Scientific journal

50 2011

Journal of Food and Nutrition Research
Summary No. 4 / 2011

Functional and some nutritional properties of an isoelectric protein isolate from Mexican cowpea (Vigna unguiculata) seeds
Journal of Food and Nutrition Research, 50, 2011, No. 4, s. 210-220

David Betancur–Ancona, Faculty of Chemical Engineering, Autonomous University of Yucatan, Periférico Norte Km. 33.5, Chuburná de Hidalgo Inn, Mérida, 97203 Yucatán, Mexico. E-mail:; tel.: 946-09-56; 946-09-81

Summary: Mexican cowpea (Vigna unguiculata) is a regionally adapted variety that differs from cowpea varieties in morphology, physiology and possibly some chemical characteristics. Like other varieties, it has potentially good nutritional quality. An isoelectric protein isolate was extracted from seeds harvested in Yucatan State, México, for evaluation of functional and nutritional properties. Protein content was 82.8% and solubility pattern was classical with an isoelectric point (IP) at pH 6. Water-holding capacity (245%) and oil-holding capacity (231%) were balanced. Foam capacity was best (133–190%) at extremely acid and alkaline pH, but low at pH values near neutral or at IP. Foam stability was low at all studied pH values. Emulsifying capacity (45%) was independent of pH value. Emulsion stability was generally low, but improved slightly at alkaline pH. Available lysine content was 64 g?kg-1 of protein, although sulfur amino acids were the first limiting factor. True digestibility was good (88.8%), but the protein efficiency ratio was low (1.24) classifying the isolate as having low nutritional value. The protein isolation method applied here clearly improved the functional and nutritional properties of raw Mexican cowpea seeds, but the isolate would require supplementation with other nutrients.

Keywords: Mexican cowpea; Vigna unguiculata; protein isolate; functional properties; nutritional properties

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