RESUMO
3D printing is an additive manufacturing technology that locates constructed models with computer-controlled printing equipment. To achieve high-quality printing, the requirements on rheological properties of raw materials are extremely restrictive. Given the special structure and high modifiability under external physicochemical factors, the rheological properties of proteins can be easily adjusted to suitable properties for 3D printing. Although protein has great potential as a printing material, there are many challenges in the actual printing process. This review summarizes the technical considerations for protein-based ink 3D printing. The physicochemical factors used to enhance the printing adaptability of protein inks are discussed. The post-processing methods for improving the quality of 3D structures are described, and the application and problems of fourth dimension (4D) printing are illustrated. The prospects of 3D printing in protein manufacturing are presented to support its application in food and cultured meat. The native structure and physicochemical factors of proteins are closely related to their rheological properties, which directly link with their adaptability for 3D printing. Printing parameters include extrusion pressure, printing speed, printing temperature, nozzle diameter, filling mode, and density, which significantly affect the precision and stability of the 3D structure. Post-processing can improve the stability and quality of 3D structures. 4D design can enrich the sensory quality of the structure. 3D-printed protein products can meet consumer needs for nutritional or cultured meat alternatives.
Assuntos
Tinta , Impressão Tridimensional , Alimentos , Carne in vitro , Substitutos da CarneRESUMO
Condiments (such as sodium chloride and glutamate sodium) cause consumers to ingest too much sodium and may lead to a variety of diseases, thus decreasing their quality of life. Recently, a salt reduction strategy using flavor peptides has been established. However, the development of this strategy has not been well adopted by the food industry. There is an acute need to screen for peptides with salty and umami taste, and to understand their taste characteristic and taste mechanism. This review provides a thorough analysis of the literature on flavor peptides with sodium-reducing ability, involving their preparation, taste characteristic, taste mechanism and applications in the food industry. Flavor peptides come from a wide range of sources and can be sourced abundantly from natural foods. Flavor peptides with salty and umami tastes are mainly composed of umami amino acids. Differences in amino acid sequences, spatial structures and food matrices will cause different tastes in flavor peptides, mostly attributed to the interaction between peptides and taste receptors. In addition to being used in condiments, flavor peptides have also anti-hypertensive, anti-inflammatory and anti-oxidant abilities, offering the potential to be used as functional ingredients, thus making their future in the food industry extremely promising.
RESUMO
BACKGROUND: Recently, fatty fish have been utilized as a potential approach for the fabrication of surimi products, with the yield of fatty fish surimi being > 10 000 tons in 2019. However, the gelling properties of catfish surimi can be influenced by intermuscular lipid. Lipase could effectively enhance the gel quality of catfish surimi gels, although the chemical forces involved in gel formation and alteration in lipid and protein oxidation status are not well understood. The present study investigated the gelation-enhancing effects of lipase on catfish surimi based on changes in chemical oxidation interactions. RESULTS: The addition of 7.5 g kg-1 lipase significantly increased the hydrophobic interactions and disulfide bond contents, both of which facilitated gel formation, in surimi gels. The 2-thiobarbituric acid reactive substance and carbonyl concentrations demonstrated that lipase promoted lipid and protein oxidations. Furthermore, an appropriate dose of malondialdehyde accelerated protein oxidation, thereby resulting in the covalent cross-linking of proteins. Consequently, the gel strength increased from 55.72 to 127.71 g × cm with lipase contents of up to 7.5 g kg-1 , and strong chemical cross-linking and a compact network were observed via sodium dodecyl sulfate polyacrylamide gel electrophoresis and scanning electron microscopy. However, excessive oxidation led to the degeneration of the gel matrix. A schematic mechanism, mainly based on the chemical changes, is proposed. CONCLUSION: The present study revealed the gelation mechanism of catfish surimi gels with lipase, and suggested that lipase treatments may be an effective approach for improving the textural properties of fatty fish surimi gels. © 2021 Society of Chemical Industry.
