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1.
便携式煎炸油极性组分快速检测仪的设计   总被引:2,自引:1,他引:1  
介绍了一种采用传感器方法检测煎炸油极性组分的检测仪。该仪器利用叉指电极式电容传感器检测煎炸油介电常数的变化情况,通过一个电容/频率转换电路将电容的变化量转换为便于测量的频率形式,测得输出频率的变化情况反映煎炸油介电常数的变化情况。最后实验结果表明:使用该仪器测得的输出频率变化量与柱层析法测得的煎炸油极性组分变化量之间具有较好的相关性。这种检测方法可用于实际检测,且该仪器便于携带、检测速度快,便于现场检测。  相似文献   

2.
基于压电传感器对介质的介电特性有灵敏的频率变化响应,建立快速测定煎炸油极性组分的压电传感法。获取煎炸油的频率响应曲线,采用Boltzmann对响应曲线进行拟合,并提取可用于测定煎炸油的压电频率特征值,结合国标柱层析法建立校正集煎炸油极性组分含量与压电频率特征值之间的标定方程:Y=9 008 070-66X,r=0.993;根据标定方程,结合国标法规定的煎炸油合格标准判别阈值27%,获得压电传感法判别阈值为9 006 281 Hz。采用压电传感法对验证集和随机挑选的油样品的极性组分含量进行检测,同时采用国标法进行对照测定。结果表明,所提出的压电传感法与国标法在测定的准确性和精密度上没有显著差异,压电传感法具有快速、简便的优势,该法有望运用于油品监督的现场检测中。  相似文献   

3.
《粮食与油脂》2017,(6):91-93
现有煎炸油质量评价指标存在特征指标专一性不强、适用范围有限等缺陷。对煎炸油中极性组分与TGP相关性进行研究,结果表明,极性组分与TGP随煎炸时间的延长呈线性增加关系。通过试验得出多次使用的煎炸老油中TGP含量远高于新鲜煎炸油,用TGP含量评价煎炸油质量具有可行性。相较PCs指标,TGP的稳定性更能使其客观反应油脂的新鲜程度。  相似文献   

4.
真空醋渍黄瓜品质的介电检测   总被引:1,自引:1,他引:0       下载免费PDF全文
通过测量醋渍黄瓜的介电特性来衡量其品质并作为一种潜在的非损伤性评价手段。研究采用平行板电极测量了经过不同时间真空醋渍处理的黄瓜于100 kHz~12 MHz的介电特性,同时测量了反映醋渍黄瓜理化品质的参数,如酸度、盐度、亚硝酸盐含量、质构参数。研究结果表明,在整个频率区间,真空醋渍黄瓜的相对介电常数和介电损耗因子都随频率的增加而单调递减,真空醋渍时间与介电参数存在负相关关系。真空醋渍黄瓜的介电参数与盐分和亚硝酸盐含量存在着较好的相关性,然而介电参数与酸度、质构指标之间的相关性不明显。在2.26 MHz和12 MHz频率下,相对介电常数与盐分呈现出良好的线性关系,线性拟合方程的决定系数R2高达0.9813和0.9858;该研究为真空醋渍蔬菜快速检测仪器的开发提供了理论参考。  相似文献   

5.
煎炸食品一直受到消费者的喜爱,煎炸食品的质量与煎炸油的品质息息相关。传统评价煎炸油品质的理化方法检验费时、操作繁琐、易接触有毒试剂,不能实现在线检测。低场核磁共振技术(LF-NMR)是一种快速、准确、无损的检测方法。以大豆油和添加抗氧化剂大豆油为原料、薯条为煎炸食品,对大豆煎炸油进行理化指标及低场核磁检测。通过研究LF-NMR检测参数S_(21)及t_(2w)与煎炸时间、酸价、羰基价、极性组分含量的相关性,发现S_(21)与2种大豆煎炸油的上述指标均呈正相关、t_(2w)与之均呈负相关,且相关性良好,相关系数在0.905 8~0.994之间。说明利用低场核磁共振技术检测的S_(21)和t_(2w)可以有效地反映大豆煎炸油品质的变化,且不受抗氧化剂的影响。  相似文献   

