Effects of dynamic high-pressure microfluidization on the physicochemical, structural and functional characteristics of Eucommia ulmoides Oliv. seed meal proteins

Isolation and characterization of nettle (Urtica dioica L.) seed proteins: Conversion of underutilized by-products of the edible oil industry into food emulsifiers

This study aimed to upcycle a byproduct of the edible oil industry, cold-pressed nettle seed meal (CPNSM), into a plant-based emulsifier, thereby increasing the sustainability of the food system. The protein content of the nettle seed protein (NSP) powder was 48.3% with glutamic acid (16.6%), asparagine (10.7%), and arginine (9.7%) being the major amino acids. NSPs had a denaturation temperature of 66.6 °C and an isoelectric point of pH 4.3. They could be used as emulsifiers to form highly viscous coarse corn oil-in-water emulsions (10% oil, 4% NSP). Nevertheless, 10-fold diluted emulsions exhibited rapid creaming under different pH (2-9), salt (0-500 mM NaCl) and temperature (>40 °C) conditions, but they were relatively stable to aggregation. Our findings suggest that NSPs could be used as emulsifiers in highly viscous or gelled foods, like dressings, sauces, egg, cheese, or meat analogs.

Effect of dietary Eucommia ulmoides oliver polysaccharide on immune function and meat quality of Songliao Black Pigs

Eucommia ulmoides is a traditional Chinese herbal medicine, with pharmacological effects such as lowering blood pressure and enhancing immune function. The effects of dietary Eucommia ulmoides polysaccharide (EUP) on immune function and meat quality were studied in Songliao Black Pigs. Blood lymphocyte counts and percentage, concentrations of serum total protein and of albumin increased, whereas those of urea nitrogen and triglyceride decreased. White blood cell and lymphocyte counts, and serum IgA, IgE, IgG2 a and IFN-γ increased. Average daily weight gain, slaughter weight, lean meat rate and cooked meat rate increased, whereas pH24, feed-weight ratio, fat rate, yellowness (b#) and centrifugal dehydration rate decreased. Transcriptome sequencing of longissimus dorsi muscle detected 32 differentially expressed genes (DEGs), of which 26 were up-regulated and 6 down-regulated. A total of 19 genes were differentially expressed in the four groups, 18 of which were up-regulated. The DEGs included ADAMTS4, PER1, STAC, SERPINE1, FASN, THRSP, SP7 and KRT80 and the protein interaction network showed 20 up-regulated nodes, three down-regulated nodes and 14 DEGs. GO functional annotation and enrichment analysis showed that 34 items were significantly enriched, including transferase activity, actin binding, acetyl coenzyme A, acyl coenzyme A metabolism, adipose tissue development and acyl glycerol homeostasis. KEGG pathway analysis showed that the AMPK and PPAR signaling pathways were enriched. Dietary Eucommia polysaccharide enhanced immune function in Songliao Black Pigs, improved growth and carcass performance, increased the expression of genes related to meat quality traits and improved meat quality.

Microfluidization improved hempseed yogurt's physicochemical and storage properties

BACKGROUND

Plant-based yogurts are suffering from the common problems, such as an unattractive color, stratified texture state and rough taste. Therefore, it is urgent to develop a novel processing method to improve the quality and extend the storage life of hempseed yogurt. In the present study, hempseed yogurt was microfluidized prior to fermentation. The effects of microfluidization on microstructure, particle size, mechanical properties, sensory acceptability, variations in pH and titratable acidity, lactic acid bacteria (LAB) counts, and stability of hempseed yogurt during 20 days of storage were investigated.

RESULTS

Microfluidization contributed to the production of hempseed yogurt as a result of the better physicochemical properties compared to normal homogenization. Specifically, microfluidization reduced the particle size of hempseed yogurt with a uniform particle distribution, increased water holding capacity, and improved texture and rheological properties. These advancements resulted in higher sensory scores for the yogurt. Furthermore, during storage, microfluidization effectively inhibited the post-acidification process of hempseed yogurt, and increased LAB counts and storage stability.

