JUSTIFICATION OF OPTIMAL EXTRACTION PARAMETERS OF BIOACTIVE SUBSTANCES FROM CITRUS PEEL WASTE

Different parts of citrus fruit may be s source of vitamins, minerals, antioxidants, and dietary fiber that are essential for a balanced diet. The phytochemicals can have positive effects on human health. The antimutagenic, antioxidant, anticarcinogenic, anti-inflammatory and anti-aging effects of citrus phytochemicals have been established, these bioactive substances could promote the cardiovascular functions and the nervous system. The purpose of this research was to develop optimal parameters for the extraction of biologically active compounds from the citrus peel waste (CPW) of various citrus species. Bioactive substances were extracted from the CPW of sweet orange and grapefruit by the traditional maceration method using the ethanol of various concentrations as a solvent. Superoxide anion radical activity from CPW extracts with different concentrations of ethanol varied significantly. For grapefruit peel extract samples, at an ethanol concentration of 70 %, the ability to neutralize free radicals was the highest and reached 87 %. At ethanol concentration of 70 %, the yield of polyphenols from CPW was the highest, the total polyphenol content for orange peel reached 4.55 mg GAE/g, and the highest yield of grapefruit peel polyphenols amounted to 4.43 mg GAE/g. With increasing ethanol concentration, the migrations of polyphenols from the peel to extracts gradually decrease. At ethanol concentration of 90 %, orange peel showed the highest flavonoid yield of 1.7371 mg EQ/g. For grapefruit peel, at an ethanol concentration of 70 %, the maximum flavonoid yield was 1.0062 mg EQ/g.