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Surface Methodology (surface + methodology)
Kinds of Surface Methodology Selected AbstractsRESPONSE SURFACE METHODOLOGY FOR STUDYING THE QUALITY CHARACTERISTICS OF COWPEA (VIGNA UNGUICULATA)-BASED TEMPEHJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2010GEORGE AMPONSAH ANNOR ABSTRACT Response surface methodology was used to optimize the processing conditions in the preparation of cowpea tempeh. The independent factors studied were boiling time (varying from 5 to 30 min), incubation time (varying from 12 to 48 h) and incubation temperatures (varying from 25 to 50C), whereas the dependent factors were protein content, protein solubility, pH, titratable acidity and total color difference (using L, a* and b*). Regression models were generated and adequacy was tested with regression coefficients (R2) and the lack-of-fit tests. Optimum processing conditions were determined by method of superimposition. There was a strong and significant influence (P < 0.01) of the quadratic effect of the incubation time on the protein content of the cowpea tempeh, with similar significance (P < 0.01) noted in protein solubility with increasing boiling time. The optimum processing conditions observed for the preparation of cowpea tempeh were boiling time of about 20 min, incubation time of about 28 h and incubation temperature of about 37C. PRACTICAL APPLICATIONS Response surface methodology (RSM), as a statistical tool, has been effectively used in food process applications. This study embraced the use of RSM in the optimization of the processing conditions involved in the preparation of cowpea tempeh. Superimposition of the contour plots developed from the regression models indicated that cowpea with optimum quality characteristics should be processed at a boiling time of 20 min, incubation time of 28 h and incubation temperature of 37C. These conditions could be adopted for the industrial production of cowpea tempeh. [source] OPTIMIZATION OF PRE-FRY DRYING OF YAM SLICES USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2010OLAJIDE PHILIP SOBUKOLA ABSTRACT The effect of convective hot-air drying pretreatment and frying time at a frying temperature of 170 ± 1C on moisture and oil contents, breaking force (crispness) and color parameters of yam chips was investigated. Response surface methodology technique was used to develop models for the responses as a result of variation in levels of drying temperature (60,80C), drying time (1,5°min) and frying time (2,6°min). Drying pretreatment had a significant effect on oil and moisture contents, breaking force and color parameters of yam chips, with water removal exhibiting a typical drying profile. Response surface regression analysis shows that responses were significantly (P < 0.05) correlated with drying temperature and time and frying time. The optimum pre-fry drying condition observed was a drying temperature of 70,75C for about 3,4 min while frying for 4,5 min. PRACTICAL APPLICATIONS Deep-fat frying is a very important cooking method and a lot of effort has been devoted to manufacturing fried products with lower oil content and acceptable quality parameters. The information provided in this work will be very useful in manufacturing fried yam chips of acceptable quality attributes through the combination of drying pretreatment conditions. The result is very useful in considering different processing variables and responses at the same time as compared with single factor experiment common in the literature. [source] OPTIMIZATION OF PERMEABILIZATION PROCESS FOR LACTOSE HYDROLYSIS IN WHEY USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2009GURPREET KAUR ABSTRACT To overcome the permeability barrier and prepare whole cell biocatalysts with high activities, permeabilization of Kluyveromyces marxianus var. lactis NCIM 3566 in relation to, -galactosidase activity was optimized using cetyltrimethylammonium bromide (CTAB) as permeabilizing agent. Permeabilized whole cells can be advantageous over pure enzyme preparations in terms of cost-effectiveness and increased stability maintained by the intracellular environment. Response surface methodology (RSM) was applied to optimize concentration of CTAB, temperature and the treatment time for maximum permeabilization of yeast cells. The optimum operating conditions for permeabilization process to achieve maximum enzyme activity obtained by RSM were 0.06% (w/v) CTAB concentration, 28C temperature and process duration of 14 min. At these conditions of process variables, the maximum value of enzyme activity was found to be 1,334 IU/g. The permeabilized yeast cells were highly effective and resulted in 90.5% lactose hydrolysis in whey. PRACTICAL APPLICATION , -Galactosidase is one of the most promising enzymes, which has several applications in the food, fermentation and dairy industry. However, the industrial applications of , -galactosidase have been hampered by the costs involved in downstream processing. The present investigation was focused on developing the low-cost technology for lactose hydrolysis based on permeabilization process. Disposal of lactose in whey and whey permeates is one of the