t y f o r p o s i t i o n 3. C e r i s e et a l . (1973) reported that o l e i c a c i d was the p r i n c i p a l f r e e f a t t y a c i d found i n the l i p i d f r a c t i o n of I t a l i a n pork salami. Dobbertin et a l . (1975) reported yeasts, pseudomonads, and e n t e r o c o c c i which e x h i b i t e d high l i p a s e a c t i v i t y , but the l a c t o b a c i l l i had l i t t l e or no l i p a s e a c t i v i t y . Dobbertin concluded that l i p a s e a c t i v i t y was independent of t o t a l b a c t e r i a l count. However, C o r e t t i (1965) found that some l a c t o b a c i l l i

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

106

LIPIDS AS A SOURCE OF

FLAVOR

appear to form l i p a s e a c t i v i t y a d a p t i v e l y i n l a t e r generations. Fryer et a l . (1967) and Oterholm (1968) have reported l i p o l y t i c a c t i v i t y f o r l a c t o b a c i l l i of t r i b u t y r i n , but not t r i g l y c e r i d e s .

TABLE V Free F a t t y A c i d Values (mg KOH/g f a t ) and Peroxide Values of a Fermented Dry Salami*

Days Of Ripening

0

Free F a t t y A c i d Value

Peroxide Value

3.08

10.3

21

6.90

12.9

28

6.56

16.9

35

11.66

20.6

14

* C a l c u l a t e d from data f o r c o n t r o l sausages i n study of Lu and Townsend (1973).

The Pseudomonas, M i c r o c o c c i , and S t a p h y l o c o c c i are a c t i v e l i p a s e organisms. Debevere et a l . (1976) from Belgium have reported the i s o l a t i o n of a Micrococcus species from a s t a r t e r c u l t u r e used f o r producing dry sausages, which has a strong l i p o l y t i c a c t i v i t y on pork f a t . T h i s species caused the r e l e a s e of f a t t y a c i d s from pork f a t i n a n o n s p e c i f i c way but i n about the same proportions that occur i n pork f a t . Both saturated and unsaturated carbonyls were formed from the long chain f a t t y a c i d s . The unsaturated carbonyls disappeared f a s t e r than the saturated carbonyls, apparently due to o x i d a t i o n . The breakdown of the saturated carbonyls appeared to be due to the a c t i o n of the b a c t e r i a , perhaps by producing enzymes capable of h y d r o l y z i n g these compounds. The b a c t e r i a may play an important r o l e i n the development of f l a v o r by r e l e a s i n g and h y d r o l y z i n g the carbonyl compounds, and producing short chain v o l a t i l e compounds that c o n t r i b u t e to f l a v o r . O x i d a t i v e Changes i n Sausages. C e r i s e reported two d i s t i n c t phases of l i p i d changes. In the e a r l y r i p e n i n g phase of ferment-

