Effect of chitosan and gum Arabic with natamycin on the aroma profile and bacterial community of Australian grown black Périgord truffles (Tuber melansoporum) during storage

This study aimed to assess the effect of chitosan or gum Arabic edible coatings, with natamycin (200, 300, 400 mg/L) on the aroma profiles of Western Australian grown truffles at five storage intervals: 0, 7, 14, 21, and 28 days using solid-phase microextraction (SPME)-followed by gas chromatography-mass spectrometry (GC-MS). The population structure of the bacterial community of both untreated and chitosan-natamycin (400 mg/L) coated truffles were assessed using metagenomic sequencing analysis alongside GC-MS. The results demonstrated that all the coating treatments were able to have a positive impact in halting or delaying the changes of truffle aroma throughout the storage period, with chitosan-natamycin (400 mg/L) coating having the best preservation results compared to the other coatings. Only 9 volatile organic compounds (VOCs) were found to have significant changes in chitosan-natamycin (400 mg/L) coated truffles throughout the storage period compared to 11 VOCs in untreated controls. The result also demonstrated the gradual change of fresh truffle's bacteria communities over the storage period. Over 4 weeks of storage, the dominant bacterial classes of the truffles (α-Proteobacteria, Bacteroidia or Actinobacteria classes) were replaced by Bacteroidia, Actinobacteria, Deltaprotobacteria and γ-Proteobacteria classes. The preliminary results from this study show that edible coatings can affect the VOC and bacterial communities of the truffles which may have implications for future research into truffle preservation techniques.