Effects of high hydrostatic pressure treatment on allergenicity and structural properties of soybean protein isolate for infant formula

The objective of this study is to investigate the influences of HHP treatment on the allergenic properties of SPI for infant formula. The processing parameters, including HHP pressure and duration time, could significantly influence the allergenicity reducing efficiency. At 300 MPa and 15 min, the allergenicity decreased 48.6%, compared to the native SPI. In the ranges of 200-300 MPa and 5-15 min, the free SH content and hydrophobicity of SPI significantly increased. Meanwhile, at the levels above 300 MPa and 15 min, the two interactions progressively decreased. Whatever HHP pressure and time, the maximum emission wavelength indicated blueshifts. At 300 MPa and 15 min, there was an 11.5-fold increase in fluorescence intensity and the maximum emission wavelength shifted from 516 to 466 nm. After HHP treatment, the helix1 and turns content, significantly increased and the strand1 and unordered content considerably decreased; whereas the amount of the helix2 and strand2 did not indicate any obvious change. The average length of helices significantly increased, while the helices (per 100 residues) did not strikingly change after HHP modification. However, both the strand (per 100 residues) and the average length of strands clearly decreased. Some documents indicate that the epitopes of SPI allergens could be closely related to the secondary structure of α-helix and β-sheet. These interactions and secondary structure results can provide direct evidence, or explanation, for HHP-induced modification of soy proteins, which could alter the allergenicity of SPI and enhance the security of SPI for cow milk allergic babies.     

超高压处理对大米蛋白功能特性及结构的影响

以不同压力（200、400、600 MPa）对大米进行超高压处理。研究了超高压处理对大米中谷蛋白功能特性以及清蛋白、球蛋白和谷蛋白结构的影响。结果表明:超高压处理后大米蛋白的功能特性和二级结构均发生变化,不同压力影响效果不同。200 MPa时蛋白质的溶解性、持水性和乳化性提高,持油性降低;400 MPa时持水性和乳化性降低,持油性提高,溶解性升高不明显;600 MPa时溶解性、持水性、持油性和乳化性均降低。超高压处理后清蛋白、球蛋白和谷蛋白的二级结构发生改变,β-折叠结构含量降低,无序结构增多。相关性分析结果表明压力、功能特性和二级结构三者之间存在相关性。      

Effect of high hydrostatic pressure on the structure,physicochemical and functional properties of protein isolates from cumin (Cuminum cyminum) seeds

The effect of high hydrostatic pressure (HHP) treatment on the structure, physicochemical and functional properties of cumin protein isolate (CPI) was investigated. More aggregates, pores, irregular conformations and bigger particle size were observed for HHP-treated CPI. HHP resulted in an increase in α-helix, a decrease in β-strand and fluorescence intensity of CPI. Surface hydrophobicity (H_o) of CPI significantly increased after HHP treatment, from 343.35 for native CPI to 906.22 at 600 MPa (P < 0.05). HHP treatment at 200 MPa reduced zeta-potential and solubility of CPI, while had little effect at 400 and 600 MPa. Emulsifying activity and stability of CPI decreased after HHP treatment, of which droplet size of emulsions significantly increased (P < 0.05). HHP-treated CPI could form heat-induced gelation at lower temperature (68.5 °C) and improved storage modulus (G′) comparing to native one (80.6 °C), suggesting that CPI might be potential protein resources as gelation substitute in food system.     

Effects of high hydrostatic pressure on Eimeria acervulina pathogenicity,immunogenicity and structural integrity

