No abstract

No abstract

ABSTRAKTribolium castaneum merupakan serangga hama penting pada penyimpanan beras di Indonesia. Penelitian ini bertujuan menguji perbedaan jumlah pasangan T. castaneum terhadap spesies dan populasi cendawan pascapanen pada beras selama penyimpanan dan pengaruhnya terhadap kadar air dan susut bobot beras. Beras ditempatkan di dalam stoples (250 g/stoples) dan diinfestasi dengan 5, 10, dan 20 pasang T. castaneum. Sebagai kontrol, stoples hanya berisi beras. Setiap perlakuan (termasuk kontrol) dibuat tiga ulangan. Penyimpanan dilakukan selama 1, 2, dan 3 bulan pada kondisi laboratorium. Kadar air (berdasarkan bobot basah) ditentukan menggunakan metode oven. Isolasi cendawan dilakukan dengan metode pengenceran yang dilanjutkan dengan metode cawan tuang pada medium Dichloran 18% glycerol agar. Susut bobot (berdasarkan bobot kering) beras ditentukan setelah 3 bulan penyimpanan. Hasil penelitian menunjukkan bahwa populasi imago T. castaneum semakin meningkat dengan bertambahnya jumlah pasangan T. castaneum yang diinfestasikan dan lama penyimpanan. Kadar air beras relatif konstan selama penyimpanan dan diduga lebih banyak dipengaruhi oleh kondisi lingkungan daripada keberadaan T. castaneum. Sebanyak 19 spesies cendawan telah diisolasi selama penyimpanan. Cendawan yang dominan ialah Aspergillus flavus dan Penicillium citrinum. Populasi total cendawan semakin menurun setelah 2 dan 3 bulan penyimpanan dengan bertambahnya jumlah pasangan T. castaneum yang diinfestasikan. Susut bobot semakin meningkat dengan bertambahnya jumlah pasangan T. castaneum yang diinfestasikan. Berdasarkan susut bobot beras, penyimpanan yang paling baik ialah pada jumlah pasangan T. castaneum adalah lima pasang, baik beras disimpan selama 1, 2, atau 3 bulan penyimpanan.Kata kunci: Aspergillus flavus, cendawan pascapanen, kadar air, Penicillium citrinum, susut bobot ABSTRACTTribolium castaneum is an important insect pest of stored milled rice in Indonesia. The effect of T. castaneum on fungal infection of stored milled rice was investigated together with moisture content and weight loss. Milled rice were placed in glass jars (250 g/jar) and infested with 5, 10, and 20 pairs of T. castaneum. As control, the jars contained only milled rice. Three replications were made for each treatment (including the control). The jars were stored in storage room for 1, 2, and 3 months. Moisture contents (based on wet weight) of milled rice were determined using the oven method. Fungi were isolated and enumerated using dilution plating, followed by pour plate method on Dichloran 18% Glycerol Agar (DG18). Weight loss (based on dry weight) was determined after 3 months of storage.The results *Alamat penulis korespondensi:

The aim of this investigation was to determine the effect of various water activities (a w ) on fungal population in nutmeg kernels during storage. The seed nutmegs were obtained from ripe fruits one week after they fell on the ground in North Minahasa Regency, North Sulawesi Province, Indonesia. The kernels (moisture content ± 10%) were stored 0, 15, and 30 days in various a w (0.75, 0.80, 0.83, 0.90, 0.97) using saturated salt solutions at 29 °C in sorption containers. Serial dilution method followed by a pour-plate method in Dichloran 18% Glycerol Agar (DG18) was used to isolate and quantify the fungal population. Results revealed that kernels stored at a w p < 0.05) different from at a w = 0.80-0.83. Fungal population of kernels determined a w p by duration of storage. Range of a w 0.80-0.83 has a smaller total fungal population than a w Aspergillus and Eurotium (6 species), Penicillium (3 species), Fusarium (2 species), 1 species each of Cladosporium or Syncephalastrum, and isolate A. The largest total fungal population (5.0×10 5 CFU g -1 ) was present at the beginning of storage (a w = 0.97) and it was dominated by Penicillium citrinum (2.6×10 5 CFU g -1 ) followed by Cladosporium cladosporioides (1.7×10 5 CFU g -1 ). After 30 days of storage (a w = 0.97) the population of P. citrinum was still dominant with a population of 2.4×10 4 CFU g -1 . Eurotium chevalieri followed with a population of 1.2×10 4 CFU g -1 .