ABSTRAKYogurt merupakan salah satu produk pangan fungsional yang mengandung bakteri probiotik untuk memperbaiki keseimbangan mikroflora usus. Nilai fungsional yogurt dapat ditingkatkan dengan penambahan tepung talas termodifikasi untuk menstimulasi pertumbuhan bakteri probiotik dalam saluran pencernaan. Penelitian ini bertujuan untuk mengetahui pengaruh variasi starter bakteri asam laktat dan penambahan tepung talas termodifikasi terhadap kualitas yogurt talas sinbiotik. Metode penelitian ini menggunakan rancangan acak kelompok. Parameter yang diamati pada penelitian ini adalah nilai pH, total asam tertitrasi, viabilitas bakteri asam laktat dan uji organoleptik. Hasil penelitian menunjukan bahwa variasi starter terbaik adalah yogurt yang dibuat dari Lactobacillus bulgaricus + Lactobacillus achidophillus + Streptococcus thermophillus dengan nilai pH 4, total asam tertitrasi 1,32%, total bakteri asam laktat 6,93 log cfu/ml, dan total uji organoleptik dengan nilai 4,5. Sementara itu penambahan tepung talas termodifikasi (TTM) terbaik untuk produksi yogurt talas sinbiotik adalah sebesar 0,5% (b/v) dengan nilai pH 4,5, total asam tertitrasi 1,44%, total bakteri asam laktat (BAL) 7,01 log cfu/ml, dan total uji organoleptik 4,215. Perlakuan variasi starter kultur bakteri asam laktat dan penambahan tepung talas termodifikasi tidak memberikan pengaruh yang signifikan terhadap perubahan nilai pH, kadar total asam tertitrasi dan kualitas organoleptik (rasa, tekstur, warna, aroma) dari yogurt sinbiotik. Secara mikrobiologis dan organoleptik kualitas produk yogurt talas simbiotik tetap terjaga selama masa penyimpanan 4 minggu pada suhu dingin.Kata Kunci: Kualitas produk, starter bakteri asam laktat, tepung talas prebiotik, yogurt talas sinbiotik ABSTRACTYogurt was the one of functional food product which contains probiotic bacteria to improve the balance of intestinal microflora. The functional value of yogurt can be increased by the addition of modified taro flour to stimulate the growth of probiotic bacteria in the digestive tract. This study aimed to determine the effect of variation lactic acid bacteria starter and fortified of modified taro flour for the quality of taro yogurt synbiotic. This research used statistical randomized block design. The parameters which used to determine the quality of yogurt in this study were pH value, total acid content, the viability of lactic acid bacteria and organoleptic tests. The results showed that the best combination starter to produce yogurt were starter Lactobacillus bulgaricus + Lactobacillus achidophillus + Streptococcus thermophillus with a pH value of 4, total acid content 1.32%, total lactic acid bacteria 6.93 log cfu / ml, and total organoleptic test by a value of 4.5. Meanwhile, the best formulation was added to modify taro flour (TTM) 0.5 % (w/v) to produce taro yogurt synbiotic with pH value 4.5, total acid content 1.44%, total lactic acid bacteria (LAB) 7.01 log cfu / ml, and total organoleptic test 4.215. Variation of lactic acid bacteria starter and fortification of m...

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This study investigated the effects of annealing, autoclaving-cooling and heat moisture treatment on the microstructure and physicochemical characteristics of taro starch. The taro starch was treated by the annealing process (24 hrs, 50 o C), the heat moisture treatment (HMT) (moisture 25%, 3 hrs, 110 o C), and the autoclaving (15 mins, 121 o C)cooling (24 hrs, 4 o C) with 1 and 2 cycles. The results show that the autoclaving-cooling 2 cycles (AC-2C) changed the microstructure of taro starch into a very compact and dense structure because of formed double helix bound that cannot be hydrolyzed by pancreatic enzymes so it can be converted became resistant starch as the prebiotic source. Pasting properties analysis showed that AC-2C improved shear stress resistance, heat resistance and low retrogradation modified taro starch (MTS). The AC-2C treatment increased water binding capacity (73.84%), solubility (44.58%), and swelling power (16.71%) of MTS. The water-binding capacity had a positive correlation with solubility and swelling power. The AC-2C treatment increased amylose content (27.40%) and decreased reducing sugar level (6.36%) of MTS, so it can encourage the formation of resistant starch to improve the prebiotic properties of taro starch. Modified taro starch AC-2C is the best compared to HMT and annealing based on microstructure and physicochemical characteristics.

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The aim of the research was to find the partial purified of enzyme protease from Bacillus sp. The crude enzyme of protease was produce in rice brand medium (100 gram of rice brand in a liter tofu liquid waste). The enzyme was semi-purified by the procedure of precipitation using ethanol in different percentages of saturation, gel filtration using Sephadex G 100 and Ion Exchanged Chromatography using DEAE Sephadex A50. Specific activities of the enzyme during purification were 5.71 U/mg (crude enzyme); 6.75 U/mg (ethanol precipitations); 37.16 U/mg (gel filtration) and 43.02 U/mg (Ion Exchanged Chromatography). The optimum temperature for enzyme reaction was 45–50 °C, while the optimum pH was 7.0–8.0. Protease was relatively stable after heating until 37–50 °C for 60 minutes. Metal ions had different effects to the enzyme. CaCl2, FeCl3, MnCl2, ZnCl2 and MgCl2 increased enzyme activity, CdCl2 and HgCl2 gave an inhibitory effect, and another of metal ions had no effects to the enzyme.