Physical and thermo-mechanical properties of whey protein isolate films containing antimicrobials, and their effect against spoilage flora of fresh beef

The effectiveness of antimicrobial films against beef's spoilage flora during storage at 5 °C and the impact of the antimicrobial agents on the mechanical and physical properties of the films were examined. Antimicrobial films were prepared by incorporating different levels of sodium lactate (NaL) and -polylysine (-PL) into sorbitol-plasticized whey protein isolate (WPI) films. The moisture uptake behavior and the water vapor permeability (WVP) were affected only by the addition of NaL at all concentrations used since an increased water uptake and permeability were observed with the addition of NaL into the protein matrix. An increase of the glass transition temperature (5–15 °C) of the sorbitol region, as determined by Dynamic Mechanical Thermal Analysis (DMTA), was caused by the addition of -PL into the WPI specimens. Instead, incorporation of NaL into the protein matrix did not alter its thermo-mechanical behavior. The addition of NaL at concentrations of 1.0% and 1.5% w/w in the film-forming solution resulted in a decline of maximum tensile strength (σ_max) and Young modulus (E). A decrease of E and σ_max, accompanied with an increase in elongation at break (%EB), was also observed with increasing -PL concentration, at moisture contents higher that 10% (w/w). The antimicrobial activity of the composite WPI films was tested on fresh beef cut portions. The maximum specific growth rate (μ_max) of total flora (total viable count, TVC) was significantly reduced with the use of antimicrobial films made from 0.75% w/w -PL in film-forming solutions (p < 0.05), while the growth of Lactic Acid Bacteria was completely inhibited. Significant inhibition of growth of the total flora and pseudomonads was also observed with the use of films made with protein solutions containing 2.0% w/w NaL. These results pointed to the effectiveness of the antimicrobial whey protein films to extend the shelf life of fresh beef.     

Physico-chemical properties of whey protein isolate films containing oregano oil and their antimicrobial action against spoilage flora of fresh beef

Antimicrobial films were prepared by incorporating different levels of oregano oil (0.5%, 1.0%, and 1.5% w/w in the film forming solution) into sorbitol-plasticized whey protein isolate (WPI) films. The moisture uptake behavior and the water vapor permeability (WVP) were not affected by the addition of oregano oil at any of the concentrations used. A reduction of the glass transition temperature (∼10–20 °C), as determined by dynamic mechanical thermal analysis (DMTA), was caused by addition of oil into the protein matrix. A decrease of Young modulus (E) and maximum tensile strength (σ_max) accompanied with an increase in elongation at break (%EB) was observed with increasing oil concentration up to a level of 1.0% (w/w). Wrapping of beef cuts with the antimicrobial films resulted in smaller changes in total color difference (ΔΕ) and saturation difference (Δ_chroma) during refrigeration (5 °C, 12 days). The maximum specific growth rate (μ_max) of total flora (total viable count, TVC) and pseudomonads were significantly reduced (P < 0.05) by a factor of two with the use of antimicrobial films (1.5% w/w oil in the film forming solution), while the growth of lactic acid bacteria was completely inhibited. These results pointed to the effectiveness of oregano oil containing whey protein films to increase the shelf life of fresh beef.     

肉桂精油-玉米淀粉基抗菌膜的制备及其性能

为研究新型抗菌降解包装材料,筛选肉桂精油等4?种植物精油,以玉米淀粉、壳聚糖和魔芋葡甘露聚糖为成膜基质,甘油为增塑剂,吐温-80为表面活性剂,研究肉桂精油添加对复合膜机械性能、光学性能、阻水性能和抑菌性能的影响。结果表明：4?种精油对金黄色葡萄球菌、大肠杆菌和沙门菌的抗菌活性依次为肉桂精油＞牛至精油＞百里香精油＞迷迭香精油。随着肉桂精油质量浓度增加,复合膜的抗拉强度和水蒸气透过系数降低,断裂伸长率和不透明度升高。当肉桂精油质量浓度在15.0～20.0?g/L时,复合膜色泽指数a*值无明显差异（P＞0.05）,L*值显著降低,b*值和ΔE值显著增加（P＜0.05）。添加肉桂精油显著提高了玉米淀粉基膜的抗菌能力（P＜0.05）,精油与吐温-80相互作用对革兰氏阴性的大肠杆菌具有协同作用,而对革兰氏阳性的金黄色葡萄球菌具有拮抗作用。当肉桂精油质量浓度为20.0?g/L时,膜具有较好的物理性能和抗菌效果。本研究可为肉桂精油-玉米淀粉基可降解抗菌膜生产工艺参数的进一步优化提供参考。     

