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When casein is replaced with starch in imitation cheese, the functionality changes. Three different microscopy methods were applied to understand the microstructural differences in the product depending on which component dominates the microstructure. Confocal Laser Scanning Microscopy (CLSM) for component identification. Scanning Electron Microscopy (SEM) and Cryogenic Scanning Electron Microscopy (Cryo-SEM) for studying surface structures. Differences in the surface structures were detected between SEM and Cryo-SEM. In SEM, starch appeared rough and protein smooth, while in Cryo-SEM no starch roughness of the surface was found. A change in starch modification and effects of protein prehydration was also analysed. Adding octenyl succinic anhydride (OSA) modified starch for emulsifying properties resulted in a microstructure with fragmented protein at a protein level of 7 %, but not at 9 or 12 %. Protein prehydration had limited effect on microstructure. On a macrostructural level, the change to an emulsifying starch increased hardness in imitation cheese with 7 and 9 % protein. Protein prehydration slightly decreased the hardness, but the difference was not significant at all concentrations. This research provides valuable information about the microstructure of imitation cheese at a 50/50 composition, how the microstructure changes with an emulsifying starch and what occurs after a protein prehydration was included in the production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Reduction of sodium chloride (NaCl) in cheese manufacturing is a challenge for the dairy industry. NaCl has a profound role on microbial development influencing cheese sensory and technological properties. The purpose of this work was to investigate how proliferation, distribution and autolysis of two commercial DL-starter cultures (C1 and C2) used in the production of Danish semi-hard Samsoe cheeses were affected by reduced NaCl levels. Cheeses containing <0.3% (unsalted), 2.3% (reduced-salt) and 3.4% (normal-salted) (w/v) NaCl in moisture were produced and analyzed during 12 weeks of ripening. Lactic acid bacteria (LAB), distribution of bacteria as single cells or microcolonies, their viability in the cheeses and cell autolysis were monitored during ripening, as well as the impact of NaCl content and autolysis on the formation of free amino acids (FAA). Reduction of NaCl resulted in higher LAB counts at the early stages of ripening, with differences between the two DL-starter cultures. The unsalted cheeses produced with C1 had retained a significantly higher number of the initial LAB counts (cfu/g) after 1 and 2 weeks of ripening (i.e. 58% and 71%), compared to the normal-salted cheeses (i.e. 22% and 21%), whereas no significant difference was found between the reduced-salt (i.e. 31% and 35%) and normal-salted cheeses. At the later stages of ripening (i.e. 7 and 11 weeks) NaCl had no significant influence. For cheeses produced with C2, a significant influence of NaCl was only found in cheeses ripened for 7 weeks, where the unsalted and reduced-salt cheeses had retained a significantly higher number of the initial LAB counts (cfu/g) (i.e. 39% and 38%), compared to the normal-salted cheeses (i.e. 21%). In the Samsoe cheeses, bacteria were organized as single cells, in groups of 2-3 cells or in groups of ≥4 cells. During ripening the decrease in the number of viable bacteria was mainly due to a reduction in the number of viable bacteria organized in groups of ≥4 cells. A negative correlation between NaCl content and PepX activity was observed. At the end of ripening the total FAA content was lower in the unsalted cheeses, compared to the reduced- and normal-salted cheeses. In conclusion, NaCl had a significant influence on proliferation of both DL-starter cultures. However, the influence of NaCl on culture development was more pronounced in cheeses produced with DL-starter culture C1. As both texture and taste are parameters known to be affected by the development of the starter culture, the design of starter cultures for reduced NaCl cheeses is recommended., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The effect of two different antioxidants, EDTA and green tea extract (GTE), used individually or in combination, on the light-induced oxidation of reduced fat soft cheeses (0.2 and 6% fat) was investigated. In samples with 0.2% fat, lipid hydroperoxides as primary lipid oxidation products were not detected, but their interference was suggested from the formation of secondary lipid oxidation products such as hexanal and heptanal. The occurrence of these oxidation markers was inhibited by spiking with 50 ppm EDTA or 750 ppm GTE, or a combination of the two prior to irradiation. In contrast, addition of 50 ppm EDTA to samples with 6% fat was ineffective, but 750 ppm GTE (alone or in combination with EDTA) strongly reduced levels of hexanal and heptanal. Accumulation of primary lipid hydroperoxides was not affected by GTE, hence antioxidative activity was ascribed to scavenging of hexanal and heptanal precursors. These radical intermediates result from hydroperoxide disintegration, and subsequent scavenging by GTE, which acts as a radical sink, corroborates the intense signal observed by electron paramagnetic resonance (EPR) spectroscopy.