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

H A Y M O N AND ACTON

Fhvors

from Lipids by Microbiological

Action

107

a t i o n , l i p a s e a c t i v i t y occurred to y i e l d f r e e f a t t y a c i d s , which were i n turn o x i d i z e d by peroxides to carbonyl compounds i n the d r y i n g phase. Free f a t t y a c i d s decreased as the amount of carbonyl compounds increased. C e r i s e (1972) showed that peroxide values decrease r a p i d l y a f t e r the fermentation phase ("Figure 8"). Peroxide values increased d r a m a t i c a l l y between the second and f o u r t h days at 21°C and remained high before decreasing to below i n i t i a l l e v e l s at 15 days of r i p e n i n g . Nurmi (1966) reported n e a r l y equivalent amounts of peroxide formation at 3 days of sausage r i p e n i n g with M i c r o c o c c i and/or l a c t o b a c i l l i . A f t e r the 3 day fermentation p e r i o d , sausages c o n t a i n i n g l a c t o b a c i l l i continued to show peroxide at higher l e v e l s than i n i t i a l l y observed. Both m i c r o c o c c i and l a c t o b a c i l l i can be strong producers of peroxide. While m i c r o c o c c i are c a t a l a s e - p o s i t i v e , l a c t o b a c i l l i are c a t a l a s e - n e g a t i v e . Nurmi (1966) pointed out that f a u l t y product f l a v o r and c o l o r may r e s u l t when c a t a l a s e - n e g a t i v f o r sausage r i p e n i n g . Hydrogen peroxide, which i s formed by the p e d i o c o c c i , and l a c t o b a c i l l i , i s an a v a i l a b l e and w i l l i n g reactant i n the o x i d a t i o n of f r e e f a t t y a c i d s generated by l i p o l y s i s , e s p e c i a l l y unsaturated f a t t y a c i d s (Tjaberg, 1969). A l s o , f a t t y a c i d o x i d a t i o n may r e s u l t from a u t o o x i d a t i o n mechanism. Carbonyl compounds are formed as a d i r e c t r e s u l t of unsaturated f a t t y a c i d decomposition. The e v a l u a t i o n of t o t a l carbonyl compounds f o r a dry sausage made p r i m a r i l y w i t h pork f a t i s shown from Demeyer et a l . (1974). Halvarson (1973) q u a l i t a t i v e l y i d e n t i f i e d some 22 v o l a t i l e carbonyl compounds from Swedish fermented sausage. The predominant substances were ethanal, propanal, propanone, and 2-methyl and 3-methyl butanal i n concentrations of 0.6 to 3.6 mg. per kg. of sausage. A l l the s t r a i g h t chain a l k a n a l s were detected up to o c t a n a l , w i t h no butanal detected, as w e l l as methyl ketones, 2-alkenals, and 2, 4 - a l k a d i e n a l s . Langer et a l . (1970) reported q u a l i t a t i v e i d e n t i f i c a t i o n of 29 carbonyl compounds during the r i p e n i n g of a dry salami. Langer et a l . (1970) and Halvarson (1973) considered the lower molecular weight carbonyls (probably from carbohydrate fermentation) to possess minimal values f o r c h a r a c t e r i s t i c sausage aroma, and both authors s t a t e that the main aroma producers are the higher molecular weight carbonyls. In p a r t i c u l a r , unsaturated carbonyls such as 2-alkenals and the 2, 4 - a l k a d i e n a l s , are potent f l a v o r compounds t y p i c a l l y present i n o x i d i z e d pork f a t , and present to a l i m i t e d extent i n o x i d i z e d beef f a t (Hornstein and Crowe, 1960; 1963). Cheese Cheese i s a fermented d a i r y product which has a high f a t content. The l i p i d changes i n cheese must help determine the f i n a l f l a v o r of t h i s h i g h l y f l a v o r e d product. Sometimes, f l a v o r s

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

LIPIDS AS A SOURCE O F FLAVOR

45 STORAGE

30

0 12 3 4 6 8 15 « «—DAYS IN RIPINING (2ΓΟ (Ι2

Figure 8. Peroxide values during sausage ripening (0 to 3 days at 21°C, then stored at 12°C) (adapted fromRef. IS)

300-

es 275

i

-

DEMEYER etc*/. (1974)

250-

/ /

1

225UK 2 200-

ι l

I

•

/

/

ZD Ο Q.

175 S 8 150 >~

CAR

ζ m

125 100 - j Ο

/

\

/

if'

7

ι

ι

5

10

ι

15

ι

ι

20 25

ι

ί-

30 35

40 45

DAYS OF RIPENING Figure 9. Changes in total carbonyl content (as 24-dinitrophenylhydrazones) during dry sausage ripening (adapted from Ref. 20)

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

H A Y M O N AND ACTON

Ffovors from Lipids

by Microbiological

Action

Journal of Food Science Figure 10. Percent of total palmitic (16:0), stearic (18:0), oleic (18:1) and linoleic (18:2) acid present in the free fatty acid fraction (20)

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

109

110

LIPIDS AS A SOURCE O F FLAVOR

of cheeses are described as soapy, b i t t e r , m e t a l l i c , barn-yard ( b u t y r i c ) , o r r a n c i d . These f l a v o r s are caused by the accumula­ t i o n of f r e e f a t t y a c i d s . The short chain f a t t y a c i d s have low t a s t e thresholds and need only be present i n minute concentrations to produce f l a v o r s . Deeth and F i r z g e r a l d (1976) have reviewed the l i t e r a t u r e thoroughly f o r l i p o l y s i s i n milk-products.