most significant problems with regard to economics and environmental impact faced by the dairy industries. Keeping this in view, lactose hydrolysis in whey has been successfully performed using permeabilized Kluyveromyces marxianus cells. Hydrolysis of lactose using , -galactosidase converts whey into a potentially very useful food ingredient, which has immense applications in food industries. Its use has increased significantly in recent years, mainly in the dairy products and in digestive preparations. Lactose hydrolysis causes several potential changes in the manufacture and marketing of dairy products, including increased solubility, sweetness and broader fermentation possibilities. [source] APPLICATION OF RESPONSE SURFACE METHODOLOGY FOR THE OSMOTIC DEHYDRATION OF CARROTSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2006BAHADUR SINGH ABSTRACT Osmotic dehydrations of carrot cubes in sodium chloride salt solutions at different solution concentrations, temperatures and process durations were analyzed for water loss and solute gain. The osmotically pretreated carrot cubes were further dehydrated in a cabinet dryer at 65C and were then rehydrated in water at ambient temperature for 8,10 h and analyzed for rehydration ratio, color and overall acceptability of the rehydrated product. The process was optimized for maximum water loss, rehydration ratio and overall acceptability of rehydrated product, and for minimum solute gain and shrinkage of rehydrated product by response surface methodology. The optimum conditions of various process parameters were 11% salt concentration, 30C osmotic solution temperature and process duration of 120 min. [source] OPTIMIZATION OF NATTOKINASE PRODUCTION CONDUCTION USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2006DJA-SHIN WANG ABSTRACT Natto has attracted worldwide attention because of its health benefits and long history in Japanese food. It has been found that a potent fibrinolytic enzyme named nattokinase, which is extracted from natto, is able to prevent atherosclerosis. The production of nattokinase may be influenced by various factors such as temperature, shaking speed, volume of medium, fermentation time and so forth. Three-step response surface methodology was applied to obtain the optimal operation conditions of the fermentation process in order to maximize the nattokinase yield. The three major steps are described as follows. First, the important factors for fermentation were identified by L8 orthogonal array experiment. The chosen factors were temperature (37 or 45C), shaking speed (110 or 150 rpm), volume of medium (80 or 120 mL), Brix of wheat bran extract (1.5 or 3°), Brix of soy meal extract (1 or 2°), glucose concentration (0.6 or 1.2%) and fermentation time (24 or 36 h). Second, a regression equation was established between the response (i.e., the enzyme activity) and the two statistically significant factors (i.e., the volume of medium and fermentation time). Third, the optimal solutions for the volume of medium and fermentation time were obtained based on the response surface of the regression equation. According to the response surface analysis, the optimal operation conditions for the fermentation process should be 80 mL and 37.0817 h for the volume of medium and the fermentation time, respectively, which resulted in 459.11 FU/mL as the predicted enzyme activity. [source] CONSUMER-BASED OPTIMIZATION OF PEANUT-CHOCOLATE BAR USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3-4 2005EDITH M. SAN JUAN ABSTRACT The acceptability of the sensory properties of a peanut-chocolate bar was optimized for consumer acceptance using response surface methodology. The factors studied included sugar, peanuts, cocoa powder and a process variable, degree of roast. Twenty-seven peanut-chocolate bar formulations with two replications were evaluated for consumer acceptance (n = 168) for overall liking and acceptance of color, appearance, flavor, sweetness and texture using 9-point hedonic scales. In terms of overall liking, the use of dark-roasted peanuts received the largest number of acceptable formulations when compared to the medium- and light-roasted peanuts. Sensory evaluation indicated that sweetness acceptance was the limiting factor for acceptability. An acceptable peanut-chocolate bar can be obtained by using formulations containing 44,54% dark-, medium- or light-roasted peanuts, 1,4% cocoa powder and 41,55% sugar. [source] OPTIMIZATION OF VACUUM PULSE OSMOTIC DEHYDRATION OF CANTALOUPE USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2005WILMER J. FERMIN ABSTRACT The optimum levels of vacuum pressure, concentration of osmotic solution and dehydration time for vacuum pulse osmotic dehydration of cantaloupe were determined by response surface methodology (RSM). The response surface equations ( P < 0.05 and lack of fit > 0.1) explain the 97.6, 88.0 and 97.1% of the variability in weight loss, water loss and °Brix increase, respectively, at 95% confidence level. The canonical analysis for each response indicated that the stationary point is a saddle point for weight loss and °Brix increase, and a point of maximum response for water loss. The region that best satisfied