Studi fisiologi pengerasan dan perubahan warna perikarp dalam hubungannya dengan respirasi klimakterik dan kadar air buah manggis (Garcinia mangostana) | Physiological study of hardening and color changes of pericarp in relation to climacteric respiration and moisture content in mangosteen (Garcinia mangostana) after harvest

Mangosteen is a high economic value fruit in Indonesia. The problems encountered are the fruit pericarp quickly harden and the color immediately changed to dark purple-black, and sepals quickly turned into brown in color after harvest, so shelf life is short, especially at room temperature. This research aimed to study the process of change in hardness, pericarp and sepal color, and the sepal freshness of the mangosteen fruit and the factors that influence the physiology and biochemistry during storage. The research consisted of five experiments: (1) hardening physiology of mangosteen pericarp, (2) effect of exogenous ethylene and storage temperature on quality changes of mangosteen, (3) effects of 1-methylcyclopropene (1-mcp) and storage temperature on hardening of and color change of pericarp of mangosteen, (4) Effect of cytokinin and CoSO4 on physical quality of mangosteen during cool storage, and (5) Effect of coating material and cytokinin CPPU (N-(2-chloro-4-pyridyl)-N-phenylurea (Forchlorfenuron)) on the quality of mangosteen on cool storage. The results showed that the peak rate of ethylene production one day earlier than the respiration climacteric. The peak rate of ethylene production occurred on day 11 while the respiration climacteric peak occurred on day 12. Climacteric respiration will lead to biochemical changes in the mangosteen fruit pericarp, such an increase in protein content, increased activity of the enzyme phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD), and increasing the amount of lignin. Pericarp hardening occured due to water content decrease in the mangosteen and increased content of lignin. Fruit stored at a temperature of 15oC can last up to 28 days after treatment (DAT). Whereas fruit stored at room temperature only last up to 14 DAT. Mangosteen fruit stored at a temperature of 15oC had lower level of resistance and hardness. had a higher water content, lower weight loss, slower color change, and had a higher total soluble solids (TSS) and titratable acidity (TA). Exogenous ethylene treatment did not provide a marked influence on all the variables observed, which means that the mangosteen fruit wass less sensitive to exogenous ethylene treatment. 1-MCP treatment at various doses did not prolong the shelf life of the mangosteen fruit. This treatment is consistent in both room temperature and at a temperature of 15oC. 6% beeswax better reduce weight loss than other types of coating materials.