Location: Food Processing and Sensory Quality Research
2021 Annual Report
Objectives
Objective 1: Develop commercially viable processing technologies that produce health-promoting foods from whole grain rice and rice co-products. [NP306, C1, PS1A, 1B] (S. Boue, J. Beaulieu)
Sub-Objective 1.1. In this sub-objective research will characterize different rice processing techniques with emphasis on increasing health-promoting rice components (phytonutrients). Processing will include different cooking methods of table rice, parboiling, drum drying and extrusion of rice co-products.
Sub-Objective 1.2. Establish temporal boundaries during sprouting between de novo synthesis of health-beneficial phytonutrient compounds versus catabolic loss or change in macronutrients.
Objective 2: Enable commercial uses of whole grain rice and other crops as sprouts and microgreens in value-added foods and functional products. [NP306, C1, PS1B, 1C] (J. Beaulieu, S. Boue, Vacant - Sensory Scientist)
Sub-Objective 2.1. Develop value-added products (e.g. beverages, powders, flours) from select, optimized, sprouted colored bran rice and grain varieties, and commercially important sprouted crops.
Sub-Objective 2.2. Rice flour enriched with phytonutrients by sprouting and resistant starch by processing (from Sub-Objective 1.1) will be utilized as an ingredient in several rice functional foods.
Approach
Brown and colored rice will be analyzed using different cooking methods to determine methods to produce resistant starch and determine health benefits. Several processing methods will require rice to be milled to a flour. Rice processing methods and assays (in vitro and in vivo) to produce resistant starch and determine health benefits: Measurement of starch types will be conducted and compared to other starch sources. An in vitro fermentation system will be utilized to determine the effects of rice and rice ingredients on gut health. Research at the SRRC will germinate several rice varieties, including sprouted germinated brown rice, high protein rice and colored rice. Green technologies will deliver a free-flowing germinated brown rice beverage, with limited GRAS additions. A process developed at the SRRC has created the foundation for preliminary germinated brown rice beverages. Rice flour that is enhanced with resistant starch and polyphenolics from sprouted rice will be extruded into foods and analyzed for bioactive and phytonutrient content. Rice flour without added resistant starch and not sprouted will be the control. A sensory panel will determine if flavor and texture are comparable to foods produced from commercially available rice flour.
Progress Report
Objective 1, brown rice and sprouted brown rice beverages created by ARS scientists in New Orleans, Louisiana using novel green technologies and small-scale protocols resulted in rice beverages with ~5% protein, which was ~10% soluble. Larger scale production of rice sprouts and beverages is ongoing. Further research by ARS scientists in New Orleans, Louisiana is examining the resistant starch content of new rice varieties being developed with higher quantities of resistant starch. Additionally, research showed rice resistant starch creates healthier food batters. Resistant starch in rice is typically at low levels and requires enzymatic processing and heating/cooling steps to decrease starch digestibility. Different processing methods were evaluated to increase resistant starch from native rice starch. It was found that adding resistant starch to rice batters or using a high resistant starch rice flour significantly increased resistant starch contents after frying. Additionally, increasing the resistant starch content did not significantly alter the oil absorption content of fried rice batters, which were all significantly lower in oil content when compared to fried wheat batter. This research will assist stakeholders that are developing health-promoting food ingredients and consumers seeking healthy foods.
Objective 2, acidified beverages are currently being formulated by ARS scientists in New Orleans, Louisiana with rice and sorghum brans before undergoing phenolic and volatile analyses and sensory testing. Results are expected to expand applications of antioxidant-rich cereal brans into value-added beverages and increase understanding of consumers’ perceptions of these products.
Through contacts made at the Institute of Food Technologists meeting, an ARS scientist in New Orleans, Louisiana formulated novel ideas and a key collaboration which aided in the writing of the new project plan. This resulted in specific elements added to the approach and milestones. This collaboration was solidified through a formal Letter of Support, and then an 1890’s Faculty Research Sabbatical Program proposal, through a Historically Black College and University (HBCU) that will begin this summer.
An extramural agreement has been established with Tulane University School of Medicine to determine the health benefits of activated foods from rice, and other Louisiana grown crops. ARS scientists in New Orleans, Louisiana will develop methods to increase health-promoting components in rice foods, and Tulane scientists will utilize in vitro and in vivo techniques to evaluate biological activities.
Accomplishments
1. Resistant starch reduces obesity and modulates the gut microbiome. ARS scientists in New Orleans, Louisiana, suggest an estimated 160 million Americans are either obese or overweight and this leads to an increased risk of type 2 diabetes, heart disease, and cancer. Interestingly enough, research has identified gut bacteria that are altered with obesity. After eating rice, normal rice starch is rapidly digested and absorbed as glucose that can then result in hypoglycemia. Newer rice varieties have been developed that contain higher amounts of resistant starch that are not rapidly digested. In collaborative research between the ARS scientists in Stuttgart, Arkansas, New Orleans, Louisiana, and Beltsville, Maryland, the researchers conducted an 8-week rodent feeding study with low and high fat diets utilizing cooked rice with varying amounts of resistant starch: low (0.1% resistant starch), medium (1% resistant starch) and high (8.6% resistant starch). The results showed the body fat mass gain with a high fat diet was reduced in the medium and high resistant starch groups. Gut analysis determined that mice fed with enhanced resistant starch levels had a decreased Firmicutes to Bacteroidetes ratio (lower obesity risk) and decreased opportunistic pathogens and bacterial families associated with obesity. Overall, resistant starch consumed in the form of rice can exert concentration-dependent effects on the gut microbiome in mice which may have a protective effect against obesity.