6.
采用制备型快速柱层析,建立快速分离制备并检测煎炸油中极性组分含量的技术。利用油脂极性组分专用中压制备液相色谱技术,用专用的商品化FLASH柱为分离制备色谱柱,以体积比8713的石油醚—乙醚为洗脱液,洗脱液流速25mL/min,发现当非极性组分洗脱11 min时,恰好能实现煎炸油中极性与非极性组分的分离,且分离速度快,仅需41min,检测重复性RSD5%,均优于传统人工柱层析技术,与传统人工柱层析技术的相比,其相对偏差也±6%,表明基本一致。  相似文献   

7.
电导率法快速检测煎炸油极性组分含量的研究   总被引:1,自引:0,他引:1  
以大豆油、棕榈油和米糠油为煎炸用油,在(190±5)℃的煎炸温度下进行32 h连续煎炸油条试验,通过对不同煎炸时间所取煎炸油样极性组分含量和电导率值的测定以及两者之间对应关系的对比分析,研究电导率法在快速检测煎炸油中极性组分含量方面的应用。结果表明,大豆油、棕榈油和米糠油的极性组分含量均随煎炸时间的延长而增大;电导率值随煎炸时间的延长呈波动变化,整体呈增大趋势;极性组分含量和电导率值之间无显著线性关系。因此,电导率法可用于油脂是否经过煎炸的快速鉴别及煎炸程度的初步鉴别,但能否应用于煎炸油中极性组分含量的快速测定或应用电导率值表示极性组分含量还需进一步深入研究,同时应对电导率值测定方法进行完善和规范。  相似文献   

8.
侯靖 《中国油脂》2021,46(11):36-39
为了探究棕榈油在煎炸过程中化学成分的变化与极性组分之间的相关性,采用气相色谱-质谱联用技术获取了不同煎炸时间煎炸油的化学成分信息,结合化学计量学软件进行数据筛选、主成分分析与聚类分析。结果表明:经过筛选后的数据,不同煎炸时间煎炸油在主成分得分图上区分明显;聚类分析可将煎炸不同时间的煎炸油分成三类,每类之间化学成分差异明显,其中过度煎炸组极性组分含量基本大于27%;初步鉴别出9种煎炸过程中产生的差异性化合物,这些化合物的含量变化均与极性组分含量呈明显的线性关系(R2>0.95)。研究表明,煎炸油在煎炸过程中化学成分会发生变化,部分变化与极性组分含量呈线性相关,极性组分含量可以作为评判煎炸油劣变程度的有效依据。  相似文献   

9.
随着时代的发展以及技术的进步,人们对用于煎炸食品的油脂要求也逐渐提高。多光谱法快速无损检测技术,不仅优于传统方法对样品进行无损检测,而且检测方法准确快速。研究分别利用近红外、中红外、拉曼光谱技术,将测量所得到的油样光谱数据借助分析软件和化学计量学方法,结合光谱预处理和偏最小二乘法(PLS)的数据分析方法,对煎炸油样的极性组分进行建模及校正分析。结果表明,通过不同光谱预处理后再结合PLS对近红外、中红外、拉曼光谱的建模分析以及对比发现拉曼光谱多建模型较为精确,对验证集的光谱对应的极性组分预测较红外光谱的预测准确。以研制新型专用煎炸油为目的进行研究探讨,旨在生产一种新型专用的煎炸油。  相似文献   

10.
电导率法快速检测煎炸油品质的研究   总被引:3,自引:0,他引:3  
本文对煎炸油品质的电导率法快速检测进行了研究。以猪油和花生油为煎炸用油,进行连续煎炸,采用柱层析法测定煎炸油中极性组分的含量;采用电导率法测定相应煎炸油的电导率。结果表明,猪油和花生油的极性物质含量随煎炸时间的延长而不断增大;而电导率随时间的变化规律不明显;极性物质含量和电导率的线性关系不显著;加入抗氧化剂的食用油中极性物质含量相应减少,增加较缓慢。因此,电导率法能否快速检测煎炸油品质还需进一步的研究。  相似文献   

