The Use of Lactic Acid Bacteria Starter Culture in the Production ofNunu, a Spontaneously Fermented Milk Product in Ghana

Abstract

Nunu, a spontaneously fermented yoghurt-like product, is produced and consumed in parts of West Africa. A total of 373 predominant lactic acid bacteria (LAB) previously isolated and identified fromNunuproduct were assessedin vitrofor their technological properties (acidification, exopolysaccharides production, lipolysis, proteolysis and antimicrobial activities). Following the determination of technological properties,Lactobacillus fermentum22-16,Lactobacillus plantarum8-2,Lactobacillus helveticus22-7, andLeuconostoc mesenteroides14-11 were used as single and combined starter cultures forNunufermentation. Starter culture fermentedNunusamples were assessed for amino acids profile and rate of acidification and were subsequently evaluated for consumer acceptability. For acidification properties, 82%, 59%, 34%, and 20% of strains belonging toLactobacillus helveticus, L. plantarum, L. fermentum, andLeu. mesenteriodes, respectively, demonstrated fast acidification properties. High proteolytic activity (>100 to 150 μg/mL) was observed for 50%Leu. mesenteroides,40%L. fermentum,41%L. helveticus, 27%L. plantarum,and 10%Ent. faeciumspecies. In starter culture fermentedNunusamples, all amino acids determined were detected inNunufermented with single starters ofL. plantarumandL. helveticusand combined starter ofL. fermntumandL. helveticus. Consumer sensory analysis showed varying degrees of acceptability forNunufermented with the different starter cultures.