Chitosan-based Maillard self-reaction products: Formation, characterization, antioxidant and antimicrobial potential

Abstract

urrently, artificial preservatives are widely used to ensure microbial food safety, as well as its nutritional value and organoleptic characteristics. At the same time, the search for natural antimicrobials is relevant due to consumers’ concern on health issues. Moreover, the widespread use of conventional antibiotics is leading to the emergence of multidrug-resistant bacteria, reinforcing the research focus on the natural antimicrobial agents in the food industry (Quinto et al., 2019). Chitosan is actively used in medicine (Bakshi et al., 2020; Muzzarelli et al., 2014; Verlee et al., 2017) due to its unique physicochemical, biological, ecological and physiological properties: non-toxicity, biocompatibility, biodegradability, stability in the natural environment, antibacterial activity etc. However, there are some drawbacks limiting the use of chitosan: low solubility in water and physiological media and, as a result, insufficient bioavailability, weak antioxidant activity, complicated methods for obtaining polysaccharide derivatives. In general, the antioxidant activity of chitosan is significantly inferior to classical antioxidants, which also limits its use as a substrate for the creation of pharmaceuticals and dietary supplements (Yang et al., 2020). Chemical modification of chitosan, including by conjugation with molecules of biologically active substances (oxycinnamic acids, proteins, etc.), makes it possible to obtain polymer derivatives with improved characteristics (Varlamov et al., 2020). Thus, the introduction of additional functional groups into chitosan leads to enhance its antiviral and antibacterial activity, increase its immunostimulatory, adjuvant, adaptogenic, antihypoxic, radioprotective and hemostatic effects (Bakshi et al., 2020; Muzzarelli et al., 2014; Verlee et al., 2017), as well as improve its antioxidant (Alexandrova et al., 2016) and mucoadhesive (Ways et al., 2018) properties. The conjugation of chitosan is most often carried out by the standard carbodiimide method (Nikalaichuk et al., 2022), the drawback of which is the high cost of reagents for carbodiimide activation of functional groups. At the same time, carbonyl-amine interactions can occur under the influence of temperature, for example, when amino acids are heated with sugars, i.e. melanoidin formation or the Maillard reaction (MR). The amino groups of chitosan can react with the carbonyl group of sugar to form of Maillard reaction products (MRPs) (Chang et al., 2011; Kanatt et al., 2008; Rao et al.,