Abstract
Natural extracts possess several kinds of antioxidants (anthocyanins, betalains, thymol, carvacrol, and resveratrol) that have also demonstrated antimicrobial properties. In order to study these properties, extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and resveratrol (from grapes) were obtained. Growth inhibition tests of mesophilic aerobes, coliforms, and fungi were conducted in films prepared from the extracts in accordance with Mexican Official Norms (NOM). Optical properties such as transparency and opacity, mechanical properties, and pH were also analyzed in these materials. The films with beetroot, cranberry, and blueberry extracts demonstrated the best antimicrobial activity against various bacteria and fungi in comparison with unmodified chitosan–starch film. This study shows that the addition of antioxidants improved the antimicrobial performance of these films. It was also found that antimicrobial properties are inherent to the films. These polymers combined with the extracts effectively inhibit or reduce microorganism growth from human and environmental contact; therefore, previous sterilization could be unnecessary in comparison with traditional plastics. The presence of extracts decreased transmittance percentages at 280 and 400 nm, as well as the transparency values, while increasing their opacity values, providing better UV–VIS light barrier properties. Despite diminished glass transition temperatures (Tg), the values obtained are still adequate for food packaging applications.
Highlights
In recent decades, human health has been increasingly threatened by microbiological contamination; this can be seen in the spread of food-borne infections and communicable diseases that has occurred recently
Chitosan is obtained by the N-deacetylation of chitin, which is the second most abundant natural polysaccharide in nature
The innovative purpose of this study is to intensify the biocidal properties of chitosan–starch films against food-contaminant-indicator microorganisms by using organic and nontoxic materials, such as natural extracts, with demonstrated antimicrobial properties that are compatible with the matrix film
Summary
Human health has been increasingly threatened by microbiological contamination; this can be seen in the spread of food-borne infections and communicable diseases that has occurred recently. Several research studies have shown that chitosan and other several natural antioxidants are natural biocides that are promising candidates for solving this problem [1]. Chitosan is obtained by the N-deacetylation of chitin, which is the second most abundant natural polysaccharide in nature. Due to its good biocompatibility, it is widely applied in the pharmaceutical, agricultural, food, nutritional, and biomedical industries, in addition to other applications such as sewage treatment. Chitosan-based materials can be used as degradable and edible films or coatings. Starch has been used to produce biodegradable films, partially or totally substituting plastic polymers, because of its low cost and renewability. The broad applications of pure starch films are limited by the water solubility and fragility of the material [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
