Physicochemical properties and antioxidant activity of Maillard reaction products derived from Dioscorea opposita polysaccharides

Dioscorea opposita Thunb., an edible and pharmaceutical plant, is usually consumed after heating processing, such as steaming, boiling, and frying with bran. In order to determine the effect of heating temperature on Maillard reaction products (MRPs) of polysaccharides from Dioscorea opposita (DOP), DOP-MRPs at 90–120 °C were prepared. The characterisation including colour, pH, FT-IR, XRD, fluorescence, UV–vis spectroscopy, and volatile compounds by GC-MS and GC-IMS were investigated. Results showed that the major volatile compounds of DOP-MRPs were acids, esters and ketones. Esters were generated the most (approximately 65.80%) at 90 °C, and acetic acids were produced approximately 25.70%. According to principal component analysis, flavours in DOP-MRP-90 and DOP-MRP-120 showed significant differences. Additionally, antioxidant activities including hydroxyl radical (HRS), DPPH scavenging and ferric ion reducing antioxidant power (FRAP) were conducted. The DOP-MRP-90 presented highest antioxidant activities, indicating that it donated more hydrogen atom to stabilize free radicals. This study provides a scientific basis for the application of the Maillard reaction in foods for Chinese yam polysaccharides. •Maillard reaction products from D. opposita polysaccharides (DOP-MRPs) were prepared.•113 volatile compounds of DOP-MRPs were determined by GC-MS and GC-IMS.•DOP-MRP-90 generated the largest amount of esters (65.80%), mainly triacetin.•9 types acids ranged in 25.70%–40.17% were found in DOP-MRPs, mainly acetic acid.•Polysaccharides heated at 90 °C presented better the antioxidant activity.