Study on the effects of carbohydrate-protein-coconut oil on the viability of lactobacillus bulgaricus during spray drying, simulated gastrointestinal conditions and unrefrigerated storage by simplex-lattice mixture design

Abstract

Ideally, probiotics bacteria should be metabolically stable during processing, storage under unrefrigerated condition, survive passage through the upper digestive tract in large numbers for colonisation and proliferation in the large intestine, and have beneficial effects when in the intestine host. This study helps to understand the effect of feed composition towards viability of L. bulgaricus by using carbohydrate-protein-coconut oil mixtures. The encapsulation work was focused on the performance of carbohydrate-protein-coconut oil as the protective barrier. A simplex-lattice design was employed to study the effect of different feed formulation of the carbohydrate-protein-coconut oil mixtures on three response variables; the viability of L. bulgaricus after spray drying, under simulated gastrointestinal condition, and after 6 weeks storage in unrefrigerated environment. Analysis of variance and mixture design techniques were applied to identify the optimal feed composition. The optimal feed composition that results in the viability beyond the therapeutic minimum dose consisted of 30 % gum Arabic, 16.95 % gelatine and 53.05 % coconut oil. The percent of viability after spray drying, under simulated gastrointestinal condition, and after 6 weeks of storage were 4.24 %, 11.43 % and 77.36 % respectively. In conclusion, the mixture of gum Arabic - gelatine - coconut oil shows more protecting to protect against damaging of oxidative stress during storage under unrefrigerated condition.