Abstract: Cocoon silk contains approximately 2 wt% of polyphenols, and the residue of these polyphenols is closely related to some factors, such as producing area, variety, season, processing methods and so on. Therefore, we can know the identity of raw silk products by detecting the polyphenols residue in the silk. Currently, there is no reliable and accurate method for determining the polyphenol content in cocoon silk. In this study, a quantitative method for detecting the content of polyphenols in cocoon and silk using the Folin phenol colorimetric method through Response Surface Methodology (RSM) was established. The effects of the dosage of Folin phenol reagent, the dosage of Na2CO3 solution, reaction time, and detection wavelength on the determination of polyphenol content in cocoon and silk were investigated. On the basis of single factor experiments, the detection conditions of cocoon and silk polyphenols were further optimized through Box Behnken design. It is shown that the detection wavelength, reaction time and amount of Na2CO3 solution have significant influence on the quantification results, while the amount of Folin phenol solution within the range of 1.0 mL to 1.4 mL has insignificant influence on the result. According to the result of Box Behnken design trial, the optimal detection conditions for cocoon and silk polyphenols are: 1.1 mL of Folin phenol solution, 0.65 mL of Na2CO3 solution, 32 minutes of reaction time, and detection wavelength of 760 nm. This method has good repeatability and reproducibility, and high detection stability within 40 minutes. The proposed method is accurate, reliable and low-cost, and can be applied for the detection of the content of polyphenols in silk cocoons, raw silks and related silk products.

Key words:  , cocoon and silk, content of polyphenols, quantity, Folin-Ciocalteu method, Response Surface Methodology (RSM)

摘要： 茧丝中的多酚含量是进行茧丝身份溯源的重要依据。以茧丝多酚含量的定量测定为研究对象，通过响应面优化法建立了由Folin酚比色法定量检测茧丝多酚含量的方法，同时考察了Folin酚试剂的用量、Na2CO3溶液的用量、反应时间及检测波长对茧丝多酚含量测定的影响。在单因素试验的基础上，通过Box-Behnken设计优化茧丝多酚的检测条件。结果表明：茧丝多酚的最适检测条件为1.1 mL的Folin酚溶液用量、0.65 mL的Na2CO3溶液用量、32 min的反应时长和760 nm的检测波长。文章建立的方法具有较好的重复性和重现性，且稳定性高，准确可靠，成本低廉，可用于桑蚕茧和生丝产品中多酚含量的检测。

关键词: 茧丝, 多酚, 单因素, Folin酚法, 响应面优化法