Large-scale extraction of rhamnogalacturonan I from industrial potato waste

Potato pulp is rich in dietary fibres and is an underutilised material produced in large quantities by the potato starch factories. Potato fibres are especially rich in rhamnogalacturonan I (RG I). RG I is a pectic polysaccharide with a high degree of branching and until now undegraded RG I has only been extracted in small amounts limiting the application possibilities for RG I. The present paper describes a large-scale extraction process providing large quantities of undegraded RG I readily available. The extraction process includes enzymatic starch removal using purified Termamyl, enzymatic RG I solubilisation using a highly purified polygalacturonase, and finally purification using depth filtration and ultrafiltration. The extracted RG I has a high molecular weight and a monosaccharide composition comparable to RG I extracted by analytical extraction procedures. The large amount of RG I available by the presented method allows for thorough structure-function analyses and tailoring of RG I to specific functionalities.     

酶解-超声协同提取茄蒂多糖及抗氧化研究

以茄蒂为原料,研究了酶解超声协同提取茄蒂多糖条件及抗氧化能力。在pH5、50℃水浴温度下用1%纤维素酶酶解30min,采用响应面法优化超声提取茄蒂多糖条件。通过测定对羟自由基、超氧自由基清除能力和总还原力,评价茄蒂多糖抗氧化活性。结果表明,茄蒂多糖最佳提取条件为:料液比1∶36(g/mL),超声时间22min,超声温度68℃。在此条件下多糖得率为5.49%。茄蒂多糖对羟自由基、超氧自由基清除能力和还原力均表现较好的效果,其清除羟自由基、超氧自由基的IC50值分别为0.12、0.22mg/mL。茄蒂多糖抗氧化性略低于VC。      

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 microwave frying of osmotically dehydrated potato slices by using response surface methodology

Microwave frying of osmotically dehydrated potatoes was optimized by using response surface methodology. Osmotic dehydration was applied prior to microwave frying in order to reduce oil uptake and to evaluate the effect of osmotic dehydration on quality of microwave fried potatoes. Moisture content, oil content, hardness and color of the fried potatoes were used as quality parameters. Microwave power level (400, 550, 700 W), frying time (1.5, 2.0, 2.5 min) and osmotic dehydration time (15, 30, 45 min) were the independent variables in the study. Osmotic dehydration treatment was conducted using 20% (w/w) sodium chloride solution at 30 °C. Moisture content of the fried potatoes decreased whereas oil content, hardness and ΔE value of potatoes increased with increasing frying time and microwave power level. The increase in osmotic dehydration time reduced moisture content and oil content and increased hardness of fried potatoes. The optimum condition was found as frying at 400 W microwave power level for 1.5 min after 39 min of osmotic dehydration time.     

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).     

Role of pectic polysaccharides in structural integrity of apple cell wall material

Texture modulating properties of aqueous dispersions of apple cell wall material differed from those of tomato or kiwifruit, particularly under high shear. It was previously hypothesized that this may be due to the fact that the apple cell wall showed less in vivo solubilization of pectic polysaccharides during ripening compared to tomato or kiwifruit. However, in vitro solubilization of the pectic polysaccharide content of apple CWM by endo-polygalacturonase and/or extraction with 0.05 M sodium carbonate, did not affect the loss in wall integrity shown by tomato or kiwifruit CWMs under shear. In addition, the pectin-depleted residue after Na₂CO₃ extraction possessed better water retaining and viscosity generating properties than the original cell wall material. Following treatment of apple CWM with cellulase, the viscosity of suspensions decreased, emphasising the role that the cellulose–hemicellulose network plays in the water-retaining capacity of the cell wall. Residue from CWM after cellulase treatment consisted of ∼85% pectic polysaccharides. Surprisingly, the integrity of these “cellulose-free” walls was maintained after shear. It is concluded that differences in structural properties of the CWMs of apple compared to kiwifruit or tomato are not simply related to pectin solubilization but to a fundamental difference in the architecture of the apple cell wall.     

Response surface methodology for optimisation of soluble dietary fibre extraction from sweet potato residue modified by steam explosion

To make better use of sweet potato residue (SPR), a new pretreatment method, steam explosion (SE), can increase its content of soluble dietary fibre (SDF). Response surface methodology (RSM) was used to determine the SE variables for optimum SDF yield. The optimal conditions were a steam pressure of 0.35 MPa, a residence time of 121 s and a sieving mesh size 60. Under the optimised conditions, the content of SDF from SPR reached 22.59 ± 0.35%, an increase of 18.78% compared with that (3.81 ± 0.62%) from untreated SPR. The water‐holding capacity, oil‐holding capacity (OHC) and swelling capacity of SDF were improved by SE. Scanning electron micrograph (SEM) images demonstrated that SDF had become poriferous, loose and dilatants after SE treatment. This technology provides an efficient process for increasing the industrial production of SDF from SPR.     

