Hot-Air Flow Rolling Dry-Blanching Pretreatment Improves the Drying Quality of Acanthopanax sessiliflorus by Increasing the Drying Rate and Inactivating Enzymes

Abstract

The processing of Acanthopanax sessiliflorus has attracted interest due to its health benefits. In this work, an emerging blanching technology, called hot-air flow rolling dry-blanching (HMRDB), was employed to treat A. sessiliflorus before drying. The effects of varied blanching times (2–8 min) on enzyme inactivation, drying characteristics, bioactive compound retention, and microstructure were examined. The results demonstrated that blanching for 8 min rendered polyphenol oxidase and peroxidase nearly inactive. The blanching process reduced the drying time of samples by up to 57.89% compared to an unblanched sample. The Logarithmic model showed good fitting performance for the drying curves. The total phenolic and flavonoid content of the dried product increased as blanching time increased. The total anthocyanin content of the samples blanched for 6 min was 3.9 times higher than that of the unblanched samples, and 8 min of blanching produced the greatest DPPH• and ABTS• scavenging capabilities. The retention of active compounds in a dried product is a result of the inactivation of enzymes and a reduced drying period. Changes in the porous structure of the blanched samples would be responsible for the accelerated drying rate, according to microstructural analysis. These results indicate that HMRDB enhances the drying process and improves drying quality when applied to A. sessiliflorus before drying.

Effects of Different Drying Methods on Drying Characteristics, Microstructure, Quality, and Energy Consumption of Apricot Slices

“…This may have been due to the formation and sublimation of crystals inside the material during VFD, which destroyed the cell structure and increased the extractable antioxidant active substances. Xu [48] and An et al [22] obtained the same results while studying VFD-treated okra and soybeans. The DPPH and FRAP free radical scavenging abilities of dried samples were stronger than those of fresh samples.…”

“…Water activity is a crucial index affecting the storage stability of dried fruits. When the water activity of dried fruits is <0.6, microbial growth and chemical reactions are effectively inhibited [22]. As the water content of fresh apricots is high, their respiration intensity is high and water activity is relatively high (i.e., 0.954 ± 0.019).…”

“…A slightly modified version of the method described by An et al [22] was used to prepare the total phenol extract. A 1 g sample was placed in a mortar and ground with an appropriate amount of 80% methanol solution.…”

“…Following the methods described by An et al [22], the total phenolic extract of the sample was prepared. The antioxidant capacity of the sample was determined by evaluating its scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and its ferricreducing antioxidant power (FRAP).…”

Effects of different drying methods on the contents of active ingredients of Saposhnikovia divaricata (Turcz.) Schischk and optimization of the drying process by response surface methodology

“…However, its drying time is long and it has a certain influence on the active ingredients of dried products. 24,25 Freeze-drying is performed in a low-temperature vacuum environment, effectively inhibiting the activity of certain microorganisms and biological enzymes. It can retain the tissue structure and medicinal value to a high extent.…”