11.
Evaluation of New Methods for the Assessment of Used Frying Oils   总被引:3,自引:0,他引:3  
Three methods recently introduced for quality assessment of frying oils were compared. These were: column chromatography of polar components, dielectric constant measurement, and GLC of triglyceride dimers. For a given frying operation all three methods correlated well with each other and with time of frying, while large differences were obtained for samples of unknown history. The dielectric readings were found to represent a net balance of opposing effects from two groups of compounds. The GLC method was found to be simpler and more specific than the column technique.  相似文献   

12.
BACKGROUND: There is a need for frying oils with reduced trans fatty acid content and increased oxidative stability. This study was conducted to measure and compare frying oil quality parameters, namely colour, viscosity, free fatty acid (FFA) content and dielectric property, and to investigate changes in properties of mixtures of fully hydrogenated and non‐hydrogenated canola oils during deep‐fat frying of chicken nuggets. Proportions of hydrogenated oil to non‐hydrogenated oil used in the study were 0, 20, 40, 60, 80 and 100%. Chicken nuggets were fried at 190 °C. The relationships among quality parameters, frying time and oil type were investigated. RESULTS: Frying time and oil type had significant effects on all properties. First‐order kinetic equations were used to represent changes in colour, viscosity and FFA content. The rates of change of viscosity and FFA content were higher in non‐hydrogenated oil, whereas the rates of change of colour were similar in the different oils. Increasing the level of hydrogenated oil in the mixture resulted in only slight changes in quality parameters. CONCLUSION: Quality parameters, namely colour, viscosity, FFA content and dielectric property, of frying oil are significantly affected by frying time and hydrogenation level. Frying oil quality and stability can be adjusted by mixing hydrogenated and non‐hydrogenated oils. Copyright © 2008 Society of Chemical Industry  相似文献   

13.
The determination of frying oil quality using a chemosensory system   总被引:1,自引:0,他引:1  
Chemosensory systems are currently being introduced in the food industries for quality control and process monitoring. This study was conducted to determine the possibility of using a chemosensory system to differentiate among varying intensities of oil rancidity and investigate discrimination between good, marginal and unacceptable frying oils. Fresh, 1-day, 2-day used and discarded frying oils were obtained from a fast food restaurant in each frying cycle for 4 weeks. The oil samples were analysed using a quartz-microbalance-based chemosensory system. The discrimination between good, marginal and unacceptable frying oils with regard to rancidity was examined and the results were compared to their physico-chemical properties such as dielectric constant, peroxide value, and free fatty acid content. The different qualities of frying oils were successfully evaluated and discriminated using the chemosensory system. Good correlations (r from 0.87 to 0.96) were found between changes in physico-chemical properties of oil and the sensor signals.  相似文献   

14.
It is a challenging task to rapidly determine the quality of frying oils at various stages of frying. This study aims to evaluate the performance of eight different rapid test kits on three different types of oils, viz palm olein, cooking oil (a blend of palm olein, sesame oil and peanut oil) and sunflower oil. Two commonly consumed foods, French fries and chicken nuggets were selected as the frying food materials. Out of the eight test kits, five of them, namely FASafe™, 3M™ Low Range Shortening Monitor, Fritest®, Oxifrit-Test® and TPM Veri-Fry® were based on colorimetric reactions; whereas the other three test kits, namely Food Oil Monitor 310, Testo 265 and CapSens 5000 were based on dielectric constant. It was found that the test kits based on physical parameter provided more objective and valuable results as compared to those based on colorimetric reactions.  相似文献   

