Real-time in-situ quantification of protein secondary structures in aqueous solution based on ATR-FTIR subtraction spectrum

Effect of Polygonatum cyrtonema Hua polysaccharides on gluten structure, in vitro digestion and shelf-life of fresh wet noodle

This study aimed to investigate the effects of raw Polygonatum cyrtonema Hua polysaccharides (RPCPs) and "zhi" P. cyrtonema Hua polysaccharides (ZPCPs) on the gluten structure, in vitro digestion, and shelf life of fresh wet noodles (FWN). The results demonstrated that incorporating PCPs improved the cooking and sensory qualities of FWN. Moreover, the shelf life of FWN was extended by 6 days with 1.5 % RPCPs (w/w) compared with the control FWN. Furthermore, incorporating 1.5 % ZPCPs led to a 1.2- and 0.2-fold increase in the disulfide bond and α-helix content, respectively, compared with the control FWN. This resulted in enhanced gluten structure, improved springiness and viscidity, and reduced cooking loss by 14.47 %-52.19 %. The scanning electron microscopy analysis revealed that the starch particles were entrapped by PCPs, leading to higher gelatinization temperature and lower setback value of FWN, thereby reducing the starch digestion ratio to 55.50 %. In summary, the findings suggested that FWN containing PCPs can extend shelf life, improve taste, and slow starch digestion staple.

Immobilized Cellulase on NH2-MIL-88(Fe) and Its Performance as a Biocatalyst

To broaden pH range and improve thermal stability, reusability, storage stability, and organic solvent tolerance of natural enzymes, a magnetic material (NH2-MIL-88(Fe)) was synthesized as a new material to immobilize cellulase. The results showed that the optimal temperature and pH of cellulase immobilized on NH2-MIL-88(Fe) showed a wider range compared to free cellulase, and 74% and 83% of the initial activity could be retained after 10 cycles and storage for 49 days, respectively. Moreover, the tolerance for organic solvents was improved compared with free enzyme. The reducing sugar yields from sodium carboxymethylcellulose (CMC) and corn cob hydrolyzed with cellulase immobilized on NH2-MIL-88(Fe) were higher than observed with the free enzyme, which demonstrated the better biocatalytic performance of cellulase immobilized on NH2-MIL-88(Fe).

pH-responsive multi-network composite cellulose-based hydrogels for stable delivery of oral IgY-Fab fragments

Yolk immunoglobulin (IgY) is perfect supplement to mammalian immunoglobulin G in passive immune protection but with poor delivery stability. This work succeeded in pH-responsive oral delivery of IgY-Fab fragments with cellulose based multi-network composite hydrogels. Data displayed that the hydrogel 2 showed superior mechanical properties and load performance (encapsulation efficiency of 99.25% and loading capacity of 45.11 mg/100 mg). The stability of the released Fab was confirmed by HPLC with Fab purity up to 79.65% at the end of digestion. The FTIR spectra revealed the potential interactions between Fab and the hydrogel matrix of the formation of hydrogen bonds or electrostatic interactions between the groups of -OH, -CH2, and -COO-. The excellent rehydration of the hydrogels wouldn't be impacted by low-temperature freeze drying. In sum, this work is of great significance to the development of Fab-themed health-care food, intensive processing of poultry eggs and the economic construction of related industries.

Mechanisms of Biomolecular Self-Assembly Investigated Through In Situ Observations of Structures and Dynamics

Biomolecular self-assembly of hierarchical materials is a precise and adaptable bottom-up approach to synthesizing across scales with considerable energy, health, environment, sustainability, and information technology applications. To achieve desired functions in biomaterials, it is essential to directly observe assembly dynamics and structural evolutions that reflect the underlying energy landscape and the assembly mechanism. This review will summarize the current understanding of biomolecular assembly mechanisms based on in situ characterization and discuss the broader significance and achievements of newly gained insights. In addition, we will also introduce how emerging deep learning/machine learning-based approaches, multiparametric characterization, and high-throughput methods can boost the development of biomolecular self-assembly. The objective of this review is to accelerate the development of in situ characterization approaches for biomolecular self-assembly and to inspire the next generation of biomimetic materials.

Nanocellulose aerogels as 3D amyloid templates

Proteins in solution tend to coat solid surfaces upon exposure. Depending on the nature of the surface, the environmental conditions, and the nature of the protein these adsorbed proteins may self-assemble into ordered, fibre-like structures called amyloids. Nanoparticulate surfaces, with their high surface to volume ratio, are particularly favourable to amyloid formation. Most prior research has focussed on either inorganic or organic nanoparticles in solution. In this research, we instead focus on aerogels created from TEMPO-oxidized cellulose nanofibers (TO-CNF) to serve as bio-based, three-dimensional amyloid templates with a tuneable surface chemistry. Previous research on the use of cellulose as a protein adsorption template has shown no evidence of a change in the secondary protein structure. Herein, however, with the aid of the reducing agent TCEP, we were able to induce the formation of amyloid-like 'worms' on the surface of TO-CNF aerogels. Furthermore, we demonstrate that the addition of the TO-CNF aerogel can also induce bulk aggregation under conditions where it previously did not exist. Finally, we show that the addition of the aerogel increases the rate of 'worm' formation in conditions where previous research has found a long lag-phase. Therefore, TO-CNF aerogels are shown to be excellent templates for inducing ordered protein aggregation.

Haem-mediated protein oxidation affects water-holding capacity of beef during refrigerated storage

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Both deoxymyoglobin and oxymyoglobin in muscle were converted to highly oxidised metmyoglobin.

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More free iron in muscle led to protein and lipid oxidation.

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Myoglobin, haemoglobin, protein and lipid oxidation occured simultaneously in beef during refrigeration.

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Free iron and metmyoglobin were the main oxidation catalysts in beef.

Haem is considered to be a potential producer of meat oxidation and the effect of its mediated oxidation on the water holding capacity (WHC) of beef is not yet clear. This work investigated the interrelationships between haem, protein and lipid oxidation, and WHC in beef during refrigerated storage. The increase in juice loss during storage (p < 0.05) indicates a reduction in WHC. Haem was oxidised, resulting in its structural disruption and an increase in the proportion of random coil in the protein secondary structures (p < 0.05). Extractable haem iron content was decreased and non-haem iron content was increased (p < 0.05), indicating the degradation of haem and the release of iron during storage. The levels of lipid and protein oxidation products significantly increased throughout the storage time (p < 0.05). Furthermore, Spearman analysis verified significant correlations between these changes. In conclusion, these processes are mutually reinforcing and may exacerbate muscle juice loss.