all the constraints (low values in weight loss and °Brix increase, and high value in water loss) is located within the intervals from 49.5 °Brix to 52.5 °Brix for concentration and from 75 min to 84 min for dehydration time at a vacuum pulse of 740 mbar. [source] FORMULATION OF A SOY,COFFEE BEVERAGE BY RESPONSE SURFACE METHODOLOGY AND INTERNAL PREFERENCE MAPPINGJOURNAL OF SENSORY STUDIES, Issue 2010ILANA FELBERG ABSTRACT Coffee consumers (n = 60) tasted and rated samples of a new soy,coffee beverage made from instant coffee, soymilk powder and sugar. Ingredient concentrations (independent variables) varied according to a 23central composite design for overall degree of acceptance. Data were analyzed by analysis of variance (ANOVA), least square difference and response surface methodology, followed by internal preference mapping (IPM) with cluster analysis. ANOVA from the consumers' acceptance data revealed that samples differed significantly (P , 0.05). Although soymilk content did not influence significantly the consumers' acceptance in the tested range, IPM with cluster analysis indicated that at least part of the acceptance differences was based on the soy beverage consumption habit. The final beverage formulation was evaluated cold and hot for overall acceptability (9-point structured hedonic scale) by 112 coffee consumers and the cold beverage reached a good acceptability mean score (6.2) among the participants. PRACTICAL APPLICATIONS The consumption of soy products has been reported to reduce the risk of several diseases and a number of recent studies have found beneficial health properties attributed to coffee. Considering the current consumer trend for healthier alternatives in food products, we decided to combine the health benefits of these two important Brazilian commodities in a functional beverage. In order to optimize the formulation and maximize sensory acceptance, we performed consumers' tests using response surface methodology. Internal preference mapping and cluster analyses were also applied to provide information on the variability of the consumer individual opinions and segment them in groups of similar preference criteria. [source] OPTIMIZATION OF A CHOCOLATE PEANUT SPREAD USING RESPONSE SURFACE METHODOLOGY (RSM)JOURNAL OF SENSORY STUDIES, Issue 3 2004C.A. CHU ABSTRACT Response surface methodology was used to optimize formulations of chocolate peanut spread. Thirty-six formulations with varying levels of peanut (25-90%), chocolate (5-70%) and sugar (5-55%) were processed using a three-component constrained simplex lattice design. The processing variable, roast (light, medium, dark) was also included in the design. Response variables, measured with consumers (n = 60) participating in the test, were spreadability, overall acceptability, appearance, color, flavor, sweetness and texture/mouthfeel, using a 9-point hedonic scale. Regression analysis was performed and models were built for each significant (p < 0.01) response variable. Contour plots for each attribute, at each level of roast, were generated and superimposed to determine areas of overlap. Optimum formulations (consumer acceptance rating of , 6.0 for all attributes) for chocolate peanut spread were all combinations of 29-65% peanut, 9-41% chocolate, and 17-36% sugar, adding up to 100%, at a medium roast. Verification of two formulations indicated no difference between predicted and observed values. [source] Predictive models of the combined effects of curvaticin 13, NaCl and pH on the behaviour of Listeria monocytogenes ATCC 15313 in brothJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2000A. Bouttefroy Thirty-three strains of Listeria monocytogenes belonging to different serotypes were tested for their sensitivity to curvaticin 13, an antilisterial bacteriocin produced by Lactobacillus curvatus SB13, using the well diffusion method in Institut Pasteur agar plates at 37 °C. No relationship between serotype and sensitivity was observed. The sensitivity of this species was strain-dependent and a large variation in tolerance to curvaticin 13 was observed. The combined effects of curvaticin 13 (0,160 AU ml,1), NaCl (0,6% w/v), pH values (5·0,8·2) and incubation time (0,24 h) were investigated on L. monocytogenes ATCC 15313 in trypcase soy,yeast extract broth at 22 °C. For this study, two Doehlert matrices were used in order to investigate the main effects of these factors and their different interactions. The results were analysed using the Response Surface Methodology. Curvaticin 13 had a major inhibitory effect and the response was NaCl concentration-, time- and pH-dependent. This inhibitory activity was the same at pH values between 6·6 and 8·2. Curvaticin 13 was bactericidic at acidic pH values, but the surviving cells resumed growth. For a short incubation time (12 h), the effectiveness of curvaticin 13 was maximal in the absence of NaCl. For longer incubation times (12,48 h), with high NaCl (6%) and curvaticin 13 concentrations (160 AU ml,1), the inhibition of L. monocytogenes was greater than that observed with NaCl or curvaticin 13 alone. [source] Optimization Process of Black Soybean Natto Using Response Surface MethodologyJOURNAL OF