Optimization of Phenolic Compound Extraction from Pineapple Leaf Fiber: Stability Enhancement and Application in Mango Preservation

Focusing on the challenges of low utilization of pineapple leaves and the poor stability of phenolic compounds (PCs) in pineapple leaf fiber using traditional solvent extraction methods, the effects of different extraction media (including distilled water, neutral methanol, acidic methanol, alkaline methanol, neutral ethanol, and alkaline ethanol) was systematically investigated on the extraction efficiency of PCs from pineapple leaf fiber. Through response surface methodology (RSM), the optimal extraction conditions were determined. Additionally, the impacts of illumination and pH on the stability of PCs in pineapple leaf fiber were thoroughly examined. The results demonstrated that acidic ethanol outperformed other extraction media, with the optimized extraction conditions as follows: ethanol concentration = 80%, material-to-liquid ratio = 1:40, extraction temperature = 70 °C, and extraction time = 40 min. Under these conditions, the extraction yield of PCs reached 11.55 mg/g. Furthermore, the stability of PCs was significantly enhanced by minimizing light exposure and maintaining a pH range of 3–6. The potential application of PCs extracted from pineapple leaf fiber was also explored, particularly in mango preservation, revealing promising results. This study not only provides an efficient and sustainable approach for the extraction and stabilization of PCs from pineapple leaf fiber but also opens new avenues for the utilization of polyphenols in functional applications, contributing to the valorization of agricultural by-products.