The Development of a Novel Sodium Alginate-Based Edible Active Hydrogel Coating and Its Application on Traditional Greek Spreadable Cheese

Abstract

The necessity of reducing the greenhouse effect by decreasing the carbon dioxide fingerprint directed the food packaging technology to use biobased raw materials. Alginates, which are derived from brown algae species, are one of the most promising biobased biopolymers for the development of edible active coatings capable of protecting food from oxidation/bacterial spoilage. In this study, sodium alginate, which was plasticized with glycerol and mixed with a biobased thymol/natural halloysite nanohybrid, was used to develop novel edible active coatings. Nanocomposite coatings were also developed in this project by mixing pure halloysite with sodium alginate/glycerol matrix and were used as reference material for comparison reasons. Instrumental analysis indicated a higher compatibility of a thymol/halloysite nanohybrid with a sodium alginate/glycerol matrix compared to pure halloysite with a sodium alginate/glycerol matrix. Increased compatibility resulted in improved tensile properties, water/oxygen barrier properties, and total antioxidant activity. These edible active coatings were applied to traditional Greek spread cheese and showed a reduction in the mesophilic microbial population over one log10 unit (cfu/g) compared to uncoated cheese. Moreover, the reduction in the mesophilic microbial population increased with the increase in halloysite and thymol content, indicating such sodium alginate/glycerol/thymol/halloysite hydrogels as promising edible active coatings for dairy products.

Ions-Induced Alginate Gelation According to Elemental Analysis and a Combinatorial Approach

“…First, alginates are extensively used in different food industries for many aims, e.g., thickening agents, emulsifiers, stabilizers, chelating agents, encapsulations, suspending agents, swelling agents, etc. [28][29][30]. Alginates are also characterized by some medicinal properties, in particular, antitumor, immunomodulatory [31,32] and antioxidant [33] activities, antianaphylaxis [34], anti-inflammatory [35] effects, and exert antihypertensive potential [36].…”

“…The antibacterial and wound-healing properties of alginate hydrogels, as well as the possibility of introducing drugs into their composition, are used for wound healing and the creation of wound dressing [39][40][41]. The possibility of using alginates as food additives formed the basis for the preparation of edible active food packaging films and coatings in the food packaging sector [28,42]. The invention of methods for preparing porous materials led to the design of catalytic systems [43,44] and systems for the targeted delivery of drugs, medicaments, and genes, the creation of capsules for cellular technologies, scaffolds for tissue engineering, etc.…”