Extraction optimization of a hydrocolloid extract from cress seed (Lepidium sativum) using response surface methodology

Extraction conditions for maximum values of yield, viscosity and minimum protein content of hydrocolloid extract from Lepidium sativum seed were investigated using response surface methodology. A Central Composite Face Design (CCFD) with four independent variables: temperature (25–85 °C); pH (3–10); extraction time (10–25 min) and water to seed ratio (10:1–80:1) was used to study the response variables (yield, viscosity and protein content). Data analysis showed that all the variables significantly (p < 0.05) affected the extraction yield and viscosity, whereas the effect of water to seed ratio on protein content was not significant (p > 0.05). Applying a desirability function method the optimum parameters were: extraction temperature 35 °C, pH 10, water to seed ratio of 30:1 and an extraction time of 15 min. At this optimum point, apparent viscosity, yield and protein content were 0.2 Pa s, 6.46% and 0.57%, respectively. The experimental values were very close to the predicted values and were not statistically different (p > 0.05).     

Optimization of conditions for extraction of acid-soluble collagen from grass carp (Ctenopharyngodon idella) by response surface methodology

Grass carp is a freshwater fish species widely known by consumers over the world. Its skin has abundant collagen which possesses many healthy effects. The optimal conditions for collagen extraction were determined by response surface methodology in this work. Box–Behnken design was applied to evaluate the effects of three independent variables (acetic-acid concentration, temperature and time) on the acid-soluble collagen yield of grass carp skin. Correlation analysis of the mathematical-regression model indicated that quadratic polynomial model could be employed to optimize the extraction of acid-soluble collagen. From response surface plots, acetic-acid concentration, temperature and time exhibited interactive effects on the extraction of acid-soluble collagen. The optimal conditions to obtain the highest acid-soluble collagen yield of grass carp skin were an acetic-acid concentration of 0.54 M, a temperature of 24.7 °C and a time of 32.1 h. Under these optimal conditions, the experimental values agreed with the predicted values, using analysis of variance, indicating a high goodness of fit of the model used and the success of response surface methodology for modeling extraction of acid-soluble collagen from grass carp skin.

Industrial relevance

Grass carp is a freshwater fish species with important economic significance. The annual production of grass carp in China was 3.86 million tons in 2005 which was the highest among all the freshwater fish species (http://www.agri.ac.cn/DataIss/ZY/QT/200610/17688.html). The weight of skin accounts for approximately 9% of whole fish. It is interesting to find a way to improve its value. In this work, collagen was extracted from grass carp skin by acetic acid and a mathematical model of extraction was built by response surface methodology. The effects of acetic-acid concentration, extraction time and temperature were under investigation. The results showed that there is an optimal condition to obtain the highest collagen yield. The optimal condition was determined to be an acetic-acid concentration of 0.54 M, a temperature of 24.7 °C and a time of 32.1 h. This research is helpful to develop a new product using grass carp and to fully use this sort of fish resource.     

响应面法优化超声辅助提取核桃叶多酚的工艺研究

首次以陇南核桃叶为原料,运用超声波辅助提取技术对核桃叶中的多酚类物质进行提取,在温度为40℃,超声功率为110W的条件下,考察了料液比、超声时间、乙醇浓度对多酚提取率的影响,并利用响应面法优化了提取工艺,得出最佳工艺参数为:料液比为1∶10,超声提取时间为10min,乙醇浓度为70%,在最佳提取工艺的条件下,核桃多酚的含量可达到4.04mg/g,为核桃叶多酚的进一步开发提供了依据。     

Optimizing conditions for anthocyanins extraction from purple sweet potato using response surface methodology (RSM)

Optimization for purple sweet potato (Ipomoea batatas (L.) Lam) anthocyanins (PSPAs) extraction was investigated using response surface methodology in this paper. PSPAs were extracted using acid-ethanol at different extraction temperature (40-80 °C), time (60-120 min) and solid-liquid ratio (1:15-1:30). The combined effects of extraction conditions on PSPAs yield and color attributes (expressed as L*, C* and H) were studied using a three-level three-factor Box-Behnken design. The results showed that The highest yield (158 mg/100 g dw) of PSPAs were reached at the temperature 80 °C, extraction time 60 min, and solid-liquid ratio 1:32. PSPAs yield indicated a high and significant correlation with L^* (P<0.05; r=−0.961) and it was significantly affected by extraction temperature (P<0.01) and solid-liquid ratio (P<0.05).     

