Organoleptic

Oxidation begins with the breakdown of hydroperoxides and the formation of free radicals. These reactive peroxy radicals initiate a chain reaction that propagates the breakdown of hydroperoxides into aldehydes (qv), ketones (qv), alcohols, and hydrocarbons (qv). These breakdown products make an oxidized product organoleptically unacceptable. Antioxidants work by donating a hydrogen atom to the reactive peroxide radical, ending the chain reaction (17). 

Quality Control. Reproducible production of perfumes requires careful quality control of all materials used as well as the compounding process itself. The use of analytical tools has iacreased over the years with their availability, but there can be no substitute for organoleptic evaluation. The human nose is far more sensitive than any analytical instmment for certain materials, yet it is also quite limited as a quantitative tool and is subject to fatigue. There are also weU-documented examples of specific anosmias ia iadividuals, ie, iaability to smell certain odor types, which is somewhat analogous to color-blindness. 

Spontaneous fermentations are used for wine production in Erance, some other European countries and in South America. In recent years, smaller California wineries have begun experimentation with spontaneous fermentations as well. They generally start more slowly than fermentations inoculated with commercial dried yeast, are more difficult to control, and may suffer from growth of undesirable contaminants. However, it is claimed that the resulting wines possess better organoleptic properties, particularly more complex flavor and aroma. 

The function of Jisper Uis fermentation appears to be primarily the breakdown of protein and polysaccharides by secreted proteases and amylases. Replacement oiPispergillis by chemical or enzymatic hydrolysis has no major impact on the organoleptic properties of the sauce. Likewise, inoculation with a pure culture of Ixictobacillus delbrueckii to carry out the acetic acid fermentation produces a normal product. The S. rouxii and Toru/opsis yeasts, however, are specifically required for proper flavor development. 

The temperature and extract content must be controUed regularly. Two weeks before bottling the beer should have a carbon dioxide content of 0.50 wt %, and samples are often taken for organoleptic tests. 

Filtering. Conditioning or 1 agering gives the beer its desired organoleptic properties, but it stiU contains yeast, protein-tannin complexes, etc, ie, it has a hazy appearance. A high quaHty beer must be clear and totaUy sterile, have coUoidal stabiHty, and yeast must be removed to aUow the beer to have biological stabiHty. The protein-tannin complexes must also be removed so as not to upset the coUoidal stabiHty. 

Com symp soflds are also dry products, have a smaller average size, and are comparatively sweeter (12). Both maltodextrins and com symp soflds are used to prevent caking enhance dispersibiUty and solubiUty provide body or bulk impart deskable texture bind, carry, and protect flavors control extmsion expansion provide viscosity form films and coatings provide an oxygen barrier inhibit crystallization control sweetness improve sheen improve organoleptic characteristics slow meltdown and improve freeze—thaw stabiUty. 

Sweeteners. The sweeteners (qv) used in carbonated beverages may be either nutritive or noimutritive. The quaUty of the sweetener is one of the most important parameters affecting the overall quaUty of the beverage. Organoleptic profile (taste and odor), solubiUty, microbial stabiUty, and temperature stabiUty are important quaUty parameters. 

It is generally claimed that metallocene polyethylenes (often abbreviated to m-PE) exhibit superior mechanical and optical properties as well as better organoleptic properties (resulting from the lower residue levels). As an example m-LLDPE is particularly favoured as a stretch film for wrapping because of the good prestretchability, high puncture resistance and tear strength, all of which are claimed to be better than with conventional LLDPE. 

Organoleptic A material that influences a sensory organ, as in the perception of odor by the human nose. 

Figure 3.6 Two-dimensional gas chromatogram of an oi ange oil extract, in which a 2 s heait-cut has been made in the region A where /3-miycene has eluted on a non-polar column. Secondary analysis on a polar Carbowax 20 M column indicated two compounds (marked B and C), both identified as odoi ous by organoleptic assessment. Reproduced from R A. Rodriguez and C. L. Eddy, ]. Chromatogr Sci. 1986, 24, 18 (32).

In order to use any of the results obtained by objective methods as the basis for the acceptance or rejection of a product, there must be available reliable information as to the relationship between the values obtained and organoleptic quality in terms of consumer acceptance and utility. Where standards are based upon measurement of such labile constituents as ascorbic acid or sugar, a knowledge of the normal values for good commercial practice is necessary. Such values have not yet been adequately established. This should constitute a useful field for research of inestimable value to the industry. 

Such definitions imply that there is a reliable test for rancidity, but this is not the case. The difficulties are centered about the fact that in the final analysis, rancidity must be detected through organoleptic observation, which is subject to all the weaknesses inherent in a test involving personal judgment. As was pointed out in a recent discussion (S), these weaknesses include variabilities in the taste and odor sensitivities of persons in the same or different laboratories, their previous taste experiences, the prevailing condi-... 

A common method for determining the stability of pastry, potato chips, and the like is to place a number of broken pieces of the product in 4-ounce mayonnaise jars with screw tops and store them at room temperature or in the Schaal oven in the absence of light. At regular intervals samples are removed and tested for peroxide content and organoleptic rancidity. 

Because the quality and health aspects of foods cannot be measured by a single index, it necessarily follows that the subject of control methods in the canned food industry is very broad, and includes chemical, physical, organoleptic, and bacteriological tests, only the first of which is discussed here. The measurement of color, odor, optical clarity, texture, viscosity, and chemical composition has been used to evaluate canned foods, but in many cases the methods that are applicable to one product are either not applicable to another, or can be used only after considerable modification. 

For us to remain perfectly healthy, the protein in our diet must supply suffident quantities of amino acids. We prefer to eat our protein in particular forms, that is in foods having particular textures, tastes and smells (these are called organoleptic properties). Conventional sources of protein are plants, mainly as cereals and pulses, and animals, mainly as meat, eggs and milk. The proportions of such proteins eaten in various parts of the world differ widely (Figure 4.1). 

What are they like to eat Humans are particular about the organoleptic properties of their food. Microbial cells may have little taste or smell, or even smell or taste unpleasantly to some people. The texture may not be the same as in conventional foods, particularly with unicellular organisms. These draw-backs can be overcome by adding a proportion of SCP to manufactured foods. However, even when SCP is incorporated into manufactured foods it may not have suitable characteristics such as stability, ability to bind water or fats, or ability to form gels, emulsions or foams. SCP for feed does not have to meet such strict requirements. 

Random copolymers of acrylonitrile and styrene containing less than 30% AN have been well known (11), and many varieties have been sold commercially. The generic material known as SAN, which is a copolymer of 25% AN and 75% styrene, has been sold for many years but has not been used in food or beverage packaging because of its relatively poor barrier and organoleptic properties. There was little or no interest in... 

When these AN/S copolymers, are manufactured into Lopac containers, they remain essentially unmodified and in their pure state. Many of the desirable barrier and organoleptic properties of the containers can be attributed to the fact that no plasticizers, rubber, or other common modifiers are incorporated. 

Chaib, J. et al., Stability over genetic backgrounds, generations and years of quantitative trait locus (QTLs) for organoleptic quality in tomato, Theoret. Appl. Genet. 112, 934, 2006. 

---