Proteins antinutritional factors

Sundower Seed. Compared to the FAO/WHO/UNU recommendations for essential amino acids, sunflower proteins are low in lysine, leucine, and threonine for 2 to 5-year-olds but meet all the requirements for adults (see Table 3). There are no principal antinutritional factors known to exist in raw sunflower seed (35). However, moist heat treatment increases the growth rate of rats, thereby suggesting the presence of heat-sensitive material responsible for growth inhibitions in raw meal (72). Oxidation of chlorogenic acid may involve reaction with the S-amino group of lysine, thus further reducing the amount of available lysine. 

Formulas tend to contain isolates as the protein source to eliminate or reduce the presence of carbohydrates that ate the cause of flatulence and abnormal stools. Care is taken to provide adequate nutrition and to use proteins processed in such a way as to minimize or eliminate any antinutritional factors. The formulation of a typical soy-based infant formula is also given in Table 17. 

CARBONARO M, GRANT G, CAPPELLONi M, puszTAi A (2000) Perspectives into factors limiting in vivo digestion of legume proteins antinutritional compormds or storage proteins JAgric Food Chem. 48 742-9. 

Tannins are one of several antinutritional factors present in dry beans. Any polyphenolic compound that precipitates proteins from an aqueous solution can be regarded as a tannin (11). Tannins precipitate proteins due to functional groups that complex strongly with two or more protein molecules, building up a large cross-linked protein-tannin complex (12). 

Various excellent reviews are available on phenolic compounds, their chemistry and analysis, content in foods and nutritional significance (Bravo, 1998 Dykes and Rooney, 2006 Manach et al., 2004 Naczk and Shahidi, 2006 Robbins, 2003). From a nutritional perspective, phenolic compoimds (especially tannins) are regarded as antinutritional factors due to their ability to form complexes with dietary proteins and minerals and digestive enzymes (Bravo, 1998). However, lately there has been increasing focus on the positive aspects of phenolics due to their ability to act as antioxidants which may offer potential health benefits such as prevention of diseases such as cancer and cardiovascular disease. 

The advantages of an animal bioassay are that protein digestibility, amino acid bioavailability, and the presence of antinutritional factors can be ascertained. However, animal-based feeding studies can be difficult. First, these assays are expensive to conduct and time-consuming. Secondly, these assays require animals... 

Such chemical changes may lead to compounds that are not hydrolyzable by intestinal enzymes or to modifications of the peptide side chains that render certain amino acids unavailable. Mild heat treatments in the presence of water can significantly improve the protein s nutritional value in some cases. Sulfur-containing amino acids may become more available and certain antinutritional factors such as the trypsin inhibitors of soybeans may be deactivated. Excessive heat in the absence of water can be detrimental to protein quality for example, in fish proteins, tryptophan, arginine, methionine, and lysine may be damaged. A number of chemical reactions may take place during heat treatment including decomposition, dehydration of serine and threonine, loss of sulfur from cysteine, oxidation of cysteine and methio-... 

Moisture is present in all materials rendered or cooked and plays an important role in the cooking reactions. Without sufficient moisture, the desired cook would not be achieved. Water or steam or both are often added to elevate moisture and to ensure proper denaturing and hardening of protein, rupturing of oil cells, and inactivation of undesirable enzymes, micro-organisms, and antinutritional factors. Water also assists in the displacement of fat from the surfaces of solid materials. Solids have a greater physicochemical affinity for water than for fat. 

The nutritional value of a food is determined by its protein quality, which depends mainly on its amino acid content, digestibility, influence of antinutritional factors, and the tryptophan to a large neutral amino acids ratio (Comai et al., 2007). 

Because of very high biological value and absence of antinutritional factors, except for some allergenic activity, milk proteins have found various application in formulated foods and as meat extenders. Initially only the caseins were used, but recently the recovery of whey proteins and their fractions was made economically feasible. 

Preparation of dry beans involves preliminary hydration followed by various heat treatments to obtain a tender, palatable product. Water and heat play an important role in chemical reactions, heat transfer and chemical transformations, such as protein denaturation and starch gelatinization. Inadequate water uptake may result in insufficient heat transfer to inactivate antinutritional factors and result in reduced cookability. In general, beans with an initial moisture content between 12 and 18%, are soaked to hydrate the seed to a moisture content of 53 to 57% and subsequently blanched, cooked or canned. This cooking step, if done for an optimal time, renders the seed nontoxic, improves digestibility, develops acceptable flavor and softens the seed coat and cotyledon. 

Alonso, R. E. Orue F. Marzo. Effects of extrusion and conventional processing methods on protein and antinutritional factor contents in pea seeds. Food Chem. 1998, 63, 505—512. 

In vitro protein digestibility of seaweed proteins is influenced by the species, seasonal period, and content of antinutritional factors such as phenolic and polysaccharides (Fleurence, 1999a Mabeau and Heurence, 1993). Activity of proteolytic enzymes may be reduced due to the reaction of amino acids with oxidized phenolic compound (Wong and Cheimg, 2001). Differences between the prediction of protein quality (based on amino acid content/amino acid requirement ratios) and the actual protein quality (based on the performance in living organisms) seem to be a reason of variations in the utilization of the amino acids comprised in different proteins. 

Tannins are defined as water soluble polyphenols which differ from noost other natural pol3rphenolic compounds in their ability to precipitate proteins, such as gelatin [3]. Tannins are the most abundant plant constituents, following celltilose, hemiceUulose, and lignin [4]. In tribal pulse Bauhinia malabarica Roxb.), tannins have been found to be one of the antinutritional factors, in addition to phenols, L-DOPA, and... 

---