Understanding the effects of chitosan, chia mucilage, levan based composite coatings on the shelf life of sweet cherry.

Sweet cherry (Prunus avium L.) fruits are prone to quality and quantity loss in shelf-life conditions and cold storage due to their short post-harvest life. Until now efforts have been made to extend the shelf life of the sweet cherry. However, an efficient and commercially scalable process remains elusive. To contribute to this challenge, here in this study, biobased composite coatings consisting of chitosan, mucilage, and levan, were applied on sweet cherry fruits and tested for postharvest parameters in both market and cold storage conditions. Results demonstrated that the shelf life of sweet cherries can be extended until the 30th day while retaining important post-harvest properties like decreased weight loss, fungal deterioration, increased stem removal force, total flavonoid, l-ascorbic acid, and oxalic acid. Given the cost-effectiveness of the polymers used, the findings of this study indicate the feasibility of extending the shelf-life of sweet cherries on a larger scale.

Understanding the effects of copolymerized cellulose nanofibers and diatomite nanocomposite on blend chitosan films.

Chitosan films lack various important physicochemical properties and need to be supplemented with reinforcing agents to bridge the gap. Herein, we have produced chitosan composite films supplemented with copolymerized (with polyacrylonitrile monomers) cellulose nanofibers and diatomite nanocomposite at different concentrations. The incorporation of CNFs and diatomite enhanced the physicochemical properties of the films. The mechanical characteristics and hydrophobicity of the films were observed to be improved after incorporating the copolymerized CNFs/diatomite composite at different concentrations (CNFs: 1%, 2% and 5%; diatomite: 10% and 30%). The antioxidant activity gradually increased with an increasing concentration (1-5% and 10-30%) of copolymerized CNFs/diatomite composite in the chitosan matrix. Moreover, the water solubility decreased from 30% for chitosan control film (CH-0) to 21.06% for films containing 30% diatomite and 5% CNFs (CNFs-D30-5). The scanning electron micrographs showed an overall uniform distribution of copolymerized CNFs/diatomite composite in the chitosan matrix with punctual agglomerations.

Natural ß-chitin-protein complex film obtained from waste razor shells for transdermal capsaicin carrier.

In the literature, the produced ß-chitin samples are in powder or flake forms but there is no natural ß-chitin based film. Also, the commercially available transdermal patches are produced from synthetic polymers. In this regard, we produced natural ß-chitin-protein complex (CPC) film from the waste shells of Ensis spp. The obtained natural film was characterized by FTIR, TGA and SEM. Additionally, swelling, thickness, contact angle and antioxidant tests were done to learn more about the films. After production and characterization of the film, capsaicin, which is commonly used for pain relief was loaded into the film. The loading capacity was recorded as 5.79%. The kinetic models were studied in three different pH, then the results were fitted with Higuchi model with high correlation at pH 7.4. After considering all the obtained results, the capsaicin loaded CPC film may be an alternative candidate for transdermal patch instead of the synthetic ones.

Use of sea urchin spines with chitosan gel for biodegradable film production.

In recent years, the film production from natural polymers has considerably increased in food industry as an alternative to the petroleum based synthetic films. Chitosan is one of the most preferred biopolymers for bio-based film production, due to its biocompatibility, biodegradability, antioxidant activity and antimicrobial properties. Because of its hydrophilic properties, chitosan based films dissolve in water, limiting its uses in industry, to overcome this problem; we mixed 200 and 400 mg of the sea urchin spine powder (SUSP) with 20 mL chitosan gel respectively, to obtain a hydrophobic film. The chitosan films prepared with 200 mg SUSP showed a rise in the degree of contact angle from 70.2° to 107° providing hydrophobicity properties. On the other hand, addition of 400 mg of SUSP to chitosan film resulted in a contact angle of 96.1°. Moreover, the antioxidant activity and thermal stability of the films were increased in the presence of SUSP. Fourier Transform Infrared Spectrophotometry results proved the interactions between chitosan and SUSP. Chitosan films have smooth surface while SUSP blended films have rough surface morphology. These results demonstrated that SUSP is needed to improve the properties of chitosan films for usage in food industry.

Effect of different animal fat and plant oil additives on physicochemical, mechanical, antimicrobial and antioxidant properties of chitosan films.

Practical application of chitosan-essential oil blend films is limited due to the uneconomical extraction procedure of essential oils from plants. This study aimed to produce chitosan films blended with low cost and commercially available oils and fats consumed in daily human diet (olive, corn and sunflower oils, butter and animal fats). The study also focused on how physicochemical, biological and mechanical properties of chitosan blend films were influenced by the incorporation of oils and fats with varying unsaturation degrees. Possible interactions of chitosan film matrix with incorporated oils or fats were investigated. Chitosan-olive oil film showed better surface morphology and higher thermal stability than the films with other unsaturated oils. Tensile strength, Young's modulus and elongation at break were improved by 57.2%, 25.1% and 31.7% for chitosan-olive oil film, respectively. Chitosan-olive oil blend film had the highest antibacterial activity (almost equal to that of commercial antibiotic gentamicin). Edible films obtained from by incorporation of natural oils and fats into chitosan can help produce an environmentally friendly packaging material that is low cost and easily manufactured.