Drying kinetics of grape seeds

Drying of grape seeds representing waste products from white wine processing (Riesling), red wine processing (Cab Franc), and juice processing (Concord) was studied at 40, 50, and 60 °C and constant air velocity of 1.5 m/s. Equilibrium moisture content had a significant effect on the normalized drying curve and was determined for each grape seed at each drying temperature. Effective moisture diffusivity ranged between 1.57 and 3.96 × 10⁻¹⁰ m²/s for Riesling seeds, 2.93–5.91 × 10⁻¹⁰ m²/s for Concord seeds, and 3.89–8.03 × 10⁻¹⁰ m²/s for Cab Franc seeds. The temperature dependence of the effective diffusivity followed an Arrhenius relationship, and the activation energies were 40.14 kJ/mol for Riesling seeds, 30.45 kJ/mol for Concord seeds, and 31.47 kJ/mol for Cab Franc seeds. Three thin-layer models were used to predict the drying curves: Page model, Lewis model, and the Henderson–Pabis model. All three models were found to produce accurate predictions compared to the mass average moisture loss for each grape seed variety (percent error less than 10%), and the Lewis model was shown to be an excellent model for predicting all three grape seed varieties (percent error less than 5%).     

莲子微波真空干燥特性及动力学模型的研究

为探究莲子微波真空干燥过程中水分变化规律,本文以新鲜莲子为对象,考察不同微波强度和真空度对莲子微波真空干燥特性的影响,在此基础上构建其干燥动力学模型。结果表明,莲子微波真空干燥过程为降速干燥阶段,微波强度和真空度对莲子干燥速率和干燥时间影响均显著(p<0.05)。随着微波强度和真空度的增大,莲子干燥速率增加,干燥时间缩短。经6种干燥模型非线性回归拟合发现,Tian模型R2最高,RMSE、SSE及χ2最小,该模型能较好地描述和预测莲子微波真空干燥过程中水分变化规律。      

葡萄籽口含片的制备

通过提取葡萄籽中原花青素,来制备具有保健功能的口含片.采用中心组合设计对原花青素的提取工艺进行优化,从而确定最佳提取工艺条件:乙醇浓度71.25％、提取温度46.08℃、超声波时间42.74 min,该条件下得出原花青素提取率为2.521％,与预测值2.534％相符.利用旋转蒸发仪对提取液进行浓缩,再冷冻干燥得到粉末状提取物,辅以甘露糖及羟丙甲纤维素等,经混合、造粒、干燥、压片等工序,制成低热量、具有保健功能的口含片.     

葡萄籽中原花青素稳定性研究

考察了温度、pH值、金属离子、Vc、光照等因素对原花青素稳定性的影响.结果表明,温度低于50℃时,原花青素很稳定,当温度高于50℃时,稳定性随温度的升高而降低;在相同温度条件下,pH值越低,原花青素的稳定性就越高,随着pH值的升高,稳定性逐渐降低;在相同pH值条件下,温度越高,原花青素的含量下降越快.在不同pH值条件下原花青素呈现不同的颜色;金属离子中以Fe3+和Ca2+的影响最为显著,Zn2+、Ni2+、Na+离子影响较小;Vc可以提高原花青素的稳定性,且提高的效果同浓度有关;光照使原花青素发生光解变质并使其稳定性降低.     

葡萄籽中低聚原花青素的提取研究

以葡萄酒生产加工的副产品--葡萄籽为原料提取原花青素,并对影响原花青素提取率的因素,即提取溶剂的选择、提取温度、提取时间及料液比等进行考察,并通过正交试验确定最适的提取条件为以70%丙酮作为提取剂,提取温度为60℃,提取料液比为1:8,提取时间为3h.提取物中原花青素含量可达7.88%.     

