Penggunaan gas karbon dioksida untuk menurunkan kadar tanin buah kesemek (Diospyros kaki L.) kultivar Reundeu

Abstract

Buah kesemek kultivar Reundeu merupakan buah subtropis tipe astringent yang dikelola secara tradisional di Indonesia. Kandungan tanin yang tinggi menyebabkan buah akan tetap sepat meskipun telah matang di pohon. Untuk mencapai standar secara komersial diperlukan penanganan pascapanen untuk menghilangkan rasa sepat buah. Penelitian ini bertujuan; 1) Menganalisis efektifitas penggunaan gas CO2 untuk menurunkan kadar tanin buah kesemek dengan menentukan kombinasi dosis dry ice dan waktu perlakuan yang optimum pada tiga tingkat kematangan buah selama deastringency treatment, 2) Menganalisis perubahan fisikokimia dan fisiologi buah setelah deastringency treatment. Buah kesemek dimasukkan dalam stoples dengan perlakuan dosis dry ice (10 g, 20 g, 30 g dan kontrol) pada kondisi suhu ruang. Pengukuran konsentrasi gas CO2 awal dilakukan setelah dry ice dalam stoples bersublimasi. Selanjutnya dilakukan proses deastringency treatment selama (24, 48 dan 72 jam) dan pengukuran gas CO2 akhir. Setelah treatment, buah dibiarkan pada suhu ruang selama 3, 6, 9 dan 12 hari. Pengukuran kuantitatif mencakup susut bobot, warna, kekerasan, total padatan terlarut, total asam, vitamin C dan kadar tanin dilakukan selama pre treatment, deastringency treatment dan post treatment.

Persimmon (Diospyros kaki L.) cv. Reundeu is a subtropic fruit of astringent type that harvested traditionally in Indonesia. High tannin content causes the fruit remains astringent despite having been matured in the tree. To meet the commercially standard, it is needed to remove the astringent taste of the fruit. The study aimed; 1) To analyze the effectiveness of carbon dioxide gas in reducing tannin content in persimmon by determining combination of dry ice dose and exposure time at three maturity level during deastringency treatment, 2) To examine the physicochemical and physiology change of fruit after deastringency treatment. Persimmon fruits were put into jar and treated by various doses of dry ice (10 g, 20 g, 30 g and control) at ambient temperature condition. Measurement of initial concentration of carbon dioxide gas was carried out after dry ice in the jar sublimed. Deastringency treatments were applied for 24, 48 and 72 hours and the measurements of final concentration of carbon dioxide gas were carried out after treatment period. Furthermore, the fruits placed at room temperature for 3, 6, 9 and 12 days. The changes in weight loss, color, firmness, total soluble solid, total acid, vitamin C and tannin content were measured during pre treatment, deastringency treatment and post treatment.