This work aims at investigating structural changes occurring in vacuum drying (VD) compared with conventional convective drying of bananas, pineapples, and apples, and to find the appropriate thin‐layer equation for predicting the drying kinetic of products. Drying experiments were carried out at the drying air temperatures of 100 °C, 110 °C, and 120 °C at 4 kPa. The experimental results showed that the VD method at high temperature for all three types of fruits showed the fastest drying time, lowest degree of lightness, lower shrinkage, more pores, more crispness, and more rehydration ability compared with conventional drying and low‐temperature drying. Consequently, the VD at drying air temperature of 120 °C was suggested as the best drying condition. Moreover, six mathematical models describing thin‐layer drying were investigated. The Logarithmic equation was considered adequate for describing the thin‐layer drying behavior of apples, while the Diffusion approach equation was deemed adequate for bananas and pineapples. Practical applications Dried agricultural products serve as important healthful snack items around the world. Vacuum drying (VD) is another process in which products are dried in a reduced pressure environment. The products obtained by the process were of exceptionally high quality. Moreover, none have investigated the effect of VD on structural changes (in terms of shrinkage, rehydration behavior, microstructure, texture, and color) of bananas, pineapples, and apples at drying air temperatures of 100 °C, 110 °C, and 120 °C and absolute pressure of 4 kPa. The result from this research can be applied to the development of dried agricultural product in Thailand.
The objective of this research was to study the optimum condition for the vacuum drying of banana slices using a vacuum dryer and to find out the appropriate thin layer equation for predicting the drying kinetic of bananas. The experiments were carried out at the drying temperatures of 60, 70, 80 and 90oC and absolute chamber pressure of 30 mmHg. The drying experiments were performed until the samples moisture content was lower than 3.4% (w.b.). Next, the dried products were analyzed for physical quality (in terms of color, shrinkage, and texture) and sensory quality (in terms of color, texture, flavor, crispness and overall acceptability). These data were used in choosing the optimum condition for the vacuum drying of banana slices. From experimental results, the drying time at the highest drying temperature was the shortest. At this condition, the dried banana slices showed the highest degree of yellowness, lower shrinkage, and more crispness compared to lower drying temperatures. From sensory analysis, each drying condition showed significant effect on consumer acceptability with the drying temperature of 70, 80 and 90oC showing the levels of the overall acceptability sensory qualities of dried banana is not significantly different. Consequently, the drying temperature of 90oC was suggested as the best drying condition for sliced bananas. Moreover, three mathematical models (Newton, Logarithmic and Page) describing thin layer drying were investigated. It was found that the thin layer equation providing the highest coefficient of determination (R2) and the lowest chi-square (X2) and root mean square error (RMSE) was the Logarithmic equation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.