Chitosan-glucose derivative as effective wall material for probiotic yeasts microencapsulation.

A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.

Biotechnological use of dairy by-products for the production and microencapsulation of the food preservative enterocin CRL35.

Bacteriocins from Gram-positive bacteria have been proposed as natural food preservative and there is a need for large-scale production for commercial purposes. The aim of the present work is to evaluate whey, a cheese industrial by-product, for the production and microencapsulation of enterocin CRL35. Whey proved to be a promising basal medium for bacterial growth although the bacteriocin production was quite low. However, it could be much favored with the addition of yeast extract at concentrations as low as 0.5%. Besides improving bacteriocin production, this peptide was successfully microencapsulated by spray drying using whey protein concentrate and a chitosan derivative as wall materials. Microcapsules averaging 10 ± 5 µm diameter were obtained, with good structural integrity and high antimicrobial activity with a stability of at least 12 weeks at 4°C. In summary, sustainable bacteriocin production and microencapsulation was achieved recycling whey or its derivatives. In addition, the formulation owns high antimicrobial activity with a long shelf life. The development of a food preservative may represent a green solution for handling whey.

Bioactive Ingredients Obtained from Agro-industrial Byproducts: Recent Advances and Innovation in Micro- and Nanoencapsulation.

The agro-industry produces numerous byproducts that are currently underused, and its waste contributes to environmental pollution. These byproducts represent an important and economical source of bioactive ingredients, which can promote the sustainable development of high-value-added functional foods. In this context, micro- and nanoencapsulation systems allow for the incorporation and stabilization of the bioactive agents in foods. This perspective will review recent advances in the use of agro-industrial byproducts as a source of bioactive agents. In addition, the latest advances in micro- and nanoencapsulation to improve the stability, solubility, and bioaccessibility of bioactive agents as functional food ingredients are exposed.

Antioxidant and cytoprotective effect of peptides produced by hydrolysis of whey protein concentrate with trypsin.

Whey protein is one of the most relevant co-products manufactured by the dairy industry and it is a powerful environmental pollutant. Therefore, the enzymatic hydrolysis of whey protein concentrate (WPC 35) to produce antioxidant peptides is an innovative approach which can provide added value to whey. The WPC 35 hydrolysis with trypsin was carried out for 4.31 h at 41.1 °C with an enzyme/substrate ratio of 0.017. Under such hydrolysis conditions, the peptides produced have the highest radical scavenging activity and cytoprotector effect. The WPC hydrolysate and a permeate ≤3 kDa were characterized by SDS-page, RP-HPLC and MALDI-TOF-MS. Furthermore, O2•- and HO• scavenging activity and the cytoprotective effect against a stress agent in epithelial cells of the rat ileum (IEC-18) were determined. In this study, strong antioxidant and cytoprotective peptides were obtained from a low-cost dairy industry product, which could improve consumers' health when used as functional ingredients.

Soy genistein administered in soluble chitosan microcapsules maintains antioxidant activity and limits intestinal inflammation.

We used water-soluble Chitosan obtained by Maillard reaction with glucosamine to microencapsulate soy genistein (Ge) and preserve its biological activity for oral administration. Release of Ge was pH dependent with a super Case II mechanism at pH 1.2 and an anomalous transport with non-Fickian kinetics at pH 6.8. Microencapsulated Ge retained its antioxidant properties in vitro and its daily administration to mice attenuated clinical signs of acute colitis, limited inflammatory reaction and reduced oxidative stress and tissue injury as well. Remarkably, after feeding microencapsulated Ge the production of IL-10 in colonic tissue was restored to levels of untreated controls. According to statistical multivariate analysis, this cytokine was the parameter with the highest influence on the inflammatory/oxidative status. Microencapsulation of Ge with derivatized Chitosan becomes an interesting alternative to develop therapeutic approaches for oxidative inflammatory diseases; our findings suggest that the soy isoflavone could be incorporated into any functional food for application in intestinal inflammation.

Physicochemical characterization of water-soluble chitosan derivatives with singlet oxygen quenching and antibacterial capabilities.

New water-soluble chitosan derivatives (WSCh) were obtained by Maillard reaction (MR) between glucosamine (GA) with both low and medium molecular weight chitosans (Ch). The WSCh showed larger solubility than the respective Ch, while their deacetylation degree (DD) decreased by approximately 12%. Infrared spectroscopy experiments of WSCh confirmed the formation of imine bonds after MR with intensified pyranose structure, and sugar molecules as polymer branches. However, a 6-times reduction of the molecular weight of WSCh was measured, indicating the breakdown of the polysaccharide chain during the MR. The polysaccharides quenched singlet molecular oxygen (1O2), with rate quenching constants correlating with the DD value of the samples, suggesting the important role of amino groups (-NH2) in the deactivation of 1O2. Additionally, all polysaccharides presented antimicrobial activity against pathogenic bacteria, e.g. Staphylococcus aureus, Escherichia coli, Salmonella sp., Enterococcus faecalis and Listeria ivanovii, as tested by their minimum inhibitory concentration (MIC). This way we obtained new water-soluble polysaccharides, with similar functional properties to those presented by native Ch, enhancing its potential application as carrier material for bioactive compounds.