104C-23 |
The effect of steam and water blanching on Edamame soybeans |
C. C. FONG1, M. M. McKean1, S. Prawiradjaja2, and L. A. Wilson2. (1) Food Science and Human Nutrition, Iowa State University, 2312 Food Sciences Building, Ames, IA 50011, (2) Dept. of Food Science & Human Nutrition, Iowa State Univ., 2312 Food Science Bldg., Ames, IA 50011 Edamame soybeans are immature green beans that can be consumed as a vegetable, rather than harvesting as mature soybeans. However, Edamame beans should be blanched prior to further processing and storage to improve nutritional and sensory quality. The objective of this research is to optimize the blanching process of Edamame beans and evaluate the influence of steam and water blanching on composition and quality of Edamame beans for frozen storage. The Edamame soybeans were either steam blanched in the pods in a small batch steam blancher (Dixie Canners; Athens, Georgia) or water blanched (100ºC) using a Groen electric heated kettle (Elk Grove, Illinois). Soybean cultivars IA1010, IA 2040LS and IA 3006 were harvested in the immature green stage. Pods were sorted and cleaned prior to blanching. After blanching, the Edamame beans were water cooled and packaged in zip-loc bags prior to frozen storage (-20°C). Raw and blanched Edamame beans were tested for peroxidase and catalase activities to determine the adequacy of blanching. Colors were measured using Hunter Color Difference meter (Model 6100). Texture was measured using a TAXT2. Trained panelists evaluated sensory qualities of the cultivars. The %moisture, %protein, %fat and trypsin inhibitor levels were analyzed using standard AOAC methods. The isoflavone content was analyzed using Song et al’s methods (1998). Blanching for 1 minute was sufficient to inactivate peroxidase, but it only inactivated 38% to 45% of the trypsin inhibitor. Water and steam blanching for 3 minutes or longer inhibited more than 95% of the trypsin inhibitor. Catalase was not a good measure of the adequacy of blanching. There were no significant changes in %protein, %moisture and isoflavone content for different blanching times. There was slight increased in %fat content after the beans were blanched for 1 minute.
Session 104C, Fruit & Vegetable Products: Vegetables (Processed)
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