FOOD SCIENCE, Issue 6 2009Ming-Chih Shih ABSTRACT:, Response surface methodology (RSM) was used to determine the optimum combinations of 3 factors, cooking time (40 to 120 min), inoculated bacteria populations (101 to 109 cells/100 g), and fermentation time (12 to 36 h) for producing black soybean natto. All of the responses (hardness, viscosity, and trichloacetic acid-soluble nitrogen) were significantly affected by the 3 factors. Fermentation time was the most important factor affecting quality of black soybean natto. Optimum combinations were cooking time 110 min, inoculated bacteria populations 102 to 104 cells/100 g, and fermentation time 30 to 33 h. [source] Optimization of Medium Composition for Nisin Fermentation with Response Surface MethodologyJOURNAL OF FOOD SCIENCE, Issue 6 2008X.-X. Zhou ABSTRACT:, Nisin is an effective food biopreservative widely used in food industry. However, 1 problem of concern is limited production rate and final nisin concentration. A nisin-producing strain, L. lactis Lac2, a mutant strain with high yield of nisin, was obtained in our laboratory recently. In the present study, a fractional factorial design was applied to investigate the main factors that affect the yield of L. lactis Lac2. Central composite experimental design and response surface methodology were adopted to derive a statistical model for optimizing the composition of the medium. The results showed that the optimum medium for nisin production of L. lactis Lac2 was composed of 2.68% sucrose (w/v), 0.5% tryptone (w/v), 1% yeast extract (w/v), 0.3% Tween-80 (w/v), 0.02% MgSO4·7H2O (w/v), 0.81% NaCl (w/v), 1.91% K2HPO4 (w/v), 0.05% ascorbic acid (w/v), and 2% agar (w/v) (if necessary) at pH 6.5. When cultured in the optimum medium, the nisin yield is an average of 3381.81 IU/mL, which nearly doubled the yield when incubated in the initial medium. Also, the concentration of tryptone was decreased while that of the sucrose was increased when compared with CM broth, which means a reduction of the fermentation cost. [source] Fungistatic Activity of Heat-Treated Flaxseed Determined by Response Surface MethodologyJOURNAL OF FOOD SCIENCE, Issue 6 2008Y. Xu ABSTRACT:, The objective of this study was to evaluate the effect of heat treatment on the fungistatic activity of flaxseed (Linum usitatissimum) in potato dextrose agar (PDA) medium and a fresh noodle system. The radial growth of Penicillium chrysogenum, Aspergillus flavus, and a Penicillium sp. isolated from moldy noodles, as well as the mold count of fresh noodle enriched with heat treated flaxseed, were used to assess antifungal activity. A central composite design in the response surface methodology was used to predict the effect of heating temperature and time on antifungal activity of flaxseed flour (FF). Statistical analysis determined that the linear terms of both variables (that is, heating temperature and time) and the quadratic terms of the heating temperature had significant (P < 0.05) effects on the radial growth of all 3 test fungi and the mold count log-cycle reduction of fresh noodle. The interactions between the temperature and time were significant for all dependent variables (P < 0.05). Significant reductions in antifungal activities were found when FF was subjected to high temperatures, regardless of heating time. In contrast, prolonging the heating time did not substantially affect the antifungal activities of FF at low temperature. However, 60% of the antifungal activity was retained after FF was heated at 100 °C for 15 min, which suggests a potential use of FF as an antifungal additive in food products subjected to low to mild heat treatments. [source] Antifungal Activity Stability of Flaxseed Protein Extract Using Response Surface MethodologyJOURNAL OF FOOD SCIENCE, Issue 1 2008Y. Xu ABSTRACT:, The stability of the antifungal activity of flaxseed (Linum usitatissimum) protein extract was evaluated in this study. Response surface methodology (RSM) using Box,Behnken factorial design was used to evaluate the effects of treatment variables, that is, temperature (50 to 90 °C), time (1 to 29 min), and pH (2 to 8), on the residual antifungal activity (RAA) against Penicillium chrysogenum, Fusarium graminearum, Aspergillus flavus, and a Penicillium sp. isolated from moldy noodles. Regression analyses suggested that the linear terms of the temperature and time had significant (P < 0.05) negative effects on the RAA against all test fungi, whereas that of pH had a significant (P < 0.1) positive role on the RAA of all 3 fungi. In addition, the RAA was significantly (P < 0.05) affected by the quadratic terms of time for all fungi, and the quadratic term of temperature played a significant (P < 0.1) role on RAA against F. graminearum. One interaction term (temperature-pH) was found to significantly (P < 0.1) affect the RAA against both Penicillium strains tested. The results indicated that , 90% antifungal activity was lost after the protein extracts were heated at 90 °C for 8 min except for F. graminearum. At pasteurization condition, , 50% activity was retained except for P. chrysogenum. The results also suggested that neutral and alkaline pH favored the antifungal activity