Indah Yuliasih

Acid Modification of Sago Hampas for Industrial Purposes

Sago pith and sago hampas mainly consist of starch and fiber. In this research, acid modification of starch and fiber was conducted by high-temperature (autoclaving) and microwave-assisted treatments and slow or mild acid hydrolysis. Autoclaving and microwave-assisted treatments influenced the gelatinization and solubilization of starch granules to produce depolymerized starch and changed the fiber structure to become more amorphous forms. Heating in dilute acid produced high soluble total sugars with high dextrose equivalent, but the process also released hydroxymethylfurfural as undesired by-products. Slow or mild acid hydrolysis attacked the amorphous regions of starch and fiber. It did not change the starch and fiber crystallinity pattern but increased the degree of crystallinity. Acid modification techniques for sago starch and its fiber can be used for producing certain products such as starch sugar, fermentable sugars, and filler for biofoam production.

PENGARUH EDIBLE COATING TERHADAP KAPASITAS AIR TERIKAT SEKUNDER DAN TERSIER MANISAN TOMAT CHERRY SELAMA PENYIMPANAN

The use of an antimicrobial edible coating is a technique that can be developed and applied to keep the quality and extend the shelf life of products, such as candied cherry tomato. This study purposed to get processing technology candied cherry tomatoes, to formulate edible coating with cinnamon oil as an antimicrobial, and to analyse the effect of edible coating to changes in the quality of candied cherry tomatoes during the storage process. The stages of this research were the production process of candied cherry tomatoes, which consisted of determining treatment cherry tomatoesas a whole and sliced cross, a combination of sugar concentration and immersion time in a sugar solution, and determination of drying time candied cherry tomatoes. The next steps were manufacturing and characterization of antimicrobial edible coating, and then application of antimicrobial edible coating during 12 weeks of storage. Based on the results, the best treatment processing of candied cherry tomatoes was a cherry tomato with an intact form and had 40-55-70% graded sugar concentration during 12 hours immersion time, and at 33 hours drying time. Moreover, resulted fromedible coating formula was tapioca starch, CMC, glycerol, stearic acid and cinnamon oil with percentages of 3.0%, 0.4%, 5.0%, 0.5%, and 0.6%, respectively. During storage, lowest secondary and tertiary bound water capacity on candied cherry tomatoes with an antimicrobial edible coating that was Ms of 25.32%, awsof 0.58 and Mt of 42.11%. Likewise, the lowest rate of microbial growth was from candied cherry tomatoes with an antimicrobial edible coating. Keywords: antimicrobial, bound water capacity, candied cherry tomato, cinnamon oil, edible coatingPartial oxidation pretreatment on sorghum straw using a consortium of microorganisms EM4 was done before used as raw material for production of biogas. Biogas production was performed by co-digestion method using sludge of waste water treatment plant. This research aimed to study the effect of sorghum straw and sludge ratio to the production of biogas by co-digestion method. Partial hydrolysis pretreatment using concentrations of EM4 0.0, 0.1, 0.5, and 1.0%. Pretreatment parameter measured was chemical oxygen demand dissolved (COD). The result of sorghum straw pretreatment was used as raw material for biogas production. Co-digestion method of sorghum straw and sludge was carried out by ratio variation of 80:20, 75:25, 70:30, and 65:35 (w/w). Parameters measured were cumulative biogas production (L/kg VS) and the composition of the biogas (CH4 and CO2). Results of partial oxidation pretreatment showed that the higher concentration of EM4 affected in higher levels of dissolved COD. Biogas production results by this pretreatment showed that the higher concentrations of EM4, the shorter adaptation phase of anaerobic microorganisms and higher production of biogas. The highest biogas production by co-digestion method was 371 L/kgVS, achieved by ratio of sorghum straw to sludge of 75:25 (w/w) in 65 days of fermentation. By using co-digestion method, biogas production increased 245-293%. From the results of this research note that biogas production on a pilot scale 25 L was lower than Erlenmeyer digester 0.5 L.Composition of biogas consisted of CH4 : CO2 76:26 and biogas was flammable. Keywords: sorghum straw, EM4, sludge, co-digestion, biogasCurrent technology for biodiesel production is a transesterification process of vegetable oil with metanol in batch system with the help of catalyst. The technology faces many disadvantageous for large scale, such as the requirement for rigorous stirring and purification of the product from the catalyst. Previous study showed that utilization of static mixing reactor can enhance the reaction rate and reduce the requirement of catalyst and can be operated continuously. The objective of this study was to examine the role of static mixer in reducing the catalyst requirement for the transesterification process of biodiesel production in continuous mode. Palm oleinwas used as feedstock for the transesterification process with 1:6 of mole ratio to metanol at 65oC reaction temperature. Catalyst used for the experiment was KOH with variations of 0.3% and 0.5% to the oil fed into the reactor and the numbers of static mixer modules were varied (1, 2, 3, 4, and 5 modules) to evaluate their effects to the required catalyst. As expected, the experimental results confirmed a higher conversion of the reactionby the increasing number of the static mixer modules at a specific catalyst percentage. Highest conversions obtained with 5 moduleswere 92.5% (w/w) and 88.9% (w/w), for 0.3% and 0.5% of catalyst, respectively. Analysis to the experimental results showed that 0.1% of catalyst could be replaced by the addition of 0.9 modules of static mixer, which was equivalent to 58.1 cm length ofthe used static mixer configuration. Keywords:continuous mode of transesterification, static mixing module, catalyst reduction

Effect of Corn Hominy and Polyvinyl Alcohol on Mechanical Properties of Cassava Starch-Baked Foam

Agromaterials such as starch and fiber are very promising raw materials to reduce our dependence on polystyrene. Corn hominy, a by-product of the corn milling industry, is a potential source to reinforce starch-baked foam. The effects of corn hominy and PVOH addition on mechanical properties of Cassava starch foam were investigated. Different formulations of Cassava starch, corn hominy and PVOH were mixed with liquid to get total solids at 50% and baked in a thermopressing machine at 150–170°C for 2 min. The results showed that corn hominy and PVOH addition can improve compressibility and tensile strength of the foams but gave denser foam and darker color. Ratio of tapioca: corn hominy: PVOH = (75:25):30% gave the best foam properties. GRAPHICAL ABSTRACT