Effication of Local Propolis as Edible Coating of Tangerine cultivar Garut (Citrus reticulata Blanco)

Abstract

The tangerine var. Garut (Citrus reticulata Blanco) is one of the promising local Indonesia fruit commodity. In order to penetrate to new markets, extended shelf life is a necessity. Concern on the energy cost and health made application of natural products as coating material as the best option for post-harvest protection. This research focused on examining the effectiveness of local propolis as the coating material for tangerine var. Garut. The propolis used in this study originated from Trigona laeviceps farm in Maribaya, West Java. Propolis was extracted with propylene glycol solvent. Propolis extract then diluted in propylene glycol to produce extracts with concentration 5%, 10%, and 15% and applied as biocoat of the tangerine by dip method for a minute. Fruits washed by ethanol 70% in a minute were designated as positive control and fruits without any treatment as the negative control. All fruits were stored in room temperature for 34 days. Measurement of weight and diameter, the firmness of mesocarp and endocarp, the temperature of the rind and the flesh, and content of sucrose, total soluble solids, and vitamin C conducted every 3 days. At the same time, digital pictures were taken to observe the changing of color pigment on the fruit skin. Observation of physical and chemical characteristics of fruit showed that propolis coating maintained endocarp firmness, diameter, and vitamin C level for also delayed the decaying process 20% longer than the control with the best concentration for application was 10%.