Growth characteristics of agrowaste‐immobilised lactobacilli in soymilk during refrigerated storage

Abstract

We aimed at evaluating agricultural wastes as solid supports for the immobilisation of lactobacilli in a liquid media, namely soymilk. Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733 and L. bulgaricus FTCC 0411 were immobilised on solid supports produced from durian (Durio zibethinus), cempedak (Artocarpus champeden) and mangosteen (Garcinia mangostana). The immobilised cells were inoculated into soymilk and stored at 4°C over 168 h. Soymilk inoculated with non-immobilised cells was used as the control. Immobilised cells showed higher survivability over 168 h compared to the control, accompanied by higher reduction of simple sugars and oligosaccharides in soymilk. Higher growth and higher utilisation of substrates also led to the higher production of lactic and acetic acids, which lowered the pH in soymilk compared to the control. Our results illustrated that agrowastes could be used as immobilisers to enhance the growth of lactobacilli in a liquid medium.

Bioactive property of soymilk fermented by agrowastes‐immobilized lactobacilli

“…We have previously shown that these led to increased proliferation of agrowastes‐immobilized cells in soymilk compared to free cells (Teh et al , 2009), and in the present study, this has led to increased proteolysis. Our previous studies also showed that immobilized cells had better growths at 25°C compared to 4°C and 37°C (Teh et al , 2009, 2010a, b), which was in tandem with the higher degree of proteolytic activity in soymilk at 25°C in the present study.…”

“…We have previously reported that agrowastes are efficient immobilizers for lactobacilli cells in the fermentation of soymilk. Immobilized cells showed better growth, utilization of substrates and production of short‐chain fatty acids during prolonged fermentation at different temperatures (4°C, 25°C, 36°C) compared to free cells (Teh et al , 2009, 2010a, b). However, the effect of such immobilization on the bioactivity of fermented soymilk remains unknown.…”