花椒多酚提取工艺响应面优化及动力学分析

以多酚收率为优化指标,对花椒中多酚的提取工艺进行研究,通过单因素试验考察处理温度、提取时间、溶剂体积分数、料液比和提取液pH值对多酚提取过程的影响。利用Box-Behnken响应面分析法优化多酚提取的最佳工艺条件为提取溶剂为乙醇溶液、溶剂体积分数48.23%、料液比1∶29.34（g/mL）、处理温度48.99?℃、提取时间1.75?h、提取液pH?3,在此条件下进行5?次平行实验,预测的多酚收率为55.06?mg/g。此外,研究不同温度下总酚的传质动力学,通过平板模型以Fick第一定律为基础建立了花椒多酚提取的动力学模型,并求解出速率常数、相对萃余率及活化能等关键模型参数,为花椒多酚提取的工厂放大和深入研究提供一定依据。     

银杏叶多酚超声辅助提取工艺及其对羟自由基的清除作用

以银杏叶为原料,采用超声辅助乙醇提取银杏叶多酚。在利用单因素试验对影响银杏叶多酚提取率的4个因素(乙醇浓度、料液比、提取温度和超声时间)考察基础上,以多酚提取率为响应值,采用Box-Behnken试验设计与优化,分析提取过程中工艺参数对提取率的影响,并以多酚对羟自由基的清除作用来衡量其抗氧化性。结果表明,银杏叶多酚的最佳提取工艺为:乙醇浓度74%、料液比1:25(g/mL)、提取温度62℃、超声时间30 min,在此条件下银杏叶多酚提取率为8.32%。所提取的银杏叶多酚对羟自由基的清除效果高于VC,且与浓度呈正相关。     

中心组合设计优化酶法辅助提取香菇多酚及其抑菌活性研究

为研究溶剂法提取香菇多酚的工艺条件,在考察提取温度、乙醇浓度、料液比及果胶酶添加量四个单因素对香菇多酚提取率影响的基础上,采用中心组合实验和二次多项式回归分析对提取工艺进行优化。实验结果表明香菇多酚的最佳提取工艺为:水浴温度85℃,提取剂乙醇浓度为50%,料液比1∶12(g∶mL),果胶酶添加量1.4%,在此条件下,香菇多酚的提取率为2.94%。此外,对香菇多酚采用琼脂平板扩散法进行抑菌实验,结果表明:香菇多酚对青霉菌和啤酒酵母菌无抑制效果,而对金黄色葡萄球菌和大肠杆菌均有抑制作用,且最低抑菌浓度为15mg/mL。      

梨幼果多酚提取工艺优化及其成分分析

采用正交实验对梨幼果果肉多酚物质提取工艺进行优化,并利用高效液相色谱法(HPLC)测定其多酚物质组成。结果表明,提取温度和乙醇浓度对梨幼果多酚得率影响较为显著,梨幼果多酚最佳提取工艺组合为:乙醇浓度60%,提取温度70℃,提取时间2h,提取料液比1∶30(g/mL),依照此工艺提取梨幼果多酚得率可达到1.47mg/g;从梨幼果中鉴定出熊果苷、表儿茶素、绿原酸、香草醛等9种酚类物质,其中熊果苷含量最高,为总含量的74.1%。      

滁菊活性成分的低温浸提及其对α-葡萄糖苷酶活性的抑制作用

为优化滁菊活性成分低温浸提工艺,以滁菊总多酚及总黄酮提取率为指标,考察时间、温度、液固比等因素对提取效果的影响,并采用正交实验优化浸提工艺。结果表明,滁菊低温浸提最佳工艺条件为:提取温度为60℃、液固比为30:1、浸提时间为50min,在此条件下,总多酚及总黄酮提取率分别为5.905、53.138mg/g。滁菊浸提液对α-葡萄糖苷酶活性具有抑制作用,IC₅₀为32μg/mL。      

多酚协同磷酸化对鸡肉蛋白功能及货架期研究

采用多酚(绿原酸、没食子酸)协同三聚磷酸钠(STP)对鸡肉肌原纤维蛋白(MP)进行修饰,考查对蛋白功能特性的影响。同时,研究在不同贮藏温度下,多酚协同磷酸化后的熟制鸡肉丸色差、pH值、菌落总数和感官评价随贮藏时间的变化,对货架期进行预测。结果表明:多酚的添加使乳化活性、乳化稳定性和浊度增大,表面疏水性减小;随多酚浓度的增大,乳化活性和乳化稳定性先增大后减小;低中浓度对表面疏水性、浊度影响不大;高浓度使表面疏水性显著减小,浊度显著增大。贮藏温度越高,鸡肉丸各指标变化速率越快;不同贮藏温度下鸡肉丸的菌落总数变化符合一级反应,反应速率常数符合Arrhenius方程,建立货架期动力学模型,对其验证发现模型拟合度良好,能预测鸡肉丸不同温度下的货架期寿命。     

