Analysis of some factors affecting the phenolic compounds extracted from green husk of walnut (Juglans regia L.)

Walnut green husk contains phenolic compounds which reduce cardiovascular diseases, prevent the risk of many cancers and LDL oxidation. Also they have antimutagenic, antioxidant and antimicrobial properties. In this research, effects of different parameters including blanching, solvent concentration, harvest time, extraction time and method were examined on amount of extraction and phenolic compound of walnut green husk. Walnuts were picked at three times (June, July and August) and half of them were blanched. Phenolic compounds of this sample were extracted with different concentrations of methanol (100%, 80%, and 60%) and different extraction methods (maceration, soxhlet, ultrasound, and microwave). Results showed that blanching treatments significantly affected the total phenolics (p < 0.05), and the blanched samples obtained in June and were extracted with 60% methanol in microwave had the highest phenolics.