59D-22 |
Characterization of soybean protein b-conglycinin and glycinin of selected varieties |
K. A. KHATIB1, T. J. Herald1, and P. M. Muino2. (1) Dept. of Animal Sciences & Industry, Kansas State Univ., Call Hall, Manhattan, KS 66506, (2) Dept. of Chemistry, Mathematics & Physical Sciences, Saint Francis College, PO Box 600, Loretto, PA 15940 During the last decade, soybean product consumption increased due to soy health factors and consumer preference. Soy proteins tend to behave differently in food systems due to many factors. Variety and growing season are important factors to be considered in understanding the functional properties of soy proteins. The main objective of this research was to characterize b-conglycinin and glycinin from selected Kansas’s soybean varieties using chemical and physical methods. This study evaluated the efficiency of the isolation and functionality of b-conglycinin and glycinin. The soybean varieties used in the study were KS1430 (high protein), K93-90-29 (high protein), KS4997 (low protein) and Hutcheson (low protein), which were grown in two different environmental condition over two year period. The proteins were isolated using a combination of pH adjustment and physical treatments (centrifugation, fractionation, and filtration). The isolated proteins were tested for purity using SDS-Polyacrylamide Gel Electrophoresis. Thermal and functional properties were also determined. The results showed a wide range in analyses among varieties. Variations in fractional protein content (79 to 93%), thermal denaturation (78 to 94 °C) and enthalpy (-18 to -57 cal/g) were measured among varieties from the same year crop but not from different years. Moreover, similar results were found in disulphydryl (12 to 55 mmol/g) and total sulphydryl group (36 to 115 mmol/g) contents, and solubility (58 to 85%). Rheological (2 to 9 KPa), foaming (38 to 75 mL), emulsification (160 to 180 m2/g), surface tension (43 to 50 dynes/cm), and intersurface tension (4 to 12 dynes/cm) properties among the four varieties performed differently according to protein content, quality, and solubility. Knowledge of soy protein variation based on varieties and location may allow scientists to develop soybeans that may better meet the needs of food industry and enhance the quality of soy products.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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