Air pollution and livestock production

The air in a livestock farming environment contains high concentrations of dust particles and gaseous pollutants. The total inhalable dust can enter the nose and mouth during normal breathing and the thoracic dust can reach into the lungs. However, it is the respirable dust particles that can penetrate further into the gas-exchange region, making it the most hazardous dust component. Prolonged exposure to high concentrations of dust particles can lead to respiratory health issues for both livestock and farming staff. Ammonia, an example of a gaseous pollutant, is derived from the decomposition of nitrous compounds. Increased exposure to ammonia may also have an effect on the health of humans and livestock. There are a number of technologies available to ensure exposure to these pollutants is minimised. Through proactive means, (the optimal design and management of livestock buildings) air quality can be improved to reduce the likelihood of risks associated with sub-optimal air quality. Once air problems have taken hold, other reduction methods need to be applied utilising a more reactive approach. A key requirement for the control of concentration and exposure of airborne pollutants to an acceptable level is to be able to conduct real-time measurements of these pollutants. This paper provides a review of airborne pollution including methods to both measure and control the concentration of pollutants in livestock buildings

Hot Air and Microwave Combined Drying of Potato Monitored by Infrared Thermography

[EN] Hot air drying (HAD) at temperatures below the spontaneous evaporation temperature could be combined with microwave (MW) radiation as a thermal energy source in order to reduce the drying time. A photon flux in the microwave range interacts with dipolar molecules (water) through orientation and induction, producing electrical energy storage and thermal energy accumulation and generating an increase in the internal energy of food. The different mechanisms involved in water transport could change when the microwave penetration depth exceeds the sample characteristic dimension of mass transport. The aim of this paper is to determine the effect of MW in the combined HAD-MW drying of raw potato in order to obtain the real driving forces and mechanisms involved in the water transport, with the purpose of optimizing the MW power used. For this purpose, combined drying was carried out on potato samples (0, 4 and 6 W/g). The sample surface temperature was monitored by infrared thermography, and the sample mass was measured continuously through a precision balance. In parallel with continuous drying, another drying treatment was performed at different times (20, 40, 60, 90, 120, 180, 420 min) and conditions (0, 4 and 6 W/g) to analyze the dielectric properties, mass, moisture, volume and water activity. The results show that it is possible to monitor combined drying by infrared thermography, and it can be concluded that the convection heating is mostly transformed into surface water evaporation, with negligible thermal conduction from the surface, and microwave radiation is mostly transformed into an increase in the potato's internal energy.The authors acknowledge the financial support from THE SPANISH MINISTERIO DE ECONOMÍA, INDUSTRIA Y COMPETITIVIDAD, Programa Estatal de I+D+i orientada a los Retos de la Sociedad AGL2016-80643-R, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER). Juan Ángel Tomás-Egea wants to thank the FPI Predoctoral Program of the Universitat Politècnica de València for its support.Tomas-Egea, JA.; Traffano-Schiffo, MV.; Castro Giraldez, M.; Fito Suñer, PJ. (2021). Hot Air and Microwave Combined Drying of Potato Monitored by Infrared Thermography. Applied Sciences. 11(4):1-12. https://doi.org/10.3390/app11041730S112114Traffano-Schiffo, M. V., Castro-Giráldez, M., Fito, P. J., & Balaguer, N. (2014). Thermodynamic model of meat drying by infrarred thermography. Journal of Food Engineering, 128, 103-110. doi:10.1016/j.jfoodeng.2013.12.024Dehghannya, J., Kadkhodaei, S., Heshmati, M. K., & Ghanbarzadeh, B. (2019). Ultrasound-assisted intensification of a hybrid intermittent microwave - hot air drying process of potato: Quality aspects and energy consumption. Ultrasonics, 96, 104-122. doi:10.1016/j.ultras.2019.02.005Turkan, B., Canbolat, A. S., & Etemoglu, A. B. (2019). Numerical Investigation of Multiphase Transport Model for Hot-Air Drying of Food. Tarım Bilimleri Dergisi, 518-529. doi:10.15832/ankutbd.441925Cuibus, L., Castro-Giráldez, M., Fito, P. J., & Fabbri, A. (2014). Application of infrared thermography and dielectric spectroscopy for controlling freezing process of raw potato. Innovative Food Science & Emerging Technologies, 24, 80-87. doi:10.1016/j.ifset.2013.11.007Castro-Giráldez, M., Fito, P. J., & Fito, P. (2011). Nonlinear thermodynamic approach to analyze long time osmotic dehydration of parenchymatic apple tissue. Journal of Food Engineering, 102(1), 34-42. doi:10.1016/j.jfoodeng.2010.07.032Talens, C., Castro-Giraldez, M., & Fito, P. J. (2016). A thermodynamic model for hot air microwave drying of orange peel. Journal of Food Engineering, 175, 33-42. doi:10.1016/j.jfoodeng.2015.12.001Markx, G. H., & Davey, C. L. (1999). The dielectric properties of biological cells at radiofrequencies: applications in biotechnology. Enzyme and Microbial Technology, 25(3-5), 161-171. doi:10.1016/s0141-0229(99)00008-3Miraei Ashtiani, S.