Optimisation of the solvent extraction of bioactive compounds from Parkia speciosa pod using response surface methodology

Central composite design was employed to optimise the buffer-to-solids ratio (X₁: 20–50 ml/g), incubation temperature (X₂: 35–55 °C) and time (X₃: 100–200 min), obtaining extracts from Parkia speciosa pod with high total phenolic and flavonoid contents and high antioxidant activities. Analysis of variance showed that the contribution of a quadratic model was significant for the responses. An optimisation study using response surface methodology was performed and 3D response surfaces were plotted from the mathematical models. The optimal conditions based on combination responses were: X₁ = 20 ml/g, X₂ = 35–36 °C and X₃ = 100–102 min. These optimum conditions yielded total phenolic contents of 664–668 mg gallic acid equivalents/100 g, total flavonoid contents of 47.4–49.6 mg pyrocatechol equivalents/100 g, %DPPH_sc of 81.2–82.1%, %ABTS_sc of 78.2–79.8% and FRAP values of 3.2–3.3 mM. Close agreement between experimental and predicted values was found. This methodology could be applied in the extraction of bioactive compounds in the natural product industry.     

Optimization of extraction conditions for improving solubility of peanut protein concentrates by response surface methodology

By ethanol precipitation and physical separation procedures, the peanut protein concentrate (PPC) was isolated from defatted peanut flour (DPF) and the extraction times were determined as twice. The effects of liquid-to-solid ratio, ethanol concentration and reaction temperature on the solubility of PPC were studied for the primary extraction and the later two factors were studied for the second extraction by response surface methodology (RSM). The results showed that for both of the second-order models, the coefficient determination (R²) was good and a liquid-to-solid ratio of 11.79: 1 (v/w), an ethanol concentration of 85 mL/100 mL, an extract temperature of 36.35 °C for the primary extraction and a corresponding list of variables of 8:1 (v/w), 97.50 mL/100 mL and 38.40 °C for the secondary extraction were found to be optimal for the protein extraction from defatted peanut flour. By means of additional experiments, the adequacy of the model was confirmed.     

Optimization of extraction process of crude polysaccharides from boat-fruited sterculia seeds by response surface methodology

Response surface methodology (RSM) was applied to optimize the extraction of crude polysaccharides from boat-fruited sterculia seeds. A central composite design was used for experimental design and analysis of the results to obtain the optimal extraction conditions. Extraction temperature, pH, extraction time and water to seed ratio were found to have a significant influence on the yield and purity of the extracted crude polysaccharides, while the three other factors except the water to seed ratio also significantly affected the relative viscosity. Based on the RSM analysis, optimum conditions were: temperature 60–65 °C, time 2.3–3.1 h, pH at 7.0 and water to seed ratio at 75:1. Under the optimized conditions, the experimental values were in close agreement with values predicted by the model. The crude polysaccharides prepared under optimum conditions contained 58.2% total carbohydrates (including uronic acids), 20% proteins, 9% moisture and 4.5% ash. The crude polysaccharides consisted of glucose (22.6%), rhamnose (10.0%), arabinose (7.9%), galactose (5.0%), xylose (0.8%) and galacturonic acid (11.8%).     

