DEVELOPMENT AND OPTIMIZATION OF A DRINK UTILIZING CITRUS (CITRUS UNSHIU) PEEL EXTRACT

Abstract

ABSTRACTSCitrus (Citrus unshiu) peel extracts were utilized to develop a drink using a mixture design and optimization process. The contents of narirutin and hesperidin in the citrus peel extracts, as determined by high‐performance liquid chromatography, were 10.25 and 7.65 mg/g, respectively. Residual pesticides in the citrus peel, such as chlorobenzilate, diethofencarb, malathion, methiocarb and carbaryl, were not detected. Heavy metals, including lead (Pb) and cadmium (Cd), were determined as 16.00 and 6.55 µg/g prior to washing the citrus peels, and 5.83 and 5.83 µg/g after washing, respectively. Development of the drink with citrus peel extract was carried out using fructo‐oligosaccharide syrup and water. The interaction effects of these ingredients were investigated using a modified distance‐based design and analyzed by linear regression models, nonlinear regression models and trace plots. Optimization of the mixture ratio was determined with statistical modeling using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity, total flavonoid content and taste tests, all of which are important target constraints in a drink. Every constraint demonstrated a nonlinear canonical form. The response trace plot revealed that DPPH radical scavenging activity, total flavonoid content and taste tests were quite sensitive to citrus peel extract content in the drink. The optimal formulation of the drink was set at 1.974% citrus peel extract, 27.543% fructo‐oligosaccharide syrup and 70.364% water.PRACTICAL APPLICATIONSCitrus peels extract can be utilized to functional drinks having a narirutin and hesperidin. Mixture design and optimization process enables us to attain the optimal mixture ratio with drink ingredients for the drink. Numerical optimization process can be effectively applied in other food mixture systems.