Caffeic acid-grafted chitosan/polylactic acid packaging affects bacterial infestation and volatile flavor of postharvest Agaricus bisporus

Abstract

To clarify the effect of caffeic acid-grafted-chitosan/polylactic acid (CA-g-CS/PLA) packaging on the bacterial infestation and volatile flavor of postharvest Agaricus bisporus, electronic nose (E-nose) combined with gas chromatography-mass spectrometry (GC–MS) analysis was utilized to detect the volatile flavor. 16s rDNA sequencing technology was used to determine the species and changes of bacterial flora on the surface of Agaricus bisporus. The correlation between volatile flavor substances and bacterial communities was analyzed. The results showed that compared with polyethylene (PE) packaging, CA-g-CS/PLA packaging significantly delayed the loss of characteristic volatiles such as 1-octene-3-ol, 3-octanol, 3-octone and the ability to inhibit the growth of total bacteria count (TBC) was elevated by 12.6 % at 15 d of storage. Moreover, CA-g-CS/PLA packaging significantly reduced the abundance of spoilage bacteria such as Flavobacterium, Pedobacter and Pseudomonas compared to PE packaging and the sum of the three fell from 38 % to around 8 %. The correlation analysis showed that spoilage bacteria were significantly negatively correlated with 1-octene-3-ol and 3-octone and significantly positively correlated with spoil flavors such as benzaldehyde, indole and naphthalene. These results indicated that CA-g-CS/PLA packaging could delay the deterioration of the postharvest volatile flavor of Agaricus bisporus by inhibiting the abundance of specific spoilage bacteria.