Microwave-vacuum drying of round bamboo: A study of the physical properties

Lv, Huangfei; Ma, Xinxin; Zhang, Bo; Chen, Xiufang; Liu, Xian-Miao; Fang, Carol; Fei, Benhua

doi:10.1016/j.conbuildmat.2019.03.221

Cited by 59 publications

(14 citation statements)

References 17 publications

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“…A similar phenomenon has been found in the drying of banana (Dai, Yang, et al, 2020), potato (Duarte‐Correa et al, 2020), and kiwifruit slices (Zhang et al, 2020). This phenomenon may be due to the fact that the moisture in the material would absorb more microwave energy as the microwave power density increased (Lv et al, 2019), thereby accelerating the moisture migration rate. The drying process of papaya slices under different microwave power densities was almost coincident and mainly regarded as falling‐rate drying periods with a similar initial drying rate of 52.7 g (g −1 · min −1 ) (Figure 3b).…”

Section: Resultsmentioning

confidence: 99%

“…There was no significant difference ( p > .05) existing in the different drying temperature conditions. This may be because when the microwave power density and vacuum degree were constant, the ability of microwaves to generate heat inside the material was limited within a certain range and the internal temperature cannot rise any further; therefore, setting different drying temperatures would have little effect on the total drying process (Lv et al, 2019; Zhang, Lv, et al, 2020). Meanwhile, the drying rate of papaya slices under different temperature conditions continued to decline with the decrease of moisture content (Figure 4b).…”

Section: Resultsmentioning

confidence: 99%

“…In order to record the shrinkage rate of papaya accurately during the drying process, at least three different positions were selected for repeated measurements to avoid uneven shrinkage and bending situations. The shrinkage rate was calculated according to Equation (4) (Lv et al, 2019; Zhang, Lv, et al, 2020):

S goodbreak= ()(, 1 goodbreak- \frac{δ_{h}}{{normalδ}_{normalα}}) goodbreak\times 100 %

where δ α is the average slice thickness of fresh papaya; δ h is the average thickness of dried papaya slices.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Drying characteristics and quality optimization of papaya crisp slices based on microwave vacuum drying

Dai

et al. 2022

Food Processing Preservation

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In order to improve the drying quality and obtain a crispy texture of papaya slices, microwave vacuum drying (MVD) was studied in this research. The effects of different slice thickness (3, 6, 9, 12 mm), microwave power density (6, 8, 10, 12 W/g), drying temperature (50, 55, 60, 65, 70°C), and vacuum degree in relative pressure (−75, −80, −85, −90 kPa) on the drying characteristics and comprehensive quality of papaya slice were discussed. The Box-Behnken central combination experiments were designed

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

S goodbreak= ()(, 1 goodbreak- \frac{δ_{h}}{{normalδ}_{normalα}}) goodbreak\times 100 %

where δ α is the average slice thickness of fresh papaya; δ h is the average thickness of dried papaya slices.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Drying characteristics and quality optimization of papaya crisp slices based on microwave vacuum drying

Dai

et al. 2022

Food Processing Preservation

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“…The structure-induced variability of water sorption is a major problem in bamboo drying, causing uneven drying rate, differential shrinkages and drying stresses. This will result in dimensional instability (fiber twisting, warping or cupping) during drying process 30 – 32 . On the other hand, water sorption rate is also directly related to the ability to treat bamboo, e.g., mold resistant treatment using borate solution, both in terms of the treatment time and uniformity 33 .…”

Section: Resultsmentioning

confidence: 99%

Water vapor sorption behavior of bamboo pertaining to its hierarchical structure

Chen

Fang

Wang

et al. 2021

Sci Rep

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Bamboo is an anisotropic, hierarchical, and hygroscopic material. Moisture transport in bamboo is one of the most fundamental properties affecting almost all other physical and mechanical properties of the material. This study investigated the water vapor sorption behaviors of bamboo at various structural levels: cell walls, cells (with pits) and bamboo blocks. The specimens with two sorption directions, longitudinal (L) and transverse (T), were measured by saturated salt solution method and dynamic vapor sorption. The parallel exponential kinetics model was used to analyze the sorption kinetics. The results showed that at the cell wall level, the sorption rate and equilibrium moisture content (EMC) of cell wall in the L specimens were larger than those in the T specimens. The differences were probably caused by the looser cell wall layers in the L specimens. At the cellular scale, pits in the cell wall resulted in an enhanced sorption rate and EMC of the T specimens compared with the L specimens where the pits in the parenchyma cells were only distributed in the lateral walls but not in end walls. At the macro scale, the sorption rate and moisture content of bamboo blocks were largely controlled by the vessel cells. As a hierarchically-structured plant, bamboo performs the biological function of moisture transport at all these scales. This work helps improve the understanding of water transport behavior in bamboo, which may lead to better bamboo drying and impregnation processes.

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“…One application is to use round bamboo culms in their original shape, such as to construct bridges, houses, and furniture. − The other application is to use broken bamboo culms, which need to be split, sliced, or crushed before reassembling, to make pipes and floors. − Both of these applications are related to a significant concept, the weak layers in bamboo. The heterogeneous structure of round bamboo culms resulted in nonuniform shrinkage of the material during drying, storing, and use, eventually causing cracking in the weak layers (Figure b). − However, these weak layers were exploited to easily split, slice, or crush bamboo culms into different sizes (Figure b). As the machining processes and applications of bamboo are highly relevant to weak layers, it is crucial to investigate the properties of these layers.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Visualization of Weak Layers in Bamboo at the Cellular and Subcellular Levels

Chen

Wei

Tang

et al. 2020

ACS Appl. Bio Mater.

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Weak layers in bamboo, which are prone to the generation of cracks or are the preferred routes for crack growth, govern the machining processes and applications of bamboo. Weak layers are avoided during storing but are utilized during splitting and slicing. Gaining an understanding of the weak layers is a priority that will allow for the determination of whether to avoid or utilize them. In this study, scanning electron microscopy was used to observe the weak layers at the cellular and subcellular levels. A nanoindentation instrument and a Raman microscope were used to quantitatively characterize the mechanical properties and chemical components of these weak layers. The results show that among the three types of bamboo cells, vessel cells were the most vulnerable to damage, while fiber cells were the least susceptible to damage. The weak layers at the subcellular level were compound middle lamella (CML), thin layers of cell walls, and pits. The average storage modulus values were as follows: 13.7 GPa for CML, 17.0 GPa for pits, 20.6 GPa for thin layers, and 25.3 GPa for thick layers. Compared with the thick layers, the maximum decrement of cellulose content was 51% in CML and 41% in thin layers. With the lowest cellulose content, CML was the likeliest subcellular structure in which cracks propagated. The hardness of the pits was lower than that of the adjacent non-pit areas. The mechanical properties of bamboo increased by targeted modification of the weak layers. This work demonstrates a comprehensive investigation into weak layers of bamboo and quantitatively visualizes their mechanical and chemical properties.

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Microwave-vacuum drying of round bamboo: A study of the physical properties

Cited by 59 publications

References 17 publications

Drying characteristics and quality optimization of papaya crisp slices based on microwave vacuum drying

Drying characteristics and quality optimization of papaya crisp slices based on microwave vacuum drying

Water vapor sorption behavior of bamboo pertaining to its hierarchical structure

Quantitative Visualization of Weak Layers in Bamboo at the Cellular and Subcellular Levels

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