Evaluation of Response Surface Methodology to Predict Optimum Growth Conditions for Lactobacillus plantarum A7 (KC 355240) in Probiotic Soy Milk Containing Essential Oil of Cuminum cyminum.

BACKGROUND A new product from soy milk, which is a combination of probiotics and essential oils, can be regarded as a functional food with new added health benefit. OBJECTIVES This study aimed to evaluation of the results of response surface methodology (RSM) in prediction of the optimum growth condition of Lactobacillus plantarum A7 (KC 355240) (LA7) cultured in soy milk enriched with different concentrations of essential oil of Cuminum cyminum in comparison with the classical growth curve monitoring method. METHODS Bacterial growth was investigated in the samples of probiotic soy milk containing three concentration levels (0.01%, 0.02% and 0.03% (v/v)) of the essential oil of C. cyminum. The experiments were repeated three times. Concentration of C. cyminum essential oil and the fermentation time were considered as factors and experiments were conducted based on a small composite design of response surface methodology. RESULTS According to the tests carried out, the optimum conditions were determined as the concentration of 0.02% (v/v) essential oil and 9 hours of fermentation. CONCLUSIONS These results were in accordance with the outcomes of classical growth curve monitoring method. There are several patents that have recently shown a diverse mix of soy milk in functional foods. Results of this study can be used in the preparation of functional products, enriched with medicinal plants.