The Technology and Composition of Functional Food Ingredients Obtained by Sorption of the Polyphenolic Compounds From Cranberry on Coagulated Egg Albumen

The technologies for developing food products for people with type 2 diabetes involve enrichment with polyphenolic compounds that have hypoglycemic and/or hypolipidemic properties. The production of ingredients for introduction into such food products should involve the techniques of concentration of natural polyphenols on certain food-grade protein matrices. In this study, a technology was developed for the production of a functional food ingredient, which was a complex of polyphenols (mostly anthocyans) from cranberries with coagulated egg albumen. The optimal parameters of sorption of anthocyans from cranberry juice on the albumen during the coagulation of the latter were determined. The contents and profile of anthocyans within the resulting food ingredient were assessed. The concentration of total anthocyans (recalculated to equivalents of cyanidin-3-glucoside) was determined by pH-differential spectrophotometry; the profile of individual anthocyans was determined by highperformance liquid chromatography. Sensory evaluation of the resulting ingredient (through a taste panel test) evidenced the possibility of including the product in the functional foodstuffs. The technology developed can be used in the design of functional food ingredients for subsequent introduction into anti-diabetic food products. Keywords: coagulated egg albumen, cranberry juice, anthocyans, functional food ingredients

Encapsulation of Cinnamic Acid on Plant-Based Proteins: Evaluation by HPLC, DSC and FTIR-ATR

Plant-based protein matrices can be used for the formulation of delivery systems of cinnamic acid. Pumpkin, pea and almond protein matrices were used for the formulation of dried complexes. The matrices were used in varying amounts (1%, 2%, 5% and 10%) whilst the amount of cinnamic acid was maintained constant. The obtained complexes were analyzed by HPLC, DSC and FTIR-ATR. The highest amounts of cinnamic acid were determined on complexes prepared by the lowest amounts of protein matrices, regardless of their type. The highest affinity for cinnamic acid adsorption was determined for the pumpkin protein matrix. DSC analysis revealed that adsorption of cinnamic acid caused an increase in the thermal stability of the almond protein matrix, while the other two matrices had the opposite behavior. The complexation of protein matrices and cinnamic acid was proven by recording the IR spectra. The obtained complexes could have potential applications in food products to achieve enrichment with cinnamic acid as well as proteins.

Adsorption/Desorption Behaviors and SERS Chemical Enhancement of 6-Mercaptopurine on a Nanostructured Gold Surface: The Au20 Cluster Model

Computational approaches are employed to elucidate the binding mechanism and the SERS phenomenon of 6-mercaptopurine (6MP) adsorbed on the tetrahedral Au20 cluster as a simple model for a nanostructured gold surface. Computations are carried out in both vacuum and aqueous environments using a continuum model. In the gaseous phase and neutral conditions, interaction of 6MP with the gold cluster is mostly dominated by a covalent Au−S bond and partially stabilized by the Au⋅⋅⋅H−N coupling. However, in acidic solution, the nonconventional Au⋅⋅⋅H−S hydrogen-bond becomes the most favorable binding mode. The 6MP affinity for gold clusters decreases in the order of vacuum > neutral solution > acidic medium. During the adsorption, the energy gap of Au20 substantially declines, leading to an increase in its electrical conductivity, which can be converted to an electrical noise. Moreover, such interaction is likely a reversible process and triggered by either the low pH in sick tissues or the presence of cysteine residues in protein matrices. While N−H bending and stretching vibrations play major roles in the SERS phenomenon of 6MP on gold surfaces in neutral solution, the strongest enhancement in acidic environment is mostly due to an Au⋅⋅⋅H−S coupling, rather than an aromatic ring-gold surface π overlap as previously proposed.

A computational study of mercaptopurine and thioguanine binding to gold clusters Aun (n = 3, 4)

The density functional theory calculations are employed to elucidate the adsorption/desorption behaviours of mercaptopurine (MP) and thioguanine (TG) drugs on the gold surfaces, using Au3 and Au4 clusters as model reactants. The PBE functional in combination with the effective core potential cc-pVTZ-PP basis set for gold atoms and cc-pVTZ basis set for nonmetals have been used to investigated geometric structures, thermodynamic parameters and electronic properties of the obtained complexes. The IEF-PCM model with water solvent was used to include the effect of biological environment on the interactions. The computed results show that the binding is dominated by a covelant bond Au−S and by electrostatic effects, namely a hydrogen bond contribution NH∙∙∙Au. In addition, the drug binding to gold clusters is a reversible process and a drug release mechanism was also clarified. Accordingly, the drugs are willing to separate from the gold surface due to either a slight change of pH in tumor cells or the presence of cysteine residues in protein matrices.

