ABSTRACT
The calorific value of post-fermentation biogas is a way down below standard and quite low due to the presence of high amount level of carbon dioxide (CO2) biogas mixture. Therefore, it raises the need to process the biogas, separating it from CO2 in order to obtain high-purity biogas as well as to maximize its calorific value. One widely available material that can be used as a sustainable carbon capture adsorbent is silica extracted from bamboo leaves. However, so that silica can act as CO2 adsorber, it is necessary to modify the surface of silica with CTAB and APTES (3-aminopropyl triethoxysilane). In this study, 2-stage method was carried out, namely preparation of mesoporous silica and surface modification using APTES on the mesoporous silica. Experiments in synthesizing APTES-modified silica were obtained by varying its composition: CTAB (1.5-5%w), (HCl 1.5-5 N), and APTES (10-30%). A central composite design (CCD) was employed in exploring the interaction between all variables and also performed for the optimization. Through analysis of variance, it shows that optimum CO2 adsorption capacity reaches 47.02 mg g-1, by applying 4.98% of CTAB, 4.28 N of HCl and 10.08% of APTES. Pseudo-second-order kinetic and Redlich-Peterson isotherm models are more representative to show the adsorption behavior of CO2 into the modified silica. The results show that the modified silica with APTES shows a prospective application of silica for CO2 removal from biogas.
Subject(s)
Biofuels , Propylamines , Silanes , Silicon Dioxide , Cetrimonium , Carbon DioxideABSTRACT
Due to high rice consumption, food insecurity can negatively impact health; hence, food diversification is considered an appropriate solution for achieving national food security. Artificial rice production using local natural resources will support food sustainability in Indonesia. Sago, arrowroot tuber, and mung bean flours were the main ingredients for producing artificial rice using the hot extrusion method. The effects of composite flour composition and extrusion temperatures on the nutritional value (carbohydrate, protein, fat, and fiber), morphological structure (scanning electron microscopy analysis), thermal stability (differential scanning calorimetry analysis), and acceptability of artificial rice were investigated in this study. The results showed that the best composition was obtained when using a combination of 50% (w/w) sago flour, 30% (w/w) arrowroot tuber flour, and 20% (w/w) mung bean flour. The results of chemical analysis showed that the best artificial rice in this study contained 11.18% water content, 80.27% carbohydrates, 5.14% protein, 0.46% fat, and 5.14% crude fiber. The product contained sufficient fiber and carbohydrate content to be an appropriate staple food. The best extrusion temperature was 85 °C. Moreover, the differential scanning calorimetry profiles showed that artificial rice began undergoing physical changes at approximately 100 °C. Importantly, the color, texture, aroma, and taste of the cooked artificial rice were accepted by consumers.
ABSTRACT
Extrusion technology allows the preparation of analog rice, an artificial product made of carbohydrate sources other than rice, with characteristics similar to natural rice. In this study, we aimed at determining the effect of composition and temperature on the nutritional content of analog rice obtained using heat extrusion technology. The physical properties and acceptability of the resulting product were also studied. Skim milk, sago, mung bean, and corn flour as well as the binder carboxymethyl cellulose (CMC) were used. The procedure was conducted in four stages: raw-material preparation, formulation, physicochemical evaluation, and sensory property evaluation. The best analog rice formula was established as 50% sago flour, 30% corn flour, 19.2% mung bean flour, 0.4% skim milk, and 0.4% CMC. The panelists' most preferred rice analog formula was the one with the highest sago starch and skim milk content. The extrusion temperature did not significantly affect the nutrient content. However, it had a considerable impact on the thermal profile and physical properties, such as appearance and granular morphology.
ABSTRACT
This study was conducted to determine the effect of composite flour (CF) constituents and different extrusion temperatures on the production of analog rice and community perceptions about the produced rice. CF was produced by mixing modified cassava flour (Mocaf) and snakehead fish flour (SF) in the following ratios: 100:0; 97:3; 94:6; 91:9; and 88:12. Analog rice was then extruded from CF at the following temperatures: 50, 70, and 90°C. The analog rice was tested for physical properties (bulk density and cooking time), chemical properties (nutrient content), and organoleptic properties. The results showed that CF and extrusion temperature affect the nutrient content of analog rice. The best analog rice formulation constituted of CF with Mocaf:SF ratio of 91:9 and extrusion temperature of 70°C, and contained 14.34% water, 0.85% ash, 71.83% carbohydrate, 11.24% protein, 1.12%, calcium 1,113 ppm, and 2.43% dietary fiber. This study included 42 respondents aged 20-23 years, including 20 males and 22 females. All the respondents showed acceptance for the analog rice, suggesting that it could substitute ordinary rice as a staple food.
ABSTRACT
The disadvantageous properties of sago starch has limited its application in food and industrial processes. The properties of sago starch can be improved by changing its physicochemical and rheological characteristics. This study examined the influence of reaction time, acidity, and starch concentration on the oxidation of sago starch with ozone, a strong oxidant. Swelling, solubility, carbonyl, carboxyl, granule morphology, thermal profile, and functional groups are comprehensively observed parameters. With starch concentrations of 10-30% (v/w) and more prolonged oxidation, sago starch was most soluble at pH 10. The swelling power decreased with a longer reaction time, reaching the lowest pH 10. In contrast, the carbonyl and carboxyl content exhibited the same pattern as solubility. A more alkaline environment tended to create modified starch with more favorable properties. Over time, oxidation shows more significant characteristics, indicating a superb product of this reaction. At the starch concentration of 20%, modified sago starch with the most favorable properties was created. When compared to modified starch, native starch is generally shaped in a more oval and irregular manner. Additionally, native starch and modified starch had similar spectral patterns and identical X-ray diffraction patterns. Meanwhile, oxidized starch had different gelatinization and retrogradation temperatures to those of the native starch.
ABSTRACT
The biogas fermentation of vinasse (TS 7.015 ± 0.007%) was investigated within a wide range of COD (Chemical Oxygen Demand)/N (Total Nitrogen) ratio. Urea (46% nitrogen content) was added into substrate to adjust COD/N ratio of 400/7-700/7. This study used batch anaerobic digesters in laboratory-scale that were operated at room temperature in 60 days. The results showed that control variable, 400/7, 500/7, 600/7, 700/7 generated total biogas of 107.45, 123.87, 133.82, 139.17, 113.27 mL/g COD and had the value of COD removal of 31.274 ± 0.887, 33.483 ± 0.266, 36.573 ± 1.689, 38.088 ± 0.872, 32.714 ± 0.881%, respectively. Variable with COD/N ratio of 600/7 was the best variable. In the kinetic model of biogas production, variable with COD/N of 600/7 had kinetic constant of A (mL/g COD), µ (mL/g COD.day), λ (days) of 132.580, 15.200, 0.213, respectively. The model equation of kinetic of biodegradability organic materials obtained was [formula in text].