Development and Evaluation of Superabsorbent Hydrogels Based on Natural Polymers.

Superabsorbent hydrogels (SAHs) are three dimensional networks formed by polymers that can absorb aqueous solution of over 100% of their initial weight. This work aimed to develop and characterize SAHs of Chitosan/Xanthan gum (CG), Chitosan/Alginate (CA) and controlled Chitosan (C), Xanthan gum (G), and Alginate (A) produced using "onion-like" methodology. The swelling performance, the morphological structure, the crystallinity, and the Fourier transformed infrared spectroscopy characteristics of SAH were used for the characterization of polyelectrolytes complex. Swelling analysis showed that chitosan has a strong influence on the maintenance of hydrogels structure after swelling, mainly in the acid environment (pH = 2). The chitosan hydrogel presented around 3000% of acidic fluid absorption after 24 h. The chitosan:xanthan gum (1:1 and 2:1 named as C1G1 and C2G1, respectively) hydrogels were the best combination regarding swelling performance in an acid environment, reaching 1665% and 2024%, respectively, as well at pH 7.0, presenting 1005% (C1G1) and 667% (C2G1). Scanning electron microscopy analysis showed samples with pores, and with different shapes. The X-ray diffraction showed the presence of a characteristic peak at 2θ = 20° in all developed composition because of the crystalline nature of chitosan. This work shows the possibility of developing eco-friendly biopolymer-based SAHs at a low cost with a good swelling capacity and stability.

Probiotics and their potential applications in active edible films and coatings.

The global market for probiotics has been increasingly growing in recent years guided by the rising consumers' demand for healthy diets and wellness. This has caused food industries to develop new probiotic-containing food products as well as researchers to study specific characteristics of probiotics as well as their effects on human health. Probiotics are defined as live microorganisms that confer a health benefit to the host when administered in adequate quantities. Probiotics have been added to several food products as well as incorporated into biopolymeric matrices to develop active food packaging as an alternative method for controlling foodborne microorganisms, improving food safety, and providing health benefits. This review includes definition of probiotics, description of their effects on human health, discussion on their applications in edible biopolymeric matrices to develop active edible films and coatings, as well as the probiotics-related legislation.