CONCLUSION

Microfluidization improved the physicochemical properties and storage stability of hempseed yogurt. Our findings support the application of microfluidization in hempseed yogurt and provide a new approach for enhancing the quality of plant-based alternatives that meet consumers' demands for high-quality food products. © 2023 Society of Chemical Industry.

Effect of dynamic high-pressure microfluidization treatment on soybean protein isolate-rutin non-covalent complexes

In this investigation, soybean protein isolate-rutin (SPI-RT) complexes were treated using dynamic high-pressure microfluidization (DHPM). The effects of this process on the physicochemical and thermodynamic properties of SPI were investigated at different pressures. Fourier-transform infrared spectroscopy and fluorescence spectroscopy provided evidence that the SPI structure had been altered. The binding of SPI to RT resulted in a decrease in the percentage of α-helices and random curls as well as an increase in the percentage of β-sheets. In particular, the α-helix content decreased from 29.84 % to 26.46 %, the random curl content decreased from 17.45 % to 15.57 %, and the β-sheet content increased from 25.37 % to 26.53 %. Moreover, fluorescence intensity decreased, and the emission peak of the complex was red-shifted by 6 nm, exposing the internal groups. Based on fluorescence quenching analysis, optimal SPI-RT complexation was achieved after 120-MPa DHPM treatment, and molecular docking analysis verified the interaction between SPI and RT. The minimum particle size, maximum absolute potential, and total phenolic content of the complexes were 78.06 nm, 21.4 mV and 74.35 nmol/mg protein, respectively. Furthermore, laser confocal microscopy revealed that the complex particles had the best microstructure. Non-covalent interactions between the two were confirmed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Moreover, the hydrophobicity of the complex particle's surface increased to 16,045 after 120-MPa DHPM treatment. The results of this study suggest that DHPM strongly promotes the improvement of the physicochemical properties of SPI, and provide a theoretical groundwork for further research.

Microfluidized hemp protein isolate: an effective stabilizer for high-internal-phase emulsions with improved oxidative stability

BACKGROUND

Hemp protein isolates (HPIs), which provide a well-balanced profile of essential amino acids comparable to other high-quality proteins, have recently garnered significant attention. However, the underutilized functional attributes of HPIs have constrained their potential commercial applications within the food and agriculture field. This study advocates the utilization of dynamic-high-pressure-microfluidization (DHPM) for the production of stable high-internal-phase emulsions (HIPEs), offering an efficient approach to fully exploit the potential of HPI resources.

RESULTS

The findings underscore the effectiveness of DHPM in producing HPI as a stabilizing agent for HIPEs with augmented antioxidant activity. Microfluidized HPI exhibited consistent adsorption and anchoring at the oil-water interface, resulting in the formation of a dense and compact layer. Concurrently, the compression of droplets within HIPEs gave rise to a polyhedral framework, conferring viscoelastic properties and a quasi-solid behavior to the emulsion. Remarkably, HIPEs stabilized by microfluidized HPI demonstrated superior oxidative and storage stability, attributable to the establishment of an antioxidative barrier by microfluidized HPI particles.

CONCLUSION

This study presents an appealing approach for transforming liquid oils into solid-like fats using HPI particles, all without the need for surfactants. HIPEs stabilized by microfluidized HPI particles hold promise as emerging food ingredients for the development of emulsion-based formulations with enhanced oxidative stability, thereby finding application in the food and agricultural industries. © 2023 Society of Chemical Industry.

Dynamic microfluidic-assisted transglutaminase modification of soy protein isolate-chitosan: Effects on structural and functional properties of the adduct and its antioxidant activity after in vitro digestion