Optimization of culture parameters of selenium-enriched yeast (Saccharomyces cerevisiae) by response surface methodology (RSM)

Effect of culture conditions (temperature, initial pH value and volume) on the bioaccumulation of selenium (Se) in yeast (Saccharomyces cerevisiae) were investigated by response surface methodology (RSM) in this paper. The combined effects of culture conditions on Se yield were studied using a three-level three-factor Box-Behnken design. Fermentation was carried out at different temperature (24-32 °C), initial pH value (4-7) and volume (40-100 mL). The results showed that the optimum conditions for Se enrichment of yeast were found at temperature 27.4 °C, initial pH value 5.8 and volume 89.4 mL. Total Se yield was significantly affected by culture temperature (P < 0.05), initial pH value (P < 0.01) and volume (P < 0.01).Using a culture medium supplemented with 15 μg/mL sodium selenite (Na₂SeO₃) added at 9 h after inoculation which is the logarithmic growth phase, the maximum biomass and total Se yield in yeast could reach 9.23 g/L and 5.90 mg/L, respectively, which were significantly higher (P < 0.05) than that of the control (8.82 g/L and 4.31 mg/L)     

Aqueous extraction kinetics of phenolic compounds from jamun (Syzygium cumini L.) seeds

In this study, aqueous extraction of phenolic compounds from jamun (Syzygium cumini L.) seed was undertaken. The effects of various parameters such as extraction temperature (34.8–85.2°C), extraction time (49.8–100.2 min), and liquid-to-solid ratio (9.8–60.2 mL/g) on the extraction yield, extract purity (i.e., total polyphenol content), and its antioxidant activities (1,1-diphenyl-2-picrlthydrazyl free radical scavenging assay and ferric reducing antioxidant power) were investigated. Response surface methodology was used to optimize the extraction conditions. The optimum extraction conditions (49.2°C, 89.4 min, and 51.6:1 mL/g) produced an extract with 17.3% extraction yield, high total polyphenol content (415 mg gallic acid equivalent/g dried extract) and significant antioxidant activity (IC₅₀: 35.4 ± 0.7 µg/mL). The high-performance liquid chromatography analysis of seed extract revealed the presence of gallic acid (90.8 mg/g dried extract), ellagic acid (36 mg/g dried extract), caffeic acid (26.07 mg/g dried extract), p-coumaric acid (0.26 mg/g dried extract), catechin (9.05 mg/g dried extract), epicatechin (0.42 mg/g dried extract), and quercetin (1.54 mg/g dried extract). Tannic acid (188.5 mg/g dried extract) was also identified as a major phenolic compound. The extraction kinetics was also studied and experimental data were fitted to four kinetic models such as first-order model, second-order model, Peleg’s model, and Minchev and Minkov model, to evaluate their applicability.     

响应面法优化玉米黄粉中玉米黄素和玉米醇溶蛋白的提取工艺

采用响应面法同时优化了玉米黄粉中醇溶蛋白和玉米黄素的提取工艺。在单因素实验基础上,选取乙醇体积分数、提取温度、提取时间为影响因子,以玉米黄素和玉米醇溶蛋白质量为响应值,应用Box-behnken中心组合试验设计建立数学模型,进行响应面分析。得到提取的最优工艺条件为乙醇体积分数83.36%、提取温度62.13℃、提取时间5.79h,此条件下玉米黄素质量为420.1μg,而玉米醇溶蛋白质量为0.6165g。与响应面所得理论值418.9μg和0.6153g十分接近,玉米黄素得率和玉米醇溶蛋白提取率分别达到0.021%、79.03%。该研究为工业化提供了依据。     

Concentration of phenolic compounds in aqueous mate (Ilex paraguariensis A. St. Hil) extract through nanofiltration

In order to establish the parameters to obtain aqueous mate extract with the highest content of total phenolic compounds (TPC), the response surface methodology (RSM) was used. The extract obtained at 100 °C, within 3 min and with pH of 6.0 was submitted to nanofiltration to concentrate the phenolic compounds of mate (Ilex paraguariensis A. St. Hill). The total phenolic content values in the permeate and in the concentrate collected in different volumetric reduction factors (VRF) were different from those detected in the feed extract. The concentration of phenolic compounds increased when VRF was increased, reaching the highest retention index (R) of 0.99 when VRF was 4.0. The permeate and the concentrate obtained in VRF 4.0 were verified through HPLC. 4,5-dicaffeoylquinic acid and gallic acid showed retention index of 1.00 and 0.95, respectively, while 3,4-dihydroxybenzoic acid and chlorogenic acid reached 0.99 and 0.98, respectively.     