Eimeria acervulina is a protozoan parasite that can cause intestinal lesions and reduced weight gain in chickens. E. acervulina oocysts were treated by high hydrostatic pressure and evaluated for pathogenicity, immunogenicity, and structural integrity. Pressure treatment of E. acervulina oocysts at 550 MPa for 2 min at 4, 20 or 40 °C rendered the parasites nonpathogenic to chickens. Pressure treatment at 40 °C also prevented fecal shedding of oocysts. Upon challenge with non-pressurized E. acervulina oocysts, partial immunity was observed with a reduction in lesion severity in chickens that had been inoculated with pressure-treated oocysts. No changes to the fragility and permeability of the oocyst wall or excystation of sporocysts were observed as a result of pressure treatment. Light and scanning electron microscopy revealed no changes to the whole oocyst or sporocysts. Recovery and the morphology of excysted sporozoites were altered by pressure treatment. These results suggest that pressure affects sporozoite integrity.Industrial relevanceHigh-hydrostatic pressure processing has been shown to inactivate various microorganisms and is utilized commercially for enhanced food safety and quality. Some pathogenic microorganisms have been inactivated by HPP yet retain immunogenic properties suggesting potential application for vaccine development. Eimeria acervulina is a poultry pathogen for which new vaccines are sought. E. acervulina is also closely related to Cyclospora cayetanensis, a foodborne human pathogen. HPP was explored for effect on E. acervulina for potential vaccine development for chickens and for insight on HPP effects on parasites for enhanced safety of human foods.     

Effects of high hydrostatic pressure on membrane proteins of Salmonella typhimurium

Salmonella typhimurium is a leading cause of foodborne diseases. Today high hydrostatic pressure treatments are considered as alternative methods of preservation. To select optimal conditions of treatment, we have to characterize the cell targets of pressure. In this study the action of pressure on the bacterial membrane proteins is analysed. The total membrane extract is obtained by lysis of cells separated by equilibrium density gradient centrifugation. Protein content is analysed by electrophoresis SDS-PAGE and visualised by silver stain. Electrophoretic profiles reveal the presence of three major outer membrane proteins and 12 minor proteins in control bacteria outer membranes. Outer membrane protein content is drastically modified after treatments. In some cases, except for the major proteins OmpA and LamB, other outer membrane proteins seem to totally disappear. LamB is more resistant to hyperbaric exposure when the pH of the media is acidic. This behaviour could be explained by a different conformation adopted by the LamB protein depending on the extracellular pH. This work allows us to define membrane proteins as a target of high hydrostatic pressure treatments. Knowledge of the behaviour of these bacterial membrane proteins subjected to pressure under different conditions (pH, temperature, a(w)...) could allow an increase in the efficiency of treatments.     

Combined effects of limited enzymatic hydrolysis and high hydrostatic pressure on the structural and emulsifying properties of rice proteins

The combined effects of limited enzymatic hydrolysis and high hydrostatic pressure (HHP) treatment on the structural and emulsifying properties of rice proteins (RPs) were investigated. Alcalase exhibited higher hydrolysis efficiency than papain. Through alcalase-catalyzed hydrolysis and HHP treatment, emulsifying activity index (EAI) and emulsifying stability index (ESI) of RPs were improved from 14.58 m²/g and 22.54 min to 29.93 m²/g and 43.35 min, respectively. The content of random coil in RPs increased, while the content of α-helix decreased. HHP at 300 MPa led to the highest surface hydrophobicity (H₀) and fluorescence intensity. The enzymatic hydrolysis-HHP (300 MPa) modified RPs could form an oil-in-water emulsion with a d_4,3 of 0.347 nm, ζ-potential of −36.4 mV, and creaming index of 10.5% after 7 days storage. This work sheds light on employing limited enzymatic hydrolysis and HHP to modify RPs for better application in emulsion-based food products.     

超高压处理对小米粉理化特性的影响研究

对米水比例为1∶1、1∶2(w/w)的小米在600 MPa下分别处理15 min、30 min,探讨不同处理条件对小米粉理化特性的影响。结果表明：与空白组相比,超高压对4组不同样品小米粉颗粒形貌、粒径和晶体特性均有影响。全粉中淀粉颗粒形貌由分散的不规则球体变为与其他物质络合粘结成块结构,颗粒平均粒径显著降低,颗粒整体缩小,晶体结构由天然A型转变为B型,米水比为1∶2时对微观结构影响尤为显著。动态流变表明超高压处理后小米粉糊G’和tanδ均高于原粉,G’’均低于原粉,表明高压处理可提高小米淀粉弹性和黏性,该技术可作为有效的物理改性方法改善小米粉的物理特性。     

Effects of high hydrostatic pressure on the conformational structure and the functional properties of bovine serum albumin

