30C-4 |
Characterization of proteins in fleshes and seeds of bitter gourds |
R. Cai1, N. S. HETTIARACHCHY1, and M. Julaluddin2. (1) Department of Food Science, University of Arkansas, Fayetteville, AR 72704, (2) Department of Agriculture, University of Pine Bluff, Pine Bluff, AR 71611 Bitter gourd has excellent medicinal value and been used as native medicines in Asia and Africa. It has been reported that bitter gourd contains a polypeptide p-insulin similar to bovine insulin in normalizing the blood sugar level, and, therefore, has been used as a folk medicine for diabetes. Although the value of bitter gourd is realized, information on its protein constituent is limited. More detailed investigations on the bitter gourd proteins are needed in order to provide information for quality improvement and value-added product processing. Our objective was to characterize the bitter gourd protein components during the physical separation and aqueous fractionation of flesh and seed components. Three bitter gourd varieties were studied, including an Indian Green, an Indian White, and a Chinese variety grown in Arkansas. Bitter gourd fleshes and seeds were separated manually and analyzed for protein and moisture contents. The fleshes and seeds were fractionated into water soluble and insolube factions. Protein content was determined using Kjeldahl method. Bitter gourd proteins were characterized using gel electrophoresis. Protein content of seeds ranged from 16.9% to 19.7% and those of fleshes from 6.6% to 9.5%. Protein content of water soluble fractions from the fleshes ranged from 5.7% to 10.3%, and those of water soluble fractions of seeds from 19.0% to 22.9%. While fleshes had a similar moisture content, approximately 94%, seeds had varied moisture contents depending on degree of maturation. Electrophoresis indicated that proteins in seeds of three bitter gourds had a simple composition with four major bands at around 50, 48, 40 and 28 kDa. These results indicate that seeds carry the major proportion of proteins in bitter gourd. Seeds also contain more water soluble proteins than fleshes. The simple protein composition shown with gel electrophoresis suggests a uniform melting and crystallization characteristics of bitter gourd proteins.
Session 30C, Food Chemistry: Proteins
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