ANALISIS EKSTRAK TUMBUHAN REMPAH SEBAGAI PRESERVATIVES MAKANAN TAHU DIUJI SECARA IN VITRO
Authors: Widiyanti Ni Luh putu manik , Mulyadiharja Sanusi , Sukarta I Nyoman 
Published: January 2017

AbstrakMakanan tahu merupakan makanan tradisional dan sebagai sumber protein yang bermutu tinggi yang banyak mengandung asam amino esensial dan terbukti menurunkan kadar Low Density Lipoprotein. Tahu mudah mengalami pembusukan oleh bakteri, karena kadar protein dan kadar air yang tinggi. Tetapi banyak pengusaha nakal dengan menambahkan formalin dan pewarna methyl yellow yang dilarang penggunaaanya dalam makanan menurut peraturan Menkes Nomor 1168/Menkes/PER/X/1999 untuk pengawet makanan tahu. Alternatifnya adalah tanaman rempah sebagai antibakteri dan dimanfaatkan sebagai bahan pengawet alami makanan antara lain tanaman Cymbopogon ciratus (sereh), Cucurma domestika (kunyit) dan Alpinia galanga (lengkuas) untuk menghambat pertumbuhan bakteri pada makanan tahu. Tahu yang berhasil dibuat masih belum memenuhi standar penilaian SNI 01-3142-1992 yaitu pada bagian rasa, yaitu sebanyak 50% panelis yang menyatakan rasa tahu sedikit asam. Uji organoleptik makanan tahu pada hari pertama perendaman dengan preservatives alami, sebanyak 100% panelis menyatakan tahu yang direndam dengan ke-3 preservative alami beraroma dan berrasa harum preservatives alami (sereh, kunyit dan lengkuas). Karakteristik warna tahu, 100% panelis menyatakan putih bersih atau kekuningan bersih dan 100% panelis menyatakan penampakkan normal tidak berlendir dan berjamur. Terjadi penurunan kualitas tahu dari uji organoleptik pada hari ke-tiga dan ke-enam baik pada aroma, rasa, warna dan penampakan tahu. Gain Score menunjukkan bahwa tahu yang direndam dengan preservative alami sereh konsentrasi 20% yang menunjukkan peningkatan jumlah bakteri. Pada hari ke-3 dan ke-6, tahu yang direndam dengan konsentrasi 40% dan 60% menghambat pertumbuhan bakteri. Hasil Gain Score pada makanan tahu yang direndam dengan preservatives alami kunyit pada hari ke-1 dan ke-6 dengan konsentrasi 20%, 40% dan 60 % menunjukkan preservative kunyit pada semua konsentrasi tidak menghambat pertumbuhan bakteri yang hidup pada makanan tahu. Pada hari ke-3, hanya tahu yang direndam dengan konsentrasi 60% yang menghambat pertumbuhan bakteri. Gain Score menunjukkan makanan tahu yang direndam dengan preservatives alami lengkuas pada hari ke-1 hanya konsentrasi 40% yang menunjukkan penghambatan jumlah bakteri. Pada hari ke-3 dan ke-6, tidak ada konsentrasi preservatives lengkuas menghambat pertumbuhan bakteri. Jumlah SPC bakteri yang direndam dengan preservative sereh konsentrasi 40% berbeda bermakna dengan preservatives kunyit konsentrasi 20% dan lengkuas 20%. Jumlah SPC bakteri yang direndam dengan preservatives sereh konsentrasi 60% berbeda bermakna dengan preservatives kunyit konsentrasi 20%, lengkuas 20% dan lengkuas 40%. Jumlah SPC bakteri yang direndam dengan preservatives kunyit 20% berbeda bermakna dengan preservatives sereh 40% dan sereh 60%. Jumlah SPC bakteri yang direndam dengan preservative lengkuas 20% berbeda bermakna dengan preservatives sereh 40% dan sereh 60%. Jumlah SPC bakteri yang direndam dengan preservatives lengkuas 40% berbeda bermakna dengan preservatives sereh 60% dengan p<0,05. Zona hambatan oleh sereh konsentrasi 20% dan 40% berbeda bermakna dibandingkan dengan zona hambatan oleh kunyit 60% dan lengkuas 60% terhadap pertumbuhan bakteri. Zona hambatan oleh sereh konsentrasi 60% berbeda bermakna dibandingkan dengan zona hambatan oleh ketiga preservatives konsentrasi 20% dan 40% terhadap pertumbuhan bakteri. Zona hambatan oleh kunyit konsentrasi 20% berbeda bermakna dibandingkan dengan zona hambatan oleh ketiga preservatives konsentrasi 60% terhadap pertumbuhan bakteri. Zona hambatan oleh kunyit konsentrasi 40% berbeda bermakna dibandingkan dengan zona hambatan oleh ketiga preservatives konsentrasi 60% terhadap pertumbuhan bakteri. Zona hambatan oleh kunyit konsentrasi 60% berbeda bermakna dibandingkan dengan zona hambatan oleh ketiga preservatives konsentrasi 20% dan 40% terhadap pertumbuhan bakteri. Zona hambatan oleh lengkuas konsentrasi 20% dan 40% berbeda bermakna dibandingkan ketiga preservatives konsentrasi 60% terhadap pertumbuhan bakteri. Zona hambatan oleh lengkuas konsentrasi 60% berbeda bermakna dibandingkan dengan zona hambatan oleh ketiga preservatives konsentrasi 20% dan 40% terhadap pertumbuhan bakteri. Adanya zona hambatan disebabkan karena bahan aktif yang terdapat pada ketiga preservatives. Uji koefisien phenol menunjukkan bahwa ke- 3 preservatives alami yang diekstrak dengan hidrodestilasi dengan nilai sama atau kurang efektif dibandingkan phenol. Kata kunci : tanaman rempah, pengawet alami, makanan tahu, uji in vitro AbstractTofu is know as a traditional food and as a source of