In this study, soy protein isolate (SPI)-chitosan (CS) adducts were prepared by using dynamic microfluidic-assisted transglutaminase (TGase) modification. It was shown that the solubility and degree of binding of SPI-CS adducts prepared by dynamic microfluidic-assisted TGase modification were better. After the samples were treated twice at 400 bar, the degree of binding for SPI-CS adducts increased to 31.97 ± 1.31%, and the solubility increased to 66.25 ± 1.10%. With the increase of microfluidic pressure, the exposed free sulfhydryl groups increased, the particle size reduced, and the surface hydrophobicity first increased and then decreased. Under the action of the pressure generated by microfluidics, the structure of the protein in the SPI-CS adduct was unfolded and transformed from an ordered structure to a disordered one. The SPI-CS adducts prepared with assisted dynamic microfluidic treatment showed significantly higher ABTS radical scavenging rate, DPPH radical scavenging rate and reducing power after in vitro digestion compared with that of SPI-CS adducts prepared with TGase alone. This result indicated that appropriate dynamic microfluidic treatment improved the structural and functional properties of TGase-modified SPI-CS adducts and significantly increased the antioxidant activity after in vitro digestion.

Effects of different mechanical processes on the structural and powdery properties of insoluble undenatured type II collagen

This study aimed to investigate the effects of dynamic high-pressure homogenization (DHPH), dynamic high-pressure microfluidization (DHPM), and wet media milling (WMM) processes on the particle size, microstructure, triple helix structure, wettability and suspension stability of insoluble undenatured type II collagen (IUC-II). The structural and powdery properties were regulated by different processes and parameters. By contrast, WMM-treated IUC-II showed smallest particle size (15.70 μm), highest wetting rate (216.94 mm/h) and best suspension stability. However, individual mechanical processes caused partial disruption of IUC-II triple helix structure. Low-acyl gellan gum (LAGG) could bind to IUC-II through hydrogen bonds and hydrophobic interactions, which protected the triple helix structure and further enhanced powdery properties of IUC-II treated by WMM process, but restrained the soluble transition during digestion. These results demonstrated that WMM process was more suitable for enhancing powdery properties of IUC-II, while the triple helix structure of IUC-II could be effectively protected by LAGG.

Combined Neutrase-Alcalase Protein Hydrolysates from Hazelnut Meal, a Potential Functional Food Ingredient

Consumers' interest in functional foods has significantly increased in the past few years. Hazelnut meal, the main valuable byproduct of the hazelnut oil industry, is a rich source of proteins and bioactive peptides and thus has great potential to become a valuable functional ingredient. In this study, hazelnut protein hydrolysates obtained by a single or combined hydrolysis by Alcalase and Neutrase were mainly characterized for their physicochemical properties (SDS-PAGE, particle size distribution, Fourier-transform infrared (FTIR) spectroscopy, molecular weight distribution, etc.) and potential antiobesity effect (Free fatty acid (FFA) release inhibition), antioxidant activity (DPPH and ABTS methods), and emulsifying properties. The impact of a microfluidization pretreatment was also investigated. The combination of Alcalase with Neutrase permitted the highest degree of hydrolysis (DH; 15.57 ± 0.0%) of hazelnut protein isolate, which resulted in hydrolysates with the highest amount of low-molecular-weight peptides, as indicated by size exclusion chromatography (SEC) and SDS-PAGE. There was a positive correlation between the DH and the inhibition of FFA release by pancreatic lipase (PL), with a significant positive effect of microfluidization when followed by Alcalase hydrolysis. Microfluidization enhanced the emulsifying activity index (EAI) of protein isolates and hydrolysates. Low hydrolysis by Neutrase had the best effect on the EAI (84.32 ± 1.43 (NH) and 88.04 ± 2.22 m²/g (MFNH)), while a negative correlation between the emulsifying stability index (ESI) and the DH was observed. Again, the combined Alcalase-Neutrase hydrolysates displayed the highest radical scavenging activities (96.63 ± 1.06% DPPH and 98.31 ± 0.46% ABTS). FTIR results showed that the application of microfluidization caused the unfolding of the protein structure. The individual or combined application of the Alcalase and Neutrase enzymes caused a switch from the β-sheet organization of the proteins to α-helix structures. In conclusion, hazelnut meal may be a good source of bioactive and functional peptides. The control of its enzymatic hydrolysis, together with an appropriate pretreatment such as microfluidization, may be crucial to achieve the best suitable activity.