Response surface methodology for protein extraction optimization of red pepper seed (Capsicum frutescens)

Response surface methodology was used to determine optimum conditions for extraction of protein from red pepper seed meal. A central composite design including independent variables such as temperature (30, 35, 40, 45 and 50 °C), pH (7.0, 7.5, 8.0, 8.5 and 9.0), extraction time (20, 30, 40, 50 and 60 min) and solvent/meal ratio (10:1, 15:1, 20:1, 25:1 and 30:1 v/w) was used. Selected response (dependent variable) which evaluates the extraction process was protein yield and the second-order model obtained for protein yield revealed coefficient of determination of 96.7%. Protein yield was primarily affected by pH and solvent/meal ratio. Maximum yield was obtained when temperature, pH, mixing time and solvent/meal ratio were 31 °C, 8.8, 20 min, 21:1 (v/w), respectively. These conditions resulted in protein yield of 12.24 g of soluble protein from extract/100 g defatted red pepper seed flour. The adequacy of the model was confirmed by extracting the protein under optimum values given by the model. These results help in designing the process of optimal protein extraction from red pepper seeds.     

Response surface methodology for optimization of extraction yield, viscosity, hue and emulsion stability of mucilage extracted from Lepidium perfoliatum seeds

Response surface methodology was used to determine the optimum processing conditions that give maximum extraction yield, viscosity, hue and emulsion stability, as well as, minimum protein content for the gum extracted from Lepidium perfoliatum seed. Temperature (45–75 °C), processing time (1.5–3.5h), pH (5–8) and water to seed ratio (30:1–60:1) were the factors investigated. Experiments were designed according to Central Composite Rotatable Design with these four factors, including central and axial points. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Applying desirability function method, optimum operating conditions were found to be extraction temperature of 48.1 °C, pH of 8, water to seed ratio of 30:1 and process time of 1.5 h. At this optimum point, extraction yield, viscosity, protein content, hue and emulsion stability were found to be 17.36%, 463.07 mPa s, 2.84%, 60.47 and 88.96 %, respectively.     

Formulation of pasta from rice brokens: optimization of ingredient levels using response surface methodology

Rice brokens were utilized in the development of pasta products. Response surface methodology was used to analyze the effect of pregelatinized rice flour (from rice brokens), vital gluten, water, glycerol monostearate (GMS) and carboxy methyl cellulose (CMC) on the quality responses (sensory, cooking quality, rehydration ratio and solids loss) of the pasta product. A rotatable central-composite design was used to develop models for the responses. Responses were affected most by changes in rice flour and vital gluten levels and to a lesser extent by water, GMS and CMC levels. The maximum sensory score, cooking quality, rehydration ratio and minimum solids loss were identified at 682.54 g/kg rice flour, 235.85 g/kg water, 70.70 g/kg vital gluten, 1.59 g/kg GMS and 9.33 g/kg CMC level.     

Optimization of the extraction of flavanols and anthocyanins from the fruit pulp of Euterpe edulis using the response surface methodology

The response surface methodology (RSM) was employed to optimize the ultrasound extraction of flavanols and anthocyanins from the pulp of jussara (Euterpe edulis), using a second-order polynomial equation to describe the experimental data for total flavanol (TF), total phenolic (TP), and total monomeric anthocyanin (TMA) contents, as well as the total antioxidant activity (TAA). A central composite design with two-variables (extraction time and solid to liquid ratio) was then applied. The optimized conditions that maximized the yields of flavanol-enriched extract were a solvent methanol/0.1 M HCl, solid to liquid ratio of between 1:50 and 1:100 and extraction time of 15 min. For anthocyanin-enriched extracts the respective optimal parameters were a solvent methanol/1.5 M HCl, solid to liquid ratio of between 1:30 and 1:50 and extraction time of 24 h. The results showed good fits with the proposed model for both the flavanol-enriched extract (R² = 0.94) and for the anthocyanin-enriched extract (R² = 0.99).     

