Determination of Sprout-Damaged Barley Using Thermal Imaging

Pre-harvest sprouting is a major problem associated with cereal grains which results in lowering of end use quality. Pre-harvest sprouting affects the malting quality of barley.  The common methods to determine sprout damage are falling number, stirring number and amylograph peak viscosity, but these methods are time consuming.  There are other methods such as near infrared hyperspectral imaging and soft-x ray analysis which are still in the research stage.  Infrared thermal imaging technique to detect sprout damage is based on determining the changes in surface temperature distribution of grain which depends on the heat emission.  An infrared thermal camera was used in this study to determine whether sprout-damaged barley could be detected from healthy barley.  The results were analyzed using statistical and artificial neural network classifiers.  The classification accuracies were 78.7%, 78.9% and 88.5% for healthy; and 87.0%, 87.5% and 87% for sprouted kernels, using linear discriminant analysis, quadratic discriminant analysis and artificial neural network, respectively.  The results of the study show that thermal imaging has potential to determine sprout damage to barley.Keywords: grain, barley, sprout-damaged, thermal imaging, classification, Canad

Colour and rheological properties of non-conventional grapefruit jams: instrumental and sensory measurement

Alternative methods with which to obtain grapefruit jams have been applied. These include the use of osmotic dehydration (OD) and/or microwave energy (MW), as an alternative to conventional heating, and the incorporation of bamboo fibre together with pectin in order to increase the jam's consistency. Colour, consistency and rheological behaviour were measured and sensory evaluation was carried out to compare product quality. When compared to the fresh fruit, the greatest colour changes took place in those jams processed by MW and conventional heating, both of them showing lower L*, a*, b* and chrome values than the rest of the samples obtained by applying osmotic dehydration. By adding bamboo fibre, the colour of OD samples approaches that of fresh fruit. The higher yield stress, greater consistency and more viscoelastic behaviour was displayed by jams obtained by combining OD and MW processes. In the sensory analysis, the judges awarded this sample a better score. The sensory attribute product coverage in mouth was closely related to viscosity at a shear rate of 120 s(-1) and consistency. (C) 2013 Elsevier Ltd. All rights reserved.Igual Ramo, M.; Contreras Monzón, CI.; Martínez Navarrete, N. (2014). Colour and rheological properties of non-conventional grapefruit jams: instrumental and sensory measurement. Food Science and Technology. 56(1):200-206. doi:10.1016/j.lwt.2013.10.038S20020656

Impact of temperature on lethality of kiwifruit puree pasteurization by thermal and microwave processing

The use of pasteurization units (PU) as a measure of the lethal effect of processes was proposed with the aim of comparing conventional and novel thermal technologies. Kiwifruit puree was subjected to microwave (1000 and 900 W) and conventional (97 C) heating. Processing conditions of the treatments were chosen to simulate a pasteurization treatment. The temperature profiles of the samples during processing were recorded at different positions. The coldest and hottest spots of the product were identified and the associated PU numbers were calculated. A significantly (p < 0.05) higher thermal load was necessary in order to stabilize the kiwifruit puree under conventional (19.27 min) than microwave heating mode (0.003e8 min) at any of the conditions studied. The higher effectiveness of microwave heating could be attributed to non-thermal effects associated with this technology.The authors thank the Ministerio de Educacion y Ciencia for the financial support given through Projects AGL 2010-22176 and AGL 2010-22206-C02-01 and the grant awarded to the author Maria Benlloch.Benlloch Tinoco, M.; Martínez Navarrete, N.; Rodrigo Aliaga, MD. (2014). Impact of temperature on lethality of kiwifruit puree pasteurization by thermal and microwave processing. Food Control. 35(1):22-25. https://doi.org/10.1016/j.foodcont.2013.06.035S222535

Development of a Rapid Soil Water Content Detection Technique Using Active Infrared Thermal Methods for In-Field Applications

