Location: Food Processing and Sensory Quality Research
2020 Annual Report
Objectives
Objective 1: Enhance the human bioactive properties of resistant starch and slowly digestible starch in commercial table rice (milled, brown, and colored) while maintaining sensory texture characteristics.
Sub-Objective 1.1. In this sub-objective research will characterize the sensory characteristics related to resistant starch, slowly digestible starch, and the optimization of healthy starch in cooked rice.
Sub-Objective 1.2. Under this sub-objective several methods to produce high-resistant rice starch in flour will be examined in a baked food product. Resistant starch has many colonic health-promoting properties, but often does not formulate well as an ingredient in baked foods.
Objective 2: Enable new commercial functional food products using whole grain rice and rice co-products.
Sub-Objective 2.1. In joint research with CrispTek research in this sub-objective will focus on adding resistant starch, fiber, and protein to current low-oil absorbing frying batters utilizing rice foods and co-products. Nutritionally-enriched baked and fried foods will be developed that sustain sensory quality.
Sub-Objective 2.2. Healthier rice milk beverages and improvement of rice bran soluble protein extraction for food and beverage use will be developed.
Sub-Objective 2.3. The proposed research will develop and compare several methods to produce unique rice prebiotics combined with phenolics from blueberry pomace and spent green tea. The effectiveness of each prebiotic will be evaluated utilizing in vitro fermentations and a mouse model for colonic health.
Approach
Rice varieties vary in amylose content that lead to differences in digestibility. Cooked table rice from different varieties will be evaluated for the amount of resistant, slowly digestible, and rapidly digestible starch based on in vitro digestion times. Thermal processes and physicochemical methods will be used to produce high resistant starch content in rice flour and starch, which will be tested as ingredients in baked foods. In collaboration with CrispTek, research will focus on adding resistant starch, fiber, and protein from rice foods and co-products to current low-oil absorbing frying batters. Nutritionally-enriched baked and fried foods will be developed with sustained or enhanced sensory qualities. Rice beverages will be developed that incorporate green technologies (e.g. focusing on raw materials and enzymatic treatments that do not rely upon previous stabilization). Lastly, methods will be evaluated to produce prebiotics from rice that include thermal and physiochemical methods and encapsulation technologies.
Progress Report
This is the final report for project 6054-41000-107-00D. Progress was made by ARS researchers at New Orleans, Louisiana, on the 2 objectives, both of which fall under National Program 306, Quality and Utilization of Agricultural Products recognizes this research need as part of Problem Statement 1.C: New Bioactive Ingredients and Functional Foods. The Problem Statement relays that the development of functional foods requires delivery systems to carry, protect, and deliver health-promoting food ingredients to their specific site of action at the right time and at a specific rate. This is the final report and the following summarizes the progress/accomplishments over the 5 year lifespan of the project:
In support of Objective 1, research showed that varying rice starch types affects sensory evaluation. Sensory analysis was conducted by ARS researchers at New Orleans, Louisiana, on rice with different starch types and the data analysis of the diverse resistant/slowly digestible starch rice confirmed that 70% of the sensory variation is due to amylose content. This indicates that sensory differences in rice are partly due to the resistant, slowly digestible, and rapidly digestible starch fractions. Further research detailed 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 increase resistant starch content. Different processing methods were evaluated to increase resistant starch from normal rice starch.