stability of the protein extracts. Thus, flaxseed protein might be promising if used as a preservative in foods with neutral or alkaline pH requiring mild heat treatments. [source] Response Surface Methodology for Reduction of Pinking in Cooked Turkey Breast Mince by Various Dairy Protein CombinationsJOURNAL OF FOOD SCIENCE, Issue 3 2000A.J. Slesinski ABSTRACT: Nonfat dry milk (NFDM), sodium caseinate (SC), whey protein concentrate (WPC), and combinations of each were evaluated for abilities to reduce pink color development in cooked, ground, uncured turkey breast. Protein treatments were also evaluated in the presence of pink-color-generating ligands (nicotinamide, 1%, sodium nitrite, 10 ppm, and sodium nitrate, 50 ppm) with and without ethylenedinitrilo-tetraacetic acid disodium salt (200 ppm). NFDM and WPC at levels as low as 1.5% were effective in reducing CIE a* values (P < 0.05) regardless of ligand treatment; SC was not. EDTA reduced pink color within all protein and ligand treatments. Poultry producers can reduce pink color development in further-processed products by selective addition of dairy proteins. [source] Optimization of Crotonaldehyde Oxidation Catalyst using Response Surface MethodologyCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2008J.-H. Tang Abstract Crotonic acid was produced by oxidation of crotonaldehyde over molybdophosphoric acid supported on activated carbon. The full 23 central composite design was performed and aimed at optimizing oxidation catalysts to maximize the yield of crotonic acid. Response surface methodology was applied to obtain a second-order polynomial model and to generate the optimum conditions, with a loading of molybdophosphoric acid of 0.25, mass ratio of catalyst to crotonaldehyde of 0.025 and mass ratio of vanadium pentoxide to molybdophosphoric acid of 0.08. The crotonic acid yield was 66.7,% under these conditions. Three experiments were conducted using the same optimum conditions, and therefore, good agreement was observed between the experimental data and the predicted values obtained from the model, by comparison [source] The Degree of Desulphurization of a Limestone/Gypsum Wet FGD Spray Tower using Response Surface MethodologyCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 4 2007Z. Zhao Abstract The degree of desulphurization was studied using response surface methodology (RSM), which enables effect examinations of parameters with a moderate number of experiments. All experiments were conducted in a lab-scale spray tower for limestone/gypsum wet flue gas desulphurization (FGD). The model flue gas was prepared from air and SO2 gas. The SO2 concentrations in the gas phase were determined by a multi-method analyzer. The degree of desulphurization correlated well with operating parameters, including pH, L/G, T, and v, with a determination coefficient R,Sq of 0.964. Effect tests indicate that L/G has the most significant influence on the degree of desulphurization. The interactions of L/G with pH, and with v, both play important roles. The result indicates that the evolutive response surface model is helpful to describe the degree of desulphurization of the limestone/gypsum wet FGD spray tower. [source] Use of chemometric methodology in optimizing conditions for competitive binding partial filling affinity capillary electrophoresisELECTROPHORESIS, Issue 16 2008Ruth E. Montes Abstract This work expands the knowledge of the use of chemometric response surface methodology (RSM) in optimizing conditions for competitive binding partial filling ACE (PFACE). Specifically, RSM in the form of a Box,Behnken design was implemented in flow-through PFACE (FTPFACE) to effectively predict the significance of injection time, voltage, and neutral ligand (neutral arylsulfonamide) concentration, [Lo], on protein,neutral ligand binding. Statistical analysis results were used to create a model for response surface prediction via contour and surface plots at a given maximum response (,RMTR) to reach a targeted Kb,=,2.50×106,M,1. The adequacy of the model was then validated by experimental runs at the optimal predicted solution (injection time,=,2.3,min, voltage,=,11.6,kV, [Lo],=,1.4,,M). The achieved results greatly extend the usefulness of chemometrics in ACE and provide a valuable statistical tool for the study of other receptor,ligand combinations. [source] On-line sample stacking and short-end injection CE for the determination of fluoxetine and norfluoxetine in plasma: Method development and validation using experimental designsELECTROPHORESIS, Issue 18 2007Chia-Chia Lu Abstract A short-end injection CE method combining field-amplified sample stacking (FASS) is presented for the analysis of fluoxetine (FL) and norfluoxetine in plasma. In this study, FASS enhanced the sensitivity about 1100-fold, while short-end injection reduced the analysis time to less than 4,min. Parameters involved in the separations were investigated using a central composite design (CCD) and response surface methodology to optimize the separation conditions in a total of only 32 runs. Samples injected into the capillary for 99.9,s at a voltage of ,5,kV were stacked in a water plug (0.5,psi, 9,s). Baseline