响应面方法在优化β-胡萝卜素培养基的应用

多种统计优化方法已被成功地运用于微生物培养基优化工作中,本文根据响应面分析法的基本原理,针对响应面方法的优点、试验设计的方法以及实验数据的处理进行了简述,并结合三孢布拉霉发酵生产β-胡萝卜素培养基成分的确定说明了响应面方法的具体应用.     

响应面法优化康宁木霉产纤维素酶的发酵培养基

采用响应面法对康宁木霉产纤维素酶的发酵条件进行了优化。首先运用Plackett-Burman法筛选出3个影响较大的重要因素,分别为:葡萄糖,MgSO4.7H2O,MnSO4.H2O。然后进行最陡爬坡实验,确定这3种重要因素的最适质量浓度范围。最后通过Box-Behnken设计,利用Design Expert软件进行回归分析,得出3种因素的交互作用及最佳发酵条件。确定康宁木霉发酵产纤维素酶的最佳发酵培养基为葡萄糖5.97 g/L,乳清粉7 g/L,玉米浆干粉13 g/L,(NH4)2SO4 4 g/L,KH2PO4 8 g/L,MgSO.4 7H2O 0.56 g/L,CaCl.2 2H2O 0.6 g/L,FeSO.4 7H2O 2.5 mg/L,ZnSO4.7H2O 0.7 mg/L,CoCl.2 6H2O 1.9 mg/L,MnSO.4 H2O 4.07 mg/L,吐温-80 1.5 mL/L,在此培养基下发酵酶活为0.233 IU/mL,比优化前提高了35.7%。     

响应面法优化绿色木霉产壳聚糖酶培养基

利用响应面(RSM)方法对绿色木霉液体发酵产壳聚糖酶的培养基进行优化。根据前期单因素实验结果,确定Avicel、玉米芯和棉籽饼粉为主要影响因素,利用Design Expert 7.1.3软件对RSM法实验结果进行了优化,获得了最佳产酶培养基为:Avicel2.56%、玉米芯1.03%、麸皮0.5%、棉籽饼粉4.79%、KH2PO40.2%、(NH4)2SO40.2%、CaCl20.03%、MgSO40.03%,pH自然,此时预测的最大壳聚糖酶活为2.13IU/mL。经验证,实测的壳聚糖酶活为2.00IU/mL,实际酶活力达理论预测值的94%。同时测定了羧甲基纤维素酶活(CMCase),发现CMCase酶活越大,壳聚糖酶活也越大,CMCase酶活与壳聚糖酶活平均比值为110.88,两种酶活呈正相关性。      

响应面法优化里氏木霉Rut C-30产纤维素酶液体培养基

该试验在单因素对里氏木霉(Trichoderma reesei)Rut C-30产纤维素酶的液体培养基优化的基础上,以滤纸酶活为响应值,采用响应面法确定其最佳培养基。首先通过Plackett-Burman(PB)设计筛选出影响滤纸酶活的显著因素,结晶纤维素和麸皮;通过最陡爬坡试验逼近最大酶活力区域;最后通过Central Composite Design(CCD)设计及响应面分析确定产酶最佳培养基,其中影响酶活的显著性因素结晶纤维素41.8g,麸皮19.1g。经过优化,滤纸酶活力最高为8.21U/mL,比单因素优化结果7.03U/mL提高了16.78%,同时测得CMC酶活为63.64IU/mL,木聚糖酶活为27.4IU/mL,葡萄糖苷酶酶活0.96IU/mL。     

响应面法优化康宁木霉产纤维素酶固态发酵培养基

采用响应面法试验设计,对康宁木霉(Trichoderma konigii)固态发酵玉米皮生产纤维素酶的条件进行了优化,并建立了纤维素酶随麸皮添加量、物料初始水分质量分数和pH值变化的二次回归方程。利用该方程探讨了各因子对纤维素酶的影响。结果表明,各因子对纤维素酶的影响顺序为:物料初始水分质量分数>麸皮添加量>pH值,各因子间交互作用不显著。结合单因素实验,最终确定适宜的发酵条件为:麸皮添加量24.4 g/dL;营养液添加量:1.0 g/dL硫酸铵,0.05 g/dL磷酸二氢钾,0.1 g/dL硫酸镁,0.2 g/dL乳糖;初始水分质量分数58.6%;pH 5.5。在此条件下发酵120 h,滤纸酶活达到11.3 IU/g,较未优化前提高了2.9倍。     

