Kinetics of Potato Color and Texture Development during Baking, Frying, and Microwaving with the Addition of Liquid Smoke

ABSTRACT:  The rate of color and texture development in par-fried French fries coated with liquid smoke and thermally processed was determined. Liquid smoke containing 8% to 11% carbonyls was diluted to 30% and applied to 1 side of French fries at 0%, 1%, 3%, or 5% by weight. The fries were immersion fried at 190.6 °C for 4 min, microwaved (900 watts) for 4 min, or baked at 190.6 °C for 20 min. Color and texture measurements were recorded at intervals during processing. Liquid smoke increased the rate of browning in French fries. Browning followed pseudo zero-order kinetics, with the a value, Browning index, and total change in color (ΔE) showing the best fit. When liquid smoke was added in high concentrations the reaction rate did not increase as more liquid smoke was added because the carbonyls were no longer limiting the rate of Maillard browning. The rate of color development in French fries was also affected by the thermal processing method. Frying developed color at the fastest rate, followed by microwaving and baking. Although liquid smoke increased the rate of color development in French fries, it did not affect French fry texture. Through sensory testing, it was determined that liquid smoke can be used to improve the color of microwaveable French fries without affecting French fry flavor or texture.     

A Fraction Conversion Kinetic Model for Thermal Degradation of Color in Red Chilli Puree and Paste

The kinetics of degradation of color was evaluated using a fraction conversion model during thermal treatment of red chilli puree at 60, 70, 80 and 90°C (up to 20 min) and storage of red chilli paste at 5, 25 and 37°C (up to 6 mo). Red chilli puree was subjected to heat treatment at different temperatures in a well-stirred water bath. Test samples were removed from the bath at selected time intervals (0-20 min after come-up), cooled immediately and analysed for color using a Hunterlab colorimeter. Chilli paste was prepared by a standard formulation by adding common salt (8%) and the required volume of citric acid to bring the pH to 4.0. The paste was thermally processed at 85°C for 15 min, filled into glass bottles and stored at selected temperatures for 6 mo. Red chilli color was expressed as a tristimulus combination value (L·a·b) as well as the total color difference (ΔE). The fraction conversion model adequately described the kinetic changes in both color values during thermal treatment of puree and storage of puree. The process activation energies were 24.2 and 24.8 kJ/mol, respectively, for ΔE and L·a·b during the thermal treatment, and during the storage the respective values were 24.1 and 25.0 18;kJ/mol. Up to the end of the 6-mo storage, the paste was microbiologically stable with no major changes in other physico-chemical characteristics.     

Thermal kinetics of color degradation of mulberry fruit extract

The effects of temperature and pH on color degradation kinetics of the mulberry fruit extract were investigated. The absorbance at 510 nm was decreased with increase of heating time, but that at 420 nm was increased with the increase of heating time at 100 degrees C. The change of the browning index (A510/A420) was increased with increase of pH and was lower at pH 2.0 than that at pH 5.0. The browning index variation was adequately described by both the first-order and the zero-order kinetic. However, the zero-order kinetic model was proposed because of the better fit. According to the Arrhenius model, the activation energies for the browning index in the range of 80-100 degrees C for the four different pH values were 30.68 kJ/mol for pH 2.0, 35.87 kJ/mol for pH 3.0, 42.67 kJ/ mol for pH 4.0, and 43.49 kJ/mol for pH 5.0.     

Digital image analysis of cigarette filter staining to estimate smoke exposure.

Sufficient variation exists in how people smoke each cigarette that the number of cigarettes smoked daily and the years of smoking represent only crude measures of exposure to the toxins in tobacco smoke. Previous research has shown that spent cigarette filters can provide information about how individuals smoke cigarettes. Digital image analysis has been used to identify filter vent blocking and may also provide an inexpensive, unobtrusive index of overall smoke exposure. A total of 1,124 cigarette butts smoked by 53 participants in a smoking topography study were imaged and analyzed. Imaging showed test-retest reliability of more than 95% among those smoking their own brand. Mean color scores (CIELAB system) showed acceptable stability (>.60) across days, paralleling the basic stability of smoking topography measures across waves. A principal components scoring showed that center tar staining, edge tar staining, and their interaction were significantly related to total smoke volume, accounting for 73% of the variation. Estimated smoke volume was a significant predictor of salivary cotinine when accounting for cigarettes smoked per day. These data suggest that digital image analysis of spent cigarette butts can serve as a reliable proxy measure of total smoke volume.     