TABLE VI V o l a t i l e F a t t y A c i d s Reported In Dry Sausages

Acid

Deketelaere et a l . (1974)

Halvarson (1973) Nonsmoked Smoked mg/g sausage

Formate

-

0.25

0.42

Acetate

2.4 mM/100 g D.M.

0.70

1.2

Propionate

11.7 μΜ/100 g D.M.

0.004

0.03

n-Butyrate

14.5 μΜ/100 g D.M.

0.004

0.007

The most common source of l i p a s e other than m i l k l i p a s e i s from psychrotrophic b a c t e r i a , those which grow a t r e f r i g e r a t i o n temperatures. Deeth s t a t e s that "when the count of these l i p o l y t i c b a c t e r i a exceed one m i l l i o n per m i l l i l i t e r they cause r a n c i d f l a v o r s . " However, cheeses such as Romano, the Parmesan and blue v e i n types depend f o r t h e i r d i s t i n c t i v e t a s t e s upon r e l a t i v e l y high l e v e l s of p a r t i c u l a r f a t t y acids which are produced by rennet or m i c r o b i a l and fungal l i p a s e s during maturation. The cheddar cheese f l a v o r i s reported by Deeth (1976) as a balance between f a t t y acids produced i n low amounts during normal aging and other f l a v o r c o n s t i t u e n t s . Peterson and Johnson (1949) i s o l a t e d 12 of 54 l a c t o b a c i l l i which possessed i n t r a c e l l u l a r l i p a s e a c t i v e between pH 5 and 6, and were capable of b u t t e r f a t h y d r o l y s i s . L. c a s e i (four strains) was p a r t i c u l a r l y a c t i v e and l i b e r a t e d b u t y r i c , c a p r o i c , c a p r y l i c , and c a p r i c acids from b u t t e r f a t . M o r r i s and J e z e s k i (1953) c h a r a c t e r i z e d the l i p a s e system of P e n c i l l i u m r o q u e f o r t i . Lawrence and Hawke (1968) found that the f a t t y acids l i b e r a t e d from P. r o q u e f o r t i gave o x i d a t i o n products dependent on the f a t t y a c i d concentration, chain length of f a t t y a c i d s , and pH of the system. The studies were conducted by oxygen uptake.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

8.

