Liposome encapsulation protects bacteriocin-like substance P34 against inhibition by Maillard reaction products

Bacteriocins are biopreservatives with potential to be used in heat processed foods, and liposome encapsulation may offer a protective effect against interaction of these peptides with food compounds. In this work, Maillard reaction products (MRPs) were prepared by heating (90 °C for 7 h) different combinations of sugars and amino acids, and their inhibitory capacity against free and liposome-encapsulated bacteriocin-like substance (BLS) P34 was evaluated. MRPs formed by fructose and glycine had the highest inhibitory capacity against free and encapsulated BLS P43, remaining 50% of initial activity. Liposome encapsulation increased stability of BLS P34 when it was confronted to glucose/glycine, galactose/glycine, sucrose/glycine and glucose/alanine MRPs. Inhibition mostly occurs within the first 24 h of incubation of BLS P34 and MRPs. Inhibitory activity seems to be associated to melanoidin formation and antioxidant capacity of MRPs. The results show that liposome encapsulation of BLS P34 may be an interesting technique to increase the stability of antimicrobial peptides in heat treated foods.