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Initial Moisture Content (initial + moisture_content)
Selected AbstractsPECAN TEXTURE AS AFFECTED BY MOISTURE CONTENT BEFORE FREEZING AND THAWING RATEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2001B.B. SURJADINATA ABSTRACT The texture of pecans was determined as affected by initial moisture content before freezing (3 vs 5%), thawing rate (IX, 1.2X, 2.7X, 5.6X), and multiple freeze-thaw cycles (0, 1X, 3X, 6X, 9X, 12X). Texture was determined by instrumental Texture Profile Analysis (TPA) and sensory evaluation. Initial moisture content before freezing had a significant effect on all of the sensory evaluation parameters (hardness, fracturability, cohesiveness, and denseness) and most of the instrumental TPA texture parameters (hardness, fracturability, springiness, resilience, and chewiness). Thawing rate only affected TPA hardness and resilience. TPA fracturability correlated best with sensory fracturability. The sensory panel could not detect any differences between the different thawing rates. The slowest thawing rate affected more parameters than the medium and faster rates. More freeze/thaw cycles significantly decreased most TPA texture values, especially for pecans at higher moisture content. [source] Energy analysis in fluidized-bed drying of large wet particlesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2002S. Syahrul Abstract Energy analysis of a fluidized-bed drying system is undertaken to optimize the fluidized-bed drying conditions for large wet particles (Group D) using energy models. Three critical factors; the inlet air temperature, the fluidization velocity, and the initial moisture contents of the material (e.g., wheat) are studied to determine their effects on the overall energy efficiency to optimize the fluidized bed drying process. In order to verify the model, different experimental data sets for wheat material taken from the literature are used. The results show that the energy efficiencies of the fluidized-bed dryer decrease with increasing drying time and become the lowest at the end of the drying process. It is observed that the inlet air temperature has an important effect on energy efficiency for the material where the diffusion coefficient depends on both the temperature and the moisture content of the particle. Furthermore, the energy efficiencies showed higher values for particles with high initial moisture content while the effect of gas velocity varied depending on the material properties. A good agreement is achieved between the model predictions and the available experimental results. Copyright © 2002 John Wiley & Sons, Ltd. [source] Optimising microwave vacuum puffing for blue honeysuckle snacksINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2010Chenghai Liu Abstract Fresh blue honeysuckle fruit slices were puffed in a microwave vacuum dryer up to a final moisture content about 5% (w.b.). The effect of initial moisture content (IMC) (25,45%), vacuum pressure (VP) (70,90 kPa) and microwave intensity (MI) (10,30 W g,1) on quality attributes, in terms of expansion ratio (ER), hardness (HD), crispness (CR) and colour of the products, were analysed by response surface methodology. Besides the effect of MI on chroma (CH), the high IMC and low VP had a significantly positive impact on the quality attributes of blue honeysuckle snacks. The optimum product qualities, which were ER (1.62 times), HD (5836.31 g), CR (4.48), and CH (28.7) were obtained at an IMC of 38.42%, VP of 82.02 kPa, and MI of 22.42 W g,1. The microwave vacuum method has obvious advantages when puffing the blue honeysuckle snacks. [source] Effect of temperature and initial moisture content on sorption isotherms of banana dried by tunnel drierINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2008Zhengyong Yan Summary Sorption isotherms of intermediate moisture content (IMC) products are essential to predict shelf-life of packaged moisture-sensitive product by modelling moisture uptake during storage and distribution. The effect of temperature and initial moisture content (MC) of IMC banana on the relationship between MC and water activity were investigated. Raw bananas were dried in a tunnel dryer at 2% relative humidity (RH), 70 °C, and a 3.2 ± 0.2 m s,1 air velocity. Drying procedure was carried out a number of times until various IMC levels were obtained (5%, 14%, 22% and 33% db for banana). Sorption isotherms of bananas were determined at 10, 20, 30 and 40 °C. The initial MC of IMC banana had no significant effect on the relationship between MC and water activity according to statistical analysis. All the sorption curves were found to be Type II. BET, GAB, modified GAB, Oswin, Halsey and modified Freundlich models were fitted to the data and it was found that the best results were obtained with a modified Freundlich equation. A secondary modified Freundlich model was built accounting for the effect of aw and temperature on the sample MC. [source] L-methioninase production by Aspergillus flavipes under solid-state fermentationJOURNAL OF BASIC MICROBIOLOGY, Issue 4 2009Ashraf S. A. El-Sayed Abstract