Heri Purwoto - Academia.edu (original) (raw)

Papers by Heri Purwoto

IOP conference series. Earth and environmental science, Jun 1, 2024

Rasayan journal of chemistry/Rasayan journal of Chemistry, 2024

AIP conference proceedings, 2024

AIP conference proceedings, 2024

AIP conference proceedings, 2024

International Journal on Advanced Science, Engineering and Information Technology/International journal of advanced science, engineering and information technology, Apr 30, 2024

Journal of Chemical Engineering of Japan, 2003

Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose... more Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose and L-glutamic acid were added every 24 hours for 6 days to make the concentrations in the culture medium return to their initial values. We proposed a mixotrophic growth kinetics model to correlate a specific growth rate with a specific rate of energy consumption. In the model, the specific growth rate was proportional to the (1/n)th power of the specific energy consumption rate, and a corresponding yield parameter and a maintenance factor depended on light intensity. The specific growth rate in mixotrophic culture was correlated with incident light intensity by an equation that combined pseudo-photoautotrophic growth rate comparable to that of the modified Aiba model with heterotrophic growth rate. The optimum light intensity that produced the attainable maximum growth rate in mixotrophic culture could be estimated by the equation.

ASEAN Journal of Chemical Engineering

Carrageenan is a polysaccharide compound extracted from red seaweed and is widely used by food, c... more Carrageenan is a polysaccharide compound extracted from red seaweed and is widely used by food, cosmetic, and advanced materials industries because of its good properties as an environmentally friendly stabilizer. Carrageenan extraction generally uses alkaline treatment for one full day, where the treatment is to obtain carrageenan quality with good gel characteristics. The use of cellulase enzymes is thought to accelerate the desulfuration process of seaweed, where cellulase enzymes are used to break down cellulose in seaweed cell walls. By using a rapid visco analyzer (RVA), carrageenan was tested to see the pattern and viscosity value. This study aims to determine the effect of enzymatic pretreatment on the profile of carrageenan with a shorter alkalization process compared to the alkalization commonly used by the industry. The results showed that enzymatic treatment before KOH alkalization would produce a carrageenan profile with a viscosity value of 272-360 cP, whereas the NaOH...

This work introduces the modelling of absorption and scattering phenomena in the heterogeneous me... more This work introduces the modelling of absorption and scattering phenomena in the heterogeneous media of a photo-reactor and the prediction of the maximum fraction of light absorption that can be achieved. A new random walk model was proposed with two model parameters, cross sectional areas of absorption and scattering. The Monte Carlo approach was used for the simulation of the model. Isotropic and non-isotropic (forward, backward and side) scattering modes were considered. Any mode or any multiple combination of scattering can be set whenever one takes place. An absorption criterion was defined by comparing the model results with those of Schuster's infinite system. The model was verified experimentally and the agreement was satisfactory. For the experimental system, a heterogeneous medium was made using spherical silica particles and water, and was irradiated with parallel light beams from a laser light source. The model is capable of predicting light intensities and light abs...

Plastic packaging has dominated the waste, and the number is increasing every year. Candy plastic... more Plastic packaging has dominated the waste, and the number is increasing every year. Candy plastic packaging waste is most often considered trivial because of its small size, so it is usually disposed of carelessly. Due to its non-biodegradable, it causes environmental pollution. Edible film packaging is an alternative to reduce the impact of candy packaging waste pollution. The purpose of this study was to obtain the optimum formula of the edible film between corn starch, carrageenan, and rice bran as a hard candy packaging with the Response Surface Methodology (RSM) Central Surface Composite Design using the Design Expert 10.0.7. The prediction data obtained is then verified and tested by t-test at a 5% reliance interval.The optimum formulation of RSM results is 3.4% of corn starch, 1.1% of carrageenan and 0.38% of rice bran with predicted response of water content of 14.51%, WVTR 61,06 g/m/hour, viscosity of 258.8 cP, tensile strength of 107.9 kgf/cm, elongation of 19.41%, and mod...