葡萄籽原花青素的纤维素酶辅助提取工艺优化

本文首先在单因素试验的基础上,采用Box - Behnken设计对葡萄籽原花青素的纤维素酶辅助提取工艺中的pH、酶浓度和酶解温度3因子的最优化组合进行了定量研究,建立并分析了各因子与得率关系的数学模型;然后与传统提取方法进行了比较.结果表明:最佳的工艺条件为pH 4.4、酶浓度0.4％和酶解温度47.8℃.经试验验证,在此条件下,得率为3.37％,与理论计算值3.35％基本一致,说明回归模型能较好地预测葡萄籽中原花青素的提取得率;与传统提取方法相比,纤维素酶辅助提取时间短,得率高.     

葡萄籽原花青素的提取工艺研究

以乙醇溶液为提取液,采用正交试验优化了原花青素提取工艺条件。最佳提取条件为:葡萄籽脱脂粉碎处理后,用60%乙醇溶液回流提取2次,每次30 min,所得浸膏得率为12.82%,原花青素含量为34.97%。     

Drying of pomegranate seeds using infrared radiation

Effect of different infrared (IR) power levels on drying kinetics of pomegranate seeds was investigated. The pomegranate seeds were dried at 83, 104, 125, and 146 W IR power levels. It was observed that the power levels affected the drying rate and time. Drying time reduced from 150 to 60 min as the IR power level increased from 83 to 146 W. The experimental data obtained from drying study were fitted with 10 mathematical models to evaluate the drying kinetics of the pomegranate seeds. The Page, Midilli et al., and Weibull models are given better prediction than the other models and satisfactorily described drying kinetics of pomegranate seeds. Effective diffusivity varied from 1.96 to 6.29×10^?11 m²/s and was significantly influenced by IR power.     

葡萄籽原花青素的提取与分离

原花青素是葡萄籽中含有的一种重要的生理活性物质。采用溶剂浸提的方法从葡萄籽中提取原花青素,并通过单因素试验和正交试验优化了最佳提取工艺参数为:乙醇浓度70%,浸提时间120m in,料液比1∶20,浸提温度40℃。选取四种不同的大孔树脂(DA201、AB-8、HPD-100、HPD-700)对最佳条件下提取的粗提液进行静态吸附、解吸实验和动态实验,结果表明:DA201为吸附葡萄籽原花青素的最佳树脂;当原花青素浓度为0.15mg/mL时,上样流速为1mL/m in,洗脱流速为1mL/m in,洗脱剂乙醇浓度为70%,用量为5BV时的纯化效果最佳。     

葡萄籽中原花青素稳定性研究

研究了葡萄籽中原花青素的稳定性,结果表明：葡萄籽中原花青素的最大吸收波长λmax=500 nm;温度对该色素有一定的降解作用,在加工中热处理温度应不高于60℃;pH对该色素的影响明显,宜在酸性食品中应用;柠檬酸对该色素有一定的增色作用;蔗糖、葡萄糖、紫外光照射对该色素影响作用很小;低浓度的苯甲酸钠和山梨酸钾对该色素无影响,高浓度的则有降解作用;而H2O2、Na2SO3及VC则对该色素有破坏作用.     

Drying kinetics of rough rice grain

It is shown that thin layer drying of rewetted rough rice grain in air flow may be interpreted in terms of Fick's law solution for diffusion from a sphere. Diffusion coefficients were calculated by non-linear regression analysis comparing actual and predicted values of grain moisture content. The activation energy of rough rice was calculated assuming an Arrhenius type equation for moisture diffusivity dependence on the inverse of the absolute temperature.     