Assuntos
Produtos Pesqueiros/análise , Proteínas de Peixes/química , Manipulação de Alimentos/métodos , Lipase/química , Animais , Biocatálise , Peixes-Gato , Géis/química , Interações Hidrofóbicas e HidrofílicasRESUMO
BACKGROUND: Refrigeration is commonly used in the processing and storage of surimi products. However, refrigerated surimi products are susceptible to microbial contamination, which leads to deterioration of the products and shortens their shelf life. The aims of the present study were therefore to evaluate the effects of ϵ-polylysine (ϵ-PL) on spoilage bacteria in surimi products, and to investigate the antibacterial mechanism of Bacillus cereus, which is the dominant spoilage bacterium. RESULTS: ϵ-Polylysine with a high degree of polymerization (20-30K) proved able to decrease the total number of colonies in surimi products and showed an obvious antibacterial effect against B. cereus. After ϵ-PL treatments, the distinct broken areas on the bacterial surfaces and the aggregations of cells were observed by scanning electron microscope (SEM). The intracellular materials, such as small molecules, soluble proteins, and deoxyribonucleic acids in the cells were analyzed, which revealed the destructive effects of ϵ-PL on bacterial cells. Experiments with propidium iodide (PI) infiltration experiments verified that the permeability of cell membranes was enhanced by ϵ-PL treatment. CONCLUSION: These results indicated that ϵ-PL could destroy the cell membranes and change the permeability of B. cereus, and subsequently the cell contents leaked out to achieve antibacterial effects. © 2018 Society of Chemical Industry.
Assuntos
Antibacterianos/farmacologia , Bacillus cereus/crescimento & desenvolvimento , Produtos Pesqueiros/microbiologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Polilisina/farmacologia , Antibacterianos/análise , Bacillus cereus/efeitos dos fármacos , Produtos Pesqueiros/análise , Conservação de Alimentos/instrumentação , Conservantes de Alimentos/análise , Polilisina/análise , RefrigeraçãoRESUMO
Antifreeze peptide (AFP) including in frozen protein ink is an inevitable trend because AFP can make protein ink suitable for 3D printing after freezing. AFP-based surimi ink (ASI) was firstly investigated, and the AFP significantly enhanced 3D printability of frozen surimi ink. The rheological and textural results of ASI show that the τ0, K, and n values are 321.14 Pa, 2.2259 × 105 Pa·sn, and 0.19, respectively, and the rupture strength of the 3D structure is up to 217.67 g. Circular dichroism, intermolecular force, and differential scanning calorimeter show ASI has more undenatured protein after freezing when compared that surimi ink (SI), which was denatured, and the α-helix changed to a ß-sheet due to the destruction of hydrogen bonds and the exposure of hydrophobic groups. The water distribution, water holding capacity, and microstructure indicate that ASI effectively binds free water after freezing, while SI has weak water binding capacity and a large amount of free water is formed. ASI is suitable for 3D printing, and can print up to 40.0 mm hollow isolation column and 50.0 mm high Wuba which is not possible with SI. The application of AFP provides guidance for 3D printing frozen protein ink in food industry.
RESUMO
A calcium-mediated three-component selenylation of gem-difluoroalkenes using alcohols as nucleophiles and N-(phenylseleno)phthalimide as the selenylation agent has been developed for the efficient synthesis of various α,α-difluoroalkyl-ß-selenides. This selenylation reaction exhibits broad substrate and functional group tolerance, along with high levels of chemo- and regioselectivity. Additionally, the synthetic utility of the developed transformation in the late-stage functionalization of drug molecules was demonstrated.
RESUMO
Understanding the basic solubilization of fish myofibrillar proteins (MPs) in common monovalent chloride solutions is crucial for muscle food processing. In this study, the differential proteomic profiles of MPs during extraction and solubilization in NaCl and KCl solutions were investigated by using advanced four-dimensional data-independent acquisition (4D DIA) quantitative proteomics for the first time. Compared to routine biochemical analysis, this could provide insights into the solubilization of muscle proteins. We ensure the consistency of the effective ionic strength of NaCl and KCl buffers by adjusting the conductivity. The results showed that NaCl extractor mainly facilitated the solubilization of cytoskeletal proteins, biochemical enzymes, and stromal proteins compared to KCl, such as tubulin, myosin-9, collagen, plectin, protein phosphatase, and cathepsin D. However, no significant difference was observed in the extraction of major sarcomeric proteins, including myosin, actin, troponin C, myosin-binding protein C, M-Protein, α-actinin-3, and tropomyosin.
