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United States Department of Agriculture

Agricultural Research Service

Research Project: Optimization of the Nutritional, Functional, and Sensory Properties of Raw and Processed Legumes, Grains, and Specialty Crops

Location: Healthy Processed Foods Research

2012 Annual Report

1a. Objectives (from AD-416):
Objective 1: Characterize the physical, chemical, functional properties and biological activity of raw materials and food products from legumes, almonds, grapes, olives, and wild rice. • Sub-objective 1.1. Pinpoint and identify impact aroma compounds of raw materials and food products from legumes, almonds, grapes, olives, and wild rice using GC-Olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Study flavor variation in different varieties. • Sub-objective 1.2. Isolate and characterize phytonutrients in raw materials and food products from legumes, almonds, grapes, olives, and wild rice. Determine the effects of processing on the levels of these constituents and also monitor changes in biological activity (i.e., antioxidant activity). Objective 2: Add value to legumes, barley, rice, and potatoes and their fractions using extrusion, concentration and size reduction technologies to modify, control or enhance their nutritional, functional and sensory properties for the development of convenient and desirable gluten containing and gluten-free products with higher quality, shelf life and health benefits. • Sub-objective 2.1. Develop healthy, nutritious, and convenient snack foods from legumes, barley, rice, wheat, apple, and potatoes, and their fractions using extrusion processing and forming technologies. • Sub-objective 2.2. Develop legume-based beverages formulated with conventional and non-conventional food ingredients, flours and protein powders from rice, wheat, and barley cooked by extrusion processing, drum drying, open kettle, pressure cooking, microwave cooking, and infrared cooking. The resulting cooked legume-based products in the form of powders will be used directly or pretreated by high pressure, microfluidizer processing, and high shear technology, as the base component for beverages with functional properties. This project involves the production of novel snack foods and beverages from legumes, barley, rice, potatoes and other agricultural products. The development of nutritious and tasty foods requires knowledge about the phytonutrients and flavor precursors present in the raw materials. The effects of processing on phytonutrient and flavor concentrations will be studied and processing parameters will be optimized to preserve these constituents. The scientists on this project have expertise in their respective areas and will work closely to achieve the objectives.

1b. Approach (from AD-416):
Extrusion processing will be used to produce new value-added foods with enhanced nutritional and sensory properties. Extrusion operational parameters such as moisture content, temperature, feed rate, screw speed and screw element configuration will be optimized. Ingredients from barley, rice, and potato will be added to legume flours to enhance the physicochemical properties of the extruded products including both snacks and beverages. To understand the influence of processing on flavor, phytonutrients and antioxidant activity, qualitative and quantitative studies will be performed on the agricultural products before and after processing. Impact flavor constituents will be localized, characterized and quantified using aroma extract dilution analysis (AEDA), gas chromatography-mass spectrometry (GC-MS), calculation of odor units, and preparation of aroma models. Aroma compounds responsible for desirable and undesirable flavor characteristics will be identified and formation pathways will be elucidated. Phytonutrients will be separated, characterized and quantified using HPLC-DAD, HPLC-MS and 1H and 13C NMR spectroscopy. Antioxidant activity will be measured by the DPPH and ABTS assays.

