Oxylipin concentration, but not fatty acid composition, is altered in human donor milk pasteurised using both thermal and non-thermal techniques

Abstract

Human donor milk (DM) is Holder pasteurised (62·5°C, 30 min) to ensure its microbiological safety for infant consumption. In low-resource settings, flash heating is used to pasteurise milk. Although there is considerable interest in non-thermal alternatives (high hydrostatic pressure processing (HHP) and UVC irradiation) for pasteurisation, their effect on the fatty acid composition is not well understood. Of particular interest is the effect of pasteurisation on the generation of oxylipins. DM from eight mothers containing bacteria >5 × 107 colony-forming units/l was used. In a paired design, each pool of milk underwent four pasteurisation techniques: Holder; flash heating; UVC (250 nm, 25 min) and HHP (500 MPa, 8 min). Fatty acids were quantified by GC-flame ionisation detection and oxylipins derived from arachidonic acid; 18-carbon PUFA (α-linolenic acid, linoleic acid and γ-linolenic acid) and EPA/DHA were measured by liquid chromatography-tandem MS in aliquots of raw and processed milk. There were no significant changes to the composition of fatty acids following all pasteurisation techniques compared with raw milk. The n-6:n-3 ratio remained constant ranging from 6·4 to 6·6. Several arachidonic acid-derived oxylipins were highest post-UVC and elevated post-HHP compared with raw milk. Several oxylipins derived from 18-carbon PUFA (linoleic and α-linolenic acids) were elevated in UVC-treated milk. EPA/DHA-derived oxylipins were on average, unaffected by pasteurisation. Although some PUFA-derived oxylipins were increased following UVC and HHP, no method affected the fatty acid composition of human DM. Further research is needed to determine if varying levels of oxylipins in human DM as a result of processing can potentially mediate cellular signalling; proliferation and apoptosis, especially important for preterm infant development.

Effects of industrial heat treatments on bovine milk oxylipins and conventional markers of lipid oxidation

“…Our results are in general agreement with a study by Pitino et al, which reported significant reductions in human milk oxylipins following thermal (holder pasteurization, flash heating) and non-thermal treatments (High Hydrostatic Pressure and UVC) [33]. The authors reported minimal changes (not statistically significant) in the concentrations of LA and ALA metabolites following Holder (62.5°C for 30 min) and flash heating pasteurization compared with raw milk, consistent with our findings showing no significant changes in LA-and ALA-derived oxylipins as the result of BP (same processing conditions were used in both studies, 62.5°C for 30 min).…”

“…The authors reported minimal changes (not statistically significant) in the concentrations of LA and ALA metabolites following Holder (62.5°C for 30 min) and flash heating pasteurization compared with raw milk, consistent with our findings showing no significant changes in LA-and ALA-derived oxylipins as the result of BP (same processing conditions were used in both studies, 62.5°C for 30 min). However, the significant reduction in LA and ALA metabolites observed in our study as a result of the HTST treatment was not observed by Pitino et al [33]. In addition to different starting materials used in both studies (human vs. bovine milk), different conditions were used for HTST treatment, which could explain the different outcomes.…”

Distribution of Free and Esterified Oxylipins in Cream, Cell, and Skim Fractions of Human Milk

“…An interest in human milk bioactive lipid Supporting information Additional supporting information may be found online in the Supporting Information section at the end of the article. mediators has emerged since oxidized metabolites of polyunsaturated fatty acids (PUFA), known as oxylipins, have been detected in human breast milk (Pitino et al, 2019;Robinson et al, 2017;Weiss et al, 2013;Wu et al, 2016). Oxylipins have been shown to regulate infant development and immunity.…”

“…Human milk provides nutritional, immunological, and neurodevelopmental benefits for newborn infants (Harding et al, 2017). An interest in human milk bioactive lipid mediators has emerged since oxidized metabolites of polyunsaturated fatty acids (PUFA), known as oxylipins, have been detected in human breast milk (Pitino et al, 2019; Robinson et al, 2017; Weiss et al, 2013; Wu et al, 2016). Oxylipins have been shown to regulate infant development and immunity.…”

“…Previous studies have measured and detected free (i.e. unbound) oxylipins in whole or skim milk (Alexandre‐Gouabau et al, 2018; Arnardottir et al, 2016; Pitino et al, 2019; Robinson et al, 2017; Weiss et al, 2013; Wu et al, 2016). However, evidence from rodent and human studies suggests that in tissues or plasma, the majority of oxylipins are bound (i.e.…”