Dynamic interfacial rheology as a tool for the characterization of whey protein isolates gelation at the oil-water interface.

Heat-induced interfacial aggregation of a whey protein isolate (WPI), previously adsorbed at the oil-water interface, was studied by interfacial dynamic characteristics coupled with microscopic observation and image analysis of the drop after heat treatment. The experiments were carried out at temperatures ranging from 20 to 80 degrees C with different thermal regimes. During the heating period, competition exists between the effect of temperature on the film fluidity and the increase in mechanical properties associated with the interfacial gelation process. During the isothermal treatment, the surface dilational modulus, E, increases, and the phase angle, delta, decreases with time to a plateau value. The frequency dependence of E and delta is characteristic of viscoelastic films with increasing delta and decreasing E at lower frequencies. The effects of heat treatment depend on the conditions at which the gelation process takes place. Microscopic observation of gelled films gives complementary information on the effect of heat treatment on WPI adsorbed films.     

Identification of the wheat seed protein CM3 as a highly active emulsifier using a novel functional screen

Lyophilized albumin protein fractions were prepared from flour of four varieties of wheat: Triticum aestivum cvs. Mercia and Riband, Triticum aestivum var. spelta, and Triticum turgidum var. durum (Kamut). The dry powders were redissolved in sodium phosphate buffers at pH 3.0, 6.5, or 8.0 and at ionic strengths of 0.1 or 1.0 M to a concentration of 0.1% (w/v). Emulsions formed by sonication of protein solutions with n-hexadecane were aged at room temperature and separated into aqueous, interstitial, and interfacial phases. The distinct emulsion components were lyophilized and analyzed by RP-HPLC. A protein was observed to be preferentially located in the interfacial component and subsequently purified from a total albumin fraction and identified by N-terminal sequencing as CM3, an alpha-amylase inhibitor subunit. Measurement of the equilibrium surface tension of CM3 as a function of protein concentration demonstrated that it was at least as active as bovine beta-lactoglobulin, an established protein emulsifier. Furthermore, measurement of the surface dilational elastic modulus at an air/water interface demonstrated the formation of a viscoelastic film, while fluorescence and FT-IR spectroscopic measurements on adsorbed and nonadsorbed CM3 suggest that the secondary structure is essentially unchanged upon adsorption to an oil/water interface. It is concluded that functional screening is a valid approach to identify novel protein emulsifiers in complex mixtures.     

Effect of processing on the displacement of whey proteins: applying the orogenic model to a real system

Atomic force microscopy (AFM) has been used to investigate the displacement of a commercial whey protein system and the behavior as compared to that of beta-lactoglobulin (Mackie, A. R.; Gunning, A. P.; Wilde, P. J.; Morris, V. J. Orogenic displacement of protein from the air-water interface by competitive adsorption. J. Colloid Interface Sci. 1999, 210, 157-166). The whey protein isolate (WPI) was displaced from an air-water interface by the surfactants Tween 20 and Tween 60. Displacement data obtained were compared with data obtained for pure beta-lactoglobulin and have shown that WPI was more resistant to displacement from the air-water interface than native beta-lactoglobulin. This was related to the greater surface elasticity of WPI at higher surface stresses. In the presence of Tween 20, WPI was observed to remain on the interface at surface pressures up to 8 mN/m greater than the surface pressure at which complete displacement of beta-lactoglobulin was observed. Displacement of WPI and beta-lactoglobulin films by the surfactant Tween 60 showed similar results. However, because of the lower surface activity of Tween 60, it was not possible to reach surface tension values similar to those obtained for Tween 20. Despite the lower surface activity of Tween 60, WPI was still observed to be present at the interface at surface pressure values greater than those by which beta-lactoglobulin had been completely displaced.     

Effect of sucrose on functional properties of soy globulins: adsorption and foam characteristics