超声协同双水相体系提取路边青总多酚工艺

采用超声协同乙醇-铵盐双水相体系提取路边青总多酚,通过单因素和正交试验考查料液比、乙醇初始体积与水初始体积比、提取温度和提取时间对总多酚提取率的影响。结果表明：最佳工艺为料液比1:20(g/mL)、乙醇初始体积与水初始体积比0.8、硫酸铵质量浓度0.27g/mL、提取温度60℃、超声提取时间60min,总多酚提取率为3.04%。本法是一种提取效率高,时间短,能耗低,不影响提取物活性的新工艺。     

超声辅助提取庆阳黄花菜中多糖的动力学研究

目的:建立超声辅助提取黄花菜中多糖的动力学模型。方法:综合考虑提取过程各个因素对黄花菜多糖提取率的影响。将提取率作为考察指标,代入数学模型进行拟合。结果:在建立的提取动力学模型的前提条件上推算出提取黄花菜多糖的速率常数、表观活化能、半衰期和扩散系数等函数值,以Fick扩散定律为基础,黄花菜多糖的动力学模型为In[C∞/C∞-CL]=kt-Inb,活化能为Ea=2.403×10^4J/mol,半衰期线性方程为t1/2=1.9268E6^*exp^-0.03877x,扩散系数回归方程为1×10^-4Ds=0.95889^*exp^0.00705x。结论:动力学模型的建立,黄花菜多糖浓度随着提取过程中温度、时间变化的规律可以较好地反映出来,可以预测各种提取条件下黄花菜多糖的质量浓度,为黄花菜多糖提取工程放大和深入理论研究提供依据。     

响应面法优化款冬花总鞣质提取工艺的研究

目的:优选款冬花总鞣质的提取工艺。方法:采用响应曲面法优选款冬花中鞣质的最佳条件,以提取率为指标,采用EDTA络合滴定法测定提取率。结果:款冬花总鞣质提取的最佳工艺为:丙酮浓度为31%,提取温度30℃,料液比1∶12,提取时间167min。在此条件下,款冬花总鞣质的提取率可达14.97%,RSD(n=5)为0.63%,与预测值15.26%十分接近。结论:该工艺提取冬花中总鞣质是可行的。      

鸡枞菌总多酚提取工艺的优化

以鸡枞菌为试验材料,采用单因素试验和正交试验设计以总多酚提取率为考察指标,对鸡枞菌总多酚的提取工艺进行优化。试验结果表明,鸡枞菌总多酚最佳提取条件为料液比1∶30(g/m L)、提取温度40℃、提取时间1h、浸提3次。在此条件下总多酚的含量可达到15.9 mg/g,其中提取次数、提取时间和料液比对鸡枞菌总多酚的提取率影响极显著(p0.01)。     

Study of Optimal Extraction Conditions for Achieving High Yield and Antioxidant Activity of Tomato Seed Oil

Value of tomato seed has not been fully recognized. The objectives of this research were to establish suitable processing conditions for extracting oil from tomato seed by using solvent, determine the impact of processing conditions on yield and antioxidant activity of extracted oil, and elucidate kinetics of the oil extraction process. Four processing parameters, including time, temperature, solvent-to-solid ratio and particle size were studied. A second order model was established to describe the oil extraction process. Based on the results, increasing temperature, solvent-to-solid ratio, and extraction time increased oil yield. In contrast, larger particle size reduced the oil yield. The recommended oil extraction conditions were 8 min of extraction time at temperature of 25 °C, solvent-to-solids ratio of 5/1 (v/w) and particle size of 0.38 mm, which gave oil yield of 20.32% with recovery rate of 78.56%. The DPPH scavenging activity of extracted oil was not significantly affected by the extraction parameters. The inhibitory concentration (IC(50) ) of tomato seed oil was 8.67 mg/mL which was notably low compared to most vegetable oils. A 2nd order model successfully described the kinetics of tomato oil extraction process and parameters of extraction kinetics including initial extraction rate (h), equilibrium concentration of oil (C(s) ), and the extraction rate constant (k) could be precisely predicted with R(2) of at least 0.957. Practical Application: The study revealed that tomato seed which is typically treated as a low value byproduct of tomato processing has great potential in producing oil with high antioxidant capability. The impact of processing conditions including time, temperature, solvent-to-solid ratio and particle size on yield, and antioxidant activity of extracted tomato seed oil are reported. Optimal conditions and models which describe the extraction process are recommended. The information is vital for determining the extraction processing conditions for industrial production of high quality tomato seed oil.     