Solid-state fermentation was carried out for the production of extra-cellular L-methioninase by Aspergillus flavipes (Bain and Sart.) using nine agro-industrial residues, namely wheat bran, rice bran, wheat flour, coconut seeds, cotton seeds, ground nut cake, lentil hulls, soya beans and chicken feathers. Chicken feathers were selected as solid substrate for L-methioninase production by A. flavipes. The maximum L-methioninase productivity (71.0 U/mg protein) and growth (11 mg protein/ml) of A. flavipes was obtained using alkali pretreated chicken feathers of 50% initial moisture content as substrate supplemented with D-glucose (1.0% w/v) and L-methionine (0.2% w/v). External supplementation of the fermentation medium with various vitamin sources has no overinductive effect on L-methioninase biosynthesis. The partially purified A. flavipes L-methioninase preparation showed highest activity (181 U/ml) at pH 8.0 with stability over a pH range (pH 6,8) for 2 h. L-methioninase activity was increased by preincubation of the enzyme for 2 h with Co2+, Mn2+, Cu2+ and Mg2+ and strongly inhibited by the presence of EDTA, NaN3, Li2+, Cd2+, DMSO and 2-mercaptoethanol. The enzyme preparation has a broad substrate spectrum showing a higher affinity to deaminate L-glycine, N -acetylglucosamine and glutamic acid, in addition to their proteolytic activity against bovine serum albumin, casein, gelatin and keratin. The partially purified enzyme was found to be glyco-metalloproteinic in nature as concluded from the analytical and spectroscopic profiles of the enzyme preparation. The demethiolating activity of the enzyme was also visualized chromogenially. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] MODELING VARIETAL EFFECT ON THE WATER UPTAKE BEHAVIOR OF MILLED RICE (ORYZA SATIVA L.) DURING SOAKINGJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2007B.K. YADAV ABSTRACT Milled rice is soaked until saturation before cooking and other processing. The soaking behavior of the milled rice is affected by varietal factor as well as initial moisture content (M0) of the samples. In the present study, tests were performed for milled whole kernels of 10 rice varieties ranging from low to high amylose content (16,29% d.b.) with three initial moisture levels (approximately 8, 12 and 16% d.b.) for monitoring water uptake in rice kernels during soaking at room temperature (25 ± 1C), in relation to the varietal differences manifested by the physicochemical properties. The water uptake by milled rice kernels took place at a faster rate in the beginning and was followed by a diminishing rate finally leading to a saturated value during soaking. The water uptake of the kernels during soaking could be best expressed by a modified exponential relationship with R2 values ranging from 0.971 to 0.998 for all varieties. The slope of the fitted straight line between actual and estimated moisture contents of milled rice during soaking using a modified exponential relationship was about unity (0.998) with a high R2 value of 0.989 and a root mean square error of 1.2% d.b. The parameters of the fitted model were the function of the M0 and the physicochemical properties of the milled rice. Using developed relationship, the water uptake of the milled rice during soaking could be estimated from its M0 and the physicochemical properties within±10% of the actual values. PRACTICAL APPLICATIONS This information would be useful for the scientific world working on the soaking characteristics of various varieties of rice, mainly for the modeling of the soaking process. It could also be used as a tool in selecting the rice varieties to meet their desired water uptake properties in relation to their psychochemical properties by rice breeder scientists. [source] COFFEE DRYING IN A ROTARY CONDUCTION-TYPE HEATING UNITJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2004GIKURU MWITHIGA ABSTRACT Parchment coffee (Arabica) was dried from an initial moisture content of about 90% to 10% dry basis (db) in a recirculating rotary conduction type heating unit at controlled plenum temperatures of 100, 120 and 140C or controlled product temperatures of 50, 60, and 70C. the temperature of the plenum or moving beans could be maintained at specified levels with small variations during coffee drying experiments. the color and specific gravity of coffee beans exhibited minimum changes as a result of drying operations. the susceptibility of coffee beans to breakage decreased with the lowering of moisture and attained minimum values in the moisture content range of 20 to 30% db. the breakage susceptibility increased sharply with further reduction in moisture content. A drying model, which considered product temperature-time history alone under different operating conditions, estimated the change in moisture content adequately. Such a model could be used for computer-based control of the coffee drying process. [source] OIL POINT PRESSURE OF SOYBEANJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2002O.O. AJIBOLA ABSTRACT The effects of processing conditions such as preheating moisture content (6, 8.3, 10 and 12%-wet basis), heating temperature (70, 85, 100 and 115C) and heating time (15, 20, 25 and 30 min) on the oil point pressure of soybean seed was investigated. It was observed that increase in preheating moisture content from 6.0% to 12.0% (wet basis) increases the oil point pressure. The oil point pressure was found to decrease with increase in temperature and heating time from 70C to 115Cand 15 min to 30 min, respectively. It was also observed that increase in the moisture content during expression (postheating moisture content) from 2.6 to 11.6% increases the oil point pressure and the relationship can adequately be represented by a linear model. The postheating moisture content is affected by the initial moisture content, the heating temperature and heating time; therefore these factors affect the oil point pressure. The oil point pressure values obtained in the study were between 10.4 MPa (for sample at a moisture content of 6.0% heated at 115Cfor 30 min) and 17.2 MPa (for sample at a moisture content of 12.0% heated at 70C for 15 min). [source] PECAN TEXTURE AS AFFECTED BY MOISTURE CONTENT BEFORE FREEZING AND THAWING RATEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2001B.B. SURJADINATA ABSTRACT The texture of pecans was determined as affected by initial moisture content before freezing (3 vs 5%), thawing rate (IX, 1.2X, 2.7X, 5.6X), and multiple freeze-thaw cycles (0, 1X, 3X, 6X, 9X, 12X). Texture was determined by instrumental Texture Profile Analysis (TPA) and sensory evaluation. Initial moisture content before freezing had a significant effect on all of the sensory evaluation parameters (hardness, fracturability, cohesiveness, and denseness) and most of the instrumental TPA texture parameters (hardness, fracturability, springiness, resilience, and chewiness). Thawing rate only affected TPA hardness and resilience. TPA fracturability correlated best with sensory fracturability. The sensory panel could not detect any differences between the different thawing rates. The slowest thawing rate affected more parameters than the medium and faster rates. More freeze/thaw cycles significantly decreased most TPA texture values, especially for pecans at higher moisture content. [source] Reduction of Aflatoxins by Extrusion-Cooking of Rice MealJOURNAL OF FOOD SCIENCE, Issue 7 2006Miren Castells ABSTRACT:, The objective of this work was to determine the reduction of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2) as a function of initial moisture content of samples (24%, 27%, and 30%), barrel temperature (140, 170, and 200 °C), and residence time (30 to 70 s) when artificially contaminated rice meal was extrusion-cooked. Extruded and unextruded samples were analyzed by high-performance liquid chromatography (HPLC). Extrusion-cooking was observed to reduce aflatoxin (AF) content, which ranged from 51% to 95% depending on the type of AF and the studied variables. Only in the case of AFG2 was it found that the higher the temperature, the higher the moisture content, and the longer the residence time, the greater the reduction. Moisture content had a significant influence on reducing AFB2, AFG1, and AFG2 whereas it was not a significant factor affecting the levels of AFB1. Regardless of the type of AF, the lowest reductions were achieved at a temperature of 140 °C. Even though theoretically greater losses would be expected at highest temperature, AFB1 and AFB2 were more reduced by 170 °C than by 200 °C while AFG1 reductions were not statistically different when processing at 170 °C and 200 °C. The decrease of AF followed 1st-order kinetics; the fastest treatment in reducing AF was that at 200 °C when samples containing AFG2 were wetted to 24% and when samples containing AFB1, AFB2, and AFG1 were hydrated to 27%. By contrast, the slowest treatments were observed at a barrel temperature of 140 °C. [source] Heat-moisture Treatments of Cowpea Flour and Their Effects on Phytase InactivationJOURNAL OF FOOD SCIENCE, Issue 2 2005Nicole S. Affrifah ABSTRACT: Samples of finely ground cowpea flour with moisture content adjusted to 10%, 25%, 35% (dry basis) were heated in sealed retort pouches at 70 to 95°C for periods of 2 to 32 min. Phytase showed a high thermal resistance with residual activity ranging between 50% and 95%. Thermal inactivation of cowpea phytase was adequately described by a fractional conversion model based on a 1st-order rate equation. Overall, increasing temperature and initial moisture content resulted in increased enzyme inactivation. Estimated activation energies between 70 and 95°C were 33.3, 37.9, and 43.4 kJ/mol at 10%, 25%, and 35% moisture, respectively. The kinetic models generated were successfully used to predict phytase activity in cowpea flour. [source] Characterization of deep-fat frying in a wheat flour,water mixture model using a state diagramJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2007Pariya Thanatuksorn Abstract BACKGROUND: Crispness is an important characteristic to be controlled in deep-fat fried products. The physical state of food polymers influences the development of cellular structure and textural qualities of fried food. Glassy state is believed to play an