Identifying dominant spoilage fungal species and preservative treatments for extending shelf life of whole lotus rhizomes at 4 °C

A preservative for whole lotus rhizome preservation was developed under 4 °C storage in this study. The study included the following steps: Firstly, isolation and identification of spoilage causing fungi of lotus rhizome, and four main spoilage causing fungi were identified, including Penicillium solitum, Geotrichum silvicola, Phytopythium helicoides, and Pseudeurotium zonatum. Secondly, selection of antifungal agent with good inhibitory ability against the above four spoilage causing fungi, finally 0.5 % potassium sorbate was selected considering edible security at the same time. Thirdly, the selection of suitable color fixative according to the indexes of root skin and flesh color differences, and sensory evaluation. The final color fixative composition: EDTA-2Na (8 g/L), ascorbic acid (8 g/L), and d-isoascorbic acid sodium (6 g/L). Finally, the antifungal agent and color fixatives were mixed to make the preservative. Soaked in preservative for 20min, drained and packed into PE bags, vacuumed and stored at 4 °C, the lotus rhizomes could maintain better color, got high sensory score, soluble solids content, and total acid content, and the microbial counts were always lower than the untreated group. The preservative could extend the shelf life of whole lotus rhizome to about 50 d at 4 °C. •Four dominant spoilage fungal species of whole lotus rhizomes were isolated and identified.•A preservative for whole lotus rhizomes under 4 °C storage has been developed.•The preservative has good antifungal and color protection effects.•The shelf life of whole lotus rhizomes can be extend to 50 days under 4 °C storage.