Novel solid-state fermentation extraction of 5-O-caffeoylquinic acid from heilong48 soybean using Lactobacillus helviticus: Parametric screening and optimization

This study investigated the extraction of 5-O-caffeoylquinic acid (5-CQA) with increased yield and enhanced antioxidant activity from heilong48 soybean (HS) under solid-state fermentation (SSF). Plackett–Burman design and Box-Behnken design were sequentially used for screening and optimization of significant SSF conditions respectively. Screening results showed that temperature, pH, incubation time and liquid-solid ratio were the significant SSF conditions that influenced 5-CQA yield, fermentation efficiency and antioxidant activity. The optimum SSF conditions obtained by Box-Behnken design were 49.90 °C (temperature), 7.00 (pH), 25.81 h (incubation time) and 0.67 (liquid-solid ratio). For these conditions, the experimental data obtained [5-CQA yield (11.41 ± 0.27 mg/g), fermentation efficiency (30.49 ± 1.14%), and antioxidant activity (46.13 ± 1.94 μmol AA eq/g dry sample)] were consistent with predicted values, higher than that of unfermented HS flour (RSHF), and supported by Atomic force microscopy (AFM), Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM) microstructure. The results demonstrated that optimized SSF conditions significantly influenced 5-CQA yield, fermentation efficiency and antioxidant activity. This study showed that the use of optimized SSF conditions to extract 5-CQA with increased yield and enhanced antioxidant activity was efficient. Hence, this could be useful to the food and/or pharmaceutical industry in producing 5-CQA from HS. [Display omitted] •High 5-CQA yield and antioxidant activity were obtained in LHFHS than RHSF.•Temp, pH, IT and L-S ratio significantly influenced 5-CQA extraction from HS.•Acceptable, adequate and precise model was obtained.•AFM, FTIR and SEM results confirmed the structural changes in LHFHS.