Enhancement of health-promoting compounds of pineapple (Ananas comosus L.) by impregnation with LAB-fermented beetroot (Beta vulgaris L.) powder

Abstract This study aimed to develop pineapple wedges added with health-promoting compounds (antioxidants, prebiotics, and probiotics) and evaluate their stability during storage. Fresh pineapple wedges were first predried (6 h at 60 °C), impregnated (1 min at 20 °C) with fermented solutions ( Lactobacillus acidophilus ) formulated with whey, inulin, and/or beetroot powder, and then thoroughly dried (40 °C for 1 h) to be stored at 20 ± 2°C for 30 days. The physicochemical, total betalains (TB), total phenolic compounds (TPC), antioxidant capacity (AC), probiotic survival, and sensory acceptance of pineapple were evaluated at the beginning and end of the storage. Overall, storage time did not affect the physicochemical characteristics of pineapples (except titratable acidity). On the other hand, TB were incorporated into pineapples impregnated with fermented solutions containing beetroot, showing values of 31.69 to 31.86 mg/100 g. Adding inulin significantly enhanced the TPC in pineapples (12.7–26.2%, p < 0.05) compared with control pineapple. Therefore, pineapples with beetroot powder and inulin showed the highest AC (30.87–31.69 mg Trolox/g) after storage. By contrast, the probiotic survival remained up to 10 6 colony-forming units (CFU)/g for 15 days of storage. However, after 30 days, the microbial load decreased to < 10 2 CFU/g. Sensory evaluation indicated that dried pineapples were not affected by the storage time and impregnation systems displaying values of 5–6 (I like it - I like it moderately). In conclusion, pineapple wedges impregnated with fermented solution based on whey, inulin, and beetroot showed the highest AC and an appropriate probiotic count to exert its beneficial effects for 15 days.