SOYBEAN AND HEALTH - University of Macau Library

14Beneficial Effects of Bioactive Peptides Derivedfrom Soybean on Human Health and TheirProduction by Genetic EngineeringChin Feng Liu and Tzu Ming PanDepartment of Biochemical Science and Technology, College of Life Science,National Taiwan UniversityTaiwan1. IntroductionSoybean [Glycine max (L.) Merrill] is one of the oldest cultivated crops of the Far East. Forcenturies, the Oriental people, including the Chinese, Japanese, Koreans, and SoutheastAsians, have used soybean as a staple source of dietary protein and oil. It is one of the fivecommercial food crops, besides rice, wheat, barley, and millet. Soybean is very important forvegetarians and vegans because of its high protein content and abundance of vitamins,minerals, and fiber. Because of its versatility, it can be prepared into a variety of foods,including fermented and nonfermented foods.Asians consume about 20–80 g of traditional soy foods daily, the most common being tofu,miso, and tempeh (Fournier et al., 1998; Messina & Flickinger, 2002), whereas Americansconsume only about 1–3 g daily (Cohen et al., 2000; Fournier et al., 1998), mostly inprocessed forms such as soy drinks, breakfast cereals, and energy bars. Soybean-based foodshave generated much interest because of the evidence that consumption of large amounts ofsoybean can lower the risk of chronic diseases such as cardiovascular disease and cancer;this effect is particularly noticeable among Asian populations because of their high soy foodintake (Kulling et al., 2001; Persky et al., 2002; Tikkanen & Adlercreutz, 2000). In addition,consumption of soy foods may reduce the risk of osteoporosis and help alleviatemenopausal symptoms (Genovese & Lajolo, 2002; Messina, 2000; Persky et al., 2002), whichare major health concerns for women.Soybean-based foods contain an array of biologically active compounds that can conferimportant health benefits such as antioxidant effects (Setchell, 1998; Tsai & Huang, 1999).These phytochemicals include saponins, phytates, protease inhibitors, phenolic acids, andlecithin, all known for their anticancer potential (Cohen et al., 2000; Messina & Flickinger,2002); phytosterols, which have hypocholesterolemic effects; isoflavones, which are knownfor several health benefits (Fukui et al., 2002); and omega-3 fatty acids, which have wellrecognizedcardioprotective effects. Among these compounds, isoflavones have attractedthe most attention (Messina & Flickinger, 2002; Messina & Loprinzi, 2001).The proteins β-conglycinin (7S globulin) and glycinin (11S globulin) constitute up to 90% of thetotal soy protein (Gianazza et al., 2003). Evaluation of these dietary proteins is very interestingbecause their hydrolysis by proteases produces peptides with biological activities. A growing