This work aims to estimate the shelf life of Golden Delicious apple fruit stored at room temperature by determining the changing trend in color every week using a non-destructive measurement method. Moreover, the study will measure the changes in weight loss (Δm) and the total soluble solids (TSS) contained in the apple. The research focuses on the last stage of ripening and the effect of shelf life affecting consumer behavior; therefore, the examined fruits were picked at the end of the season and were stored at an ambient temperature and in controlled laboratory conditions for six weeks, at 24 °C under 60% RH relative. Color measurements were performed with a portable color sensor, which provided a simple and effective examination method in the case of an appropriate number of fruit samples. The findings showed a significant increase in TSS and weight loss over time. Color varying (ΔE) and chroma (C*) parameters increased with prolonged storage duration, meaning that the color of the apples became darker and more color-saturated at the end of storage. While weight loss and TSS follow a linear tendency in the given storage period, the color changes in deteriorating fruits were characterized by exponential asymptotic regression. It was found that although the moisture content reaches its limit value during the drying process of apples, the saturation of color coordinates allows for determination of the limit parameters of consumption in the linear stage of weight loss. The saturation limits (70.97; 12.77; 56.34 CIELAB L*; a*; b*), the dominant color part (b*), and the growth rate of the saturation curves allow an accurate characterization of ripening from the visual aspect, thus determining the limit parameters of shelf life and improving the critical analysis factors affecting the life of fruits after harvest. By assessing color characteristics using a non-destructive technology, customers may quickly evaluate the quality of apples and make better decisions during their purchase.

The measurement of electrical conductivity (EC) has long been a tool for understanding soil properties. Previous studies concluded that EC measurement is not an ion-selective method, but these papers did not address the measurement frequency. An experimental tool and method were developed for semi-factory conditions in a large-scale soil trough at the Institute of Technology of the Hungarian University of Agricultural and Life Sciences. A specially designed and built test apparatus mounted on the tractor’s three-point hitch was used as a measuring device. The wear-resistant steel elements of the measuring device were also the sensors for measuring EC. This paper describes the conditions of the measurement series, the measurement results, and our conclusions from the experiments with the soil sensor. Different characteristics were measured in soil moistened with K and Ca solutions at different concentrations. The EC values show an increasing tendency with increasing salt concentration, and we also found that the rate of change of EC is different for different solution ratios. Based on our measurements, we found that the best method to isolate concentration differences is to use the test frequency range 20 Hz–250 kHz.

This research aims to determine whether the treatment of food products in a microwave electromagnetic field is advantageous or disadvantageous compared to conventional technologies. In household practice, microwave energy transfer is used mostly for heating. One of the most important tangible benefits of microwave heat treatment is that it causes less damage to the nutritional value of the product due to its speed.Despite the fact that microwave technology was introduced more than 70 years ago, it is still not clear whether its application results in equivalent products in terms of quality and food safety.This study demonstrates how heat-treated wines with microwave energy transmission and with convective heating in a thermostatic water bath are affected. In the white, rose and red wine samples pasteurized at a temperature of 74 ± 0.5 °C, significant differences between the two heating methods regarding colour characteristics could be indicated.

This study analyzed the impact of storing Golden Delicious apples at 3 °C with a relative humidity of 85 ± 5% in two environments, namely a darkroom (D03) and a lightroom (L03), on the fruit quality. The research evaluated weight loss (Δm) and color metrics (a*, b*, L*, ΔE, C*, hue angle). The number of apples used for each storage was 12. Weight loss was calculated by measuring the changes in mass during storage. Color differences (ΔE), chroma (C*), and hue angle were determined based on the L*a*b* scale values. Apples stored at 3 °C in D03 experienced a minimal percentage of weight loss of 7.02%. The results indicated that compared to the D03 storage, the L03 storage had a more significant increase in Δm and color variation. The non-destructive method of measuring color characteristics facilitates the assessment of the storage conditions for Golden Delicious apples.

The boiler is an enclosed vessel that transfers the energy from fuel combustion or electricity into hot water or steam. Then, this hot water or pressurized steam is used for transferring the heat to a certain heat process. Usually, the required hot water or steam keeps on varying throughout the day which also may be implied on the daily or monthly load. Therefore, several configurations of connecting the boiler into the solar heating system ensure the temperature of the final output. The boiler can be connected in series or parallel to improve the efficiency of the overall process as well as to reduce the running costs. This paper presents a simulation study of a solar heating system for industrial processes. Two flow-heater system configurations are designed for covering the heat demand of a pasteurising factory existing in Budapest, Hungary. The configuration “A” consists of a solar heating system for hot water preparation using in series flow heater configuration. While configuration “B” consists of the same solar system but with a parallel flow heater configuration. These system configurations are modelled using T*sol software for evaluating the system performance under the Hungarian climate from five different aspects: required collector area, glycol ratio, volume flow rate, relative tank capacity, and tank height-to-diameter ratio. According to the optimum design parameters, in series configuration is better than parallel by 3.14% at 45 m² collector area, 0.45% at 25% glycol ratio, 0.42% at 50 l/h · m² volume flow rate, 2.05% at 50 l/m² relative tank capacity, and 0.42% at 1.8 tank height-to-diameter ratio respectively. The results show that in series configuration is better in terms of solar fractions than parallel configuration from all five aspects.