Statistical analysis of decay of organophosphorus and pyrethroid insecticides and carbaryl on paddy rice, maize, sunflowers and field peas

A model is developed to describe the decay of seven insecticides on stored paddy rice, maize, sunflowers and peas, and is shown to be more precise than each of six literature models on pesticide decay. It relates residues (R), as a ratio of applied concentration (R(0)), to time after insecticide application (t), modifying the usual first-order kinetics equation lnR=lnR(0)-kt by assuming that the rate constant k has a mixture of values according to a gamma distribution with mean K. The resulting equation is lnR=lnR(0)-Kcln(1+t/c), where c is a constant determined empirically. For large c, this model reduces to the first-order model with K=k. The parameter K is further modelled as linear in temperature for maize and rice. The rate of loss of protectants was found not to be seriously affected by co-application with other insecticides, and this is a useful finding for future studies on rates of loss of grain protectants. The apparent rate of loss was also not seriously affected by the method of analysis, whether by gas chromatography or high-performance liquid chromatography, and this finding supports previous validation of the methods.     

超声波辅助离子液体提取石榴籽中原花青素的工艺及其动力学与热力学分析

探讨了超声波辅助离子液体提取石榴籽中原花青素的工艺条件,以原花青素得率为考察指标,提取时间、提取温度、超声功率和离子液体浓度为实验因子,在单因素实验基础上,通过Box-Behnken实验设计优化最佳提取工艺条件,并对提取过程的动力学和热力学性质进行了分析。结果显示:原花青素的最佳提取工艺条件为:提取时间32 min、提取温度52℃、超声功率300 W、离子液体浓度1.15 mol/L,此条件下的原花青素得率达到1.718%;在该工艺参数下,提取速率常数k值为0.313 min-1,表面扩散系数DS值为7.936×10-5cm2/min,而相同提取条件下,无水乙醇空白对照组的k值仅为0.063 min-1,表面扩散系数DS值为1.597×10-5cm2/min,提取速率明显提高;提取过程的热力学参数,熵ΔH为248.51 k J/mol,焓ΔS为813.69 J/（mol·K）,数值均大于零,说明离子液体提取过程为吸热熵增加过程,自由能ΔG为-18.254 k J/mol,小于零,为自发过程。离子液体提取的工艺参数及动力学与热力学分析,均可用于石榴籽中原花青素提取过程的工程放大和优化控制。      

Extraction of alkylresorcinols from wheat bran with supercritical CO2

The supercritical fluid extraction (SFE) of wheat bran alkylresorcinols has been studied. Extractions were carried out at 40.0 MPa. The effect of particle size, static extraction pretreatment with supercritical CO₂ (SC-CO₂) and extraction temperature on the extraction kinetics was investigated. The extraction yield increased as the particle size decreased and with temperature. Extraction curves present a faster and linear initial extraction period followed by a slower extraction period. Based on these results the approximate mathematical model of Sovová was successfully applied to describe the extraction curves. The total content of alkylresorcinols was determined and compared with the alkylresorcinol content obtained by conventional organic solvent extraction. Due to the amphiphilic nature of these resorcinolic lipids, the extraction yield was higher for polar organic solvents than for SC-CO₂. Characterization of supercritical extracts was also performed by determining the fatty acid composition and antioxidant activity.     

Extraction of saponins and cyclopeptides from cow cockle seed with pressurized low polarity water

Pressurized low polarity water extraction of whole cow cockle seeds was carried out at 160 °C to determine the effect of flow rate (0.5, 1, 2, 4, and 8 mL/min), flow direction (upward and downward flow), and sample size (3 and 6 g) on the recovery of saponins and cyclopeptides. Extraction rate increased whereas loading of the solvent (in the constant rate period) decreased with flow rate. Sample size did not have an effect on total recovery. Similarly, flow direction did not affect total recovery, but extraction of 6 g seeds using upward flow resulted in considerably higher extraction rates early in the extraction. The effect of flow direction was more pronounced for cyclopeptide extraction. The higher extraction rates (lower extraction times) that were attained at higher flow rates were accompanied by increases in solvent to feed ratio and thus less concentrated extracts.     

