Application of immobilized lactase in flexible and biodegradable films to obtain milk with low lactose concentration

Abstract

Chitosan films incorporated with TiO2 nanoparticles and immobilized lactase were developed with the objective of hydrolyzing lactose and producing milk with reduced lactose content and with microbiological quality in different reuse cycles. Lactase (3 and 5 ml), crosslinking agents (glutaraldehyde and genipin) and titanium dioxide nanoparticles (0 and 1%) were used in the formulation of the films. The antimicrobial activity, hydrolysis efficiency of UHT milk lactose, operational stability in five reuse cycles, the influence of the films in increasing the acidity of the milk were evaluated. In general, the hydrolysis of lactose by the films occurred in a shorter time at the highest temperature and the films with 5 ml of lactase and with genipin hydrolyzed a greater amount of lactose during more cycles. All films influenced the increase in the acidity of the milk that was in contact with them. Films with low solubility in an aqueous medium were obtained using the crosslinking agents genipin and glutaraldehyde. In view of the results, it was found that the developed films are presented as a good alternative to be applied as milk food packaging, main films with genipin, and 5 ml of lactase, which hydrolyzed 100% lactose in all cycles at both temperatures.