Fruit Rind Peel as Promising Support Materials for Immobilizing Yeast Cells and Application in Repeated-Batch Cider and Wine Fermentation with Improved Aromatic Compound Profiles

This study aimed to valorize unqualified, unsold, and too mature melon fruit through cider and wine fermentation. <i>Saccharomyces cerevisiae</i> was immobilized on melon rind peel waste and used for repeated-batch fermentation. The immobilized yeast cells (IM-YC) at 10% loading produced alcohol higher than those at 30% and 50% loadings. The fermentation cycle time of 24 h gave an alcohol concentration of 5.0-5.5%, which could be categorized as cider. With longer fermentation cycle time of 48 h, yeast cells produced more alcohol, up to 12.50 ± 0.71%, which was categorized as wine. Volatile component analysis through GC-MS showed that the fermentations using IM-YC on rind peel had stronger fruit aroma and distinct characteristics when compared to those using free cells. These strategies not only help reduce the inoculum preparation cost but also increase the efficiency and aromatic profiles of cider and wine products, and may greatly contribute to the sustainable food industry.