Combined effect of aminoacids and microbial transglutaminase on gelation of low salt surimi content under high pressure processing

The paper examines the effect of High Pressure Processing (HPP) (300 MPa), the incorporation of microbial transglutaminase (MTGase) and the addition of different additives such as lysine and cystine, as potential enhancers of low-salt (0.3%) surimi gel. Effects on myosin as the molecule responsible for gelation was monitored by Fourier transform infrared spectroscopy, Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), and dynamic rheometry measurements. The effects on physicochemical properties of surimi gels were determined by Folding and Puncture tests and water holding capacity.Results indicated an increase in β-sheet when HPP was applied or additives added (cystine and lysine), especially when samples are treated with MTGase. Protein aggregation due to HPP and the additives resulted in lower myosin heavy chain (MHC) band density in the SDS–PAGE. Rheometry measurements indicated that MTGase activity was prompted by the incorporation of cystine and lysine in the absence of HPP. Also, HPP assisted gelation, resulting in improved mechanical properties of the gels. Samples containing additives, with or without HPP, exhibited the highest Folding test scores, indicating greater network flexibility. Lastly, water binding capacity was also enhanced by both additives and HPP.Industrial relevanceThe industrial relevance of the present work is focused on the appropriated gelation of myofibrillar proteins which is an essential step in the elaboration of surimi-based products. Sodium chloride has an important role in that fact inducing protein unfolding and solubilization. The reduction in NaCl content, following the NAOS strategy, required the application of different technologies to facilitate surimi adequate gelation. High-pressure processing has been commonly used as an innovative technology to prolong shelf life but it can be successfully used to induce proteins gelation. Due to that ability, the use of high pressure on surimi-based products result an interesting tool to facilitate surimi gelation. The use of Microbial transglutaminase (MTGase) alone or in combination with some aminoacids such as lysine and cystine can significantly improve surimi gelation added in a very small proportion.     

Effects of high pressure,microwave and ultrasound processing on proteins and enzyme activity in dairy systems — A review

High-pressure processing (HPP), microwaves (MW) and ultrasound (US) are used for pasteurization with minimum heat input. They also alter physico-chemical properties of milk proteins and enzymes. This article aims at identifying the important changes in milk proteins imparted by these three processing technologies. HPP dissociates casein micelles at low pH (<6.7) and concentrations (<4% w/w), while β-LG is the most pressure sensitive whey protein due to the presence of free thiol groups. Milk enzyme activity is inhibited at higher pressures (>400 MPa). MW treatment denatures whey proteins rapidly, even below their thermal denaturation temperatures. High-power MW treatment (e.g. 60 kW) deactivates enzymes by denaturing them. However, low-power controlled MW irradiation (e.g. 30 W) improves enzyme activity. Ultrasound can homogenize protein aggregates in dairy systems and cause whey protein denaturation. Sonication under applied pressure and heat (e.g. 3.5 kg/cm², 126.5 °C) causes enzyme inhibition while mild sonication conditions can improve enzyme activity.Industrial relevanceHPP, MW and US are gaining popularity in the dairy industry due to their ability to pasteurize and functionalize dairy streams with minimal heat input. This review offers insights into how these technologies can be used in isolation or in combination to alter milk proteins and enzyme activity for different academic and industrial applications. However, to fully understand the potential of HPP, MW and US treatment on dairy systems, further research is required in several areas including health related nutritional changes in milk and milk products caused by these technologies.     

Recent advances in protein derived bionanocomposites for food packaging applications

Abstract

This review article critically presents a comprehensive overview of the current advances in the research and development of proteins derived bionanocomposites used in food packaging applications. The recent interest in protein-based biomaterials is due to sustainability, renewability, biodegradability and low carbon footprint. The inherent drawbacks of proteins-based materials for food packaging applications are their low mechanical strength, poor thermal, barrier and inferior physicochemical properties. The nanoreinforced bio-based polymers called bionanocomposites provide an opportunity to overcome these issues and have ability to supersede non-biodegradable food packaging plastics produced from petroleum resources. So far, most studied protein derived bionanocomposites suitable for food packaging are soy protein isolates (SPI) and gelatin proteins. Layered silicates are the most promising nanofillers used to increase strength, improve heat resistance and enhance barrier properties of proteins derived materials while montmorillonites (MMT) is the most commonly used silicate nanofiller. This review emphases on the processing strategies used for proteins-based biomaterials, their mechanical and moisture barrier properties for food packaging applications. Different proteins and nanofillers that have been studied to date in proteins derived food packaging applications are also discussed in detail.     

