Improving shelf life and quality of Daddawa made by fermentation of soya beans and sorrel seeds from Maiduguri, north-east Nigeria

Abstract

Daddawa is a Hausa name for a fermented product made from seeds of plants such as soya bean, locust bean, baobab and castor seeds. This product serves as flavour enhancers in soups in many homes in Nigeria. Sorrel seeds are less competitive sources of amino acids and proteins that is cultivated all year round in many parts of northern Nigeria. This study evaluated the biochemical properties of a fermented daddawa made from combination of soybeans (Glycine max) and sorrel (Hibiscus sabdariffa) seeds (3:1 and 1:3 ratios). Both combinations resulted in daddawa product with significantly higher (p< 0.05) soluble proteins, amino acids and titrable acidity relative to the unfermented sample. The product made from the 3:1 soybeans and sorrel seed combination ratio had the highest concentration of amino acid (29.0 ± 1.0 mg/g sample) at 60 h of fermentation while those made from the 1:3 ratio had the highest amino acid concentration (32.0 ± 1.0 mg/g sample) at 36 h. Reducing sugar concentrations were significantly lower (p < 0.001) in the fermented daddawa product compared to the unfermented sample for both combinations. Storage with vitamins C and E significantly decreased (p < 0.001) the levels of soluble proteins and amino acids in the product made from the 3:1 soybeans and sorrel seed combination. The vitamin containing stored  daddawa product had significantly higher (p < 0.05) titrable acidity concentration. This study has shown the addition of vitamin C and E on daddawa made from a combination of soya bean and sorrel seeds to be inadequate in preserving nutrients during storage.