Submitted to: Institute of Food Technologists
Publication Type: Book / chapter
Publication Acceptance Date: 2/25/2010
Publication Date: 8/24/2010
Citation: Rashida, A., Shih, F.F., Riaz, M. 2010. Processing and functionality of rice bran protein and peptides. Institute of Food Technologists. 233-246. Interpretive Summary: Rice bran contains proteins, oil, and many other valuable ingredients that could be useful in food developments. Particularly, rice proteins are nutritious and hypoallergenic (allergy-free) for human consumption. Food-use properties of the protein vary, depending on processing conditions. For instance, solubility and emulsifying capacities normally increased with protein hydrolysis (breakdown) during treatment with acid, base, or enzymes. Peptides are the broken-down products from protein hydrolysis, which could be chemically active as health-enhancing ingredients.
Technical Abstract: Rice bran comprises approximately 10% of the rough rice kernel. Its germ is a rich source of oil; while defatted bran consists of proteins, minerals, vitamins and fibers, or the indigestible carbohydrates. About 61% of the minerals are located in the bran. The rice bran proteins have shown great potential for use in various foods. Alkaline extraction and isoelectric precipitation followed by papain hydrolysis produced peptides with superior functional properties. Protein hydrolysates have long been used as flavor promoters, especially with glutamic acid and its salts as monosodium glutamate (MSG); however, MSG has been banned in several countries because of the health concerns. Glutamines and asparagines are present in large amounts in RBPs, which if deaminated, may serve as excellent flavor enhancers in a variety of food systems; however, the peptides are also known to induce bitterness, and careful production of proteolysates plays the significant role in flavor development.