Extrusion yields legume snacks.

You can find biologically active constituents in grains, legumes, nuts and vegetables, and their co-products. Now, USDA-ARS scientists have developed nutritious snacks from garbanzos, lentils, dry peas and beans.

The researchers have created novel healthful treats that can come in a variety of shapes, ranging from crisp bits to tubular puffs. And they are seeking a patent for the technology that led to the low-sodium, low-fat, cholesterol-free foods. The snacks are also rich in protein and dietary fiber. The research may help adults and children get the amounts of vegetables recommended by the Dietary Guidelines for Americans.

Some pre-market products have already been taste-tested by about 500 volunteers, most of whom gave the foods their approval. One snack made of crisp, fully-cooked garbanzos is ready to eat out-of-hand or could be tossed with a salad of leafy greens, sprinkled on a bowl of hearty soup, or added to traditional party mixes.

The scientists used a standard twin-screw extruder to make the snacks. The advantage of extrusion processing: the equipment is energy-efficient, fast and versatile, combining several steps including mixing, cooking, shaping and other processes needed to convert legume flours into appealing snacks. The scientists were able to determine the extrusion processing speeds, heating temperatures, amounts of moisture and formulations that can create consistent, desirable textures and tastes from legume flour.

In this and related work, the investigators generally are harnessing extrusion technology 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, are being optimized. Ingredients from corn, rice, potato, tapioca and apple are being 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, the researchers are undertaking qualitative and quantitative studies on the agricultural products before and after processing. Impact flavor constituents are being 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. The investigators are applying capillary electrochromatography to rapidly and efficiently characterize phytonutrients such as carotenoids in foods. Phytonutrients will be separated, characterized and quantified.

Further information. Jose Berrios, USDA-ARS Processed Foods Research, Western Regional Research Center, Room 0204, 800 Buchanan St., Albany, CA 94710; phone: 510-559-5652; fax: 510-559-5787; email: jberrios@pw.usda.gov.