3. Progress Report:
We assessed the effect of extruded legumes fortified with chromium yeast for normalizing or preventing obesity and hypercholesterolemia in obese and normal mice models. Expanded extruded snacks were fabricated containing chromium yeast at concentration ranging from 1-30 micrograms/g. Obese mice ingesting the extruded food product containing chromium yeast had lower liver triglycerides and cholesterol content and lower abdominal adipose weight. In collaboration with our CRADA partner a patent application was filed. Culinary rhubarb is consumed as a vegetable and is prized for its use in pies, tarts and sauces. Rhubarb stalks are also processed for jam, jelly, compote, juice and wine and used as ingredients in ice cream, yogurt, candies and other specialties. The roots and rhizomes of rhubarb have been extensively studied due to their importance as medicines to treat constipation, inflammation and cancer. However, much less is known about the composition and activity of the stalks. Therefore, we studied the antioxidant activity, phenolic and anthocyanin content of twenty-nine rhubarb varieties. Seven of the varieties (Plum Hutt, Valentine, Minnesota No. 8, Cherry Red, Cawood Delight, Coulter McDonald and OR 23) had higher total phenolics than kale, a vegetable with high total phenolics. Anthocyanin concentration in rhubarb was moderate, ranging from 19.8 ± 1.5 to 341.1 ± 41.6 mg/100 g DW. Valentine, Plum Hutt and Minnesota No. 8 had the highest antioxidant activity of the varieties investigated. Because of their high total phenolics content and antioxidant activity, Plum Hutt, Valentine and Minnesota No. 8 appear to have potential nutritional advantages over other varieties although additional studies are needed to determine their phenolic composition. The use of rice protein concentrate a byproduct of rice syrup production, for the development of value-added gluten-free pasta formulated with legume pulses and other sources and forms of starch and dietary fiber was also investigated. Rice protein concentrate and legume pulse-based prototype gluten-free extruded pastas were fabricated. Preliminary selected formulations were hydrated into dough using different amount of water at room temperature. The test indicated that the ingredients were not evenly homogenized, presented a grainy feeling, and the resulted pasta were brittle. Luke warm water was shown to help making more homogenized dough. A combination of xanthan gum and guar gum was compared to konjac xanthan gum to see the differences in holding ability. Konjac xanthan gum showed a better holding ability on the pasta. Preliminary bench sensory result showed that extrusion improved the final texture of the pasta. The results demonstrated that novel, nutritious, high value gluten free pastas can be fabricated using rice protein concentrate as an ingredient in combination with pulses and selected forms of starch and dietary fiber. A patent application will be drafted and submitted based on the developed product and technology.

4. Accomplishments
1. Lentil-based extruded snacks. Lentil-based extruded snacks fortified with nutritional yeast were developed as a healthy alternative to traditional snacks. The product contained lentils, a food high in protein and B-glucan, and 1-20% (by weight) nutritional yeast. The product is highly acceptable as judged by a sensory panel. Studies evaluating the glycemic index (GI) in 10 human subjects showed that the extruded lentil snacks have great potential as a healthy, low-GI alternative to traditional snacks.

2. Styrene in black-ripe table olives. The concentration of styrene in 34 imported and domestic black-ripe table olive samples was determined. Domestic-grown table olives generally contained very low styrene concentrations (10 micrograms/g or less) while moderate to high concentrations (up to 1,830 micrograms/g) were found in some olives grown overseas. Styrene was recently added to a government warning list (12th Report on Carcinogens (RoC) compiled by the National Toxicology Program) of known and potential carcinogens. Styrene may result from mold contamination. These results may lead to U.S. quality/safety standards for styrene levels in olives.

Review Publications
Takeoka, G.R., Ebeler, S.E. 2011. Progress in authentication of food and wine. American Chemical Society Symposium Series. p. 1-11. DOI:10.1021/bk-2011-1081.ch001.

Takeoka, G.R., Buttery, R.G. 2012. Preparation and characterization of 2-formyl-1,4,5,6-tetrahydropyridine, a compound with a cracker-like odor. Journal of Food Chemistry. 132:2131-2134.

Nayak, B., Berrios, J.D., Power, J.R., Tang, J. 2011. Effect of extrusion on the antioxidant capacity and color attributes of expanded extrudates prepared from purple potato and yellow pea flour mixes. Journal of Food Science. 76(6):C874-C883. DOI: 10.1111/j.1750-3841.2011.02279x.

Nayak, B., Berrios, J.D., Power, J.R., Tang, J. 2011. Thermal degradation of anthocyanins from purple potato (Cv. Purple Majesty) and their impact on antioxidant capacity. Journal of Agriculture and Food Chemistry. 59(20):11040-11049. DOI: 10.1021/jf201923a.

Nayak, B., Berrios, J.D., Power, J.R., Ji, Y., Tang, J. 2011. Colored potatoes (Solanum tuberosum L.) dried into antioxidant-rich value-added foods. Journal of Food Processing and Preservation. 35(5):571-580.

Nayak, B., Liu, R., Berrios, J.D., Tang, J., Derito, C. 2011. Bioavailability of antioxidants in extruded products prepared from purple potato and dry pea flours. Journal of Agricultural and Food Chemistry. 59(15):8233-8243. DOI: 10.1021/jf200732p.

Last Modified: 06/23/2017
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