Consumption of flavonoid-rich foods and increased plasma antioxidant capacity in humans: cause, consequence, or epiphenomenon?

https://dro.deakin.edu.au/eserv/DU:30004132/keast-anoverviewofbinary-2003.pdf

An overview of binary taste–taste interactions

Publisher Summary This chapter discusses the selection of food by rats, humans, and other animals, and focuses on the complex problems, especially in food recognition and choice, in the omnivores or generalists. Food selection implies food ingestion. Food ingestion implies the presence of food. Therefore, background for the study of food selection includes the food search process: search images and search mechanisms for finding appropriate food stimuli in the environment. Honey bees provide fine examples of a highly developed food search system. Food selection also implies the ability to obtain or capture food, and to assimilate it, for which many often exotic mechanisms have been evolved. Given the presence of potential food, ingestion then usually depends on an internal state or detector indicating a “need” for the particular food or class of foods, and recognition of the potential food as food. Omnivores, such as rats and humans, faced with an enormous number of potential foods, must choose wisely. They are always in danger of eating something harmful or eating too much of a good thing. Although there are some helpful internal mechanisms, such as poison detoxification, nutrient biosynthesis, and nutrient storage, the major share of the burden for maintaining nutritional balance must out of necessity come from incorporation of appropriate nutrients in the environment and, hence, behavior. The most striking parallel between human and rat feeding is in the neophobia seen in both. The chapter discusses the multiple determinants of food selection in man that are divided into biological factors and effects of individual experience, on one hand, and cultural influences, on the other.

The Selection of Foods by Rats, Humans, and Other Animals

THE molecular feature common to the many different sweet tasting compounds has been sought for many years1. For the sugars, it was proposed2–5 that the sweet unit is the glycol group, and that intensity of sweetness varied inversely with the degree to which glycol OH groups appear to be intramolecularly hydrogen bonded. It is now apparent that vicinal OH groups in the glycol unit need to be approximately gauche, or in a staggered conformation. Vicinal OH groups which are in the anti conformation apparently are too far apart to cause sweet taste. Glycol OH groups which are eclipsed probably participate in an intramolecular hydrogen bond which competitively inhibits interaction of glycol with the receptor site. These steric features of sweet and non-sweet sugar glycol units are shown in perspective in Fig. 1. Glycol conformational parameters, and the gross conformation of pyranose and furanose rings, have been used to explain the varying sweetness of the sugars2–5.

Molecular Theory of Sweet Taste

Biorefineries for the production of top building block chemicals and their derivatives.

IN an attempt to identify the feature common to various and seemingly unrelated compounds which taste sweet, we suggested1 that the saporous unit of all sweet tasting compounds was a bifunctional group consisting of an acidic (AH) and a basic (B) moiety with an A—H proton to B distance of about 3 A. The common unit described seems to be very similar to that proposed by Warfield2, in which the common molecular feature was visualized as a “taste couple” composed of a proton and a neighbouring, unshared electron pair.

Sweet taste of D and L-sugars and amino-acids and the steric nature of their chemo-receptor site.

The glucose, fructose, sucrose, and sorbitol content of apple, pear, plum, cherry, grape, strawberry, raspberry, blackberry, and peak fruit was compiled from the literature; their range, mean, standard deviation, and percent coefficient of variance were calculated. The individual fruits have characteristic patterns relating to their sorbitol content, glucose: fructose ratio, and sucrose content which are influenced to only a small degree by variety, season, or geographic origin. Processing in many cases has a marked effect on sucrose content.

Free sugars and sorbitol in fruits--a complication from the literature.

In presenting the material in this chapter, four fundamental propositions are made. These are: (1) Sucrose (sugar) tastes sweet. (2) Quinine tastes bitter. (3) Sodium chloride tastes salty 1. (4) Hydrochloric acid tastes sour.

R.S. Shallenberger

Papers

Molecular Theory of Sweet Taste

Sweet taste of D and L-sugars and amino-acids and the steric nature of their chemo-receptor site.

Free sugars and sorbitol in fruits--a complication from the literature.

Chemical Structure of Compounds and Their Sweet and Bitter Taste

Relative stability of glucose and fructose at different acid pH