Flavors bitter

In general, many species of algae have cell walls resistant to digestive enzymes, dark colors, and bitter flavor. AH of these characteristics must be altered to make an acceptable food or feed product. 

The quahty of individual gums is mainly deterrnined by color and taste or odor. Many gums are colorless when secreted, but darken on aging. Most gums are usually tasteless unless contaminated by the bitter flavors of tannins which precludes their use in foods. 

The chaff, which is the bean silverskin caught in the fold of the bean, flies off the bean during roasting and can be collected, pelletized, and mixed with roasted beans which are to be ground, even though it may impart a bitter flavor to the final beverage. 

Methods for the decaffeination of green coffee beans, mainly with solvents after a steaming, have already been described. Even with the selective adsorption techniques to remove only caffeine, it is unlikely that the full character of the starting beans can be realized in a final decaffeinated beverage the result is that Robusta coffees are generally used to prepare decaffeinated coffee. The cost is kept down and the treatment, anyway, reduces any harsh or bitter flavor that the Robusta coffee may have had. The resulting beverage will be relatively caffeine-free, but Robusta coffee will contribute more soluble carbohydrates, phenols, and volatile fatty acids, and much less of the diterpenes found in Arabica coffees. 

Soy Protein Concentrates. Both non-functional (low or no solubility) and functional (good solubility, emulsification capacity, and dispersibility) soy protein concentrates (70% protein, dry basis) are commercially available for use in meat products (2-4, 6, j), 15) Normally, a highly functional product with no harsh or bitter flavors is desirable. When used to replace lean meat, non-hydrated concentrate can be used at levels up to 6-7% in finished nonspecific emulsion meats Higher replacement levels or formulas with specific cost/nutrition requirements may use soy protein concentrate with a judicious amount of textured soy protein (6). Excellent yields, cost savings, texture, flavor and nutrient profiles are possible. However, most soy protein concentrates lack sufficient solubility or sufficiently low viscosities to be used in brines for absorption or injection into whole muscle tissue. When legal standards for protein content exist (13), more concentrate must be used to achieve legal minimums. Brine viscosities increase and uniform distribution of brine components throughout the specific whole muscle piece is restricted. Finished product appearance and flavor are easily compromised. Thus, use of soy protein concentrates in whole muscle applications is limited. 

Frydman A, Weisshaus O, Bar-Peled M, Huhman D, Summer L, Matin F, Lewinsohn E, Fluhr R, Gressel J, Eyal Y (2004) Citrus fruit bitter flavors isolation and functional characterization of the gene Cml,2RhaT encoding a 1,2rhamnosyltransferase, a key enzyme in the biosynthesis of the bitter flavonoids of Citrus. Plant J 40 88-100... 

Puspitasari, N. L., Lee, K., and Greger, J. L. (1991). Calcium fortification of cottage cheese with hydrocolloid control of bitter flavor defects. /. Dairy Sci. 74,1-7. 

The seed oil is golden yellow, with a nutty odor and a pleasant, although slightly bitter flavor, and has been described as similar to almond oil in consistency and taste (van der Maesen, 2006). 

Hexamethylenetetramine and cyclohexylamine are both tasteless solutions. Hexamethylenetetramine, a highly water soluble compound, is tasteless even diough it is compost of a AH-X component (Figure 1). Its molecular size is too small to exhibit the bitter taste proposed by the theory presented in Figure 1. Cyclohexamine, similarly, is tasteless. When both solutions are mixed together, a bitter flavor is exhibited. Interestingly, the bitter flavor of the mixed components is changed to sweet when acetic acid is adde (5), a fact consistent with the competitive theory. 

Many enzymes extracted from higher plants have been tried for clotting cheese milk (Burnett 1976), however, attempts to use them have been unsuccessful. Most plant proteases are strongly proteolytic and cause extensive digestion of the curd, which has resulted in reduced yields, bitter flavors, and pasty-bodied cheese. 

Visser, S., Hup, G., Exterkate, F. A. and Stadhouders, J. 1983. Bitter flavor in cheese. 2. Model studies on the formation and degradation of bitter peptides by proteolytic enzymes from calf rennet, starter cells and starter cell fractions. Neth. Milk Dairy J. 37, 169-180. 

