Volume 11, Issue 45 (3-2014)
Abstract
Walnut green husk is waste of walnut that can be valuable source of natural compounds with antioxidant properties. In this study, the effect of regions (Shahrood, Bandar Gaz and Hzargarib),solvent (ethanol 96%, Water and ethanol - water (1:1 v/v)) and extraction time (6 to 24 hours) on the yield of extracted phenolic compounds from walnut green husk has been analyzed. Immersion method at room temperature in a factorial experiment with three replications in a completely randomized design has been used. Then, bioactive properties of walnut green husk extract in a completely randomized design have been compared. The total phenol content of the extract was determined by the method of Folin- ciocalteau. Antioxidant activity of the extract by the reducing power of Iron III and DPPH free radical scavenging ability was evaluated. The results of this study showed that, the solvent polarity, time extraction and plant habitat are effective on amount of extracted phenolic compounds; and also antioxidant activity of the extract depends on the concentration of phenolic compounds. The highest phenolic compounds with 49.66 mg/g (based on Galic acid) were achieved from Hezar jerib walnut green husks with water - ethanol solvent (1:1 v/v) for 24 hours. Also, the most antioxidant properties of the extracts were shown in this extract.
Volume 13, Issue 55 (9-2015)
Abstract
In this research, physicochemical properties and oxidative stability of Roghani virgin olive oil grown in two regions of Roodbar and Kazeroon, located in north and south of Iran respectively, with differences in pedoclimatic conditions, altitude and soil were investigated. To determine the physicochemical properties, acidity, peroxide value, spectrophotometric indexes at 232 and 270 nm, smoke point, specific gravity and refractive index as well as the total contents of phenolic compounds, alpha tocopherol, chlorophyll, carotenoid, and fatty acid composition were evaluated. To evaluate the oxidative stability, the effect of heat treatment at 180 °C for 8 hours on indicators such as conjugated diene value, carbonyl value, polar compounds and oxidative stability index were tested. Results indicated the differences in the structural properties and oxidative stability of the oil obtained from two regions. As the oil from Roodbar region with lower altitude, lower average annual temperature, higher average annual rainfall, and specific geographical conditions, contain higher phenolic compounds, alpha tocopherol and oleic acid and also showed higher oxidative stability during heat treatment. But the oil of Kazeroon region with higher altitude, higher average annual temperature, and lower average annual rainfall, had higher linoleic and linolenic acids and exhibited lower oxidative stability during thermal treatment. Therefore the results of this study can be used as a description of physicochemical properties and oxidative stability of Roghani olive oil from two regions of Roodbar and Kazeroon.
