Optimization of the Growth Rate of Probiotics in Fermented Milk Using Genetic Algorithms and Sequential Quadratic Programming Techniques

Ming-Ju Chen,Kun-Nan Chen,Chin-Wen Lin

doi:10.5713/ajas.2003.894

Abstract

Prebiotics (peptides, N-acetyglucoamine, fructo-oligosaccharides, isomalto-oligosaccharides and galacto- oligosaccharides) were added to skim milk in order to improve the growth rate of contained Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium longum and Bifidobacterium bifidum. The purpose of this research was to study the potential synergy between probiotics and prebiotics when present in milk, and to apply modern optimization techniques to obtain optimal design and performance for the growth rate of the probiotics using a response surface-modeling technique. To carry out response surface modeling, the regression method was performed on experimental results to build mathematical models. The models were then formulated as an objective function in an optimization problem that was consequently optimized using a genetic algorithm and sequential quadratic programming approach to obtain the maximum growth rate of the probiotics. The results showed that the quadratic models appeared to have the most accurate response surface fit. Both SQP and GA were able to identify the optimal combination of prebiotics to stimulate the growth of probiotics in milk. Comparing both methods, SQP appeared to be more efficient than GA at such a task. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 6 : 894-902)

Highlights

In recent years, there has been a worldwide increase in interest in the addition of intestinal bacterial species
The present work has developed a prediction model for the growth rate of probiotics by using RSM, this model determining the effect of prebiotics on the viability of probiotics when in combination
Fitting the model: Five prebiotics, which were defined as the designed variable, were mixed with milk in order to attempt to improve the growth rate of L

Summary

Introduction

There has been a worldwide increase in interest in the addition of intestinal bacterial species A number of substances are well known to improve the growth of probiotic bacteria, eg the supplementation of milk with a combination of casitone, casein hydrolysate and fructose stimulates the growth of L. acidophilus (Saxena et al, 1994). Such stimulation in growth is suggested to arise due to an enhanced availability of simple sugars, mainly glucose and fructose, and minerals which have been demonstrated to be growth promoters of L. acidophilus

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Conclusion