Assuntos
Proteínas de Peixes , Cloreto de Sódio , Animais , Cloreto de Sódio/farmacologia , Proteínas de Peixes/metabolismo , Proteômica , Miofibrilas/metabolismo , Miosinas/metabolismo , Actinas/metabolismoRESUMO
Metal tellurides (MTes) are highly attractive as promising anodes for high-performance potassium-ion batteries. The capacity attenuation of most reported MTe anodes is attributed to their poor electrical conductivity and large volume variation. The evolution mechanisms, dissolution properties, and corresponding manipulation strategies of intermediates (K-polytellurides, K-pTex) are rarely mentioned. Herein, we propose a novel structural engineering strategy to confine ultrafine CoTe2 nanodots in hierarchical nanogrid-in-nanofiber carbon substrates (CoTe2@NC@NSPCNFs) for smooth immobilization of K-pTex and highly reversible conversion of CoTe2 by manipulating the intense electrochemical reaction process. Various in situ/ex situ techniques and density functional theory calculations have been performed to clarify the formation, transformation, and dissolution of K-pTex (K5Te3 and K2Te), as well as verifying the robust physical barrier and the strong chemisorption of K5Te3 and K2Te on S, N co-doped dual-type carbon substrates. Additionally, the hierarchical nanogrid-in-nanofiber nanostructure increases the chemical anchoring sites for K-pTex, provides sufficient volume buffer space, and constructs highly interconnected conductive microcircuits, further propelling the battery reaction to new heights (3500 cycles at 2.0 A g-1). Furthermore, the full cells further demonstrate the potential for practical applications. This work provides new insights into manipulating K-pTex in the design of ultralong-cycling MTe anodes for advanced PIBs.
RESUMO
The coverage of the protein database directly determines the results of shotgun proteomics. In this study, PacBio single-molecule real-time sequencing technology was performed on postmortem silver carp muscle transcripts. A total of 42.43 Gb clean data, 35,834 nonredundant transcripts, and 15,413 unigenes were obtained. In total, 99.32% of the unigenes were successfully annotated and assigned specific functions. PacBio long-read isoform sequencing (Iso-Seq) analysis can provide more accurate protein information with a higher proportion of complete coding sequences and longer lengths. Subsequently, 2671 proteins were identified in deep 4D proteomics informed by a full-length transcriptomics technique, which has been shown to improve the identification of low-abundance muscle proteins and potential protein isoforms. The feature of the sarcomeric protein profile and information on more than 30 major proteins in the white dorsal muscle of silver carp were reported here for the first time. Overall, this study provides valuable transcriptome data resources and the comprehensive muscle protein information detected to date for further study into the processing characteristic of early postmortem fish muscle, as well as a spectral library for data-independent acquisition and data processing. This batch of muscle-specific dependent acquisition data is available via PRIDE with identifier PXD043702.
Assuntos
Carpas , Transcriptoma , Animais , Proteômica , Proteoma/genética , Carpas/genética , Isoformas de Proteínas/genética , MúsculosRESUMO
Freeze denaturation of protein caused by ice crystals is the main motivation for the quality deterioration of surimi during circulation and storage. This investigation aimed to cryoprotect surimi by adding antifreeze peptides from Takifugu obscurus skin (TsAFP) which can inhibit ice recrystallization, and to elucidate regulating mechanism. The comprehensive results showed that 4% TsAFP, half dosage of commercial cryoprotectant, had good cryoprotection on surimi by reducing the moisture variation and maintaining protein solubility of surimi at macro level, as well as inhibiting the degeneration and structure changes of myofibrillar proteins at micro level. Meanwhile, TsAFP could directly bind to the structural cavity of myosin, inhibit protein freezing-induced oxidation, maintain the spatial structure of myosin and water retention ability to preserve the surimi quality. This study helped better comprehend the protective mechanisms of antifreeze peptides in frozen surimi and was expected to provide a promising cryoprotectant for low-sweetness and low-calorie surimi.