Functionality of liquid smoke as an all-natural antimicrobial in food preservation

The smoking of foods, especially meats, has been used as a preservation technique for centuries. Today, smoking methods often involve the use of wood smoke condensates, commonly known as liquid smoke. Liquid smoke is produced by condensing wood smoke created by the pyrolysis of sawdust or wood chips followed by removal of the carcinogenic polyaromatic hydrocarbons. The main products of wood pyrolysis are phenols, carbonyls and organic acids which are responsible for the flavor, color and antimicrobial properties of liquid smoke. Several common food-borne pathogens such as Listeria monocytogenes, Salmonella, pathogenic Escherichia coli and Staphylococcus have shown sensitivity to liquid smoke in vitro and in food systems. Therefore liquid smoke has potential for use as an all-natural antimicrobial in commercial applications where smoke flavor is desired. This review will cover the application and effectiveness of liquid smoke and fractions of liquid smoke as an all-natural food preservative. This review will be valuable for the industrial and research communities in the food science and technology areas.     

Use of time-temperature integrators and predictive modeling to evaluate microbiological quality loss in poultry products

The purpose of this study was to characterize the kinetics of the spoilage process of chicken drumsticks in order to evaluate the application of an enzyme process-based time-temperature integrator (TTI) as a continuous quality monitor of poultry products. Shelf life studies were conducted at several temperatures (3 to 20 degrees C) to characterize (i) the poultry spoilage process as a function of total aerobic bacteria and Pseudomonas species populations and (ii) the TTI chroma response function. Two types of poultry products were examined: ice-packed and chill-packed drumsticks. An enzyme-based TTI with a color change response from green to yellow was used. Activation energies for each of the poultry products and each of the bacterial populations were as follows: 21.8 +/- 1.6 kcal/mol (ca. 91.2 +/- 6.7 kJ/mol) for ice-packed drumsticks and total aerobic population, 18.8 +/- 4.5 kcal/mol ca. 78.7 +/- 18.8 kJ/mol) for ice-packed drumsticks and Pseudomonas spp., 17.0 +/- 2.3 kcal/mol (ca. 71.1 +/- 9.6 kJ/mol) for chill-packed drumsticks and total aerobic population, and 14.1 +/- 3.6 kcal/mol (ca. 59.0 +/- 15.1 kJ/mol) for chill-packed drumsticks and Pseudomonas spp. The activation energy calculated for the TTI, 19.1 +/- 1.8 kcal/mol (ca. 79.9 +/- 7.5 kJ/mol), was determined to be adequately close to that of the poultry spoilage process to make effective quality predictions possible. Initial bacteria levels on the chicken drumsticks were uniform and not judged as important limiting factors in the application of TTIs to poultry products. Because the poultry spoilage process was reasonably characterized on the basis of Arrhenius kinetics, there is further need to conduct validation studies to determine the ability of TTIs to provide a continuous quality monitoring system.     

基于扩散型时间-温度指示器表征鲜银耳贮藏过程品质变化

为了研究扩散型时间-温度指示器(Time-Temperature Indicator,TTI)能否表征鲜银耳贮藏过程中品质变化,分别研究了不同贮藏温度(5、13、17、23 ℃)下,扩散型TTI的颜色变化和鲜银耳品质(失重率、可溶性糖含量及丙二醛含量)变化情况,通过化学品质动力学模型及Arrhenius方程分别计算扩散型TTI颜色变化和鲜银耳品质变化的活化能Ea,并将扩散型TTI颜色变化的活化能与鲜银耳品质变化的活化能进行比较,从而评估扩散型TTI与鲜银耳的品质变化的匹配性。研究结果表明,贮藏温度及贮藏时间对扩散型TTI颜色变化和鲜银耳品质变化均有影响,且贮藏温度越高,扩散型TTI由白色变为蓝色的速度越快,鲜银耳也越容易腐烂。通过化学品质动力学模型及Arrhenius方程计算得出扩散型TTI的活化能E_a值为36.1135 kJ/mol,鲜银耳失重率、可溶性糖含量及丙二醛含量的活化能分别为53.3144、53.3368、43.9744 kJ/mol,扩散型TTI与鲜银耳品质变化的活化能差值<25 kJ/mol,因此可以将此扩散型TTI用于鲜银耳贮藏过程中的品质监控。     

