Prebiotic efficacy of coconut kernel cake’s soluble crude polysaccharides on growth rates and acidifying property of probiotic lactic acid bacteria in vitro

Abstract

This paper reports the prebiotic efficacy of soluble crude polysaccharides (SCP) from palm kernel cake on the growth rates and acidifying property of probiotic lactic acid bacteria (LAB), Lactobacillus plantarum ATCC 8014 and Lactobacillus rhamnosus ATCC 53103, to investigate into the potential SCP of an agriculture by-product as a novel prebiotic. The highest extraction yield of SCP (2.90%) was obtained using NaOH. The extracted polysaccharides were highly soluble (>97%). The highest percentage of protein (0.63 ± 0.09%) and the total carbohydrate content (55.36 ± 0.33%) were observed in NaOH-extracted SCP (SCPN) and citric acid-extracted SCP (SCPCA). Water-extracted SCP (SCPW) contained the highest percentage of glucose, whereas SCPCA demonstrated the presence of two major monosaccharides, galactose and mannose. Structural analysis of SCP showed peaks in the range of 1000–1077 cm−1, an indication of the presence of polysaccharides and alpha (α)- or beta (β)-glycosidic linkages. The degree of hydrolysis increased with the increase of pH from 5 to 8 following 4 h incubation. SCPW and SCPCA were more resistant (95%) to α-amylase as compared to fructooligosaccharides (FOS). As in the case of FOS (∼98%), SCPW (∼99%) and SCPCA (∼98%) were resistant to artificial human gastric juice and their degree of hydrolysis had negative correlation with the pH. The product was found to markedly stimulate the proliferation of the tested probiotics and acid production. All the above findings are supportive of the fact that polysaccharides extracted from CKC have a vast potential to be exploited as novel prebiotic.

Keywords

• coconut kernel cake
• extraction
• solubility
• hydrolysis
• functional food