ASSESSMENT OF THE ANTIFUNGAL EFFICACY OF GINGER RHIZOME (Zingiber officinale L.) EXTRACT ON Aspergillus sp. ISOLATES FROM PURPLE SWEET POTATO MOCHI

Abstract

Purple sweet potato mochi, a traditional product combining glutinous rice cake with purple sweet potato, is characterized by high nutritional value and elevated moisture content. However, its soft and elastic structure, together with high water activity, provides favorable conditions for microbial spoilage, particularly mold contamination. Developing safe and effective preservation strategies from natural sources has therefore become an important research focus. The present study aimed to evaluate the antifungal potential of ginger extract against mould isolated from spoiled purple sweet potato mochi. A spoilage mold strain was isolated and identified through sequencing, revealing 97.26% similarity to Aspergillus niger strain WM 10.75 (OR195800.1) in the GenBank database. In vitro antifungal assays were conducted to assess the inhibitory effects of ginger extract on both mycelial growth and spore germination of the isolate. The results demonstrated that ginger extract exhibited significant antifungal activity. Complete inhibition of mycelial growth was observed at a concentration of 1000 µg/mL after 168 hours of cultivation. Furthermore, spore germination was effectively inhibited at a concentration of 4 mg/mL after 48 hours of cultivation. Overall, these findings indicate that ginger extract possesses strong inhibitory activity against A. niger under in vitro conditions. This highlights its potential application as a natural antifungal agent for extending the shelf life and ensuring the fungal safety of purple sweet potato mochi.