Evaluation of Pasta Thermal Treatment By Determination of Carbohydrates, Furosine, and Color Indices

The drying process of pasta plays a crucial role in assuring its final quality, since the operational conditions of this process may imply thermal and mechanical damage that also affect final product yield. In this work, independent analyses on furosine, carbohydrates, and color indices (red, yellow, and lightness) have been conducted on pasta samples produced by an Italian pasta factory in order to correlate the examined parameters with pasta drying process. The investigation has been focused on pasta samples having different shapes in order to evaluate how the considered parameters are affected by the specific thermal process scheduled for each pasta format. The same analyses were also performed on semolina used for each pasta sample production, with the aim of verifying whether furosine amount, color indices, and maltulose change in relationship with Maillard reaction (MR) occurring during the drying process. Maltulose presence has been evaluated in semolina for the first time. In addition, the study has been extended to commercial pasta samples of different qualities; a Principal Component Analysis (PCA) has also been conducted to combine together all observed data with the aim of proposing an overall quality index. Finally, a statistical model based on chemical and color parameters as independent variables was successfully developed (R ²?=?0.990) by means of a multiple linear regression (MLR) analysis to predict commercial pasta cook values and drying cycles as consequences.     

Intrinsic Thermal Conductivity of Starch: A Model-independent Determination

Effective thermal conductivities of two-phase mixtures of potato or soluble starch granules with pure liquids or aqueous solutions (thermal conductivities in the range 0.169–0.602 W.m^?1.K^?1) were measured at 18.5±2.2°C using the steady state method. Measured values were compared with the thermal conductivities of the liquids and the results indicated a range of 0.38–0.40 W.m^?1K^?l for intrinsic thermal conductivity. Similar measurements, at temperatures up to 50°C for soluble starch (to assess the temperature dependence of the intrinsic thermal conductivity) indicated no significant change over the range of temperature studied for mixtures with pure liquids.     

应用红外热成像技术测试黄鼬毛皮的保温性能

以黄鼬为研究对象,在自行研制的毛皮导热性测试平台上,拟定3种试验方案,用FILRT400热像仪拍摄不同室温、不同部位、不同性别的毛皮样本,通过配套软件分析毛皮表面红外热像图的温度分布。结论:入冬室温下毛皮的保温能力最强,秋季其次,夏季最低;颈部、背部、臀部的较胸部、腹部的强,且自吻端至尾基渐增;雄性的较雌性的强。红外热像测温技术不接触毛皮,测量结果直观形象,能定性地分析不同部位、不同性别毛皮保温性的差异。     

基于红外热像技术对内衣保暖性能的测试与评价

针对内衣保暖性能测试方法的不足,探求一种新的测试及评价的方法,利用红外热像仪对不同种类内衣的保暖性能进行测试与评价.结果表明:暖绒保暖内衣的保暖性能最佳,并探讨了红外测试技术在服装热舒适性上的应用方法及其优越性.     

Design,Fabrication and Evaluation of a Plantain Roaster

Roasted plantain (boli) is a delicacy in Nigeria. The conventional method of processing this food is crude, stressful and unhygienic. In this work, an electric roaster capable of roasting twenty-one plantain fingers per batch was designed, fabricated and tested. The roaster had two electric heating elements (one at the top and the other at the base of the roaster) supplying power at the rate of 2.4 kW In addition, moisture release pipe and a temperature regulator were incorporated. The roaster was used to produce plantain, product was compared with roasted plantain prepared using the conventional method to test acceptability. At a p < 0.05 significance level, it was observed that the samples had no significant difference in appearance, aroma, texture and overall acceptability. However, sample at the upper layer of the roaster was significantly different from the other samples in taste. Generally, sample roasted in the lower part of the roaster was most preferred.     

Food Quality Evaluation using Model Foods: a Comparison Study between Microwave-Assisted and Conventional Thermal Pasteurization Processes