Hake proteins edible films incorporated with essential oils: Physical,mechanical, antioxidant and antibacterial properties

Physical, mechanical, antioxidant and antimicrobial properties of hake protein films incorporated with citronella, coriander, tarragon and thyme oils were investigated. Dried hake proteins were solubilized at pH 11.0 (protein concentration in film forming solution ca. 0.9%) and glycerol (59% w/w of protein) and 0.25 ml of each essential oil per gram of protein was added. Films obtained were homogeneous and transparent with a yellowish colour. The addition of the different essential oils reduced the water vapour permeability but increased the solubility of films in water. The amount of protein released from the films depended on the oil added. Among all essential oils incorporated-films the thyme oil films exhibited the lowest mechanical properties (puncture force and elongation at break). Conversely, films with thyme oil added presented the highest inhibition against Shewanella putrefaciens. Antioxidant activity of hake protein films generally increased with the incorporation of essential oils as indicated by DPPH radical scavenging activity and reducing power.     

Antibacterial Effects of Allspice, Garlic, and Oregano Essential Oils in Tomato Films Determined by Overlay and Vapor-Phase Methods

ABSTRACT:  Physical properties as well as antimicrobial activities against  Escherichia coli  O157:H7,  Salmonella enterica , and  Listeria monocytogenes  of allspice, garlic, and oregano essential oils (EOs) in tomato puree film-forming solutions (TPFFS) formulated into edible films at 0.5% to 3% (w/w) concentrations were investigated in this study. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor-phase diffusion of the antimicrobial from the film to the bacteria. The results indicate that the antimicrobial activities against the 3 pathogens were in the following order: oregano oil > allspice oil > garlic oil.  Listeria monocytogenes  was less resistant to EO vapors, while  E. coli  O157:H7 was more resistant to EOs as determined by both overlay and vapor-phase diffusion tests. The presence of plant EO antimicrobials reduced the viscosity of TPFFS at the higher shear rates, but did not affect water vapor permeability of films. EOs increased elongation and darkened the color of films. The results of the present study show that the 3 plant-derived EOs can be used to prepare tomato-based antimicrobial edible films with good physical properties for food applications by both direct contact and indirectly by vapors emanating from the films.     

Optimization of medium constituents for ε-poly-L-lysine fermentation with response surface methodology

Abstract: ɛ-Poly-L-lysine (ɛ-PL) is a novel food biopreservative with broad antimicrobial activity. In the present study, single-factor experiments were applied to screen optimal carbon and nitrogen sources that affect the yield of a ɛ-PL-producing strain, Streptomyces violaceusniger, which was obtained in our laboratory recently. Box-Behnken design and response surface methodology (RSM) were adopted to derive a statistical model for optimizing the composition of the fermentation medium. The results showed that the main factors that affect ɛ-PL production were glucose, carbon source; peptone, organic nitrogen source; and (NH₄)₂SO₄, inorganic nitrogen source. The optimum fermentation medium for ɛ-PL production of S. violaceusniger consisted of (g/L) glucose, 62.49; peptone, 5.71; (NH₄)₂SO₄, 11.19; MgSO₄, 0.5; FeSO₄, 0.03; ZnSO₄, 0.04; KH₂PO₄, 1.36; and Na₂HPO₄.12H₂O, 3.58. When cultured in the optimum medium, the ɛ-PL production was an average of 0.349 ± 0.025 mg/mL, which was 1.75 times higher than the initial medium. Practical Application: The present study illustrated the potential use of response surface methodology with the Box-Behnken design in biotechnology. Results from this work suggested that ɛ-PL production was increased greatly with the optimal medium constituents by the potential organism, S. violaceusniger, which may be a good resource for the industrial production of ɛ-PL in future.     

