Effect of process method on the energy and protein content, antinutritional factors and in-vitro protein digestibility of cowpea milk ( Vigna unguiculata)

Abstract

Milk was obtained from two cultivars of cowpeas ( Vigna unguiculata) by hot water extraction, cold water extraction or boiling for 10 min before cold water extraction. The energy content of the extracts for both cultivars and extraction methods ranged (per 100 g) from 25·0 to 31·0 kcal (1 cal = 4·2 J), protein from 1·0 to 2·0 g, sugars from 0·5 to 3·8 g and iron from 0·9 to 1·5 mg. In-vitro digestibility coefficient ranged from 60·5 to 81·8%, trypsin inhibiting units/ml from 4·5 to 6·1, while phytic acid ranged from 61·8 to 80·5 μg/100 g. Milk yield was higher in the small white cultivar than the big white. The beany taste was completely absent in the hot water extraction process while it was slightly perceptible in the pre-boiled process and distinct in the cold water extraction.