Characteristics of Sodium Caseinate- and Soy Protein Isolate-Stabilized Emulsion-Gels Formed by Microbial Transglutaminase

ABSTRACT:  Protein-stabilized emulsion gels were prepared via microbial transglutaminase (mTGase) catalysis, and their physicochemical characteristics were examined. Emulsion oil droplet size and interfacial protein load were measured. The sodium caseinate and soy protein isolate emulsion gels exhibited different microstructures and physical properties. The emulsion gels improved the storage stability of aroma compounds. Rheological measurements of the emulsion gels revealed interesting strength, gelation kinetics, and thermal sensitivity properties. The mTGase-induced emulsion gels comprised a fine network which led to less release of aroma compounds upon storage than did emulsions. These results suggest that emulsion gels may be used to improve the texture of food emulsions and to control release of food aromas.     

蛋白质-卵磷脂复合体系功能特性的研究进展

蛋白质与卵磷脂间发生的相互作用可以增强蛋白质功能特性,且二者形成的复合体系不仅能够作为递送系统传递生物活性物质、药物等以达到在胃肠道中的缓释效果,提高包埋物质的装载率及体外释放度,还能够实际应用于食品工业中提高我国传统蛋白基产品的质量及拓宽种类,如蛋白粉、婴儿配方乳以及运动营养食品等。本文综述了玉米醇溶蛋白、大豆蛋白、卵磷脂的理化性质和功能特性,蛋白-卵磷脂二者间的相互作用对蛋白的改善,蛋白-卵磷脂复合纳米颗粒、乳液及凝胶的特性,以及复合体系在食品工业、医药等领域作为递送系统和提高食品质量的应用,为改善单一蛋白体系的稳定性及提高其应用价值提供参考价值依据,对促进我国蛋白基食品产业高质量发展具有重要意义。     

Effect of high pressure processing on heat-induced gelling capacity of blue crab (Callinectes sapidus) meat

There has been increasing use of High pressure processing (HPP) in the fishery industry since this technology facilitates shellfish shucking. Nevertheless, there is limited information about the effect of HPP on protein functional properties of some shellfish. The aim of this study was to evaluate the effect of 100, 300 and 600 MPa/5 min on the gelling capacity of heat-induced (40 °C/30 min + 90 °C/20 min) blue crab (Callinectes sapidus) meat. HPP treatment resulted in crab meat gels with a lighter and reddish colour as compared to the control. HPP at 600 MPa induced the formation of high molecular aggregates from the denaturation-aggregation of myosin heavy chain. Pressurization at 100 MPa promoted the shift of α-helix structures to β-sheet and β-turn as compared with the other pressure levels. TPA values were higher in gels made at 100 MPa than at 300 or 600 MPa. Low pressure levels, then, increased the heat-induced gelling capacity of crab meat, improving the texture through modification of its protein structure.Industrial relevanceHigh pressure processing (HPP) technology has been successfully applied to several seafood products, both for processing and storage. However, in the case of blue crab meat it is important to study the effect of HPP on protein functional properties such as gelling capacity in order to optimize processing parameters for the preparation of high-quality restructured products. This paper reports the development of a HPP process (100, 300 and 600 MPa/5 min 40 °C/30 min + 90 °C/20 min) prior to thermal gelling for the preparation of crab meat gels. The application of 600 MPa produced considerable protein aggregation of gels, whereas with pressures below 300 MPa protein functionality can be modified to produce crab meat gels with adequate brightness, TPA values and a fresh, high-quality appearance. These results could provide a basis for further pressurization applications in the crab industry to create new seafood product analogues based on this kind of crab meat.     

