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1.
建立高效液相色谱(HPLC)测定姜黄根茎以及姜黄素饮料中姜黄素类化合物的含量。样品用乙醇辅助超声波提取,以DIKMA Platisil ODS(4.6 mm×250 mm,5μm)柱为分析柱,乙腈和水(磷酸调p H为3.0)为流动相进行梯度洗脱,流速:1.0 m L/min,检测波长:425 nm,柱温:30℃。姜黄素、去甲氧基姜黄素、双去甲氧基姜黄素分别在1.00~200.00,0.96~192.00,0.96~192.00 mg/L范围内线性关系良好,相关系数R2>0.999。平均回收率分别为106.87%(RSD=1.24%)、105.28%(RSD=0.48%)、96.86%(RSD=0.26%)。本方法操作简单、快速、重复性好,可用于姜黄根茎及饮料中的姜黄素类化合物的检测。   相似文献   

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A theoretical and experimental study for the drying kinetics of Ataulfo mango slices was carried out. In the study different thicknesses, air drying temperature, maturity degree and non-isotropic mass diffusion were considerate. The 2D temperature and moisture distributions inside the slice were predicted by using a theoretical model. The water effective diffusion coefficient, the convective heat and mass transfer coefficients, the drying curves and the center temperature were getting by the experimental model. A parametric study was carried out in the ranging of air drying temperatures from 50 to 70 °C, slices with thickness of 2–5 mm and maturity degree from 13.2 to 22°Brix. It was found from the experimental results that slices of Ataulfo mango present an isotropic behavior with an uncertainty of 2.47%. The drying rate reduces in 4.5% as 1 mm thickness increase, and decreases in 8.0% for each 1°Brix increased.  相似文献   

4.
太阳能热泵联合干燥技术在农副产品中应用与展望   总被引:1,自引:0,他引:1  
干燥技术被广泛应用于农业、食品和水产品等加工领域。太阳能热泵联合干燥装置既能充分利用广泛的太阳能资源,同时又能解决太阳能不稳定、易受天气影响等因素,具有广阔的应用前景;又因其节能,改善干燥产品品质等因素,而逐渐被干燥行业所推广应用。阐述了太阳能热泵联合干燥的工作模式,综述了太阳能热泵联合干燥在木材、农副产品等行业的应用现状,并提出了太阳能热泵联合干燥技术的现存问题和发展展望,可为干燥技术的选择提供参考。  相似文献   

5.
The present investigation is contemplated to fill a gap in analytical modelling of coupled heat and mass transfer during convective drying process. A transport model to describe the temperature and moisture evolutions of mango slab is established. The main innovation introduced in this study is represented with the procedure of temperature and moisture predictions. Mango fruit dehydration can be easily simulated with implementation of the present advanced analytical technique at different operating conditions. Moreover, the temperature and moisture history of mango slice are presented for varying values of the drying air factors counting temperature, velocity, relative humidity and initial food temperature. This work confirms that notable time can be saved without sacrificing accuracy by applying proposed model. This method is expected to be useful for fast and accurate drying simulation. The agreement between published experimental results and model predictions is remarkable and an accurate simulation of experimental drying curves is obtained.  相似文献   

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Simulation and numerical modeling are becoming increasingly popular due to the ability to seek solutions for a problem without undertaking real-life experiments. For the problems of heat transfer, these techniques to generate relevant data by incorporating different changes to the input parameters. Heat transfer property of textile materials is a major concern since it influences comfort properties of clothing. In this paper, numerical simulation was applied to evaluate the heat flux, temperature distributions, and convective heat transfer coefficients of the fibrous insulating materials treated with aerogel. The computational model simulated the insulation behavior of nonwoven fabrics without and with aerogel. Ansys and Comsol were used to model and simulate heat transfer. The simulation was performed assuming laminar flow and since the Mach number was < 0.3, the compressible flow model with Mach number < 0.3 was used. The results of simulation were correlated to experimental measurements for validation. Furthermore, aerogel-treated fabric samples showed better thermal performance. Using this model, the heat transfer properties of the nonwoven fabrics treated with aerogel can be optimized further.  相似文献   

8.
仓储粮堆内部自然对流和热湿传递的数学分析及验证   总被引:2,自引:0,他引:2  
本文基于仓储粮堆内部自然对流、热湿耦合传递的数学模型,采用数学分析的方法对模型中各个方程中的各项的物理意义和数量级大小进行了分析,探讨了仓储粮堆内部自然对流、热量传递和水分迁移过程的相互关系。提出了判断粮堆内部自然对流强弱的瑞利数及其影响因素,分析了仓型结构、粮种及仓外大气温度对粮堆内部自然对流、热量传递和水分迁移的影响,并通过数值模拟对数学分析结果进行了验证。结果表明,数学分析方法是分析仓储粮堆内部自然对流、热量传递和水分迁移过程的一种有效途径,数学分析的结果可以为仓型设计、储粮生态系统的模拟、仓储技术管理提供借鉴。  相似文献   