In this contribution, we have analyzed the effect of sucrose on dynamic interfacial (dynamic surface pressure and surface dilatational properties) and foaming (foam capacity and foam stability) characteristics of soy globulins (7S and 11S). The protein (at 1 x 10(-3), 1 x 10(-2), 0.1, and 1 wt %) and sucrose (at 0, 0.25, 0.5, and 1.0 M) concentrations in aqueous solution and the pH (at 5 and 7), and ionic strength (at 0.05 and 0.5 M) were analyzed as variables. The temperature was maintained constant at 20 degrees C. We have observed the following. (i) The dynamics of adsorption (presence of a lag period, diffusion, and penetration at the air-water interface) of soy globulins depend on the peculiar molecular features of proteins (7S or 11S soy globulin) and the level of association/dissociation of these proteins by varying the pH and ionic strength, as well as the effect of sucrose in the aqueous phase on the unfolding of the protein. The rate of adsorption increases with the protein concentration in solution, at pH 7 compared to pH 5, at high ionic strength, and in the absence of sucrose. (ii) The surface dilatational properties reflect the fact that soy globulin adsorbed films exhibit viscoelastic behavior. The surface dilatational modulus increases at pH 7 compared to pH 5, but decreases with the addition of sucrose into the aqueous phase. (iii) The rate of adsorption and surface dilatational properties (surface dilatational modulus and phase angle) during adsorption at the air-water interface play an important role in the formation of foams generated from aqueous solutions of soy globulins. (iv) The increased interfacial adsorption (at high surface pressures) and the combined effects of interfacial adsorption and interfacial interactions between adsorbed soy globulin molecules (at high surface dilatational modulus) can explain the higher stability of the foam, with few exceptions.     

Preparation of whey protein hydrolysates using a single- and two-stage enzymatic membrane reactor and their immunological and antioxidant properties: characterization by multivariate data analysis

An initial 5% (w/v), followed thereafter with replacement aliquots of 3% (w/v), whey protein isolate (WPI) (ca. 86.98% Kjeldahl N x 6.38), was hydrolyzed using Protease N Amano G (IUB 3.4.24.28, Bacillus subtilis) in an enzymatic membrane reactor (EMR) fitted with either a 10 or 3 kDa nominal molecular weight cutoff (NMWCO) tangential flow filter (TFF) membrane. The hydrolysates were desalted by adsorption onto a styrene-based macroporous adsorption resin (MAR) and washed with deionized water to remove the alkali, and the peptides were desorbed with 25, 50, and 95% (v/v) ethyl alcohol. The desalted hydrolysates were analyzed for antibody binding, free radical scavenging, and molecular mass analysis as well as total and free amino acids (FAA). For the first time a quantity called IC50, the concentration of peptides causing 50% inhibition of the available antibody, is introduced to quantify inhibition enzyme-linked immunosorbent assay (ELISA) properties. Principal component analysis (PCA) was used for data reduction. The hydrolysate molecular mass provided the most prominent influence (PC1 = 57.35%), followed by inhibition ELISA (PC2 = 18.90%) and the antioxidant properties (PC3 = 10.43%). Ash was significantly reduced in the desalted fractions; the protein adsorption recoveries were high, whereas desorption with alcohol was prominently influenced by the hydrophobic/ hydrophilic amino acid balance. After hydrolysis, some hydrolysates showed increased ELISA reactivity compared with the native WPI.     

Formulation engineering can improve the interfacial and foaming properties of soy globulins

In this contribution, we have analyzed the effect of different strategies, such as change of pH (5 or 7) or ionic strength (at 0.05 and 0.5 M), and addition of sucrose (at 1 M) and Tween 20 (at 1 x 10(-4) M) on interfacial characteristics (adsorption, structure, dynamics of adsorption, and surface dilatational properties) and foam properties (foam capacity and stability) of soy globulins (7S and 11S at 0.1 wt %). We have observed that (1) the adsorption (presence of a lag period, diffusion, and penetration at the air-water interface) of soy globulins depends on the modification in the 11S/7S ratio and on the level of association/dissociation of these proteins by varying the pH and ionic strength (I), the effect of sucrose on the unfolding of the protein, and the competitive adsorption between protein and Tween 20 in the aqueous phase. The rate of adsorption increases at pH 7, at high ionic strength, and in the presence of sucrose. (2) The surface dilatational properties reflect the fact that soy globulin adsorbed films exhibit viscoelastic behavior but do not have the capacity to form a gel-like elastic film. The surface dilatational modulus increases at pH 7 and at high ionic strength but decreases with the addition of sucrose or Tween 20 into the aqueous phase. (3) The rate of adsorption and surface dilatational properties (surface dilatational modulus and phase angle) during adsorption at the air-water interface plays an important role in the formation of foams generated from aqueous solutions of soy globulins. However, the dynamic surface pressure and dilatational modulus are not enough to explain the stability of the foam.     

