Using infrared thermography to evaluate the injuries of cold-stored guava

Abstract

This study aimed to identify using the infrared (IR) thermography data the injuries of guavas during cooling and storage at different temperatures. Three experiments were performed at three different temperatures with one storage time. The first experiment was done with static air in a refrigerator at 5°C, the second experiment was conducted in a tunnel with forced air at 10°C, and the third experiment was conducted in an air conditioned environment at 20°C. Mechanical injuries caused by the impact of a pendulum were induced on guava surfaces. The surface temperatures were obtained for bruised and sound tissues during cooling and storage using an Infrared (IR) camera. With thermography, it was possible to distinguish the injured tissues of the fruits that were unaffected at temperatures of 5, 10 and 20°C in first hours of cooling. The results suggest that the storage of guava fruits at 5°C in static air resulted in cold-induced injury, while storage at 20°C resulted in an altered activity pattern. The stored guava fruits were analyzed for mass loss, firmness, color, total sugars, total pectin and solubility. The parameters values were lower during the forced-air cooling and storage at 5 and 10°C. When stored at 20°C, there was fruit maturation that caused tissue softening, which makes the fruits more susceptible to deterioration and thermographic readings showed opposite trends.

Convective drying of food materials: An overview with fundamental aspect, recent developments, and summary

“…Air velocity didn't influence the images of slices compared with air temperature. Similar reports are given by Defraeye et al 45 while drying of apple slices and Gonçalves et al 47 during drying of guava slices.…”

“…From the images, higher and lower moisture content regions were identified and from that mass loss was estimated. More studies of thermal imaging during drying were noticed in Osroosh et al, 46 Gonçalves et al, 47 and Seyedabadi et al 48 …”

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

“…In order to evaluate the effect of HAD and MW, it is necessary to analyze thermal conditions on the surface of the product. Infrared thermography (FTIR) is a technique that measures the surface temperature of materials in a non-destructive way [13][14][15]. This technique has been used in the food industry to evaluate pork quality [16], to detect differences between raw and cooked chicken meat [17,18], to evaluate the freezing process of potato [4], to control disinfection with the steam of carrots [19], to detect the position and depth of bruises in apples [20] and to evaluate injuries of cold-stored guava [14].…”

“…Infrared thermography (FTIR) is a technique that measures the surface temperature of materials in a non-destructive way [13][14][15]. This technique has been used in the food industry to evaluate pork quality [16], to detect differences between raw and cooked chicken meat [17,18], to evaluate the freezing process of potato [4], to control disinfection with the steam of carrots [19], to detect the position and depth of bruises in apples [20] and to evaluate injuries of cold-stored guava [14]. Thermal imaging has also been demonstrated to be a useful tool in monitoring the surface temperature in drying processes in the food industry in combined dryings of kiwifruits [21], HAD combined with microwaves to dry mushrooms [22], HAD of corn kernels [23] and vacuum drying of banana slices [24].…”

Mechanism of firmness loss in guava cv. Pedro Sato during ripening at room temperature

“…Exports are destined for the European market without any post-harvest treatment (Vieira et al, 2014). However, the transport and storage period of guava (Psidium guajava L.) is limited by the very short shelf life after harvest and by highly perishability, which is associated with the loss of firmness in the pulp (Gonçalves et al, 2016).…”