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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

2011 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 (Takeoka). • 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) (Takeoka, Berrios).

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 (Berrios, McHugh, Takeoka). • 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 (Berrios).

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
This report documents progress for the parent Project 5325-41000-053-00D that started in July 2010 and continues research from Project 5325-41000-052-00D.

Colored potatoes (Solanum tuberosum L.) are a significant source of antioxidants from polyphenols, carotenoids and ascorbic acid. In this study, the retention of total antioxidants in fresh colored potatoes and processed potato flakes prepared as potential ingredients for snack foods was studied. Total antioxidant capacity, total phenolics and total anthocyanins were higher in purple potato flesh compared with those from red, yellow and white potato cultivars. Peeled purple potatoes were blanched and dehydrated by freeze drying (FD), drum drying and refractive window drying to prepare potato flakes. No significant losses in total antioxidant capacity and total phenolic content in flakes were observed with all drying methods studied. However, 45, 41 and 23% losses in total anthocyanins were observed in potato flakes after FD, drum drying and refractive window drying, respectively. Colored potatoes could provide an excellent source of antioxidant-rich ingredients for the production of nutritionally enhanced food products.

Foods with antioxidant capacity provide protection against certain forms of cancers, cardiovascular and Alzheimer’s diseases caused by oxidative damages and contribute health benefits. The effect of extrusion cooking on the antioxidant capacity and color attributes of extruded products prepared from three selected formulations of purple potato and yellow pea flours using a co-rotating twin screw extruder were studied. The total antioxidant capacities (TAC) of the extruded products were not significantly different (p < 0.05) from their respective raw formulations. The total phenolic contents (TP) of the extruded products varied from 2088 to 3766 µg of gallic acid equivalents/g dry weight sample and retained 73 – 83 % of TP from the raw formulations after extrusion. Compared with their raw formulations, significant losses (60–70%) of the total anthocyanins contents (TA) in the extruded products occurred during extrusion cooking. However, extrusion cooking retained antioxidant capacities of the raw formulations in the extruded products. This study demonstrated the potential for the production of puffed extruded food products with improved antioxidant content from colored potatoes and pulse formulations.

The flavors of bread, popcorn, aromatic rice (such as Basmati and jasmine), and tortillas are among the most popular and desirable of all foods. The appealing and attractive flavors of these foods are largely due to 2-acetyl-1-pyrroline and 2-acetyltetrahydropyridine. These two compounds have popcorn-like, cracker-like and roasty odors and are key contributors to the flavors of cereal products. In this study we synthesized and characterized a new flavor compound, 2-formyl-1,4,5,6-tetrahydropyridine. This compound has a pleasant cracker-like odor. Further studies are needed to determine if this compound occurs in food and, if so, to quantify its odor contribution.


4.Accomplishments
1. Novel energy drinks from dried peas. To address the nutritional and/or health limitations of commercially available energy drinks and soybean-based drinks, we developed beverages using rice and pea proteins, gums, sweeteners, and different flavors mixed with deionized water. The drinks had a smooth, silky consistency similar to those of soybean-based drinks. Additionally, the drinks had an acceptable flavor and were stable after ten days under refrigeration temperature. This study represents the initial findings in the development of new, value-added products from dry pea-based proteins. It brings useful tools and processes that will help to achieve the final objective in creating an innovative vegetable protein-based drink that would meet consumer needs for a healthy, nutritious, tasty, stable, safe and convenient product. It will also bring economical benefits to growers and processors of dry pea and other pulses in the U.S.

2. Flavor constituents in domestic and imported black olives. In collaboration with UC Davis and the UC Davis Olive Center, we characterized flavor constituents of domestic and imported black olives. Domestic olives had a similar profile of flavor constituents while imported olives had a very different composition of flavor compounds. There was strong evidence that imported olives (from Spain, Egypt and Morocco) had been fermented by yeasts and/or molds prior to processing. There were no signs of fermentation in the domestic olives. All of the imported olive samples contained moderate to high levels of styrene (up to 500 ppb) while styrene was not detected in the domestic samples. These results are critical for ensuring the safety and acceptability of our food supply.


Review Publications
Cool, L.G., Takeoka, G.R., Vermillion, K. 2011. Volatile non-terpenoid hydrocarbons from Ligusticum grayi roots. Phytochemistry Letters. 4:158-160.

Cui, L., Pan, Z., Yue, T., Atungulu, G.G., Berrios, J.D. 2010. Effect of ultrasonic treatment of brown rice at different temperatures on cooking properties and quality. Cereal Chemistry. 87(5):403-408. doi: 10.1094/CCHEM-02-10-0034.

Berrios, J.D. 2010. Extrusion cooking: Legume pulses. In: Helman, D.R., Moraru, C.I., editors. Encyclopedia of Agricultural, Food, and Biological Engineering. 2nd edition. New York, NY: Taylor & Francis Group. p. 453-464.

Last Modified: 7/24/2014
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