响应面法优化油茶粕培养里氏木霉酶系活力条件及发酵工艺研究

以油茶粕为底物,对里氏木霉发酵进行培养,研究了油茶粕比例、微晶纤维素添加量、接种量和pH对里氏木霉纤维素酶活力的影响。在单因素实验的基础上,采用响应面分析,优化发酵条件为:油茶粕比例为8. 6%,微晶纤维素添加量为0. 93%,接种量为12. 48%,pH值为4. 9。在该条件下,羧甲基纤维素酶活力为8. 47 U/mL,微晶纤维素酶活力为9. 28 U/mL,纤维二糖酶活力为5. 05 U/mL,滤纸酶活力为5. 44 U/mL。     

响应面法优化小球藻培养基

为了提高小球藻的生物量,对BG11培养基的成分进行了响应面优化。通过单因素实验筛选出了适合小球藻生长的最佳碳源、氮源分别为葡萄糖和尿素,并发现适量添加海绿素可显著促进小球藻的生长。利用Minitab软件设计Plackett-Burman实验筛选出了影响小球藻生长的三个最重要因子;通过Box-Behnken实验及响应面分析确定了三个因子的最佳浓度:磷酸氢二钾58mg/L,硫酸镁162mg/L,海绿素198μL/L。用优化后的培养基培养小球藻,48h后的藻细胞干重达10.09g/L,比优化前提高了61.2%,油脂及蛋白质产量分别达3.62和3.81g/L。     

利用响应面法优化GSH发酵培养基

利用Plackett-Burman试验设计,筛选出影响GSH产量的3个重要因素,分别为葡萄糖、蛋白胨、KH2PO4.在此基础上,再利用Box-Behnken试验设计及借助于MINTAB软件进行二次回归分析,确定了主要影响因素的最佳浓度,葡萄糖、蛋白胨、KH2PO4最佳发酵质量浓度分别为2.75%、3.03%、0.11%.在优化的培养基中,GSH产量达到147.02mg/L,比优化前的98.94mg/L提高48.60%.     

响应面法优化纳豆激酶发酵培养基

纳豆激酶具有良好的溶解血栓的功效,由于纳豆激酶目前的发酵水平不高,限制了其应用。该研究以纳豆激酶活力为响应值,在单因素试验基础上,采用Plackett-Burman试验、最陡爬坡试验和响应面法对纳豆激酶培养基配方进行了优化。结果表明,通过Plackett-Burman试验筛选出豆粕粉、无水氯化钙、甘油为影响纳豆激酶活力的主要因素。最后运用响应面分析确定纳豆激酶最优发酵培养基为：甘油43 g/L、豆粕粉24 g/L、无水氯化钙0.14 g/L、七水硫酸镁0.80 g/L、十二水磷酸氢二钠3.00 g/L、无水磷酸二氢钾1.00 g/L、L-甲硫氨酸0.20 g/L,此条件下纳豆激酶活力最高为（4 281±103）FU/mL,是优化前的1.97倍。     

应用响应面法优化叶黄素降解发酵培养基

利用响应面分析法对Pantoea dispersa（Y08）菌降解叶黄素产香的培养基进行了优化。采用Box-Behnken实验设计,选定KH2PO4、蔗糖和混合氮源（酵母膏∶天门冬酰胺=2∶1）3个关键因子为响应因子,以叶黄素降解率为响应值建立多元二次回归方程,在分析各个因素的显著性和交互作用后,确定了Pantoea dispersa菌降解叶黄素的最优培养基为:蔗糖0.97%,混合氮源（酵母膏∶天门冬酰胺=2∶1）1.38%,KH2PO40.15%,叶黄素降解率为80.03%,与理论预测值基本吻合,比优化前提高140.67%。      

APPLICATION OF RESPONSE SURFACE METHODOLOGY FOR THE OSMOTIC DEHYDRATION OF CARROTS

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.     

OPTIMIZATION OF NATTOKINASE PRODUCTION CONDUCTION USING RESPONSE SURFACE METHODOLOGY

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.     

响应面法优化灰树花中多糖超声波提取工艺的研究

通过响应面法分析优化了超声提取灰树花中多糖的工艺条件,并与传统水提法进行了比较分析.结果表明,超声提取灰树花中多糖的最佳工艺条件为:提取时间171 s,提取功率352.4 W,液料比47.9:1(mL:g),提取率预测值为14.23%,验证值为14.26%,与预测值的相对误差为0.21%,多糖得率比传统水提法有所提高,且提取时间大大减少.     

