Use of Ultrasound for Dehydration of Papayas

Abstract

This work evaluated the production of dehydrated papayas (Carica papaya L.) with low sugar content. The product was obtained applying ultrasonic waves to enhance the loss of sugar from the fruit. To achieve this goal, this paper examined the influence of the ultrasonic pre-treatment before air-drying on dehydration of papaya. Ultrasonic pre-treatment for air-drying of fruits was studied and compared with osmotic dehydration. This study allowed estimate of the effective diffusivity water in the air-drying process for papayas submitted to ultrasonic pretreatment. Results show that the water effective diffusivity increases after application of ultrasound causing a reduction of about 16% in the drying time. During ultrasonic treatment the papayas lost sugar (13.8% in 30 min), so such a pre-treatment stage can be a practical process to produce dried fruits with lower sugar content.

Effects of Ultrasound on Polyphenol Retention in Apples After the Application of Predrying Treatments in Liquid Medium

“…Surprisingly, no statistically significant sonication effects on soluble solids leakage were noticed (Fig. 1), which contrasts with the result obtained by Fernandes et al (2008c), where the ultrasound effect in enhancing the removal of soluble solids from papaya fruit to the distilled water was clearly established.…”

“…For example, when subjecting pineapple slices to 30 min in distilled water, Fernandes et al (2009) reported a loss of 23.2 % of fruit sugars, in which, although less than we obtained, the difference can be attributed to factors such as much longer trials and the more open and spongy structure of apple tissue. The same research team described the relation between treatment time and sugar transfer, where a prolonged time of immersion of papaya pieces in distilled water led to a higher solid decline (Fernandes et al 2008c). In the case of apple cubes soaked in distilled water, the treatment time extension from 45 to 90 min increased the solid losses from 48.0 to over 60 %.…”

Ultrasound assisted osmotic dehydration of organic cranberries (Vaccinium oxycoccus): Study on quality parameters evolution during storage

“…The result is a partial dewatering impregnation, which allows an increase of the shelf-life of OD material (Goula, Kokolaki, & Daftsiou, 2017;Kaymak-Ertekin, F. & Sultanolu, 2000; Sled z, Radoj cin et al, 2015; Rzą ca, Witrowa-Rajchert, Tylewicz, & Rosa, 2009;Tylewicz et al, 2011). However, this process is long and often requires the acceleration of mass transfer using traditional methods as agitation and rotation or new techniques as for example ultrasound (Deng & Zhao, 2008;Fernandes, Oliveira, & Rodrigues, 2008;Goula et al, 2017;Nowacka, Tylewicz, Laghi, Dalla Rosa, & Witrowa-Rajchert, 2014). Ultrasound (US) is an air vibration in the frequency from 20 kHz to 100 MHz.…”

Osmotic dehydration of Braeburn variety apples in the production of sustainable food products

“…A positive effect of the concentrate addition was obtained at a temperature of 60°C (inducing a decrease in U red of 5%), while at lower temperatures, this factor was detrimental (values increased by 2-4%). Fernandes et al (2008) also show that ultrasound application increases diffusivity during the osmotic dehydration of papayas. Osmotic pre-treatment before convective drying significantly increased water activity (WA) (0.260) as compared to the control samples dried without pre-treatment (0.246) (Fig.…”

“…Moreover, it enhances the penetration of the osmotic solution (Rastogi et al, 2000). Osmotic dehydration, combined with the use of ultrasound, intensifies mass exchange and reduces the pre-treatment and drying times (Fernandes et al, 2008;Ciurzyńska et al, 2014). Oliveira et al (2011) researched osmotic dehydration of apples in a sucrose solution combined with ultrasound before drying and showed that the drying time was shortened.…”