In support of Objective 2, ARS scientists at New Orleans, Louisiana, combined rice bran with blueberry phenolics to produce unique prebiotics. Rice bran and blueberry pomace (leftover pulp after juice production) have been combined to form a value-added prebiotic with the potential to promote healthy blood sugar levels. ARS scientists at New Orleans, Louisiana, in cooperation with a partner have complexed rice bran and other rice ingredients with blueberry phenolics (anthocyanins) to produce value-added food products for prediabetics. Another study showed that colored rice uses two mechanisms to treat diabetes. Improved glucose homeostasis is important for the treatment of Type II diabetes and prediabetes. ARS researchers at New Orleans, Louisiana, found colored rice increased glucose uptake in fat cells. This research determined that both red and purple rice delay starch digestion through inhibition of the digestive enzymes a-amylase and a-glucosidase. The inhibition of digestive enzymes delays digestion and absorption of carbohydrates leading to suppression of postprandial hyperglycemia. ARS scientists at New Orleans, Louisiana, worked with international collaborators to examine 6 red rice varieties of Oryza sativa that have been cultivated at the Africa Rice Center in the Republic of Benin. Further research detailed 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 increase resistant starch amounts. Completed studies on fried rice batters containing added resistant starch maintained the benefits of lowered oil uptake and had desirable texture (hardness/crispness). Additionally, fried onion strips with rice batters containing high resistant starch still retained good sensory quality. This research will assist stakeholders that are developing health-promoting food ingredients and consumers seeking healthy fried and baked foods.
Under Subobjective 2.2, a commercial blender and pilot plant multi-processing vessel were used by ARS researchers at New Orleans, Louisiana, to optimize brown rice heating and emulsifying parameters. This required step will facilitate pilot plant-scale brown rice beverage formulations through pasteurization. Particle size was used to monitor the emulsification process, which operated at temperatures below rice gelatinization. Evaluation of preliminary beverages resulted in protein and oil characterization, in the form of four manuscript submissions. Germinated brown rice beverages were compared to non-germinated white and brown rice beverages produced in-house, as well as commercially available rice beverages.
Germinated brown rice beverages contained higher protein levels than non-germinated beverages. In-house developed beverages had markedly higher protein concentrations (~5%) than commercial rice beverages (previously reported at 0 – 0.12% protein), and this protein level is five times higher than common US rice beverage nutrition labels. A potentially novel low molecular weight peptide band was found using gel electrophoresis, which is believed to be partially responsible for protein solubility. Protein solubility test indicated that roughly 9.3 – 11.0% of the material was soluble in developed beverages. Brown and germinated brown rice beverages contained the significantly highest level of triacylglycerols and diacylglycerols and total free sterol, compared against several well-characterize rice beverage reported in the literature. Only the germinated and enzyme-treated materials conveyed a significantly higher relative percentage of the gamma-oryzanol into the beverages. These are valuable finding regarding possible health-related advantages utilizing this green, free-flowing processing methodology that delivers a fully 100% natural, no additives (oils, sugars, emulsifiers, fortification), plant-based beverage.
The initial processing protocol demonstrated that post-wet-milling and post-enzyme beverage sieving losses contained the highest significant levels of protein, triacylglycerols, diacylglycerols, free sterols, phytosterol esters and gamma-oryzanol recovered in each beverage type. These sieving losses should be effectively nullified through revised emulsification processing, which keeps all native constituents intact using developed methods and in situ processing. According the Information Resources Inc., US plant-based beverage sales increased 6.2% in a year through 2019, and attained $1.7 billion sales. Developing plant-based, protein-rich functional beverages with an agronomically cheap rice input ingredient with proven heath-beneficial attributes will have positive economic impact.
Through contacts made presenting posters at the Institute of Food Technologists in 2019, an ARS scientist at New Orleans, Louisiana, formulated novel ideas and a key collaboration for the project plan re-write, which 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.