OPTIMIZATION OF ONION COOKIE BAKING PROCESS USING RESPONSE SURFACE METHODOLOGY

ABSTRACT

Response surface methodology (RSM) was used for the optimization of the baking process of cookies made by substituting onion powders (onion cookie). The experiments were carried out according to a central composite design, selecting onion powder content and baking time as independent variables, and pH, titratable acidity, moisture content, density, spread factor, Commission Internationale de I'Eclairage (CIE) color parameters (L*, a*and b*values), hardness and maximum deflection as response variables. Most polynomial models developed by RSM were highly effective to describe the relationships between the studied factors and the responses. Overall optimization, conducted by overlaying the contour plots under investigation, was able to point out an optimal range of the independent variables within which the eight responses were simultaneously optimized. The point chosen as representative of this optimal area corresponded to onion powder content = 2.5% and baking time = 13.61 min, conditions under which the model predicted pH = 7.10, titratable acidity = 117.08 g acid/100 g, moisture content = 3.21%, spread factor = 6.87, L*value = 71.40, a*value = 0.21, b*value = 31.69 and maximum deflection = 2.62 mm.

PRACTICAL APPLICATIONS

Response surface methodology (RSM) was successfully applied to optimize the cookie baking process. Most polynomial models developed by RSM were highly effective to describe the relationships between the studied factors and the responses. This method provided a simple and straightforward optimization analysis for cookie baking, and the results would help to develop a new value‐added functional food containing onion powder, which is readily available and an inexpensive source of antioxidant properties. Onion powder is known to be a better ingredient than onion extract in the formulation of value‐ or function‐added products. The results can be easily implemented to estimate the physicochemical properties when the process parameters are known.

     

OPTIMIZATION OF MANUFACTURE OF ALMOND PASTE COOKIES USING RESPONSE SURFACE METHODOLOGY

The response surface methodology (RSM) was used in the optimization of a modified recipe of almond paste cookies to pinpoint the best combination of the most important factors, in order to obtain an enhanced product with quality characteristics similar to the typical one. In this modified recipe, bamboo fiber and fructose were added as humectant and anticrystallizing agents to extend the shelf life of the cookies. Five quantitative controllable factors were selected for the experimental design: weight of bamboo fiber, fructose/saccharose ratio (F/S) and weight of egg white as ingredients, and baking time and temperature as process parameters. To assess the product quality, texture, moisture content and color were considered as dependent variables. The three second-order polynomial models obtained by RSM and the subsequent optimization step indicated that a formulation with 28.95 g of fiber, 252.5 g of egg white, an F/S equal to 0.1, baking time and temperature of 21.5 min and 185.5C, respectively, represents the best recipe to manufacture a new product with quality attributes very similar to the typical one and, in addition, with an extended shelf life.

PRACTICAL APPLICATIONS

The importance of this work arises from the possibility to obtain new formulations by the enhancement of original recipes of products with a very limited shelf life using a statistical and designed approach. The achieved results led to a higher quality of these products over time, without changing the most important characteristics related to consumer acceptance.     

OPTIMIZATION OF CHEMICAL TRANSESTERIFICATION OF PALM OIL USING RESPONSE SURFACE METHODOLOGY

The effect of catalyst concentration (0.1–0.5% methoxide powder), temperature (50–92C), and time (30–480 min) of chemical transesterification was studied to determine the optimum condition for maximizing concentration of triunsaturated and trisaturated triacylglycerols (TG) in palm oil. TG compositions of the oil were analysed using high-performance liquid chromatography. The optimum condition of the process was determined using statistical response surface methodology. The results showed that the triunsaturated and trisaturated TG responses followed a second order form of the treatments with R²= 0.83 and 0.85, respectively. The triunsaturated TG reached a maximum concentration by using 0.36% catalyst at 78C and 360 min reaction time, whereas the trisaturated TG with 0.36% catalyst at 81C and 325 min reaction time. Considering the two responses, it was concluded that the overall optimum condition could be achieved at 0.36% of catalyst at 78–81C and 325–360 min reaction time. Such conditions increased trisaturated TG in palm oil by 2.34 times and triunsaturated TG by 1.54 times.