ABSTRACT
Abstract Using the non-linear regression model, the present study aims to develop sample mathematical models for the microbial flora by utilization of the antimicrobial effects of rosemary (Rosmarinus officinalis) extracts at different concentrations (0.5, 1, 1.5, and 2%) on the raw chicken mince. For this purpose, 5 experimental groups were established for each plant extract. The samples (100 g each) treated with plant extract at different concentrations were vacuum-packaged under aseptic conditions. The packaged samples were kept in refrigerator (4ºC). The microbiological analyses of (total mesophilic aerobic bacteria, total coliform group bacteria, S. aureus, total yeast-mold, and total psychrophilic bacteria) were performed on 0th, 1st, 3rd, 5th, 7th, and 10th days of storage. When compared to the control group the treatment with RE resulted in a decrease in the microbial numbers by 2.5 log units for TMAB number, by 3.5 log units for S. aureus number, by 3,5 log units for TMY number and by 1.5 log units for TP bacteria on the final day of storage. In establishing the model, the plant extract and storage period were used as variable parameters, whereas the shelf-life was used as output parameter. The changes in shelf-life of raw chicken minces by storage period and extract concentration were modeled, the compliance of obtained mathematical models was tested using Variance Analysis Method (ANOVA) and regression and determination coefficients (R2) were determined. After determining their compliance of models based on R2 values, the estimated values and real values were compared. As a result of study, it was determined that R2 values of raw chicken mince models by total mesophilic aerobic bacteria, S. aureus, total coliform bacteria, total yeast/mold, and total psychrophilic bacteria during the storage period were found to range between 0.743 and 0.978 and the models representing the microbial change were found to have a high level of compliance.
ABSTRACT
Abstract In this study, we aim to determine the shelf life of dried and ready to use-powdered soup samples obtained from different types of fish species such as Rainbow trout (Oncorhynchus mykiss), sea bream (Sparusaurata L.) and sea bass (Dicentrarchuc labrax). For this purpose, the chemical (moisture, protein, fat, carbohydrate, ash, pH, Thiobarbituric acid (TBA), Total volatile basic nitrogen (TVB-N), microbiological (total mesophilic aerobic bacteria, total yeast and mold, total coliform, Staphylococcus spp. and Salmonella spp.) and sensory properties of fish soup samples were determined during 6-month storage period. The pH, TBA and TVB-N values of all samples increased during the storage period, but these values were within the consumption limits. Additionally, the microbiological properties of all fish soup samples were found within the consumption limits during storage. As a result, a product has been obtained with high nutritional value and rich with regard to protein, oil, and minerals by adding the fish meat to soup samples. It has been determined that the product quality and shelf life significantly increased by using the boiled product for the production of soup samples.