This paper describes how Indonesia has been amongst the hardest hit in the current Asian economic... more This paper describes how Indonesia has been amongst the hardest hit in the current Asian economic crisis. Based on World Bank and IMF estimates, the short-term economic prospects are not encouraging. The Gross Domestic Product (GDP) was estimated to have declined by 15.6% in the 1998/99 financial year. The construction sector suffered the most (a 40% decline), financial services declined by 27% and the trade, hotel and restaurant sector declined by 21%. Only the agriculture and mining sectors have not been severely affected, although non-oil export earnings fell by 8.8%, notwithstanding severe depreciation of the Rupiah. In the face of ongoing financial sector problems, corporate dislocation and lower international commodity prices, positive economic growth is not expected for 1999/2000. Computable General Equilibrium (CGE) modeling is not a new quantitative approach in academic assessments, but in Indonesia it is relatively new undertaking in research community and its application ...

J Chem Eng Jpn, 2003

Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose... more Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose and L-glutamic acid were added every 24 hours for 6 days to make the concentrations in the culture medium return to their initial values. We proposed a mixotrophic growth kinetics model to correlate a specific growth rate with a specific rate of energy consumption. In the model, the specific growth rate was proportional to the (1/n)th power of the specific energy consumption rate, and a corresponding yield parameter and a maintenance factor depended on light intensity. The specific growth rate in mixotrophic culture was correlated with incident light intensity by an equation that combined pseudo-photoautotrophic growth rate comparable to that of the modified Aiba model with heterotrophic growth rate. The optimum light intensity that produced the attainable maximum growth rate in mixotrophic culture could be estimated by the equation.

Majalah Ilmiah Pengkajian Industri

Plastic packaging has dominated the waste and the number is increasing every year. Candy plastic ... more Plastic packaging has dominated the waste and the number is increasing every year. Candy plastic packaging waste is most often considered trivial because of its small size so it is usually disposed of carelessly. Every year the candy packaging waste contributes 0.3 billion. Due to its nonbiodegradable, it causes environmental pollution. Edible filmpackaging is an alternative to reduce the impact of candy packaging waste pollution.The purpose of this study was to obtain the optimum formula of edible film between based maize starch, carrageenan and rice bran as a hard candy packaging with the Response Surface Methodology (RSM) Central Surface Composite Design using the Design Expert 10.0.7. The prediction data obtained is then verified and tested by t-test at a 5% reliance interval.The optimum formulation of RSM results is 3,4% of maize starch, 1,1% of carrageenan and 0,38% of rice bran with predicted response of water content of 14,51%, WVTR 61,06 g/m2/hour, viscosity of 258,8 cP, te...

Industria: Jurnal Teknologi dan Manajemen Agroindustri

This research aimed to obtain the best formulation of corn starch, carrageenan, and rice bran as ... more This research aimed to obtain the best formulation of corn starch, carrageenan, and rice bran as the main components of edible film to improve formula’s viscosity, water content, and Water Vapour Transmission Rate (WVTR). This research was an experimental research using Randomized Complete Block Design (RCBD). The first factor was corn starch concentration (1.5%; 2.5%; 3.5%), the second factor was carrageenan concentration (0.67%; 1%; 1.33%), and the third factor was rice bran concentration (0.12%; 0.25%; 0.38%). The analysis of variance showed that the interaction of corn starch, carrageenan, and rice bran has a significant impact on the viscosity, water content, and WVTR value of the edible film. Based on the viscosity, water content, and WVTR value of the edible film, the best formulation was found in the edible film with the corn starch concentration of 2.5%, 1% carrageenan, and 0.25% rice bran. The formula's viscosity value of this edible film was 165.1 ± 5.3 cP, with 14.65...