Valorization of green biomass Azolla pinnata fern: multi-parameter evaluation of processing conditions on protein extractability and their influence on the physicochemical, structural, techno-functional properties and protein quality

BACKGROUND

This study determined the effect of processing conditions on protein extractability from Azolla pinnata fern, and their influence on the physicochemical, structural, techno-functional properties and protein quality.

RESULTS

The protein extraction from A. pinnata fern was optimized through response surface methodology obtaining a maximum yield of 18.93% with a recovery rate of 73.66%. The A. pinnata fern protein concentrate (AFPC) had five protein bands with a molecular weight ranging from 17 to 56 kDa. AFPC contained high β-sheet structure (36.61%), favouring its good thermal properties with three endothermic peaks at 54.28, 86.52 and 166.25 °C. The AFPC scored ≥ 1 for all essential amino acids, except for lysine and histidine. The AFPC exhibited exceptionally high techno-functional properties, particularly for water holding (5.46 g g^-1 ) and fat absorption capacity (10.08 g g^-1 ), and gelling properties (5% gelation concentration). The AFPC had high in vitro digestibility of 73%, signifying its high availability for human consumption.

CONCLUSION

The underexploited A. pinnata fern is a potential source of edible protein, thus a promising nutraceutical or ingredient of functional and health-promoting foods. © 2022 Society of Chemical Industry.

Dynamic high pressure treatments: current advances on mechanistic-cum-transport phenomena approaches and plant protein functionalization

Dynamic high pressure treatment (DHPT) either by high pressure homogenization or microfluidisation, is an emerging concept used in the food industry for new products development through macromolecules modifications in addition to simple mixing and emulsification action. Mechanistic understanding of droplets breakup during high pressure homogenization is used to understand how these compact and high molecular weight-sized globular plant proteins are affected during DHPTs. Plant protein needs to be functionalized for advanced use in food formulation. DHPTs brought changes in plant proteins' secondary, tertiary, and quaternary structures through alterations in intermolecular and intramolecular interactions, sulfhydryl groups, and disulfide bonds. These structural changes in plant proteins affected their functional and physicochemical properties like solubility, oil and water holding capacity, gelation, emulsification, foaming, and rheological properties. These remarkable changes made utilization of this concept in novel food system applications like in plant-based dairy analogues. Overall, this review provides a comprehensive and critical understanding of DHPTs on their mechanistic and transport approaches for droplet breakup, structural and functional modification of plant macromolecules. This article also explores the potential of DHPT for formulating plant-based dairy analogues to meet healthy and sustainable food consumption needs. HIGHLIGHTSIt critically reviews high pressure homogenization (HPH) and microfluidisation (DHPM).It explores the mechanistic and transport phenomena approaches of HPH and DHPMHPH and DHPM can induce conformational and structural changes in plant proteins.Improvement in the functional properties of HPH and DHPM treated plant proteins.HPH and DHPM are potentially applicable for plant based dairy alternatives food system.

Latest developments in the applications of microfluidization to modify the structure of macromolecules leading to improved physicochemical and functional properties

Microfluidization is a unique high-pressure homogenization technique combining various forces such as high-velocity impact, high-frequency vibration, instantaneous pressure drop, intense shear rate, and hydrodynamic cavitation. Even though it is mainly used on emulsion-based systems and known for its effects on particle size and surface area, it also significantly alters physicochemical and functional properties of macromolecules including hydration properties, solubility, viscosity, cation-exchange capacity, rheological properties, and bioavailability. Besides, the transformation of structure and conformation due to the combined effects of microfluidization modifies the material characteristics that can be a base for new innovative food formulations. Therefore, microfluidization is being commonly used in the food industry for various purposes including the formation of micro- and nano-sized emulsions, encapsulation of easily degradable bioactive compounds, and improvement in functional properties of proteins, polysaccharides, and dietary fibers. Although the extent of modification through microfluidization depends on processing conditions (e.g., pressure, number of passes, solvent), the nature of the material to be processed also changes the outcomes significantly. Therefore, it is important to understand the effects of microfluidization on each food component. Overall, this review paper provides an overview of microfluidization treatment, summarizes the applications on macromolecules with specific examples, and presents the existing problems.