Evaluation of the effects of canning variables on the mineral composition of canned cowpeas ( Vigna unguiculata l. Walp) using multi-response analysis.

This study aims to investigate the effects of canning variables (cooking time, storage time, volume of vinegar, salt and sugar) on the mineral composition of canned cowpea ( Vigna unguiculata (L.) Walp) and which conditions provide optimised preservation of the mineral content of the grains. Different formulations of canned cowpeas were produced following two levels factorial experimental design using five variables. A set of 11 different formulations were evaluated using the desirability function with essential minerals (Ca, Cu, Fe, Mn, Mg, P and Zn) as the response. The optimal multi-response conditions for higher mineral retention were: 360 days of storage at 30 ± 5°C (ST2), 30 ml of vinegar, 9.0 g of NaCl, 18 min of cooking time, and 9.0 g, 19.5 g or 30 g of sugar (the effect of the sugar content at the evaluated range was not significant at 95% confidence level).