Perubahan Kualitas Beras Selama Penyimpanan (Change of Rice Quality During Storage)

Abstract

Penyimpanan merupakan tahap yang menentukan dalam menjamin ketersediaan beras berkualitas. Selama penyimpanan, beras mengalami penyusutan kualitas dan kuantitas yang disebabkan oleh perubahan fisik, kimia, dan biologi. Penelitian ini bertujuan untuk mengamati perubahan kualitas beras selama penyimpanan. Aspek yang diamati adalah kadar air, butir kepala, menir, patah, dan kuning, serta water uptake dan pertumbuhan kutu beras (Sitophilus oryzae). Dalam penelitian ini digunakan tiga jenis beras, yaitu yang mendekati SNI Mutu III (jenis A) dan IV (jenis B), serta yang tidak memenuhi standar SNI (jenis C). Beras ditempatkan dalam karung plastik berisi 15 kg dan disimpan pada keadaan ambient (temperatur 29–32°C dan kelembaban 65–95 persen). Kualitas beras diamati setiap 15 hari, sedangkan pertumbuhan kutu diamati setiap minggu. Hasil menunjukkan bahwa kadar air beras jenis A dan B, dengan nilai awal < 13,5 persen, mengalami kenaikan 0,03 persen/hari sampai mendekati 14,5 persen, sementara jenis C, dengan kadar air awal 15,5 persen, relatif konstan. Beras berkadar air > 14 persen mengalami degradasi akibat reaksi Maillard dan penjamuran yang mengakibatkan warna kuning, penurunan water uptake, serta meningkatnya butir patah dan menir. Selain itu, populasi kutu meningkat dengan kecepatan 3 ekor/100g beras/minggu. Kesimpulan dari penelitian ini adalah kadar air beras yang disimpan harus < 14 persen, dan kelembaban udara di unit penyimpan harus dijaga serendah mungkin (< 65 persen).

Storage is a crucial stage in ensuring the availability of quality rice. During storage, rice quality and quantity decrease as a cause of changes in physical, chemical, and biological processes. This study is aimed to observe the changesb of rice quality during storage. The quality components measured are moisture content, whole kernel, broken kernel, chips, yellow kernel, water uptake, and the growth of rice weevil (Sitophilus oryzae). Three types of rice are used, namely that meet SNI Quality III (type A) and IV (type B), and that does not meet SNI standard (type C). The rice is placed in plastic bags with 15 kg of rice in each bag and stored at ambient conditions (29–32°C and relative humidity of 65–95 percent). Quality of the rice is observed every 15 days, while the growth of weevil is observed every week. The results show that moisture content of rice types A and B, with initial value < 13.5 percent, increases with a rate of 0.03 percent/day, while type C, with initial moisture content of 15.5 percent, is relatively constant. The increase of moisture content causes the rice to be degraded due to the Maillard reaction and mould that yield yellowing, decrease of water uptake, and increase of broken kernel as well as chips. It is also observed that the number of weevil increases during storage with the growth rate of 3 weevils/100g of rice/week. The conclusion of this research is that the initial moisture content of rice to be stored should be < 14 percent, and the humidity of the air in storage room must be kept as low as possible (< 65 percent).