Protocol development and optimisation for the extraction of hesperidin from citrus waste toward application in functional food packaging

Abstract

Abstract This study investigates the extraction and purification of polyphenols, particularly hesperidin (HE), from agro-industrial by-products such as orange stems and peels (OM). Pressurised liquid extraction (PLE) as extraction technique and macroporous resin adsorption as purification process were tested and optimized. PLE was performed using an accelerated solvent extraction system (30 mL) and subsequently scaled up to a Parr reactor (500 mL). PLE with water at 140 °C achieved approximately 88% of the HE yields obtained with 70% ethanol (14.0 vs. 15.9 mg/g DM) under identical conditions (15 min; S/L ratio, 1:20). Scale-up in a Parr reactor (140 °C, 5 min, S/L ratio 1:20) resulted in an extraction yield of 11.3 mg/g DM, corresponding to an efficiency of approximately 80% compared to the ASE system. These results confirm PLE as a sustainable alternative to conventional solvent extraction methods. For the purification step, seven resins were screened. Among the tested resins, XAD-7 exhibited the highest HE purity reaching 25.0 mg/100 mg extract and a concentration factor of 5.4. Polyphenol concentration and radical scavenging activity were enhanced by factors of 4.5 and 8.8, respectively, compared to the mother extract, while simple sugars were effectively removed. The adsorption of HE on XAD-7 followed a Freundlich isotherm (R² = 0.979) and a pseudo-second-order kinetic model (R² = 0.997). Dynamic mode adsorption achieved an adsorption capacity of 132.8 mg/g resin at a flow rate of 5 BV/h, with a breakthrough volume (VBT5%) of 25 BV (equivalent volume in mL) and a 50% saturation volume (Vs) of 54 BV. HE recovery exceeded 94%, with high HE purity (24.6 g/100 g extract). These results were consistent over three consecutive cycles. The overall process demonstrated high efficiency, offering a sustainable and scalable strategy for the recovery of valuable bioactive compounds from citrus by-products, thereby supporting their valorization in active packaging formulations or as functional food ingredients.