Background The dairy matrix may influence digestion and absorption of lipids and thereby risk of cardiovascular diseases (CVDs). However, few postprandial studies have compared dairy products that differed only in terms of their matrix. Objectives We aimed to investigate acute 8-h postprandial lipid, glycemic, and appetite responses after intake of isoenergetic dairy meals with different matrixes, but similar nutritional composition. Methods Twenty-five normal-weight men (18–40 y old) were enrolled in a randomized controlled crossover trial. On 4 test days, a meal with 1 of 4 dairy products was served: cheddar cheese (Cheese), homogenized Cheese (Hom. Cheese), micellar casein isolate (MCI) with cream (MCI Drink), and a gel produced from the MCI Drink by addition of Glucono Delta-Lactone (MCI Gel). The fat- and protein-matched dairy products differed in terms of their casein network, fat droplet size, and/or texture. Blood biochemistry and appetite responses were collected. Results Eighteen participants completed the trial. Postprandial triglycerides (TGs) (primary outcome) increased by (mean ± SEM) 0.24 ± 0.07 and 0.19 ± 0.07 mmol/L after MCI Gel compared with Cheese and Hom. Cheese, respectively (both P  ≤ 0.05). Likewise, MCI Gel increased TG incremental AUC compared with Cheese and Hom. Cheese (both P <  0.05), and peak compared with Cheese (P  < 0.05). ApoB-48 (primary outcome) was unaffected by dairy matrix. For free fatty acids (FFAs), glucose, and insulin, time × meal interactions were observed (all P  < 0.001). During the first 2 h, FFAs were lower for Cheese than for MCI products, whereas the opposite was observed for glucose and insulin. Conclusions Postprandial TG but not apoB-48 response was higher after MCI Gel, indicating that the type of casein network influences lipid responses. This suggests that the dairy matrix may also affect risk factors for CVDs. Reducing fat droplet size (i.e. Hom. Cheese) did not affect blood biochemistry. This trial was registered at clinicaltrials.gov as NCT03656367. [ABSTRACT FROM AUTHOR]

The paper describes a study on the variation of coagulation properties in individual cow's milk measured by a novel free oscillation rheometry-based method. The work is part of a study on the occurrence and underlying causes of poorly and even non-coagulating (NC) milk in Denmark, and based on that, the paper reports on the frequency of non- and poorly coagulating milk in a herd of the three main Danish dairy breeds, Jersey, Danish red (RDM), and Danish Holstein-Friesian (SDM). The cows were milked by automatic milking. The rennet coagulation time, the coagulum firmness by storage modulus G′, and the curd firming rate of fresh skimmed milk were determined. More than 20% of the milk samples exhibited poor coagulation properties by the criteria set. Of these, the 17% resulted in a weak coagulum after addition of rennet, while another 3% were due to NC milk that did not aggregate to form a curd within the 40 min of measurement. Milk from Jersey cows exhibited superior coagulation properties when compared to milk from SDM and RDM cows. The dependence of curd firming rate on protein concentration was investigated, and found to depend on milk protein concentration to the power of three, emphasizing the importance of protein interactions, and not just the protein concentration itself. The paper gives a basis for the subsequent selection of NC milk samples with the aim to look in more detail for the underlying reasons for the phenomenon of NC milk. [ABSTRACT FROM AUTHOR]

This study investigated the postprandial plasma metabolome following consumption of four dairy matrices different in texture and structure: cheddar cheese (Cheese), homogenized cheddar cheese (Hom. Cheese), and micellar casein isolate (MCI) with cream (MCI Drink) or a MCI Gel. An acute, randomized, crossover trial in male participants (n = 25) with four test days was conducted. Blood samples were collected during an 8-h postprandial period after consumption of a meal similar in micro- and macronutrients containing one of the four dairy matrices, and the metabolome was analyzed using nuclear magnetic resonance (NMR) spectroscopy. A liquid dairy matrix (MCI Drink) resulted in a faster absorption of amino acids compared to products, representing either a semi-solid (MCI Gel and Hom. Cheese) or solid (Cheese) dairy matrix. For the MCI Gel, plasma concentration of acetic acid and formic acid increased approximately 2 h following consumption, while 3-hydroxybyturate and acetoacetic acid increased approximately 6 h after consumption. The structure and texture of the dairy matrix affected the postprandial absorption of amino acids, as revealed by the plasma metabolome. Our study furthermore pointed at endogenous effects associated with consumption of dairy products containing glucono-δ-lactone. [ABSTRACT FROM AUTHOR]

Studies have indicated that the dairy matrix can affect postprandial responses of dairy products, but little is known about the effect on postprandial plasma phospholipid levels. This study investigated postprandial plasma phospholipid levels following consumption of four different dairy products that are similar in micro and macro nutrients, but different in texture and structure: cheddar cheese (Cheese), homogenized cheddar cheese (Hom. Cheese), micellar casein isolate with cream (MCI Drink) or a gel made from the MCI Drink (MCI Gel). The study was an acute randomized, crossover trial in human volunteers with four test days. Blood samples were collected during an 8 h postprandial period and the content of 53 plasma phospholipids was analysed using liquid chromatography-mass spectrometry (LC-MS). No meal–time interactions were revealed; however, for nine of the 53 phospholipids, a meal effect was found. Thus, the results indicated a lower plasma level of specific lyso-phosphatidylethanolamines (LPEs) and lyso-phosphatidylcholines (LPCs) following consumption of the MCI Gel compared to the MCI Drink and Hom. Cheese, which might be attributed to an effect of viscosity. However, further studies are needed in order to reveal more details on the effect of the dairy matrix on postprandial phospholipids. [ABSTRACT FROM AUTHOR]