Thermal process optimization has focused on traditional sterilization, with limited research on pasteurization or microwave-assisted thermal processing. Model foods have been developed as quality evaluation tools for thermal pasteurization processes, but there are no comprehensive studies demonstrating how these model foods could be used to evaluate and compare the resulting food quality after different pasteurization processes. The aim of this study was to develop a methodology using image and quantitative analyses for quality evaluation of pre-packaged food pasteurized using a microwave-assisted pasteurization system (MAPS) and traditional hot water method. Four pasteurization processes (MAPS and hot water method at 90 and 95 °C) were designed to have an equivalent accumulated thermal lethality at the cold spot of at least 90 °C for 10 min to control nonproteolytic Clostridium botulinum spores. Color-based time-temperature indicators in mashed potato and green pea model foods were quantified using image analysis. Results showed that median color values were useful in assessing overall color change, and interquartile range was an indicator of burnt areas. MAPS 95 °C was the best process because it had the smallest hot spot cook values and the least color change, while the 90 °C hot water process was the worst. Model foods and image analysis techniques were useful pasteurization process quality evaluation tools and made it possible to visualize the potential food quality change volumetrically, throughout a food package. In the future, these tools could be combined with computer simulations to optimize the quality of pilot-scale and industrial MAPS or conventional pasteurization processes.     

Immobilized Peroxidase: A Potential Bioindicator for Evaluation of Thermal Processes

The heat-stable fraction of covalently immobilized peroxidase on/in porous glass beads in an environment of dodecane was studied as a bioindicator for evaluation of thermal processes under conditions of pasteurization. The verified bioindicator had a z value of 10.1°C and a Dref (at 70°C) of 22 min. At processing temperatures of 70°C and 80°C, the lethalities (F)_bio as read from the bioindicator agreed very well with the target Ft^10.0 values calculated from the time temperature data according to the general method.     

Evaluation of a Modified AOAC Determination for Thiamin and Riboflavin in Foods

Modifications of the AOAC thiamin and riboflavin methods allow determination of the two vitamins from aliquots of a single food sample with alternatives to obsolete or dangerous reagents. Mylase 100, an α-amylase enzyme which hydrolyzes thiamin esters, was shown to be effective at releasing thiamin in 3 hr over a pH range of 3.5–5.5, at 35 and 42°C. In thiochrome extraction, anhydrous isopropanol can be substituted for isobutanol, a suspected carcinogen.     

暖体假人恒温控制软件设计

介绍了暖体假人恒温控制软件的设计思想、主要功能 ,重点解决了暖体假人测试系统信号检测与动态连接库的设计、实时热流调控、数据库与数据绑定控件的无缝连接和数据管理等关键技术问题。     

Determination of Thermal Process Schedule for Acidified Papaya

The pH of papaya varies from 4.2-5.65 and is required to be lowered to enable processing at atmospheric pressure. A thermal process has been evolved on the basis of inactivation of pectinesterase (PE), the heat resistant enzyme naturally present. The values for thermal inactivation of PE in pulp were F^26.8₂₁₂= 1.04 and D²⁷₂₁₂= 0.39 at pH 4.0. In the syrup homogenate of 20% TSS, the values were F^27.6_207.3= 1.00 and D²⁹_207.3= 0.53 at PH 3.8, and F^27.2₂₁₂= 1.23 and D^27.5₂₁₂= 0.8 at pH. 4.0. These F values in syrup homogenate were equivalent to 1.88D at pH 3.8 and 1.5 3D at pH 4.0. In commercial canning, a 2.5D process at pH 3.8 and 2.0D process at pH 4.0 which are equivalent to the F values of 1.33 and 1.31, respectively, are recomended. Using these F values, process times for different processing conditions were calculated by graphical method and compared with values found by three different procedures of the formula method. The thermal process, thus evolved on the basis of enzyme inactivation, resulted in a safe and acceptable product.     

In Situ Degradation Kinetics: Evaluation of Rate Determination Procedure

In situ digestion profiles from dry matter, acid detergent fiber, neutral detergent fiber from alfalfa hay, and dry matter from orchardgrass hay were selected to compare methods to describe kinetically degradation rates. The four methods were 1) least squares regression of logarithmic-transformed residuals without correction for ruminally undegradable residue, 2) method 1, with correction for undegradable residue, 3) curve peeling, and 4) nonlinear iterative least squares regression.Not correcting data sets for undegraded residue resulted in rate constants for all chemical components of forage approximately one-third as fast compared with results correcting each fermentation point. Neutral detergent fiber of alfalfa hay and dry matter from orchardgrass hay exhibited single component linear degradation profiles; however, alfalfa hay dry matter and acid detergent fiber each exhibited two distinct linear component profiles. Methods 2, 3, and 4 estimated the following rate constants for alfalfa hay dry matter and acid detergent fiber: 7.5, 22.3, and 17.4%/h and 4.4, 25.2, and 8.8%/h, respectively. The nonlinear method tended to underestimate lag and potential extent of degradation to achieve a best fit curve for alfalfa acid detergent fiber and tended to overestimate potential extent of degradation when one linear component existed. One specific method may not be adequate to describe all degradation profiles.     