9.
The influence of drying on the aroma compounds, from a chemical and sensory standpoint, and on the structural integrity of basil (Ocimum basilicum L) was evaluated. The drying methods tested were oven drying at 45 °C, air drying at room temperature and freeze‐drying. The volatile compounds of fresh and dried basil were extracted and concentrated by simultaneous distillation/extraction and analysed by gas chromatography/mass spectrometry. In all, 27 volatile components were identified, linalool being the major component, followed by eugenol. The total quantity of volatiles of fresh basil decreased considerably during oven drying and freeze‐drying, whereas air drying of basil at room temperature brought about only small losses of volatile components. The cell damage produced on basil leaves during drying was evaluated by scanning electron microscopy. From a sensory standpoint, fresh basil was described as having a fresh, herbaceous and floral odour, while the dried samples had a mentholated, spicy, hay‐like and earthy odour. Copyright © 2004 Society of Chemical Industry  相似文献   

10.
Significant variations were observed in the concentration of pigments (10·0–17·0%, moisture-free basis) and flavour components during different post-harvest processing conditions of saffron (stigmas ex Crocus sativus L). The crocin pigments concentration was highest (15–17%) in the saffron samples dried between 35°C and 50°C either in a solar dryer or in an oven dryer and this also resulted in considerable reduction of normal drying time. Under these conditions the main flavouring component, safranal, was at its peak value of 60% in the oil in almost all the samples except the vacuum oven dried samples which interestingly contained 4-β-hydroxysafranal in major amounts. Studies indicated that 4-β-hydroxysafranal may be an intermediate in the formation of safranal. It was observed that prolonged storage affected the pigments and flavour concentration to a great extent, but proper packaging and storage with 5% moisture in the saffron reduced the deterioration, thereby increasing the shelflife of the product.  相似文献   

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In this study, anthocyanins in three fresh fig varieties (Ficus carica L.) cultivated in Turkey were characterised and quantified by HPLC/DAD and HPLC/MS. In addition, the carotenoid composition of Sar?lop and Sar?zeybek, yellow fig varieties, was determined, and then the ripening‐ and drying‐related changes in carotenoids and surface colour of figs were monitored during conventional sun‐drying. Four different anthocyanins, cyanidin‐3‐glucoside, cyanidin‐3,5‐diglucoside, cyanidin‐3‐rutinoside (major anthocyanin) and pelargonidin‐3‐glucoside, were identified in samples. Lutein, zeaxanthin, β‐cryptoxanthin and β‐carotene were carotenoids in yellow fig varieties. Approximately 80% of carotenoid compounds in yellow fig varieties degraded at the end of drying (i.e. seventh day). L (lightness), a (redness and greenness) and b (yellowness and blueness) colour parameters were measured by Hunter Lab system. Great changes in carotenoid composition and surface colour were observed at ripening stage on tree. A significant reduction in L and b values that refers to browning in figs was made in the first 3 days of drying process.  相似文献   

12.
Socks are prevented against wrinkle formation by preheat setting in greige form prior to wet processing. The current study is proposed to analyze the effect of socks presetting process on thermopysiological and wicking properties of comfort. In this analysis, main yarn linear density, plaiting yarn composition and number of needles are taken as variable on same machine setting. Sock samples were analyzed for comfort parameters (thermal conductivity, thermal resistivity, thermal absorptivity, thermal diffusivity, relative water vapor permeability (RWVP (%)), evaporation resistance (Ret), air permeability, vertical wicking, absorbency and color strength (K/S) value) after various processes (preheat setting, dyeing and postheat setting). The statistical analysis showed that preheat set process significantly affects vertical wicking, K/S value, absorbency, thermal conductivity, thermal resistivity and thermal diffusivity, respectively. While thermal absorptivity, air permeability, porosity, RWVP (%) and Ret couldn’t show a significant impact.  相似文献   

13.
为了避免传统温度传感器对织物表面温度传递的影响,利用红外热像仪开发一种无干扰的精确计测织物表面温度的新方法。并利用该方法分析比较大豆蛋白复合纤维、莫代尔等新型再生纤维织物的热湿耦合作用。结果表明:大豆蛋白复合纤维、莫代尔纤维及其混纺织物的热湿耦合作用规律是相似的。织物温度变化参数聚类分析表明,可用织物湿热温度上升速率和织物湿热温度与干热温度之差的最大值作为织物热湿耦合作用的主要表征指标。  相似文献   

14.
通过建立垂直管吸收器内泡式吸收过程中传热传质的数学物理模型,研究了泡式吸收方式;利用模型对吸收过程中出现的搅拌流、活塞流、泡状流等分别进行分析,获得了泡式吸收方式吸收过程中的一些传热传质特性.  相似文献   