不同贮藏温度下两种发酵香肠品质变化及货架期预测模型的建立

对玫瑰低硝半干发酵肠(M)和传统半干发酵肠(P)在3个温度(4、25、35℃)贮藏过程中的品质变化进行了评价,并运用动力学和Arrhenius方程建立了两种发酵肠货架期预测模型.研究表明,温度对两组香肠的红度值和质构特性影响较大,在贮藏期间,各贮藏温度下的酸价、挥发性盐基氮(total volatile basic n...     

LC-MS/MS法检测卷烟滤嘴截留的烟气TSNAs

为了解滤嘴对烟草特有亚硝胺(TSNAs)的截留效率,采用液相色谱-串连质谱(LC-MS/MS)法测定了30种卷烟样品滤嘴中截留的烟气TSNAs:NNN、NAT、NNK、NAB。用0.1mol/L醋酸铵水溶液萃取烟蒂滤嘴,萃取液过OASIS MCX小柱,用50%(体积分数)甲醇洗脱,洗脱液直接进行LC-MS/MS分析,分析条件为:色谱柱:Waters Symmetry Shield TM RP18柱,柱温:65℃;流动相:50%甲醇水溶液(水中含0.1%醋酸),等度洗脱,流速0.25mL/min。结果显示:①NNN、NAT、NNK和NAB的检测限分别为0.7、0.3、0.6和0.4ng/支,回收率96.0%～103.5%,相对标准偏差(RSD)均小于8%;②NNN、NNK、NAT、NAB的滤嘴截留率分别在16.67%～43.05%、30.51%～55.97%、16.19%～45.00%和41.68%～49.08%范围内;③混合型卷烟滤嘴对NNN、NAT的截留效率要高于烤烟型卷烟,而对NNK、NAB和TSNAs总量,混合型卷烟滤嘴和烤烟型卷烟滤嘴的接近;④醋酸纤维滤嘴对NNK、NAB的截留率与聚丙烯纤维滤嘴相当,...     

发酵酸肉煮制过程品质动力学研究

利用动力学分析发酵酸肉在70~80℃水浴加热过程中成熟因子(色泽、剪切力)及过热因子(水分活度、水分含量)动力学变化过程。结果表明:随着加热温度的升高,发酵酸肉成熟因子(色泽、剪切力)及过热因子(水分活度、水分含量)变化均符合一级动力学方程,其中亮度值的Z值为63.751℃,Ea值为4.016kJ/mol;红度值变化Z值为35.500℃,Ea值为4.029kJ/mol,黄度值变化Z值为32.459℃,Ea值为4.031kJ/mol。剪切力Z值为102.070℃,Ea值为4.047kJ/mol。水分活度的Z值为55.118℃,Ea值为3.643kJ/mol。水分含量Z值为-2.366℃,Ea值为4.034kJ/mol。发酵酸肉煮制过程成熟因子色泽红度值、黄度值的Z值小于水分活度Z值,成熟品质因子亮度值、剪切力的Z值大于过热品质因子水分活度、水分含量的Z值,亮度值、剪切力值的变化与优化烹饪条件结论相反,说明发酵酸肉加热过程中其成熟及过热因子均存在优化空间,可以通过优化加热条件进一步改善发酵酸肉品质变化。     

响应面优化离子液体超声辅助提取黄花菜总黄酮工艺研究

采用离子液体超声辅助提取黄花菜中总黄酮,以单因素试验为基础,利用Box-Behnken优化提取工艺.结果 表明,以离子液体为提取溶剂提取黄花菜总黄酮的最佳条件为0.8 mol/L[C6mim]Br(1-己基-3-甲基咪唑溴化盐)水溶液,液料比20∶ 1(mL/g),提取温度和时间分别为60℃和30 min,黄花菜总黄酮...     

