Folin-Ciocalteu比色法应用于蔬菜和水果总多酚含量测定的研究

STUDY ON THE DETERMINATION OF TOTAL POLYPHENOLS CONTENT IN VEGETABLES AND FRUITS BY FOLIN-CIOCALTEU COLORIMETRY

目的优化Folin-Ciocalteu比色法测定总多酚含量的条件,应用该法在最适反应条件下测定22种蔬菜和4种水果中的总多酚含量。方法以吸光度为评价指标,分别对样品中总多酚的浸提方法、测定波长、呈色反应体系中主要反应液的用量、显色温度、反应时间进行优化并逐一考察Folin-Ciocalteu比色法的重复性、精密度、稳定性和加标回收率后,以没食子酸为标准品,在最适反应条件下对22种蔬菜和4种水果中的总多酚含量进行测定。结果经过一系列优化试验,确定Folin-Ciocalteu比色法的最佳反应条件为:以50%丙酮溶液为总多酚提取溶剂,Folin-Ciocalteu显色剂用量2ml,10%碳酸钠溶液用量10ml,显色温度50℃,反应时间1h,测定波长765nm。没食子酸标准品在质量浓度0～0.20 mg/ml范围内与其吸光度呈良好线性关系(R2=0.9987),Folin-Ciocalteu比色法重复性试验RSD为3.89%,精密度试验RSD为1.89%,稳定性试验RSD为0.40%,平均回收率为102.12%,RSD为1.27%。22种蔬菜中豇豆总多酚含量最高(143.20mg/100g),西葫芦最低(10.54mg/100g),4种水果中苹果总多酚含量较高(83.77mg/100g)。结论 Folin-Ciocalteu比色法在本研究建立的最适条件下显色灵敏、准确可靠、稳定性高、简便易行,适用于对蔬菜和水果总多酚进行含量测定。

Objective To optimize the determining conditions of Folin-Ciocalteu colorimetry and apply them to determine the total polyphenols content in 22 kinds of vegetables and 4 kinds of fruits.Method Absorbency was adopted as evaluation index,and the extracting method of polyphenols,detecting wavelength,dosage of main reagents,reacting temperature and duration were optimized respectively.After repeatability,precision,stability and retrieving rate of Folin-Ciocalteu colorimetry were evaluated,it was used to determine total polyphenols content in vegetable and fruit specimens in optimal conditions,with gallic acid as reference.Results The optimal conditions of Folin-Ciocalteu（FC） colorimetry were established as follow：polyphenols extracted with 50% acetone,FC reagent 2 ml and 10% Na2CO3 10 ml,reacting temperature 50℃,reaction time 1h,and detecting wavelength 765nm.As for Folin-Ciocalteu colormietry,concentration of gallic acid and its absorbency bear good linearity in the range of 0～0.20 mg/ml（R2=0.9987）.The relative standard deviation of its repeatability test,precision test and stability test were 3.89%、1.89% and 0.40% respectively.Its average retrieving rate was 102.12%（RSD 1.27%）.Among all the vegetables determined,cowpea contained the most polyphenols（143.20mg/100g）,cucurbita pepo the least（10.54mg/100g）.Apple exhibited relatively high polyphenols content among all fruits.Conclusion Folin-Ciocalteu colorimetry established in this study is simple,fast,highly sensitive and very stable.It is suitable to be applied to determine total polyphenols content in vegetables and fruits.