Proteins anti-nutritive

Complete removal of procyanidin is not necessary to overcome anti-nutritional effects. Removal of most procyanidin or addition of sufficient protein will overcome anti-nutritional effects of procyanidins. Small concentrations of procyanidin can be easily overcome by adding protein. 

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. 

Interactions between tannins and proteins have been extensively studied (Hager-man 1989 Haslam and Lilley 1988 Haslam et al. 1992), owing to their role in haze formation, astringency perception, and nutritional and anti-nutritional effects resulting from inhibition of various enzymes and reduction of dietary protein digestion. Other effects include reduced adsorption of /3-casein at the air-liquid interface in the presence of epigallocatechin gallate with potential consequences on foam properties (Sausse et al. 2003). 

Tamarind seed is a by-product of the tamarind pulp industry. Presence of tannins and other dyeing matters in the seed testa make the whole seed unsuitable for consumption, but they become edible after soaking and boiling in water. Tamarind seed is also used as raw material in the manufacture of polysaccharide (jellose), adhesive and tannin. Seeds and kernels are high in protein content, while the seed coat is rich in fiber and tannins (anti-nutritional factors). Seeds are gaining importance as an alternative source of proteins, and are besides a good source of fatty acids and rich in some essential minerals, such as Ca, P, Mg and K. 

Shaker screens, aspirators, and/or gravity tables may be used to separate the hulls from the meats. Hulls should be larger in size, lower in density, and thus are more buoyant in an air stream than the oil-rich meat and are easily removed by cascade aspirators. The hulls-rich stream may then be sent to shaker screens and/or gravity tables to remove any small meat particles that were aspirated with the hulls. The recovered meat particles are recycled back to the dehulled meats stream to minimize oil and protein losses. The hulls may be heat-treated to inactivate anti-nutritional factors... 

In addition to the nutritional and physiological effects of Maillard browned protein as described in the previous section, it has been shown that the reduced nutritional value of the brown products does not seem to be limited to the loss of amino acids, since supplementation of the diet with those amino acids could not completely restore its biological value (15). This suggests the possible formation of some inhibitory or anti-nutritional compounds during the Maillard reaction, the presence of which cannot be detected with short-term nutritional feeding assays. Moreover, the short-term feeding effects reported in the literature (30) seem to be due in part to nutritional deficiency and not specifically the browning compounds. 

Antinutritional factors (ANF) are frequently present in foods used primarily as protein sources. Chief among these are enzyme inhibitors, lectins, polyphenols and certain non-protein amino acids. All are capable of lowering the absorption and/or the utilisation of amino acids by the animal but are not taken into account in evaluations of protein sources based on amino acid content. The nature and mode of action of anti-nutritional factors is dealt with in Chapter 24 with particular reference to their importance in individual foods. 

Llener, I.E. (1975). Effect of anti-nutritional and toxic factors on the quality and utilization of legume proteins. In "Protein Nutritional Quality of Foods and Feeds", M. Friedman Ed., Marcel Dekker, New York, Part 2, pp. 523-550. 

Sathe, S.K., and Salunkhe, D.K., 1982, Investigations on winged bean [Psophocarpus tetragonolohus L. DC] proteins and anti-nutritional factors, J. Food Sci., 46 1389. 

Tannins were primarily considered as anti-nutritional biochemicals due to then-adverse effects on feed intake and nutrient utilization (Kumar and Vaithiyanathan 1990). Nevertheless in recent years, they have been recognized as nsefnl phytochemicals for beneficially modulating the rumen microbial fermentation. The effects of tannins on ruminant production have been published in the past, which primarily focused on the adverse effects of tannins on animal systan, with some discussion on their positive effects on protein metabolism and prevention of bloat (Mangan 1988 Kumar and Vaithiyanathan 1990 Aerts et al. 1999 Barry and McNabb 1999 McSweeney et al. 2001a Min et al. 2003 Mueller-Harvey 2006 Waghom 2008). This chapter focuses on the effects of tannins on ruminal microbial populations that affect N metabolism, methanogenesis and ruminal biohydrogenation process in the mmen. 

Heating can impair the nutritive value of a foodstuff not only by lowering nutrient availability but also by decreasing protein digestibility and producing anti-nutritional substances. In this case. 

Tubers Tubers are quite commonly consumed by villagers in Burma. Other tropical countries also report sporadic use of winged bean tubers (59). However, in comparison to the available data on the nutrient, anti-nutrient composition and the protein quality of the seed flour, published data on the nutritional value of winged bean tuber is somewhat limited. The few reported studies dealing with a larger number of varieties grown in different locations (25,67-71) show that tubers are mainly composed of protein and carbohydrates. 

Metabolic Transit. Free Amadori Compounds. It is well known that the synthetic Amadori compounds of the free amino acids are absorbed by the intestine and excreted unchanged in the urine (9,28,30). The transport is not active as observed with deoxyfructosyltryptophan (30) and c-deoxyfructosyllysine (40), and the level of absorption depends on the nature of the amino acid and on the conditions of ingestion. Nutritional assays and metabolic transit studies performed with radioactive Amadori compounds of tryptophan (12,30), leucine (12), and lysine (9,28,41) given orally or intravenously on normal or anti-biotics-treated animals have shown that the intestinal microflora can regenerate part of the amino acid. This can be absorbed subsequently at a very low level by the caecum or the large intestine and incorporated into the tissue proteins or utilized by the intestinal microflora. Barbiroli (13) showed also that some intestinal enzymes were able to liberate some amino acids from their Amadori compounds but to a very small... 

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