Ethanol pre-treatment to ultrasound-assisted convective drying of apple

Advances in application of ultrasound in food processing: A review

“…Researchers have reported that application of ultrasound can lead to pore formation and develop higher internal stress [93] . Rojas et al [99] observed that the treatment of apple with ethanol and ultrasound for 10 min at 25˚C efficiently increased the rate of rehydration. Wang et al [100] treated kiwifruit with ultrasound for 0–30 min at 20 KHz and showed that the treatment enhanced the rehydration ratio and reduced the rehydration time attributed to the larger tunnels or spaces in tissues created by ultrasound.…”

Comparison between airborne ultrasound and contact ultrasound to intensify air drying of blackberry: Heat and mass transfer simulation, energy consumption and quality evaluation

“…However, special attention should be paid that sonication cannot always protect food phenolic compounds under the exposure to hot air, or even intensify the destructive effect. Rojas et al [56] found no significant difference in phenolic content between dehydrated apple slices with and without airborne sonication. The results of Santacatalina et al [57] revealed that ultrasound application speeded up the degradation of phenolics during air drying of apple, probably due to ultrasonic assistance to the release of oxidative enzymes.…”

Combining ethanol pre‐treatment and ultrasound‐assisted drying to enhance apple chips by fortification with black carrot anthocyanin

“…The drying time reductions in E30% experiments were similar to those obtained in other products such as Guaco leaves, 16 garlic, 23 apple 17 or potato, 12 pre‐treated with greater ethanol concentration solutions (> 90% v/v ) and shorter times (from 5 s to 3 min). Nonetheless, time reductions above 50% were found during conventional drying of pumpkin 11,21 and apple samples, 19 all pre‐treated for longer times (from 15 to 60 min) by immersion in concentrated ethanol solutions (> 90% v/v ).…”

“…Thus, compared with Control experiments, ethanol pre‐treatment at highest solution concentration followed by ultrasonically assisted drying (E30%US) increased up to 134% the h value. It suggests that the ethanol pre‐treatment effects (related to ethanol properties, structure and composition modifications), which occurs especially in the sample surface 11–13,19,22,23 leads to modifications in the air‐product interface. These modifications could promote the water vaporization when ultrasound was applied.…”

“…The influence of ethanol has been studied individually as pre‐treatment to convective drying, 11,16–18 ultrasound‐convective drying 19 and vacuum drying, 20 or combined with ultrasound 21 to convective drying. In addition, in the case of infrared drying, ethanol pre‐treatments have been studied combined with vacuum 22 or with ultrasound 12,23 .…”