Degreening dan Penyimpanan Suhu Rendah untuk Meningkatkan Mutu Jeruk Gerga Pagar Alam (Citrus nobilis SP.)

Abstract

Jeruk RGL (Rimau Gerga Lebong) merupakan salah satu jenis jeruk yang berkembang di kota Pagar Alam, Sumatera Selatan. Jeruk ini biasa dikenal dengan jeruk Gerga. Jeruk Gerga pertama kali dibudidayakan di kota Pagar Alam pada tahun 2013. Ketika matang secara fisiologis warna kulit jeruk Gerga Pagar Alam masih kuning kehijauan dan memiliki umur simpan yang relatif pendek. Perlakuan degreening dan penyimpanan suhu rendah berpotensi meningkatkan mutu fisik jeruk Gerga Pagar Alam bila dilakukan dengan tepat. Teknologi degreening dapat meningkatkan warna kulit buah jeruk menjadi kuning atau jingga merata. Selain itu dengan adanya penyimpanan suhu rendah diharapkan dapat memperpanjang umur simpan buah jeruk Gerga Pagar Alam. Penelitian ini bertujuan untuk mengkaji pengaruh degreening dan penyimpanan suhu rendah jeruk Gerga Pagar Alam terhadap perubahan fisikokimia dan menentukan metode degreening dan penyimpanan suhu rendah yang optimum terhadap mutu jeruk Gerga Pagar Alam. Penelitian ini dilaksanakan pada bulan Desember 2021 sampai dengan bulan Januari 2022. Tempat penelitian di Laboratorium Teknik Pengolahan Pangan dan Hasil Pertanian (TPPHP) Fakultas Teknologi Pertanian Institut Pertanian Bogor. Sedangkan jeruk Gerga dipanen langsung dari kebun petani di Kelurahan Agung Lawangan, Kecamatan Dempo Utara, Kota Pagar Alam, Sumatera Selatan. Penelitian ini menggunakan rancangan acak lengkap dua faktorial dengan tiga kali ulangan. Faktor pertama yaitu degreening dengan 4 taraf konsentrasi ethepon 0 ppm (E0), 250 ppm (E250), 500 ppm (E500), 750 ppm (E750). Faktor kedua yaitu suhu penyimpanan 3 taraf yaitu suhu 10 ºC (T10), 20 ºC (T20) dan suhu ruang (TR). Parameter yang di uji terdiri dari warna, susut bobot, persentase buah busuk, kekerasan, total padatan terlarut, total asam dan vitamin C. Hasil penelitian menunjukkan degreening berpengaruh nyata terhadap perubahan warna kulit jeruk Gerga Pagar Alam. Perlakuan degreening (konsentrasi ethepon 250 ppm, 500 ppm, 750 ppm) menghasilkan nilai CCI sebesar 3,48-3,82 membentuk warna kulit menjadi kuning merata pada akhir penyimpanan ( pengamatan hari ke-29). Perlakuan suhu 10 oC efektif menekan susut bobot selama penyimpanan, sehingga dapat memperpanjang umur simpan sampai dengan hari ke- 29 penyimpanan. Kombinasi perlakuan degreening konsentrasi ethepon 250 ppm dan suhu 10 oC dan 20 oC dapat mempertahankan mutu jeruk Gerga Pagar Alam dengan susut bobot terendah pada pengamatan hari ke-14, mengurangi kekerasan pada kulit dan mempertahankan kandungan vitamin C pada pengamatan hari ke-29. Hasil uji organoleptik menunjukkan perlakuan degreening dan suhu penyimpanan meningkatkan kesukaan panelis terhadap warna. Perlakuan suhu meningkatkan kesukaan panelis terhadap aroma, tekstur dan rasa.

RGL (Rimau Gerga Lebong) is a type of citrus that grows in the city of Pagar Alam, South Sumatra. This orange is commonly known as the Gerga orange. Gerga oranges were first cultivated in the city of Pagar Alam in 2013. When physiologically ripe, the skin color of Gerga Pagar Alam oranges is still greenish- yellow and has a relatively short shelf life. Degreening treatment and low- temperature storage have the potential to improve the physical quality of Gerga Pagar Alam oranges if done properly. Degreening technology can increase the skin color of citrus fruits to become uniformly yellow or orange. In addition, the presence of low-temperature storage is expected to extend the shelf life of Gerga Pagar Alam oranges. This study aims to examine the effect of degreening and low-temperature storage of Gerga Pagar Alam oranges on physicochemical changes and to determine the optimum degreening and low-temperature storage methods for the quality of Gerga Pagar Alam oranges. This research was conducted from December 2021 to January 2022. The research location was the Food and Agricultural Products Processing Engineering Laboratory (TPHPP), Faculty of Agricultural Technology, Bogor Agricultural University. Meanwhile, Gerga oranges are harvested directly from farmers' gardens in Agung Lawangan Village, Dempo Utara District, Pagar Alam City, South Sumatra. This study used a two-factorial completely randomized design with three replications. The first factor was degreening with 4 ethepon concentration levels of 0 ppm (E0), 250 ppm (E250), 500 ppm (E500), 750 ppm (E750). The second factor is the storage temperature of 3 levels, namely temperature 10 ºC (T10), 20 ºC (T20), and room temperature (TR). The parameters tested consisted of color, weight loss, percentage of rotten fruit, hardness, total dissolved solids, total acids, and vitamin C. The results showed that degreening had a significant effect on changes in the color of Gerga Pagar Alam's orange peels. Degreening treatment (ethepon concentrations of 250 ppm, 500 ppm, 750 ppm) resulted in a CCI value of 3.48- 3.82, forming an even yellow skin color at the end of storage (29th day of observation). The temperature treatment of 10 oC effectively suppressed weight loss during storage, thereby extending the shelf life up to the 29th day of storage. The combination of degreening treatment with an ethepon concentration of 250 ppm and temperature of 10 oC and 20 oC maintained the quality of Gerga Pagar Alam oranges with the lowest weight loss on the 14th day of observation, reduced skin hardness and maintained vitamin C content on the 29th day of observation. The organoleptic test results showed that the degreening treatment and storage temperature increased the panelists' preference for color. Temperature treatment increased panelists' preference for aroma, texture, and taste.