Nutritional and Health Benefits of Soy Proteins

Abstract

Soy protein is a major component of the diet of food-producing animals and is increasingly important in the human diet. However, soy protein is not an ideal protein because it is deficient in the essential amino acid methionine. Methionine supplementation benefits soy infant formulas, but apparently not food intended for adults with an adequate nitrogen intake. Soy protein content of another essential amino acid, lysine, although higher than that of wheat proteins, is still lower than that of the milk protein casein. Adverse nutritional and other effects following consumption of raw soybean meal have been attributed to the presence of endogenous inhibitors of digestive enzymes and lectins and to poor digestibility. To improve the nutritional quality of soy foods, inhibitors and lectins are generally inactivated by heat treatment or eliminated by fractionation during food processing. Although lectins are heat-labile, the inhibitors are more heat-stable than the lectins. Most commercially heated meals retain up to 20% of the Bowman-Birk (BBI) inhibitor of chymotrypsin and trypsin and the Kunitz inhibitor of trypsin (KTI). To enhance the value of soybeans in human nutrition and health, a better understanding is needed of the factors that impact the nutrition and health-promoting aspects of soy proteins. This paper discusses the composition in relation to properties of soy proteins. Also described are possible beneficial and adverse effects of soy-containing diets. The former include soy-induced lowering of cholesterol, anticarcinogenic effects of BBI, and protective effects against obesity, diabetes, irritants of the digestive tract, bone, and kidney diseases, whereas the latter include poor digestibility and allergy to soy proteins. Approaches to reduce the concentration of soybean inhibitors by rearrangement of protein disulfide bonds, immunoassays of inhibitors in processed soy foods and soybean germplasm, the roles of phytoestrogenic isoflavones and lectins, and research needs in all of these areas are also discussed. This integrated overview of the widely scattered literature emphasizes general concepts based on our own studies as well as recent studies by others. It is intended to stimulate interest in further research to optimize beneficial effects of soy proteins. The payoff will be healthier humans and improved animal feeds.

Proteins of Bacuri almonds: nutritional value and in vivo digestibility

“…The content of all essential amino acids was higher than those recommended by FAO/WHO. Sulphurated Amino Acids (SAA) are limiting factors in many food plants such as soy (Friedman & Brandon, 2001), beans, other vegetables (Sgarbieri, 1987), and nuts (Fernandes et al, 2010;Czedera et al, 2012). The level of sulphurated amino acids (methionine + cysteine) of the raw bacuri almond protein was 33.9 %; this value is higher than that established by the FAO/WHO and those found for beans (19.95 %), wheat (18.12 %), corn (22.21 %), soy (18.65 %), and it was close to that found for beef (35.59 %) (Pires et al, 2006).…”

Procesamiento en seco de harina de chía (Salvia hispanicaL.): caracterización química de fibra y proteína Dry processing of chía (Salvia hispanicaL.) flour: chemical characterization of fiber and protein

“…Distribucio´n de las fracciones de proteı´na de la fraccio´n rica en proteı´na de S. hispanica. su concentracio´n, ya que pasaron de valores de 19 y 13 g/kg de proteı´na en la harina hasta 24 y 31 g/kg en la FRP respectivamente; esto es contrario a lo que se ha reportado (Friedman & Brandon, 2001), donde se asevera que el procesamiento y almacenamiento de la harina disminuye dra´sticamente el contenido de estos aminoa´cidos con la consecuente formacio´n de compuestos oxidados; pero en este caso, el procesamiento que no involucro´etapas hu´medas podrı´a estar contribuyendo al incremento de los mismos. Lo anterior manifiesta que la FRF posee un aporte bastante considerable con respecto de los aminoa´cidos azufrados.…”

Caracterização física, química e sensorial de sobremesas à base de soja, elaboradas com mucilagem de chia

“…Essa leguminosa é considerada um alimento funcional, devido ao seu alto teor de proteína, composição de gordura (rica em ácidos graxos insaturados), presença de isofl avonas e apropriado perfi l de minerais essenciais (FRIEDMAN & BRANDON, 2001).…”