Multivariate Analysis of the Efficiency of Bio-Actives Extraction from Laboratory-Generated By-Products of Citrus reticulata Blanco

A growing demand for sustainable methods to valorize agricultural by-products underscores the need for efficient,
green extraction techniques. This study evaluated ultrasound-assisted extraction (UAE) of bioactive compounds from Citrus
reticulata Blanco peel and pomace using multivariate analysis across six key metrics: total phenolic content (TPC), flavonoid
content, and four antioxidant assays. UAE significantly outperformed conventional extraction (CE), achieving a 207% higher
average composite performance score (2.94 vs. 0.95), on the basis of a heatmap-derived SUM(P*) index. The best UAE sample
(S9: peel–aqueous–UAE) achieved a score of 5.33 out of 6, compared to 2.01 for the best CE sample (S3), highlighting the superior
efficiency of UAE. Principal component analysis (PCA) revealed distinct clustering of UAE samples, confirming their enhanced
biochemical profiles. UAE also reduced energy consumption to 0.065 kWh (77% less than CE) while maintaining high antioxidant
performance. Fourier transform infrared spectroscopy (FTIR) confirmed functional groups characteristic of phenolics, and ultra-
high performance liquid chromatography (UHPLC)–HRMS identified catechin, neohesperidin, and nomilinic acid derivatives as
major bioactives. These findings establish a robust, data-driven framework for optimizing sustainable extraction of food-grade
antioxidants from citrus residues. This validated UAE approach enables efficient, low-energy recovery of phenolics from citrus
waste, offering immediate potential for integration into food, nutraceutical, and cosmetic industry supply chains under circular
economy models.