Kemampuan Rhizopus oligosporus untuk menurunkan cemaran AFB1

WIPRADNYADEWI, Putu Ari Sandhi, Dr.Ir. Endang S. Rahayu, MS

2005 | Tesis | S2 Ilmu dan Teknologi Pangan

Aflatoksin B1 adalah metabolit sekunder berpotensi toksik, karsinogenik, teratogen, dan mutagen yang diproduksi oleh Aspergillus flavus dan A.parasiticus. Cemaran AFB1 terdapat pada komoditi kacang tanah, jagung, kedele dan produk olahannya. Tempe adalah produk makanan tradisional khas Indonesia hasil fermentasi kedele oleh jamur R. oligosporus. Dalam penelitian ini diuji kemampuan strain Rhizopus hasil isolasi beberapa inokulum tempe untuk menurunkan cemaran AFB1 dan penerapannya pada proses fermentasi tempe. Ada 3 tahap utama dalam penelitian ini yaitu : (1) Isolasi jamur yang tumbuh pada 7 sampel inokulum tempe, (2) Uji kemampuan strain R. oligosporus hasil isolasi dari beberapa inokulum tempe untuk menurunkan cemaran AFB1 dalam media cair sintetik, (3) Penerapan strain R. oligosporus terpilih untuk proses fermentasi tempe. Diamati juga berat miselia kering strain Rhizopus dan penurunan cemaran AFB1 selama pertumbuhannya dalam media cair sintetik. Metode analisa AFB1 dilakukan dengan HPLC. Diperoleh 70 isolat terdiri dari 58 isolat berkonidia abu-abu kecoklatan, dan 12 isolat berkonidia abu-abu yang semua termasuk genera Rhizopus . Kemudian dari 70 isolat dipilih 7 isolat dan 1 biakan murni R. oligosporus FNCC 6010 berdasarkan asal inokulum tempe, warna konidia, pertumbuhan miselia dan konidia. Berdasarkan pada hasil pengamatan makroskopik dan mikroskopik ke-7 isolat diatas termasuk dalam R. oligosporus. Isolat tersebut kemudian diuji kemampuannya menurunkan cemaran AFB1 dalam media cair sintetik berkisar antara 4,35 ppb sampai 81,13 ppb selama fermentasi 3 hari. Isolat R. oligosporus MK 1 memiliki laju pertumbuhan miselia pada fase logaritmik tertinggi dan berpotensi menurunkan cemaran AFB1 dalam media cair sintetik sehingga dipilih dalam proses fermentasi tempe serta menghasilkan tempe yang memiliki cemaran AFB1 rendah.

AFB1 is a secondary metabolite being a potent toxin, carcinogenic, teratogen, and mutagen produced by Aspergillus flavus and A. parasiticus. Peanut and their product are usually contaminated by AFB1. Tempe is a traditional fermented food of Indonesia made from soybean fermented by Rhizopus oligosporus. This research was concerning on the ability of strain Rhizopus isolated from several tempe inoculum in reducing AFB1 and during tempe fermentation. The research was carried out in 3 steps as followed: (1) Isolation of the fungi grown in seven several tempe inoculum samples, (2) Examinatin on an ability of strain R. oligosporus to reduce contaminant AFB1 in a synthetic broth, (3) Implementation of selected of strain R. oligosporus in tempe fermentation on process. Dry weight of each strain Rhizopus isolated was monitored reduction of contaminant AFB1 during their growth on a synthetic broth was calculated. The AFB1 analysis method was conducted by HPLC. Seventy microbes were isolated from tempe inoculum , consisted of 58 greyish brown conidia, and 12 grey conidia isolates. All isolates were belong to genera of Rhizopus. Seven of them were selected based an their origin of tempe inoculum, conidia colour, growth of mycelia, and conidia mass and 1 R. oligosporus FNCC 6010. Macroscopic and microscopic observation showed that the selected isolates were R. oligosporus. The isolates ability in reducing AFB1 was investigated by 3 days fermentation in synthetic broth medium with various concentration of AFB1 4,35 - 81,13 ppb. Isolate R. oligosporus MK 1 showed highest mycelia growth rate at logarithmic phase. R. oligosporus also decrease AFB1 in synthetic broth, so it was choosed in tempe fermentation to yield tempe with low concentration of AFB1.

Kata Kunci : Fermentasi Tempe,AFB1, fermentation, R. oligosporus, tempe, reduction of AFB1