Degradation kinetics of pomegranate juice phenolics under cold and warm sonication process

In the present study, the degradation kinetics of the phenolics present in pomegranate juice-(PJ) under the conditions of thermosonication were evaluated along with the formation of brown pigments. The results highlighted that over thermosonication had an adverse effect on PJ-phenolics. The first-order degradation kinetic was determined as the best model for PJ-phenolics, while polymeric color rate values regarding the brown pigment formation had a linear tendency. The kinetic results indicated that the degradation rate of the anthocyanins was remarkably higher than the ellagic acid degradation rate. Ea-values for the degradation of the mono-glucoside anthocyanins (8.85–10.59 kJ/mol) were also calculated higher than the di-glucoside anthocyanins (5.34–6.31 kJ/mol), whilst the highest of Ea-value was determined for ellagic acid degradation-(16.28 kJ/mol). Overall, the study findings have suggested that low ultrasound energy density and temperature help to minimize the loss of the phenolics playing a critical role in general and nutritional qualities of PJ.     

磷石膏转化法制硫酸钾反应过程动力学研究

文章对磷石膏转化法生产硫酸钾第二阶段反应过程中各影响因素进行了研究 ,在液膜扩散控制下 ,确定了其动力学方程 :1- ( 1-XB) 23=kt。经实验数据关联可得反应的活化能为 :6 889kJ/mol。反应速率常数与温度的关系为 :k =3 .42 1exp - 6889RT 。动力学模型经检验 ,其置信度 >95 %。     

Thermal Degradation Kinetics of Carotenoids and Visual Color of Papaya Puree

The degradation kinetics of carotenoids and visual color of papaya puree were investigated at selected temperatures (70 to 105°C). The concept of fractional conversion was applied to determine the kinetic parameters. The degradation of papaya color was based on change of Hunter a and b values and it was found that combination of Hunter (a × b) value adequately represented thermal color change. Degradation of carotenoids and visual color followed first order reaction kinetics. Dependence of the rate constant followed the Arrhenius relationship. The process activation energies for carotenoids and visual color were 20.56 and 32.59 kJ/mol respectively. Higher activation energy value indicated greater temperature sensitivity of visual color as compared to carotenoids. The degradation of pigment and visual color varied linearly. Visual color could therefore be used for on‐line quality control of papaya puree.     

响应面法优化福林酚法测定冬枣中总酚含量

该研究优化福林酚法测定冬枣中总酚含量的工艺条件,以福林酚试剂浓度,20%碳酸钠用量以及显色温度作为单因素,以总酚含量作为指标,在单因素试验基础上利用响应面分析法对测定条件进行优化。结果表明,总酚测定最佳工艺条件为:福林酚试剂浓度0.8 mol/L、20%碳酸钠浓度的用量为0.6 mL、反应温度设40℃。在此条件下测得的冬枣总酚平均值为501±3.58μg/mL,与预估值509.498μg/mL的吻合度高达98.4%。经验证该工艺条件准确且稳定,确定了福林酚法测定冬枣中的总酚含量所用试剂的标准。     

大蒜素在正戊烷和乙醇中的分解动力学研究

研究了大蒜素在正戊烷、乙醇溶剂中的分解动力学过程,拟合得到了动力学参数：大蒜素在正戊烷、乙醇溶剂中的分解活化能分别为56.0、72.0 kJ/mol,指前因子分别为9.2×105、1.5×106。采用B3LYP方法,在6-31+G(d,p)基组下计算了大蒜素与正戊烷、乙醇的相互作用能分别为1.12、31.18 kJ/mol,说明大蒜素与乙醇分子间存在较强的相互作用;采用自然键轨道理论分析了以乙醇为溶剂的体系中电子供体(Donor)轨道、电子受体(Acceptor)轨道以及它们之间相互作用的稳定化能,结果表明大蒜素分子中的氧原子的孤对电子O(13)对乙醇分子的羟基（O(21)-H(20)）的反键轨道稳定化能为45.45 kJ/mol,说明大蒜素与乙醇分子产生较强的氢键作用,分散了大蒜素分子中的氧原子上的负电荷,导致分子内质子转移能量升高,因而大蒜素在乙醇中具有更高热稳定性。     

