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.