Recombinant Spider Silk Protein Matrices Facilitate Differentiation of Neural Stem Cells Into Mature and Functional Neurons

Neural stem cells (NSCs) show great promise in drug discovery and clinical application. Yet few efforts have been made to optimize biocompatible materials for such cells to be expanded and used in clinical conditions. We have previously demonstrated that NSCs are readily cultured on substrates of certain recombinant spider silk protein without addition of animal- or human-derived components. The question remains however whether this material allows differentiation into functional neurons, and whether such differentiation can take place also when the NSCs are cultured not only upon but also within the biodegradable material. Here we demonstrate that “foam”-like structures generated from recombinant spider silk protein (4RepCT) provided excellent matrices for the generation and multicellular analysis of functional excitatory neurons from NSCs without addition of animal- or human-derived components. NSCs isolated from the cerebral cortices of rat embryos were cultured at either 4RepCT matrices shaped as foam-like structures without coating, or on conventional polystyrene plates coated with poly-L-ornithine and fibronectin. Upon treatment with recombinant proteins including the extracellular signaling factor BMP4 or a combination of BMP4 and the signaling factor Wnt3a, the cortical NSCs cultured in 4RepCT foam-like structures differentiated efficiently into neurons that responded to glutamate receptor agonists, such as AMPA, to the same extent as control cultures. Matrices derived from recombinant spider silk proteins thus provide a functional microenvironment for neural stem cells with little or no animal- or human-derived components and can be employed in the development of new strategies in stem cell research and tissue engineering.

Photon upconverting bioplastics with high efficiency and in-air durability

The accommodation of chromophore-dissolved microdroplets in semicrystalline protein matrices succeeds in achieving upconverting bioplastics with high efficiency, air-stability, and long-term durability for the first time.

Improving the accuracy of unbound fraction measurement of drug-protein binding by preconditioning the RED membrane inserts

Aim: The objective of this study was to evaluate the rapid equilibrium dialysis (RED) device in protein binding assays in diluted protein matrices and to improve the accuracy of the unbound fraction ( fu) measurement. Methodology: Protein binding assays of drug compounds in bovine serum albumin solutions and human plasma with different folds of dilution were performed using the RED device with and without preconditioning of the dialysis membrane inserts, and the results were compared with those using other approaches in this study. Results & conclusion: Preconditioning of the RED membrane inserts improved the fu data accuracy of drug-protein binding assay in matrices with relatively low protein contents and such impact could be compound dependent.

Toward the Genetic Basis and Multiple QTLs of Kernel Hardness in Wheat

Kernel hardness is one of the most important single traits of wheat seed. It classifies wheat cultivars, determines milling quality and affects many end-use qualities. Starch granule surfaces, polar lipids, storage protein matrices and Puroindolines potentially form a four-way interaction that controls wheat kernel hardness. As a genetic factor, Puroindoline polymorphism explains over 60% of the variation in kernel hardness. However, genetic factors other than Puroindolines remain to be exploited. Over the past two decades, efforts using population genetics have been increasing, and numerous kernel hardness-associated quantitative trait loci (QTLs) have been identified on almost every chromosome in wheat. Here, we summarize the state of the art for mapping kernel hardness. We emphasize that these steps in progress have benefitted from (1) the standardized methods for measuring kernel hardness, (2) the use of the appropriate germplasm and mapping population, and (3) the improvements in genotyping methods. Recently, abundant genomic resources have become available in wheat and related Triticeae species, including the high-quality reference genomes and advanced genotyping technologies. Finally, we provide perspectives on future research directions that will enhance our understanding of kernel hardness through the identification of multiple QTLs and will address challenges involved in fine-tuning kernel hardness and, consequently, food properties.