RESUMO
Background and Objectives: The use of Bacillus probiotics is an interesting way for manufacturing healthier meat and meat products as functional foods and also a valuable solution for overcoming the constraints related to the stability of probiotic strains of Lactobacillus and Bifidobacterium during processing and storage of foods. This work is an attempt to investigate the influence of common household cooking methods on the viability of Bacillus coagulans and Bacillus subtilis as probiotic sporeformers inoculated into cooked sausages
Materials and Methods: After preparation of the final suspensions of Bacillus coagulans ATCC 31284 and Bacillus subtilis var. Natto ATCC 15245 spores, they were supplemented in the sausage samples with different meat types and percentages. The inoculated cooked sausages were then submitted to common household cooking methods, i.e. boiling, microwaving, and deep fat frying. Enumeration of the studied spores was carried out on trypticase soy agar after exposure to a heat shock at 68°C for 20 min. One-way analysis of variance [ANOVA] of SPSS-20 was used for statistical analysis of the data. A Taguchi L9 experimental design comprising 3 variables and 3 levels was performed using MINITAB-17 to determine main effects of the parameters of household cooking process
Results: The results obtained in this study showed that boiling, followed by microwaving and deep fat frying, had the greatest viability and recovery of the studied spores supplemented in the cooked sausages, respectively [P < 0.05]. Furthermore, results of the Taguchi experimental method revealed that the type of Bacillus probiotics, followed by the formulation of cooked sausages and the method of household cooking of cooked sausages had main effects on the concentrations of the spores examined, respectively
Conclusions: The information provided here suggests that boiling as a common household cooking method retained maximum viability and recovery of the studied Bacillus probiotics supplemented in the cooked sausage samples. Besides, the type of spores was the principle parameter, which had a critical effect on the response [i.e. concentrations of the studied Bacillus probiotics]
RESUMO
Background and Objectives: The purpose of the present study was to investigate effects of various heat shock conditions and fast freezing and subsequent thawing on the viability and recovery of Bacillus coagulans and Bacillus subtilis as probiotic Sporeformers, and also to compare spore plate and microscopic counts
Materials and Methods: After preparing the final suspensions of B. coagulans and Bacillus suhtilis subsp. Natto spores, they were spread-plated before and after fast freezing treatment [-70°C for about 1 min]. Heat shock treatments of the spores were carried out at 68°C for 15, 20, and 30 min as well as at 80°C for 10 and 15 min. Concentrations of the examined probiotic Sporeformers were determined simultaneously by plate enumerations and microscopically determined counts. Student's t-test and one-way analysis of variance [ANOVA] of SPSS were used for statistical analysis of the data. Analysis of DoE results was carried out using Minitab
Results: The results presented here show that the highest recovery rates for B. coagulans [14.75 log CFU/mL] and B. subtilis spores [14.80 log CFU/mL] were under a heat shock condition of 68°C for 20 min in nutrient agar [p<0.05]
In addition, the survival rates of B. coagulans and B. subtilis spores under the fast freezing and subsequent thawing condition were about 90% and 88%, respectively. Plate counts differed significantly from counts determined microscopically, with differences of almost 0.5 and 0.8 log for B. coagulans and B. subtilis spores, respectively [p<0.05]
In addition, DoE results of the study revealed that both factors of spore count method and only freezing factor in fast freezing treatment have a significant effect on concentrations of the spores examined [p<0.05]
Conclusions: Heat shock conditions, freezing and subsequent thawing circumstances, and plate counts or enumerations determined microscopically have significant influences on the viability of probiotic Sporeformers and should be considered in determining of their accurate concentrations