H A Y M O N AND ACTON

Flavors from Lipids by Microbiological

Action

111

Lubert and F r a z i e r (1955) studied c u l t u r e s o f f i l m yeasts and of m i c r o c o c c i from b r i c k cheese and cheese b r i n e s . The m i c r o c o c c i found were predominantly M. v a r i a n s , M. c a s e o l y t i c u s , and M. f r e u d e n r e i c h i i ( i n order of occurrence). Growth of m i c r o c o c c i with f i l m yeasts i n d i c a t e d the yeasts stimulated the growth of the c o c c i on the surface of b r i c k cheese smear. B u t y r i c and a c e t i c a c i d s were i d e n t i f i e d as products of growth, but the f r a c t i o n with the c h a r a c t e r i s t i c odor contained higher fatty acids. Kaderavek e t a l . (1973) have shown that i n m i l k products, l a c t i c a c i d b a c t e r i a hydrolyze only short chain f a t t y a c i d s . M i c r o c o c c i from I t a l i a n cheeses a r e p r o t e o l y t i c and n o n s p e c i f i c a l l y l i p o l y t i c , p r o p i o n i c a c i d b a c t e r i a l i p a s e s a r e n o n s p e c i f i c and product b u t y r i c , i s o v a l e r i c , and v a l e r i c a c i d s . They a l s o found yeasts were l i p o l y t i c and mold l i p a s e s were n o n s p e c i f i c . Summary F l a v o r s a r e generated from l i p i d s by m i c r o b i o l o g i c a l a c t i o n . The m i c r o b i o l o g i c a l a c t i o n on l i p i d s was shown f o r l a c t i c a c i d b a c t e r i a , M i c r o c o c c i , Staphylococci, Pseudomonas, yeast, and mold. The l i p a s e r e a c t i o n s f o r b a c t e r i a and mold a r e c h a r a c t e r i s t i c a l l y d i f f e r e n t f o r each type of organism and can d i f f e r by s p e c i f i c i t y w i t h i n c l a s s e s . Large d i f f e r e n c e s i n the l a c t i c a c i d b a c t e r i a l i p a s e s were noted. M i c r o c o c c i l i p a s e s a r e perhaps the most s t u d i e d , and t h e r e f o r e the most defined. H y d r o l y t i c and o x i d a t i v e r e a c t i o n s by the b a c t e r i a a r e , i n general, ubiquitous r e g a r d l e s s of product. The general scheme of an increase i n f r e e f a t t y a c i d s , mono and d i - c a r b o n y l s , and an increase i n peroxide value, TBA, and t o t a l acids accompany the increase i n f r e e f a t t y a c i d s . The f l a v o r s of dry sausages and cheeses a r e dependent on the a c t i o n of b a c t e r i a w i t h i n and outside of the product. The f l a v o r s of cheeses and sausages a r e dependent upon (1) the s p e c i f i c organisms, (2) l i p a s e s produced by the organism, and (3) the substate furnished f o r the organism.

Literature Cited 1. Alford, J. A. and L. E. Elliott. Lipolytic activity of microorganisms at low and intermediate temperatures I. Action of Pseudomonas fluorescens on lard. Fd Res. (1960) 25, 296. 2. Alford, J. A. and D. A. Pierce. Lipolytic activity of microorganisms at low and intermediate temperatures III. Activity of microbial lipases at temperatures below 0°C. J. Food Sci. (1961) 26, 518.

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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LIPIDS AS A SOURCE O F FLAVOR

3. Alford, J. A. and D. A. Pierce. Production of lipase by Pseudomones fragi in a synthetic medium. J. Bacti. 86, 24. 4. Alford, J. Α., D. A. Pierce, and F. G. Suggs. Activity of microbial lipases on natural fats and synthetic triglycerides. J. Lipid Res. (1964) 5, 390-394. 5. Alford, J. Α., D. A. Pierce, and W. L. Sulzbacker. Microbial lipases and their importance to the meat industry. Proc. Res. Conf. Advisory Council Res. Am. Meat Ind. Found. Univ. Chicago. (1963) 15, 11-16. 6. Alford, J. A. and J. L. Smith. Production of microbial lipases for the study of triglyceride structure. J. Am. Oil Chem. Soc. (1965) 42, 1038. 7. Alford, J. Α., J. L. Smith, and H. D. Lilly. Relation of microbial activity to changes in lipids of foods. J. Appl. Bacteriol. (1971) 34, 133-146. 8. Aurand, L. W. and A. E. Woods. Food Chemistry, The AVI Publishing Company 9. Blood, M. R. Lacti "Lactic Acid Bacteria in Beverages andFood",Academic Press, New York, (1975). 10. Brockerhoff, H. Fatty acid distribution patterns of animal depot fats. Comp. Biochem. Physiol. (1966) 19, 1. 11. Cantoni, C., R. Molnar, P. Renon, and G. Giolitti. Lipids of dry sausages. Behavior of lipids during maturation. Ind. Conserve. (1966) 41, 188-197. CA. 66, 27809v (1967). 12. Cantoni, C., R. Molnar, P. Renon, and G. Giolitti. Micrococci in pork fat. J. Appl. Bacteriol. (1967) 30, 190-196. 13. Cerise, L . , V. Bracco, I. Horman, T. Sozzi, and J. J. Wuhrmann. Changes in the lipid fraction during the ripening of pure pork salami; "Proceedings: 18th Annual Meeting of European Meat ResearchWorkers",pp. 382-389. University of Guelph, Guelph, Ontario, Canada (1972). 14. Cerise, L . , V. Bracco, I. Horman, T. Sozzi, and J. J. Wuhrmann. Changes in the lipid fraction during ripening of a pure pork salami. Fleischw 53, 223 (1973). 15. Collins, Ε. B. Biosynthesis of flavor compounds by micro­ organisms. "Journal of DairyScience",55, 1022-1028. (1972). 16. Cooke, B. C. Influence of incubation temperature on microbial lipase specificity. N.Z.J. Dairy Sci. Technol. 8, 126-127. (1973). 17. Coretti, K. The occurance and significance of lipolytic microorganisms in salami-type sausages intended for long storage. Fleischw. 45, 33. (1965). 18. Debevere, et al. Title unknown. Lebensmittel-Wissenschaft und Technologie. 9: 160. In the National Provisioner, 176, 83. (1976).

