Physiochemical Properties of Soy and Kinema Flours and Their Application in Formulation of High Protein Biscuits

  • A. K. Shrestha Department of Food Science and Technology, The University of New South Wales, Sydney 2052
  • Athapol Noomhorm Agricultural and Food Engineering Program, Asian Institute of Technology, PO. Box 4, Klongluang, Pathumthani, 12120

Abstract

Kinema was prepared by natural fermentation of soybeans.Tentatively identified bacillus strains were isolated from the traditional product and used for making kinema in the laboratory Kinema prepared by both methods was dried and ground to fine flour. Full fat and low fat soy flours were also prepared. Chemical analysis showed little change in protein and total fat content during fermentation, whereas free fatty acids increased substantially. Crude fiber and total sugar contents were reduced with a simultaneous increase in reducing sugars. Whereas water and oil retention capacity, gelation, foaming capacity and urease activity of kinema flours were lower than soyflours, emulsifying activity bulk density, viscosity and particle size were higher for kinema flours. Nitrogen solubility index was high in kinema flours at 64.3% and 66.0% for traditional and pure culture kinema products, respectively Kinema flours were significantly (P<0.05) darker, more red and yellow than soyflours. Soy and kinema flours were incorporated at 15% level into biscuits formulation. Protein content of all products was more than 17%.There was little difference in the proximate composition of the four types of biscuits prepared except for biscuits supplemented with low-fat soy flour Incorporation of kinema contributed red and yellow colour to the corresponding biscuits. Kinema supplementation resulted in decreased hardness but increased weight and spread ratio in fortified biscuits. Evaluation of sensory characteristics showed greater acceptance of kinema-supplemented biscuits in comparison to full fat soy flour-supplemented biscuits.