No abstract

Research background. The use of gel-based systems, as a novel method for the delivery of natural antimicrobial, antioxidant, and bioactive compounds is a developing innovative solution for the food industry. This research aimed development of multifunctional active edible gels based on gelatine and its composites with improved mechanical properties. Experimental approach. Antilisterial and bioactive composite gels showing different physical and active properties than classical gelatine gel were developed by loading lysozyme and green tea extract into gelatine/starch and gelatine/wax composite gels. The gels were characterized for their mechanical properties, swelling profiles, colour, release profiles, and antimicrobial and bioactive properties. Results and conclusions. Gelatine/wax gels showed 1.3 to 2.1-fold higher firmness and cutting strength than gelatine and gelatine/starch composite gels that had similar firmness and cutting strengths. Work to shear of both composite gels was 1.4 to 1.9-fold higher than that of gelatine gel. The gelatine/starch gel showed the highest water absorption capacity. Green tea extract reduced soluble lysozyme in gels, but composite gels contained higher soluble lysozyme than gelatine gel. All the gels with lysozyme inhibited Listeria innocua growth in the broth media while green tea extract showed antilisterial activity only in gelatine/wax gels. Gels with green tea extract showed antioxidant, antidiabetic (α-glucosidase, and α-amylase inhibition), antihypertensive (angiotensin-converting enzyme inhibition), and antiproliferative activities (on Caco-2 human colon carcinoma cells). However, gelatine and gelatine/wax gels showed the highest antioxidant and antidiabetic activity. The gelatine/wax gels prevented phenolic browning while green tea extract in other gels showed moderate or extensive browning. Novelty and scientific contribution. This work clearly showed the possibility of improving mechanical properties, and modifying water absorption and controlled release profiles of gelatine gels using gelatine/starch and gelatine/wax composites. The novel composite gels reduced browning of incorporated polyphenols and showed antilisterial and bioactive properties.