resolution of FL and its major metabolite was achieved using a BGE formulation consisting of phosphate,triethanolamine at low pH, and a separation voltage of ,10,kV. Five percent methanol was added as organic modifier to enhance selectivity and resolution. The linear range was between 10 and 500,ng/mL (r >0.9946), covering the expected plasma therapeutic ranges. The LOD in plasma were 4,ng/mL (S/N,=,3), a value comparable to that obtained using LC-MS, showing the success of the on-line stacking technique. Our method was also successfully validated in quantification and pharmacokinetic studies with three volunteer plasma samples and could be applied to pharmacogenetic studies. [source] Towards Higher Laccase Activities Produced by Aquatic Ascomycetous Fungi Through Combination of Elicitors and an Alternative SubstrateENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2008C. Junghanns Abstract Laccases are versatile biocatalysts with various potential biotechnological applications, e.g. the treatment of industrial waste waters, the detoxification of environmental pollutants, or the functionalization of renewable polymeric materials. Central composition experimental design and response surface methodology was applied to optimize the production of laccase by the aquatic ascomycetous fungi, Phoma sp. UHH 5-1-03 and Coniothyrium sp.,Kl-S5, in shake flasks. A complex plant-based medium (tomato juice) and two elicitors (Remazol Brilliant Blue R [RBBR] and CuSO4) were tested in combination at three concentrations. The highest laccase activity of 6322,±,403,U/L was achieved on day,9 for Phoma sp. Coniothyrium sp. exerted a maximum laccase activity of 3035,±,111 U/L on day,4. Optimal conditions were 30,% tomato juice and 450,mg/L RBBR for both strains. A concentration of 250,,M CuSO4 led to highest laccase activities in cultures of Coniothyrium sp., and 50,,M CuSO4 was most effective for Phoma sp. A remarkable synergistic effect of tomato juice and RBBR on laccase production was observed for both strains. The upscaling potential of the optimal induction conditions was demonstrated in a lab-scale fermenter which resulted in maximum activities of 11030,±,177,U/L on day,6 for Phoma sp. and 11530,±,161,U/L on day,9 for Coniothyrium sp. This study therefore presents a promising alternative for laccase production in ascomycetes based on a cheap complex substrate in combination with two elicitors. [source] Antioxidant capacity of rapeseed meal and rapeseed oils enriched with meal extractEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2010Aleksandra Szyd, owska-Czerniak Abstract Response surface methodology (RSM) was used to evaluate the quantitative effects of two independent variables: solvent polarity and temperature of the extraction process on the antioxidant capacity (AC) and total phenolics content (TPC) in meal rapeseed extracts. The mean AC and TPC results for meal ranged between 1181,9974,µmol TE/100,g and 73.8,814,mg sinapic acid/100,g of meal. The experimental results of AC and TPC were close to the predicted values calculated from the polynomial response surface models equations (R2,=,0.9758 and 0.9603, respectively). The effect of solvent polarity on AC and TPC in the examined extracts was about 3.6 and 2.6 times greater, respectively, than the effect of processing temperature. The predicted optimum solvent polarity of ,,=,78.3 and 63.8, and temperature of 89.4 and 74.2°C resulted in an AC of 10,014,µmol TE/100,g and TPC of 863,mg SAE/100,g meal, respectively. The phenolic profile of rapeseed meal was determined by an HPLC method. The main phenolics in rapeseed meal were sinapine and sinapic acid. Refined rapeseed oils were fortified with an extract , rich in polyphenols , obtained from rapeseed meal. The supplemented rapeseed oil had higher AC and TPC than the refined oil without addition of meal extracts. However, AC and TPC in the enriched oils decreased during storage. The TPC in the studied meal extracts and rapeseed oils correlated significantly (p<0.0000001) positively with their AC (R2,=,0.9387). Practical applications: Many bioactive compounds extracted from rapeseed meal provide health benefits and have antioxidative properties. Therefore, it seems worth to consider the application of antioxidants extracted from the rapeseed meal for the production of rapeseed oils with potent AC. Moreover, antioxidants extracted from the rapeseed meal were added to refined rapeseed oil in order to enhance its AC. AC was then tested by FRAP assay. FRAP method is based on the reduction of the ferric tripyridyltriazine (Fe3+ -TPTZ) complex to the ferrous tripyridyltriazine (Fe2+ -TPTZ), and it is simple, fast, low cost, and robust method. FRAP method does not require specialized equipment and can be performed using automated, semi-automatic, or manual methods. Therefore the proposed FRAP method can be employed by the fat industry laboratories to asses the AC of rapeseed oils and meal. [source] Optimization of industrial-scale deodorization of high-oleic sunflower oil via response surface methodologyEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 3 2008Vito Martin Abstract Optimization of industrial-scale deodorization of