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19. 20. 21.

22. 23. 24. 25. 26. 27. 28.

29. 30. 31. 32. 33. 34.

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35. Mencher, J. R. and J. A. Alford. Purification and characterization of the lipase of Pseudomonas fragi. J. Gen. Microbial., 48, p. 317. (1967). 36. Mihalyi, V. and L. Kormandy. Changes in protein solubility and associated properties during the ripening of Hungarian dry sausages. Food Technol., 21, pp. 1398-1402. (1967). 37. Morris, H. A. and J. J. Jezeski. The action of microorganisms on fats. II. Some characteristics of the lipase system of Pencillium roqueforti. J. Dairy Sci., 36, pp. 1285-1298. (1953). 38. Mukherjee, S. Studies on degradation of fata by microorganisms. I. Preliminary investigations on enzyme systems involved in the spoilage of fats. Arch. Biochem. 33, p. 364. (1951). 39. Nashif, S. A. and F. E. Nelson. The lipase of Pseudomonas fragi. II. Factors affecting lipase production J Dairy Sci., 36, p. 471 40. Nurmi, E. Effect tics and microbial flora of dry sausages. Acta Agralia Fennica, p. 108. (1966). 41. Peterson, M. H. and M. J. Johnson. Delayed hydrolysis of butterfat by certain lactobacilli and micrococci isolated from cheese. J. Bact., 58, pp. 701-708. (1949). 42. Schelhorn, M. Cause of lipolysis in dry sausages studied with models. Fleischwirtschaft, 52, pp. 72-75. (1972). 43. Shimahara, K. Bacterial peroxidation of fats. III. Identification of lipoxygenase-forming bacteria. J. Ferment. Technol., Osaka. 44, p. 230. (1966). 44. Smith, J. L. and J. A. Alford. Action of microorganisms on the peroxides and carbonyls of rancid fat. J. Food Sci. 33, pp. 93-97. (1968). 45. Smith, J. L. and J. A. Alford. Action of microorganisms on the peroxides and carbonyls of fresh lard. J. Food Sci. 34, pp. 75-78. (1969). 46. Smith, J. L. and J. A. Alford. Inhibition of microbial lipases by fatty acids. Appl Microbial. p. 14, 699. (1966). 47. Stoychev, M. G. Djejava, and R. Brankova. Impact of pH and different NaCl concentrations on the lipase activity of starter cultures used in connection with the production of raw dried meat products. "Proceedings: 18th Annual Meeting of European Meat ResearchWorkers",pp. 113-118. University of Guelph, Guelph, Ontario, Canada. (1972b). 48. Stoychev, M., G. Djejeva, and R. Brankova. Studies on lipase activity of some starter cultures at temperatures used in the manufacture and storage of raw-dried meat production. "Proceedings: 18th Annual Meeting of European Meat Research Workers", pp. 105-109. University of Guelph, Guelph, Ontario, Canada. (1972a).