Assuntos
Crioprotetores , Gelo , Congelamento , Crioprotetores/farmacologia , Crioprotetores/química , Miosinas , Proteínas AnticongelantesRESUMO
The effects of freeze-thaw (F-T) cycles on the shape retention of antifreeze peptides-based surimi ink (ASI) 3D structures were analyzed. The results showed that the ASI 3D structure has good shape retention ability, and the width, height, weight, and water holding capacity were 22.42 mm, 21.07 mm, 9.99 g, and 68.30 % even after F-T 4 times, respectively. The average area and equivalent diameter of ice crystals in ASI 3D structures only expand from 0.001 mm2 and 0.040 mm to 0.015 mm2 and 0.139 mm, respectively. The α-helix and ß-sheet of myofibrillar protein in ASI 3D structure were slightly decreased by 44.16 ± 0.98 % to 33.33 ± 0.92 % and increased by 18.28 ± 4.45 % to 24.43 ± 1.60 %, respectively. The chemical bond and protein interaction have changed to some extent. AFPs can prevent denaturation and juice loss of surimi 3D structures after F-T. The results provide theoretical guidance for maintaining the shape retention of frozen 3D food structures.
Assuntos
Proteínas Anticongelantes , Alimentos Congelados , Congelamento , Proteínas Anticongelantes/química , Água/química , GeloRESUMO
Moderately processed surimi products exhibit better nutrient retention and enhanced gels, and the great potential of microwaves application and changes in the way of chopping meat has been reported by previous research. In this study, a systematic analysis of the novel surimi product was made to explore the heat and mass transfer characteristics. A porous media model combining electromagnetic heat and hygroscopic expansion was developed to evaluate this process, and its accuracy has been verified experimentally. It was found that the dielectric characterization of multiphase mixture system has great influence on the results, the complex refractive index mixture equation was used due to its lowest root-mean-square error value. In addition, the effect of moderate processing on microwave heating was examined in terms of porosity changes. However, nonuniform temperature distributions were found in the higher porous samples, especially when the porosity is greater than 0.81. Moreover, the developed model was coupled with the evaluation for gel properties and the results showed the significant effect of moderate crushing on the gel quality during the microwave heating process.
Assuntos
Calefação , Micro-Ondas , Porosidade , Temperatura Alta , Temperatura , GéisRESUMO
INTRODUCTION: Antifreeze peptides regulate the physiological functions of frozen cells and even their apoptosis; however, the mechanisms by which antifreeze peptides regulate these processes remain unclear, although the interactions between cell membranes and ice are well known to be important in this process. OBJECTIVES: Our study aims to investigate how antifreeze peptides regulate cell physiological functions during the freezing process. METHODS: We investigated the cryoprotective effect of rsfAFP on the physiological functions of S. thermophilus under freezing stress by measuring cellular metabolism activity, intracellular enzyme activity, cell membrane characterization, and cell apoptosis. The mechanism by which rsfAFP impacts S. thermophilus physiological functions under freezing stress was investigated using multispectral techniques and cryo-TEM. RESULTS: We show that a recombinant antifreeze peptide (rsfAFP) interacts with the extracellular capsular polysaccharides and peptidoglycan of Streptococcus thermophilus and ice to cover the outer layer of the membrane, forming a dense protective layer that regulates the molecular structure of extracellular ice crystals, which results in reduced extracellular membrane damage, depressed apoptosis and increased intracellular metabolic activity. This interaction mechanism was indicated by the fact that S. thermophilus better maintained its permeability barrier, membrane fluidity, membrane structural integrity, and cytoplasmic membrane potential during freezing stress with rsfAFP treatment. CONCLUSION: These results provide new insights into the mechanism by which rsfAFP regulates frozen cellphysiological functionsand apoptosis under freezing stress.
