Artificial diets are increasingly utilized in sericulture, yet they often yield cocoons with properties that differ from those produced by mulberry leaf-fed silkworms. A reliable method to distinguish between these two types of cocoons remains lacking, compromising quality control in silk-related industries. In this study, we report a multidimensional analysis method integrating chemical, structural, and biomarker analyses to distinguish cocoons produced by mulberry leaf-fed (Mul-fed) silkworms from those produced by artificial diet-fed (Art-fed) silkworms. The SEM images showed that after the process of biomarker extraction, Mul-fed cocoons had a more complete morphological structure than Art-fed cocoons, and the sericin layer of Mul-fed cocoons was less damaged. Thermogravimetric and amino acid analyses revealed no significant differences between the two types of cocoons. Biomarker analyses via ultra-performance liquid chromatography–mass spectrometry (UPLC-MS) revealed that quercitrin and quercetin were enriched in Mul-fed cocoons, while daidzein and genistein were enriched in cocoons produced by artificial diet-fed silkworms. Furthermore, materials extracted from Mul-fed cocoons demonstrated significantly superior bioactivity than those from Art-fed cocoons in in vitro assays. This study provides a reliable and accurate method for assessing cocoon quality and distinguishing cocoons from different feeding methods, laying a robust basis for quality evaluation and silk product development.
Meng et al. (Tue,) studied this question.