-H., Sturm, B., & Nasirahmadi, A. (2017). Effects of hot-air and hybrid hot air-microwave drying on drying kinetics and textural quality of nectarine slices. Heat and Mass Transfer, 54(4), 915-927. doi:10.1007/s00231-017-2187-0Dehghannya, J., Bozorghi, S., & Heshmati, M. K. (2017). Low temperature hot air drying of potato cubes subjected to osmotic dehydration and intermittent microwave: drying kinetics, energy consumption and product quality indexes. Heat and Mass Transfer, 54(4), 929-954. doi:10.1007/s00231-017-2202-5Swain, S., Samuel, D. V. K., Bal, L. M., Kar, A., & Sahoo, G. P. (2012). Modeling of microwave assisted drying of osmotically pretreated red sweet pepper (Capsicum annum L.). Food Science and Biotechnology, 21(4), 969-978. doi:10.1007/s10068-012-0127-9Talens, C., Castro-Giraldez, M., & Fito, P. J. (2017). Effect of Microwave Power Coupled with Hot Air Drying on Sorption Isotherms and Microstructure of Orange Peel. Food and Bioprocess Technology, 11(4), 723-734. doi:10.1007/s11947-017-2041-xWang, Q., Li, S., Han, X., Ni, Y., Zhao, D., & Hao, J. (2019). Quality evaluation and drying kinetics of shitake mushrooms dried by hot air, infrared and intermittent microwave–assisted drying methods. LWT, 107, 236-242. doi:10.1016/j.lwt.2019.03.020Glowacz, A. (2021). Fault diagnosis of electric impact drills using thermal imaging. Measurement, 171, 108815. doi:10.1016/j.measurement.2020.108815Gonçalves, B. J., Giarola, T. M. de O., Pereira, D. F., Vilas Boas, E. V. de B., & de Resende, J. V. (2015). Using infrared thermography to evaluate the injuries of cold-stored guava. Journal of Food Science and Technology, 53(2), 1063-1070. doi:10.1007/s13197-015-2141-4Gowen, A. A., Tiwari, B. K., Cullen, P. J., McDonnell, K., & O’Donnell, C. P. (2010). Applications of thermal imaging in food quality and safety assessment. Trends in Food Science & Technology, 21(4), 190-200. doi:10.1016/j.tifs.2009.12.002Costa, N., Stelletta, C., Cannizzo, C., Gianesella, M., Lo Fiego, P., & Morgante, M. (2007). The use of thermography on the slaughter-line for the assessment of pork and raw ham quality. Italian Journal of Animal Science, 6(sup1), 704-706. doi:10.4081/ijas.2007.1s.704Tao, Y. (2000). Combined IR imaging-neural network method for the estimation of internal temperature in cooked chicken meat. Optical Engineering, 39(11), 3032. doi:10.1117/1.1314595J. G. Ibarra, Y. Tao, A. J. Cardarelli, & J. Shultz. (2000). COOKED AND RAW CHICKEN MEAT: EMISSIVITY IN THE MID-INFRARED REGION. Applied Engineering in Agriculture, 16(2), 143-148. doi:10.13031/2013.5060Gan-Mor, S., Regev, R., Levi, A., & Eshel, D. (2011). Adapted thermal imaging for the development of postharvest precision steam-disinfection technology for carrots. Postharvest Biology and Technology, 59(3), 265-271. doi:10.1016/j.postharvbio.2010.10.003Baranowski, P., Mazurek, W., Wozniak, J., & Majewska, U. (2012). Detection of early bruises in apples using hyperspectral data and thermal imaging. Journal of Food Engineering, 110(3), 345-355. doi:10.1016/j.jfoodeng.2011.12.038Zhou, X., Ramaswamy, H., Qu, Y., Xu, R., & Wang, S. (2019). Combined radio frequency-vacuum and hot air drying of kiwifruits: Effect on drying uniformity, energy efficiency and product quality. Innovative Food Science & Emerging Technologies, 56, 102182. doi:10.1016/j.ifset.2019.102182Su, D., Lv, W., Wang, Y., Li, D., & Wang, L. (2019). Drying characteristics and water dynamics during microwave hot-air flow rolling drying of Pleurotus eryngii. Drying Technology, 38(11), 1493-1504. doi:10.1080/07373937.2019.1648291Wei, S., Wang, Z., Wang, F., Xie, W., Chen, P., & Yang, D. (2019). Simulation and experimental studies of heat and mass transfer in corn kernel during hot air drying. Food and Bioproducts Processing, 117, 360-372. doi:10.1016/j.fbp.2019.08.006Pu, Y.-Y., Zhao, M., O’Donnell, C., & Sun, D.-W. (2018). Nondestructive quality evaluation of banana slices during microwave vacuum drying using spectral and imaging techniques. Drying Technology, 36(13), 1542-1553. doi:10.1080/07373937.2017.141592

The drying of foods using supercritical carbon dioxide

Food drying techniques such as air and freeze drying are not ideal: high temperatures used during air drying result in degradation of nutrients and sensorial properties, while freeze drying is expensive and therefore only applicable to high value foods. As an alternative to such drying techniques, drying with supercritical carbon dioxide was investigated here. Initially, carrot was dried using this technique. Addition of a co-solvent (ethanol) to the supercritical fluid was used as a method to increase the water solubility in the supercritical fluid and therefore aid drying. Analysis of the dried and rehydrated product structure, rehydration properties and mechanical properties was carried out which gave an indication of product quality. Drying of agar, containing varying concentrations of sugar was carried out on a laboratory and pilot plant scale. Gel structure and gel properties were studied. Addition of sugar to agar gel pieces improved structural retention considerably during drying. Fourier transform infrared analysis was used to investigate interactions that may be responsible for structural differences seen during supercritical drying. Changes in experimental parameters such as flow rate and depressurisation rate did not appear to have a significant effect on the dried gel structure. The supercritical drying technique investigated allowed food products to be dried and unique structures to be created with different rehydration and textural properties to the equivalent food products dried by air or freeze drying