Effect of succinylation on the functional properties of yak caseins: a comparison with cow caseins

Effect of Extraction Methods and Preheat Treatments on the Functional Properties of Pumpkin Seed Protein Concentrate

This study explores the effect of different extraction methods and preheat treatments in obtaining protein concentrate from pumpkin seed flour. The effects on the yield and functional properties of pumpkin seed protein concentrate (PSPC) were compared alongside microwave and conventional preheating methods using alkali, salt, and enzyme-assisted alkali extraction techniques. Analytical assessments included proximate analysis, soluble protein content, water solubility index (WSI), emulsification activity (EA) and stability (ES), foaming capacity (FC) and stability (FS), and antioxidant activity (AA). Hydration and structural analyses were performed via time-domain nuclear magnetic resonance (TD-NMR) Relaxometry and Fourier-Transform Infrared (FTIR) Spectroscopy. In addition, color measurements were performed to evaluate the visual quality of the samples. The alkali extraction method paired with microwave heating (MH-AE) significantly outperformed other techniques, with an extraction yield and protein content of approximately 55% and 77%, respectively. This study demonstrated the superior yield and functional properties of PSPC using MH-AE, opening opportunities for future research in optimizing plant-based protein extraction techniques.

Effect of ohmic heating-assisted glycation reaction on the properties of soybean protein isolate-chitosan complexes

The purpose of this study was to investigate the progress of glycation reaction reactions by conventional heating and ohmic heating (OH) treatment, and the effect of different electric field intensities on the structure, physical and chemical and functional properties of glycosylated proteins. The findings demonstrated that OH treatment was more efficacious than conventional heating in reducing the free amino group and increasing the absorbance at 420 nm. Concurrently, the α-helix and β-sheet content of soy protein isolate (SPI)-chitosan (CS) complexes exhibited a reduction to 18.01 % and 28.67 %, respectively, while the UV absorption peak demonstrated an increase in conjunction with the escalation of electric field intensity. When the electric field intensity was 6 V/cm, the emulsification activity index and emulsion stability index of SPI-CS complexes were found to be 95.52 m2/g and 55.60 min, respectively. The foaming capacity and foaming stability were found to be 148.33 % and 115.59 % respectively, while the solubility was also up to 91.37 %. Additionally, the air/water interface properties demonstrated a notable enhancement. The functional properties of the complexes were demonstrably enhanced following the application of an OH treatment. The aforementioned statement provided a theoretical foundation for the implementation of OH treatment.

Effect of low degree succinylation on properties of enzyme-induced casein hydrogel

This study examines the impact of succinic anhydride (SA) modification (0-9 %) on the gel properties of casein. Upon succinylation, the surface hydrophobicity (H0) of casein initially increased before decreasing, achieving its peak at a degree of succinylation of 5.22 ± 0.16 %. The α-helix content rose to 14.13 ± 2.60 %, and the -OH peak shifted towards lower wavenumbers, suggesting enhanced hydrogen bonding within intra/intermolecular structures. The storage modulus in the rheological test escalated from 2160.11 Pa to 5047.60 Pa, and SEM analysis revealed that the optimally succinylated casein gel formed a denser and more stable gel network structure. Moreover, succinylated casein hydrogels demonstrated superior texture properties, swelling ability, and thermal stability. Molecular dynamics simulation (MD) results suggest that SA preferentially binds to LYS27 and LYS28 of β-casein via hydrogen bonds and amide bonds, respectively. The interaction between modified proteins is primarily governed by hydrogen bonds, aligning with FT-IR findings. PCA analysis identified a positive correlation between the ordered structure and gel performance. This research offers theoretical insights and reference data for modulating casein hydrogel properties through succinylation.

Casein Micelles as an Emerging Delivery System for Bioactive Food Components

Bioactive food components have potential health benefits but are highly susceptible for degradation under adverse conditions such as light, pH, temperature and oxygen. Furthermore, they are known to have poor solubilities, low stabilities and low bioavailabilities in the gastrointestinal tract. Hence, technologies that can retain, protect and enable their targeted delivery are significant to the food industry. Amongst these, microencapsulation of bioactives has emerged as a promising technology. The present review evaluates the potential use of casein micelles (CMs) as a bioactive delivery system. The review discusses in depth how physicochemical and techno-functional properties of CMs can be modified by secondary processing parameters in making them a choice for the delivery of food bioactives in functional foods. CMs are an assembly of four types of caseins, (α_s1, α_s2, β and κ casein) with calcium phosphate. They possess hydrophobic and hydrophilic properties that make them ideal for encapsulation of food bioactives. In addition, CMs have a self-assembling nature to incorporate bioactives, remarkable surface activity to stabilise emulsions and the ability to bind hydrophobic components when heated. Moreover, CMs can act as natural hydrogels to encapsulate minerals, bind with polymers to form nano capsules and possess pH swelling behaviour for targeted and controlled release of bioactives in the GI tract. Although numerous novel advancements of employing CMs as an effective delivery have been reported in recent years, more comprehensive studies are required to increase the understanding of how variation in structural properties of CMs be utilised to deliver bioactives with different physical, chemical and structural properties.

Succinylation Improves the Thermal Stability of Egg White Proteins

Succinylation can improve the thermal stability of various proteins. In this study, succinylated egg white protein (SEWP) samples with different succinylation degrees were prepared by adding various succinic anhydride additives to egg white protein (EWP). The thermal stability of SEWP and the conformational structure under various succinylation degrees were investigated. With the increase in succinylation degree, the turbidity of heated SEWP solution (90 °C for 30 min) markedly declined. The heated SEWP solution with high succinylation degree (37.63%, 66.57%, and 72.37%) was transparent. Moreover, the result of differential scanning calorimetry confirmed that the thermal stability of succinylated EWP increased. The results of intrinsic fluorescence spectra and Fourier-transform infrared spectroscopy illustrate that succinylation changed the conformational structure of EWP. Succinylation increased the electrostatic repulsion and decreased the surface hydrophobicity, and it changed the aggregation morphology of EWP. Cross-linked spherical aggregates of low succinylation degree transformed to thready aggregates of a high succinylation degree. Thus, succinylation improved the thermal stability of EWP.

Succinylated whey protein isolate as a sustained-release excipient of puerarin derivative oral tablets: Preparation, optimization and pharmacokinetics

This work was done to investigate succinylated commercial whey protein isolate (S-WPI) as an oral sustained-release delivery carrier for puerarin 5 (PR-5). The succinylation conditions were established for S-WPIs by optimization of single factor study and Box–Beehnken design. The effect of succinylation degree on S-WPIs solubility was evaluated. Physicochemical properties of S-WPIs dried by different three methods on their flow ability, particle size, morphology and in vitro release behavior were studied. After preparing PR-5 sustained release protein tablets with S-WPIs as the carrier by direct powder compression method, the drug release were studied in vitro and the oral pharmacokinetics and bioavailability was evaluated using in vivo dog model. It was observed that concentration of substrate has a significant effect on succinylation. Release behavior in vitro showed spry dried S-WPIs with 100% succinylation rate and 30% drug loading would be applied to the preparation of PR-5 sustained-release protein tablets based on the swelling mechanism (protein loss). Compared with PR-5 conventional tablet with oral administration, T_max value of PR-5 sustained-release protein tablets was approximately 1.58 fold greater than those of the conventional tablets as further evidenced by the significantly prolonged MRT and T_1/2. The findings demonstrated that spray-dried S-WPIs has potential as a promising functional excipient for the design of PR-5 oral sustained-release tablets which can fully improve sustained-release effect and oral bioavailability.