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

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from Lipids

by Microbiological

Action

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Tappel, A. L. Lipoxidase."TheEnzymes",Vol. 8. Editors: P. D. Boyer, H. Lardy, and K. Myrback. Academic Press, New York. (1963). 50. Tjaberg, T. Β., M. Haugam, and E. Nurmi. Studies on discoloration of Norwegian salami sausage. "Proceedings: 15th European Meeting of Meat Research Workers", August 17-24, 1969, Helsinki, Finland, pp. 138-148. (1969). 51. Wood, J. B., O. S. Cardenas, F. M. Yong, and D. W. McNulty. Lactobacilli in production of soy sauce, sour-dough bread, and Parisian barm. "Lactic Acid Bacteria in Beverages andFood",Academic Press, New York. (1975). RECEIVED

December 22, 1977

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

INDEX A Acid(s) aliphatic 12 aroma generated by different amino 24 citric 83 hydroperoxides, linoleic 91 Acidulants 1 Alcohol groups 1 Alcohols, aliphatic 8 Aldehydes 49 aliphatic 1, saturated 4 Aliphatic acids 12 alcohols 8 aldehydes 7 compounds as they relate to flavor .. 9 ethyl esters 14 Alkenals 42 Amino acids, aroma generated by different 24 Animal fat 94 Antioxidants 73 Aroma(s) 6 compounds by photooxidation of unsaturated fatty esters, generation of 56 fruit 60 generated by different amino acids 24 vegetable 60 Artificial flavors 3 Aspergillus

flavus

Autoxidation of polyunsaturated lipids

101

3

Β Bacon Bacteria, biochemical reaction of Bacteria, lactic acid Berries Biochemical reaction of bacteria Bitterants

66 96 96 2 96 1

C Carbinols, methyl Catalysts, oxidation Cheese(s) blue mold tangy

11 73 94,107 6 2

Citric acid 83 Coconut oil(s) 44-46 influence of temperature on type of fatty acids, released by micro­ bial lipases from 99 Composition and structure, lipid 72 Computer loop, gas chromatogram .... 85 Concentration of some volatiles used in frying shortenings as compared to those in heated corn oil Corn oil volatile compounds in Cottonseed oil hydrogenated

22,38-46 50, 54 21, 22 38

D Deboning, mechanical 77 Decadienals 52 Decomposition products of frying, systematic identification of the volatile 25 and minor constituents 40 nonvolatile (NVDP) 18 volatile 18,30-37,44 Dienals 42 Diglycerides 1

Ε Enzyme, superoxide dismutase Epoxides, formation of Ester(s) aliphatic ethyl generation of aroma compounds by photooxidation of unsaturated fatty groups

70 90 14 56 1

F Fat(s) action of micrococci on pork animal comparative study, volatiles from frying fried flavor, chemistry of deep fried foods, volatileflavorcon­ stituents (VFC) in deep-

