Effect on flavor

Most of the bacteria, yeasts, molds, and higher fungi of interest for SCP production are deficient in methionine and must be supplemented with this amino acid to be suitable for animal feeding or human food appHcations. Also, lysine—arginine ratios should be adjusted in poultry rations in which yeast SCP is used (62). Human feeding studies have shown that only limited quantities of yeast such as Candida utilis can be added to food products without adverse effects on flavor (63). 

Diacetyl, acetoin, and diketones form during fermentation. Diacetyl has a pronounced effect on flavor, with a threshold of perception of 0.1—0.2 ppm at 0.45 ppm it produces a cheesy flavor. U.S. lager beer has a very mild flavor and generally has lower concentrations of diacetyl than ale. Diacetyl probably forms from the decarboxylation of a-ethyl acetolactate to acetoin and consequent oxidation of acetoin to diacetyl. The yeast enzyme diacetyl reductase can kreversibly reduce diacetyl to acetoin. Aldehyde concentrations are usually 10—20 ppm. Thek effects on flavor must be minor, since the perception threshold is about 25 ppm. 

Analytical Data Analysis. The development and commercialization of the gas chromatograph in the mid 1950 s had a dramatic effect on flavor research because the technique made it possible to obtain objective measurements of the numerous compounds which made up the flavor of the product under investigation. Data analysis was reasonably simple and straightforward, as the number of resolved peaks was small. However, as chromatographic techniques were refined and high resolution capillary columns and microprocessor controlled GC s were introduced, the use of computers and multivariate analysis techniques have become essential for data analysis and reduction. 

Figure 1. Transitions in dried materials and their effect on flavor release.

Air classification, starch isolation, 674-675 Aldehydes, see also Carbonyl compounds citrus oils, quantification meats, effect on flavor, 559 Alditol acetates... 

The cooling rate showed no appreciable effect on flavor scores and was eliminated as a variable in subsequent tests. Since there was some indication of a tendency toward texture deterioration on rapid cooling, a standard method of cooling to 4°C. followed by vapor phase cooling (essentially slow) to irradiation temperature was followed in subsequent studies designed to measure the effects of the other variables more accurately. 

Testing of Potentially Hazardous Compounds. A possible danger exists in testing the effect on flavor of federally non-cleared substances that may enter into citrus products. A sensory evaluation supervisor has a clear obligation to refrain from allowing unknown potentially hazardous substances in his or her research. 

A. Kobayashi, Sotolon Identification, formation, and effects on flavor, in Flavor Chemistry Trends and Developments, R. Teranishi, R. G. Buttery, and F. Shahidi (eds),... 

Random-coil polysaccharides make strong films, because they are given to a high incidence of long-life contact points for the same reason, they are good carriers of flavor. Notably, concentration had no effect on flavor release from a nongelling xanthan dispersion (Baines and Morris, 1988). 

The methods involving fat separation, of which the Bureau of Dairy Industries (BDI) methods are most common, measure only fat-soluble FFAs and hence underestimate the total FFA level (Deeth et al., 1975 Van Crombrugge et al., 1982). For milk, this is of little consequence as the level of the long-chain acids correlates highly with that of the short-chain acids responsible for the flavor. In products such as butter, measurement of fat-soluble FFAs only will not detect small increases in FFA postmanufacture which can have a detrimental effect on flavor due to the short-chain FFAs present (Deeth et al., 1979). 

Dimick, P.S. 1982. Photochemical effects on flavor and nutrients of fluid milk. Can. Inst. Food Sci. Technol. J. 15, 247-256. 

Finally, aldehydes can react with nitrogen (31-32) and sulfur nucleophiles, including H2S, which may also be present in wines. These reactions may have dramatic effects on flavor and aroma (e.g., formation of ethyl mercaptan from acetaldehyde and H2S results in formation of a onion-like or burnt rubber aroma) and will decrease the levels of free aldehydes which can be readily quantitated (1). 

Prime concerns in storage of crude and once-refined soybean oils include increases in moisture and volatile matter, color after refining or bleaching, peroxide value, free fatty acids, and refining losses. Aside from possible effects on flavor and oxidative stability, many of these quality factors also affect the commercial value of oil in trading channels. With the exception of peroxide values and refined color, the other quality factors above are written into specifications for oils sold under trading rules of the National Soybean Processors Association (NSPA) (67). 

C) (12) The other preservatives were either ineffective or had detrimental effects on flavor, texture, or appearance. Citrus salads were treated with sodium benzoate or potassium sorbate (12). No extension of shelf life was observed when these chemicals were added at storage temperatures of 50°F and 40°F, but when the additives were present at 30°F storage substantial improvements in shelf life were observed, demonstrating the synergistic effect of chemical additives and low temperature storage. 

Jia, M., Zhang, Q.H., and Min, D.B. 1999. Pulsed electric field processing effects on flavor compounds and microorganisms of orange juice. Food Chemistry 65 445 51. 

Before the advent of UF, juice precessors hydrolyzed cloud-stabilizing polysaccharides such as pectin and starch with pectinase, coagulated with gelatin, and then clarified the cloudy cider with a diatomaceous earth filter. The materials collected on the filter provided an ideal substrate on which to grow and multiply bacteria. This resulted in high microbial counts in the juice, but high temperature pasteurization is not desirable because of its effect on flavor. 

Flavor properties of proteins are critical in food applications. Frequently, products with the same or equal functionality will not be chosen for use by food manufacturers because of their effect on flavor. This includes not only off-flavors associated with the protein but also the binding of added flavors by the protein, thus reducing the impact of the added flavor. Flavor binding by food proteins has been reviewed by Jasinski and Kilara [99] and Kinsella [100]. 

Reactions Essentially Involving Tannins and their Effects on Flavor... 

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