The aim of this study was to investigate the suitability of active infrared thermography and thermometry in combination with multivariate statistical partial least squares analysis as rapid soil water content detection techniques both in the laboratory and the field. Such techniques allow fast soil water content measurements helpful in both agricultural and environmental fields. These techniques, based on the theory of heat dissipation, were tested by directly measuring temperature dynamic variation of samples after heating. For the assessment of temperature dynamic variations data were collected during three intervals (3, 6 and 10 s). To account for the presence of specific heats differences between water and soil, the analyses were regulated using slopes to linearly describe their trends. For all analyses, the best model was achieved for a 10 s slope. Three different approaches were considered, two in the laboratory and one in the field. The first laboratory-based one was centred on active infrared thermography, considered measurement of temperature variation as independent variable and reported r = 0.74. The second laboratory–based one was focused on active infrared thermometry, added irradiation as independent variable and reported r = 0.76. The in-field experiment was performed by active infrared thermometry, heating bare soil by solar irradiance after exposure due to primary tillage. Some meteorological parameters were inserted as independent variables in the prediction model, which presented r = 0.61. In order to obtain more general and wide estimations in-field a Partial Least Squares Discriminant Analysis on three classes of percentage of soil water content was performed obtaining a high correct classification in the test (88.89%). The prediction error values were lower in the field with respect to laboratory analyses. Both techniques could be used in conjunction with a Geographic Information System for obtaining detailed information on soil heterogeneity

Comparison of microwaves and conventional thermal treatment on enzymes activity and antioxidant capacity of kiwifruit puree

Enzymes are naturally present in food and can cause product deterioration. For this reason,most food-processing steps try to reduce the enzymatic activity. The aimof thisworkwas to compare, in terms of both the inactivation of kiwifruit puree peroxidase, polyphenoloxidase and pectinmethylesterase and also themaintenance of the antioxidant capacity of the product, the effect of a microwave treatment with a conventional thermal treatment designed to cause the same level of peroxidase inactivation (90%). The microwave power and process time that best permitted the maximisation of both the enzyme inactivation and the antioxidant capacity of the product, were selected by means of the Response Surface Methodology. The results obtained point to microwave heating as an appropriate technology with which to produce a stable kiwifruit puree, since these treatments were more effective at enzyme inactivation and antioxidant capacity retention than the conventional thermal treatment.The authors thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Project AGL 2010-22176 and the Generalitat Valenciana for the financial support given throughout Project ACOMP/2012/161 and the Grant awarded to the author Maria Benlloch.Benlloch Tinoco, M.; Igual Ramo, M.; Rodrigo Aliaga, MD.; Martínez Navarrete, N. (2013). Comparison of microwaves and conventional thermal treatment on enzymes activity and antioxidant capacity of kiwifruit puree. Innovative Food Science and Emerging Technologies. 19:166-172. https://doi.org/10.1016/j.ifset.2013.05.007S1661721

Superiority of microwaves over conventional heating to preserve shelf-life and quality of kiwifruit puree

[EN] The effect of both microwave (1000 W-340 s) and conventional heating (97 degrees C-30 s) on the quality and shelf-life of kiwifruit puree was investigated. The growth of microorganisms and the evolution of enzyme activity, colour, pH, bioactive compounds and antioxidant activity in the product during storage at 4, 10 and 22 degrees C were checked. The storage temperature had a significant (p < 0.05) impact on both the shelf-life and the nutritional and functional value of the samples: the higher the temperature, the significantly (p <0.05) faster the rate of both the sample spoilage and the loss of the bioactive compounds. On the other hand, thermal processing significantly (p < 0.05) reduced the growth of microorganisms and the degradation rate of some bioactive compounds in a 12-59%, as well as leading to enzyme and colour stabilization. A longer shelf-life (123 days at 4 degrees C) and a superior preservation of colour (Delta E-SE = 6.54) and bioactive compounds (57-67%) were obtained when microwave heating was the technology selected to process the kiwifruit puree. Microwave heating was considered a suitable means of preserving kiwifruit puree that might be successfully employed as an innovation tool with which to help safe, high-quality and minimally processed kiwifruit based-products reach the market.The authors thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Projects AGL 2010-22176 and AGL 2010-22206-C02-01 and the Generalitat Valenciana for the Grant awarded to the author Maria Benlloch.Benlloch Tinoco, M.; Igual Ramo, M.; Rodrigo Aliaga, MD.; Martínez Navarrete, N. (2015). Superiority of microwaves over conventional heating to preserve shelf-life and quality of kiwifruit puree. Food Control. 50:620-629. https://doi.org/10.1016/j.foodcont.2014.10.006S6206295

Listeria Monocytogenes inactivation kinetics under microwave and conventional thermal processing in a kiwifruit puree