Structure and shelf stability of milk protein gels created by pressure-assisted enzymatic gelation

In this work, pressure-assisted enzymatic gelation was applied to milk proteins, with the goal of enhancing the structure and stability of pressure-created milk protein gels. High-pressure processing (HPP) at 600 MPa, 3 min, and 5°C was applied to milk protein concentrate (MPC) samples of 12.5% protein concentration, both in the absence and in the presence of calf chymosin [up to 60 IMCU (international milk-clotting units)/kg of milk] or camel chymosin (up to 45 IMCU/kg of milk). Gel hardness, water-holding capacity, and degree of proteolysis were used to assess network strength and shelf stability. The processing trials and all measurements were conducted in triplicate. Statistical analyses of the data were performed by ANOVA, at a 95% confidence level. After HPP treatment, we observed significant structural changes for all samples. Pressurization of MPC, with or without chymosin addition, led to extensive protein aggregation and network formation. The strength of HPP-created milk protein gels without chymosin addition, as measured by the elastic modulus (G′), had a value of 2,242 Pa. The value of G′ increased with increasing chymosin concentration, reaching as high as 4,800 Pa for samples with 45 IMCU/kg of camel chymosin. During 4 wk of refrigerated storage, the HPP and chymosin MPC gels maintained higher gel hardness and better structural stability compared with HPP only (no chymosin) MPC gels. The water-holding capacity of the gels without chymosin remained at 100% during 28 d of refrigerated storage. The HPP and chymosin MPC gels had a lower water-holding capacity (91–94%) than the HPP-only counterparts, but their water-holding capacity did not decrease during storage. Overall, these findings demonstrate that controlled, fast structural modification of high-concentration protein systems can be obtained by HPP-assisted enzymatic treatment, and the created gels have a strong, stable network. This study provides insights into the possibility of using HPP for the development of milk-protein-based products with novel structures and textures and long refrigerated shelf life, along with the built-in safety imparted by the HPP treatment.     

Effects of Ultraviolet Light and High‐Pressure Processing on Quality and Health‐Related Constituents of Fresh Juice Products

Fresh juices are highly popular beverages in the global food market. They are perceived as wholesome, nutritious, all‐day beverages. For a fast growing category of premium juice products such as cold‐pressed juices, minimal‐processing nonthermal techniques such as ultraviolet (UV) light and high‐pressure processing (HPP) are expected to be used to extend shelf‐life while retaining physicochemical, nutritional, and sensory characteristics with reduced microbial loads. Also, UV light and HPP are approved by regulatory agencies and recognized as one of the simplest and very environmentally friendly ways to destroy pathogenic organisms. One of the limitations to their more extensive commercial application lies in the lack of comparative effects on nutritional and quality‐related compounds in juice products. This review provides a comparative analysis using 92 studies (UV light: 42, HPP: 50) mostly published between 2004 and 2015 to evaluate the effects of reported UV light and HPP processing conditions on the residual content or activity of bioactive compounds such as vitamins, polyphenols, antioxidants, and oxidative enzymes in 45 different fresh fruit and vegetable juices (low‐acid, acid, and high‐acid categories). Also, the effects of UV light and HPP on color and sensory characteristics of juices are summarized and discussed.     

Relationships Between Physicochemical Properties of Nonfish Protein and Textural Properties of Protein-incorporated Surimi Gel

The physicochemical properties of nonfish proteins were correlated with textural properties of nonfish protein gels and nonfish protein-incorporated surimi gels. Both cold and thermal hydration ability (by centrifugation) of nonfish proteins strongly correlated with compressive force (cohesiveness) of nonfish protein-incorporated surimi gel (r = 0.94 for cold; r = 0.95 for thermal). Hydrophobic amino acid groups in nonfish protein inversely correlated with compressive force (r =?0.88) and penetration force (r =?0.78) of nonfish protein-incorporated surimi gel. Thermal behavior of nonfish protein affected the gel characteristics of nonfish protein and surimi with nonfish protein-incorporated.     

Combination of high pressure and heat on the gelation of chicken myofibrillar proteins

The effects of combinations of high pressure and heat on chicken myofibrillar gels were investigated. High pressure was either applied simultaneously with heating (heating under pressure, HUP), before heating (PBH) or no high pressure with heat-only (HT). PBH treatment induced many similar properties in gels as did by HT treatment, except that PBH treatment promoted secondary structure transformation and formed more covalent bonds. HUP treatment resulted in less heat denaturation of the protein, induced fewer hydrophobic interactions and covalent bonds, hindered secondary and tertiary structural transformation, and formed a gel with a more porous microstructure. The gels induced by HUP treatment had softer texture and higher water holding capacity than gels induced by PBH or HT treatments. These findings suggest that high pressure with HUP treatment changes gel properties by resisting the heat-induced denaturation and gelation of myofibrillar proteins, while high pressure with PBH treatment alters gel properties by promoting denaturation of myofibrillar proteins.Industrial relevanceThe main constituents in meat are myofibrillar proteins, which are responsible for the functional properties of processed meat products. The gelation of myofibrillar proteins differs according to the sequence in which pressure/temperature combinations are applied. The pressure-modified protein interactions should be considered when adopting high pressure in meat product processing since the microstructure of the meat gel is affected by pressure, which would further affect water holding capacity and textural properties. HUP treatment showed its advantages in forming a fine microstructure and improving water-holding capacity.     

