scholarly journals Influence of Ultra-Heat Treatment on Properties of Milk Proteins

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3164
Author(s):  
Thummalacharla Chaitanya Krishna ◽  
Agnieszka Najda ◽  
Aarti Bains ◽  
Mansuri M. Tosif ◽  
Rafał Papliński ◽  
...  
Keyword(s):  
Milk Proteins ◽  
Storage Condition ◽  
Processing Parameters ◽  
Protein Isolate ◽  
Heat Treatments ◽  
Major Protein ◽  
Uht Milk ◽  
Sediment Formation ◽  
Processing And Storage ◽  
Subsequent Storage

Milk can be considered one of the primary sources of nutrients for the mammalian neonate. Therefore, milk and milk-based products, such as infant formula, whey protein isolate, different varieties of cheese, and others are prepared to meet the nutritional requirements of the consumer. Due to its significant nutritional components and perishable nature, a variety of pathogenic microorganisms can grow and multiply quickly in milk. Therefore, various heat treatments can be employed for the improvement of the shelf life of milk. In comparison to pasteurized milk, due to excessive and severe heating, UHT milk has a more cooked flavor. During storage, changes in the physicochemical properties of milk can lead to off-flavors, undesirable browning, separation of fat, sediment formation, or gelation during the subsequent storage. Several important factors such as processing parameters, time-temperature abuse (storage condition), and packaging type also influence the quality characteristics and consumer acceptance of the milk; however, the influence of heat treatments on milk protein is inconstant. The major protein modifications that occur during UHT treatment are denaturation and aggregation of the protein, and chemical modifications of its amino acids. These UHT-induced protein alterations can change digestibility and the overall biological influence of the intake of these proteins. Therefore, this review is focused on the influence of UHT on the physicochemical and structural attributes of milk proteins during storage. There are many indications of milk proteins present in the UHT milk, and milk products are altered during processing and storage.

Contribution of casein micelle size and proteolysis on protein distribution and sediment formation in UHT milk during storage

2021 ◽  
Vol 117 ◽  
pp. 104980
Author(s):  
Marije Akkerman ◽  
Lene Buhelt Johansen ◽  
Valentin Rauh ◽  
Nina Aagaard Poulsen ◽  
Lotte Bach Larsen
Keyword(s):  
Casein Micelle ◽  
Protein Distribution ◽  
Uht Milk ◽  
Micelle Size ◽  
Sediment Formation

Functional Properties of the Protein Isolate and Major Fractions of Pine Nut Proteins Prepared from the Changbai Mountain in China

2014 ◽  
Vol 881-883 ◽  
pp. 766-775 ◽  
Author(s):  
Dan Wu ◽  
Wei Hong Min ◽  
Jing Sheng Liu ◽  
Li Fang ◽  
Hong Mei Li ◽  
...  
Keyword(s):  
Amino Acids ◽  
Functional Properties ◽  
Protein Solubility ◽  
Essential Amino Acids ◽  
Protein Isolate ◽  
Absorption Capacity ◽  
Changbai Mountain ◽  
Major Protein ◽  
Pine Nut ◽  
A Value

The functional properties of protein isolate and major protein fractions prepared from Changbai Mountain pine nuts were investigated. Albumin, globulin, glutelin, and protein isolates were obtained after the Osborne method and alkaline dissolution and acid precipitation, and protein contents of the fractions are 48.02%, 81.93%, 83.02%, and 89.69%, respectively. For the sulfhydryl contents, albumin is the highest, and glutelin is the lowest. In a disulphide bond, the protein isolate content is the highest with a value of 28.74 μmol/g, and the glutelin content is the lowest with the value of 13.46 μmol/g. For the four kinds of proteins, the essential amino acids in percentage of total amino acids are 31.13%, 34.22%, 30.30%, and 34.54%, respectively. The pH dependent protein solubility profile reveals that the minimum solubility is at pH 5.0, which corresponds to the isoelectric point. Protein isolate has the minimum water absorption capacity with a value of 0.59 ml/g. On the other hand, albumin has the minimum oil absorption capacity with a value of 2.11 ml/g. The emulsifying activity and stability and the foaming activity and stability increased with increasing concentration of four kinds of proteins. SDS-PAGE results showed that these four kinds of proteins have different molecules.

scholarly journals Dynamics of Microbial Inactivation and Acrylamide Production in High-Temperature Heat Treatments

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2535
Author(s):  
Jose Lucas Peñalver-Soto ◽  
Alberto Garre ◽  
Arantxa Aznar ◽  
Pablo S. Fernández ◽  
Jose A. Egea
Keyword(s):  
High Temperature ◽  
Food Safety ◽  
High Temperatures ◽  
Processing Parameters ◽  
Temperature Treatment ◽  
Heat Treatments ◽  
Microbial Inactivation ◽  
Point Of View ◽  
High Temperature Treatment ◽  
Microbiological Safety

In food processes, optimizing processing parameters is crucial to ensure food safety, maximize food quality, and minimize the formation of potentially toxigenic compounds. This research focuses on the simultaneous impacts that severe heat treatments applied to food may have on the formation of harmful chemicals and on microbiological safety. The case studies analysed consider the appearance/synthesis of acrylamide after a sterilization heat treatment for two different foods: pureed potato and prune juice, using Geobacillus stearothermophilus as an indicator. It presents two contradictory situations: on the one hand, the application of a high-temperature treatment to a low acid food with G. stearothermophilus spores causes their inactivation, reaching food safety and stability from a microbiological point of view. On the other hand, high temperatures favour the appearance of acrylamide. In this way, the two objectives (microbiological safety and acrylamide production) are opposed. In this work, we analyse the effects of high-temperature thermal treatments (isothermal conditions between 120 and 135 °C) in food from two perspectives: microbiological safety/stability and acrylamide production. After analysing both objectives simultaneously, it is concluded that, contrary to what is expected, heat treatments at higher temperatures result in lower acrylamide production for the same level of microbial inactivation. This is due to the different dynamics and sensitivities of the processes at high temperatures. These results, as well as the presented methodology, can be a basis of analysis for decision makers to design heat treatments that ensure food safety while minimizing the amount of acrylamide (or other harmful substances) produced.

