Optimalisasi fermentasi rhizopus oryzae dalam pembentukan curd dan analisis kualitas keju mentah yang terbentuk

Oleh :
Makhabbah Jamilatun - S900908008 -

Rhizopus oryzae yang dikenal sebagai jamur tempe, merupakan jamur yang berpotensi dalam pembuatan keju. R.oryzae diketahui mampu menghasilkan asam laktat, protease, dan lipase. Asam laktat akan membantu mengasamkan susu, protease berfungsi memecah kasein susu serta lipase berfungsi sebagai pemecah lemak yang akan meningkatkan flavor keju. Akan tetapi hingga saat ini, belum didapatkan informasi mengenai penggunaan R.oryzae untuk fermentasi susu dalam pembuatan keju. Pada penelitian ini dilakukan optimalisasi fermentasi oleh R.oryzae yang meliputi variasi konsentrasi inokulum (10%; 15%; 20%), suhu (370C; 400C), dan waktu (6jam; 9jam) fermentasi susu dalam pembentukan curd. Terdapat tiga tahapan penelitian. Pertama, penghitungan laju pertumbuhan R.oryzae dan pengukuran nilai pH pada starter dan selama fermentasi dalam pembentukan curd. Kedua, pembuatan keju yang dilanjutkan dengan analisis kualitas fisik, kimia, dan uji kesukaan. Ketiga, uji kualitas mikrobiologi serta analisis profil delapan asam amino esensial pada keju mentah yang terbentuk pada kondisi optimum fermentasi. Hasil penelitian menunjukkan bahwa keju mentah yang disukai panelis adalah keju mentah yang terbentuk pada kondisi optimum fermentasi formula perlakuan 20%, 370C, 9 jam. Perbedaan kondisi fermentasi berpengaruh terhadap rendemen curd, nilai pH, kadar lemak, dan tidak berpengaruh terhadap kadar air, kadar protein keju mentah yang terbentuk. Keju mentah yang terbentuk pada kondisi optimum memiliki jumlah rendemen curd 10,76%, kadar air 47,23%, nilai pH 5,56, kadar lemak 40,70%, dan kadar protein terlarut 2,23%. Jumlah total mikroba sebanyak 8,1x106, bakteri sebanyak 3,7x106 dan kapang sebanyak 1,2x106. Hasil identifikasi mikroba meliputi Enterococcus hirae (Enterococcus faecalis), Bacillus subtilis, dan Aspergillus sp. Analisa profil delapan asam amino esensial meliputi: L-Threonine (1,15 ppm), L-Methionine (0,47 ppm), L-Valine + L-Thriptophan (0,70ppm), L-Phenylalanine (0,66ppm), L-Isoleucine (0,48ppm), L-Leucine (1,28ppm), L-Lycine (1,64 ppm). Kata kunci: Rhizopus oryzae, fermentasi, curd, keju mentah. Rhizopus oryzae known as tempe fungus, is a potential fungus in producing cheese. R.oryzae is able to produce lactic acid, protease and lipase. Lactic acid will help acidifying the milk, while protease and lipase are enzymes that help in splitting the milk’s casein fat subsequently that will improve the cheese flavor. However, up to now there was not any information about the use of R.oryzae for the milk fermentation in the cheese preparation. In this research the fermentation optimization was conducted by R.oryzae involving the concentration variation of inoculum (10%; 15%; 20%), variation of temperature (37oC; 40oC), and time (6 hours; 9 hours) of the milk fermentation in the curd formation. The procedure of research consisted of three steps. The first was calculating R.oryzae’s growth rate and pH value measurement on starter and during the fermentation in curd formation. The second was the cheese preparation followed by the analysis on physical, chemical qualities and preference test. The third was analysis on microbiology quality test as well as the essential amino acid profile of the unripened cheese created in the optimum fermentation condition. The result of the research indicated that the unripened cheese preferred by the panelist was the unripened cheese created in optimum fermentation condition with formula 20%, 37oC, 9 hours. The difference of fermentation condition affects significantly the curd content, pH value, fat level, and does not affect the water, and dissolved protein levels. Unripened cheese that created in optimum fermentation condition has the curd content of 10.76%; water level was 47.23%; pH value was 5.56; fat level was 40.70%; the dissolved protein level was 2.23%; total microbe number was 8,1x106 cfu ml-1, bacteria was 3,7x106 and fungi was 1,2x106. The result of microbial identification included Enterococcus hirae (Enterococcus faecalis) and Bacillus subtilis, and Aspergillus sp. The analysis on essential amino acid profile included L-Threonine (1,15 ppm), L-Methionine (0,47 ppm), L-Valine + L-Thriptophan (0,70 ppm), L-Phenylalanine (0,66 ppm), L-Isoleucine (0,48 ppm), L-Leucine (1,28 ppm), L-Lycine (1,64 ppm). Keywords: Rhizopus oryzae, fermentation, curd, unripened cheese