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United States Department of Agriculture

Agricultural Research Service

Research Project: Rice As a Source and Delivery System for Nutrients and Lipophilic Bioactive Compounds

Location: Food Processing and Sensory Quality Research

2012 Annual Report

1a.Objectives (from AD-416):
Objective 1: Develop methods for enhancing bioactives in rice for applications in human diets to promote health. Objective 2: Utilize rice starch as a matrix for the effective delivery of lipophilic bioactive compounds [e.g., Vitamin A, gamma oryzanol and related ferulate esters), Co-Q10, omega 3-DHA, lycopene, polyphenols] through the development of porous rice starch granules and beads, spherical aggregates, and nanocapsules. Objective 3: Test the performance of the starch encapsulates in model food systems.

1b.Approach (from AD-416):
Several methods for the induction of phenolics, anthocyanins, phytoalexins, and lipophilic bioactive compounds in rice and rice bran will be developed. Products of the proposed research will be rice and rice bran enriched with bioactive compounds. A suite of rice flour/starch encapsulation systems that are capable of; a) delivering lipophilic bioactive compounds at desired levels, b) protecting these bioactive compounds against degradation during food processing and storage, c) masking flavor of bioactive compounds while not adversely affecting the sensory properties or stability of the final product, and d) delivering the bioactive compounds with desired bioavailability/bioactivity will be developed. How well the developed rice starch encapsulates perform in model fried, baked, and beverage products will be determined.

3.Progress Report:
Work was begun to induce bioactive compounds in rice. Initial experiments have focused on the effects of ultra violet (UV) irradiation, soaking time (water and elicitors), and fermentation with Aspergillu (A.) sojae on the total phenolic content of rice. Development of antioxidant assays and a glucose uptake assay in mouse adipocytes has been completed. Preliminary screening of 8 different rice varieties using bran extracts indicated one purple and one red rice variety stimulated in vitro glucose uptake. Also, bran from brown rice varieties are being tested to provide a basis for future rice elicitor studies.

Work was completed to produce a rice starch encapsulate of Coenzyme Q10, a health-enhancing antioxidant. This enzyme was encapsulated in rice starch that was chemically modified to facilitate association with the enzyme. Modification of the rice was needed to improve compatibility of the starch with materials that are less hydrophilic, (i.e., components that are not very soluble in water). The particles were formed by modifying the starch, then forming an emulsion with the additives and freeze drying the mixture to produce dry particles. The resulting capsules have shown improved solubility in water, stability during storage, and bioavailability of the enzyme in the human digestion system.

As a second approach to use rice-based encapsulating materials, blueberry phenolics were encapsulated in porous rice particles prepared by alcoholic dehydration of gelatinized rice flour and starch slurries. The treatment allowed some of the phenolics to be taken up in the pores of the starch. These products show superior solubility and stability properties, and can be used in different foods, e.g., baked goods and beverages.

Work was also continued with cooperative research and development agreement partner to support their efforts to extend the development of rice-based batters for foods.

1. Production of rice-based encapsulates. Scientists at the Southern Regional Research Center in New Orleans, LA, have produced nano-scale encapsulation of Co-Enzyme Q-10 with rice starch and micro-scale encapsulation of blueberry phenolics with porous rice flour and starch. Encapsulation of bioactive components improves several characteristics important to food products; including the extension of shelf life, removal of bitter taste, and increased bioavailability. The characteristics of these two encapsulates will provide a unique delivery system of healthy bioactive compounds into baked foods and beverages, with improved taste characteristics and improved oral bioavailability. This research will provide healthier food products and will benefit consumers and also farmers by utilizing waste products (blueberry, pomace, etc).

2. Rice bran extracts stimulate in vitro glucose uptake in mouse adipocytes. Improved glucose homeostasis is important for the treatment of Type II diabetes and pre-diabetes. Southern Regional Research Center scientists in New Orleans, LA, have screened different varieties of rice and rice bran extracts for increased in vitro glucose uptake. Data obtained from brown rice and rice bran extracts will provide baseline information to be used in further testing of elicitor-treated rice extracts. Two rice varieties, one red and one purple (black), have displayed higher glucose uptake. These preliminary results point to specific rice varieties with the potential for improving glucose imbalances in patients with Type II diabetes and pre-diabetes.

Review Publications
Wood, C.E., Boue, S.M., Collins-Burow, B.M., Rhodes, L.V., Register, T.C., Cline, J., Dewi, F.N., Burow, M.E. 2012. Glyceollin-elicited soy protein consumption induces distinct transcriptional effects as compared to standard soy protein. Journal of Agricultural and Food Chemistry. 60(1):81-6.

Bett Garber, K.L., Champagne, E.T., Thomson, J.L., Lea, J.M. 2011. Relating raw rice color and composition to cooked rice color. Journal of the Science of Food and Agriculture. 92:283-291.

Last Modified: 4/20/2014
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