Bitter flavour

Rye will grow under much harsher conditions than wheat. In Germany and Scandinavia rye breads, either wholly rye or mixed with other grains, are eaten. In the UK, rye is little used and the somewhat bitter flavour that it imparts is in general not appreciated. The small amount of rye used is deployed in health food products, crisp breads and in making rye products to satisfy foreign tastes. 

Cappuccino coffee is named after Marco d Aviano, a Capuchin monk who was recently made a saint. He entered a looted Turkish army camp, and found sacks of roasted coffee beans. He mixed it with milk and honey to moderate its bitter flavour. 

We see how solvated protons impart the subjective impression of a sour, bitter flavour to the ethanoic acid in vinegar. In fact, not only the sour flavour, but also the majority of the properties we typically associate with an acid (see Table 6.1) can be attributed to an acidic material forming one or more solvated protons H+(aq) in solution. 

Erydman, A. et al.. Citrus fruit bitter flavours isolation and functional characterization of the gene Cml,2RhaT encoding a 1,2 rhamnosyltransferase, a key enzyme in the biosynthesis of the bitter flavonoids of citrus. Plant J., 40, 88, 2004. 

Garm, O., Lunaas, T. and Velle, W. 1963. The causes of bitter flavour in milk. Meieripos-ten 52, 253-258. 

Main actives Sesquiterpene lactones, which are bitter flavoured, triterpenes, steroids, flavonoids, mucilages and an inulin content that varies from 2 to 40% in the autumn. Benefits The bitter components were used to promote the flow of digestive juices in the upper intestinal tract. 

The complete examination for these bitter substances is long and complicated and does not always give certain results reference may be made to special publications on the subject. A short test, which is sufficient in many cases, is as follows 100 c.c. of the beer are evaporated to about one-half the volume, basic lead acetate being then added until no further precipitation occurs. The liquid is next filtered and the excess of lead in the filtrate precipitated with ammonium sulphate. If, after being again filtered, the liquid has a distinctly bitter flavour, the presence of extraneous bitter substances is indicated. 

The palatability of safflower meal to poultry tends to be low (Ravindran and Blair, 1992) due to the presence of two phenolic glucosides matairesinol-p-glucoside, which imparts a bitter flavour, and 2-hydroxyarctiin-p-glucoside, which also has a bitter flavour and has cathartic properties (Darroch, 1990). Both glucosides are associated with the protein fraction of the meal, and they can be removed by extraction with water or methanol, or by the addition of P-glucosidase. 

Among the seed spices, cumin fruits have a distinctive bitter flavour and strong,... 

The essential oil content of cumin seed ranges from 2.3 to 5.0%. Cumin fruits have a distinctive bitter flavour and a strong, warm aroma due to their abundant essential oil content. Of this, 40-65% is cuminaldehyde (4-isopropylbenzaldehyde), the major constituent and important aroma compound, and also the bitterness compound reported in cumin (Hirasa and Takemasa, 1998). The odour is best described as penetrating, irritating, fatty, overpowering, curry-like, heavy, spicy, warm and persistent, even after drying out (Farrell, 1985.) The characteristic flavour of cumin is probably due to dihydrocuminaldehyde and monoterpenes (Weiss, 2002). 

Flavouring substances that cause only taste impressions are defined as substances that are usually non-volatile at room temperature. Therefore, they are only perceived by the taste receptors [7]. Examples are sucrose (sweet) or caffeine (bitter). Flavouring substances causing odour impressions are volatiles that are perceived by the odour receptors [7]. Examples are ethyl butyrate or dimethyl sulfide. Some flavouring substances are perceived by taste and odour receptors (e.g. acetic acid, butyric acid). 

The production of bitter flavours generally is attributed to the formation of bitter peptides. Bitter flavour results when the peptides are formed faster than they can be broken down by the proteases and peptidase of the starter cultures. 

Lemieux, L., and Simard, R. E. (1991). Bitter flavour in dairy products. I. A review of the factors likely to influence its development, mainly in cheese manufacture. Lait 71,599-636. Lemieux, L., and Simard, R. E. (1992). Bitter flavour in dairy products. II. A review of bitter peptides from the caseins Their formation, isolation and identification, structure masking and inhibition. Lait 72, 335-382. 

Stadhouders, J., and Hup, G. (1975). Factors affecting bitter flavour in Gouda cheese. Neth. Milk Dairy J. 29, 335-353. 

Visser, S., Hup, G., Exterkate, F. A., and Stadhouders, J. (1983). Bitter flavour 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. 

It is known that increasing the pH of beer produces a coarser bitter flavour so it follows that the undissociated iso-a-acids have a finer bitter flavour than the dissociated anion. Thus, Rigby [106] has proposed that there is a similar... 

Flavouring ingredient, alcohol denaturant. Cryst. with intensely bitter flavour. Mp 84° (69°). [a]o +59.6 (CHCI3). 

Bitter flavours can be improved with flavourings with a pleasant bitter taste, probably in addition with sweet flavourings, for example chocolateA anilla. 

Sweet flavours can be improved with peppermint, probably in combination with sour or bitter flavours. Corrigents that suggest a sweet taste by smell or colour can be added, such as vanilla and fruits. 

Dried spent hops are a fibrous product and comparable to poor hay in nutritive value, but they are less palatable, probably because of their bitter flavour. This product is rarely used as a food for animals today, most of it being sold for use as fertiliser. 

Termination reactions may lead to the formation of both high and low molecular weight products of the peroxidation reactions. Depending on the lipid, some of the low molecular mass compounds may be important flavours (or aromas) of foods (section 5.2.3). For example, short to medium chain aldehydes formed from unsaturated fatty acids may give rise to rancidity and bitter flavours on the one hand or more pleasant attributes such as those associated with fresh green leaves, oranges or cucumbers on... 

---