15.
生产加工与餐饮企业为降低成本需要合理重复使用煎炸油,为保证煎炸食品的安全性,有必要建立快速有效的检测方法,以便于企业对煎炸油品质进行监控。选用目前生产加工及餐饮企业广泛使用的12种煎炸油为监控对象,包括大豆油、棕榈油、高油酸菜籽油等7种单品油和5种不同组成的调和油,煎炸处理薯条、鸡块和鱼排3种常见快餐食品,试验每12 h取样检测煎炸油中的总极性组分含量(TPC),对比研究柱层析法及TESTO 270快速检测法的结果相关性。试验结果表明,使用快速检测仪检测样品TPC,当TPC20%时,其结果与柱层析法具有显著相关性(Pearson系数为0.744~0.984,P0.01),但当TPC20%时,相关性减弱(Pearson系数为0.553~0.929,P0.01),R~2值为0.149 2~0.863 2。当TPC介于20%至27%之间时,TESTO 270快速检测法的结果有3.6%假阳性,TPC大于27%时,假阴性结果比率为10%。本研究为TESTO 270快速检测法在煎炸油质量监控中的应用提供了参考。  相似文献   

16.
为了提供植物油在微波和射频等介电加热技术和通电加热技术中的应用基础数据,考察脂肪酸含量对植物油介电特性的影响,分别利用LCR阻抗测试仪和网络分析仪(同轴探针法)测量了4种植物油(橄榄油、自制橄榄油、橄榄调和油、大豆油)和5种脂肪酸(棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸)在低频段(1 000 Hz~2 MHz)和高频段(300~10 000 MHz)的介电特性。结果表明:低频下,植物油的介电常数比较稳定,其均值为(1.56±0.02),介电损耗随着频率的增加而下降,其中0.7 MHz时橄榄油具有最大的介电常数(1.67±0.00)和介电损耗(7.31±0.02);高频下,植物油的介电特性随着频率的上升而缓慢下降,4种植物油之间的介电特性的差异不显著(p0.05);低频下,在植物油中加入油酸后,植物油的介电常数和介电损耗呈现先上升后下降的趋势,而添加亚油酸呈现相反的趋势。添加脂肪酸会加快油脂的氧化反应。  相似文献   

17.
Butteroil, sunflower oil, olive oil, and a blend containing equal portions of the three oils were used for potato frying and examined periodically for oxidative stability. Analysis included measurements of polymers, cyclic monomers, the change in dielectric constant and volatile compounds. The blend exhibited greater stability than expected on the basis of the data obtained from the individual oils. In one frying experiment, for example, the polymers and cyclic monomers formed in the blended oil after 37 hr were 0.6% and 0.2%, respectively, as compared to calculated values of 1.8% and OS%, respectively. The higher stability of the blended shortening against oxidation appeared to reflect the presence in butteroil of a protective agent or agents sufficient to protect other less stable oils.  相似文献   

18.
C. Inoue    Y. Hagura    M. Ishikawa    K. Suzuki 《Journal of food science》2002,67(3):1126-1129
ABSTRACT: :
Suitability of the dielectric constant for real time and continuous evaluation of frying oil was investigated. Measurements of the dielectric capacitance, in the frequency range 1 kHz to 100 kHz, were made on soybean oil heated at several temperatures (180, 200, 220, and 240 °C) for a few d. Frequency dependence was also measured between 50 Hz and 30 MHz. The dielectric constant of the soybean oil increased with increase in the heating time, and was well correlated with acid value, density, and relative viscosity. Our equipment for measuring capacitance would be available for real time and continuous evaluation of frying oil quality in the food industry.  相似文献   

19.
The levels of β-sitosterol and total phytosterols were monitored in pre-fried potatoes during eight successive pan- and deep-frying sessions in five different commercial frying oils (virgin olive oil, sunflower oil, palm oil, cottonseed oil and vegetable shortening oil). The amount of these constituents that were transferred from the frying oils to the potatoes at the end of each frying session was determined prior and after frying by GC/FID. Except for the potato enrichment with phytosterols, the kinetics of the destruction of β-sitosterol and total phytosterols, mainly due to thermal oxidation of the oils, were evaluated for each of the five different types of oil. The experiments showed that in most cases the destruction of both β-sitosterols and total phytosterols followed first order kinetics with quite good correlation coefficients (R>0.92) and the reaction constant k was found to be at the range of 0.004 - 0.028 min-1. Concerning the absorption of the two types of phytosterols in the fried potatoes during frying, they were found to be at the range (average) of 0.4-27% of their initial content in the oil at the beginning of each frying process (eight frying processes/session), depending on the type of oil and the constituent.  相似文献   

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