117

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

104 94 42 18 19

LIPIDS AS A SOURCE O F FLAVOR

118

Flavor(s) (continued) Fat(s) (continued) stability of soybean oil* milestones frying 1 in improving 82 deep 20 stale 2 oils and fat used for simulated .... 39 Food(s) of potatoes 94 chemical changes involved in the milk oxidation of lipids in 68 used for simulated deep-fat frying 20 lipid oxidation in various flesh 74 oils and J and the oil, volatileflavorconFatty acid(s) QQ stituents produced by the inter­ hydroperoxides, unsaturated action between the 21 oxidative (enzyme) cyclization of -ο products, instrumental analysis of polyunsaturated volatiles in 60 released by microbial lipases from role lipids play in the positive and coconut oil, influence of tem­ negative flavors of 1 perature on type of 99 used for frying, volatileflavorconreported in dry sausages, volatile .... 110 stituents originated from the .... 21 values of a fermented dry salami, volatileflavorconstituents (VFC) free 106 in deep-fat fried 19 values of Hungarian dry salami, free 105 Fruit aromas 60 Fatty esters, generation of arom compounds by photooxidation of Frying 56 oils and fat used for simulated unsaturated 76 deep-fat 20 Fish tissue 24 of potatoes, deep-fat 39 Flavor(s) systematic identification of the volaaliphatic compounds as they 9 tile decomposition products of 25 relate to artificial 3 chemistry of deep fat fried 18 G constituents, volatile (VFC) 19 Gas chromatogram computer loop .... 85 in deep-fat fried foods GC analysis, comparison of oil flavor originated from the food used 21 scores obtained by taste panels for frying and direct 64 produced by the interaction 21 Geotrichum candidum 100,101 between the food and the oil 3 Glycerides, oxidized 18 development, offGlycerides, polymerized 18 of foods, role lipids play in the I Glycerol 1 positive and negative intensity values of maturing 89 soybeans H from lipids by microbiological 94 Hexane-defatted soy flours, odor and action 26 flavor scores of 88 potato chip-like Hungarian dry salami, free fatty acid problems in the usage of soybean 81 values of 105 oil and meal 2 Hydroperoxide ( s ) rancid breakdown of 5 of raw soybeans and peas, key com­ gg formation 69 pounds contributing to green .. to free radicals, breakdown of 69 scores linoleic acid 91 of hexane-defatted soy flours, lipid 71 88 odor and unsaturated fatty acid 90 with log of volatile components, regression analysis of soy­ 64 bean oil obtained by taste panels and Intensity values of maturing soybeans, direct GC analysis, com­ 89 flavor parison of oil 0 8

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

INDEX

119

J Jasmine

56

1 11

94-96 99 104 104 99

Microccus saprophyticus

Κ Ketone Ketones, methyl

Microbiological action on lipids Micrococci on pork fat, action of Milk fats Milk lipid oxidation Monoglycerides

94 70 1

L L. bulgaricus L. casei L. san francisco

96 110 96

Lactobacilli

104

Lactic acid bacteria

96

Ν Nonpolar compounds in three vegetable oils Nonpolar volatile components Nonvolatile decomposition products (NVDP) and minor constituents

49 47 45

Lactones 1,13 18 Light-induced oxidation 70 40 Linoleates 42 Linoleic acid(s) 3 component of soybean oil 3 hydroperoxides 9 Octane 49 Lipase(s) 24 activity 101 Odor character 9 from coconut oil, influence of tem­ and flavor scores of hexane-defatted perature on type of fatty acids soy flours 88 released by microbial 99 intensity 87 determination of specificity of microbial 100 Oil(s) by adjusted organoleptic score, specificity 100 ranking of 20 Lipid(s) blends 72 autoxidation of polyunsaturated .... 3 coconut 44-46 composition and structure 72 concentration of some volatiles in degradation 4 used frying shortening as com­ in foods, chemical changes involved pared to those in heated corn .. 54 in the oxidation of 68 corn 22,38,44,45 hydroperoxides 71 cottonseed 21,22 microbiological action on 94-96 and fat used for simulated deep-fat oxidation frying 20 factors affecting 72 flavor scores 64 milk 70 hydrogenated cottonseed 38 various flesh foods 74 influence of temperature on type of play in the positive and negative fatty acids released by micro­ flavors of food, role 1 bial lipases from coconut 99 Lipoxygenases, pea and soybean 91 linolenic acid component of soybean 3 nonpolar compounds in three M vegetable 47 peanut 22 M. caseolyticus Ill polar volatile compounds in three M. freudenreichii 101, 111 vegetable 48 M. varians Ill soluble vitamins, destruction of Meal, flavor problems in the usage of some 3 soybean oil and 81 soybean 23,44-46,62,63 Meat products 75 volatile compounds in corn 50 Mechanical deboning 77 volatileflavorconstituents produced Metal deactivators 83 by the interaction between the Methionine 26 food and the 21 Methyl carbinols 11 Methyl ketones 11 Oleic acids 3

