Commenced in January 2007
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Edition: International
Paper Count: 6

Search results for: pretreatments

6 Effect of Chemical Pretreatments and Dehydration Methods on Quality Characteristics of Tomato Powder and Its Storage Stability

Authors: Reihaneh Ahmadzadeh Ghavidel, Mehdi Ghiafeh Davoodi

Abstract:

Dehydration process was carried out for tomato slices of var. Avinash after giving different pre-treatments such as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl). Untreated samples served as control. Solar drier and continuous conveyor (tunnel) drier were used for dehydration. Quality characteristics of tomato slices viz. moisture content, sugar, titratable acidity, lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning as affected by dehydration process were studied. Storage study was also carried out for a period of six months for tomato powder packed into different types of packaging materials viz. metalized polyester (MP) film and low density poly ethylene (LDPE). Changes in lycopene content and non-enzymatic browning (NEB) were estimated during storage at room temperature. Pretreatment of 5 mm thickness of tomato slices with calcium chloride in combination with potassium metabisulphite and drying using a tunnel drier with subsequent storage of product in metalized polyester bags was selected as the best process.

Keywords: Drying pretreatments, Solar drying, Tomato powder, Tunnel drying

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5 Studies on Physiochemical Properties of Tomato Powder as Affected by Different Dehydration Methods and Pretreatments

Authors: Reihaneh Ahmadzadeh Ghavidel, Mehdi Ghiafeh Davoodi

Abstract:

Tomato powder has good potential as substitute of tomato paste and other tomato products. In order to protect physicochemical properties and nutritional quality of tomato during dehydration process, investigation was carried out using different drying methods and pretreatments. Solar drier and continuous conveyor (tunnel) drier were used for dehydration where as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl) selected for treatment.. lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning in addition to moisture, sugar and titrable acidity were studied. Results show that pre-treatment with CaCl2 and NaCl increased water removal and moisture mobility in tomato slices during drying of tomatoes. Where CaCl2 used along with KMS the NEB was recorded the least compared to other treatments and the best results were obtained while using the two chemicals in combination form. Storage studies in LDPE polymeric and metalized polyesters films showed less changes in the products packed in metallized polyester pouches and even after 6 months lycopene content did not decrease more than 20% as compared to the control sample and provide extension of shelf life in acceptable condition for 6 months. In most of the quality characteristics tunnel drier samples presented better values in comparison to solar drier.

Keywords: Dehydration, Tomato powder, Lycopene, Browning

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4 Effect of Surface Pretreatments on Nanocrystalline Diamond Deposited On Silicon Nitride Substrates

Authors: D.N Awang Sh'ri, E. Hamzah

Abstract:

The deposition of diamond films on a Si3N4 substrate is an attractive technique for industrial applications because of the excellent properties of diamond. Pretreatment of substrate is very important prior to diamond deposition to promote nucleation and adhesion between coating and substrate. Deposition of nanocrystalline diamonds films on silicon nitride substrate have been carried out by HF-CVD technique using mixture of methane and hydrogen gases. Different pretreatment of substrate including chemical etching consists of hot acid etching and basic etching and mechanical etching were used to study the quality of diamond formed on the substrate. The structure and morphology of diamond coating have been studied using X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) while diamond film quality has been characterized using Raman spectroscopy. AFM was used to investigate the effect of chemical etching and mechanical pretreatment on the surface roughness of the substrates and the resultant morphology of nanocrystalline diamond. It was found that diamond film deposited on as-received, basic etched and grinded substrate shows the morphology of cauliflower while blasted and acidic etched substrates produce smooth, continuous diamond film. However, the Raman investigation did not show any deviation in quality of diamond film for any pretreatment.

Keywords: Nanocrystalline diamond, Chemical VaporDeposition, Pretreatment, Silicon Nitride

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3 Optimization of NaOH Thermo-Chemical Pretreatment to Enhance Solubilisation of Organic Food Waste by Response Surface Methodology

Authors: H. Junoh, K. Palanisamy, C. H. Yip, F. L. Pua

Abstract:

This study investigates the influence of low temperature thermo-chemical pretreatment of organic food waste on performance of COD solubilisation. Both temperature and alkaline agent were reported to have effect on solubilizing any possible biomass including organic food waste. The three independent variables considered in this pretreatment were temperature (50-90oC), pretreatment time (30-120 minutes) and alkaline concentration, sodium hydroxide, NaOH (0.7-15 g/L). The maximal condition obtained were 90oC, 15 g/L NaOH for 2 hours. Solubilisation has potential in enhancing methane production by providing high amount of soluble components at early stage during anaerobic digestion.

Keywords: Food waste, pretreatments, respond surface methodology, ANOVA, anaerobic digestion.

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2 A Comparison of Dilute Sulfuric and Phosphoric Acid Pretreatments in Biofuel Production from Corncobs

Authors: Jirakarn Nantapipat, Apanee Luengnaruemitchai, Sujitra Wongkasemjit

Abstract:

Biofuels, like biobutanol, have been recognized for being renewable and sustainable fuels which can be produced from lignocellulosic biomass. To convert lignocellulosic biomass to biofuel, pretreatment process is an important step to remove hemicelluloses and lignin to improve enzymatic hydrolysis. Dilute acid pretreatment has been successful developed for pretreatment of corncobs and the optimum conditions of dilute sulfuric and phosphoric acid pretreatment were obtained at 120 °C for 5 min with 15:1 liquid to solid ratio and 140 °C for 10 min with 10:1 liquid to solid ratio, respectively. The result shows that both of acid pretreatments gave the content of total sugar approximately 34–35 g/l. In case of inhibitor content (furfural), phosphoric acid pretreatment gives higher than sulfuric acid pretreatment. Characterizations of corncobs after pretreatment indicate that both of acid pretreatments can improve enzymatic accessibility and the better results present in corncobs pretreated with sulfuric acid in term of surface area, crystallinity, and composition analysis.

Keywords: Corncobs, Pretreatment, Sulfuric acid, Phosphoric acid.

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1 Enhancement of Essential Oil from Agarwood by Subcritical Water Extraction and Pretreatments on Hydrodistillation

Authors: Nuttawan Yoswathana, M. N. Eshiaghi, K. Jaturapornpanich

Abstract:

The traditional method for essential oil extraction from agarwood (Aquilaria Crassna) is to soak it in water and follow with hydrodistillation. The effect of various agarwood pretreatments: ethanol, acid, alkaline, enzymes, and ultrasound, and the effect of subcritical water extraction(SWE) was studied to compare with the traditional method. The major compositions of agarwood oil from hydrodistillation were aroma compounds as follow: aristol-9-en-8- one (21.53%), selina-3, 7(11)-diene (12.96%), τ-himachalene (9.28%), β-guaiene (5.79%), hexadecanoic acid (4.90%) and guaia- 3,9-diene (4.21%). Whereas agarwood oil from pretreatments with ethanol and ultrasound, and SWE got fatty acid compounds. Extraction of agarwood oil using these pretreatments could improve the agarwood oil yields up to 2 times that of the traditional method. The components of the pretreated sample with diluted acid (H2SO4) at pH 4 gave quite similar results as the traditional method. Therefore, the enhancement of essential oil from agarwood depends on requirement of type of extracted oil that involved extraction methods.

Keywords: Agarwood, aquilaria crassna, hydrodistillation, subcritical water extraction.

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