Sprout Suppression of Potato (Solanum tuberosum) Tubers Using Hydrogel for Prolonged Release of Citronella Essential Oil

Abstract

Sprouting and glycoside alkaloid induction usually occur in potato tubers, which are the main challenges in potato tuber storage. Essential oils bear the potential to inhibit potato sprouting, but their high volatility and instability limit their application. In this study, citronella essential oil (CEO) hydrogels were prepared by the ionic gelation method to enhance the sprout inhibition effect. The optimal conditions for the preparation of CEO hydrogels were sodium alginate (SA) concentration of 1.56%, CaCl₂ concentration of 2.26%, core-to-wall ratio of 2.02:1, and Tween-80 concentration of 0.15%. The SEM, FT-IR, XRD, and DSC images demonstrated that the CEO had been successfully encapsulated in hydrogels with improved thermal stability. CEO hydrogel slowly releases CEO within 1 week for sustained sprout inhibition. At 16 days of storage at 25 °C, the sprouting rate of the CEO hydrogel-treated potatoes was 42.06%, while that of the control check (CK) group was 100.00%, and at 180 days of storage at 3 °C, the sprouting rate was 10.83% in the treated potato tubers, while that of the CK group was 58.33%. The potato tubers treated with CEO hydrogel at either 3 or 25 °C maintained better quality. This indicated that CEO hydrogel can be used as a new potential potato sprout inhibitor in potato tubers.