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):
A continuous extraction system scalable for industrial production of soluble rice bran protein concentrates (>70% protein) and isolates (>90% protein) will be designed employing subcritical water. The subcritical water process will be designed to also allow separation of the lipids with their associated lipophilic bioactive compounds, high demand lecithin, hydrolyzed starch, and fiber fractions for incorporation in food and beverage products. 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:
Several methods have been developed to induce bioactive compounds in rice. Initial experiments have focused on the effects ultraviolet irradiation (UV-C and UV-B), soaking time (water and elicitors), and fermentation with aspergillus sojae on the total phenolic content of rice. Both brown rice and colored rice have been used for the induction of bioactives. Analysis of 12 different rice varieties using bran extracts indicated 4 purple, and 4 red rice varieties stimulated in vitro glucose uptake. Additionally, the influence of cooking rice on flavor and antioxidant activity were evaluated. Nine commercial rice samples (3 brown, 3 red, and 3 purple) were cooked with salt, oil, or both. The addition of salt, and salt with oil, significantly reduced bitter, waterlike/metallic, and astringent flavors. Antioxidant activities of cooked rice extracts were evaluated by hydrophilic oxygen radical absorption capacity (H-ORAC) method with purple>red>brown rice. Agricultural Research Service (ARS) will have the continued support of a Cooperative Research and Development Agreement (CRADA) for the use of low oil absorbing rice batters. Assistance was given to the CRADA partner in submission of SBIR grant to further develop the use of rice batters for other foods. This past year the development of a rice bran-blueberry prebiotic was initiated. Rice bran and blueberry pomace (leftover pulp from juice manufacturing) are typically low value waste products. Both blueberry juice and pomace extracts are being used to complex rice bran. By complexing rice bran (protein component) with blueberry phenolics (anthocyanins) a value-added food product for prediabetics is formed without added sugar. An industry partner is interested in the technology and a Cooperative Research and Development Agreement (CRADA) is being developed. The rice bran-blueberry complex would be used in foods to treat prediabetic patients. 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.
1. Production of a rice bran-blueberry prebiotic for the treatment of prediabetes. Rice bran and blueberry pomace (leftover pulp after juice production), two low value waste products, have been combined to form a value-added prebiotic with the potential to promote healthy blood sugar levels. Both blueberry juice and pomace extracts are being utilized. ARS scientists at the Southern Regional Research Center, New Orleans, LA, in cooperation with a scientist from Nutritional Medicines for Health in New Orleans, LA, are complexing rice bran (protein component) with blueberry phenolics (anthocyanins) to produce a value-added food product for prediabetics without added sugar. Data collected indicate beneficial anthocyanins and phenolics are retained by rice bran. A CRADA agreement is pending approval. This rice bran-blueberry prebiotic creates a value-added food product for the treatment of prediabetic patients.
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 prediabetes. ARS scientists at Southern Regional Research Center, New Orleans, LA, are screening different varieties of rice (with and without cooking) 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. Eight rice varieties, four red and four purple (black), have displayed stimulation of glucose uptake in apidocytes. These preliminary results point to specific rice varieties with potential for improving glucose imbalances in patients with Type II diabetes and prediabetes.
Patindol, J.A., Shih, F.F., Ingber, B.F., Champagne, E.T., Boue, S.M. 2013. Porous rice powder from the precipitation of gelatinized flour or starch paste with ethanol. Starch/Starke. 65:296-303.