important role in the mechanical properties of low-moisture food. Therefore, an understanding of the physicochemical phenomena in the development of fried food structure using a state diagram of the frying process is discussed. RESULTS: Wheat flour models containing 400 and 600 g kg,1 initial moisture content were fried in frying oil at 150 °C for 1,7 min. Thermal properties of wheat flour, structure alteration and textural properties of fried samples were evaluated. The porous structure continuously enlarged when the sample was in the rubbery state. As the frying time was prolonged, the state of the product became glassy due to a decrease in water content, resulting in the ceasing of porous enlargement. Conclusion: The results revealed that physicochemical changes during frying influence the alteration of microstructure and quality of fried food, and the state diagram could be applied to explain the formation of microstructure during the frying process and used as a decision-making tool to choose the proper conditions to provide desirable qualities in fried food. Copyright © 2007 Society of Chemical Industry [source] Citric acid production by Aspergillus niger ATCC 9142 from a treated ethanol fermentation co-product using solid-state fermentationLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009G. Xie Abstract Aims:, To investigate the ability of the citric acid-producing strain Aspergillus niger ATCC 9142 to utilize the ethanol fermentation co-product corn distillers dried grains with solubles for citric acid production following various treatments. Methods and Results:, The ability of A. niger ATCC 9142 to produce citric acid and biomass on the grains was examined using an enzyme assay and a gravimetric method, respectively. Fungal citric acid production after 240 h was higher on untreated grains than on autoclaved grains or acid-hydrolysed grains. Fungal biomass production was enhanced after autoclaving and acid-hydrolysis of the grains. Phosphate supplementation to the grains slightly stimulated citric acid production while methanol addition decreased its synthesis. Using the phosphate-supplemented grains, the optimal incubation temperature, initial moisture content of the grains and the length of fermentation time for ATCC 9142 citric acid production were determined to be 25°C, 82% and 240 h, respectively. Conclusions:,A. niger ATCC 9142 synthesized citric acid on corn distillers dried grains with solubles. The phosphate-treated grains increased citric acid production by the strain. Significance and Impact of the Study:, The ethanol fermentation co-product corn distillers dried grains with solubles could be useful commercially as a substrate for A. niger citric acid production. [source] The Optimisation of Drying Schedules for Pinus radiata Sapwood BoardsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3-4 2004T.A.G. Langrish Optimal drying schedules have been predicted for the drying of Pinus radiata sapwood from an initial moisture content of 140% over a drying time of twenty-four hours for 50mm-thick boards. Initially, a single pair of dry and wet-bulb temperatures (108d,C. 60d,C) over the full time period is estimated to keep the total tangential strain under 50% of the predicted limiting failure value. However, after twelve hours drying, more severe conditions may be used, with the final moisture content predicted to be reduced from 8.2% for a constant set of conditions throughout the schedule (108d,C, 60d,C) to 2.4% when the dry-bulb temperature is raised from 108d,C to 122d,C after twelve hours. It is also possible to use a linearly increasing dry-bulb temperature after twelve hours, rising from 108d,C to 155d,C at the end of drying with a predicted final moisture content of 0.2%. However, to reduce the moisture content to only 10%, there is little difference between the ramped and two-step schedules, both yielding a total drying time of eighteen hours. The two-step schedule would be the easier to in practice. [source] Packed Bed Column Fermenter and Kinetic Modeling for Upgrading the Nutritional Quality of Coffee Husk in Solid-State FermentationBIOTECHNOLOGY PROGRESS, Issue 6 2001Débora Brand Studies were carried out to evaluate solid-state fermentation (SSF) for the upgradation of the nutritional quality of coffee husk by degrading the caffeine and tannins present in it. SSF was carried out by Aspergillus niger LPBx in a glass column fermenter using factorial design experiments and surface response methodology to optimize bioprocess parameters such as the substrate pH and moisture content and aeration rate. The first factorial design showed that the moisture content of the substrate and aeration rate were significant factors for the degradation of toxic compounds, which was confirmed by the second factorial design too. The kinetic study showed that the degradation of toxic compounds was related to the development of the mold and its respiration and also to the consumption of the reducing sugars present in coffee husk. From the values obtained experimentally for the oxygen uptake rate and CO2 evolved, the system determined a biomass yield (Yx/o) of 3.811 (g of biomass)·(g of consumed O2),1 and a maintenance coefficient (m) of 0.0031 (g of consumed O2)·(g biomass of biomass),1·h,1. The best results on the degradation of caffeine (90%) and tannins (57%) were achieved when SSF was carried out with a 30 mL·min,1 aeration rate using coffee husk having a 55% initial moisture content. The inoculation rate did not affect the metabolization of the toxic compounds by the fungal culture. After SSF, the protein content of the husk was increased to 10.6%, which was more than double that of the unfermented husk (5.2%). [source] Single- and dual-porosity modelling of multiple tracer transport through soil columns: effects of initial moisture and mode of applicationEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2001T. Kätterer Summary We investigated the effect of initial moisture contents and mode of application on the displacement of multiple conservative tracers through undisturbed columns of a Humic Gleysol. Bromide was applied at the soil surface and chloride was injected at 5 cm depth. The columns were irrigated with deuterium-enriched water. A dual-porosity model and two single-porosity models were calibrated separately to Br, and Cl, elution curves in the two columns. Elution curves were almost identical for Br, and Cl, under initially wet conditions, whereas the displacement of Br, was faster than that of Cl, in the initially dry column, indicating rapid transport with preferential flow. Only the dual-porosity model described the long-tailing breakthrough of Cl, in the initially dry column adequately. The parameter values giving acceptable fits for ,Br dry' were not compatible with the description of the three other elution curves, which could be adequately modelled with a single set of parameter values. The estimated set of common parameters was validated by comparing with the elution curves of deuterium water, nitrate and sulphate, as well as with resident tracer concentrations at four depths. The results showed that solutes can be displaced much faster when applied at the surface of initially dry soil than when applied to wet soil or when resident in the soil matrix. The simulation results suggest that solute transport under initially dry conditions was governed by preferential flow of infiltration water through macropores by-passing the matrix due to shrinkage cracks and water repellence of matrix surfaces. [source] Energy analysis in fluidized-bed drying of large wet particlesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2002S. Syahrul Abstract Energy analysis of a fluidized-bed drying system is undertaken to optimize the fluidized-bed drying conditions for large wet particles (Group D) using energy models. Three critical factors; the inlet air temperature, the fluidization velocity, and the initial moisture contents of the material (e.g., wheat) are studied to determine their effects on the overall energy efficiency to optimize the fluidized bed drying process. In order to verify the model, different experimental data sets for wheat material taken from the literature are used. The results show that the energy efficiencies of the fluidized-bed dryer decrease with increasing drying time and become the lowest at the end of the drying process. It is observed that the inlet air temperature has an important effect on energy efficiency for the material where the diffusion coefficient depends on both the temperature and the moisture content of the particle. Furthermore, the energy efficiencies showed higher values for particles with high initial moisture content while the effect of gas velocity varied depending on the material properties. A good agreement is achieved between the model predictions and the available experimental results. Copyright © 2002 John Wiley & Sons, Ltd. [source] Variability in Transport Properties for Blackbutt Timber in New South Wales: Within and Between-Tree VariabilityASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2006S. J. Cabardo Variability is a key issue in the processing of biological materials, in this case the hying of hardwood timber. This paper reports the measurements of variability of transport properties. which are relevant to the drying of blackbutt, Eucalyptus pilularis Sm, from northern New South Wales. Specifically, within-tree and between-tree variations are reported for two blackbutt regrowth logs. An analysis of variance showed that some timber properties were affected by the board positions within-trees and between-trees. Circumferential and radial efects were significant for the within- tree variability of most transport properties. Similarly, radial and circumferential effects were signlficant for most of the transport parameters between trees, but can be tentatively stated because only two regrowth logs were assessed. Timber boards with high initial moisture contents had higher rates of diffirsion and low basic densities using principal components analysis. A possible reason is that if there is less wood material per unit volume, these vacant spaces may be occupied by water, and there is also less resistance for diffusive transport of moisture. [source] | |||||||||||||