In order to better manage the peeling degree and avoid unnecessary losses, the current work aimed to explore the peeling mechanism of a novel peeling technology, high-humidity hot air impingement blanching (HHAIB). The relationships between HHAIB peeling performance and the changes in skin temperature, skin structure, water state, pectin fractions content, and skin mechanical properties of tomatoes were analyzed. Results showed, after HHAIB treatment, the epicuticular wax was disrupted, the skin exhibited more and longer random cracks, the degradation of inner skin tissue was observed by transmission electron microscopy, the free water percentage increased resulting in water loss in the whole tomato, the water-soluble pectin contents decreased in tomato fleshes, while the contents of chelate-soluble pectin and sodium-carbonate-soluble pectin increased. HHAIB heating reduced the elongation at break, and increased Young\'s Modulus of tomato peel. This study revealed the HHAIB peeling mechanism and provided new insights for developing HHAIB peeling technology.

BACKGROUND: Peeling of crayfish is a very important process in production. Crayfish peeling by machine can increase production efficiency and enhance safety in the production process. The tight muscle-shell attachment causes difficulty in peeling freshly caught crayfish. However, few studies have explored the changes in crayfish quality under favorable shell-loosening treatments.
RESULTS: In this study, the shell-loosening properties of crayfish and changes in crayfish quality, microstructure and protein fluorescent features were investigated after high hydrostatic pressure (HHP) treatment. New methods were established to measure the peeling performance of crayfish, which are peelability and meat yield rate (MYR). The normalization of peelability and MYR were verified by different weights of crayfish tails and different treatments. The peeling effect of HHP-treated crayfish was evaluated by a new quantitative measurement method, and MYR was calculated. The results showed that all the HHP treatments reduced crayfish peeling work and increased MYR. The HHP treatment provided better crayfish quality in terms of texture and color and enlarged the shell-loosening gap. Among all HHP treatments, 200 MPa treatment exhibited lower peeling work, higher MYR and an expansion of the shell-loosening gap, reaching up to 573.8 μm. At the same time, 200 MPa treatment could maintain crayfish quality.
CONCLUSIONS: The findings outlined above suggest that high pressure is a promising method for loosening crayfish shells. 200 MPa is an optimal HHP treatment condition for crayfish peeling, exhibiting a promising application in industrial processing. © 2023 Society of Chemical Industry.

The terminal toes of adhesive animals are characterized by rigid-flexible coupling, and their structure-function relationship is an urgent problem to be solved in understanding bioinspired adhesive systems and the design of biomimetic adhesive units. In this paper, inspired by the rigid-flexible coupling adhesive system of the gecko toe, a rigid-flexible coupling adhesive unit was designed, the interface strength of the adhesives under different preloads was tested, and the model and analysis method of the compression and peeling process of the rigid-flexible coupling adhesive unit was established. Meanwhile, combined with the experimental test, the effect of the coupling mechanism of the rigid-flexible structure on the interfacial stress and the final peeling force during the compression and peeling process of the adhesive unit was studied. The research found that the length of the adhesive unit L has no apparent effect on the normal peel force of the system within a specific range, and the normal peeling force increases linearly with the increase in the compression force P; while the influence of the inclination angle θ0 of the adhesive unit and the thickness of the rigid backing layer hb on the final normal peeling force of the system presents nonlinear characteristics, when the inclination angle θ0 of the adhesive unit is 5°, and the thickness of the rigid backing layer hb is 0.2 mm or 0.3 mm, the normal peel force and the ratio of adhesion force to preload the system reaches its maximum value. Compared with the flexible adhesive unit, the compressed zone formed by the rigid-flexible coupling adhesive unit during the same compression process increased by 6.7 times, while under the same peeling force, the peel zone increased by 8 times, and the maximum normal tensile stress at the peeling end decreased by 20 times. The rigid-flexible coupling mechanics improves the uniformity of the contact stress during the compression and peeling process. The research results provide guidelines for the design of the rigid-flexible coupling adhesive unit, further providing the end effector of the bionic wall-climbing robot with a rigid-flexible coupled bionic design.

In the process of graphene nanoribbons\' (GNRs) preparation and measurement, mechanical methods such as lifting and dragging are inevitably used to move GNRs, and manipulation of GNRs using these approaches results in intriguing responses such as peeling and sliding. Understanding the mechanical behaviors of GNRs is crucial for the effective use of mechanical deformation as a tool for the measurement and characteristics of low-dimensional material properties. Here, we explore intricate coupling behaviors of peeling and sliding of GNRs under horizontal drag. Using molecular dynamics simulation, we explore effects of lifting height, dragging velocity, length, and orientation of GNRs on mechanical behaviors. We reveal a competition between sliding and peeling of GNRs under horizontal drag and provide a phase diagram. The peeling behavior is found to be originated from the decrease of sliding velocity caused by the sinking of tail atoms. The results not only advance our insightful understanding of the underlying mechanism of different mechanical responses of GNRs but may also guide the precise manipulations of nano surfaces and interfaces.

Peeling of layered materials from supporting substrates, which is central for exfoliation and transfer processes, is found to be dominated by lattice commensurability effects in both low and high velocity limits. For a graphene nanoribbon atop a hexagonal boron nitride surface, the microscopic peeling behavior ranges from stick-slip, through smooth-sliding, to pure peeling regimes, depending on the relative orientation of the contacting surfaces and the peeling angle. The underlying mechanisms stem from the intimate relation between interfacial registry, interlayer interactions, and friction. This, in turn, allows for devising simple models for extracting the interfacial adhesion energy from the peeling force traces.

Traditional food processing techniques can no longer meet the ever increasing demand for high quality food across the globe due to its low process efficiency, high energy consumption and low product yield. This review article is focused on the mechanism and application of Infrared (IR) and ultrasound (US) technologies in physical processing of food. We herein present the individual use of IR and US (both mono-frequency and multi-frequency levels) as well as IR and US supported with other thermal and non-thermal technologies to improve their food processing performance. IR and US are recent thermal and non-thermal technologies which have now been successfully used in food industries to solve the demerits of conventional processing technologies. These environmentally-friendly technologies are characterized by low energy consumption, reduced processing time, high mass-transfer rates, better nutrient retention, better product quality, less mechanical damage and improved shelf life. This work could be, with no doubt, useful to the scientific world and food industries by providing insights on recent advances in the use of US and IR technology, which can be applied to improve food processing technologies for better quality and safer products.

In this paper, the effects and mechanisms of a novel two-step tomato peeling method, hot lye with a post-assistance of ultrasound, were investigated. The present work aims to improve the environmental friendliness of the conventional hot lye tomato peeling method (10% w/v, 97 °C, 45 s). The results showed that 4% (w/v) lye treatment at 97 °C for 30 s with a post-assistance of a 31.97 W/L ultrasound treatment at 70 °C for 50 s achieved a 100% peelability. In this scenario, the peeling yield and lycopene content in the peeled product were significantly higher than the peeling yield and lycopene content with the conventional hot lye peeling method. The present two-step peeling method was concluded with a mechanism of chemico-mechanical synergism, in which the hot lye functions mainly in a chemical way while the ultrasound is a mechanical process. Especially from the lye side, this work first demonstrated that the lye penetrated across the tomato skin via a pitting model rather than evenly. The findings reported in this paper not only provide a novel tomato peeling method with significant environmental benefits but also discover new clues to the peeling mechanism using hot lye.