莲衣粉多酚提取工艺优化及体外抗氧化活性研究

为探究酸性乙醇溶液(乙酸+乙醇+水)提取莲衣粉(LSPW)多酚的最佳工艺,明确莲衣粉多酚提取物(PEL)作为天然食品抗氧化剂的应用潜力,本研究在单因素试验基础上,通过响应面分析法优化莲衣粉多酚的提取工艺,并对PEL进行体外抗氧化研究。结果表明,莲衣粉多酚的最佳提取工艺为乙醇浓度41%、液料比59 mL·g^-1、乙酸添加量1.56 mL·100mL^-1、提取温度70℃、提取时间20 min。在此条件下,莲衣粉多酚得率达9.65%。PEL的多酚含量达24.03%,且其具有较强的清除DPPH自由基(IC₅₀=0.032 mg·mL^-1)、还原Fe³⁺(eq=268.64 mg AAE·g^-1)的能力,抑制脂质氧化能力分别相当于叔丁基对苯二酚(TBHQ)、叔丁基羟基茴香醚(BHA)的37.12%、39.20%(硫氰酸铁法)与72.92%、67.60%(硫代巴比妥酸法)。本研究为莲衣粉多酚的开发利用及PEL作为潜在的天然食品抗氧化剂提供了理论基础。

Optimization of Polyphenols Extraction From Lotus Seed Peel Waste and Its in Vitro Antioxidant Activities

In order to optimize the extraction process of polyphenols from lotus seed peel waste (LSPW) by acidic ethanol solution (acetic acid + ethanol + water), and investigate the potential application of the polyphenols extract (PEL) as a natural antioxidant in food, a response surface methodology was used to optimize the extraction process of polyphenols from LSPW, and the antioxidant activities of PEL were also investigated in vitro. The results showed that the optimum extraction process was as follows: ethanol concentration 41%, liquid to solid ratio 59 mL·g^-1, acetic acid addition amount 1.56 mL·100mL^-1, extraction temperature 70℃, and extraction time 20 min. Under these conditions, the yield of polyphenols from LSPW was 9.65%, and polyphenols content in the extract was 24.03%. PEL had strong ability to scavenge DPPH free radical (IC₅₀=0.032 mg·mL^-1) and reduce Fe³⁺ (eq.=268.64 mg AAE·g^-1), and its capacity to inhibit lipid oxidation was equivalent to 37.12%, 39.20% (FTC method) and 72.92%, 67.60% (TBA method) of that of tert-butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA), respectively. This study could provide a theoretical basis for the development and utilization of polyphenols from LSPW as well as the potential natural antioxidant of PEL in foods.