The effect of chitosan coating and vacuum packaging on the microbiological and chemical properties of beef.

Beef is an animal food sensitive to deterioration due to its rich nutrient content. Therefore, some preservation techniques are applied. These include vacuum packaging, a modified atmosphere, a controlled atmosphere and an edible film coating. In this study, it was aimed to extend the shelf life of beef using vacuum packaging (VP) and chitosan coating with vacuum packaging (CC + VP). For this purpose, total mesophilic aerobic bacteria (TMAB), Stapylococcus aureus, lactic acid bacteria (LAB) counts, thiobarbituric acid (TBA) values and total volatile basic nitrogen (TVB-N) content were analyzed in beef obtained from local markets. As a result, it was found that the chitosan coating reduced the TMAB, LAB and TVB-N values and inhibited all S. aureus up to day 15 of storage. In addition, it was seen that the application of CC + VP was significantly more effective (p˂0.05) on the reduction of the TBA value, compared to the VP application over a long period of storage (45 days). The combined use of the two technologies is more effective on TVB-N. According to the data obtained from this study, because of the antimicrobial and antioxidant properties of chitosan, it has been concluded that it can be used as a bio-preservative in the meat industry.

Biochemical changes and sensory assessment on tissues of carp (Cyprinus carpio, Linnaeus 1758) during sale conditions.

In this study, some biochemical changes of carp (Cyprinus carpio, Linnaeus 1758) tissues were investigated. Studies have been carried out on carp which have regional economical importance. Storage temperature and time are the most important factors that affect the quality of fish during sales. It was observed that the temperature varied between 9 and 12 degrees C in sale conditions. In addition, we assumed the arrival time of the fish at the fish market to be 0 (zero) h. Biochemical analyses [malondialdehyde (MDA) levels and catalase activity] of carp tissues (muscle, liver, heart, spleen, brain) were carried out on fish which were held for 24 and 48 h, as well as on fresh fish (0 h). In addition, sensory analysis was conducted by a panel consisting of experienced judges of sensory evaluation. Statistically significant (P < 0.05) increases in MDA levels were found in liver, muscle, brain and spleen tissues when comparing the 0- and 24-h groups. But there was no statistically significant (P > 0.05) increase in MDA level in heart tissue of carp after 24 h. There was a statistically significant (P < 0.05) increase in MDA levels in muscle, spleen and heart tissues when comparing the 24- and 48-h groups. In the group examined at 24 h, it was observed that there were statistically significant differences from the 0 h group values (P < 0.05) for catalase (CAT) activity in muscle, brain, spleen and heart tissues. The decreases in CAT activity in liver and spleen tissues were found to be statistically significant (P < 0.05) between the group examined at 24 h compared with the group examined at 48 h. Carp maintained good quality during the selling conditions up to 24 h. This experiment deals with the effects of post-slaughter time and storage temperature on carp tissues. It is concluded that by considering the storage temperature (9-12 degrees C) and storage time (post-slaughter) the product maintained acceptable quality up to 24 h. There was significant deterioration of sensory quality, as a result of changes in chemical constituents.