15.
基于COMSOL的平房仓冷却通风过程中粮堆热湿耦合传递研究   总被引:2,自引:0,他引:2  
粮仓冷却干燥通风是确保储粮安全的重要技术措施,在此过程中粮堆内部的热湿耦合迁移过程非常复杂。在COMSOL软件中,建立了冷却干燥通风过程中高大平房仓的三维物理模型,通过修改COMSOL内置材料方程、耦合渗流、能量守恒、动量守恒和水分迁移控制方程,以实测的送风空气温度和湿度为入口边界条件,数值模拟了湍流、湿空气传热、湿空气传质、多孔介质传热、多孔介质传质等多个物理场,并考虑了热湿耦合、温度耦合和流动耦合,对高大平房仓粮堆内冷却干燥通风过程中的热湿迁移规律进行了研究。基于实际高大平房仓的验证结果表明,通过修改COMSOL内置方程可以准确模拟预测冷却干燥通风过程中粮堆内热湿耦合传递过程,数值模拟结果可用于指导粮仓冷却干燥通风过程和粮仓通风系统优化。  相似文献   

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腌干鲢鱼组织蛋白酶B、L活力变化的响应面法预测研究   总被引:1,自引:0,他引:1  
高瑞昌  苏丽  黄星奕  袁丽  马海乐 《食品科学》2012,33(17):136-140
以鲢鱼为原料,进行腌制和热泵干燥加工,研究内源组织蛋白酶B、L活性在加工过程中的变化。选取加工过程对鲢鱼(Hypophthalmichthys molitrix)组织蛋白酶B、L活力影响较大的3个工艺参数(温度、pH值、盐质量分数)作为试验因素,并根据酶学特性和干燥过程中各理化指标的测定结果确定其试验水平。采用响应面法考察此3因素对组织蛋白酶B、L活性的影响,并根据回归方程对腊干鲢鱼加工过程中的组织蛋白酶活力进行预测。结果表明:回归方程可用于组织蛋白酶B、L实际活力预测;两种酶的潜在活力在加工过程中均呈下降趋势,加工结束时组织蛋白酶B和L的潜在酶活力分别为初始的43.18%和26.08%;通过回归方程对组织蛋白酶B、L在腌制前、腌制后、干燥2d、干燥5d、干燥7d实际活力进行预测,组织蛋白酶B实际酶活力分别为潜在酶活力的36.7%、39.9%、46.5%、46.5%和53.5%,而组织蛋白酶L则为6.6%、5.6%、10.4%、10%和12.6%。  相似文献   

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为丰富贵州地方特色调味品和提高香菇的综合利用价值,研发具有民族风味的香菇调味酱。本研究以黔产等外级香菇、糟辣椒为主料,采用模糊数学综合评价法和正交试验优化其配方,并对其感官品质、理化及微生物指标进行分析。结果表明,香菇酸辣酱在基础配方(15.1%糍粑辣椒、7.5%番茄酱、3.8%豆瓣酱、0.7%味精、1.4%芝麻、1.4%料酒和90 g食用油)下,添加53%香菇丁、15.1%糟辣椒、0.7%食盐和0.7%白砂糖后酱体感官评分为86.7±2.36,产品亮度值(L*)、红度值(a*)、黄度值(b*)分别为33.62、14.76、13.01,香菇丁的硬度、咀嚼性、弹性、挤压恢复力达到969.04、636.87、0.87、0.32 g。该产品水分和微生物指标均符合该类产品的安全限值,且氨基酸态氮、蛋白质和碳水化合物分别为7.95、5.21 g/100 g和346.61 mg/g;气相色谱-质谱分析结果表明香菇酸辣酱中的主效风味物质是糟辣椒在炒制过程中形成的醇类、烯类、酮类等物质。本研究为香菇及其他食用菌与地方风味特色调味品有机结合的精深加工提供理论依据。  相似文献   

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This study was conducted to evaluate the convective heat transfer coefficient between Newtonian and non-Newtonian fluids and food particles inside of a glass vessel and to assess the effect of controlled variables: convection phenomena, heating temperature, immersion fluid, and different food particles. The coefficient was evaluated from the sample temperature as a function of the heating time by two approaches: a lumped parameter method and an analytical methodology. High values corresponded to heating in Newtonian fluids (70–181, 57–248 W/m2 K), and lower corresponded in non Newtonian fluids (31–169, 28–167 W/m2 K). Similarly, major heat transfer coefficient corresponded to the heating of mushrooms (32–110, 28–132 W/m2 K), followed by tomatoes (30–181, 35–183 W/m2 K) and potatoes (31–148, 34–248 W/m2 K), respectively. Fluid properties were more important than the thermal properties of the particles. This coefficient was higher at 85 °C in both types of fluids. Both methods generated satisfactory values, but the analytical approach showed more accuracy.  相似文献   

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