The optimisation of extraction of antioxidants from potato peel by pressurised liquids

Response Surface Methodology was used to optimise the solid–liquid extraction and Pressurised Liquid Extraction of polyphenols from industrially generated potato peel. Efficiency of extraction was optimised by measuring antioxidant activity, phenol content and the level of caffeic acid. Conditions for optimal antioxidant activity as measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were 75% ethanol, 80 °C and 22 min with solid–liquid extraction, resulting in an optimum activity of 352 mg Trolox Equivalents/100 g DW potato peel. In comparison, the use of Pressurised Liquid Extraction resulted in an optimum activity of 339 mg Trolox Equivalents/100 g DW potato peel at 70% ethanol and 125 °C. Therefore the use of Pressurised Liquid Extraction did not enhance extraction in comparison to solid–liquid extracts, but using aqueous ethanol as extraction solvent recovered a higher level of polyphenols than when using 100% methanol.     

Effect of formulation and processing parameters on acrylamide formation: A case study on extrusion of blends of potato flour and semolina

Acrylamide formation in extruded snacks prepared using blends of potato flour:semolina in ratios ranging from 30:70 to 70:30 showed maximum acrylamide formation in the 70:30 blend. The extrusion was carried out at a screw speed of 120 rpm, temperature of 170 °C and moisture content of 18%. Further, the influence of extrusion processing parameters on the acrylamide formation in extruded snacks prepared from a 70:30 blend of potato flour:semolina was investigated using response surface methodology (RSM). The feed moisture was varied from 12.6% to 19.4%, die temperature from 163 to 197 °C and screw speed from 106 to 173 rpm. The extrudates so obtained showed acrylamide content ranging from 704 to 1560 μg/kg. The effect of different additives such as citric acid, calcium salts, amino acids, vitamins and their combinations on the mitigation of acrylamide formation showed calcium chloride at 50 μmol/g flour blend to reduce acrylamide formation by 65% without altering the sensory properties of the extrudates.     

Optimization of stepwise blanching of frozen-thawed potato tissues (cv. Monalisa)

 Response surface methodology was used to compare the effect of temperature and time of the first step of blanching on compression, shear, tension and stress-relaxation parameters of frozen-thawed potato tissues. A central, composite rotatable design was used to study the effects of variation in levels of temperature (52.93–67.07  °C) and time (15.86–44.14 min) on rheological parameters. Blanching temperature was the most important factor affecting the mechanical properties tested. The models fitted for the apparent modulus of elasticity in compression, maximum tension force, and relaxed force in the first cycle (F _r1); all had R ²>0.85 (P≤0.01) and were used for doing predictions. Optimum conditions were with in the ranges of temperature (60–65  °C) and time (25–35 min) used for each factor. In the experimental verification of the models at 65  °C during 30 min, the lowest percentage residual between experimental and predicted values was obtained for F _r1 (0.644), which was therefore the most appropiate parameter for detecting the firming effect that the pectinesterase activity produced on frozen potato tissues as a consequence of stepwise blanching under these conditions. Received: 3 February 1999 / Revised version: 12 April 1999     

酶法辅助提取红松种壳多酚的工艺优化研究

利用在乙醇提取红松种壳提取多酚物质工艺中加入纤维素酶酶解工艺,以提高多酚得率。通过单因素实验,研究了乙醇浓度、酶解时间、料液比、酶解温度、加酶量、pH对红松种壳中提取多酚得率的影响。并在单因素实验基础上,设计六因素五水平的Small Composite:Hartley Method中心组合实验及响应面法分析对红松种壳中多酚的提取工艺进行优化,建立了二次多项式回归方程的预测模型,结果表明,提取红松种壳多酚的最佳工艺为:乙醇浓度61%、酶解时间2h、液料比36∶1、酶解温度62℃、加酶量106U/g、pH4.6。在此工艺条件下,红松壳多酚得率可达8.93mg/g。在乙醇提取红松壳多酚工艺中,采用纤维素酶预先进行酶解可以增加多酚得率,增加量为0.97mg/g。      

响应面分析法优化向日葵盘中果胶的提取工艺研究

通过响应面分析法对向日葵盘果胶的提取工艺进行优化.利用响应面实验设计考察提取温度、提取时间、料液比和pH值4因素对果胶提取量的影响.研究发现：提取时间、温度和pH值对提取量有显著影响,向日葵盘果胶的最佳提取条件是：提取温度为79℃、提取时间为80 min、料液比25∶1、pH值3.20;每5 g向日葵盘中果胶最大提取量为0.522 g.     

