اثر فرآيند خشك كردن حرارتي بر خواص كيفي و حسي ماهي قزل‌الاي رنگين كمان (Oncorhynchus mykiss)

Effect of heat drying on the biochemical compound, quality and sensory properties of rainbow trout (Oncorhynchus mykiss)

در اين پژوهش تغييرات تركيبات بيوشيميايي، كيفي و حسي ماهي قزل آلاي رنگين كمان تحت فرآيند خشك كردن حرارتي مورد بررسي قرار گرفت. بدين‌منظور ميزان رطوبت، پروتئين، چربي و خاكستر ماهي تازه و خشك شده و نگهداري شده تعيين گرديد، به منظور بررسي خصوصيات كيفي محصول از آزمون‌هاي اندازه‌گيري اسيد‌هاي چرب آزاد، pH و TBA استفاده گرديد ارزيابي حسي به روش هدونيك انجام شد. بر اساس نتايج طي خشك كردن ميزان پروتئين از 16/70 به 89/ 28درصد و چربي از 4/01 به 13/09 درصد افزايش يافت. خشك كردن باعث افزايش اسيد‌هاي چرب اشباع و تك غير اشباع (4 درصد) و كاهش مجموع اسيد‌هاي چرب غير اشباع (7/26 درصد) گرديد. خشك كردن حرارتي تاثير معني داري بر كاهش ميزان اسيد‌هاي چرب امگا 3 در ماهي قزل آلاي رنگين كمان داشت و ميزان آن را از 16/1 درصد به 7/37 درصد رساند. كيفيت ماهي طي خشك كردن به طور كلي كاهش يافت و طي نگهداري اين كاهش با شدت بيشتري مشاهده گرديد. ميزان TBA از 0/032 تا 1/065 متغير بود نتايج نشان داد طي نگهداري ميزان TVBN و pH به صورت معني‌داري افزايش يافت. ميزان اسيد‌هاي چرب ازاد گوشت تازه ماهي قزل آلاي رنگين كمان 0/36 درصد بوده است كه طي خشك كردن ونگهداري به ترتيب به 1/1 و 1/56 درصد رسيد. خصوصيات حسي ماهي نيز در اكثر فاكتورها بجز فاكتور حسي بو ماهي، طي خشك كردن كمي كاهش يافت و طي نگهداري در يخچال اين افت ادامه داشت.

In this study, the biochemical composition, and quality and sensory properties of rainbow trout were studied by thermal drying process. For this purpose, the amount of moisture, protein, fat, ash and dried fish were measured and stored, as well as to the impact of this process on the composition of fatty acids, fatty acid profile of fresh fish and dried were determined. To evaluate the quality of tests measuring volatile nitrogenous bases, free fatty acids, pH and TBA were used. sensory properties were carried out in five Hedonic methods. The results showed that the drying rate from 16.70 to 28.89 percent protein and fat from 4.10 to 13.09 percent as reducing the amount of water during the drying of fish. Drying increases the saturated fatty acids and mono-unsaturated (4%) and a decrease in unsaturated fatty acids, especially polyunsaturated (26.7 percent), respectively. Drying temperature had a significant effect on the level of omega-3 fatty acids found in fish rainbow trout and its rate from 1.16 percent to 7.37 percent increase. During the drying of fish generally decreased during storage, this reduction was observed with greater intensity. The TBA from 0.032 to 1.065 varied TVBN rate and pH during storage showed a significantly increased. Free fatty acid content of fresh meat rainbow trout 0.36 percent during drying maintenance and 1.56, respectively, to 1.1 percent. Sensory characteristics of fish, most fish smell sensory factors except factor, fell slightly during drying during storage at refrigerator continued to decline.