III. MATERIALS AND METHODS
3.1. Time and Place
The research was done at Postharvest Laboratory, Faculty of Agriculture, Laboratory of Food and Agricultural Product Process Engineering, Laboratory of
Environmental and Agricultural Building, Faculty of Agricultural Technology, Bogor Agricultural University IPB, starting from February 2010 to May 2010.
3.2. Plant Material and Treatment
The research was divided into two stages. The first experiment covered physical and chemical changes of mangosteen fruit treated with CPPU and CoSO
4
during storage, while the second one involved the study of physiological and its relation to color development of mangosteen fruit treated with CPPU and CoSO
4
during storage. The experimental design was arranged in a completely randomized block design with 2 factors and 3 replications. The first factor was cobalt sulphate
CoSO
4
at four concentrations 0, 500, 1000, and 2000 ppm, while the second one was CPPU at four concentrations 0, 10, 20, and 30 ppm. The combination of
the above factors provided 16 treatments with 48 experimental units. Each experimental unit comprised 40 mangosteen fruit. For the second experiment, the
design was as in the first experiment, but only cobalt sulphate at 0, 2000 ppm, and CPPU at 0, 30 ppm were used with 5 mangosteen fruit per experimental unit.
The fruits used in the experiment were harvested from local orchard Purwakarta at stage 1light greenish yellow with 5-50 scattered spots on the
same day and were of similar sizes. The harvested fruit were transported at night to Postharvest Laboratory. In the following morning, fruit were sorted, and
washed with tap water to remove the dust. After washing, the fruit were air dried, and then treated with solution of fungicide TBZ 1 ppm for 30 seconds and air
dried. Following fungicide application, air-dried fruit were dipped in the solution of CoSO
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and CPPU for 30 seconds according to its concentrations used in the treatments. To facilitate the absorption of the solution by fruit, Tween 20 1
was added. After application, treated fruits were air dried, then immediately stored at 14-16
o
C 76-96 RH which is an ideal storage temperature for mangosteen fruit.
3.3. Observed Variables
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