Metabolic effects in mice of cream processing: Direct ultra-high-temperature process lowers high-fat-induced adipose tissue inflammation

Abstract

Although UHT heat treatment is being optimized to improve the stability and functional properties of dairy products, its metabolic effects remain scarcely known. As such, we studied the effect of the type of UHT process on lipid metabolism, intestinal barrier, and inflammation in mice. Nine-week-old male C57Bl/6J mice were fed a diet composed of nonlipidic powder mixed with different UHT dairy creams (final: 13% milkfat) for 1 or 4 wk. All creams contained 0.02% of thickener (carrageenan) and were treated via either (1) classical indirect heating process (Th), (2) indirect process at higher temperature (Th+), or (3) direct process by steam injection (ThD). Plasma, epididymal adipose tissue (EAT), and intestine were analyzed. Multivariate principal component analyses were used to identify differential effects of processes. Th+ differed by a globally higher liver damage score compared with that of the other creams. After 4 wk, the duodenal expression of lipid absorption genes fatty acid binding protein 4 (Fatp4) and microsomal triglycerides transfer protein (Mttp) was lower in the Th+ versus Th group. Expression in the colon of tight junction protein zonula occludens 1 (Zo1) and of some endoplasmic reticulum stress markers was lower in both Th+ and ThD versus the Th group. In EAT, ThD had lower gene expression of several inflammatory markers after 4 wk. Some differential effects may be related to heat-induced physicochemical changes of creams. The type of cream UHT process differentially affected metabolic parameters in mice after a 4-wk fat-rich diet, partly due to cream structure. Altogether, direct steam injection process induced the lowest early markers of high-fat-induced metabolic inflammation in EAT.

Metabolic effects in mice of cream formulation: Addition of both thickener and emulsifier does not alter lipid metabolism but modulates mucus cells and intestinal endoplasmic reticulum stress

“…However, to date, no studies have investigated the metabolic effect of dairy UHT cream formulation, no-tably regarding the use of CGN, emulsifier, or both. In a companion study (Milard et al, 2018), we showed that the type of UHT process applied to a cream with CGN differentially affected metabolic parameters in mice after a 4-wk fat-rich diet, partly due to cream structure. Here we studied the intestinal and metabolic effect of cream treated with indirect UHT treatment according to its formulation: (1) without additives (Ctl) or (2) with CGN (0.02%, Th) alone, or (3) also with MAG/DAG ester emulsifier (0.1%, Th/Em).…”

“…This study is part of a wider animal and experimental design aiming to explore the effect of cream heat treatment and additives, which is described in the companion paper (Milard et al, 2018). Animal experiments were carried out in accordance with the Guiding Principles for the Care and Use of Vertebrate Animals in Research and Training and the French Ministère de l'Agriculture (no.…”

“…Of note, the Th group is the same as in our other study on the effect of the type of UHT process applied to cream (Milard et al, 2018). All creams (Sodiaal-Candia, La Talaudière, France) were prepared from the same milk batch therefore only differing by their additives.…”

“…Imaging experiments were performed on the Cell Station of CellImaP platform (IFR100, Dijon, France). Paraffin sections were rehydrated and prepared as previously described (Milard et al, 2018). To count the number of goblet cells, sections were stained with Alcian blue and periodic acid-Schiff's reagent to visualize the total mucins.…”

“…The intestinal epithelium (duodenum, jejunum, and ileum) was analyzed by assessing the number of goblet cells per crypt-villus axis. Livers were stained with hematoxylin and eosin and were examined to determine liver damage score as previously described (Milard et al, 2018).…”