title: Molecular Structure of Lactoferrin Influences the Thermal Resistance of Lactococcal Phages.
abstract: The protective effect of whey proteins on phages of lactic acid bacteria during heat treatment limits the recycling of whey proteins into cheese. To investigate this protective effect, we used lactoferrin (LF) as a whey protein model as a result of its unique physicochemical properties and its antiviral activity. First, the thermal inactivation of lactococcal thermoresistant virulent phage P1532 was measured in LF at 95 °C and under different pH values. Phage inactivation results revealed a strong protective effect of LF on P1532 phage at pH 5 but none at pH 7. The structural conformational changes of LF were then monitored by Fourier transform infrared and circular dichroism spectroscopies. Spectroscopic analysis showed that LF was unfolded after heating at pH 7, while it preserved its tertiary and secondary structures when heated at pH 5. There is a direct correlation between the thermal stability of LF and its ability to protect P1532 phage from heat treatment.
authors.forename: Hany
authors.initials: H
authors.lastname: Geagea
authors.affiliation: Department of Food Science and Nutrition, National Research Centre , Cairo, Egypt.
authors.forename: Ahmed
authors.identifier: http://orcid.org/0000-0002-7612-6043
authors.initials: A
authors.lastname: Gomaa
authors.affiliation: Coopérative Agropur , Saint-Hubert, Québec J3Z 1G5, Canada.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Remondetto
authors.forename: Sylvain
authors.identifier: http://orcid.org/0000-0002-2832-5101
authors.initials: S
authors.lastname: Moineau
authors.forename: Muriel
authors.initials: M
authors.lastname: Subirade
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000737:chemistry* / Q000502:physiology; D002611:Cheese / Q000032:analysis / Q000382:microbiology; D005285:Fermentation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D013294:Lactococcus lactis / Q000378:metabolism / Q000821:virology; D007781:Lactoferrin / Q000737:chemistry*; D008892:Milk / Q000378:metabolism / Q000382:microbiology; D017433:Protein Structure, Secondary; D000067816:Whey Proteins / Q000378:metabolism
chemical_list: D000067816:Whey Proteins; D007781:Lactoferrin
keywords: heat treatment; lactococcal phages; lactoferrin; molecular structure; pH; protective effect