The inactivation of Listeria monocytogenes in a kiwifruit puree by conventional and microwave heating was studied. Survival curves at three microwave power levels (600 1000 W) and three temperatures (50 60 °C) were obtained. Data were properly fitted by a first-order kinetic model. Processing times under both technologies were corrected to isothermal treatment for the kinetic study. Microwave heating was shown to effectively inactivate L. monocytogenes. In the range of microwave and conventional processing conditions assayed, the 5-log10 reductions of L. monocytogenes recommended by the FDA for pasteurized products were achieved. The level of microwave power applied had a considerable influence on the Listeria monocytogenes inactivation rate. The higher the power level, the faster the inactivation. The inactivation of Listeria monocytogenes under microwave heating at 900 W (D60°C=17.35 s) and 1000 W (D60°C=17.04 s) happened faster than in a conventional thermal process (D60°C=37.45 s). Consequently, microwave heating showed greater effectiveness for Listeria monocytogenes inactivation than conventional heating.The authors thank the Ministerio de Educacion y Ciencia for the financial support given through Projects AGL 2010-22176 and AGL 2010-22206-C02-01 and the Generalitat Valenciana for the financial support given through Project ACOMP/2012/161 and the Grant awarded to the author Maria Benlloch.Benlloch Tinoco, M.; Pina Pérez, MC.; Martínez Navarrete, N.; Rodrigo Aliaga, MD. (2014). Listeria Monocytogenes inactivation kinetics under microwave and conventional thermal processing in a kiwifruit puree. Innovative Food Science and Emerging Technologies. 22:131-136. https://doi.org/10.1016/j.ifset.2014.01.005S1311362

Effects of Microwave Heating on Sensory Characteristics of Kiwifruit Puree

The effect of microwave processing on the characteristics of kiwifruit puree was evaluated by applying various gentle treatments. Different combinations of microwave power/processing time were applied, with power among 200-1,000 W and time among 60-340 s, and various sensory and instrumental measurements were performed with the aim of establishing correlations and determining which instrumental parameters were the most appropriate to control the quality of kiwi puree. The water and soluble solids of the product, 83 and 14/100 g sample, respectively, did not change due to treatments. For sensory assessment, an expert panel was previously trained to describe the product. Fourteen descriptors were defined, but only the descriptors 'typical kiwifruit colour', 'tone', 'lightness', 'visual consistency' and 'typical taste' were significant to distinguish between kiwifruit puree samples. The instrumental analysis of samples consisted in measuring consistency, viscosity, colour and physicochemical characteristics of the treated and fresh puree. Applying intense treatments (600 W-340 s, 900 W-300 s and 1,000 W-200 s) through high power or long treatment periods or a combination of these factors, mainly affects the consistency (flow distance decreased from 5. 9 to 3. 4 mm/g sample), viscosity (increased from 1. 6 to 2. 5 Pa/s), colour (maximun ¿E was 6 U) and taste of the product. As a result, samples were thicker and with an atypical flavour and kiwifruit colour due to increased clarity (L* increased from 38 to 43) and slight changes in the yellow-green hue (h* decreased from 95 to 94). For the instrumental determinations of colour and visual perception of consistency, the most suitable parameters for quality control are the colour coordinates L*, a*, h*, whiteness index and flow distance measured with a Bostwick consistometer. © 2011 Springer Science+Business Media, LLC.The authors thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Project AGL 2010-22176. The authors are indebted to the Generalitat Valenciana (Valencia, Spain) for the Grant awarded to the author Maria Benlloch. The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Benlloch Tinoco, M.; Varela Tomasco, PA.; Salvador Alcaraz, A.; Martínez Navarrete, N. (2012). Effects of Microwave Heating on Sensory Characteristics of Kiwifruit Puree. Food and Bioprocess Technology. 5(8):3021-3031. https://doi.org/10.1007/s11947-011-0652-1S3021303158Albert, A., Varela, P., Salvador, A., & Fiszman, S. M. (2009). 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Assessment of microwave energy for disinfestation of grain Written for presentation at the CSAE/SCGR 2005 Meeting

Abstract. Infestation of grain by insects is widely controlled by the use of insecticides. Use of contact insecticides results in chemical residues left in the food which may have adverse effects on humans. Also insects develop resistance to both contact insecticides and fumigants. Microwave disinfestation offers an alternate way to disinfest grain. Microwaves are electromagnetic waves with frequencies ranging from 300 MHz to 300 GHz. The use of microwaves for killing insects is based on the dielectric heating of insects present in grain, which is a relatively poor conductor of electricity. There is a possibility of selective heating of insects in grain because of a significant difference in dielectric constants between grain and insects. The major advantage of using microwave energy is that no chemical residues are left in the food and insects are unlikely to develop resistance to this treatment. Principle of microwave disinfestation, experimental results from previous studies and the advantages of using microwaves for disinfestation of grain are discussed