Sulfite-free treatment combined with modified atmosphere packaging to extend trimmed young coconut shelf life during cold storage

Abstract

Sulfite solution has been commonly used on trimmed young coconut (TYC) and other produce to prolong shelf life, but it has been banned in many countries due to its allergenic reaction in sensitive individuals. This study has developed sulfite-free treatment together with modified atmosphere packaging (MAP) which could prolong shelf life of TYC during cold storage. The main goal of this work was to investigate qualities during cold storage at 2 °C for 8 weeks of TYC treated with salt/acid solution (15% sodium chloride and 20% citric acid) then packed in MAP at an oxygen transmission rate (OTR) of 3200 cm3/m2/day (SA-MAP), compared with a conventional sulfite agent treatment (KMS wrapped with PVC). Moreover, microbial profiles were investigated by next-generation sequencing (NGS), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 18S rRNA gene sequencing. The result showed treatment of SA-MAP had effective control TYC qualities over 8-week storage comparable with the KMS treatment. Twelve genera of bacterial communities on TYC including Bacillus spp., Enterococcus sp., Enterobacter spp., Klebsiella sp., Kocuria sp., Lysinbacillus sp., Microbacterium sp., Micrococcus sp., Ochrobactrum spp., Pantoea spp. Staphylococcus spp. and Serratia sp. were the most abundant strains. On the other hand, microbial profiles of SA-MAP showed only Bacillus spp., Staphylococcus spp. and Candida spp. as the predominant microorganisms on TYC during cold storage. Using salt/acid combined with MAP was proposed as an alternative organic treatment to extend the shelf life of TYC for exportation.