Chemical and Proteolysis-Derived Changes during Long-Term Storage of Lactose-Hydrolyzed Ultrahigh-Temperature (UHT) Milk

Jansson, Therese; Jensen, Hanne Bak; Sundekilde, Ulrik Kræmer; Clausen, Morten Rahr; Eggers, Nina; Larsen, Lotte Bach; Ray, Colin; Bertram, Hanne Christine

doi:10.1021/jf504104q

Cited by 47 publications

(40 citation statements)

References 31 publications

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“…Limited proteolysis by proteases present in the milk or originating from the lactase preparation may enhance the reaction. This results in the increased formation of off-flavors, in the browning of lactose-free milk when compared to regular milk and in a reduced nutritional value when stored at increased temperatures [10,17,18]. The increased Maillard reaction is probably the most important determinant of the reduced shelf life of lactose-free UHT milk compared to regular UHT milk.…”

Section: Production Of Lactose-free Dairymentioning

confidence: 99%

Lactose-Free Dairy Products: Market Developments, Production, Nutrition and Health Benefits

Dekker

Koenders

Bruins³

2019

Nutrients

162

109

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Lactose-free dairy is able to provide the essential nutrients present in regular dairy products, like calcium and vitamins, to those that are not able to digest lactose. This product category currently has a wide and growing health appeal to consumers. In recent years, the quality and product variety in the lactose-free dairy segment has been increasing significantly, giving consumers more tempting products to decide from. As a result, lactose-free dairy is now the fastest growing market in the dairy industry. This review discusses the market developments and production possibilities and issues related to the wide variation of lactose-free dairy products that are currently available. Additionally, the health benefits that lactose-free dairy may offer compared to dairy avoidance are illustrated.

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Section: Production Of Lactose-free Dairymentioning

confidence: 99%

Lactose-Free Dairy Products: Market Developments, Production, Nutrition and Health Benefits

Dekker

Koenders

Bruins³

2019

Nutrients

162

109

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“…In recent years, physical and chemical changes that might reduce the shelf‐life of UHT milk have been widely studied, mainly focusing on milk protein sedimentation and age gelation (Malmgren et al., ), browning and off‐flavor from the Maillard reaction (Sunds, Rauh, Sørensen, & Larsen, ), and proteolysis‐derived changes (Jansson et al., ; Pinto, de, Machado, Cardoso, & Vanetti, ). However, the physical and chemical properties of fat, an important fraction, in stored UHT milk have been less well studied.…”

Section: Introductionmentioning

confidence: 99%

Lipolysis and Oxidation in Ultra‐High Temperature Milk Depend on Sampling Month, Storage Duration, and Temperature

Jing

Langton

Sampels

et al. 2019

Journal of Food Science

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During storage, some factors (for example, storage duration and temperature) can affect milk stability and consumer acceptability. Thiobarbituric acid reactive substances (TBARSs), lipid classes, and fatty acid profiles in stored ultra-high temperature (UHT) milk were analyzed to assess the effects of storage time and temperature on lipid oxidation and lipolysis. With storage duration up to 12 months, the milk fat phase was separated and showed high levels of oxidation and lipolysis, manifested as increased levels of TBARS and free fatty acids. High oxidation levels decreased the percentage of unsaturated fatty acids (UFAs) in triacylglycerol and phospholipids. Higher storage temperatures (20, 30, and 37°C) resulted in a higher degree of fat aggregation, oxidation, and lipolysis compared with refrigerated storage (4°C). Additionally, sampling month of raw milk (May, July, and November) affected the lipid profiles of UHT milk during storage, with more UFA oxidized in July than in the other 2 months.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Food ChemistryLipid oxidation and lipolysis in stored UHT milk . . . separated off and subsamples were used for analysis (for details of the experimental design, see Figure A.1 in the Supplementary Material). Confocal laser scanning microscopy analysisThe samples were prepared as previously described (Lu et al., 2018), by mixing 0.5 mL of UHT milk with 5 µL of Nile Red stock solution (0.1% Nile Red in acetone, Sigma-Aldrich, St Louis, MO, USA) for 15 min at room temperature. The final mixture (20 µL) was placed on a concave microscope slide for confocal laser scanning microscopy. A Zeiss LSM 780 confocal laser scanning microscope (Jena, Germany) was used for microstructure analysis. A 488 nm Argon laser was used as excitation source and the fluorescence emissions of wavelengths between 500 and 530 nm were detected. Images were acquired using a C-Apochromat 63× oil immersion objective (NA 1.32) with a resolution of 1,024 × 1,024 pixels.

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“…The Maillard reaction or so-called “glycation”, a chemical reaction between free amino compounds (e.g., proteins) and carbonyl compounds (e.g., reducing sugars), causes significant changes in the physical and nutritional properties of food. Proteolysis of a protein induced by residual proteases in LH milk can thus generate additional free amino terminals (α-NH 2 ) in polypeptides, smaller peptides, or even free amino acids, which may react with glucose and galactose during storage [7,8,9,10,11]. In addition, glucose and galactose, being the hydrolysis products of lactose, are more reactive than lactose in glycation.…”

Section: Introductionmentioning

confidence: 99%

Interplay between Residual Protease Activity in Commercial Lactases and the Subsequent Digestibility of β-Casein in a Model System

Zhao

Larsen

et al. 2019

Molecules

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One of the conventional ways to produce lactose-hydrolyzed (LH) milk is via the addition of commercial lactases into heat-treated milk in which lactose is hydrolyzed throughout storage. This post-hydrolysis method can induce proteolysis in milk proteins due to protease impurities remaining in commercial lactase preparations. In this work, the interplay between lactose hydrolysis, proteolysis, and glycation was studied in a model system of purified β-casein (β-CN), lactose, and lactases using peptidomic methods. With a lactase presence, the proteolysis of β-CN was found to be increased during storage. The protease side-activities mainly acted on the hydrophobic C-terminus of β-CN at Ala, Pro, Ile, Phe, Leu, Lys, Gln, and Tyr positions, resulting in the formation of peptides, some of which were N-terminal glycated or potentially bitter. The proteolysis in β-CN incubated with a lactase was shown to act as a kind of “pre-digestion”, thus increasing the subsequent in vitro digestibility of β-CN and drastically changing the peptide profiles of the in vitro digests. This model study provides a better understanding of how the residual proteases in commercial lactase preparations affect the quality and nutritional aspects of β-CN itself and could be related to its behavior in LH milk.

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Chemical and Proteolysis-Derived Changes during Long-Term Storage of Lactose-Hydrolyzed Ultrahigh-Temperature (UHT) Milk

Cited by 47 publications

References 31 publications

Lactose-Free Dairy Products: Market Developments, Production, Nutrition and Health Benefits

Lactose-Free Dairy Products: Market Developments, Production, Nutrition and Health Benefits

Lipolysis and Oxidation in Ultra‐High Temperature Milk Depend on Sampling Month, Storage Duration, and Temperature

Interplay between Residual Protease Activity in Commercial Lactases and the Subsequent Digestibility of β-Casein in a Model System

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