FABRICACIÓN DE YOGUR CON BACTERIAS INMOVILIZADAS YOGURT MANUFACTURE WITH IMMOBILIZED CELLS FABRICACIÓN DE IOGUR CON BACTERIAS INMOBILIZADAS

Abstract

The present work studies the behaviour of a bioreactor of immobilized cells for fermentation of bovine milk with the idea of yoghurt production. Indeed the bacterias used were Streptococcus salivarius ssp thermophylus and Lactobacillus delbruecki ssp bulgaricus (commercial yoghurt bacterias). The bioreactor was made by entrapping bacterias into a low metoxyl pectin gel that was supported on a concentric tubular stainless-steel mesh.In order to study the yield in terms of the temperature and the recycle rate of flow a factorial experimental design was utilized.The process was characterized in terms of the lactose consumption and the latic acid production by finding the specific rate of growth µ and the yield factors Y P/S and Y X/S .The study shows that µ remains steady when altering the experimental design parameters, in fact it is 1 h -1 . The yield Y P/S ranges between 0.16 and 0.43 g g -1 whereas Y P/S increases significantly with the variation of temperature and the rate of flow.To the light of the results it is clear that the experimental device can be optimized and its implementation to the yoghurt production would reduce dramatically the time spent.