Development of coating materials for tangerine fruits
1993
Preeda Chittarom
Two coating materials for tangerine (Citrus reticulata Blanco cv. Khieo Wann) fruits formulated from natural waxes; carnauba 0 to 15 % and shellac 0 to 20 % in water were compared with a commercial wax "Johnson's was". Carnauba formulations reduced weight loss up to 60 % while allowed free gas exchange through the peel resulting in similar internal O2 and CO2 concentrations with the uncoated fruits. Shellac formulations reduced weight loss by only 20 % regardless of wax concentrations. However gas exchange were restricted through the peel, resulting in higher internal CO2 and lower O2 concentrations and corresponded with higher ethyl alcohol content in the head space of the juice when higher concentrations of shellac were used. "Johnsons wax" 100 % gave similar result with 10 % carnauba. Soluble solids content, titratable acidity and ascorbic acid content of tangerines in all waxed or nonwaxed fruits were not significantly different. When both waxes were coated on silk screen cloth for O2 and CO2 permeability measurement, higher concentration of shellac restricted more gas permeabilty, but for carnauba only the 15 % concentration had some gas permeability restriction. The properties of mixture of carnauba and shellac formulated at 12 % concentration were found to be mainly in between the properties of the two waxes. The gloss of carnauba+shellac-coated fruits was less than those coated by carnauba or shellac, respectively. The effect of these waxes on taste, texture and chemical composition of tangerines were not significant.
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