Colour and Fatty Acids Analysis of Fermented and Canned African Oil Bean (Pentaclethra macrophylla Benth) Seeds

Abstract

The variations in the colour and fatty acid profiles as influenced by the processing steps and changes in canning media during thermal processing of fermented African oil bean (Pentaclethra macrophylla Benth) seeds were investigated. The seed cotyledons were prepared as slices and fermented at 30^oC for 72 h. The fermented product was then filled into cans containing the selected media and processed using conventional canning procedures. Cooking and canning steps slightly darkened the light brown colour of the cotyledons. However, overall, thermal processing did not significantly (p > 0.05) affect the colour profile of the fermented seed product ‘ugba’ as shown from a*/b* ratios, hue and chroma values. Although fermentation significantly (p > 0.05) affected the composition and concentrations of fatty acids in the seed oil, the effect of canning of the fermented seed product in three different media (tomato sauce, refined groundnut oil and brine solution) on the fatty acid profiles of the seed oil was not significant (p > 0.05). Linoleic acid, which was the major fatty acid in the raw seed oil (67.20 wt.-% of total fatty acids), increased significantly during fermentation, but further thermal processing in lacquered cans did not affect the fatty acids profile.

Keywords: Oil bean seed; fermented product; thermal processing; colour; fatty acids