Ultrasound-Assisted Extraction of Phenolic Compounds from Unripe Grape (Qora)

作者：Bagheri Hatef; Esmaiili Mohsen^*

来源：Erwerbs-Obstbau, 2017, 59(3): 221-226.

DOI：10.1007/s10341-016-0315-5

• Unripe grape (qora)
• Phenolic compounds
• Resveratrol
• Ultrasound-assisted extraction

Optimization of the extraction and analysis of phytochemicals can improve the production and quality of foods. The aim of this study is to evaluate ultrasound-assisted extraction of phenolic compounds from unripe grape (Vitis vinifera). At first stage, conventional thermal extraction was carried out in order to optimize the temperature (50, 70, 90 A degrees C) and duration (20, 40, and 60 min) of the process (control). Investigations showed that the optimum condition of temperature and duration is 70 A degrees C and 30 min, respectively. Then, grape pulp was treated for 30 min by ultrasound at a fixed frequency of 20 kHz. Results showed that ultrasound application increased the total phenolic content of the samples considerably. In addition, individual phenolic composition of the samples, namely rutin, gallic acid, hydroxybenzoic acid, syringic acid, p-coumaric acid, quercetin, and resveratrol were measured by HPLC. A good relation was observed between chromatographic and total phenol results. This study showed that ultrasound-assisted extraction is a sufficient method to produce verjuice as a rich and inexpensive source of antioxidants.

• 出版日期2017-9