Sm. Pons et al., EVALUATION BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF THE HYDROLYSIS OF HUMAN-MILK TRIACYLGLYCERIDES DURING STORAGE AT LOW-TEMPERATURES, Journal of chromatography, 823(1-2), 1998, pp. 467-474
Citations number
19
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
The effect of various storage methods on the stability of the triacylg
lyceride fraction of human milk was evaluated. Samples were treated as
follows: Group I - stored at -20 degrees C for 4 months, group II - h
eated for 1.5 min at 80 degrees C and stored at -20 degrees C for 4 mo
nths, group III - stored at -80 degrees C for 4 months and thawed rapi
dly at room temperature (25 degrees C) just before analysis and group
IV - stored at -80 degrees C for 2 months, thawed rapidly at room temp
erature (25 degrees C), then stored at -80 degrees C for a further 2 m
onths and finally thawed rapidly at 25 degrees C just before analysis.
The absence of hydrolysis products in group II and group III indicate
d that these storage procedures were satisfactory even when samples we
re rapidly thawed for a short time (group IV). Only storage at -20 deg
rees C without previous heat treatment led to the hydrolysis of triacy
lglycerides and the appearance of free fatty acids (group I). On the o
ther hand, the effect that freezing and thawing had over the lipolysis
grade was studied. Samples were treated as follows: group V - stored
at -20 degrees C for 2 months, thawed slowly at refrigerator temperatu
re (5 degrees C), held at this temperature for one week and stored for
a further month at -20 degrees C. Freezing and thawing activated lipo
lysis and increased the production of free fatty acids, monoacylglycer
ides and diacylglycerides. Milk samples were analyzed by reversed-phas
e HPLC with a ternary gradient of acetonitrile-dichloromethane-acetone
and an evaporative Light-scattering detector. (C) 1998 Elsevier Scien
ce B.V. All rights reserved.