جستجوی مقالات مرتبط با کلیدواژه « رنسیمت » در نشریات گروه « پزشکی »

Fats and oils play important sensory and functional roles in food products. They are responsible for enhancing and releasing flavor components that react with other components to enhance the texture and mouthfeel of fried foods. Fat is a natural factor in making the food delicious. When frying food, hot oil penetrates into it, replaces its water content and makes it significantly more pleasant. This absorbed fat makes the crust crispy and affects the taste. In this study, the effect of deep frying process in sesame, canola and frying oils on nutrients and bioactive compounds of onions and potatoes and evaluation of their antioxidant activity were investigated.

Slices of potato and onion were fried in sesame oil, canola and special frying oils for 8 minutes and 4 minutes, respectively. Deep frying was carried out in three separate steps (for new samples but in that oils) with an interval of three hours between each step. Slices of fried potatoes and onions were evaluated by measuring total polyphenol factors, fatty acid composition and antioxidant activity.

During frying, elaidic acid is produced in canola oil (1.14-1.53% in the first and third stages of frying, respectively), but no significant difference was observed between the first stage and the third one. Due to the oxidation of linoleic acid in all fried onion and potato samples the content of linoleic acid decreased palmitic acid content was increased. The height amount of total poly phenols in fried potato slices were found in potatoes fried in sesame oil followed by potatoes fried in canola and finally in frying oils. The same observations were made for onion slices fried.The amount of polyphenols in fried samples showed a significant difference as compared to pre-frying (P <0.05). The highest oxidation resistance as indicated by Rancimat test was observed in potato slices fried with sesame oil, followed by special frying and finally canola oils. The same observation was made for onion slices.

It might be concluded that sesame oil probably due to its fatty acid composition and oxidational contents might be regarded as a better media for deep frying applications as completion to canola and frying oils.

Rancimat is an automated technique to rapidly determine oxidative stability of fats and oils, which can also provide relatively good results regarding shelf-life prediction of the lipid system. In this research, the oxidative stability of different types of pistachio oil (wild and domesticated species) by using rancimat and the influences of chemical properties of pistachio oil on oxidative stability were determined.
The present study is a laboratory study. Oils of five pistachio varieties (including Bane, Ahmadaghaie, Kalleghouchi, Akbari, and Fandoghi) were extracted by solvent. The fatty acid profile of the pistachio oil was determined by gas chromatography, and chemical methods were used to measure the amount of antioxidants and oil quality indicators. Oxidative stability was determined by Rancimat. The mean values were compared using MStatC 2.10 software and based on the Duncan’s test at the level of 5%.
Oleic Acid and Palmitic Acid were the most representatives of total fatty acid and saturated fatty acids (SFAs) in pistachio oil, respectively. The highest percentage of oleic acid was observed in Ahmadaghaie variety and the highest and lowest percentage of mono unsaturated fatty acids (MUFA) and poly unsaturated fatty acids (PUFA) were observed in Bane Hull Oil (65%, 7.9%) and the lowest and highest percentage of MUFA and PUFA were observed in Bane Kernel Oil (53%, 32.8%). The highest Oxidative Stability Index was found in Bane Hull Oil (BHO), Bane Kernel Oil (BKO) and Ahmadaghaie oil, respectively. Activation energy was evaluated in the range of 92 to 98.2 kj/mol. The results showed that shelf-life of BHO, BKO and Ahmadaghaieoil were 786, 386 and 280 days at 25 ⁰C, respectively. Ahmadaghaie shelf-life was over 1.5 times more than those of the other commercial varieties.
Fatty acid composition and amount of antioxidants were the most important factors on oxidative stability of the pistachio oil and the cause of higher shelf-life of oil of wild pistachio types rather than the other commercial varieties. Among the domesticated species of pistachio, Ahmadaghaie variety is suitable for oil extraction and high thermal processes such as roasting.

The consumers demand foods with high nutritional value that are free from chemical preservatives.This has led to numerous efforts to find natural antioxidants from herbal resources. Savory essence is a colorless to pale yellow liquid that contains phenolic compounds such as carvacrol, P-cymen and thymol that exhibit anti-oxidative and antimicrobial activities. The aim of this study is to quantify the phenolic compounds present in the essential oil of Satureja hortensis as a source of natural antioxidant and to examine its stabilising effect on colza and anchovy oils. The aerial parts of plant was collected, dried and the essential oils was extracted and analysed by GC/MS. Total content of phenolic compounds of the essential oils was determined by Folin-Ciocalteu method. The extracted essential oil was added to canola and anchovy oils at the concentrations of 0.05, 0.1, 0.2 and 0.3% and the antioxidant activities were measured and compared to the control and sample containing BHA. Peroxide value and tiobarbitoric acid value and induction period measurements by Rancimate were used as means to evaluate the antioxidant activities. Carvacrol, gamma-terpinene, alpha-terpinene and p-cymene were determined as the predominant compounds in the extracted essential oil. The total concentration of the phenolic compounds in the extracted oil was 0.739±0.27 mg/ml as Gallic Acid Equivalent. The added essential oil at the concentration of 0.3% exhibited the highest antioxidant activity in canola and anchovy oils. This study has indicated that the application of the natural essential oilsto suitable substances such as canola or anchovy oils in order to improve the stability of the oils and also to replace the synthetic antioxidants is desirable and preferred.