Nutritional Composition of Canavalia ensiformis (L.) (Jack Beans) as Affected by the use of Mould Starter Cultures for Fermentation.

Abstract

In order to investigate the role of the individual mould strains in the improvement of the nutritional status of jack beans during natural fermentation. The part played by individual mould strains was investigated using each as a starter culture inoculum, using pressure-cooking as the mode of thermal treatment. One hundred gramme of ground, 40 min, pressure cooked samples were inoculated with the single starter cultures under aseptic condition using 1 mL of each inoculum and the samples were homogenized using a sterile scapula after which fermentation was allowed to take place under controlled environment of temperature of 30±3°C for 14 days. Physical sensory changes, fermentation parameters, proximate and antinutritional composition were determined during fermentation. The total titratable acidity of the fermenting substrates varied between 0.07% for N. crassa fermented substrate to 0.26% for R. oryzae fermented substrate. While there was a general decrease in value for the pH of the fermenting substrates from 6.6 to 5.9. Proximate analysis revealed that the protein content of substrates increased from 26.21 g 100 g-1 in the control to 33.51 g 100 g-1 with N. crassa as the inoculum, while the fat content decreased from 11.95 g 100 g-1 in the control to 1.95 g 100 g-1 in the substrate fermented with A. niger, respectively. The mineral composition showed an increase in magnesium, sodium, potassium and iron compared with the control (30.07, 18.51, 23.51 and 0.00 μg g-1, respectively). The antinutrient composition revealed that both the canavanine and phytate content of the fermented substrates decreased significantly from 0.79 mg g-1 (control) to 0.53 mg g-1 (A. niger fermented substrate) and 5865.60 mg 100 mg-1 (control) to 1352.60 mg 100 g-1 (A. niger fermented substrate), respectively. Therefore, the use of single starter culture mould fermentation can be used to improve the nutritional quality of Canavalia ensiformis L.