Characterization of Antimicrobial-bearing Liposomes by ζ-Potential, Vesicle Size, and Encapsulation Efficiency

Abstract

Liposome entrapment may improve activity of protein or polypeptide antimicrobials against a variety of microorganisms. In this study, ability of liposomes to withstand exposure to environmental and chemical stresses typically encountered in foods and food processing operations were tested. Liposomes consisting of distearoylphosphatidylcholine (PC) and distearoylphosphatidylglycerol (PG), with 0, 5, or 10 μg/ml of the antimicrobial peptide nisin entrapped, were exposed to elevated temperatures (25-75°C) and a range of pH (5.5-11.0). Ability of liposomes to maintain integrity was assessed by measuring the encapsulation efficiency (EE), z-potential, and particle size distribution of liposomes. Distearoylphosphatidylcholine, PC/PG 8:2, and PC/PG 6:4 (mole fraction) liposomes retained between~70-90% EE despite exposure to elevated temperature and alkaline or acidic pH. Particle size of liposomes averaged between 100 and 240 nm depending on liposome preparation. Liposomal surface charge depended primarily on phospholipid composition and changed little with inclusion of nisin. Surface charge was not affected by temperature for PC and PC/PG 8:2 but decreased for PC/PG 6:4 liposomes. Our results suggest that liposomes containing nisin may be suitable for use as antimicrobial-active ingredients in low-or high-pH foods subjected to moderate heat treatments.

Influence of Lipid Composition, pH, and Temperature on Physicochemical Properties of Liposomes with Curcumin as Model Drug

“…The magnitude of the negative ZP for DPPC DPPG liposomes was in between the values for DPPG and SPC/DPPC liposomes. Negatively charged liposomes are expected to be more stable than zwitterionic liposomes 45 . The independence of the ZP on the pH of the medium indicates that varying pH did not significantly alter the electrostatic interaction between phospholipid molecules 46 .…”

The encapsulation of flavourzyme in nanoliposome by heating method

“…Recently, liposome, spherical particles with sizes at the range of the nanometer to micrometer formed by polar lipids (Charcosset 2009;Taylor et al 2005) has received special attention in the literature (Mozafari et al 2008a, b). Liposome technology has generated much interest in food industry for the encapsulation of different materials such as ferrous glycinate (Ding et al 2011), ferrous sulfate (Xia and Xu 2005), antioxidant (Mozafari et al 2006), nisin (Taylor et al 2007;Laridi et al 2003;Colas et al 2007) β-galactosidase (Rao et al 1994) and different cheese accelerated enzymes such as lipase (Kheadr et al 2002), Nutrease (Alkhalaf et al 1989), chymotripsine (Laloy et al 1998;Dufour et al 1996), chymosine (Picon et al 1994), neutral protease (Picon et al 1995), cyprosine (Picon et al 1996) bacterial and fungal protease, Flavourzyme and palatase . Different methods such as reverse-phase evaporation, dehydration-rehydration, microfludization technique and proliposome usage have been applied for liposome manufacturing with a variation of EE (%) ranging from 10 to 40.3 %.…”

Characterization of lyophilized liposomes produced with non-purified soy lecithin: a case study of casein hydrolysate microencapsulation

“…A wide range of applications is possible in food using these versatile colloidal systems, and an increasing number of studies are available in the literature. These studies cover a large variety of substances, including enzymes (Benech et al, 2003;Kheadr et al, 2003;Rodriguez-Nogales and López, 2006), protein hydrolysates (Morais et al, 2003), antioxidants (Kostecka-Gugala et al, 2003;McNulty et al, 2007), antimicrobials (Were et al, 2004;Taylor et al, 2007), minerals (Ucich et al, 1999;Kosajaru et al, 2006) and vegetable extracts and essential oils (Gortzi et al, 2007;Gortzi et al, 2008;Takahashi et al, 2008;Detoni et al, 2009;Yoshida et al, 2010).…”