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United States Department of Agriculture

Agricultural Research Service

Research Project: CHARACTERIZATION AND CONTROL OF NUTRITIONAL AND SENSORY PROPERTIES OF RAW AND PROCESSED GRAINS, LEGUMES, AND VEGETABLES

Location: Healthy Processed Foods Research

2010 Annual Report


1a.Objectives (from AD-416)
Isolate and characterize biologically active constituents in grains, legumes, nuts and vegetables, and their co-products. Optimize processing and storage conditions to enhance flavor and health-promoting phytonutrients. Add value to grains, legumes, and/or vegetables by extrusion technology using processing parameters and texture-modifying ingredients to control or enhance nutritional, textural and sensory properties.


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 corn, rice, potato, tapioca and apple will be added to legume flours to enhance the physiochemical properties of the extruded products. 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. Biosynthetic precursors of aroma compounds such as glycosides will be identified and model systems will be used to explore precursors of some aroma compounds formed during processing. The investigators will develop and apply capillary electrochromatography (CEC) to rapidly and efficiently characterize phytonutrients such as carotenoids in foods. Phytonutrients will be separated, characterized and quantified using HPLC-DAD, HPLC-MS and proton and carbon NMR spectroscopy. Antioxidant activity will be measured by the ability of extracts of specific constituents to scavenge the free radical DPPH and the ability to inhibit the oxidation of methyl linoleate and hexanal.


3.Progress Report
Novel value-added, shelf stable, tasty, and convenient snacks and cereal breakfast-type products, containing legumes, wheat, apple, and potatoes, and their fractions, were developed using innovative formulations and extrusion processing conditions in collaboration with scientists from Washington State University. The novel products contained high content of natural antioxidants and about 2-3 times more total dietary fiber than most popular snacks and breakfast cereals in the market. They also had a desirable crunchy texture and were highly acceptable to a sensory panel. The technology and products developed under this research project will be submitted as a Continuation-in-Part (CIP) to filed invention entitled “Extruded legumes”, Patent Serial No. 11/641,318, for which one national company and one international company have applied for non-exclusive license rights. Additionally, we started collaborating with a commercial cooperator interested in marketing the novel extruded lentil snack products. The research is expected to lead to commercial value-added lentil, dry pea and garbanzo based products that will help growers to compete favorably in international markets and to establish new domestic market opportunities.

The tomato is the second largest vegetable crop in dollar value in the U.S. with a fresh market value of $1.6 billion in 2005. Using chemical and sensory analyses, the nineteen most important odorants responsible for fresh tomato flavor were identified and quantified. It was shown that the differences between highly appetizing and less appetizing tomatoes were due to variations in the concentrations of certain flavor compounds. Higher amounts of the (E,E)- and (E,Z)-2,4-decadienal isomers and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol®) had a positive influence on preference, whereas high concentrations of methional, phenylacetaldehyde, 2-phenylethanol or 2-isobutylthiazole had a negative influence. This fundamental knowledge will help plant breeders and growers to select cultivars with the highest consumer preference.

We quantified the antioxidant activity, phenolic, and anthocyanin concentration in fifteen rhubarb cultivars. Rhubarb cultivars had high phenolic concentrations ranging from 673 to 3540 mg/100 g DW. These concentrations are much higher than the levels found in America’s number one vegetable, the potato (concentrations ranging from 100 to more than 1500 mg/100 g DW). Studies have indicated that phytonutrients, especially phenolic compounds, have high free-radical scavenging activity, which helps to reduce the risk of chronic diseases such as cardiovascular disease, cancer and age-related neuronal degeneration. Rhubarb cultivars were found to have very high antioxidant activity with values ranging from 491 to 1820 umol Trolox equivalents/g DW. This information on the phenolic content and antioxidant activity of rhubarb cultivars will be helpful in increasing awareness of consumers regarding the level of beneficial phytochemicals present in this vegetable. This information will also be beneficial to breeders seeking to increase the antioxidant activity and concentration of phytonutrients in rhubarb.


4.Accomplishments
1. New value-added lentil products. In the U.S., 1 in 133 consumers is considered to be allergic to gluten (Celiac disease). According to the USDA, the gluten-free market is currently valued at approximately $1.7 billion and is expected to increase to $2.5 billion by the year 2012. Lentil growers are in need of new value-added products in order to compete effectively with imported lentils. Using extrusion technology, novel, lentil-based snacks rich in gluten-free dietary fiber, protein, and antioxidants were developed by ARS researchers in the Processed Foods Research Unit, Albany, CA, in collaboration with Washington State University in support of growers represented by the U.S. Dry Pea and Lentil Council. The developed value-added lentil-based snacks received great acceptance by a sensory panel. The products and technology developed under this accomplishment will be submitted as a Continuation-in-Part (CIP) to filed invention entitled “Extruded legumes”, Patent Serial No. 11/641,318. The commercialization of value-added lentil-based gluten-free products will benefit a large number of consumers allergic to gluten and benefit U.S. growers and processors by increasing demand for this commodity and improving their ability to compete in the global marketplace.

2. Antioxidant activity and phenolic content of raisin grape cultivars and selections. Ten new raisin grape selections and six raisin grape cultivars were studied for their antioxidant activity and total and individual phenolic content. One of the new selections, A95-27 had a concentration of total phenolics more than three times higher than Thompson Seedless grapes, the most widely used grape variety in raisin production. It was noteworthy that three of the new selections, A56-66, A95-15 and A95-27, had antioxidant activities more than three times higher than Thompson Seedless grapes. The same selections had from 9 to 23 times more catechin, 19 to 57 times more epicatechin than Thompson Seedless grapes. Due to their higher antioxidant activities and higher concentrations of catechin and epicatechin compared to Thompson Seedless grapes, these three selections have the potential to be new commercial raisin grapes with improved nutritional properties.


Review Publications
Takeoka, G.R., Hobbs, C., Park, B.-S. 2010. Volatile Constituents of the Aerial Parts of Salvia apiana Jepson. Journal of Essential Oil Research. 22: 241-244.

Takeoka, G.R., Rodriguez, D.M., Dao, L.T., Patterson, R. 2010. Headspace Volatiles of Scutellaria Baicalensis Georgi Flowers. Journal of Essential Oil Bearing Plants. 12(4), 435-442.

Berrios, J.D., Morales, P., Camara, M., Sanchez-Mata, M.C. 2010. Carbohydrate Composition of Raw and Extruded Pulse Flours. Food Research International. 43: 531-536.

Breksa III, A.P., Takeoka, G.R., Hidalgo, M., Vilches, A.M., Vasse, J., Ramming, D.W. 2010. Phenolic Content of Raisin Grape Varieties and Genotypes. Food Chemistry. 121, 740-745.

Last Modified: 7/25/2014
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