فهرست مطالب zohre didar

Oxidation of lipids in food is one of the most important factors in food degradation during processing, storage and distribution through adverse effects on aroma, color, nutritional value and also the production of toxic compounds. In this regard, this study was conducted to investigate the antioxidant effects of free grape pomace extract and nanoliposomes containing it on some oxidation parameters of soybean oil. In this study, 5 concentrations of nanoliposomes containing grape pomace extract (50, 100, 200, 500 and 1000 ppm), one level (200 ppm) of synthetic antioxidant (BHT) and one concentration (500 ppm) of free grape pomace extract were used and tests such as Acidity, peroxide, thiobarbituric acid index, conjugate diene, oxidative stability and refractive index of oils were stored in a laboratory oven at 63 ° C for 7 days. The results showed that with increasing the concentration of nanoliposomes containing antioxidants of grape pomace extract up to 500 ppm, the increase in acidity, thiobarbituric acid index, peroxide, conjugated diene and refractive index was less intense, but at higher concentrations of nanoliposomes used in this oil, Increased more. On the other hand, it was found that with increasing storage time, the amount of acidity, thiobarbituric acid, conjugated diene increased, but the amount of peroxide and refractive index of oils increased until the fifth day and then decreased. The results also showed that the highest oxidative stability of oils (7.6 h) was related to the sample containing 500 ppm nanoliposomes containing antioxidant extract of grape pomace. Finally, it can be said that the use of nanoliposomes containing grape pomace antioxidant extract is a good alternative to synthetic antioxidants on the market.

In this study, first extraction from the C. dactylon rhizomes was performed with methanol solvent using maceration method, and total phenolic compounds in the extract were identified and determined. Then the antioxidant effects of the extract in different concentrations (0, 100, 200, 400, 800 and 1000 ppm) on the oxidative stability factors of soybean oil including peroxide value, acidity value, thiobarbituric acid index (TBA) and rancimat value during kept of oil in an oven at 60 °C for 72 hours was evaluated and compared with the synthetic antioxidant BHT (200 ppm). The identification results of phenolic compounds by GC/MS showed that the total amount of phenolic compounds in the C. dactylon rhizomes extract was measured as 917.08 mg/kg and the major phenolic compounds of the extract including Hydroquinone (66.89%), Thymol (1.23%), Levoglucosenone (2.48%) and Vanillic acid (1.35%) were identified. With increasing the concentration of the extract, the amount of polyphenolic compounds and as a result, the free radical scavenging activity of the extract increased. Evaluation of soybean oil stability against oxidation also showed that among the studied concentrations of methanolic extract, the concentration of 1000 ppm due to having the highest amount of phenolic compounds and therefore the highest antioxidant activity, was determined as the most effective concentration level of the extract in increasing the oxidative stability of soybean oil, so that better results were obtained than BHT synthetic antioxidant at a concentration of 200 ppm. Thus, the methanolic extract of the C. dactylon rhizomes can be used as a cheap and available antioxidant source in the edible oils industry.

One of the problems with the consumption of fresh vegetables is the possibility of contamination with pathogenic bacteria. Washing fresh vegetables plays an important role in reducing the microbial population and increasing the safety of these products. Electrolyzed water has been considered as a new disinfectant in recent years. It is antiseptic, inexpensive and safe that affects different species of bacteria, fungi and viruses. In this study, the use of various types of washing water has been studied on the reduction of Shigella Flexneri population in lettuce. Types of water used include drinking water, acidified drinking water, chlorinated deionized water with chlorine concentrations of 50 and 25 mg / L, neutralized electrolyzed water, acidified electrolyzed water with a chlorine concentration of 50 and 25 mg / L were studied at different washing times (60 and 180 seconds) and different washing temperatures (4 and 25 °C). The results of this study showed that electrolysis of water had the most efficiency in reducing the microbial load of lettuce (72%) and the acidification of electrolyzed water increased its disinfection efficiency (75%). In addition, the study of lettuce microbial population during 1 to 4 days showed that the growth rate of microbial growth in lettuce samples was slower than other washing methods.