Non-thermal technologies, such as High Hydrostatic Pressure (HHP), are able to induce extensive changes in the structure of biological macromolecules, namely proteins. HHP treatments disrupt the electrostatic interactions, which stabilize the quaternary and the tertiary structure of the proteins, and activate the reactions of sulfhydryl-disulfide bond exchange. These structural changes result in the dissociation and refolding of proteins during HHP treatments, and consequently in the modification of protein functional properties, namely physicochemical properties (solubility, binding and surfactant properties, water and oil absorption capacity, emulsifying and foaming properties). The technological behavior of the proteins in food preparation, processing, storage, as well as their contribution to determine quality perception of foods mainly depends on these functional properties.This work aims at investigating the effects of HHP treatments on the conformational (quaternary, tertiary and secondary) structure and the functional properties of a globular water soluble protein, the Bovine Serum Albumin (BSA). BSA (50–100 mg/mL) solutions in Sodium Phosphate Buffer were processed at different pressure levels (100–500 MPa) and treatment times (15, 25 min). BSA unfolding and refolding were analyzed in terms of free sulfhydryl (SH) groups, changes of secondary structure, foaming and emulsifying properties.Analyzing the experimental data it can be concluded that the unfolding of BSA samples with a concentration of 50 mg/mL occurred in the pressure range between 100 and 400 MPa. In fact an increased number of the free SH groups as well as an improved foaming and emulsifying ability were detected in the treated samples. Pressure levels above 400 MPa promoted the interactions between adjacent polypeptide chains and the formation of soluble high molecular mass aggregates. The concentration of the protein in the samples, also, controlled the occurrence of unfolding and aggregation. Extensive changes in BSA secondary structure were observed at pressure level above 300 MPa, for longer processing times and higher protein concentrations. In these processing conditions β-sheet aggregates were likely to replace the initial α-helixes.Industrial relevanceThe paper consists in the study of the Effects of High Hydrostatic Pressure processing (HHP) on the conformational structure and the functional properties of Bovine Serum Albumin.he work proposes an innovative technology for Food Industries that can be widely used for food conservation and to induce protein modifications in the same time. For this reason the technology represents a good tool for the production of hypoallergenic compounds especially in the field of dairy products and infant formula companies.     

Tailoring structure and technological properties of plant proteins using high hydrostatic pressure

The demand for proteins is rising and alternatives to meat proteins are necessary since animal husbandry is expensive and intensive to the environment. Plant proteins appear as an alternative; however, their techno-functional properties need improvement. High-pressure processing (HPP) is a non-thermal technology that has several applications including the modification of proteins. The application of pressure allows modifying proteins' structure hence allowing to change several of their properties, such as hydration, hydrophobicity, and hydrophilicity. These properties may influence the solubility of proteins and their ability to stabilize emulsions or foams, create aggregates or gels, and their general role in stability and texture of food commodities. Commonly HPP decreases the proteins' solubility yet increasing their surface hydrophobicity exposing sulfhydryl groups, which promotes aggregation or gelation or enhance their ability to stabilize emulsions/foams. However, these effects are not verifiable for all the proteins and are immensely dependent on the type and concentration of the protein, environmental conditions (pH, ionic strength, and co-solutes), and HPP conditions. This review collects and critically discusses the available information on how HPP affects the structure of plant proteins and how their techno-functional properties can be tailored using this approach.     

超高压对食品中微生物的影响

超高压是一种新型食品加工技术,已广泛应用于食品的非热加工。在超高压条件下微生物的细胞壁、细胞膜被破坏,引起细胞形态结构的改变;微生物细胞内的结构蛋白、酶等在超高压条件下被钝化,导致微生物正常的代谢功能和增殖能力被破坏;在超高压条件下微生物的蛋白组和基因组也产生了一定的变化,许多与抗逆有关的蛋白质和基因表达上调。     

Effect of high hydrostatic pressure on mortality and allergenicity of Anisakis simplex L3 and on muscle properties of infested hake

