Production of Nata de Coco from Low-quality of Langsat (Lansium domesticum Corr.) and Mangosteen (Garcinia mangostana Linn.) in Narathiwat province

Abstract

This research aims to produce bacterial cellulose from low-quality langsat (Lansium domesticum Corr.) and mangosteen (Garcinia mangostana Linn.), in Narathiwat Province, using Acetobacter xylinum TISTR 893. This study investigated the optimal ratio between the two types of fruit juices and the relevant factors that promote bacterial growth and maximize bacterial cellulose production. The experimental results indicated that 30 % (v/v) langsat juice and 10 % (v/v) mangosteen juice were the most suitable concentrations, as determined by the weight of the bacterial cellulose. The yields were 25.53 ± 0.11 g/100 mL and 23.24 ± 0.42 g/100 mL, respectively. In addition, an examination of various factors in the culture medium, including total soluble solids, ammonium phosphate concentration, and optimal pH, showed that 9 °Brix in langsat juice and 12 °Brix in mangosteen juice provided the most favorable conditions for bacterial growth, resulting in maximum bacterial cellulose yields of 24.50 ± 0.03 and 22.90 ± 1.04 g/100 mL. 0.5% (w/v) ammonium phosphate concentration combined with an initial pH of 4.0 in the culture medium was found to be optimal for bacterial growth. Under these conditions, the bacterial cellulose weights were 23.29 ± 0.20 and 24.62 ± 0.20 g/100 mL, and 25.53 ± 0.22 and 27.31 ± 0.10 g/100 mL, respectively. Subsequently, the quality of bacterial cellulose produced under optimal culture conditions was analyzed. The results showed increased production, with yields of 30.64 ± 0.56 g/100 mL from langsat juice and 30.54 ± 0.36 g/100 mL from mangosteen juice. Physical examinations showed that bacterial cellulose from langsat juice exhibited a yellowish-brown color, whereas that from mangosteen juice was off-white. The gel strength of cellulose from both fruit juices was similar, indicating comparable textural quality.