Otagiri et al. (22) used model peptides composed of arginine, proline, and phenylalanine to ascertain the relationship between bitter flavor and chemical structure. They reported that the presence of the hydrophobic amino acid at the C terminus and the basic amino acid at the N terminus brought about an increase in the bitterness of di- and tripeptides. They further noted a strong bitter taste when arginine was located next to proline and a synergistic effect in the peptides (Arg)r(Pro) ,-(Phe) (/ = 1,2 m, n = 1, 3) as the number of amino acids increased. Birch and Kemp (23) related the apparent specific volume of amino acids to taste. 

Glycyrrhizin is 50-100 times sweeter than sucrose and has a slow onset of taste and a long aftertaste (Table 1). It exhibits a dark, sweet, woody flavor, which limits its use as a pure sweetener. Glycyrrhizin provides licorice flavor, enhances food flavors, masks bitter flavors, and increases the perceived sweetness level of sucrose. It also has the potential for providing functional characteristics, including foaming, viscosity control, gel formation, and possibly antioxidant characteristics (3,19,58). 

As a category of alkaloids with distinctive bioactivity, methylxanthine derivatives have in recent years received increasing attention in the food and pharmaceutical industries. The most important compounds of this class, characterized by a bitter flavor, are caffeine CF, theobromine TB, and theophylline TP (Fig. 6). 

Fresh Citrus Juice. Freshly extracted commercial orange juice may contain a high peel oil content making sensory evaluation of this product very difficult because of the overriding, biting and even bitter flavor effect of the peel oil. This is one of the reasons why in certain plants, minimal attention is paid to the flavor quality of the juice until the product is standardized either in retail or bulk form (2). 

Cornflower (Centaurea cyanus L.) honey is greenish yellow, with an aroma reminiscent of almonds and a peculiar, slightly bitter flavor. 

Tobacco (Nicotiana tabacum L.) honey ranges in color from light to dark, has an unpleasant aroma and a bitter flavor. 

The herbs and spices may be placed in cloth bags and suspended in the wine. After the first extraction, fresh base wine may be added for a second, and even a third extraction. Partial extractions are preferred, as complete extraction may result in the incorporation of undesirable flavors or aromas. This also avoids pressing the spent materials that is associated with the release of objectionable bitter flavors. 

Unstabilized bran and polish have been used almost exclusively for animal feed, due to the bitter flavor that develops from the lipolytic action of enzymes on the oil found in them. However, development of a thermal process that inactivates the lipases has resulted in a stabilized rice bran product that is suitable for the food industry. The impressive nutritional qualities of the oil, fiber, carbohydrate and proteins of rice bran have made it a valuable food material. Removal of fiber from the bran by physical K,J7or enzymic1819 processes produces a milk-like product having desirable nutritional and functional properties. The nutritional composition of the rice bran milk product described by California Natural Products has been shown to match the nutritional requirements of an infant formula. Originally, the anti-nutritional factor of the residual phytates was of concern. However, as of 2005, phytase enzymes are suitable for use to break down these phytates. 

Limonin and naringen, which can give citrus juices an undesirable bitter flavor, can be removed selectively by passing juice through a crosslinked polymer of (3-cyclodextrin.87,88 Only the bitter components are removed. The polymer can be regenerated for reuse by washing the polymer with a 1-2% solution of sodium hydroxide. 

Chymosin produces cheese free of bitter flavor and of excellent texture. The use of other acid proteases such as pepsin and many of the microbial rennets in the coagulation step often leads to bitter flavor and a soft texture after ripening. 

Partial proteolysis has been used by several researchers to improve functional properties, i.e. foaming, solubility of proteins (7,8,9). The significant problems associated with enzyme hydrolysis of proteins are excessive hydrolysis occurring under batch conditions, the generation of bitter flavors during hydrolysis and the cost of enzymes. Extensive information on factors affecting proteolysis of proteins and the problem of bitterness has been reviewed by Fujimaki et al. (7) in conjunction with studies of the plastein reaction. 

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