Abstract This work aimed to show heterogeneities in shelf life of table grapes from a same batch during road refrigerated transportation. The monitoring of temperature and relative humidity of air was done with a wireless sensor network strategically distributed among grapes boxes and pallets. The ambient conditions and time of exposure were associated with a linear predictive model of water loss in order to estimate fruits shelf life. Results showed that the loss of dynamic life of grapes varied according to the box position on different pallets within the refrigerated transport vehicle, due to differences in the conditions that fruits were exposed to. It was observed high heterogeneity in shelf life of the evaluated batch of grapes during transportation, with differences of 71 days between grape boxes. With that, one can conclude that these differences must be taken into account in the following stages of grapes cold chain.

Abstract This study aimed to evaluate the effect of the variability in ambient air conditions (temperature and relative humidity) and periods of exposure on the same batch of table grapes in the first stages of the fruit supply chain (harvesting, processing and storage prior to commercialization), in order to predict their dynamic shelf life. To estimate the shelf life we used a linear prediction model dependent on time and ambient air conditions (temperature and relative humidity). It was noted that during processing, there was considerable variations in ambient air conditions that grapes were exposed to, especially in harvesting stage. The ambient of following stages showed homogeneity in air conditions, but the residence time and the way of palletizing grapes affected their shelf life. We observed heterogeneity in the shelf life among different grape pallets and among boxes on a same pallet, with variations of up to 34 days. Thus, we ascertained a heterogeneity in the quality of table grapes from the same production batch, due to the variability in ambient air conditions and period of exposure, which should be considered in the logistics management of the dynamic shelf life of the product in the cold chain.

Abstract In this work, an experimental unit of a vacuum spray dryer was built. This prototype attempted to combine the advantages of freeze-drying (drying at low temperatures due to vacuum) and spray drying (increase of surface area aiming the improvement of heat transfer efficiency). Maltodextrin solutions were dried in the vacuum operated equipment and in conventional spray dryer. The vacuum spray dryer system allowed obtaining powder at low temperatures due to the lowering of pressure conditions (2-5 kPa) inside the drying chamber. The products obtained in the two systems were characterized and compared for particle size distribution, moisture content, water activity, bulk density and solubility in water. The processes yields were also evaluated and compared. The vacuum spray dryer system allowed the production of larger, more soluble and less dense particles than those obtained in the conventional configuration of the equipment, resulting in drier and, therefore, with lower water activity particles. Thus, the use of the vacuum spray dryer as a drying technique may be an alternative for the production of powder rich in thermosensitive compounds.

The search for efficient and accessible cooling systems has increased worldwide. This study aims to build and evaluate an evaporative cooling system using a water driven ejector, allowing it to be installed in places with plenty of water. The system was investigated varying the flow rate and temperature of the circulating water, temperature of the replacement water, and coefficient of performance. The best vacuum obtained was 8.5 kPa at nominal operating conditions of 4.1 ± 0.1 m³/h and 5 ± 0.5 ºC for the circulating water reaching the temperature of 9.7 ± 0.5 ºC. The pulse-like disturbance generated by replacing the cooling water at different periods of times did not result in significant affect vacuum destabilization and the temperature rise in the cooling tank. The coefficient of performance of the system at the highest thermal power of 92.27 W was 0.077, which was underestimated due to possible problems related to pump efficiency. The system evaluated under the conditions proposed can be very efficient for cooling fluids at higher temperatures, and it can be complementary to main refrigeration systems.