响应面法优化木瓜蛋白酶提取草鱼鱼鳞胶原蛋白的研究

以草鱼鱼鳞为原料,用木瓜蛋白酶解提取草鱼鱼鳞中的胶原蛋白,并对其性质进行初步研究。在单因素试验的基础上,采用响应面法Box-Behnken试验设计,对影响提取率的酶解温度、加酶量、底物质量分数3个因素进行优化,建立并分析各因素与胶原蛋白提取率关系的数学模型。确定木瓜蛋白酶提取鱼鳞胶原蛋白的最佳条件为酶解温度50℃,加酶量3.5g/L,底物质量分数22%,经过验证胶原蛋白提取率为15.4%。得到鱼鳞胶原蛋白吸水性接近于甘油,保水性优于甘油,具有一定的乳化性和乳化稳定性。     

Response surface methodology for optimisation of protein concentratepreparation from cowpea [Vigna unguiculata (L.) Walp]

The optimum conditions for the preparation of protein concentrate from cowpea were determined using response surface methodology. A central composite rotatable design, consisting of eight experimental points and five replications at the centre point, was used to investigate the effects of two independent variables, namely pH and NaCl concentration on four responses: protein content (%,), protein yield (%), reactive lysine (g/16 g N) and zinc content (mg/100 g). A second-order polynomial model was used for predicting the responses. Regression analysis indicated that more than 80% of the variation was explained by the fitted models. Experimental results showed that under optimum conditions (pH and NaCl concentration of 9.91 and 0.15 M, respectively) the protein content was 84%, protein yield 87%, reactive lysine 1.175 g/16 g N and zinc content 7.75 mg/100 g. These results were in agreement with those predicted, hence indicating the suitability of the model used.     

响应面法优化高压脉冲电场提取沙棘果皮渣黄酮

沙棘黄酮具有抗氧化、抗菌消炎、降血脂等多种药理作用。以沙棘果皮渣为原料,以沙棘黄酮提取率为指标,采用高压脉冲电场辅助提取沙棘果皮渣中的黄酮类化合物,在单因素实验基础上采用响应曲面法考察了高压脉冲电场强度、脉冲数和料液比村沙棘黄酮提取率的影响。结果表明,沙棘黄酮最优提取条件为：电场强度20kV／cm、脉冲数10、料液LLI：15,此时黄酮得率为10．23mg／g,比碱提酸沉法和超声波法提取率分别提高了42％和19％。通过网归方程求解和响应曲面分析,得到了二次多项式提取回归模型,经验证实验值与模犁预测值拟合性良好。     

Partial characterization of white cabbages (Brassica oleracea var. capitata f. alba) from different regions by glucosinolates, bioactive compounds, total antioxidant activities and proteins

Glucosinolates (GLS), antioxidative compounds, total radical scavenging activities (TRSAs) and proteins of white cabbage samples derived from different regions of Europe, collected in the spring and autumn, were studied. Glucobrassicin and sinigrin were the dominating GLS in all analyzed cabbage samples. Depending on origin, these two GLS accounted for ∼30% to ∼70% of the total. The total GLS content ranged from 3.3 to 7.7 μmol/g dw in lyophilized vegetables. Assays based on electron transfer [total phenols by Folin-Ciocalteu reagent (FCR), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] radical cation (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH)] were used to compare the TRSAs and the main bioactive compounds in cabbage. Total polyphenols varied from 2.4 to 4.9 GAE/g dw. The TRSAs ranged from 2.7 to 8.2 μmol TE/g dw in ABTS test and from 2.4 to 5.4 μmol TE/g dw in DPPH assay. The maximum amount of polyphenol compounds, antioxidant activity, as well as total GLS content, were recorded in Belgian cabbage harvested in the autumn and the lowest ones were found for Poland 2 cabbage harvested in the spring. In extracted and separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) proteins from cabbage leaves only in samples from England and Belgium some differences in patterns were found in the regions of 60 and 97 kDa. The calculated correlations between antioxidative potency and the abundance of bioactive compounds were highly statistically significant. This suggests that TRSA could serve as a means of standardization of natural mixtures, at least in the case of cabbage, necessary to compare results of biological studies carried out for vegetable derived samples.