Antibacterial activity and mechanical properties of partially hydrolyzed sago starch-alginate edible film containing lemongrass oil

ABSTRACT:  Edible films were prepared from a mixture of partially hydrolyzed sago starch and alginate (SA). Lemongrass oil (0.1% to 0.4%, v/w) and glycerol (0% and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antimicrobial activity, water vapor permeability (WVP), tensile strength (TS), percent elongation at break (%E), and water solubility (WS). Fourier transform infrared (FTIR) spectroscopy was conducted to determine functional group interactions between the matrix and lemongrass oil. The zone of inhibition was increased significantly ( P < 0.05) by addition of lemongrass oil at all levels in the presence and the absence of glycerol. This indicates that the film containing lemongrass oil was effective against Escherichia coli O157:H7 at all levels. In the absence of glycerol, the tensile strength of film decreased as the oil content increased, but there was no significant ( P > 0.05) difference in percent elongation. The percent elongation at break and WVP values for film with 20% glycerol was found to be increased significantly ( P < 0.05) with an increase in lemongrass oil content. Addition of lemongrass oil did not have any interaction with the functional groups of films as measured by FTIR.     

Thermal Inactivation and Postthermal Treatment Growth during Storage of Multiple Salmonella Serotypes in Ground Beef as Affected by Sodium Lactate and Oregano Oil

ABSTRACT:  We assessed the heat resistance of  Salmonella  in raw ground beef in both the absence and presence of sodium lactate, oregano oil, and in combinations of these 2 GRAS-listed ingredients, and determined their bactericidal or bacteriostatic activities during postthermal treatment storage at 15 °C. A cocktail of 8 serotypes of  Salmonella  spp. was inoculated into ground beef supplemented with sodium lactate (NaL) (1.5% and 3%) and/or oregano oil (0.5% and 1%) to obtain approximately 8 log CFU/g. The ground beef samples (3 g) were vacuum-packed and heated at 60, 65, or 71 °C in a circulating water bath for selected times to inactivate approximately 5 to 6 log CFU/g of the pathogen, and then stored at 15 °C for 15 and 30 d. Results show that especially at the lower cooking temperatures, addition of oregano oil increased the inactivation rate of  Salmonella  spp., whereas addition of NaL alone exhibited a protective effect against lethality and decreased the rate. Addition of combinations of oregano oil and NaL overcame this protective effect. During subsequent posttreatment storage for 15 d,  Salmonella  populations in the controls and in samples containing 0.5% oregano (60 and 65 °C) or 1% oregano oil (60 °C) increased to 4.5 to 6 log CFU/g. The values for all other samples were at or near undetectable levels. Results from the 30-d storage study were similar. These findings indicate that lactate and oregano oil may be used to render  Salmonella  spp. more susceptible to the lethal effect of heat and to inhibit growth of  Salmonella  spp. that survive heat treatments.     

The effect of oregano essential oil on survival/death of Salmonella typhimurium in meat stored at 5°C under aerobic,VP/MAP conditions

The effect of oregano essential oil and film permeability on the behaviour of Salmonella typhimurium in sterile and naturally contaminated beef fillets stored under aerobic, modified atmosphere consisting of 40% CO₂ /30% O₂ /30% N₂ (MAP) and a vacuum packaged (VP) environment was studied during storage at 5°C. In samples without oregano essential oil, the pathogen survived under all storage conditions. Addition of oregano essential oil at a concentration of 0·8% v/w resulted in an initial reduction of 1–2 log₁₀ cfu g⁻¹ of the majority of the microbial population of meat with lactic acid bacteria and S. typhimurium showing the greatest reductions in all gaseous environments regardless of film permeability. The use of VP/MAP at chill temperatures in conjunction with oregano essential oil as a means of controlling spoilage and safety of meat is discussed.     

Chitosan-whey protein isolate composite films for encapsulation and stabilization of fish oil containing ultra pure omega-3 fatty acids

