Use of response surface methodology to study the combined effects of UV-C and thermal processing on vegetable oxidative enzymes

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• 作者：Fern ; o Sampedro ; John Phillips ; Xuetong Fan
• 关键词：UV-C ; Peroxidase ; Polyphenoloxidase ; Lipoxygenase ; Central composite design
• 刊名：Lebensmittel-Wissenschaft und -Technologie
• 出版年：January, 2014
• 年：2014
• 卷：55
• 期：1
• 页码：189-196
• 全文大小：830 K

文摘

The combined thermal (25-65聽掳C) and ultraviolet processing (UV-C) effects on lipoxygenase (LOX), peroxidase (POD) and polyphenoloxidase (PPO) at different pH values (4.0-7.0) were studied using a central composite design. An initial screening design revealed that all factors had a significant effect on enzymatic activity except wavelength which showed a negligible effect. A synergistic effect was found between temperature and UV exposure time for POD and PPO and between pH and exposure time for LOX. LOX enzyme was affected by acidic conditions. POD was UV-C labile whereas PPO was the most UV-C resistant enzyme but was thermolabile. Second-order polynomial equations indicated that enzyme activities were inactivated after exposure to 58.2聽mJ/cm² UV at 60聽掳C or higher temperatures at any pH condition. Combination of UV and thermal processing allowed the use of low energy/doses to obtain complete enzymatic inactivation. This study may serve as a basis to design UV-C processes for the inactivation of enzymes in liquid matrices.