BACKGROUND: High pressure (HP) ranging from 100 to 350 MPa (1–15 min) was applied to Anisakis simplex larvae and parasitised hake (Merluccius merluccius) muscle. The aim of the study was to kill the larvae to prevent human anisakidosis, to evaluate the effect on A. simplex allergens and to minimally alter fish muscle quality. RESULTS: The larvae were killed at pressures ≥ 200 MPa and times ≥ 1 min, producing alterations in the larva body and ruptures in the cuticle when observed by scanning electron microscopy. Nevertheless, Ani s 4 and A. simplex crude antigens were recognised by immunoblotting and immunohistochemistry at all HPs assayed. Small changes in colour and texture were observed in fish muscle under all pressure/time conditions. Major changes were observed visually at 300 MPa, where the muscle appeared as slightly cooked. Apparent viscosity of muscle homogenates decreased significantly at longer times or higher applied pressure. No changes were detected at 200 MPa in the electrophoretic pattern of proteins treated with or without β‐mercaptoethanol, suggesting that disulfide bonds were not formed. CONCLUSION: Application of HP at 200 MPa for up to 5 min would kill A. simplex larvae, avoiding infestation of the consumer and causing small changes in the hake muscle perceived sensorially. However, HP‐treated A. simplex‐parasitised fish would still be a potential hazard for consumers allergic to the larvae. Copyright © 2009 Society of Chemical Industry     

高静压处理对魔芋葡甘聚糖/大豆分离蛋白复合溶胶特性的影响

为考察高静压对多糖-蛋白质复合体系功能特性的影响,以魔芋葡甘聚糖和大豆分离蛋白为原料,研究不同压力、不同时间下高静压处理对两者复合溶胶的乳化活性、乳化稳定性、黏度特性以及微观结构的影响。研究结果表明,在400 MPa压力下经不同的处理时间,复合溶胶的功能性质均有显著性提高,其中乳化活性、乳化稳定性在处理10~15 min时达到最佳,与空白组相比分别提高了5.6%~6.2%和2.5%~2.7%,而黏度则在400 MPa/15 min时达最高值,比空白组提高了145.3%。同时扫描电镜分析得出,适当高静压处理可使多糖和蛋白质复合溶胶体系形成更加均匀致密的三维网络结构,二者间相互作用增强。     

Effects of high hydrostatic pressure on physicochemical and functional properties of walnut (Juglans regia L.) protein isolate

BACKGROUND: Walnut (Juglans regia L.) is a good source of protein that has potential application in new product formation and fortification. The main objectives of this study were to investigate the effects of high hydrostatic pressure (HHP) treatment (300–600 MPa 20 min) on physicochemical and functional properties of walnut protein isolate (WPI) using various analytical techniques at room temperature. RESULTS: The results showed significant modification of solubility, free sulfhydryl content and surface hydrophobicity with increased levels of HHP treatment, indicating partial denaturation and aggregation of proteins. Differential scanning calorimetry and fluorescence spectrum analyses demonstrated that HHP treatment resulted in gradual unfolding of protein structure. Emulsifying activity index was significantly (P < 0.05) increased after HHP treatment at 400 MPa, but significantly decreased (P < 0.05) relative to the untreated WPI with further increase in pressure. HHP treatment at 300–600 MPa significantly decreased emulsion stability index. Additionally, HHP‐treated walnut proteins showed better foaming properties and in vitro digestibility. CONCLUSION: These results suggest that HHP treatment could be applied to modify the properties of walnut proteins by appropriate of pressure levels, which will help in using walnut protein as a potential food ingredient. © 2012 Society of Chemical Industry     

Physical properties of surimi sausages subjected to high hydrostatic pressure treatment

Food Science and Biotechnology - We aimed to investigate the effect of high pressure treatment (HPT) on the physical properties of surimi sausages. For protein gelation, high hydrostatic pressure...     

