Chapter 3
Performance of Vanilla Flavor in Low-Fat Ice Cream 1
Ernst Graf and Kris B. de Roos
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1Flavor Frontier, 731 Wright Street, Rathdrum, ID 83858 Tastemaker, Nijverheidsweg 60, 3771 M E Barneveld, Holland
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2
Fat removal from vanilla ice cream results in drastic flavor profile distortion and loss in vanillin intensity during storage. The chemical instability of low-fat ice cream results from both chemical reactions and physical interactions with proteins, starches and other hydrocolloids. Initial flavor perception, however, depends primarily on phase partitioning of the individual chemical components between water and oil. A nonequilibrium partition model was developed to accurately predict flavor performance in foods and beverages. The proposed physicochemical model describes the effect of fat level on the flavor profile and it calculates a reformulation factor for each chemical component of a compounded flavor to restore the original taste in a reduced fat product. It also allowed for the design of a novel cryogenic fat enrobement technology for a vanilla extract that cannot be reformulated. In this case we created a microenvironment for the flavor that mimics high-fat ice cream.
Consumer preoccupation with excess dietary fat has been steadily rising over the past decade (7). In 1993 the percent rating factor as greatest concern with fat content reached 54% and was exactly twice that for salt or cholesterol levels. A steady growth in low- or no-fat food products clearly reflects this consumer health awareness. Find/SVP pegs the US market for low-fat and/or low-cholesterol prepared foods at $15.7 billion in 1992, $23.5 billion in 1993, and forecasts $44.9 billion by 1997 (2). Of the 12893 new food products introduced in 1993, the low-fat segment scored a total of 577 or 4.4%. Despite the widespread interest in total calorie reduction and fat removal, many consumers exhibit fairly sporadic purchasing behavior (3). The gap between actual eating patterns and the marked concern with healthy food arises primarily from the compromise in flavor of low-fat foods. In a recent survey of the relative
0097-6156/96/0633-0024$15.00/0 © 1996 American Chemical Society
McGorrin and Leland; Flavor-Food Interactions ACS Symposium Series; American Chemical Society: Washington, DC, 1996.
Downloaded by FUDAN UNIV on November 28, 2016 | http://pubs.acs.org Publication Date: May 5, 1996 | doi: 10.1021/bk-1996-0633.ch003
3. GRAF & DE ROOS
Vanilla Flavor in Low-Fat Ice Cream
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importance of five product attributes, shoppers ranked taste clearly above nutrition, price, product safety and storability. In the preface to Food Technology's 1994 top ten food trends (4) the author concluded that taste alone will reign as the most powerful criterion for food selection. Demographic changes and increasing affluence in Western societies have resulted in a growing consumer demand for healthy food of outstanding quality. The significance of taste holds particularly true for the frozen dessert market. However, several sensory studies have demonstrated that the flavor of no-fat or calorie-reduced ice creams are unable to match their full fat analogs. The development of premium low-fat ice cream poses a serious technological challenge but also a competitive business opportunity to the sophisticated flavor chemist. Calorie reduction in vanilla ice cream results not only in a rapid loss in vanillin intensity during storage, but also in drastic initial flavor profile distortion. The altered flavor performance in a fat-free or low-fat ice cream containing a natural Bourbon vanilla extract manifests itself in an unbalanced taste with phenolic, charcoal off-notes, lacking creaminess and mouthfeel, exhibiting no lingering sensation and displaying poor overall taste acceptability. This chapter first reviews the chemical and physical factors contributing to the instability of vanilla flavor in low-fat ice cream and then presents a rigorous physicochemical mathematical model describing initial flavor performance. This nonequilibrium phase partition model accurately predicts the effects of fat on the vanilla flavor profile in ice cream. It also allows for the calculation of a reformulation factor for each chemical component of a compounded flavor to restore the original aroma and taste in a reduced fat product. Furthermore, the partition model enabled the design of a novel cryogenic fat enrobement technology for the vanilla extract since it cannot be reformulated. In this case we created a microenvironment for the flavor that mimics high fat ice cream. Materials and Methods Materials. A l l chemicals used in this study were of analytical grade. Food ingredients were purchased from suitable suppliers in Holland, Germany or the United States. Determination of Partition Coefficients. Both water-to-air and oil-to-air partition coefficients were determined at 25°C using capillary tubes packed with XAD-4 beads according to the method of Etzweiler et al. (5). Determination of Lactoperoxidase. Milk was subjected to various heat treatments and then used for the preparation of vanillin-containing custard. Residual lactoperoxidase activity in the custard was quantitated by determining the enzymatic oxidative conversion of added vanillin to vanillic acid. The custard (1.0 mL) was diluted with water (5.0 mL) and homogenized in an ultrasonic bath. Vanillin and vanillic acid were extracted with acetonitrile, separated from the precipitate by subsequent centrifugation and filtration, and analyzed by reverse-phase HPLC on a CI8 column. The compounds were eluted with a solution of acetic acid and sodium
McGorrin and Leland; Flavor-Food Interactions ACS Symposium Series; American Chemical Society: Washington, DC, 1996.
F L A V O R - F O O D INTERACTIONS
Table I. Ingredient Composition of Vanilla Ice Cream
Ingredient
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Heavy cream (36% fat) Milk (2% fat) Sugar Na-CMC Vanilla extract Guar gum Salt Carrageenan
Low-Fat Ice Cream (2% Fat)
High-Fat Ice Cream (15% Fat)
1.40% 82.10% 14.00% 2.00% 0.25% 0.10% 0.08% 0.07%
39.09% 44.41% 14.00% 2.00% 0.25% 0.10% 0.08% 0.07%
CHO
Figure 1. Structure of vanillin.
Table II. Enzymatic Oxidation of Vanillin Heat Treatment of Milk
75°C 80°C 85°C
Lactoperoxidase Activity in Heat-Treated Milk
6.1 U/ml
