Optimization of solid-state fermentation to enhance total flavonoids in tangerine peel and evaluation of antioxidant activity dataset

This dataset comprises experimental data generated during the optimization of solid-state fermentation conditions for enhancing total flavonoids in tangerine peel using Bacillus subtilis ATCC 6633, along with the evaluation of antioxidant activity. The data were collected at the Biology and Food Department of Engineering, Bozhou University, China.1. Data generation and processing1.1 Fermentation processSubstrate: dried tangerine peel (sourced from Bozhou, China) was ground and sieved (100-mesh). Microbial fermentation: B. subtilis ATCC 6633 was cultured and inoculated (5%-25% v/w) under varying conditions (temperature: 25–37 °C; liquid-to-solid ratio: 0.5:1–1.5:1 mL/g; time: 12–60 h). Extraction: total flavonoids were extracted using ultrasonic-assisted ethanol extraction (50% ethanol, 200 W, 30 min) and quantified via UV-Vis spectrophotometry (510 nm, rutin standard curve).UHPLC Analysis: Four key flavonoids (hesperidin, hesperetin, nobiletin, tangeretin) were quantified using Shimadzu Nexera X2 UHPLC (negative ion mode, MRM detection).1.2 Antioxidant assaysDPPH and ABTS free radical scavenging: assessed at concentrations (0.05–0.8 mg/mL) using a microplate reader (517 nm for DPPH; 734 nm for ABTS). Results expressed as % scavenging activity.2. Dataset Structure2.1 Primary dataset (SSF_Optimization_Data.csv)The primary dataset (SSF_Optimization_Data.csv) contains 29 rows (experimental runs) and 6 columns (process parameters and responses). Column details: number, inoculation volume (%), liquid-to-solid ratio (mL/g), fermentation temperature (°C), fermentation time (h) and total flavonoids yield (%).2.2 Statistical analysis (BBD_ANOVA_Results.csv)Model significance: F=11.71, p<0.0001 (R²=0.9213). Significant linear effects: Inoculation (A), Liquid ratio (B), Temperature (C) (p<0.05). Significant interaction: AB (p=0.0273). Lack of fit p=0.5944 (non-significant).2.2 Flavonoids_quantification.csvTotal flavonoids content in fermented vs. unfermented tangerine peel (p < 0.05). UHPLC-derived concentrations (mg/L) of four flavonoids in fermented vs. unfermented tangerine peel (p < 0.05 for significance).HPLC_Chromatograms.tif: UHPLC profiles of flavonoid standards and samples.2.3 Antioxidant_activity.csvDPPH and ABTS free radical scavenging rates (%) at five concentrations (0.05–0.8 mg/mL).3. Quality control and metadataError Ranges: total flavonoids: ±5% (UV-Vis standard curve, R² = 0.9989). Antioxidant assays: inter-assay CV < 10%. Units: consistent metric units (mg/g for flavonoids; % for scavenging activity).4. Software and accessibilityAnalysis: Design Expert v13 (BBD optimization), OriginPro 2024 (graphs), SPSSAU (statistics).Data Formats: .csv, .xlsx (compatible with Excel); UHPLC data require Shimadzu LabSolutions or equivalent.