Chitosan (1.5%, w/v)-whey protein isolate (WPI, 5% w/v) composite films were developed for encapsulating and stabilizing fish oil (FO) containing 93.7% eicosapentaenoic acid (EPA). Chitosan-WPI film-forming solutions (FFS) were incorporated with 1.5% or 2% FO (w/v), 2% (w/v) glycerol, Tween 80 (3 times weight of FO), and 0.5% (w/v) oregano or rosemary essential oil (EO), and cast for films at room conditions. Dried films were stored at 2 °C for 30 d for evaluating encapsulation efficiency (EE), lipid stability, and film functionality. Total oil contents in films from FFS incorporating 1.5% or 2% FO were 28.1% to 32.5% and 33.4% to 37.3%, respectively, and free oil contents were 13.5% to 14.7% and 15.5% to 16.3%, respectively. EE, moisture content, and water activity of the films were 47.8% to 66%, 18.7% to 24.9%, and 0.42% to 0.50%, respectively, without significant difference among differently formulated films. Increasing FO concentration from 1.5% to 2% in FFS decreased tensile strength of the films from 0.57-0.73 to 0.34-0.44 MPa, but not the film elongation. Addition of oregano EO in FFS retarded lipid oxidation of the fish oil encapsulated in the films, in which a 43% to 53% reduction in thiobarbituric acid-reactive substances value and 39% to 51% reduction in peroxide value were achieved. Chitosan-WPI composite films with incorporation of oregano essential oil could be applied as a simple and economic means for encapsulating and stabilizing fish oil for fortifying omega-3 fatty acids in various applications.     

可食性大豆分离蛋白膜制备与性质

为探索新型生物膜材料的制备,以大豆分离蛋白为基本材料,探究大豆分离蛋白(SPI)、增塑剂(甘油)、还原剂(Na_2SO_3)、乙醇等添加量和处理温度、成膜液pH、成膜介质等条件对膜的完整率、厚度、透光率、水溶率、水蒸气透过系数、透油性等性质的影响。当SPI浓度在2%~6%时,随着添加量的增加,成膜变得容易,但是膜的厚度增加、水蒸气透过系数和透油系数变大、色泽变深。甘油添加量在2%以下可以改善膜的柔韧性,同时降低膜的透气性能和透油性。添加5%的乙醇也可以降低膜的透气性和透油性。添加0.1%的Na_2SO_3可以改善膜的色泽,同时降低膜的透油性。适当提高处理温度和溶液pH可以降低膜的透气性和透油性。     

Functional Properties of Antimicrobial Lysozyme-Chitosan Composite Films

ABSTRACT: Lysozyme-chitosan composite films were developed for enhancing the antimicrobial properties of chitosan films. A 10% lysozyme solution was incorporated into 2% chitosan film-forming solution (FFS) at a ratio of 0%, 20%, 60%, and 100% (w lysozyme/w chitosan). Films were prepared by solvent evaporation. Lysozyme release from the film matrix, the antimicrobial activity of films against Escherichia coli and Streptococcus faecalis , and basic film properties were investigated. The lysozyme release proportionally increased with increasing initial concentration of lysozyme in the film matrix, and the amount of released lysozyme was in natural log relationship with time. The films with 60% lysozyme incorporation enhanced the inhibition efficacy of chitosan films against both S. faecalis and E. coli , where 3.8 log cycles reduction in S. faecalis and 2.7 log cycles reduction in E. coli were achieved. Water vapor permeability of the chitosan films was not affected by lysozyme incorporation, whereas the tensile strength and percent elongation values decreased with increased lysozyme concentration. Scanning electron microscopy images revealed that lysozyme was homogeneously distributed throughout the film matrix. This study demonstrated that enhanced antimicrobial activity of lysozyme-chitosan composite films can be achieved by incorporating lysozyme into chitosan, thus broadening their applications in ensuring food quality and safety.     

Release of active compounds from agar and agar–gelatin films with green tea extract

Active biodegradable films based on agar and agar–fish gelatin were developed by the incorporation of green tea aqueous extract to the film forming solution. The effect of the partial replacement of agar by fish skin gelatin as well as the addition of the green tea extract on the physical properties of the resultant films was evaluated. Special attention was given to the release of antioxidant and antimicrobial compounds from the agar film matrices with and without gelatin. Agar–gelatin films were less resistant and more deformable than agar films. The inclusion of green tea extract decreased tensile strength and elongation at break in both agar and agar–gelatin films. Water vapour permeability and water resistance was not affected either by the replacement of agar by gelatin or the addition of green tea extract, but the water solubility noticeably increased in the films containing green tea extract. The presence of gelatin in the agar–green tea matrix film hindered the release of total phenolic compounds, catechins and flavonols in water. As a consequence, the antioxidant power released by the films was lower in the case of films containing gelatin. However, the antimicrobial activity of the films was not affected by the presence of gelatin.     

