Optimization of Roasting Conditions on the Bioactive Compounds and their Antioxidant Power from Opuntia fiscus-Indica Seeds using Response Surface Methodology (RSM)

Abstract

This work is aimed to optimize the effects of different roasting factors on the bioactive compound’s antioxidant capabilities of opuntia ficus indica seeds by using DPPH and ABTS assays. The Box-Behnken design (BBD) was applied to optimize the roasting temperature (X1:60-200 °C), roasting time (X2:10-50 min), and extraction time (X3: 3–6h). The optimal conditions of roasting applied in order to optimize the greatest content of the responses were: TPC (Total Phenolic Content): X1:200 °C, X2: 50 min, and X3: 5.49 h with 103.5±0.76 GAE/g extract experimental response, TFC (Total Flavonoids content): X1:200°C, X2:50min, and X3:3.16 h with 104.29±0.54 mg QE/g extract experimental response, TTC (Total Condensed Tannins Content ): X1: 200°C, X2: 50min, X3: 6h with 10,16±0.89 mg QAE/g extract experimental response, TSC ( Total Sugars Content ): X1: 60°C, X2:50 min, X3:5.12 h with 40.35±0.99 mg D-Glu E/g extract an experimental response. The maximal antioxidant power by DPPH and ABTS assays was recorded at a strong temperature of roasting. Moreover, the significant correlations were obtained by the principal component analysis (PCA), the first step, between the bioactive compounds, and on the second step, between their antioxidant capacities (DPPH, ABTS). Hierarchical Cluster Analysis (HCA) classified extracts into three clusters on the basis of measured antioxidant activity characteristics. Therefore, the result of this work indicates that roasted Opuntia ficus Indica seeds could be used as a significant human nutrient.