Evidence for galloylated type-A procyanidins in grape seeds

In this work, procyanidins were extracted with methanol from the seeds of white and red grape varieties, and fractionated using graded methanol/chloroform precipitation in order to obtain the oligomers of lower molecular weight. These were analyzed by electrospray ionization-mass spectrometry (ESI-MS and ESI-MS/MS) in the positive mode. Protonated molecules, [M+H]⁺, of procyanidin species of nongalloylated and monogalloylated type-A and type-B oligomers, with degree of polymerisation 2–5, and digalloylated oligomers, with degree of polymerisation 2–3, were observed in the ESI-MS spectra. Type-A procyanidin abundance accounted for 60–80% of the abundance of the corresponding type-B species. Independent of the interflavanic linkage, the abundance of monogalloylated dimers accounted for 20% of the abundance of the corresponding nongalloylated ones. For the higher degrees of polymerisation, the abundance of galloylated oligomers was shown to reach up to 60% of the abundance of the corresponding nongalloylated oligomers. Thiolytic analyses showed that the type-A interflavanic linkages were present in the terminal units whereas the type-B interflavanic linkages were present as extension units. Although many reports are already available regarding the analyses of procyanidin polymers and grape seed procyanidins, this is the first report for the occurrence of type-A galloylated procyanidins. The similarity of the relative abundances and structural features observed in the samples of both white and red grape varieties, shows that these are characteristic of grape seeds.     

不同种类葡萄籽综合营养成分分析

葡萄籽含有丰富的营养元素,在食品、医药和工业等领域具有重要的应用前景,对不同品种的葡萄籽营养成分的全面分析有利于葡萄籽的精准加工和资源的合理利用。本文系统的研究了玫瑰香、赤霞珠和巨峰三种葡萄籽所含营养成分差异,结果表明三种葡萄籽所含脂肪和蛋白质含量几乎无差异,而在其它方面差异显著;玫瑰香葡萄籽富含脯氨酸、铁元素和膳食纤维;赤霞珠葡萄籽中谷氨酸、镁元素、多糖、多酚和原花青素含量最高;而巨峰葡萄籽所含必需氨基酸比例、矿物质元素和膳食纤维含量最多。通过上述三种葡萄籽的营养成分比较分析可得出每种葡萄籽在其营养方面具有的优势,可为今后葡萄籽的精准加工提供方向,从而高效的提高葡萄籽资源价值。     

Effect of heating conditions of grape seeds on the antioxidant activity of grape seed extracts

This study was carried out to evaluate the effect of heating and physical conditions of grape seeds on the antioxidant activity of their extracts. Two forms of grape seeds, whole and powdered forms, were heated at four different temperatures −50, 100, 150 and 200 °C. After heating, grape seeds were extracted with 70% ethanol (0.1 g grape seed/10 mL of 70% ethanol), and total phenol contents (TPC), radical scavenging activity (RSA) and reducing power of the extracts were determined. Thermal treatment of grape seed increased the antioxidant activity of extracts. The maximum TPC and RSA of whole grape seed extract (WGSE) were achieved when the seeds were heat-treated at 150 °C for 40 min, while that of powdered grape seed extract (PGSE) were at 100 °C for 10 min, and were greater than that of the non-treated control. Also, the reducing powers of WGSE and PGSE slightly increased at the conditions. According to the GC-MS analysis, several low-molecular-weight phenolic compounds such as azelaic acid, 3,4-dihydroxy benzoic acid, and o-cinnamic acid were newly formed in the WGSE heated at 150 °C for 40 min. There were slight differences in the kinds of phenolic compounds between non-heated and heated GSE. In HPLC analysis, the contents of gallocatechin gallate and caffeine in GSE significantly increased by heat treatment. These results indicated that antioxidant activity of GSE was affected by heating conditions (temperature and time) and physical conditions of grape seeds at the time of heat treatments.     

葡萄籽中油脂脂肪酸和蛋白质组分分析

以普通葡萄籽和山葡萄籽为原料,分析了2种葡萄籽油中脂肪酸含量及组成,测定了油中维生素E含量和粕中粗蛋白含量,并用氨基酸测定仪分析了蛋白质氨基酸组成及含量。结果表明:普通葡萄籽和山葡萄籽含油量分别为12.63%和13.51%;维生素E含量分别为3.83×10~2μg/g和3.99×10~2μg/g;蛋白质含量分别为12.30%和12.76%,均为完全蛋白质,含17种氨基酸,蛋白质在水中的溶解度在pH为8左右最大,在pH为4左右最小。为葡萄籽的开发利用提供了科学依据。     

