[4-1330-A] Postharvest/Food Technology and Process Engineering (2)

[4-1330-A-07] Antifungal Packaging for Prolonging Shelf Life of Table Grapes

*SIRIPORN LUESUWAN¹ (1. MAE FAH LUANG UNIVERSITY(Thailand))

Keywords:Table grape, Essential oil, Antifungal packaging, Pathogenic fungi

The table grape (Vitis vinifera cv. ‘Beauty seedless’) becomes popular fruit in Thailand because it’s seedless and sweet. The fungal decays in table grapes from Botrytis cinerea, Penicillium spp., Aspergillus spp., and Rhizopus stolonifera (soft-rot mold) are the main postharvest problems. To dissolve this problem for grapes exportation and distribution, many countries usually used sulfur dioxide (SO₂) fumigation in sachet and pad forms for inhibiting the fungal growth. However, the sulfur dioxide fumigation is not accepted in many countries because sulfur dioxide residues are potentially hazardous to human health. So, this research was studied about the new antifungal packaging for delaying the mold growth in table grapes by using natural essential oils. The concentration of essential oils (clove, cinnamon, thyme, peppermint, lemon, bergamot, ginger, spearmint, and lemongrass oils) at 0.5, 1, 2 and 5% (w/v) were used for screening the antifungal property against Aspergillus spp. by using the disk diffusion method, minimal inhibitory concentration (MIC) assay, minimal fungicidal concentration (MFC) assay, and determination of radial growth. The results showed that the clove, cinnamon and lemongrass oils could inhibit the growth of Aspergillus sp. In part of sensory evaluation by untrained panelists, they were accepted the odor of clove oil when apply in grape. So, clove oil was selected to use in application part. In application, grapes were packed into perforated polypropylene (PP) bag and devided into 5 groups; (i) without essential oil (control), (ii) with the essential oil in absorbent pad, (iii) with oriented polypropylene (OPP) film coated 7% polyvinyl alcohol mixed with essential oil, (iv)with OPP film coated 7% polyvinyl alcohol mixed with essential oil and 1% halloysite clay, and (v) commercial sulfer dioxide pad. The 300 grams of table grapes were packed and stored at 14 °C, 75 %RH for 30 days. The weight loss and sensory evaluation of table grapes were determined every 3 days. The results showed that all of treatments could delay the growth of the pathogenic fungi except control. The OPP film coated 7% polyvinyl alcohol mixed with essential oil with and without halloysite clay could prolong shelf life of table grapes for 21 days. While control, perforated PP bag with the essential oil absorbent pad and commercial pad could prolong shelf life of table grape for 12, 15, and 18 days respectively.