453 Effect of Edible Coating on the Qualities of Fresh Guava R. Sothornvit a Department of Food Engineering, Faculty of Engineering at Kamphaengsaen/PHTIC/ Center of Advanced Studies in Industrial Technology/ Center of Excellence for Agricultural and Food Machinery Kasetsart University, Kamphaengsaen Campus Nakhonpathom 73140 Thailand Keywords: beeswax, glucomannan, guava leaf extract Abstract Guava is a perishable fruit. Edible coating might help prolonging the quality of guava. The objective of this study was to determine the effect of glucomannan (G) or konjac edible coating incorporated with beeswax (BW) and guava leaf extract (E) on the quality of fresh guava compared with water coating (W) and control (C) or uncoated stored at room temperature (29 ๐ C) and 95% RH. It was found that guava coated with GBW significantly reduced weight loss and firmness (p<0.05) and extended the shelf-life of guava for 13 days compared with uncoated guava. Water coated guava had higher weight loss compared with uncoated guava. Total soluble solid (TSS) of guava increased significantly in all coating types (p<0.05) during storage. Guava coated with water had the highest TSS. The pH of guava increased during storage and it depended on edible coating types as well. However, the hue angle value of guava had a significant decrease during storage (p<0.05). Using either beeswax or guava leaf extract alone to the glucomannan edible coating might extend the shelf-life of fresh guava. However, the combination of beeswax and guava leaf extract based-glucomannan edible coating did not enhance significantly on the quality shelf-life of fresh guava. INTRODUCTION Guava is an important tropical fruit and rich in dietary fiber, vitamin A and C. The commercial aspect of guava is its natural flavor and aroma which is related to the phenolic, flavonoid, carotenoid, terpenoid and triterpene contents (Gutierrez et al., 2008). Guava is highly perishable resulting in a short shelf life due to its high rate of ripening (Pantastico et al., 1975). Moreover, the guava leaf extract showed the antioxidant activity due to its ability in free radical scavenging and reducing of oxidized intermediates (Tachakittirungrod et al., 2007). Furthermore, a high level of antibacterial activity was found (Hidetoshi and Danno, 2002; Mahfuzul Hoque et al., 2007; Gutierrez et al., 2008) and has been used as medical treatments for diarrhea in terms of antiseptic (Teixeira et al., 2003). Edible films and coatings are alternative approaches due to their properties on water and gas barrier and desirable mechanical protection for food products. Glucomannan (konjac) is a polysaccharide which is renewable, economical, readily available, biodegradable and highly safe for used in food and biomedical applications (Wang and He, 2000) due to its properties as a barrier to water and gases including control drug delivery. Glucomannan has been incorporated to form good film with other components such as gelatin (Li et al., 2006a), chitosan and nisin (Li et al., 2006b), carboxymethyl cellulose (Cheng et al., 2008), chitosan and soy protein isolate (Jia et al., 2009), sericin (Sothornvit and Chollakup, 2009) or as a binder for activated carbon incorporated into rice straw paper (Sothornvit and Sampoompuang, 2011). Coating material containing konjac glucomannan was used to preserve fresh produce such as cantaloupes, apples, etc. to control respiratory exchange; for example, the transfer of a fengrns@ku.ac.th Proc. 7 th International Postharvest Symposium Eds.: H. Abdullah and M.N. Latifah Acta Hort. 1012, ISHS 2013