Stability of β-carotene in protein-stabilized oil-in-water delivery systems

Inclusion of liposoluble bioactive compounds in fortified foods represents a complex challenge due to the labile nature of such compounds and the instability of oil-in-water emulsion-based delivery systems. In the present study, dispersions prepared with 10% (w/w) sunflower oil (SO) or hydrogenated palm kernel oil (HPKO) containing 0.05% (w/w) β-carotene were stabilized by various concentrations of whey protein isolate (WPI) or sodium caseinate (NaCas) (0.1 to 2.0% w/w) in 30% (w/w) sucrose aqueous solutions. Physicochemical characterization of emulsions was done considering the particle size, the particle surface protein coverage, and the physical state of continuous and dispersed phases. Physical stability of the systems and their protection properties on β-carotene were compared. The lipid carrier type and interfacial structure were investigated as the two key factors which regulate the stability of labile lipophilic bioactive molecules in food model systems. Our results showed high β-carotene stability when O/W systems were stable (protein concentration ≥0.8% w/w.) A (partially) solid lipid carrier (HPKO) enhanced protection compared to the liquid carrier (SO) as the bioactive molecules were entrapped in isolated domains within the solid lattice and kept apart from reactive species in the surroundings. NaCas provided a better barrier than WPI due to the different amino acid composition and interface structure which significantly reduced β-carotene degradation rate.     

Adsorption and dilatational rheology of heat-treated soy protein at the oil-water interface: relationship to structural properties

We evaluated the influence of heat treatment on interfacial properties (adsorption at the oil-water interface and dilatational rheology of interfacial layers) of soy protein isolate. The related structural properties of protein affecting these interfacial behaviors, including protein unfolding and aggregation, surface hydrophobicity, and the state of sulfhydryl group, were also investigated. The structural and interfacial properties of soy protein depended strongly on heating temperature (90 and 120 °C). Heat treatment at 90 °C induced an increase in surface hydrophobicity due to partial unfolding of protein, accompanied by the formation of aggregates linked by disulfide bond, and lower surface pressure at long-term adsorption and similar dynamic interfacial rheology were observed as compared to native protein. Contrastingly, heat treatment at 120 °C led to a higher surface activity of the protein and rapid development of intermolecular interactions in the adsorbed layer, as evidenced by a faster increase of surface pressure and dilatational modulus. The interfacial behaviors of this heated protein may be mainly associated with more flexible conformation and high free sulfhydryl group, even if some exposed hydrophobic groups are involved in the formation of aggregates. These results would be useful to better understand the structure dependence of protein interfacial behaviors and to expand utilization of heat-treated protein in the formulation and production of emulsions.     

Polyphenol-beta-casein complexes at the air/water interface and in solution: effects of polyphenol structure

The interactions between proteins and plant polyphenols are responsible for astringency and haze formation in beverages and may participate in foam stabilization. The effect of phenolic compounds with different structures, namely, catechin (C), epicatechin (Ec), epigallocatechin (Egc), epicatechin gallate (EcG), and epigallocatechin gallate (EgcG), on the surface properties at the air/liquid interface of beta-casein, chosen as model protein, were monitored by tensiometry and ellipsometry. The formation of complexes in the bulk phase was measured by electrospray ionization mass spectrometry (ESI-MS). Adsorption of polyphenols from pure solution was not observed. Surface pressure, surface concentration, and dilational modulus of the protein adsorption layer were greatly modified in the presence of galloylated flavanol monomers (EcG and EgcG) but not of lower molecular weight polyphenols (<306 g/mol). The formation of polyphenol-protein aggregates in the bulk, as evidenced by ESI-MS and light scattering experiments, was related to the slowdown of protein adsorption.     

Interfacial and oil/water emulsions characterization of potato protein isolates

Interfacial and emulsifying properties of potato protein isolate (PPI) have been studied to evaluate its potential application to stabilize oil/water emulsions at two pH values (2 and 8). The amount, type, and solubility of proteins and the size of aggregates have been determined in aqueous dispersion. Air-water and oil-water interfacial properties (adsorption, spreading, and viscoelastic properties) have been determined as a function of concentration and pH using soluble phases of PPI. The behavior of PPI stabilized oil/water emulsions has been then analyzed by droplet size distribution measurements and interfacial concentration. PPI exhibits low solubility over a wide range of pH values, with the presence of submicrometer aggregates. The pH value exerts a negligible effect on interfacial tension (oil-water) or surface pressure (air-water) but displays very important differences in viscoelastic properties of the interfacial films formed between oil and water. In this sense, pH 8 provides a major elastic response at oil-water interfaces as compared to pH 2. In relation with this result, a much higher ability to produce fine and stable emulsions is noticed at pH 8 as compared to pH 2. Consequently, there is an evident relationship between the rheological properties of the oil-water interfacial films and the macroscopic emulsion behavior.     

