اثر فرایند سرخ کردن بر ویژگی‌های اکسیداتیو و حرارتی فرمولاسیون بهینه روغن کنجد و هسته انگور

استفاده از روغن هسته انگور در رژیم غذایی با توجه به غنی بودن آن از اسیدهای چرب ضروری و ترکیبات آنتی‌آکسیدانی همچون توکوفرول‌ها و پلی‌فنول‌ها می‌تواند نقش موثری در سلامتی مصرف‌کننده داشته باشد. با این حال پایداری اکسیداتیو این روغن نسبتاً پایین بوده و مخلوط کردن آن با روغن‌های پایدارتر از جمله روغن کنجد می‌تواند روشی مناسب جهت بهبود پایداری اکسیداتیو آن باشد. طی حرارت دهی تغییرات فیزیکی و شیمیایی مختلفی در روغن رخ می‌دهد که بر کیفیت روغن تاثیر گذار است. در این پژوهش، پایداری حرارتی مخلوط روغن کنجد (75 %) و روغن هسته انگور (25 %) طی 90 دقیقه فرآیند سرخ‌ کردن در دمای c°180 مورد بررسی قرار گرفت. طی فرآیند سرخ‌کردن، در فواصل زمانی 30 دقیقه شاخص‌های اصلی کیفی روغن شامل عدد اسیدی، مقدار پراکسید، اندیس پارا آنیسیدین، ترکیبات فنولی و درصد ترکیبات قطبی مورد سنجش قرار گرفتند. نتایج آزمون‌های اختصاصی روغن‌های سرخ‌کردنی نشان داد که با افزایش زمان فرآیند سرخ‌کردن، میزان عدد اسیدی، اندیس پارا آنیسیدین و درصد ترکیبات قطبی افزایش پیدا کردند ولی مقدار پراکسید تنها تا 60 دقیقه اول فرآیند افزایش یافت و پس از آن کاهش یافت. با افزایش زمان حرارت دهی مقدار ترکیبات فنولی کاهش یافت. مقایسه مقادیر بدست‌آمده برای فاکتورهای مختلف مخلوط روغن‌های کنجد و هسته انگور با حدود مجاز استاندارد ملی ایران نشان داد که پارامترهای عدد اسیدی و پرکسید بیش از حدود مجاز استاندارد ملی ایران بود، ولی مقدار ترکیبات قطبی در محدوده مجاز استاندارد ملی ایران قرار داشت. مخلوط روغن‌های کنجد و هسته انگور برای حرارت‌دهی طولانی مدت و سرخ کردن مناسب نمی‌باشد.

Effect of frying process on the oxidative and thermal properties of sesame and grape seed oil optimized formulation

Using grape seed oil in the diet due to its richness of essential fatty acids and antioxidant compounds such as tocopherols and polyphenols can play an important role in the health of consumers. However, the oxidative stability of this oil is relatively low and mixing it with more stable oils such as sesame oil can be a good way to improve its oxidative stability. When the oil heated, various physical and chemical changes occur that affects the quality of the oil. In this research, the thermal stability of the mixture of sesame oil (75%) and grape seed oil (25%) was investigated for 90 minutes of frying process at 180°C. During the frying process, at 30 minutes intervals, the main oil qualitative indicators including acid number, peroxide value, panisidine value, phenolic compounds, and polar components were measured. The results of specific tests of frying oils showed that, with increasing frying time, the acid number, panisidine value, and polar components were increased but peroxide value increased only for the first 60 minutes of the process and then decreased. Comparison of the obtained values for different factors of sesame and grape seed oil with the national Iranian standard limits showed that the parameters of acid number and peroxide value were more than the national standard of Iran, but the content of polar compounds was within the permissible national standard of Iran. Sesame and grape seed oil is not suitable for long term heating and frying. Using grape seed oil in the diet due to its richness of essential fatty acids and antioxidant compounds such as tocopherols and polyphenols can play an important role in the health of consumers. However, the oxidative stability of this oil is relatively low and mixing it with more stable oils such as sesame oil can be a good way to improve its oxidative stability. When the oil heated, various physical and chemical changes occur that affects the quality of the oil. In this research, the thermal stability of the mixture of sesame oil (75% w/w) and grape seed oil (25% w/w) was investigated for 90 minutes of frying process at 180°C. During the frying process, at 30 minutes intervals, the main oil qualitative indicators including acid number, peroxide value, panisidine value, phenolic compounds, and polar components were measured. The results of specific tests of frying oils showed that, with increasing frying time, the acid number, panisidine value, and polar components were increased but peroxide value increased only for the first 60 minutes of the process and then decreased. Comparison of the obtained values for different factors of sesame and grape seed oil with the national Iranian standard limits showed that the parameters of acid number and peroxide value were more than the national standard of Iran, but the content of polar compounds was within the permissible national standard of Iran. As final result, combination of 75% sesame and 25% grape seed oil is not suitable for long term heating and frying. Using grape seed oil in the diet due to its richness of essential fatty acids and antioxidant compounds such as tocopherols and polyphenols can play an important role in the health of consumers. However, the oxidative stability of this oil is relatively low and mixing it with more stable oils such as sesame oil can be a good way to improve its oxidative stability. When the oil heated, various physical and chemical changes occur that affects the quality of the oil. In this research, the thermal stability of the mixture of sesame oil (75% w/w) and grape seed oil (25% w/w) was investigated for 90 minutes of frying process at 180°C. During the frying process, at 30 minutes intervals, the main oil qualitative indicators including acid number, peroxide value, panisidine value, phenolic compounds, and polar components were measured. The results of specific tests of frying oils showed that, with increasing frying time, the acid number, panisidine value, and polar components were increased but peroxide value increased only for the first 60 minutes of the process and then decreased. Comparison of the obtained values for different factors of sesame and grape seed oil with the national Iranian standard limits showed that the parameters of acid number and peroxide value were more than the national standard of Iran, but the content of polar compounds was within the permissible national standard of Iran. As final result, combination of 75% sesame and 25% grape seed oil is not suitable for long term heating and frying.