牛至精油羧甲基纤维素活性包装膜制备及其抗氧化和抗菌性能研究

本文利用牛至精油与羧甲基纤维素混合,制备具有抗氧化和抗菌性能的可降解活性包装膜。通过测定其厚度、颜色、机械性能和微观结构等,探究含有0%、1%、2%、3%牛至精油膜的结构和性能。结果表明:精油的加入一定程度增加了膜样的厚度,使膜样表面呈现较浅的棕黄色。精油与羧甲基纤维素相结合,膜样断裂伸长率随精油添加量增加无显著变化,抗拉强度显著降低(p>0.05)。微观结果显示,膜样表面出现微孔,使精油能够从中释放从而发挥抗氧化和抑菌作用。红外光谱的结果显示,牛至精油的加入没有与羧甲基纤维素发生化学反应。通过测定DPPH自由基清除率发现,牛至精油的加入能够显著提高膜的抗氧化能力,并随着精油浓度的提高而增强,但浓度为2%与3%差异并不显著(p>0.05)。利用琼脂扩散法发现,精油能够显著抑制金黄色葡萄球菌和大肠杆菌的生长,抑菌效果随着精油加入量的提升而显著提升(p<0.05)。综合膜样的性能和经济角度考虑得出,2%牛至精油含量的羧甲基纤维素膜具有良好的物理性能和较强的抗氧化和抑菌性能。     

Antimicrobial Activity of Chitosan Films Enriched with Essential Oils

ABSTRACT: Antimicrobial and physicochemical properties of chitosan films and chitosan films enriched with essential oils (EO) were determined in vitro and on processed meat. Antimicrobial effects of pure EO of anise, basil, coriander, and oregano, and of chitosan-essential oil films against Listeria monocytogenes and Escheri-chia coli O157:H7 were determined by an agar diffusion test. The antibacterial effects of the EO were similar when applied alone or incorporated in the films. The intensity of antimicrobial efficacy was in the following order: oregano > > coriander > basil > anise. The chitosan films and chitosan-oregano EO films were applied on inoculated bologna samples and stored 5 d at 10 °C. Pure chitosan films reduced L. monocytogenes by 2 logs, whereas the films with 1% and 2% oregano EO decreased the numbers of L. monocytogenes by 3.6 to 4 logs and E. coli by 3 logs. Pure chitosan films were 89 μm thick, whereas addition of 1% and 2% oregano EO increased thickness to 220 and 318 μm, respectively. During application on bologna discs, the films absorbed moisture, resulting in the final thickness of 143, 242, and 333 μm, respectively. Addition of oregano essential oil into the chitosan films decreased water vapor permeability, puncture and tensile strength, but increased elasticity of the films. The films have the potential to be used as active biodegradable films with strong antimicrobial effects.     

Physical and mechanical properties of chitosan films as affected by drying methods and addition of antimicrobial agent

Incorporation of an antimicrobial agent into a biopolymer matrix not only affects the antimicrobial property, but also the physical, mechanical and barrier properties of the resulted films. In addition to the effect of antimicrobial agent different drying methods that are used to prepare the films should also be considered. The aim of this study was to investigate the combined effects of drying methods, namely, hot air drying and low-pressure superheated steam drying (LPSSD), and addition of a natural antimicrobial agent, namely, galangal extract, at concentrations of 0%, 0.6%, 0.9%, 1.2% and 1.5% (w/w film forming solution) on selected physical properties (thickness, moisture content, color and opacity), mechanical properties (tensile strength and percent elongation), barrier properties (water vapor and oxygen permeabilities), degree of crystallinity and degree of swelling of antimicrobial films prepared from chitosan. X-ray diffraction (XRD) analysis, Fourier-transform infrared (FTIR) spectroscopy as well as dynamic mechanical analysis (DMA) were also performed and their results used to explain the observed combined effects. The combined effects were noted to have a statistically insignificant influence on the moisture content, thickness and water vapor permeability of the films. On the other hand, the combined effects had a statistically significant influence on the color, degree of crystallinity, degree of swelling, tensile strength, percent elongation and oxygen permeability of the films. Only the galangal extract concentration had a statistically significant influence on the film opacity. The DMA patterns and FTIR spectra confirmed the formation of crosslinkage interactions between the galangal extract and chitosan matrix.     