Current Biochemistry

Capsules are very important in the packaging of pharmaceutical preparations. Commercial capsule s... more Capsules are very important in the packaging of pharmaceutical preparations. Commercial capsule shell is generally made of gelatin from cows and pigs. Alternatives to gelatin from non-animal raw materials can be obtained from polysaccharides like starch and carrageenan. The purpose of this study was to obtain the optimum formula between amylopectin and carrageenan as a raw material subtitute for gelatin capsule shell. Program Design Expert 7.0.0 (trial version) with Response Surface Methodology (RSM) Central Composite Design was used to optimize formula with three variable factors and three response variables. Based on the analysis by determining the adjusted range, program recommends 29 optimization solution with desirability value 1. Formula 6 and 28 was selected for validation with factors 1,01% of amylopectin, 1.01% of carrageenan, 2.17% of glycerin (formula 6) and 3.00% of amylopectin, 2.00% of carrageenan, 2.90% of glycerin (formula 28). Prediction response value was 12.94% of...

Majalah Ilmiah Pengkajian Industri

Penelitian ini dilakukan untuk mendapatkan formula optimum antara amilopektin pati singkong dan k... more Penelitian ini dilakukan untuk mendapatkan formula optimum antara amilopektin pati singkong dan karagenan sebagai bahan baku edible film. Program Design Expert 7.0.0 (trial version) dengan Response Surface Methodology (RSM) Central Composite Design (CCD) digunakan untuk mengoptimasi formula edible film. Variabel bebas yang digunakan yaitu persentase amilopektin, karagenan dan gliserin. Variabel respon yang diukur dan dioptimasi yaitu laju transmisi uap air, kuat tarik dan modulus elastisitas. Hasil optimasi dari program Design Expert 7.0.0 merekomendasikan 15 solusi optimasi dengan nilai desirability tertinggi sebesar 0.821. Formula satu dipilih untuk divalidasi dengan faktor-faktor yaitu amilopektin 3.00 %, karagenan 2.00 %, dan gliserin 2.00 %. Nilai respon prediksi untuk laju transmisi uap air sebesar 16.331 g/m2/24 jam, kuat tarik sebesar 180.657 kgf/cm2 dan modulus elastisitas sebesar 139.262 kgf/cm2. Nilai hasil validasi untuk laju transmis uap air sebesar 16.1027 g/m2/24 jam,...

Journal of Chemical Engineering of Japan, 2003

KAGAKU KOGAKU RONBUNSHU, 1999

IOP conference series. Earth and environmental science, Jun 1, 2024

Rasayan journal of chemistry/Rasayan journal of Chemistry, 2024

AIP conference proceedings, 2024

AIP conference proceedings, 2024

AIP conference proceedings, 2024

International Journal on Advanced Science, Engineering and Information Technology/International journal of advanced science, engineering and information technology, Apr 30, 2024

Journal of Chemical Engineering of Japan, 2003

Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose... more Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose and L-glutamic acid were added every 24 hours for 6 days to make the concentrations in the culture medium return to their initial values. We proposed a mixotrophic growth kinetics model to correlate a specific growth rate with a specific rate of energy consumption. In the model, the specific growth rate was proportional to the (1/n)th power of the specific energy consumption rate, and a corresponding yield parameter and a maintenance factor depended on light intensity. The specific growth rate in mixotrophic culture was correlated with incident light intensity by an equation that combined pseudo-photoautotrophic growth rate comparable to that of the modified Aiba model with heterotrophic growth rate. The optimum light intensity that produced the attainable maximum growth rate in mixotrophic culture could be estimated by the equation.

ASEAN Journal of Chemical Engineering

Carrageenan is a polysaccharide compound extracted from red seaweed and is widely used by food, c... more Carrageenan is a polysaccharide compound extracted from red seaweed and is widely used by food, cosmetic, and advanced materials industries because of its good properties as an environmentally friendly stabilizer. Carrageenan extraction generally uses alkaline treatment for one full day, where the treatment is to obtain carrageenan quality with good gel characteristics. The use of cellulase enzymes is thought to accelerate the desulfuration process of seaweed, where cellulase enzymes are used to break down cellulose in seaweed cell walls. By using a rapid visco analyzer (RVA), carrageenan was tested to see the pattern and viscosity value. This study aims to determine the effect of enzymatic pretreatment on the profile of carrageenan with a shorter alkalization process compared to the alkalization commonly used by the industry. The results showed that enzymatic treatment before KOH alkalization would produce a carrageenan profile with a viscosity value of 272-360 cP, whereas the NaOH...

