ABSTRACT
Developing minced-based products is a good opportunity for production of value-added products. Fish burgers are an example of an acceptable value-added fast food. In the present study, fish burgers were produced from deep flounder fish with no coating and their chemical, microbial, and sensory characteristics during storage at ?18°C for 5 months were determined periodically after thawing at 4°C. Fish burgers were produced and packaged in PVC/PE polymer bags. Microbial load [including total plate count, total coliform count, Escherichia coli, Staphylococcus aureus, and psychrotrophic bacteria], chemical characteristics [moisture, pH, total volatile base nitrogen [TVB-N], and TBA], and sensory characteristicswere were determined monthly. Data were analyzed using the SPSS for Windows program. The TVB-N and TBA values increased significantly by the end of the first and second month, respectively. After that no further statistically significalt changes occured in the former, while the latter decreased until the end of storage period, presumably due to reaction of the MDA produced with protein breakdown products and formation of new peoducts. The data also showed that pH increased significantly by the end of the first month; no changes were observed afterwards. All of the microbial counts and sensory parameters had decreased significantly [p<0.05] at the end of storage period. The best expiry time for lizardfish burgers [if stored at 18°C] is 3 months after production, and sensory evaluation is the most reliable way for predicting their shelf life
ABSTRACT
Increasing trends of overweight and obesity prevalence have prompted food producers to develop products that can enhance satiety signals. The role of short-chain fatty acids as satiety-inducing triggers seems to be of interest in this regard. The objective of this research was to investigate the impact of two process variables, namely, incubation temperature and inoculation ratio of starter bacteria, on propionic acid production in the fermented dairy beverages containing Propionibacterium immediately after fermentation and during cold storage. Fermented dairy beverage [FDB] samples were prepared using mixed cultures of Lactobacillus acidophilus and Propionibacterium freudenreichii ssp. shermanii at a ratio of 1:2, 1:4 and 1:8, repectively, at incubation temperatures of 30, 35 and 40°C, until the pH reached 4.0 +/- 0.1. Propionic, lactic and acetic acid contents of the samples were measured immediately after fermentation using HPLC. The FBD samples were refrigerated for 28 days and the concentrations of the acids in the samples with the highest propionic acid content were measured. Sensory evaluation of the samples produced was made by 11 trained panelists using the hedonic scale. The maximum propionic acid content [w/w%] was observed in a mixed culture of L. acidophilus and P. freudenreichii ssp. shermanii at a ratio of 1:4 and an incubation temperature of 30 °C. It increased from 0.75 at day 0 to 1.2 at day 28 during storage at 4°C. The incubation temperature had a statistically significant inverse effect [P<0.05] on the propionic acid production in the fermented dairy beverages