Effects of Temperature and Time on Polyphenolic Content and Antioxidant Activity in the Pressurized Hot Water Extraction of Deodorized Thyme (Thymus vulgaris)
详细信息 查看全文
- 作者：Jos茅 R. Vergara-Salinas ; Jara P茅rez-Jim茅nez ; Josep Llu铆s Torres ; Eduardo Agosin ; Jos茅 R. P茅rez-Correa
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：November 7, 2012
- 年：2012
- 卷：60
- 期：44
- 页码：10920-10929
- 全文大小：327K
- 年卷期：v.60,no.44(November 7, 2012)
- ISSN：1520-5118
文摘
The effects of temperature (50鈥?00 掳C) and contact time (5鈥?0 min) on the pressurized hot water extraction of deodorized thyme were explored for antioxidant activity, polyphenol profiles, and total antioxidants. Six not previously reported polyphenolic compounds were identified in thyme. An inverse correlation was found between the antioxidant activity and total antioxidants with the amount and diversity of polyphenols. The highest total extract yield and antioxidant activity were obtained at 200 掳C, although maximum polyphenol extraction yields of hydroxycinnamic acids, flavones, flavonols/flavanones, and total polyphenols were detected at 100 掳C and 5 min. Higher temperatures and longer exposure times reduced extract polyphenol diversity. Dihydroxyphenyllactic acid was the only phenolic compound for which extraction yield increased with temperature, probably as a product of the thermal degradation of rosmarinic acid. Consequently, for extracting phenolics from thyme, 100 掳C and 5 min would be appropriate operating conditions, whereas antioxidant-active nonphenolic compounds were favored at higher temperatures and exposure times.