Structural changes imposed on whey proteins by UV irradiation in a continuous UV light reactor

The objective of this study was to investigate the structural changes of whey proteins during exposure in a continuous-flow UV reactor. Varying UV irradiation dosages were obtained by controlling the flow rate and the mixing speed. Whey protein isolate (WPI) solutions at concentrations of 1% and 5% (w/v) were circulated at flow rates ranging from 30 to 800 mL·min(-1), and changes in physicochemical properties of the proteins were investigated. Intrinsic fluorescence spectra and surface hydrophobicity measurements suggested changes in the tertiary structure of the proteins with UV exposure. The UV treatment also increased the concentration of total and accessible thiol groups in 1% WPI solutions, while no change was measured in 5% WPI solutions. Size-exclusion chromatography demonstrated the formation of UV-induced aggregates and oxidation products (N-formylkynurenine and dityrosine) of aromatic amino acids. Furthermore, the UV-induced changes in protein conformation increased the susceptibility of whey proteins to pepsin hydrolysis.     

Limited enzymatic hydrolysis can improve the interfacial and foaming characteristics of beta-conglycinin

In this contribution, we have determined the effect of limited enzymatic hydrolysis on the interfacial (dynamics of adsorption and surface dilatational properties) and foaming (foam formation and stabilization) characteristics of a soy globulin (beta-conglycinin, fraction 7S). The degree of hydrolysis (DH = 0, 2, and 5%), the pH of the aqueous solution (pH = 5 and 7), and the protein concentration in solution (at 0.1, 0.5, and 1 wt %) were the variables studied. The temperature and the ionic strength were maintained constant at 20 degrees C and 0.05 M, respectively. The rate of adsorption and surface dilatational properties (surface dilatational modulus, E, and loss angle) of beta-conglycinin at the air-water interface depend on the pH and DH. The adsorption decreased drastically at pH 5.0, close to the isoelectric point of beta-conglycinin, because of the existence of a lag period and a low rate of diffusion. The interfacial characteristics of beta-conglycinin are much improved by enzymatic treatment, especially in the case of acidic aqueous solutions. Hydrolysates with a low DH have improved functional properties (mainly foaming capacity and foam stability), especially at pH values close to the isoelectric point (pI), because the protein is more difficult to convert into a film at fluid interfaces at pH approximately equal to pI.     

Interactions of high methoxyl pectin with whey proteins at oil/water interfaces at acid pH

The interactions between whey protein isolate (WPI) and high methoxyl pectin (HMP) at pH 3.5 were investigated in situ using ultrasound (US) and diffusing wave spectroscopy (DWS). HMP was added to 10% oil-in-water emulsions containing 1% WPI. At neutral pH, no protein-pectin interactions were observed as both molecules are negatively charged, while at pH 3.5 bridging flocculation occurred via electrostatic interactions. Four different stages were distinguished during the addition of HMP in WPI-stabilized emulsions at pH 3.5. At a concentration below a critical value, no interactions were observed. At concentrations >0.02% HMP, a change in the l factor indicated a change in the ordering of the emulsion droplets, influenced by long-range interactions. At higher concentrations (in the range between 0.04 and 0.06% HMP), attenuation showed significant changes in the surface of the oil droplets, changes which affected the droplet-droplet interactions. At pectin concentrations >0.05%, attenuation of sound and 1/l* decreased, while velocity of sound and particle size increased, as a result of bridging flocculation. These results demonstrated for the first time that methods such as US and DWS combined permit the observation of the early stages of the interactions between two biopolymers at the interface. This is significant in light of increasing efforts in engineering complex interfacial layers.     

Cross-linking and rheological changes of whey proteins treated with microbial transglutaminase