SHELF-LIFE MODELING OF SWEETENED CONDENSED MILK BASED ON KINETICS OF MAILLARD BROWNING

Nonenzymatic browning and related changes were monitored in commercial sweetened condensed milk stored at 7, 15, 30, 45 and 55C. Darkening of the color measured in terms of absorbance (100 - reflectance percent) followed zero-order kinetics, the apparent activation energy (E_a) being 45.2 kJ/mol at 7–30C and 139.9 kJ/mol at > 30–55C. Hydroxy-methyl-furfural (HMF) showed a first-order increase, the associated E_a values being smaller than those for absorbance. The pH exhibited a linear decline after a small initial rise at 30C and below. As browning progressed, the coffee whitening ability of the product decreased along zero-order kinetics. The Q₁₀ values for these variables ranged from 1.21 to 1.84 for temperatures up to 30C and were nearly 2–3 times higher above 30C. The sensory color score was negatively correlated with absorbance. The linear regression of color score on absorbance and the temperature dependence of the latter as expressed by Arrhenius relationship were combined into a mathematical model which could be useful in predicting the product's shelf-life.     

胡萝卜中类胡萝卜素的提取动力学

使用抗坏血酸和2,6-二叔丁基-4-甲基苯酚保护剂,以石油醚-丙酮（体积比4∶1）混合液为提取剂,分别用水浴直接提取法、超声辅助提取法和微波辅助提取法从胡萝卜粉中提取类胡萝卜素。采用不同温度和原料粒度进行从胡萝卜粉中提取类胡萝卜素的提取动力学实验。结果表明,水浴法和超声辅助法是符合反应-内扩散控制的动力学模型,所得提取动力学方程分别为：1）水浴法：y=0.009 9t＋0.110 7（R2=0.920 9,30 ℃）、y= 0.018 6t＋0.096 1（R2=0.893 7,40 ℃）、y=0.018 2t＋0.088 6（R2=0.965 7,45 ℃）;2）超声辅助法：y=0.001 1t＋0.080 9（R2= 0.917 9,30 ℃）、y=0.001 6t＋0.043 9（R2=0.978 8,40 ℃）、y=0.001 8t＋0.039（R2=0.964 2,45 ℃）。表观活化能分别为Ea（水浴）=－26.825 1 kJ/mol和Ea（超声）=－35.196 5 kJ/mol。而微波辅助法则是符合混合控制的动力学模型,其方程为y=0.027 5t＋0.344 6（R2=0.972 3,30 ℃）、y=0.031 9t＋0.426 5（R2=0.868 9,40 ℃）、y=0.058 7t＋0.275 1（R2=0.973 4,45 ℃）,表观活化能为E a（微波）=－36.105 2 kJ/mol。通过水浴法考察原料粒度对提取动力学的影响,结果表明原料粒度对提取速率和提取率的影响程度是60～80 目＞40～60 目＞20～40 目,即粒度越细越有利于类胡萝卜素的提取。     

维生素C在婴儿配方乳粉加工、冲调模拟体系中的热降解动力学

对婴儿配方乳粉在加工、冲调过程中氧化型维生素C(DHAA)、还原型维生素C(AA)及总量维生素C(AA+DHAA,以VC表示)的热降解动力学进行研究。结果表明:加工模拟体系中,AA及VC符合动力学一级反应,活化能分别为46.49 kJ/mol和39.69 kJ/mol。冲调模拟过程中,温度对AA和VC的降解符合零级反应模型,对DHAA的降解符合一级反应模型,反应活化能分别为16.71,19.50,12.04 kJ/mol。     

烟熏对肉制品风味及安全性影响研究进展

烟熏是一种利用木材不完全燃烧产生的熏烟对食品进行熏制的加工方法。熏烟不仅能提升肉制品的感官特性,还能对肉制品起到防腐保鲜的作用。通过改良传统烟熏方式,开发出更加科学的烟熏技术,如液态烟熏和水蒸气渗透烟熏,能够有效提高烟熏肉制品的安全性,并进一步改善烟熏肉制品的风味和色泽。本文综述了烟熏的发烟与熏制原理、影响因素及熏烟成分组成,着重介绍了烟熏技术对肉制品风味及安全性的影响,并对其发展趋势进行了展望。