This work introduces the modelling of absorption and scattering phenomena in the heterogeneous me... more This work introduces the modelling of absorption and scattering phenomena in the heterogeneous media of a photo-reactor and the prediction of the maximum fraction of light absorption that can be achieved. A new random walk model was proposed with two model parameters, cross sectional areas of absorption and scattering. The Monte Carlo approach was used for the simulation of the model. Isotropic and non-isotropic (forward, backward and side) scattering modes were considered. Any mode or any multiple combination of scattering can be set whenever one takes place. An absorption criterion was defined by comparing the model results with those of Schuster's infinite system. The model was verified experimentally and the agreement was satisfactory. For the experimental system, a heterogeneous medium was made using spherical silica particles and water, and was irradiated with parallel light beams from a laser light source. The model is capable of predicting light intensities and light abs...

Plastic packaging has dominated the waste, and the number is increasing every year. Candy plastic... more Plastic packaging has dominated the waste, and the number is increasing every year. Candy plastic packaging waste is most often considered trivial because of its small size, so it is usually disposed of carelessly. Due to its non-biodegradable, it causes environmental pollution. Edible film packaging is an alternative to reduce the impact of candy packaging waste pollution. The purpose of this study was to obtain the optimum formula of the edible film between corn starch, carrageenan, and rice bran as a hard candy packaging with the Response Surface Methodology (RSM) Central Surface Composite Design using the Design Expert 10.0.7. The prediction data obtained is then verified and tested by t-test at a 5% reliance interval.The optimum formulation of RSM results is 3.4% of corn starch, 1.1% of carrageenan and 0.38% of rice bran with predicted response of water content of 14.51%, WVTR 61,06 g/m/hour, viscosity of 258.8 cP, tensile strength of 107.9 kgf/cm, elongation of 19.41%, and mod...

This paper describes how Indonesia has been amongst the hardest hit in the current Asian economic... more This paper describes how Indonesia has been amongst the hardest hit in the current Asian economic crisis. Based on World Bank and IMF estimates, the short-term economic prospects are not encouraging. The Gross Domestic Product (GDP) was estimated to have declined by 15.6% in the 1998/99 financial year. The construction sector suffered the most (a 40% decline), financial services declined by 27% and the trade, hotel and restaurant sector declined by 21%. Only the agriculture and mining sectors have not been severely affected, although non-oil export earnings fell by 8.8%, notwithstanding severe depreciation of the Rupiah. In the face of ongoing financial sector problems, corporate dislocation and lower international commodity prices, positive economic growth is not expected for 1999/2000. Computable General Equilibrium (CGE) modeling is not a new quantitative approach in academic assessments, but in Indonesia it is relatively new undertaking in research community and its application ...

J Chem Eng Jpn, 2003

Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose... more Mixotrophic culture of Euglena gracilis was carried out using a fed-batch culture system. Glucose and L-glutamic acid were added every 24 hours for 6 days to make the concentrations in the culture medium return to their initial values. We proposed a mixotrophic growth kinetics model to correlate a specific growth rate with a specific rate of energy consumption. In the model, the specific growth rate was proportional to the (1/n)th power of the specific energy consumption rate, and a corresponding yield parameter and a maintenance factor depended on light intensity. The specific growth rate in mixotrophic culture was correlated with incident light intensity by an equation that combined pseudo-photoautotrophic growth rate comparable to that of the modified Aiba model with heterotrophic growth rate. The optimum light intensity that produced the attainable maximum growth rate in mixotrophic culture could be estimated by the equation.