原花青素的超声提取工艺研究

首先优化出了超声波提取葡萄籽中原花青素的最佳工艺参数,然后将超声波提取和其它提取方法进行了对比。结果表明,超声波提取原花青素的最佳工艺参数为乙醇浓度为70%、液料比为18:1、超声波功率达到600W、提取时间为50min、占空比达到5/5、提取温度70℃,此时原花青素的最佳得率为3.424%;与其它提取方法相比,超声波辅助提取时间短,得率高。     

葡萄籽原花青素提取工艺的研究

原花青素是广泛存在于植物体内的一大类多酚化合物,在酸性条件下加热会生产花青素。原花青素具有极高的抗氧化性和自由基清除能力,还有消炎抗癌、抗衰老等作用,因此广泛应用于医药、食品、保健和化妆品等方面。葡萄籽中含有大量的优质原花青素,通过乙醇浸提法提取葡萄籽中的原花青素,既可以充分利用葡萄酒副产物,又可以生产优质原花青素。以原花青素提取量和DPPH自由基清除能力为试验指标确定乙醇法提取葡萄籽原花青素的最佳工艺条件,为原花青素的进一步开发和利用提供支持。经过单因素试验与正交试验的反复探索得出葡萄籽原花青素提取的最佳工艺条件为:料液比1∶10,提取时间90 min,提取温度20℃,乙醇浓度70%,pH=4,经验证实验确定原花青素提取量为1.584 mg/g,DPPH自由基清除能力为12.41μmol/g。     

分光光度法测定葡萄籽中原花青素的含量

改进葡萄籽提取物中原花青素的测定方法--铁盐催化比色法,并探讨了影响新体系催化比色的有关因素.经验证,最佳测定条件为:硫酸高铁铵(FeNH4(SO4)2)浓度为0.6～0.8 g/L,盐酸浓度为0.6 mol/L,在乙二醇介质中于沸水浴(95℃)下反应40 min.最低检测限为4μg/mL,平均回收率为100.57%,RSD为2.74%(n=4).原花青素浓度在30～480 μg/mL范围内与吸光值呈线性相关(R2=0.99911,符合测定要求.     

油茶籽干燥工艺与设备研究

为了更好地了解我国油茶籽干燥工艺与相关设备,对现有油茶籽干燥中存在的问题、干燥工艺及塔式烘干设备做了相关介绍。油茶籽的干燥对脱蒲、储存及加工均具有重要意义。油茶籽热风干燥工艺研究中,热风温度的选择需兼顾热能利用率和油茶籽干燥后的品质。烘干塔的工艺设计计算为油茶籽的烘干塔设计提供理论依据。     

普鲁兰基多糖成膜溶液干燥动力学研究

研究普鲁兰及普鲁兰—聚乙二醇可食用成膜溶液的干燥动力学。结果表明:所有样品在干燥过程中分为加速、降速和平衡3个阶段。纯普鲁兰样品干燥过程符合Wang and singh模型,普鲁兰—聚乙二醇复合膜液则符合Modified Henderson and pabis模型。当干燥温度由40℃升高到70℃,普鲁兰膜液的有效水分扩散系数从0.019 6×10~(-11) m/s~2增至0.255 7×10~(-11) m/s~2,而普鲁兰—聚乙二醇复合样品从2.400×10~(-11) m/s~2增至11.388×10~(-11) m/s~2。可见随着干燥温度的升高,膜液的有效水分扩散系数值也随之变大;并且在相同干燥温度下,普鲁兰膜液的有效水分扩散系数值比普鲁兰—聚乙二醇复合样品要低。通过Arrhenius类型方程计算得到普鲁兰膜液的干燥活化能为9 114.8kJ/mol,而普鲁兰—聚乙二醇复合膜液干燥活化能为2 475.2kJ/mol。