Modification of the functionality of whey proteins using microbial transglutaminase (TGase) has been the subject of recent studies. However, changes in rheological properties of whey proteins as affected by extensive cross-linking with TGase are not well studied. The factors affecting cross-linking of whey protein isolate (WPI) using both soluble and immobilized TGase were examined, and the rheological properties of the modified proteins were characterized. The enzyme was immobilized on aminopropyl glass beads (CPG-3000) by selective adsorption of the biotinylated enzyme on avidin that had been previously immobilized. WPI (4 and 8% w/w) in deionized water, pH 7.5, containing 10 mM dithiothreitol was cross-linked using enzyme/substrate ratios of 0.12-10 units of activity/g WPI. The reaction was carried out in a jacketed bioreactor for 8 h at 40 degrees C with continuous circulation. The gel point temperature of WPI solutions treated with 0.12 unit of immobilized TGase/g was slightly decreased, but the gel strength was unaffected. However, increasing the enzyme/substrate ratio resulted in extensive cross-linking of WPI that was manifested by increases in apparent viscosity and changes in the gelation properties. For example, using 10 units of soluble TGase/g resulted in extensive cross-linking of alpha-lactalbumin and beta-lactoglobulin in WPI, as evidenced by SDS-PAGE and Western blotting results. Interestingly, the gelling point of WPI solutions increased from 68 to 94 degrees C after a 4-h reaction, and the gel strength was drastically decreased (lower storage modulus, G'). Thus, extensive intra- and interchain cross-linking probably caused formation of polymers that were too large for effective network development. These results suggest that a process could be developed to produce heat-stable whey proteins for various food applications.     

Protein-stabilized nanoemulsions and emulsions: comparison of physicochemical stability, lipid oxidation, and lipase digestibility

The properties of whey protein isolate (WPI) stabilized oil-in-water (O/W) nanoemulsions (d(43) ≈ 66 nm; 0.5% oil, 0.9% WPI) and emulsions (d(43) ≈ 325 nm; 0.5% oil, 0.045% WPI) were compared. Emulsions were prepared by high-pressure homogenization, while nanoemulsions were prepared by high-pressure homogenization and solvent (ethyl acetate) evaporation. The effects of pH, ionic strength (0-500 mM NaCl), thermal treatment (30-90 °C), and freezing/thawing on the stability and properties of the nanoemulsions and emulsions were compared. In general, nanoemulsions had better stability to droplet aggregation and creaming than emulsions. The nanoemulsions were unstable to droplet flocculation near the isoelectric point of WPI but remained stable at higher or lower pH values. In addition, the nanoemulsions were stable to salt addition, thermal treatment, and freezing/thawing (pH 7). Lipid oxidation was faster in nanoemulsions than emulsions, which was attributed to the increased surface area. Lipase digestibility of lipids was slower in nanoemulsions than emulsions, which was attributed to changes in interfacial structure and protein content. These results have important consequences for the design and utilization of food-grade nanoemulsions.     

Oleosins of Arabidopsis thaliana: expression in Escherichia coli, purification, and functional properties

The interfacial behavior of oleosins, the most abundant proteins from seeds oil bodies, was investigated using the pendant drop method at water/oil interfaces and compared to the behavior of beta-casein and lysozyme, proteins with contrasted emulsifying properties. Recombined high (rS3) and low (rS4) molecular weight oleosins comprising N-terminal histidine tags were purified to electrophoretic homogeneity. rS3 decreased the interfacial tension at the oil/water interface better than rS4, oleosins being more efficient than beta-casein. Oleosins formed aggregates when spread on noncompressed phospholipid (PL) films at the air/water interface as observed using a Langmuir-Blodgett balance equipped with a Brewster angle microscope. Oleosin spread at the surface of a compressed PL monolayer (5-20 mN/m) did not aggregate. Pressure increased immediately and proportionally to the amount of protein spread on the monolayer. The results stress the capacity of oleosins to be inserted in oil and in PL monolayers, which is of particular relevancy to their potential uses as water/oil emulsifiers.     

适宜无机盐及浓度抑制麦胚脂肪酶存在时油水界面张力

为了探明无机盐稳定化脂肪酶的潜在机理,该文以小麦胚芽脂肪酶为研究对象,基于界面酶学的分析方法,研究添加浓度介于1.0×10-9~1.0×10-2 mol/L的Na~+、K+、Ca~(2+)、Mg~(2+)的氯化物对小麦胚芽脂肪酶存在的油-水界面特性的影响。结果表明,当小麦胚芽脂肪酶体系浓度为1.7×10-6 mol/L时,一价金属中Na~+更有利于抑制油-水界面的表面张力(P0.05),对麦胚脂肪酶存在时的油水界面特性影响也较大;二价金属离子Ca~(2+)对界面张力的影响趋势与一价离子不同,在高浓度时反而增加界面张力;当油水界面上存在脂肪酶的催化底物(三油酸甘油酯)和产物(油酸)时,添加浓度分别为10-6、10-6、10-4和10-9mol/L的Na~+、K~+、Ca~(2+)、Mg~(2+)均可一定程度上降低油水界面张力,从而降低麦胚脂肪酶的作用效果,三油酸甘油酯存在时Mg~(2+)的作用效果最明显(P0.05),油酸存在时Na+的作用效果最明显(P0.05)。综上,无机盐金属离子主要通过影响麦胚脂肪酶在油水界面的聚集行为及底物结构状态起到钝化麦胚脂肪酶的作用,该结果可为麦胚脂肪酶存在时界面的活性调控及麦胚的稳定化处理提供参考。     

