Study on the Rehydration Quality Improvement of shiitake Mushroom by Combined Drying Methods

Abstract

The aim of study is to improve the rehydration quality of dried shiitake mushrooms for their instant food manufacturers and fast restaurants. Serial combined drying methods were investigated to achieve this objective: either instant controlled pressure drop drying (DIC) or freeze drying (FD) was used as the treatments for microstructure improvement, and they were applied either before or after an additional drying step at low (35 °C) or high (65 °C) temperatures. Dried mushrooms were assessed for quality indicators like relative volume, rehydration rate, dry matter loss and sensory scores. Microstructure properties were inferred to understand the physical mechanisms of quality changes. Principal component analysis (PCA) was used to cluster treatments and to identify combinations of drying techniques, rendering improved quality. Consequently, it was shown that DIC treatment before hot air drying at 35 °C was shown to be the most promising combined drying method to enhance the rehydration quality, leading to a high volume recovery ratio, low dry matter loss after rehydration, and high rehydration rates. This good performance could be explained by the retention of pore interconnectivity resulting from the slight expansion of porous structure during DIC and the retention of cell membrane integrity.

Postharvest of fresh white shimeji mushroom subjected to UV-C radiation

“…Samples were frozen for later bioactive analyses. For total antioxidant activity and total extractable polyphenols, samples were dried in circulation and air renewal oven (Tecnal, TE-394/2-MP, Piracicaba, Brazil) at 65 °C for 4 h [ 29 ], and stored in a silica desiccator, in dark packaging, until the time of analysis.…”

Staged Temperature- and Humidity-Controlled Combined Infrared Hot-Air Drying (TH-IRHAD) of Sea Buckthorn Reduces Drying Time, Energy Consumption, and Browning

“…(6) Impact of the drying temperature on the rehydration ratio An essential metric for assessing dried products is the rehydration ratio, which can be used to describe the material destruction during the drying process [32]. A higher rehydration ratio is indicative of superior product quality because it reduces the degree of structural degradation caused by drying [33]. The effects of different drying temperatures on the rehydration ratios of sea buckthorn in the third-drying stage are shown in Figure 2a.…”

Pore development in viscoelastic foods during drying

“…Pore formation occurs in several food applications: (a) spray drying of maltodextrin, where pore formation occurs via cavitation, if a gel-like skin is formed, 4 (b) pore formation in pre-dried vegetable snacks via an instant pressure drop (DIC), 23 and (c) pore formation during hot air drying of vegetables, as induced by case hardening, 10 (d) pore formation during drying of seeds, and (e) puffing of bubbles in heated starchy snacks. 10,24 The interplay between the pressure drop and time development of porosity also plays a role in the DIC treatment of non-predried mushrooms, 25 but this system is different from the above, as the mushroom is a porous system with high interconnectivity, while the other systems have closed pores. It is shown in multiple publications 14,15,[26][27][28][29] that these food materials must be treated as viscoelastic materials, which dissipated elastic stresses at a time scale shorter or comparable to the time scales of drying.…”