Sorption Isosteric Heat Determination by Thermal Analysis and Sorption Isotherms

A procedure based on thermal analysis thermogravimetry (TG) and differential-scanning calorimetry (DSC) was examined to compute isosteric heat of sorption for water. DSC measurements on samples with different moisture content allowed determining enthalpy variations due to water vaporization. Thermogravimetries performed on the same samples enabled a link to be made between enthalpic measurements and weight losses and thus compute isosteric heats. The procedure was applied to cauliflower and potato starch. From equilibrium isotherms by applying the Clausius-Clapeyron equation, the isosteric heats of sorption were calculated. The comparison of the values obtained through both procedures showed a good agreement.     

用热分析技术评价小麦新鲜度的研究

本文利用热分析技术（TG、DSC、DMA）对小麦储藏过程中生物大分子物质的变化情况进行了探讨。TG法主要了解小麦的热稳定性，DSC法探索了小麦籽粒中大分子晶体区域的热量变化情况，测试结果表明：Tp随储藏时间的增加而增加，△H随储藏时间的增加而减少；DMA法讨论了小麦中非晶区大分子的热量变化情况，结果显示：Tg与储藏时间呈多项式的关系，相关系数为0.842；Te-To与储藏时间线性相关，相关系数0.956。通过测定Te-To，即可根据Y＝－1.931X 116.5算出小麦储藏时间，进而评价其新鲜度。     

一种用于汞检测的三联吡啶钌配合物的分子设计与合成

设计合成一种具有延长共轭体系的三联吡啶钌配合物：4’-（p-硝基苯基）-2,2’6’∶2’’-三联吡啶基-三异硫氰 基钌Ru(tpy)(NCS)3,该配合物与汞离子作用后由墨蓝色变为粉红色,如以肉眼可见粉红色作为检测灵敏度,则对汞 离子的检测限约为0.03 μg/g。通过密度泛函理论B3LYP方法优化得到了Ru(tpy)(NCS)3以及Ru(tpy)(NCS)3与Hg2+离子 结合形成的配离子[Ru(tpy)(NCS)3·HgCl]+的几何构型,通过对其前线分子轨道成分的分析,探讨钌配合物作用于 汞离子检测的基本机理。     

抗氧化剂的抗氧化活性的测定方法及其评价

把影响抗氧化剂氧化活性测定的主要因素分为三个大的方面：Ａ．底物或基质体系;Ｂ．加速方法;Ｃ氧化诱导期终点测定方法。系统研究和论述了抗氧化活性的测定及评价方法,并对不同方法进行了综合比较与评价。     

Solid Food Thermal Conductivity Determination at High Temperatures

Thermal conductivity of carrots and potatoes was measured using a line heat source probe adapted for measurements to 130°C. Fastest response and rapid attainment of linearity in temperature rise vs In time plots, were obtained with a silicone oil-filled probe with an uninsulated thermocouple junction. Custom designed electronics to amplify thermocouple output, and computer control of measurements, data acquisition and analysis resulted in 0.4% data repeatability (two standard deviations) for calibration standards. Thermal conductivity of carrot and potato vs temperature agreed well with the published volume fraction model for multi-component foods.     

Evaluation of Structural,Tensile and Thermal Properties of Banana Fibers

Recognizing the importance of properties of the plant fibers for their use in polymeric composites and nonavailability of data on tensile, thermal, and other properties of banana fibers of Karnataka (India), a study was undertaken with the objective of determining some of these properties. This article presents determination of structural aspects of the fibers by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques; obtaining stress-strain curves and tensile properties by tensile testing; finally, thermal properties by differential scanning calorimetry and thermogravimetric analysis. FTIR spectrum of banana fibers showed aromatic character, while XRD results indicated the fiber to have mainly the cellulose I structure and crystallinity index of 52%. Thermal-degradation details of fiber samples were revealed by thermal studies. Stress-strain curves of banana fibers suggested their brittle nature with moderate values of tensile strength, but low percentage elongation. Weibull analysis of obtained tensile strength values revealed variation of “characteristic strength” values from 3800 MPa at 99% reliability to 22,700 MPa with 0.01% reliability. Morphology studies revealed the number of defects along the length of the fiber, while fractured surface exhibited flat surface with intracellular fractures clearly indicating brittle nature of the fiber.