Assuntos
Gelo , Streptococcus thermophilus , Congelamento , Streptococcus thermophilus/metabolismo , Crioprotetores/farmacologia , Crioprotetores/química , Crioprotetores/metabolismo , Proteínas Anticongelantes/química , Proteínas Anticongelantes/metabolismo , Proteínas Anticongelantes/farmacologiaRESUMO
In this study, changes in the physical, structural, and assembly characteristics of silver carp myofibrillar proteins (MPs) at different ionic strength (I) values were investigated. Moreover, the differential proteomic profile of soluble MPs was analyzed using 4D proteomics based on timsTOF Pro mass spectrometry. Solubility of MPs significantly increased at high I (>0.3), and the increase in I enhanced the apparent viscosity, fluorescence intensity, surface hydrophobicity, and α-helix content of MPs solution. Particle size and sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns also supported the solubility profiles. Transmission electron microscopy and atomic force microscopy observations revealed the morphological assembly and disassembly of MPs under different I conditions. Finally, proteomic analysis revealed the evolution law of salt-induced solubilization of MPs and the critical molecular characteristics in different I environments. The number of differentially abundant proteins (DAPs) decreased with the increase of I, and most DAPs related to the muscle filament sliding, contraction and assembly, actinin binding, and actin filament binding. The soluble abundance of myosin and some structural proteins was dependent on I, and structural proteins in the Z-disk and M-band might contribute to the solubilization of myosin. Our findings provide insightful information about the impact of common I on the solubility pattern of MPs from freshwater fish.
Assuntos
Carpas , Proteômica , Animais , Eletroforese em Gel de Poliacrilamida , Água Doce , Espectrometria de MassasRESUMO
This study targeted the sustainable utilization of chitin and chitosan from crayfish shell waste, and further depolymerization of the recovered products in one step through synergy between microwaves and graphene oxide, aiming for the monosaccharides, 5-hydroxymethylfurfural and other high-value products. The results indicated that graphene oxide was more effective than graphene in enhancing the microwave absorption properties of the system, which is contrary to the parameters of their dielectric properties. The heating rate was increased by 0.37 K/s and 0.26 K/s when graphene oxide was introduced into the chitin and chitosan depolymerization systems, respectively, at a microwave power of 5 W/g. The mechanism underlying the impact of graphene oxide on chitin and chitosan under a microwave field was proposed by analyzing the variations in the depolymerization products of chitin and chitosan systems under different reaction conditions, including holding time, catalyst content, solvent content, and reaction temperature. Furthermore, the recovered graphene oxide exhibited delamination upon redispersion in water, which was not observed in the initial samples. The infrared spectra and scanning electron microscopy results suggest that the catalytic reaction is associated with oxygen-containing functional groups. This study demonstrated the synergistic effect of microwaves and graphene oxide on the depolymerization of chitin and chitosan, and the ability to achieve rapid one-step depolymerization in an acid/alkali-free solvent, which provides a green and promising development for the degradation of carbohydrate macromolecules in crustacean solid waste.
RESUMO
Freezing technology is important for storage of animal products such as surimi. However, mechanical damage caused by ice crystals would lead to quality deterioration. This study aims to investigate the protective effect of antifreeze peptides (AFPs) on the quality of surimi during freezing storage and its possible mechanism. We found that AFPs exhibited a strong inhibition of ice crystal recrystallization, and the molecular weight ranged from 180 to 3000 Da. AFPs can prevent the degeneration of myofibrillar protein by reducing the loss of Ca2+-ATPase activity, slowing oxidation of sulfhydryl groups to disulfide bonds, and maintaining surface hydrophobicity and solubility of myofibrillar protein. Moreover, AFPs can reduce the influence of freezing stress on water mobility, thereby protecting the surimi from losing immobilized water and bound water during frozen storage. These findings indicate that AFPs could potentially serve as a food ingredient with antifreeze functional for the storage of surimi products.
