Optimization of bioactive compound mixtures: Polyphenol content, antioxidant activity, and synergistic effect

The rapid expansion of the food industry has significantly increased the generation of by-products rich in bioactive compounds with untapped potential. This study aims to optimise the mixtures of bioactive compound by evaluation of the polyphenol content, antioxidant and synergistic effects. The Simplex-Centroid design and response surface methodology (RSM) combined with correlation analysis were used for this purpose. Each of the three investigated bioactive substances Sodium L-ascorbate (SLA); Dihydroquercetin isolate from Larix sibirica Ledeb (DHQ), and freeze-dried (30% w/v) ethanol extract from distilled rose (Rosa damascena Mill.) petals (FDRPE) contribute uniquely to redox reactions. Although FDRPE exhibited the lowest total polyphenol content (TPC) and weakest antioxidant activity, its combinations with SLA and DHQ demonstrated enhanced radical scavenging and metal-chelating activities. Response surface methodology indicated that dihydroquercetin (DHQ) alone could achieve the strongest antioxidant activity but requires higher concentrations. The results suggest that the combined use of SLA, DHQ, and FDRPE positively impacts radical scavenging activity, as well as transition metal-chelating activity (FRAP and CUPRAC). The optimum is achieved by combining a 6.11962E-7 SLA + 88.5131 DHQ + 11.4869 FDRPE mg.L-1. The optimized mixture have the potential to be incorporated into various food matrices at lower concentrations compared to their individual use, enhancing the practical application in the food industry.