Behavior of protein-polysaccharide conjugate-stabilized food emulsions under various destabilization conditions.

The sensitivity of protein-stabilized emulsions to flocculation, coalescence, and phase separation under destabilization conditions (i.e., heating, aging, pH, ionic strength, and freeze-thawing) may limit the widespread use of proteins as effective emulsifiers. Therefore, there is a great interest in modulating and improving the technological functionality of food proteins by conjugating them with polysaccharides, through the Maillard reaction. The present review article highlights the current approaches of protein-polysaccharide conjugate formation, their interfacial properties, and the behavior of protein-polysaccharide conjugate stabilized emulsions under various destabilization conditions, including long-term storage, heating and freeze-thawing treatments, acidic conditions, high ionic strength, and oxidation. Protein-polysaccharide conjugates are capable of forming a thick and cohesive macromolecular layer around oil droplets in food emulsions and stabilizing them against flocculation and coalescence under unfavorable conditions, through steric and electrostatic repulsion. The protein-polysaccharide conjugates could be therefore industrially used to design emulsion-based functional foods with high physicochemical stability.

Development and characterization of antioxidant and antimicrobial edible films based on chitosan and gamma-aminobutyric acid-rich fermented soy protein.

In this study, biocomposite edible films of gamma-aminobutyric acid (GABA)-rich fermented soy protein (GABA-RFSP) with different chitosan concentrations (2, 2.5, and 3%) were prepared. The GABA-rich edible films based on 2.5 % chitosan had the highest a*, b*, browning index, and absorbance at 420 nm compared to other films, indicating the occurrence of Maillard reaction during film-formation period. The Maillard reaction fabricated 2.5 % chitosan-based edible films with high tensile strength and elongation at break, in conjugation with a more smooth, compact, and homogeneous surface with less pores or cracks, which was confirmed by Field emission scanning electron microscopy. The films also showed considerable antioxidant and antimicrobial activities. The covalent linkages between chitosan and GABA-RFSP, and the presence of GABA in the edible films were confirmed by Fourier transform infrared spectroscopy. The results suggested the potential use of GABA-RFSP and chitosan to fabricate novel bioactive-loaded edible films for food packaging purposes.

Antioxidant potential and antimicrobial activity of chitosan-inulin conjugates obtained through the Maillard reaction.

Chitosan (1%) was glycated with inulin (0.5, 1, and 2%) via the Maillard reaction at various initial pH values (5, 5.5, and 6). Higher pHs led to a greater pH drop and increase in the intermediate products and browning intensity (BI). The chitosan-inulin conjugates were then classified into three levels of low, medium, and high BI through K-means clustering in order to investigate the effect of BI development on the antioxidant and antimicrobial attributes of the conjugates. Covalent linkage between chitosan and inulin was confirmed by fourier transform infrared spectroscopy. High BI chitosan-inulin conjugate had significantly higher antioxidant property compared to chitosan and other conjugate fractions. In addition, the conjugates obtained at low pH values mainly presented greater antimicrobial activities than those prepared at high pHs. It can be concluded that chitosan-inulin Maillard-born conjugates can be used as novel antioxidant and antimicrobial prebiotic-based ingredients for food applications.