Assuntos
Proteínas Anticongelantes , Crioprotetores , Animais , Congelamento , Gelo , Produtos da Carne , Oxirredução , ÁguaRESUMO
Foodborne hydrolyzed antifreeze peptides have been widely used in the food industry and the biomedical field. However, the components of hydrolyzed peptides are complex and the molecular mechanism remains unclear. This study focused on identification and mechanism analysis of novel antifreeze peptides from Takifugu obscurus skin by traditional methods and computer-assisted techniques. Results showed that three peptides (EGPRAGGAPG, GDAGPSGPAGPTG, and GEAGPAGPAG) possessed cryoprotection via reducing the freezing point and inhibiting ice crystal growth. Molecular docking confirmed that the cryoprotective property was related to peptide structure, especially α-helix, and hydrogen bond sites. Moreover, the antifreeze peptides were double-faces, which controlled ice crystals while affecting the arrangement of surrounding water molecules, thus exhibiting a strong antifreeze activity. This investigation deepens the comprehension of the mechanism of antifreeze peptides at molecular scale, and the novel efficient antifreeze peptides can be developed in antifreeze materials design and applied in food industry.
Assuntos
Gelo , Takifugu , Animais , Cristalização , Simulação de Acoplamento Molecular , Congelamento , Proteínas Anticongelantes/química , Peptídeos/químicaRESUMO
The objective of this work was to investigate the cryoprotective effects of antifreeze peptides obtained from silver carp scales (ScAFPs) on the freeze-thaw stability of surimi, and to explore the action mechanisms of ScAFPs on frozen surimi. The comprehensive analysis of ice crystal size, myofibril protein oxidation, water retention, surimi gel properties, and rheological properties of surimi after different freeze-thaw cycles were investigated. Results showed that frozen surimi treated with ScAFPs exhibited a higher Ca2+-ATPase activity, salt-soluble protein concentration and sulfhydryl group content, while lower surface hydrophobicity, carbonyl content and disulfide bond content. Moreover, the gel properties and water holding capacity of surimi and surimi gel were improved significantly by regulating the size of ice crystals during freeze-thaw process. These findings indicate that ScAFPs could serviced as a new food ingredient with anti-freezing function for frozen products.
Assuntos
Carpas , Animais , Proteínas Anticongelantes , Crioprotetores/química , Crioprotetores/farmacologia , Gelo , Compostos de SulfidrilaRESUMO
Cryogenic machining is one of the most commonly used techniques for processing and preserving in food industry, and traditional antifreeze agents cannot regulate the mechanical stress damage caused by ice crystals formed during recrystallization or thawing. In this study, we successfully developed an express system of a novel recombinant snow flea antifreeze peptide (rsfAFP), which has significant ice recrystallization inhibition ability, thermal hysteresis activity and alters ice nucleation, thus regulating extracellular ice crystal morphology and recrystallization. We showed that rsfAFP improved the survival rate, acid-producing ability, freezing stability, and cellular metabolism activity of Streptococcus thermophilus. We further showed that rsfAFP interacts with the membrane and ice crystals to cover the outer layer of cells, forming a dense protective layer that maintains the physiological functions of S. thermophilus under freezing stress. These findings provide the scientific basis for using rsfAFP as an effective antifreeze agent for lactic acid bacteria cryopreservation or other frozen food.
RESUMO
Soybean protein pastes were preheated for different times (20, 25 and 30 min) with l-cysteine to improve the printability and self-gelation properties and to explore the relationship between the degree of denaturation and the feasibility of microwave 3D printing. As the pre-denaturation degree increased, ordered secondary structures in proteins gradually decreased, and tertiary structures unfolded. Soybean protein printability, moulding quality increased, and soybean protein, which is not suitable for printing in its natural state, achieved self-gelling after 3D printing. Soybean protein pastes preheated for 25 min with l-cysteine achieved a complete hollow sphere structure compared to other formulations, while pastes preheated for 30 min formed a coarser structure, and blockage occurred during printing. The covalent bond of ε- (γ-glutamine) formed by the synergistic effect of transglutaminase (TGase) and microwaves was the main force driving the gel network structure formation. The most suitable pre-denaturation degree of soybean protein was quantitatively characterized as 57 %.