تاثیر اسانس زیره سیاه و آویشن بر ویژگیهاي کیفی و ماندگاري ماهی منجمد و تازه

Plant essential oils and extracts are the compounds that can inhibit bacterial growth at low concentrations. Also, these materials are mostly strong antioxidants and the presence of these two properties together increases the shelf-life of fish. This study was done to investigate effect of various concentrations of caraway and thyme essences on chemical and microbial quality of common carp fillet. Different concentrations of essential oils (0, 500, 1000 and 2000 mg/l) were added to fish samples and some chemical and oxidation factors, microbial quality and sensory properties of the samples were determined. The results showed the lowest levels of total volatile basic nitrogen was related to 2000 mg/l thyme essential oil (24.6 mg/100 g fillet) and the highest amount of total volatile basic nitrogen were observed in control treatment (75.11 mg/ 100g fillet) at refrigerator temperature. TBA levels in all treatments increased with increasing storage time and at the end of the storage period, except in 500 and 1000 mg/l thyme essences treatments, there was significant difference among all experimental samples (p<0.05). The results showed that various concentrations of essences reduced the total count and Psychrotrophic bacteria compared to the control. At the end of the storage time, treatment of 2000 mg/l caraway essence, 1000 mg/l caraway essence and 2000 mg/l thyme essence had the lower Psychrotrophic bacteria than the other samples. Treatments with 1000 and 2000 mg/l caraway essences in freezing conditions received the most colors score. The highest score of texture was related to 2000 mg/l thyme essential oil at refrigerator temperature. Samples containing 1000 mg/l caraway essence in freezing temperatures had the highest odor score. In general, 1000 and 2000 mg/l concentrations of thyme essence due to acceptance of the organoleptic characteristics from the consumer view as well as reduce microbial growth and chemical factors are recommended. [ABSTRACT FROM AUTHOR]