Optimization of the blanching process to reduce acrylamide in fried potatoes

A central composite design was used to study the effect of blanching time and temperature on the extraction of reducing sugars from potato strips and slices. After frying, the impact of both factors on the acrylamide content in French fries and potato crisps was evaluated. Acrylamide could be lowered more efficiently in potato crisps compared to French fries, due to a more pronounced extraction of sugars from potato slices upon blanching. In both products, blanching temperature was the main influencing factor for sugar extraction and subsequent acrylamide mitigation. Blanching at temperatures of about 70 °C for a short period of time (about 10 min) was more efficient compared to blanching at lower temperatures, which appeared more time-consuming. However, the extraction efficiency of reducing sugars was over 10% lower when the potato cuts were blanched in water which was previously used for blanching, leading to over 10% less reduction in the final acrylamide content.     

双水相体系萃取蓝莓多糖的分配平衡研究

采用超声水提法提取蓝莓多糖,再用双水相法进行纯化。以药液百分数、K₂HPO₄浓度、PEG6000浓度为单因素,以下相多糖的萃取率为指标,应用响应面法优化蓝莓多糖的双水相萃取工艺。结果表明,当药液百分数60%,PEG6000 16%,K₂HPO₄ 16.9%,下相蓝莓多糖得率最高,可达95.03%;且多糖纯度明显高于传统的水提醇沉法。所得到模型高度显著（R²=0.9920）,拟合性好,可用于蓝莓多糖的萃取。      

五味子多糖超声波提取条件的研究

在单因素实验的基础上,利用响应曲面法(response surface methodology,RSM),通过中心组合设计,对超声波前处理提取五味子多糖的工艺参数进行优化分析研究。选择处理时间、处理温度和超声功率作为优化因素,研究了各因素对五味子多糖得率的影响。通过分析得到多糖的提取优化条件:处理时间70min,处理温度30℃;超声功率300W。在这个条件下,五味子多糖的提取率为16.729%±0.248%,与热水浸提法相比,提取率提高了50%。     

响应面法优化玉米苞叶多糖的提取工艺

应用响应面法优化玉米苞叶多糖提取工艺。单因素实验基础上,选择提取时间、提取温度、液料比、乙醇浓度为影响因子,多糖提取率为响应值,利用Box-Behnken中心组合设计建立数学模型,进行响应面分析。研究结果显示:玉米苞叶多糖的最佳提取工艺为:提取时间2.0 h、温度83℃、液料比17∶1（m L/g）、乙醇浓度63%,此条件下的多糖提取率为0.552%。      

茶树花多糖超声波辅助热水浸提工艺优化

利用响应曲面法优化超声波辅助热水浸提技术提取茶树花多糖工艺。在单因素实验的基础上,通过Central Composition Design建立多糖提取率与超声时间、超声功率和液料比之间的数学模型,确定最优提取工艺参数。结果表明,最优工艺条件为:超声时间12min,超声功率540W,液料比30∶1m L/g,在此条件下茶树花多糖提取率为7.69%。该方法实用、可靠,可用于茶树花多糖的提取。      

响应面法优化海地瓜皂苷提取工艺

目的:以海地瓜为原料,开展了海地瓜皂苷的提取工艺研究。方法:在单因素分析的基础上,采用了响应面法分析了乙醇浓度、料液比、提取温度、提取时间等因素对海参皂苷得率的影响,优化获得最佳的海地瓜皂苷提取工艺为:乙醇浓度为79%,提取温度为73.5℃,提取时间为2.75 h,料液比为1∶1.7 g/m L。对海地瓜皂苷的影响由大到小依次为乙醇体积、乙醇浓度、提取时间和提取温度。在该工艺下提取海地瓜皂苷得率为0.378%。与模型预测值一致。结论:响应面分析法确定的提取条件合理,验证值与预测值接近,可以用于海地瓜皂苷的提取工艺优化。      

响应面法优化羊肚菌多糖的提取工艺

针对羊肚菌多糖的提取,通过单因素实验,根据Box-Benhnken的中心组合实验设计原理,采用3因素3水平的响应面分析法,确定各工艺条件的影响因子,以羊肚菌多糖提取率为响应值作响应面和等高线图。结果表明,羊肚菌多糖水浸提的最佳工艺条件为提取温度85.03℃,浸提时间147.75min,水料比30.58:1,浸提1次时,羊肚菌多糖的提取率为5.305%。     

响应面法优化水提菜籽多糖工艺

研究了从菜籽粕中水提菜籽多糖的工艺。在单因素试验的基础上,以提取温度、提取时间与料液比为因素,以菜籽多糖得率为指标,采用响应面法优化菜籽多糖的提取工艺。结果表明:在提取温度80℃、提取时间3.4 h、料液比1∶34、提取1次的条件下,菜籽多糖得率为2.09%。