Characterisation of osmotically dehydrated papaya with further hot air drying and microwave vacuum drying

Abstract

Summary Papaya was subjected to osmotic dehydration (OD) prior to hot air drying (HA; 70 °C) and microwave vacuum drying (MVD; 3.75 W g−1 and 13.3 kPa). An increase in immersion time in a sucrose solution [65/100 g (w/w)] at 40 ± 2 °C from 0 to 4 h decreased moisture content from 7.5802 to 1.2215 kg water kg dry solid−1. During HA and MVD, effective moisture diffusivity was in the range 7.09 × 10−8 to 9.13 × 10−8 m2 s−1 and 2.85 × 10−6 to 3.50 × 10−6 m2 s−1, respectively, depending on immersion time. The hue angle of HA samples was 0.83–0.91, whereas that of MVD samples was 48.55–50.32. Both drying methods decreased springiness. Porosity was clearly observed in MVD samples. Rehydration rate was enhanced by increased immersion time and MVD (P ≤ 0.05). From preference mapping, MVD samples were more preferable than HA samples. Moreover, MVD samples with 1–3 h OD were more preferable than those with 4 h OD.

Influence of Pretreatments on Microwave Vacuum Drying Kinetics, Physicochemical Properties and Sensory Quality of Apple Slices

“…The ratio of material to liquid was 1:8 (w/v) and a stirring was done with a glass rod every 30 min. After the osmotic dehydration was fi nished, the samples were taken out and the surface sucrose solution was removed using a fi lter paper prior to drying [Nimmanpipug et al, 2013].…”

“…The most remarkable change in color was observed in the dried product submitted to OD and UT, indicating that the severe browning occurred in both of them. The browning in fruits may commonly attribute to the oxidation of phenolics and to caramelization [Rodríguez et al, 2015;Nimmanpipug et al, 2013]. Various methods including lowering pH, applying citric acid as a metal chelator, and avoiding exposure to oxygen have been studied for inhibiting PPO or slowing the browning reaction, and the sulfur dioxide treatment is still the most effective method and has been widely used in the food industry [Krokida et al, 2000;Igual et al, 2012].…”

“…They are a part [Zhang et al, 2006]. Numerous studies have confi rmed that MVD yields high-quality dehydrated products that are similar to or better than those dried by FD [Nimmanpipug et al, 2013;Chong et al, 2013]. Besides, MVD possesses advantages including shortened drying time, improved energy effi ciencies, and reduced energy consumption [Zhang et al, 2006].…”

Drying Characteristics of Agricultural Products under Different Drying Methods: A Review

“…MW combination drying was better than HA drying alone in terms of color values. The effectiveness of MW and VC drying on the osmotic dehydration of papaya was evaluated by Nimmanpipug and Therdthai (2013). The hardness of papaya samples dried by MW and VC was lower than that of the samples dried by HA alone.…”

Cambios en la Textura y Color en Mango (Tommy Atkins) PreSecado por Deshidratación Osmótica y Microondas

“…El efecto del proceso de deshidratación en la superficie del mango se ve reflejado por los cambios y pérdida de color (Gómez, 2013;Chacón y Esquivel, 2013) por oxidación extensiva provocando una pérdida en carotenoides que es incrementada por la prolongación de la deshidratación (Zuluaga et al, 2010). La deshidratación puede incrementar la concentración de carotenoides (Nimmanpipug y Therdthai, 2013;Phisut et al, 2013) causando un efecto contrario en el color del producto final.…”