Accomplishments
1. Development of a novel green germinated brown rice beverage process. Consumers are concerned about saturated fat levels in foods, lactose intolerance, hormone and antibiotic levels in dairy products, as well as sustainable treatment of the environment. The functional beverage market offers a consumer-friendly mechanism to rapidly ingest healthy alternates, compared to other beverages. ARS researchers in New Orleans, Louisiana, developed methods to deliver superior all natural value-added rice beverages using green technologies. “Green technologies” for food processing was defined as sustainable, less harmful to the environment, and safe natural chemical processes used to transform raw products into value-added foods and ingredients, including use of endogenous and food grade enzymes which, provide reaction specificity, sensitivity and non-toxicity. An Invention Disclosure was submitted (Docket # 0162.18. Suspended), resulting in transfer of knowledge through publication. A novel method was described for germinating and processing unstabilized raw brown rice (never frozen, dried, solvent treated or preserved), leading to a completely green process and free-flowing soluble matrix rendering sprouted brown rice beverages. The “green” sprouted brown rice beverage developed has no additives, fortifications, added oils or salts. The method has very low inputs, is rather simple in terms of required equipment, and is applicable for both germinated brown and colored rice varieties. Only rice and soy offer agronomic crop acreages and yields, and reduced price-point inputs compared to most other plant-based beverage alternatives. Global dairy alternatives plant-based beverage market is expected to surpass $34 billion by 2024. Developing plant-based, protein-rich functional beverages with a cheap input ingredient with proven heath-beneficial attributes will have positive economic impact.
2. Development of nutritious rice beverages. Current rice beverages are low in protein content (generally under 1%). Brown rice and sprouted brown rice beverages created by ARS researchers in New Orleans, Louisiana, using novel green technologies and protocols resulted in preliminary beverages with about 5% protein, which was roughly 10% soluble. Brown and germinated brown rice samples and post-enzyme treated beverages generally contained the highest level of potential health-beneficial compounds, such as triacylglycerols, diacylglycerols, total free sterols and gamma-oryzanols, compared to in-house white rice beverages or commercial rice samples. These are valuable findings considering the possible health-related compounds identified. Further characterization using modified methods that capture all previously documented sieving losses, and pilot plant scale-up, should position this advantageous green processing methodology to deliver 100% natural, no additives, value-added germinated rice beverages. This is important industrially and economically considering the burgeoning plant-based beverage market and industries desire to capture more non-animal protein and health-related attributes, from an agronomic relatively inexpensive rice crop.
3. Resistant starch reduces obesity. An estimated 160 million Americans are either obese or overweight. Obesity is associated with increased risks for type 2 diabetes mellitus and heart disease, and cancer. Further research has identified gut microbial populations that are altered with obesity. After eating rice, normal rice starch is rapidly digested and absorbed as glucose, potentiating a hyperglycemic response and triggering insulin secretion and tissue-specific intracellular uptake of 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 researchers 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. Microbiome 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.
Review Publications
Beaulieu, J.C., Reed, S.S., Obando-Ulloa, J.M., Mcclung, A.M. 2020. Green processing protocol for germinating and wet milling brown rice beverage formulations: Sprouting, milling and gelatinization effects. Food Science and Nutrition. 2020(8):2445-2457. https://doi.org/10.1002/fsn3.1534.
Adhikari, A., Parraga Estrada, K.J., Chhetri, V., Janes, M., Fontenot, K., Beaulieu, J.C. 2019. Evaluation of ultraviolet (UV-C) light treatment for microbial inactivation in agricultural waters with different levels of turbidity. Journal of Food Science and Nutrition. 8:1237-1243. https://doi.org/10.1002/fsn3.1412.
Wan, J., Wu, Y., Pham, Q., Yu, L., Chen, M., Boue, S.M., Yokoyama, W.H., Li, B., Wang, T.T. 2019. Effects of rice with different amounts of resistant starch on mice fed a high-fat diet: attenuation of adipose weight gain. Journal of Agricultural and Food Chemistry. https://doi.org/10.1021/acs.jafc.9b05505.
Beaulieu, J.C., Lloyd, S.W., Obando-Ulloa, J.M. 2020. Not-from-concentrate pilot plant ‘Wonderful’ cultivar pomegranate juice changes: Quality. Food Chemistry. 318(2020):126453. https://doi.org/10.1016/j.foodchem.2020.126453.
Beaulieu, J.C., Reed, S.S., Obando-Ulloa, J.M., Boue, S.M., Cole, M.R. 2020. Green processing, germinating and wet milling brown rice (Oryza sativa) for beverages: Physicochemical effects. Foods. 9:1016. https://doi.org/10.3390/foods9081016.