high quality protein that contains many essential amino acids and is proven to reduce levels of Low Density Lipoprotein. Tofu susceptible to decomposition by bacteria, because high of the protein content and water content. But many food entrepreneurs that naughty by adding formalin and methanyl yellow dye that banned its use in food regulation by Minister of Health Num. 1168/Menkes/PER/X/1999 for the food preservatives of tofu. The alternative is an antibacterial plants and used as a natural food preservatives including Cymbopogan ciratus (lemongrass), Cucurma domestica (turmeric) and Alpinia galanga (galangal) to inhibit bacterial growth in tofu. Tofu that has been created is still not meet the assessment standards of SNI 01-3142-1992 in aroma part, whereas 50% panelists who stated aroma tofu is slightly acidic. Organoleptic test of tofu in first day of soaked with natural preservatives, 100% panelists who stated tofu that soaked with three kinds natural preservatives with aroma and taste of Cymbopogon ciratus (lemongrass), Cucurma domestica (turmeric) and Alpinia galanga (galangal) extracts. The characteristic color of tofu, 100% panelists expressed that tofu with pure white color or pure yellowish and 100% panelists who stated normal of tofu in performance without slimy and moldy. In fact characteristic of tofu is decrease of quality result from organoleptic test on day three and six both in aroma, taste, color and performance of tofu. Gain score result show that tofu soaked with natural preservatives lemongrass concentration 20% that show increase bacteria in number. On third and six days, tofu soaked with 40% and 60% concentrations of lemongrass inhibit growth of bacteria. Result gain score indicates tofu that soaked with tumeric extract on first and sixth days soaked with 20%, 40% and 60% concentrations show all of tumeric extract concentrations didnt inhibit growth of bacteria. On the third day tofu that soaked with only 60% concentration capable to inhibit growth of bacteria. Result gain score indicates tofu that soaked with extract of galangal in first day, only concentration 40% show inhibit growth of bacteria. On third and sixth days, all of concentrations of galangal extract didnt capable inhibit growth of bacteria. Number of SPC bacteria in tofu soaked with preservatives lemongrass with concentration 40% was significantly different with tofu that soaked extract of 20% concentrations of turmeric and galangal. Number of SPC bacteria in tofu soaked with lemongrass concentration 60% was significantly different with 20% concentrations of both turmeric and galangal, and 40% concentration of galangal. Number SPC of bacteria in tofu soaked with 20% concentration of turmeric was significantly different with 40% and 60% concentrations of lemongrass. Number SPC of bacteria in tofu soaked with 20% concentration of galangal, was significantly different with 40% and 60% concentrations of lemongrass. Number SPC of bacteria in tofu soaked with 40% concentration of galangal was significantly different with 60% concentration of preservatives lemongrass with p<0,05. Inhibition zone by 20% and 40% concentration of lemongrass was significantly different compared with inhibition zone by both 60% concentrations of turmeric and galangal toward growth of bacteria. Inhibition zone by 60% concentration of lemongrass was significantly different compared with inhibition zone by three kinds of preservatives in 20% and 40% concentrations toward growth of bacteria. Inhibition zona by 20% concentration of tumeric was significantly different compared with inhibition zone by three kinds of preservatives in 60% concentration toward growth of bacteria. Inhibition zone by 40% concentration of tumeric was significantly different compared with inhibition zone by three kinds of preservatives in 60% concentration toward growth of bacteria. Inhibition zone by 60% concentration of tumeric was significantly different compared with inhibition zone by three kinds of preservatives in 20% and 40% concentrations toward growth of bacteria. Inhibition zone by 20% and 40% concentrations of galangal was significantly different compared with inhibition zone by three kinds of preservatives in 60% concentration toward growth of bacteria. Inhibition zone by 60% concentration of galangal was significantly different compared with inhibition zone by three kinds of preservatives in 20% and 40% concentrations toward growth of bacteria. Inhibiton zone was present in growth of bacteria caused by active substances in three kinds of natural preservatives. Coeffisient phenol test was done that show three kinds of natural preservatives was extracted by hydrodestillation with value equal or less effective than pure phenol. Key words : spices plants, natural preservatives, tofu, in vitro test.