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

LIPIDS AS A SOURCE O F FLAVOR

120 Organoleptic score, ranking of oils by adjusted Oxidation catalysts factors affecting lipid light-induced of lipids in foods, chemical changes involved in the milk lipid in variousfleshfoods, lipid Oxidative changes in sausages ( enzyme ) cyclization of polyun­ saturated fatty acids reactions Oxygen quencher Oxygen trapper

20 73 72 70 68 70 74 106 58 101 70 70

Ρ

Pea and soybean lipoxygenases Peanut oil Peas, key compounds contributing to greenflavorsof raw soybeans and

22 89 110

Pencillium roqueforti

Pentylfuran 49 Peroxide values of a fermented dry salami, free fatty acid values and 106 Photooxidation of unsaturated fatty esters, generation of aroma com­ pounds by 56 Polar components 49 Polar volatile components 46 Polar volatile compounds in three vegetable oils 48 Polyunsaturated fatty acids, oxidative (enzyme) cyclization of 58 Polyunsaturated lipids, autoxidation of 3 Pork fat, action of micrococci on 104 Potato chip-like flavor 26 Potatoes, deep-fat frying of 39 Poultry 77 99 100 101

Pseudomonas Ps. fragi Ps. ovalis

R Radicals, breakdown of hydro­ peroxides to free Rancid flavors Reaction products, secondary

69 2 71

S S. aureus Salami, free fatty acid values Salts

Sausage(s) 94 oxidative changes in 106 products 101 volatile fatty acids reported in dry .. 110 Secondary reaction products 71 Shortening as compared to those in heated corn oil (mg/kg), con­ centration of some volatiles in used frying 54 Silica gel 86 Soy flours, odor and flavor scores of hexane-defatted 88 Soybean flavor intensity values of maturing .. 89 lipoxygenases, pea and 91 meal, disposition of U.S 87 oil(s) 23,44-46,62,63 copper-hydrogenated 84 disposition of U.S 85 flavor scores with log of volatile linolenic acid component of and meal,flavorproblems in the usage of milestones in improving flavor stability of and peas, key compounds contribut­ ing to greenflavorsof raw Spoiling Stability of soybean oil, milestones in improving flavor Stale flavors Staphylococci Streptococcus thermophilus

Structure, lipid composition and Superoxide dismutase enzyme Sweetening agents

3 81 82 89 2 82 2 99 96

72 70 1

Τ

Taste panels and direct GC analysis, comparison of oilflavorscores obtained by 64 Temperature on type of fatty acids released by microbial lipases from coconut oil, influence of 99 Tocopherols 74 Toxicity 3 Triacetin 1 Tributyrin 1 Triglycerides 1,28 Trilinolein 38 Triolein 38 U

99,100 105,106 1

Unsaturated fatty ester, generation of aroma compounds by photooxida­ tion of

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

56

INDEX

121

Volatile(s) (continued) V flavor constituents ( V F C ) Vegacid 58 in deep-fat fried foods Vegetable aromas 60 originated from the food used for Vegetable oils 1 frying nonpolar compounds in three 47 produced by the interaction polar volatile compounds in three .. 48 between the food and the oil Vitamins, destruction of some oil in food products, instrumental soluble 3 analysis of Volatile(s) from frying fats: a comparative components study nonpolar 45 in used frying shortening as compolar 46 pared to those in heated corn regression analysis of soybean oil oil (mg/kg), concentration of flavor scores with log of 64 some compounds 53 in corn oil 50 W in three vegetable oils, polar 48 Weeds decomposition products 18,30-37,44 of frying, systematic identifica tion of the 2

In Lipids as a Source of Flavor; Supran, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

19 21 21 60 42

54

56