high-oleic sunflower oil (HOSO) via response surface methodology is presented in this study. The results of an experimental program conducted on an industrial-scale deodorizer were analyzed statistically. Predictive models were derived for each of the oil quality indicators (QI) in dependence on the studied variable deodorization process parameters. The deodorization behavior of some minor components was analyzed on a pilot-scale deodorizer. For comparison, a similar experimental program was also performed on the laboratory-scale. The results of this study demonstrate that optimization of the deodorization process requires a suitable compromise between often mutually opposing demands dictated by different oil QI. The production of HOSO with top-quality organoleptic and nutritional values (high tocopherol and phytosterol contents and low free and trans fatty acid contents) and high oxidative stability demands deodorization temperatures in the range between 220 and 235,°C and a total sparge steam above 2.0% (wt/wt in oil). The response surface methodology provides the tools needed to identify the optimum deodorization process conditions. However, the laboratory-scale experiments, while showing similar response characteristics of QI in dependence on the process parameters and thus helpful as a guide, are of limited value in the optimization of an industrial-scale operation. [source] Optimization of activated carbon-based decontamination of fish oil by response surface methodologyEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2007Åge Oterhals Abstract The effect of activated carbon (AC) adsorption on the reduction of persistent organic pollutants (POP) in fish oil was studied based on response surface methodology at a 5-g/kg AC inclusion level. Pretreatment of the oil by alkali refining and bleaching increased the POP levels. The tested process variables (contact time and temperature) affected the AC adsorption rate and significant first- and second-order response models could be established. Polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/F) showed a very rapid adsorption behavior and the concentration and toxic equivalent (TEQ) level could be reduced by 99%. Adsorption of dioxin-like polychlorinated biphenyls (DL-PCB) was less effective and depended on ortho substitution, i.e. non- ortho PCB were adsorbed more effectively than mono- ortho PCB with a maximum of 87 and 21% reduction, respectively, corresponding to a DL-PCB-TEQ reduction of 73%. A common optimum for both PCDD/F and DL-PCB adsorption could not be identified. AC treatment had no effect on the level of polybrominated diphenyl ether flame retardants. The differences in adsorption patterns may be explained based on molecular conformation. No change in oil quality could be observed based on oxidation parameters. Compliance with present PCDD/F and DL-PCB legislation levels in fish oil can be achieved based on AC adsorption. [source] Optimization of ingredients for the formulation of a direct acidified whey based lassi-like beverageINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2008KALYANI NAIR Samples of direct acidified whey based lassi like beverage were prepared with different proportions of guar gum, CMC and inulin and were examined for sensory and physical attributes. The optimisation was carried out using central composite rotatory design (CCRD) of response surface methodology (RSM). Response surface analysis revealed that sensory scores for flavour, consistency, colour and appearance and overall acceptability of lassi like beverage varied from 6.50 to 7.25, 6.16 to 7.12, 6.20 to 7.41 and 5.96 to 7.20 respectively. The results of analysis showed that all the examined model solutions had significant influence on the different parameters indicating that the statistical model designed for these attributes fitted well in all the aspects of model efficiency check (R2 >85%). [source] Fat, wheat bran and salt effects on cooking properties of meat patties studied by response surface methodologyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2010Hasibe Tekin Summary Response surface methodology was used to investigate the main effects and interactions of composition (processing) variables such as fat (10,30%), wheat bran (5,15%) and NaCl (0,2%) on cooking properties of beef patties. In addition, the ridge analysis was conducted to find the values of processing variables that maximise and minimise the cooking parameters (moisture retention, fat retention, reduction in thickness, reduction in diameter, cooking yield, shrinkage and water-holding capacity). It was found that the moisture and fat retention, reduction in thickness and cooking yield values decreased; however, reduction in diameter and shrinkage values increased, respectively, as the amount of fat increased. However, wheat bran addition increased fat retention, moisture retention, cooking yield and water-holding capacity values of the patties. Increasing NaCl levels decreased water-holding capacity value by its quadratic effect and moisture and fat retention value by its interaction effect with wheat bran. [source] Review article: Basic steps in adapting response surface methodology as