Quality of fermented pumpkin beverages under different fermentation conditions by <i>Lactobacillus plantarum</i> FNCC 020

Abstract Development of health-promoting natural products has received importance, and fermented pumpkin can be a viable option, mainly regarding its carotenoid contents. This study aimed to investigate the quality of fermented pumpkin beverages (FPB) under various fermentation conditions (control, T1 = 30 °C, 12 h; T2 = 30 °C, 18 h; T3 = 30 °C, 24 h; T4 = 40 °C, 12 h; T5 = 40 °C, 18 h; T6 = 40 °C, 24 h) by Lactobacillus plantarum. Cell count of lactic acid bacteria, pH, chemical quality (soluble solid, acidity, total sugar, total phenolic content, total flavonoid content, and antioxidant activity), carotenoid contents, and colour attributes (h*, chroma, L*, and yellowing index) of FPB samples were studied. As a result, LAB fermentation significantly affected acidity and total sugar of FPB samples, while it did not change pH and soluble solids significantly. Besides, carotenoid contents and colour attributes of FPB were not different during fermentation, indicating that L. plantarum fermentation retained carotenoids and maintained physical appearances. Regarding sugars and organic acids, their quantity changed due to fermentation and lactic acids increased greatly up to three times higher than control after 24 h of fermentation at 30 °C. Moreover, fermentation by L. plantarum improved total phenolic content, total flavonoid content, and antioxidant activity, and these may recommend FPB as a potential functional product.