Liquid and vapour water transfer through whey protein/lipid emulsion films

BACKGROUND: Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films. RESULTS: Films were cast from heated (80 °C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg^?1 of water) containing glycerol (50 g kg^?1 of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light‐scattering granulometry, differential scanning calorimetry, wetting properties and water vapour permeability (WVP) were made. The emulsion structure in the film suspension changed significantly during drying, with oil creaming and coalescence occurring. Increasing oil concentration led to a 2.5‐fold increase in surface hydrophobicity and decreases in WVP and denaturation temperature (T_max). CONCLUSION: Film structure and surface properties explain the moisture absorption and film swelling as a function of moisture level and time and consequently the WVP behaviour. Small amounts of rapeseed oil favourably affect the WVP of WPI films, particularly at higher humidities. Copyright © 2010 Society of Chemical Industry     

Antibacterial activity against E. coli O157:H7, physical properties, and storage stability of novel carvacrol-containing edible tomato films

Edible films containing plant antimicrobials are gaining importance as potential treatment to extend product shelf life and reduce risk of pathogen growth on contaminated food surfaces. The main objective of the present study was to evaluate the antimicrobial activities, storage stabilities, and physical-chemical-mechanica1 properties of novel edible films made from tomatoes containing carvacrol, the main constituent of oregano oil. The antimicrobial activities against E. coli O157:H7 and the stability of carvacrol were evaluated during the preparation and storage of tomato-based films made by 2 different casting methods, continuous casting and batch casting. Antimicrobial assays of tomato films indicated that optimum antimicrobial effects occurred with carvacrol levels of approximately 0.75% added to tomato purees before film preparation. HPLC analysis of the films indicated that the carvacrol concentrations and bactericidal effect of the films remained unchanged over the storage period of up to 98 d at 5 and 25 degrees C. Carvacrol addition to the tomato puree used to prepare the films increased water vapor permeability of tomato films. The continuous method for casting of the films appears more suitable for large-scale use than the batch method. This 1st report on tomato-based edible antimicrobial tomato films suggests that these films have the potential to prevent adverse effects of contaminated food and promote human health associated with the consumption of tomatoes.     

Combined effects of lemon essential oil and surfactants on physical and structural properties of chitosan films

The aim of this research was to evaluate the effects of lemon essential oil (LO, at 0.5%, 1%, 2% v/v film‐forming solutions) and surfactants (Tween 80 and Span 80 at 0.1% v/v film‐forming solutions) on physical, optical and structural properties of chitosan (CH) films. The films were formed by casting method. Results showed that the incorporation of LO provoked a decrease in water content, water vapour permeability (WVP) and mechanical properties. Less transparency and higher total colour difference were observed in CH–LO composite films. The addition of surfactants significantly increased WVP and solubility in water of CH–LO films. The film containing Tween 80 showed lower mechanical strength and higher transparency. The morphology was different depending on the LO contents and surfactant types used. Tween 80 improved the stability of LO in the film, whereas Span 80 promoted the movement of oil droplets to the film surface.     

ε-聚赖氨酸与卵白蛋白间相互作用及对抑菌活性的影响

为表征带正电ε-聚赖氨酸与带负电卵白蛋白间的相互作用以及相互作用对ε-聚赖氨酸抑菌活性的影响,本 实验通过测定ε-聚赖氨酸与卵白蛋白复合溶液的ζ-电位和浊度,对ε-聚赖氨酸与卵白蛋白之间的相互作用进行了表 征。通过抑菌实验研究ε-聚赖氨酸与卵白蛋白之间的相互作用对ε-聚赖氨酸抑菌活性的影响。结果表明卵白蛋白可 与ε-聚赖氨酸形成带不同电荷的复合物,进而导致ε-聚赖氨酸对大肠杆菌的抑菌效果下降,这可能是由于ε-聚赖氨 酸与卵白蛋白分子之间发生静电结合,减少了其与带负电微生物表面间的相互作用。本研究初步建立了ε-聚赖氨酸 与卵白蛋白及大肠杆菌之间的相互作用模型,有利于进一步揭示在复杂食品体系中ε-聚赖氨酸与蛋白质的相互作用 及其对ε-聚赖氨酸抑菌活性的影响。