Effects of high pressure level and holding time on properties of duck muscle gels containing 1% curdlan

The effect of high pressure processing (HPP) on properties of duck muscle gels (DMG) containing 1% curdlan was investigated. The application of > 300 MPa could result in the decrease of cooking loss of DMG in water binding capacity, the increase of L value and the decrease of a value and b value in color, the increase of hardness, springiness, cohesiveness and chewiness in textural parameters (P < 0.05), while the pressure-holding time had no obvious influence. Those experimental results could be attributed to the interactions among protein molecules and the interactions between protein molecules and curdlan molecules created or enhanced by HPP. Overall, the use of curdlan instead of fat and the application of HPP may provide a novel approach to achieve low-fat (< 6% fat) and low-salt (1% salt) DMG products with good properties and high yields.

Industrial relevance

To provide healthier meat foods like low-fat (< 6% fat) and low-salt (about 1% salt) duck meat products, the application of HPP might be of great interest for industrial manufacture and can yield the products bearing high water binding capacity and good textural properties.     

Structure modification of stirred fermented milk gel due to laccase-catalysed protein crosslinking in a post-processing step

Laccases are a promising candidate for crosslinking milk proteins in stirred fermented milks. It was applied in a post-processing step due to its acidic pH optimum reported in literature for rebodying of the gel and an improvement in structure. A laccase preparation from Trametes versicolor had a lower oxidation activity in ultrafiltration permeate than in model buffer systems, and a pH optimum of 4.5. It was applied to stirred skim milk gels but no significant change in the storage modulus or apparent viscosity of yoghurt occurred. Confocal laser scanning micrographs showed a more porous structure of the milk gel. Some fresh cheese samples had improved rheological properties. A competing crosslinking activity and peptidolytic activity was assumed and smaller peptides were detected in acidified milk by fluorescence. Mass spectrometry of the laccase preparation returned mainly laccase sequences. Although this does not exclude proteases, it indicates that the radical mechanism of laccases may lead to protein degradation.Industrial RelevanceEnzymatic modification of milk proteins can alter the structure of fermented milk gels and even create new structures.Rheological properties can be improved via crosslinking, thus reducing costs due to the addition of protein powders or stabilisers.An innovative approach to combining biotechnology and food science and engineering is investigated.The study is interesting for both enzyme manufacturers and dairy companies as it aims to at least partially fill the knowledge gap between enzymology and their real-world application in dairy products.However, enzymatic treatment is an additional step and also incurs costs which should be taken into account.     

Crosslinking in polysaccharide and protein films and coatings for food contact – A review

BackgroundCrosslinking is the process of forming tridimensional networks by linking polymer chains by covalent or noncovalent bonds. It is useful for polysaccharide- and protein-based films and coatings to be applied to food surfaces, enhancing their water resistance as well as mechanical and barrier properties. Crosslinkers intended to be used for food contact materials must present low toxicity.Scope and approachThis review is a summary of the main crosslinking agents which have been used for protein and polysaccharide films and coatings, and which may be applied as food contact materials. The study emphasizes the mechanisms of crosslinking agents, the chemical groups involved, conditions for application, advantages and drawbacks, as well as examples of applications for food contact materials.Key findings and conclusionsCrosslinking is a promising technique to improve the performance and applicability of protein- and polysaccharide-based food contact materials, especially concerning their water sensitivity, which hinders many of their potential applications as food contact materials. Some aldehydes are very effective as crosslinkers, but they have been avoided in food contact materials because of possible migration of aldehyde residues to food, and less toxic compounds have been studied for those applications, such as phenolic acids, oxidized polysaccharides, and enzymes. Crosslinking techniques may help make protein- and polysaccharide-based materials more suitable for large-scale processing and applications in the future.     

