Encapsulation of Yoghurt Starter Using Starch as a Filler Through Emulsification Method

Abstract

The viability of starter culture (Streptococcus thermophilus and Lactobacillus bulgaricus) in yoghurt declined during storage. Therefore, it needs protection to prevent this condition by encapsulation. The encapsulation has been conducted by the emulsification method. This research aimed to determine the best encapsulant which could protect starter culture and to investigate the characteristic of yoghurt produced from the starter using selected encapsulant. The emulsification method was developed by mixing encapsulant materials (maize resistant starch and maltodextrin) with vegetable oil (canola oil containing 0.5% tween 80%), in a ratio by 1:2:2. Subsequently, 0.1% inoculum (cultivated from initial of log phase) was added. The three composition of encapsulant materials were alginate 2%: Maize resistant starch 2%; alginate 3%: Maltodextrin 1%; and alginate 4%. The best encapsulant was alginate 3%: Maltodextrin 1%. This encapsulation increased the viability of the bacteria by 0.27 log CFU/g (on wet beads) and 5.78 log CFU/g (on dry beads) compared to the free cell. Yoghurt produced using a starter with encapsulant 3% alginate: 1% maltodextrin was more acidic than from the free cells, but it was still lower than commercial starter. Based on hedonic test, yoghurt produced from the best encapsulant was not significantly different from the commercial starter.