15C-19 |
Viscous properties of taro flour extruded with whey proteins to simulate weaning foods. |
C. I. ONWULATA and R. P. Konstance. USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598 Taro flour was extruded with whey protein concentrate, whey protein isolate or lactalbumin, to derive blends containing 20% protein to simulate the protein content of most weaning foods. Taro is derived from the corm of Colocasia Esculenta, a root tuber grown in the tropical regions of the world including Hawaii. Taro flour is unique because of its extremely small particle size (1~ 5 micron) and high mucilage content, making it a possible replacement for corn or wheat starch in weaning foods. We determined the viscous properties of taro flour and whey protein blends before and after extrusion cooking. Extrusion processing temperatures were from100 to 130 °C and feed moisture was held constant at 18%. The extrudates were pulverized and made into powders which were dehydrated to make paste. Viscosities of the feed and extrudates were determined using a Rotovisco Analyzers (RVA) to determine peak, final, and breakdown viscosities. Water solubility and absorption indices were also determined. Extrudates made from taro containing whey products expanded more than taro alone, and were easier to grind into powders which rehydrated readily in water to form pastes. Before extrusion, the peak viscosities of the blends were 5000, 2600, 1600, 1600 cP for taro flour, taro with WPI, taro with WPC, or taro with LAC respectively. After extrusion cooking, the viscosities for taro flour, taro with WPI, taro with WPC, or taro with LAC were 110, 65, 70 and 90 cP, respectively. Taro extrudates without protein absorbed the most water, and were more soluble than products containing whey proteins or LAC. The consistency of extrusion cooked taro flour and whey protein blends were characteristic of weaning foods, but the inclusion of whey proteins reduced peak viscosities.
Session 15C, Dairy Foods
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