Influence of partially demineralized milk proteins on rheological properties and microstructure of acid gels

Innovative clean label processes employed in the manufacture of acid gels are targeted to modify the structure of proteins that contribute to rheological properties. In the present study, CO₂-treated milk protein concentrate powder with 80% protein in dry matter (TMPC80) was mixed with nonfat dry milk (NDM) in different ratios for the manufacture of acid gels. Dispersions of NDM and TMPC80 that provided 100, 90, 70, and 40% of protein from NDM were reconstituted to 4.0% (wt/wt) protein and 12.0% (wt/wt) total solids. Dispersions were adjusted to pH 6.5, followed by heat treatment at 90°C for 10 min. Glucono-δ-lactone was added and samples were incubated at 30°C, reaching pH 4.5 ± 0.05 after 4 h of incubation. Glucono-δ-lactone levels were adjusted to compensate for the lower buffering capacity of samples with higher proportions of TMPC80, which is attributable to the depletion of buffering minerals from both the serum and micellar phase during preparation of TMPC80. Sodium dodecyl sulfate-PAGE analysis indicated a higher amount of caseins in the supernatant of unheated suspensions with increasing proportions of CO₂-treated TMPC80, attributable to the partial disruption of casein micelles in TMPC80. Heat treatment reduced the level of whey proteins in the supernatant due to the heat-induced association of whey proteins with casein micelles, the extent of which was larger in samples containing more micellar casein (i.e., samples with a lower proportion of TMPC80). Particle size analysis showed only small differences between nonheated and heated dispersions. Gelation pH increased from ?5.1 to ?5.3, and the storage modulus of the gels at pH 4.5 increased from ?300 to ?420 Pa when the proportion of protein contributed by TMPC80 increased from 0 to 60%. Water-holding capacity also increased and gel porosity decreased with increasing proportion of protein contributed by TMPC80. The observed gel properties were in line with microstructural observations by confocal microscopy, wherein sample gels containing increasing levels of TMPC80 exhibited smaller, well-connected aggregates with uniform, homogeneous pore sizes. We concluded that TMPC80 can be used to partially replace NDM as a protein source to improve rheological and water-holding properties in acid gels. The resultant gels also exhibited decreased buffering, which can improve the productive capacity of yogurt manufacturing plants. Overall, the process can be leveraged to reduce the amount of hydrocolloids added to improve yogurt consistency and water-holding capacity, thus providing a path to meet consumer expectations of clean label products.     

Genome-wide association study for αS1- and αS2-casein phosphorylation in Dutch Holstein Friesian

Phosphorylation of caseins (CN) is a crucial post-translational modification that allows caseins to form colloid particles known as casein micelles. Both α_S1- and α_S2-CN show varying degrees of phosphorylation (isoforms) in cow milk and were suggested to be more relevant for stabilizing internal micellar structure than β- and κ-CN. However, little is known about the genetic background of individual α_S2-CN phosphorylation isoforms and the phosphorylation degrees of α_S1- and α_S2-CN (α_S1-CN PD and α_S2-CN PD), defined as the proportion of isoforms with higher degrees of phosphorylation in total α_S1- and α_S2-CN, respectively. We aimed to identify genomic regions associated with these traits using 50K single nucleotide polymorphisms for 1,857 Dutch Holstein Friesian cows. A total of 10 quantitative trait loci (QTL) regions were identified for all studied traits on 10 Bos taurus autosomes (BTA1, 2, 6, 9, 11, 14, 15, 18, 24, and 28). Regions associated with multiple traits were found on BTA1, 6, 11, and 14. We showed 2 QTL regions on BTA1, one affecting α_S2-CN production and the other harboring the SLC37A1 gene, which encodes a phosphorus antiporter and affects α_S1- and α_S2-CN PD. The QTL on BTA6 harbors the casein gene cluster and affects individual α_S2-CN phosphorylation isoforms. The QTL on BTA11 harbors the PAEP gene that encodes for β-lactoglobulin and affects relative concentrations of α_S2-CN-10P and α_S2-CN-11P as well as α_S1-CN PD and α_S2-CN PD. The QTL on BTA14 harbors the DGAT1 gene and affects relative concentrations of α_S2-CN-10P and α_S2-CN-11P as well as α_S1-CN PD and α_S2-CN PD. Our results suggest that effects of identified genomic regions on phosphorylation of α_S1- and α_S2-CN are related to changes in milk synthesis and phosphorus secretion in milk. The actual roles of SLC37A1, PAEP, and DGAT1 in α_S1- and α_S2-CN phosphorylation in Dutch Holstein Friesian require further investigation.     

A high-reliability alumina-platinum multilayer system for implantable medical devices

A new Pt-Al₂O₃ multilayer composite system has been developed and validated with an Accelerated Life Test (ALT) to confirm its potential for long-term use in implantable medical devices (IMD). Panels containing over 100 Pt vias were subjected to highly accelerated immersion testing in deionized water at temperatures ranging from 90 to 175°C. Deionized water was employed as it best represents the IMD use environment. Degradation of individual Pt vias was evaluated using fluorescent dye infiltration into the subsurface of the panels. ALT guided refinement of materials and processing to produce a Pt-Al₂O₃ multilayer composite system with promising performance for possible use in implantable devices.     

The effects of strength models in numerical study of metal plate destruction by contact explosive charge

Based on a complete mathematical model, the authors set up a problem of metal plate destruction by contacting explosive charge in highly nonlinear dynamic software AUTODYN and solved in two cases using the Johnson–Cook and von Mises strength models. The numerical simulation results were compared with the experimental results and showed a good fit of numerical calculations versus experiments by using the von Mises strength model. The study also shows that the Johnson–Cook strength model, if applied unreasonably, will lead to large errors, which would help to avoid mistakes in the future high speed impact study.     

Science and Engineering in the Petascale Era

What breakthrough advances will petascale computing bring to various science and engineering fields? Experts in everything from astronomy to seismology envision the opportunities ahead and the impact they'll have on advancing our understanding of the world.     

Interactive Improvisational Music Companionship: A User-Modeling Approach

User Modeling and User-Adapted Interaction -