高静压对水产品加工及其致敏性影响的研究进展

水产品过敏已成为当今世界性的重大卫生和食品安全问题之一。高静压作为一种新的非热加工技术, 在水产品中具有潜在的应用前景。本文介绍了高静压加工的基本原理、高静压加工在水产品中的应用、水产品过敏的流行性, 重点阐述了水产品过敏原蛋白类型及特性、高静压对过敏原蛋白结构及其致敏性影响的研究概况, 提出了今后高静压水产品加工和过敏原蛋白研究的方向和建议。     

高静压加工对山竹汁微生物及品质的影响

利用高静压(high hydrostatic pressure,HHP)技术对山竹果汁中的微生物和果汁品质进行研究。结果表明:经400 MPa,10 min和500 MPa,5 min的HHP处理后,山竹汁中的自然菌群全部被杀灭,而山竹汁的颜色、糖度、酸度等理化指标,以及其中的VC、总酚含量和抗氧化活性等营养品质,未发生显著的变化(P>0.05)。     

Effect of high pressure processing on structural and functional properties of canned aquafaba

Food Science and Biotechnology - Aquafaba is chickpea cooking water. It has great functional properties since it consists of starch and protein. High pressure processing (HPP) is proven to modify...     

Differences in properties of myofibrillar proteins from bovine semitendinosus muscle after hydrostatic pressure or heat treatment

Hydrostatic pressure (HP) and heat treatments of myofibrillar proteins have both been shown to induce protein denaturation, but different gel formation properties result from these treatments. To characterise differences in the properties of proteins resulting from HP or heat treatment, Ca‐ and Mg‐ATPase activities (ATP, adenosine triphosphate) and protein solubility in 0.1 and 0.6 mol L^?1 KCl buffers (pH 7) were evaluated in this study. The inactivation rate of Ca‐ATPase of myofibrillar proteins (Mf) induced by HP was slower than that of Mg‐ATPase at each of the tested pressures. However, the inactivation rate of Ca‐ATPase induced by heating was faster than that of Mg‐ATPase at each of the tested temperatures. The level of soluble proteins in Mf suspension induced by HP in 0.1 mol L^?1 KCl buffer increased with increasing pressure up to 400 MPa and then decreased slightly at 500 MPa. However, the level of soluble proteins in Mf suspension induced by heat treatment in 0.1 mol L^?1 KCl buffer increased with increasing temperature up to 55°C. According to the results of sodium dodecyl sulfate polyacrylamide gel electrophoresis, the levels of soluble myosin heavy chain and actin in Mf suspension induced by HP in 0.6 mol L^?1 KCl buffer decreased simultaneously at pressures higher than 300 MPa. The level of soluble MHC in 0.6 mol L^?1 KCl buffer decreased gradually with increasing temperature, but there were no changes in the level of soluble actin in 0.6 mol L^?1 KCl buffer with increasing temperature up to 50°C. These results showed that the mechanism of HP‐induced protein denaturation was different from the mechanism underlying heat‐induced protein denaturation. Copyright © 2006 Society of Chemical Industry     

Decontamination of seeds for seed sprout production by high hydrostatic pressure

Garden cress, sesame, radish, and mustard seeds immersed in water were treated with high pressure (250, 300, 350, and 400 MPa) for 15 min at 20 degrees C. After treatment, percentages of seeds germinating on water agar were recorded for up to 11 days. Of the seeds tested, radish seeds were found to be the most pressure sensitive, with seeds treated at 250 MPa reaching 100% germination 9 days later than untreated control seeds did. Garden cress seeds, on the other hand, were the most pressure resistant, with seeds treated at 250 MPa reaching 100% germination 1 day later than untreated control seeds did. Garden cress sprouts from seeds treated at 250 and 300 MPa also took about 1 day longer to reach average sprout length than sprouts from untreated control seeds did, indicating that sprout growth was not retarded once germination had occurred. Garden cress seeds were inoculated with suspensions of seven different bacteria (10(7) CFU/ml) and processed with high pressure. Treatment at 300 MPa (15 min, 20 degrees C) resulted in 6-log reductions of Salmonella Typhimurium, Escherichia coli MG1655, and Listeria innocua, > 4-log reductions of Shigella flexneri and pressure-resistant E. coli LMM1010, and a 2-log reduction of Staphylococcus aureus. Enterococcus faecalis was virtually not inactivated. For suspensions of the gram-positive bacteria, similar levels of inactivation in water in the absence of garden cress seeds were found, but the inactivation of E. coil LMM1010 and S. flexneri in water in the absence of garden cress seeds was significantly less extensive. These data suggest that garden cress seeds contain a component that acts synergistically with high hydrostatic pressure against gram-negative bacteria.