Browsing by Author "Thum C"

Now showing 1 - 6 of 6
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    Concentration of milk oxylipins after heat and homogenization treatments
    (Frontiers Media S A, 2023-05-26) Thum C; Cirelli A; Otoki Y; Ozturk G; Taha AY; McNabb WC; Roy NC; de Moura Bell JMLN; Hebishy E
    Heat treatment and homogenization of milk are common processing steps intended to reduce microbial load for safe human consumption, and to avoid creaming, respectively. Although the effects of combined pasteurization and homogenization on free fatty acids (FFA) and lipid oxidation markers such as hydroperoxides, and thiobarbituric acid reactive species (TBARS) have been well characterized, their effects on primary oxidized fatty acids known as oxylipins have not yet been determined. This study aimed to determine the effects of two heat treatments: milk pasteurization [high-temperature short time, 72°C for 15 s (HTST)] and sterilization [ultra-high temperature, 135°C for 3 s (UHT)] with or without homogenization (10, 17 or 24 MPa) on FFA (%), primary (hydroperoxides and oxylipins) and secondary oxidation compounds (TBARS). Heat treatments alone significantly reduced most oxylipins compared with raw milk, but did not alter % FFA, hydroperoxide, and TBARS levels. The combination of UHT and homogenization at 24 MPa increased % FFA, hydroperoxide value, and some oxylipins, compared to raw milk and other treatments. Overall, the combination of heat treatment and homogenization significantly increased oxylipin formation compared with heat treatment alone.
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    Functional Significance of Probiotic Bacterial Interactions with Milk Fat Globules in a Human Host
    (MDPI (Basel, Switzerland), 2025-02) Wasana WP; Waterland M; Everett DW; Thum C; Comi G
    Dairy products often serve as matrices for delivering probiotic bacteria to humans through the diet; however, little is known about the impact of milk fat globules on the growth and survival of probiotic microorganisms. This review discusses current knowledge on the structure and functionality of the milk fat globule membrane (MFGM) and the structural components contributing to the mechanisms of interactions with probiotic bacteria. We analyzed studies published between 2001 and 2025 with reference to earlier foundational research on probiotics and MFGM structure to explore the functional significance of MFGM–probiotic interactions. Recent research indicates that the effects of MFGM interaction with bacteria are species-specific and may influence probiotic activity in the host, including enhancing probiotic viability during intestinal transit and modulating probiotic colonization. In general, research findings suggest that the MFGM holds potential for use as a probiotic carrier to the gut with beneficial health consequences.
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    In vitro Fermentation of Digested Milk Fat Globule Membrane From Ruminant Milk Modulates Piglet Ileal and Caecal Microbiota
    (Frontiers Media S.A., 2020-07-09) Thum C; Young W; Montoya CA; Roy NC; McNabb WC; Benítez-Páez A
    Lipids in milk are secreted as a triacylglycerol core surrounded by a trilayer membrane, the milk fat globule membrane (MFGM). This membrane, known to have important roles in infant brain and intestinal development, is composed of proteins, glycoproteins, and complex lipids. We hypothesized that some of the beneficial properties of MFGM are due to its effects on the gastrointestinal microbiota. This study aimed to determine the effect of a commercial phospholipid concentrate (PC) and enriched bovine, caprine, and ovine MFGM fractions on ileal and hindgut microbiota in vitro. Digestion of PC and MFGMs was conducted using an in vitro model based on infant gastric and small intestine conditions. The recovered material was then in vitro fermented with ileal and caecal inocula prepared from five piglets fed a commercial formula for 20 days before ileal and caecal digesta were collected. After each fermentation, samples were collected to determine organic acid production and microbiota composition using 16S rRNA sequencing. All substrates, except PC (5%), were primarily fermented by the ileal microbiota (8-14%) (P < 0.05). PC and caprine MFGM reduced ileal microbiota alpha diversity compared to ileal inoculum. Caprine MFGM increased and PC reduced the ileal ratio of firmicutes:proteobacteria (P < 0.05), respectively, compared to the ileal inoculum. Bovine and ovine MFGMs increased ileal production of acetic, butyric, and caproic acids compared to other substrates and reduced the proportions of ileal proteobacteria (P < 0.0001). There was a limited fermentation of bovine (3%), caprine (2%), and ovine (2%) MFGMs by the caecal microbiota compared to PC (14%). In general, PC and all MFGMs had a reduced effect on caecal microbiota at a phylum level although MFG source-specific effects were observed at the genus level. These indicate that the main effects of the MFGM in the intestinal microbial population appears to occur in the ileum.
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    Understanding the Effects of Lactose Hydrolysis Modeling on the Main Oligosaccharides in Goat Milk Whey Permeate
    (MDPI (Basel, Switzerland), 2019-09-10) Thum C; Weinborn V; Barile D; McNabb WC; Roy NC; Leite Nobrega de Moura Bell JM; Moreno DA; Villaño D
    Enzymatic hydrolysis of lactose is a crucial step to improve the efficiency and selectivity of membrane-based separations toward the recovery of milk oligosaccharides free from simple sugars. Response surface methodology was used to investigate the effects temperature (25.9 to 54.1 °C) and amount of enzyme (0.17 to 0.32% w/w) at 1, 2, and 4 h of reaction on the efficiency of lactose hydrolysis by Aspergillus oryzae β-galactosidase, preservation of major goat whey oligosaccharides, and on the de-novo formation of oligosaccharides. Lactose hydrolysis above 99% was achieved at 1, 2, and 4 h, not being significantly affected by temperature and amount of enzyme within the tested conditions. Formation of 4 Hexose (Hex) and 4 Hex 1 Hex and an increased de-novo formation of 2 Hex 1 N-Acetyl-Neuraminic Acid (NeuAc) and 2 Hex 1 N-Glycolylneuraminic acid (NeuGc) was observed in all treatments. Overall, processing conditions using temperatures ≤40 °C and enzyme concentration ≤0.25% resulted in higher preservation/formation of goat whey oligosaccharides.
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    Variation in milk fat globule size and composition: A source of bioactives for human health
    (Taylor and Francis Group, 2023) Thum C; Roy NC; Everett DW; McNabb WC
    Milk fat globules (MFGs) are secreted from the mammalian gland and are composed of a triacylglycerol core surrounded by a triple membrane structure, the milk fat globule membrane (MFGM). The MFGM contains complex lipids and proteins reported to have nutritional, immunological, neurological and digestive functions. Human and ruminant milk are shown to share a similar MFG structure but with different size, profile and abundance of protein and polar lipids. This review summarizes the reported data on human, bovine, caprine and ovine MFG composition and concentration of bioactive components in different MFG-size fractions. A comprehensive understanding of compositional variations between milk from different species and MFG size fractions may help promote various milk sources as targeted supplements to improve human development and health. MFG size and MFGM composition are species-specific and affected by lactation, diet and breed (or maternal origin). Purification and enrichment methods for some bioactive proteins and lipids present in the MFGM have yet to be established or are not scaled sufficiently to be used to supplement human diets. To overcome this problem, MFG size selection through fractionation or herd selection may provide a convenient way to pre-enrich the MFG fraction with specific protein and lipid components to fulfill human dietary and health requirements.