连续相变萃取灵芝多糖动力学球状模型的建立及其结构特征

根据中草药浸提机制和非稳态扩散理论对灵芝多糖(GLP)的连续相变萃取过程动力学进行研究,研究不同温度、流速和时间下GLP传质动力学,并对多糖结构特征进行分析。以灵芝子实体为原料,采用连续相变萃取技术得到GLP,基于Fick第二定律建立GLP溶出动力学球状模型方程并研究了萃取过程的热力学特性。利用高效凝胶渗透色谱法(HPGPC)研究多糖分子量分布、傅里叶变换红外光谱(FT-IR)对多糖官能团结构进行分析及扫描电子显微镜(SEM)观察多糖形态结构。最佳萃取工艺条件为:温度为373.15 K、流速为28 L/h,时间为190 min,在此条件下GLP得率为2.04%。动力学球状模型方程为ln[(C_∞-C)/C_∞]=π²Dt/R²+ln(π²/6),速率常数k、相对萃余率y=(C_∞-C)/C_∞及半衰期方程y=-7.440 x+2864.4等动力学参数,试验数据与动力学模型计算值吻合良好(R²>0.94),萃取过程符合一阶扩散动力学模型。HPGPC结果表明GLP分子量分布范围为1.35×10³~2.26×10⁷ Da。FT-IR结果表明GLP为β-吡喃型多糖,SEM显示GLP由碎片状聚集体所组成,呈现出褶皱状。该动力学模型可为灵芝多糖连续相变萃取工艺条件优化以及深层次研究奠定理论基础。     

类胡萝卜素清除自由基的动力学及体外模拟消化对清除率的影响

测定不同质量浓度类胡萝卜素在不同温度条件下清除1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基的能力;考察经人工胃液、肠液及胃液-肠液3 种方法模拟消化后类胡萝卜素清除DPPH自由基能力的变化情况。结果表明：反应温度（T）对类胡萝卜素清除DPPH自由基的速率（k）影响显著（P＜0.05）,T升高,k增大,即k45 ℃＞k37 ℃＞k30 ℃,而对清除率（α）无显著影响;类胡萝卜素初始质量浓度（ρ）对α影响显著,ρ升高,α增大,而对k无显著影响;类胡萝卜素对DPPH自由基的清除作用符合一级反应动力学模型;T对半数效应浓度（EC50）、k和半衰期（t1/2）影响显著,T升高,EC50减小（EC50（45 ℃）＜EC50（37 ℃）＜EC50（30 ℃））、k增大（k45 ℃＞k37 ℃＞k30 ℃）、t1/2减小（t1/2（45℃）＜t1/2（37℃）＜t1/2（30 ℃））;表观活化能（Ea）和方程常数（K0）不受ρ的影响,Ea=17.039 kJ/mol、K0=7.38×106;体外模拟消化后的类胡萝卜素对DPPH自由基的清除率减小,且底物浓度越大,清除率下降百分比越大,降幅越小;与油脂混合后的类胡萝卜素经体外模拟消化后对DPPH自由基的清除率低于不加油脂组,即脂溶性的类胡萝卜素与油脂混合后更易被人体消化吸收,但因不同植物油的脂肪酸组成不同,对其消化吸收的影响存在差异。     

随机质心映射优化法(RCO)提取皮亚曼石榴皮中黄酮类化合物

利用随机质心映射优化法(RCO),以乙醇浓度、超声时间、提取温度和料液比为影响因子,研究新疆皮亚曼石榴皮中黄酮类化合物的超声波提取工艺。结果表明:经过RCO两轮循环后得出超声波法提取石榴皮中黄酮类物质最佳工艺:乙醇浓度为87%、超声时间为37 min、提取温度为59℃、料液比为1∶24(g/m L)。优化后皮亚曼石榴皮中总黄酮的得率为25.56%。经过相关性分析得知,提取温度和乙醇浓度对总黄酮的得率影响较大,且呈负相关,表明皮亚曼石榴皮中黄酮类化合物的极性较大。当石榴皮黄酮浓度为12 mg/m L时,对DPPH自由基的清除率可达91.6%。      

植物油热聚合反应动力学研究

以大豆油为原料,通过作图法和稳态近似法确定了油脂的热聚合反应级数、速率常数及动力学方程,结果显示,亚油酸酯异构化反应为一级反应,动力学方程为：c18：2/18：0=11.46e^-0.0137t;大豆油热聚合反应为一级连串反应,动力学方程为：cC=11.46（1-e^-0.0137t）,反应的速率常数为：：k=0.0137.     

云南栽培玛咖总生物碱提取工艺优化研究

以云南栽培玛咖干粉为原料,对其中总生物碱的提取工艺进行优化。采用热水为提取溶剂,以提取温度、提取时间和料液比为考察对象,在单因素优化的基础上设计3因素3水平正交实验,研究玛咖总生物碱的最优提取条件。结果表明,各因素对玛咖总生物碱提取得率的影响顺序依次为:提取时间>料液比>提取温度。最优提取工艺为:料液比1:20(g:mL),温度70℃,时间100min,在此条件下,玛咖总生物碱提取得率为1.58%。