The consumption of fresh-cut apples has grown rapidly due to consumers' increasing willingness to enjoy prepared and ready-to-eat fruits. But fresh-cut apples tend to experience severe enzymatic browning which discourages people to taste. Chitosan (CS) coating containing ascorbic acid (AA) or calcium chloride (CaCl 2) were applied on fresh-cut apples in this work to observe their preservation effects. Their appearance, weight change were evaluated during the storage at room temperature, besides, AA content, soluble solid content were analyzed at the end of storage. CS-CaCl 2 coating has better preservation effect than CS-AA coating when they were applied on fresh-cut apples. CS-CaCl 2 coating showed lower weight loss and higher AA content of apple slices than CS-AA coating. CS-CaCl 2 coating was also good at anti-browning in terms of the appearance of coated apple slices.

The consumption of fresh-cut fruits is limited because of the oxidation browning and pathogenic bacteria's growth on the fruit surface. Besides, crack of the fresh-keeping film may shorten the preservation time of fruit. In this work, polyelectrolyte multilayer (PEM) film was fabricated by layer-by-layer (LBL) electrostatic deposition method. The film was made by carboxy methylcellulose sodium (CMC) and chitosan (CS). The as-prepared PEM film had good anti-oxidative and antibacterial capability. It inhibited the growth of Gram-negative bacteria and the antibacterial rate was more than 95%. The stratified structure and linear increase of the absorbance in the film verified a linear increase of film thickness. The slight scratched film could self-heal rapidly after the stimulation of water whatever the layer number was. Moreover, the film could heal cracks whose width was far bigger than the thickness. The application of PEM film on fresh-cut apples showed that PEM film had good browning, weight loss and metabolic activity inhibition ability. These results showed that the PEM film is a good candidate as edible film in fresh-cut fruits applications.

Self-healing process occurring when a self-healing Co–CS/PAA PEM film is integrated (I), damaged (II), self-healing (III), and self-healed (IV).

In this study, we report highly transparent self-healing films based on Schiff base linkages between DF-PEG and CS via a layer-by-layer technique.

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Healable films with structural color are highly desirable and have a variety of potential applications. However, combining structural color with self-healing properties to obtain new functional materials is a big challenge in current research. Herein, we present the first example of a color tunable, ultrathin film that can self-heal in response to external mechanical abrasion. It is designed based on intermolecular hydrogen bonding interaction; the synthetic strategy involves spin-coating of poly(acrylic acid) (PAA) and chitosan (CS). The successful preparation of ultrathin, healable, structural color films provides a new type of biomimetic material.One of the characteristic features of living systems is structural color, which can be detected in the outer shells of jewel beetles, wings of butterflies and on many other insects.[1] The structural color originates from spectrally selective reflection of visible light from a periodic modulation of refractive index rather than pigment, dye or luminescence. Inspired by natural biological structures, photonic crystals (PhCs), which are composite structures with a periodic arrangement of refractive index in one dimension, [2] two dimensions, [3] and three dimensions, [4] have been designed and fabricated. Recently, they have been gradually applied in a myriad of applications such as optical devices, [5] sensing materials, [6] display technologies, [7] solar cells [8] and so on. [9] One-dimensional photonic crystals (1DPhCs) have the simplest structures and are easy to handle because of their simple structures composed of alternately stacked thin-film layers with high and low refractive indices. [10] The dynamic coloration is generally achieved either by changing the thickness of the multilayers or the refractive index of individual layers through chemical reactions. [11] Although PhCs have substantial potential applications in the development of advanced functional materials, accidental scratches on optical films change the way light is transmitted and can even cause severe light scattering. Such scratches on optical films have to be healed to restore their original optical functions for further applications.[12] Ideally, if we can mimic the living biological systems more closely and endow the materials with self-healing properties, the designed materials will have extended service lives, which can facilitate their maintenance and increase their reliability with stable functionality. [13] However, combining structural color with self-healing property is an enormous challenge, and there is no report on this field to date.In general, polymers have great potential for self-healing due to the high mobility of the polymer chains under physiological conditions. Polyelectrolyte multilayers have a pronounced self-healing effect due to their mobility in response to environmental change. External stimuli such as pH, ionic strength, temperature, light, etc. affect ionization of the functional groups of the polyelectrolytes, which makes the polyelectrolyte multilayers st...

Unhealthy eating is one cause of obesity and some chronic non-communicable diseases. This study introduces self-efficacy and health consciousness to construct an extended health belief model (HBM) to examine the factors influencing healthy eating intentions and behaviors of Chinese residents and explore the moderating effect of perceived barriers and the mediating effect of healthy eating intentions. Through the survey platform “Questionnaire Star”, this study collected quantitative data from 1281 adults, and partial least squares structural equation modeling was used for confirmatory factor analysis, path analysis, importance-performance map analysis, and multi-group analysis. Results showed that perceived susceptibility, perceived severity, perceived benefits, self-efficacy, and health consciousness had a significant positive effect on residents’ healthy eating intentions. Perceived barriers had a significant negative effect on residents’ healthy eating intentions. Healthy eating intentions had a significant positive effect on healthy eating behaviors. Perceived barriers played a significant negative moderating effect between healthy eating intentions and behaviors. Healthy eating intentions had a positive and significant mediating effect. The multi-group analysis showed that extended HBM has relative generalization ability. The extended HBM has good explanatory and predictive power for healthy diet and provides a new framework for understanding the influencing factors of individuals’ healthy eating intentions and behaviors.

Hydrogels are environment sensitive and they were introduced to 1DPhCs to improve the sensitivity in our previous research. In this paper, a new method was developed for quantitative determination of beta-glucan in oats by introducing graphene oxide (GO) hydrogels in one-dimensional photonic crystals (1DPhCs) with a polyaniline (PANI) defect layer. GO hydrogels were synthesized via a one-step hydrothermal method, characterized with scanning electronic microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), and then they were employed as a component to fabricate 1DPhCs using a spin-coating method. Synthesized 1DPhCs combined with Congo red dye were in use for the quantification of beta-glucan. Reflection spectra demonstrated that a linear relationship existed between the photonic band gap and the beta-glucan concentration within 1-10 mg mL À1 . The detection limit for beta-glucan is 0.18 mg mL À1 with a sensitivity of 7.53 nm mL mg À1 . † Electronic supplementary information (ESI) available. See