The present work describes the effect of modified atmosphere packaging (MAP) on quality characteristics and shelf life extension of the Kashar cheese using physicochemical, microbiological, color and sensory analyses. Three different modified atmosphere conditions were studied (20% carbon dioxide [CO₂]/80% nitrogen [N₂], 40% CO₂/60% N₂ and 100% CO₂). Control cheeses were packaged in air. In the cheeses, the predominant short-chain fatty acid was lauric acid, the most abundant medium-chain fatty acid was palmitic acid and long-chain fatty acid was oleic acid. Microbiological results showed that 100% CO₂ was the most effective treatment inhibiting the growth of mesophilic aerobic bacteria (Plate Count Agar) and yeasts–molds (Potato Dextrose Agar) until the end of storage period. Generally, sensory scores were significantly affected by both storage period and MAP treatment, but the gas composition with 40% and 100% CO₂ had similar impact on the cheese samples at the end of storage period. PRACTICAL APPLICATIONS In the recent years, the increase of consumer demands for fresh, preservative-free foods has obligated to use suitable packaging methods for all the various kinds of cheeses, due to possible undesirable modifications of product structure and appearance. One of the methods for protection is the use of modified atmosphere packaging. Carbon dioxide (CO₂) atmosphere guaranteed the best microbiological stabilization and sensorial properties of the fresh cheeses. This study determined that 40 and 100% CO₂ can be used to extend the shelf life of fresh Kashar cheese.

Effects of Microbial Transglutaminase on Physicochemical, Microbial and Sensorial Properties of Kefir Produced by Using Mixture Cow's and Soymilk kefir;transglutaminase;volatile aromatic compounds;syneresis; The objective of this research was to investigate the effects microbial transglutaminase (mTGs) on the physicochemical, microbial and sensory properties of kefir produced by using mix cow and soymilk. Kefir batches were prepared using 0, 0.5, 1 and 1.5 Units m-TGs for per g of milk protein. Adding m-TGs to milk caused an increase in the pH and viscosity and caused a decrease in titratable acidity and syneresis in the kefir samples. Total bacteria, lactobacilli and streptococci counts decreased, while yeast counts increased in all the samples during storage. Alcohols and acids compounds have increased in all the samples except in the control samples, while carbonyl compounds have decreased in all the samples during storage (1-30 d). The differences in the percentage of alcohols, carbonyl compounds and acids in total volatiles on the 1st and the 30th d of storage were observed at 8.47-23.52%, 6.94-25.46% and 59.64-63.69%, respectively. The consumer evaluation of the kefir samples showed that greater levels of acceptability were found for samples which had been added 1.5 U m-TGs for per g of milk protein.