Dextran-Based Edible Coatings to Prolong the Shelf Life of Blueberries

Abstract

The development of edible films and coatings in the food packaging industry presents one of the modern strategies for protecting food products and ensuring their freshness and quality during their shelf lives. The application of microbial polysaccharides to the development of food package materials, as an alternative option to the commonly used plastic materials, is both economic and environmentally favorable. New edible films were developed using dextran from lactic acid bacterium Leuconostoc mesenteroides T3, and additionally plasticized by different concentrations of polyglycerol. The best tensile strength of the films was obtained using a formulation that contained 10 wt% of polyglycerol, which corresponded to a value of 4.6 MPa. The most flexible formulation, with elongation at break of 602%, was obtained with 30 wt% of polyglycerol. Water vapor permeability values of the films synthesized in this study were in the range of (3.45–8.81) ∗ 10−12 g/m s Pa. Such low values indicated that they could be efficient in preventing fruit from drying out during storage. Thus, the film formulations were used to coat blueberries in order to assess their quality during a storage time of 21 days at 8 °C. The results showed that dextran/polyglycerol films could be efficient in extending the shelf life of blueberries, which was evidenced by lower weight loss and total sugar solids values, as well as a delay in titratable acidity, in comparison to the uncoated blueberries.

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“…During the maturation stage, metabolic reactions cause an increase in the macromolecular content such as the sugars during the storage time. 32 The TSS of both tomatoes and blueberries with the AC-G1 formulation was significantly lower than that of the uncoated samples (Figures 3D and S3d). There was a sharp increase in the TSS of uncoated tomatoes at day 11, which dropped back to its values similar to that of day 10.…”

Beneficial Effects of Sodium Nitroprusside on the Aroma, Flavors, and Anthocyanin Accumulation in Blood Orange Fruits

“…The total soluble solid (TSS) content in pulp was determined at 25 °C, according to the refractive index measured with a digital refractometer (Model DP0101, Ningbo Better Technology Comp., Ningbo, China), and the result was expressed in °Brix. Titratable acidity (TA) in pulp was determined by titration with 0.1 M NaOH [ 22 ]. The absorbance of the tannin extract in the pulp was measured with a UV–Vis Spectrophotometer (DU-8600R, Drawell Instrument Comp., Chongqing, China) at a wavelength of 525 nm, and the tannin content was expressed as tannic acid equivalents [ 23 ].…”

Using Nanotechnology for Enhancing the Shelf Life of Fruits

“…Edible coatings are 1) [10]). also very operative in lowering TSS, or we can say in lowering the ripening rates of fruit and vegetable products [24]. Edible coatings and films (ECF) are employed as matrixes for including antimicrobial nanoparticles (NPs), and then they are used on fruits and vegetables to increase their shelf life and enhance quality in storage.…”