mathematical modelling for bioprocess optimisation in the food systemsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2010Titus U. Nwabueze Summary Techniques involving choosing process combinations for optimisation without due consideration for relevant experimental designs is scientifically unreliable and irreproducible. Mathematical modelling, of which response surface methodology (RSM) is one, provides a precise map leading to successful optimisation. This paper identified key process variables, building the model and searching the solution through multivariate regression analysis, interpretation of resulting polynomial equations and response surface/contour plots as basic steps in adapting the central composite design to achieve process optimisation. It also gave information on appropriate RSM software packages and choice of order in RSM model and data economy in reducing the factorial experiments from large number parameter combinations to a far less number without losing any information including quadratic and interaction (if present) effects. It is expected that this paper will afford many food scientists and researchers the opportunity for adapting RSM as a mathematical model for achieving bioprocess optimisation in food systems. [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] Optimisation of the medium composition for production of protease and soybean peptides by Bacillus subtilis SHZ using response surface methodologyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2008Bo Yu Summary Responses surface methodology was employed to enhance the production of protease and soybean peptides by Bacillus subtilis SHZ. For screening of medium composition significantly influencing protease and soybean peptides yield, the two-level Plackett,Burman design was used. Among thirteen variables tested; KH2PO4, glucose and defatted soybean flour (DSF) were selected based on their high significant effect on both protease activity and soybean peptides yield. Then, a three-level Box,Behnken design was employed to optimise the medium composition for the production of the protease and soybean peptides in submerged fermentation. Mathematical models were then developed to show the effect of each medium composition and their interactions on the production of protease and soybean peptides. The model estimated that, the maximal protease activity (320 ± 1 U mL,1) could be obtained when the concentrations of glucose, KH2PO4, DSF were set at 8,9 g L,1, 2,3 g L,1, 55,65 g L,1, respectively; while a maximal yield of soybean peptides (8.5 ± 0.1 g L,1) could be achieved when the concentrations of glucose, KH2PO4, DSF were set at 7,9 g L,1, 3,4 g L,1 and 55,58 g L,1, respectively. These predicted values were also verified by validation experiments. [source] Rheological study of ternary mixtures and pectic gels of red fruit pulpsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2007Charles Windson Isidoro Haminiuk Summary In this work, the rheological behaviour of ternary mixtures of strawberry, blackberry and raspberry pulps in steady shear was studied using the response surface methodology. In addition, the rheology of pectic gels extracted from these pulps was investigated by means of oscillatory shear tests. The flow curves were adequately described by the rheological model of Herschel,Bulkley. All the formulations analysed exhibited shear-thinning behaviour. The rheological responses were influenced by the difference in pulp proportions and also by the temperatures (20 and 60 °C). The quadratic and cubic models used to fit the response were considered suitable owing to the higher values of determination coefficient (R2). The pectic gels from strawberry, blackberry and raspberry showed a strong gel character, with strawberry presenting the stronger gel, which was confirmed by the Cox,Merz experiment, degree of esterification and average molecular weight data. [source] Effects of temperature, ammonium and glucose concentrations on yeast growth in a model wine systemINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2006Daniela D'Amato Summary In enology, alcoholic fermentation is a complex process involving several mechanisms. Slow and incomplete alcoholic fermentation is a chronic problem for the wine industry and factors leading to sluggish and stuck fermentations have been extensively studied and reviewed. The most studied cause of sluggish and stuck fermentation is the nitrogen content limitation. Nevertheless, other factors, such as temperature of fermentation and sugar concentration can affect the growth of yeasts. In this study we modelled the yeast growth-cycle in wine model system as a function of temperature, sugar and ammonium concentrations; the individual effects and the interaction of these factors were analysed by means of a quadratic response surface methodology. Cell concentrations and weight loss were monitored in the whole wine fermentation process. The results of central composite design show that lower is the availability of nitrogen, higher is the cell growth rate; moreover, initial nitrogen concentration also influences survival time of Saccharomyces cerevisiae. [source] | ||||||||||||||||||||||||||||||||||