Mechanism of physicochemical quality formation in Polygonatum odoratum powder prepared by vacuum microwave drying combined with extrusion-cooking: a metabolomics-based analysis.

INTRODUCTION

Polygonatum odoratum (P. odoratum) is the dried rhizome of plant Polygonatum odoratum (Mill.) Druce, and it is a well-known medicinal and edible plant extensively utilized in Asia, but its commercial products, sliced or strip forms, limiting its wider applications. The powdered form of P. odoratum offers greater convenience for modern food applications. This study aims to develop efficient processing strategies for high-quality P. odoratum powder.

METHODS

This study used fresh P. odoratum as raw material to investigate the quality of powder produced by vacuum microwave drying combined with extrusion cooking (combined approach) and compared it with powders obtained by hot-air drying and vacuum microwave drying alone. Electronic sensory technology, including electronic eye (e-eye), electronic noses (e-nose), and electronic tongues (e-tongue), were utilized to evaluate physical properties, in vitro antioxidant activity assays were used to preliminarily evaluate functional activity, and chemical analytical methods were employed for analyzing the main active components. Meantime, the differences in saponins and flavonoids among different processed products were determined by broad-targeted metabolomics techniques. Finally, correlation analyses of physical properties, antioxidant activity, and chemical properties were performed to investigate the mechanism underlying the formation of product quality.

RESULTS

The results showed that the combined approach enhanced the physicochemical properties and in vitro antioxidant activity of P. odoratum powder, primarily by effecting its flavonoid metabolites. Specifically, a deeper yellow color was achieved through reduced Phloretin content and increased Eriodictyol chalcone content; sweetness was enhanced by higher Eriodictyol levels; and antioxidant activity was enhanced by increased Eriodictyol content and the emergence of Epigallocatechin gallate.

CONCLUSION

The P. odoratum powder prepared by vacuum microwave drying combined with extrusion cooking process in this study exhibited high quality, and the process showed good industrial feasibility.