Improvement of quality and shelf-life of strawberries with edible coatings enriched with chitosan

Alginate is a naturally occurring polysaccharide used in the bio industry. It is mainly derived from brown algae species. Alginate-based edible coatings and films attract interest for improving/maintaining quality and extending the shelf-life of fruit, vegetable, meat, poultry, seafood, and cheese by reducing dehydration (as sacrificial moisture agent), controlling respiration, enhancing product appearance, improving mechanical properties, etc. This paper reviews the most recent essential information about alginate-based edible coatings. The categorization of alginate-based coatings/film in food packaging concept is formed gradually with the explanation of the most important titles. Emphasis will be placed on active ingredients incorporated into alginate-based formulations, edible coating/film application methods, research and development studies of coated food products and mass transfer and barrier characteristics of the alginate-based coatings/films. Future trends are also reviewed to identify research gaps and recommend new research areas. The summarized information presented in this article will enable researchers to thoroughly understand the fundamentals of the coating process and to develop alginate-based edible films and coatings more readily.

https://www.mdpi.com/2304-8158/7/10/170/pdf/1

Alginate-Based Edible Films and Coatings for Food Packaging Applications.

Effects of alginate edible coating on preserving fruit quality in four plum cultivars during postharvest storage

Sweet cherry fruits harvested at commercial maturity stage were treated with an edible coating based on sodium alginate at several concentrations (1%, 3% or 5% w/v). The coatings were effective on delaying the evolution of the parameters related to postharvest ripening, such as colour, softening and loss of acidity, and reducing respiration rate. In addition, the edible coatings showed a positive effect on maintaining higher concentration of total phenolics and total antioxidant activity, which decreased in control fruits associated with the over-ripening and senescence processes. Results from quality parameters and antioxidant activity suggested that the maximum storability period for control fruits was 8 days at 2 °C plus 2 days at 20 °C, while alginate-coated cherries could be stored with optimal quality and enhanced antioxidant activity up to 16 days at 2 °C plus 2 days at 20 °C.

Alginate Coatings Preserve Fruit Quality and Bioactive Compounds during Storage of Sweet Cherry Fruit

A previously unreported nanocomposite (CMC/GO) high-performance film was prepared by a simple solution mixing-evaporation method. The structure, thermal stability, and mechanical properties of the composite films were investigated by wide-angle X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, thermogravimetry analysis, and mechanical testing. The results obtained from these different studies revealed that CMC and graphene oxide were able to form a homogeneous mixture. Compared with pure CMC, the tensile strength and Young’s modulus of the graphene-based materials were improved significantly upon incorporation of 1 wt% graphene oxide by 67 ± 6 % and 148 ± 5 %, respectively. In addition, the DMA composite films also showed a high storage modulus up to 250 °C.

Eco-friendly synthesis, characterization and properties of a sodium carboxymethyl cellulose/graphene oxide nanocomposite film

Summary
The objective of this study was to determine the effect of sodium alginate and methyl cellulose coatings on the respiration rate, firmness, acidity, pH, total soluble solids and desiccation rate of peaches. Coated and uncoated control fruits were stored at 15 °C and 40% RH. Respiration rate, moisture loss, and changes in firmness, total titrable acidity, pH and total soluble solids of coated and control samples were determined at 3-day intervals. The respiration rate, moisture loss and changes in quality parameters were much lower in coated peaches as compared with the control. While the maximum acceptable shelf-life at 15 °C for control samples was 15 days, the coated samples maintained their acceptability up to 21 and 24 days, respectively, with sodium alginate and methyl cellulose coating. The reduced respiration and transpiration rates as a result of coatings were considered responsible for maintaining the quality and increasing the shelf-life of peaches.

Michelle Marcotte

Papers

Shelf-life extension of peaches through sodium alginate and methyl cellulose edible coatings