Preparation, characterization, identification, and antioxidant properties of fermented acai (Euterpe oleracea)

Fermentation technology was used to prepare the acai (Euterpe oleracea) fermentation liquid. The optimal fermentation parameters included a strain ratio of Lactobacillus paracasei: Leuconostoc mesenteroides: Lactobacillus plantarum = 0.5:1:1.5, a fermentation time of 6 days, and a nitrogen source supplemental level of 2.5%. In optimal conditions, the ORAC value of the fermentation liquid reached the highest value of 273.28 +/- 6.55 mu mol/L Trolox, which was 55.85% higher than the raw liquid. In addition, the FRAP value of the acai, as well as its scavenging ability of DPPH, hydroxyl, and ABTS free radicals, increased after fermentation. Furthermore, after fermentation treatment, the microstructure, basic physicochemical composition, amino acid composition, gamma-aminobutyric acid, a variety of volatile components, and so on have changed. Therefore, fermentation treatment can significantly improve the nutritional value and flavor of the acai. This provides a theoretical basis for the comprehensive utilization of acai.