Majalah Ilmiah Pengkajian Industri

Plastic packaging has dominated the waste and the number is increasing every year. Candy plastic ... more Plastic packaging has dominated the waste and the number is increasing every year. Candy plastic packaging waste is most often considered trivial because of its small size so it is usually disposed of carelessly. Every year the candy packaging waste contributes 0.3 billion. Due to its nonbiodegradable, it causes environmental pollution. Edible filmpackaging is an alternative to reduce the impact of candy packaging waste pollution.The purpose of this study was to obtain the optimum formula of edible film between based maize starch, carrageenan and rice bran as a hard candy packaging with the Response Surface Methodology (RSM) Central Surface Composite Design using the Design Expert 10.0.7. The prediction data obtained is then verified and tested by t-test at a 5% reliance interval.The optimum formulation of RSM results is 3,4% of maize starch, 1,1% of carrageenan and 0,38% of rice bran with predicted response of water content of 14,51%, WVTR 61,06 g/m2/hour, viscosity of 258,8 cP, te...

Industria: Jurnal Teknologi dan Manajemen Agroindustri

This research aimed to obtain the best formulation of corn starch, carrageenan, and rice bran as ... more This research aimed to obtain the best formulation of corn starch, carrageenan, and rice bran as the main components of edible film to improve formula’s viscosity, water content, and Water Vapour Transmission Rate (WVTR). This research was an experimental research using Randomized Complete Block Design (RCBD). The first factor was corn starch concentration (1.5%; 2.5%; 3.5%), the second factor was carrageenan concentration (0.67%; 1%; 1.33%), and the third factor was rice bran concentration (0.12%; 0.25%; 0.38%). The analysis of variance showed that the interaction of corn starch, carrageenan, and rice bran has a significant impact on the viscosity, water content, and WVTR value of the edible film. Based on the viscosity, water content, and WVTR value of the edible film, the best formulation was found in the edible film with the corn starch concentration of 2.5%, 1% carrageenan, and 0.25% rice bran. The formula's viscosity value of this edible film was 165.1 ± 5.3 cP, with 14.65...

Current Biochemistry

Capsules are very important in the packaging of pharmaceutical preparations. Commercial capsule s... more Capsules are very important in the packaging of pharmaceutical preparations. Commercial capsule shell is generally made of gelatin from cows and pigs. Alternatives to gelatin from non-animal raw materials can be obtained from polysaccharides like starch and carrageenan. The purpose of this study was to obtain the optimum formula between amylopectin and carrageenan as a raw material subtitute for gelatin capsule shell. Program Design Expert 7.0.0 (trial version) with Response Surface Methodology (RSM) Central Composite Design was used to optimize formula with three variable factors and three response variables. Based on the analysis by determining the adjusted range, program recommends 29 optimization solution with desirability value 1. Formula 6 and 28 was selected for validation with factors 1,01% of amylopectin, 1.01% of carrageenan, 2.17% of glycerin (formula 6) and 3.00% of amylopectin, 2.00% of carrageenan, 2.90% of glycerin (formula 28). Prediction response value was 12.94% of...

Majalah Ilmiah Pengkajian Industri

Penelitian ini dilakukan untuk mendapatkan formula optimum antara amilopektin pati singkong dan k... more Penelitian ini dilakukan untuk mendapatkan formula optimum antara amilopektin pati singkong dan karagenan sebagai bahan baku edible film. Program Design Expert 7.0.0 (trial version) dengan Response Surface Methodology (RSM) Central Composite Design (CCD) digunakan untuk mengoptimasi formula edible film. Variabel bebas yang digunakan yaitu persentase amilopektin, karagenan dan gliserin. Variabel respon yang diukur dan dioptimasi yaitu laju transmisi uap air, kuat tarik dan modulus elastisitas. Hasil optimasi dari program Design Expert 7.0.0 merekomendasikan 15 solusi optimasi dengan nilai desirability tertinggi sebesar 0.821. Formula satu dipilih untuk divalidasi dengan faktor-faktor yaitu amilopektin 3.00 %, karagenan 2.00 %, dan gliserin 2.00 %. Nilai respon prediksi untuk laju transmisi uap air sebesar 16.331 g/m2/24 jam, kuat tarik sebesar 180.657 kgf/cm2 dan modulus elastisitas sebesar 139.262 kgf/cm2. Nilai hasil validasi untuk laju transmis uap air sebesar 16.1027 g/m2/24 jam,...

Journal of Chemical Engineering of Japan, 2003

KAGAKU KOGAKU RONBUNSHU, 1999