Mechanical Behaviour of Gas Nitrided Ti6Al4V Bars Produced by Selective Laser Melting

2016 ◽  
Vol 704 ◽  
pp. 225-234 ◽  
Author(s):  
Peter Franz ◽  
Aamir Mukhtar ◽  
Warwick Downing ◽  
Graeme Smith ◽  
Ben Jackson
Keyword(s):  
Heat Treatment ◽  
Selective Laser Melting ◽  
Nitrided Layer ◽  
Xrd Analysis ◽  
Compound Layer ◽  
Processing Parameters ◽  
Heat Treatments ◽  
Laser Melting ◽  
Gas Nitriding ◽  
Heat Treated

Gas atomized Ti-6Al-4V (Ti64) alloy powder was used to prepare distinct designed geometries with different properties by selective laser melting (SLM). Several heat treatments were investigated to find suitable processing parameters to strengthen (specially to harden) these parts for different applications. The results showed significant differences between tabulated results for heat treated billet Ti64 and SLM produced Ti64 parts, while certain mechanical properties of SLM Ti64 parts could be improved by different heat treatments using different processing parameters. Most heat treatments performed followed the trends of a reduction in tensile strength while improving ductility compared with untreated SLM Ti64 parts.Gas nitriding [GN] (diffusion-based thermo-chemical treatment) has been combined with a selected heat treatment for interstitial hardening. Heat treatment was performed below β-transus temperature using minimum flow of nitrogen gas with a controlled low pressure. The surface of the SLM produced Ti64 parts after gas nitriding showed TiN and Ti2N phases (“compound layer”, XRD analysis) and α (N) – Ti diffusion zones as well as high values of micro-hardness as compared to untreated SLM produced Ti64 parts. The microhardness profiles on cross section of the gas nitrided SLM produced samples gave information about the i) microhardness behaviour of the material, and ii) thickness of the nitrided layer, which was investigated using energy dispersive spectroscopy (EDS) and x-ray elemental analysis. Tensile properties of the gas nitrided Ti64 bars produced by SLM under different conditions were also reported.

scholarly journals Preparation and Characterization of Whey Protein-Based Polymers Produced from Residual Dairy Streams

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 722 ◽  
Author(s):  
Chalermthai ◽  
Chan ◽  
Bastidas-Oyanedel ◽  
Taher ◽  
Olsen ◽  
...  
Keyword(s):  
Whey Protein ◽  
Protein Concentration ◽  
Milk Proteins ◽  
Protein Isolate ◽  
Whey Protein Concentrate ◽  
Polymer Sheets ◽  
Lower Protein ◽  
Poly Ethylene ◽  
The One

The wide use of non-biodegradable, petroleum-based plastics raises important environmental concerns, which urges finding alternatives. In this study, an alternative way to produce polymers from a renewable source—milk proteins—was investigated with the aim of replacing polyethylene. Whey protein can be obtained from whey residual, which is a by-product in the cheese-making process. Two different sources of whey protein were tested: Whey protein isolate (WPI) containing 91% protein concentration and whey protein concentrate (WPC) containing 77% protein concentration. These were methacrylated, followed by free radical polymerization with co-polymer poly(ethylene glycol) methyl ether methacrylate (PEGMA) to obtain polymer sheets. Different protein concentrations in water (11–14 w/v%), at two protein/PEGMA mass-ratios, 20:80 and 30:70, were tested. The polymers made from WPI and WPC at a higher protein/PEGMA ratio of 30:70 had significantly better tensile strength than the one with lower protein content, by about 1–2 MPa (the best 30:70 sample exhibited 3.8 ± 0.2 MPa and the best 20:80 sample exhibited 1.9 ± 0.4 MPa). This indicates that the ratio between the hard (protein) and soft (copolymer PEGMA) domains induce significant changes to the tensile strengths of the polymer sheets. Thermally, the WPI-based polymer samples are stable up to 277.8 ± 6.2 °C and the WPC-based samples are stable up to 273.0 ± 3.4 °C.

Evaluation of an enzymatically treated soya protein in the diet of weaned pigs

1994 ◽  
Vol 1994 ◽  
pp. 160-160
Author(s):  
C A Weeks ◽  
BG Miller ◽  
L Green ◽  
S Rizvi ◽  
C Beck ◽  
...  
Keyword(s):  
Milk Proteins ◽  
Protein Isolate ◽  
Soya Protein ◽  
Test Diet ◽  
Soya Protein Isolate ◽  
Commercial Farms ◽  
Main Protein ◽  
Soya Proteins ◽  
Set Up ◽  
Experimental Pigs

Soya proteins can provoke an immune response and cause diarrhoea in pigs weaned at 3 weeks of age. An enzymatically treated soya protein isolate (NURISH protein) did not have these effects in isolator reared experimental pigs (Miller et al 1992). A blind trial on 4 commercial farms was set up to evaluate NURISH as an alternative to conventional protein sources.On each farm 120 pigs (in 2 or 3 replicates) were fed either a typical commercial weaner diet containing cereals, fishmeal, milk proteins and full fat soya (the control) or a test diet matched for protein (22% CP), lysine (1.6%) and energy (DE 15.1 MJ/kg) with NURISH as the main protein source. Prophylactic antibiotics were not used.

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