Abstract:To investigate the effects of fermentation on the quality characteristics and biological activities of freeze-dried mulberry jam powder，a comparative study was conducted between fermented and non-fermented freeze-dried mulberry jam powder. Fermented jam was prepared using fresh mulberries as raw material，followed by enzymatic hydrolysis for cell wall disruption and inoculation with Lactobacillus plantarum. The sensory scores，nutritional quality，and antioxidant efficacy of both samples were systematically compared in this study. The results showed that，compared with the unfermented Freeze-Dried Mulberry Jam Powder，the fermented type exhibited total acid content of 1.47%，total sugar of485.15 mg/g，reducing sugar of292.52mg/g，anthocyanin content of 3 122.56 μg/g，lactic acid of 20.89 μmol/g，hydroxyl radical scavenging rate of 36.06%，superoxide anion production rate of 76.74 nmol/（g·min），and ferric reducing antioxidant power（FRAP） was 83.72 μmol Trolox/g，2，2'-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid）diammonium salt（ABTS） free radical scavenging capacity was 15.49 μmol Trolox/g，and 1，1-diphenyl-2-picrylhydrazyl（DPPH） free radical scavenging rate was 11.94 μmol Trolox/g respectively，they still maintained relatively high levels. Correlation analysis was performed to evaluate the relationships among various indicators. The results indicated high correlations among total acidity，reducing sugar，total phenolic content，anthocyanin，and FRAP antioxidant capacity. The combined process of'pectinase hydrolysis-Lactobacillus fermentation-vacuum freeze-drying' for preparing freeze-dried mulberry jam powder could preserve partial nutrients and active components of mulberries，maintain relatively high antioxidant activity，and produce Freeze-Dried Mulberry Jam Powder with excellent sensory quality，portability，and storage stability. This study provides a theoretical foundation for the deep processing of jams with low sugar and additives.