Evaluation of Ozone and Sodium Metabisulfite Treatment on postharvest grapes quality and Rhizopus Disease control

Abstract (in English)

Table grapes are important fruit crops subjected to fungal decay during harvesting, post-harvest handling, and storage. An investigation was made on the in-vitro evaluation of ozone (O₃) and Sodium metabisulfite (SMB) against radial growth of R. stolonifer by fumigation and food poisoning techniques, respectively. In another experiment, in-vivo evaluation of O₃ fumigation at various concentrations and SMB at different doses were tested against Rhizopus rot in table grapes under cold storage. The results revealed that O₃ at 8833.2 µl L^-1 and SMB at 90 mg /100ml PDA significantly inhibited radial growth of R. stolonifer by 94.82%, and 98.14 %.  Disease severity was zero in both O₃ and SMB treated fruits but it was 0.89 DS in inoculated control, O₃ at 7274.4 µL L^-1 showed significantly better retention of berry firmness (85.09N) and ascorbic acid (3.90 mg/100 g) and least TSS (18.68 N), and PLW (7.49) and also scored highest sensory overall acceptability (8.04). SMB powder 0.5g among SMB treated fruits following O₃ showed appreciative results. In addition, SMB treatments showed significantly highest L*and b* values highest compared to ozone, and recorded the least colour a* value. Hence, ozone is a good alternative to SO₂ treatments in conventional grape production and it could be a suitable technology to control Rhizopus rot and maintain the quality parameters of grapes in cold storage.