Interfacial shear rheology of aged and heat-treated beta-lactoglobulin films: displacement by nonionic surfactant

Interfacial shear rheology of adsorbed beta-lactoglobulin films (bulk protein concentration 10(-)(3) wt %) has been studied over the temperature range 20-90 degrees C using a two-dimensional Couette-type viscometer. Effects of the type of interface (air-water, triolein-water, and n-dodecane-water), the pH (2.0, 5.6, 6.0, 7.0, and 9.0), and the extent of the heat treatment have been assessed via measurements of changes in the apparent interfacial shear viscosity and elasticity before and after the addition of increasing amounts of nonionic surfactant Tween 20 (polyoxyethylene sorbitan monolaurate). The highest interfacial viscosities were obtained at the n-dodecane-water interface and the lowest at the air-water interface. Competitive displacement of protein from the interface by Tween 20 was easier at the air-water and n-dodecane-water interfaces as compared to the triolein-water interface. The surface shear viscosity was higher and the displacement by Tween 20 more difficult as the isoelectric point of the protein was approached, which is in agreement with the presence of a more strongly cross-linked protein network at the interface. The effect of heat treatment was dependent on the pH of the aqueous solution. No simple relationship between the surface rheological characteristics and the ease of displacement by Tween 20 could be inferred.     

Influence of competitive adsorption on flocculation and rheology of high-pressure-treated milk protein-stabilized emulsions

The effect of high-pressure treatment (HPT) on the droplet-size distribution and small-deformation rheology of oil-in-water emulsions containing beta-lactoglobulin and a nonionic surfactant or sodium caseinate has been investigated at neutral pH. Addition of Tween 20 (polyoxyethylenesorbitan monolaurate) to a beta-lactoglobulin-stabilized emulsion results in competitive displacement of the adsorbed globular protein film and, following HPT, the formation of a less flocculated emulsion. The age of the beta-lactoglobulin-stabilized emulsion prior to addition of sodium caseinate influences the competitive adsorption behavior. The strengthening of the beta-lactoglobulin layer with time makes it more resistant to disruption by sodium caseinate. The level of pressure-induced flocculation of beta-lactoglobulin-coated oil droplets depends on the intensity of processing conditions and on the degree of interfacial displacement. In contrast, beta-lactoglobulin added after emulsification appears to show little evidence of competitive adsorption behavior at the caseinate oil-water interface. Changes in the rheological properties of these latter systems following HPT can be attributed to pressure-induced denaturation and gelation of beta-lactoglobulin in the continuous phase of the emulsion.     

高压微射流压力对大豆蛋白-大豆多糖体系功能性质的影响

为提升大豆分离蛋白（soy protein isolate,SPI）的功能性质,该文引入大豆可溶性多糖（soybean soluble polysaccharides,SSPS）,构建大豆分离蛋白-大豆可溶性多糖体系（SPI-SSPS）,研究动态高压微射流（dynamic high-pressure microfluidization,DHPM）处理对SPI-SSPS功能特性的影响。分别采用0,60,100,140和180 MPa的 DHPM压力处理SPI-SSPS,探究不同压力对SPI-SSPS起泡特性、乳化特性、溶解性、粒度分布和表面疏水性的影响。结果表明,DHPM处理能提高SPI的溶解性和起泡特性,且SSPS的存在能显著提高DHPM对SPI功能性质的改善效果（P<0.05）。100和60 MPa的DHPM处理能使SPI-SSPS呈现较高的起泡能力和起泡稳定性,分别为未处理样品的1.2和2.4倍。140 MPa的DHPM处理使SPI-SSPS溶解性较强,为未处理样品的1.8倍。然而,DHPM处理会显著降低SPI-SSPS的乳化特性、粒径和表面疏水性（P<0.05）。随着处理压力的增加,SPI-SSPS的粒度和表面疏水性逐渐降低,在180MPa的DHPM处理下SPI-SSPS具有较小的粒径和较低的荧光强度。综上所述,DHPM结合SSPS改性技术可用于改善SPI的功能性质（如溶解性、起泡性）,促进SPI在食品工业的应用。该文的研究结果可为SPI的功能性质改性提供参考。