Effect of non-meat proteins on hydration and textural properties of pork meat gels enhanced with microbial transglutaminase

The combined effect of incorporation of four non-muscle proteins, NMP (blood plasma, BP; sodium caseinate, SC; soy protein isolate, SPI; gelatin, G) at 2 g/100 g levels on hydration and textural characteristics of pork gels processed without or with 0.6 g/100 g microbial transglutaminase preparation (MTG) was investigated. Addition of SC and BP most favourably affected hydration properties and thermal stability, yielding lower cooking loss and expressible moisture for pork gels. Interactions between NMP and MTG were observed. Improvement of gel strength by addition of transglutaminase was observed for treatments containing SC and BP but not G nor soy isolate. Of the four proteins tested SC was found to be a superior substrate for MTG in enhancing textural properties of a gelled meat system. None of the tested ingredients was able to yield gel cohesiveness equivalent to the control containing 8% muscle proteins. Results of this study indicate a potential for using MTG to improve or modify the functional and textural properties of investigated food proteins (SC and BP in particular) in comminuted meat products.     

Quality differences between heat-induced gels from farmed gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax)

The effect of farmed fish species (sea bream, Sparus aurata, versus sea bass, Dicentrarchus labrax) on the quality of heat-induced gel products was evaluated. Additionally, the effect of microbial transglutaminase (MTGase) incorporation (0.5%, w/w) into the gels on their quality was also assessed.Both sea bream and sea bass yielded gel products of high quality. The fat content of the gel products attained from sea bass was higher than that of those prepared from sea bream (7.6% vs. 6.1%). Therefore, fat gels prepared with unwashed mince from farmed fish species may present a great potential for the aquaculture sector because, besides adequate gelling ability, these gels have a higher nutritional value than commercial gels, especially given their high eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels. Moreover, MTGase improved textural quality and reduced protein solubility. The gel strength, cohesiveness, and rupture properties of sea bream gels were higher than those of sea bass gels (mainly for gels containing MTGase), thus indicating a higher textural quality. Sea bass proteins were less soluble than sea bream proteins. Different hypothesis were put forward concerning the protein phenomena underlying such differences between the two farmed fish species.     

Novel approaches in improving the quality and safety aspects of processed meat products through high pressure processing technology - A review

BackgroundIn recent years, there has been growing consumer demand for the minimally processed and chemical additives free Ready-To-Eat (RTE) healthier meat products. On the other hand processed and RTE meat products have been notified as the primary cause for food borne outbreaks in different countries that commonly associated with emerging pathogens such as Salmonella, Listeria monocytogenes and Escherichia coli species.Scope and approachHigh pressure processing (HPP) has been renewed as a best non-thermal intervention for extending the shelf-life and safety of RTE meat products without altering the sensory and nutritional properties. Meat products are complex medium with different physical and chemical compositions that influence the lethality of the microorganisms during HPP. Using high pressure levels (above 600 MPa) for complete sterility of meat products may not be economically feasible more over it may negatively affect the product quality characteristics. The present review aimed to explore the recent research investigations addressed the multi hurdle approaches to increase the effectiveness of HPP at lower processing levels in order to reduce the processing costs and to improve the safety and quality of processed meat products.Key findings and conclusionsThe combination of natural antimicrobials (plant bioactive compounds and bacteriocins) and antioxidants (plant phenolic compounds) as additional hurdles through different mechanisms (active and intelligent packaging) during HPP can definitely be an effective and innovative intervention in ensuring the complete safety of processed meat products. Moreover, the development of low salt meat products with optimum quality attributes can be highly possible through HPP technology.     

Varying the temperature of the liquid used for high-pressure processing of prerigor pork: effects on fresh pork quality, myofibrillar protein solubility, and frankfurter textural properties

The objective was to evaluate high-pressure processing (HPP) with varying liquid (water) temperatures on pork quality and textural properties of frankfurters. HPP pressurization liquid temperatures were 15.5 °C (HPP Low) and 29.4 °C (HPP Med). Analyses were conducted using paired boneless loins and paired boneless hams. Loins were evaluated for pH, purge loss, objective color, subjective color, firmness; and changes in color after a bloom period. Eight independent batches (2 batches each of HPP Low, paired untreated, HPP Med, and paired untreated) of frankfurters were manufactured from the outside portion of the ham and the knuckle. Both HPP treatments resulted in higher (P < 0.05) ultimate pH and less (P < 0.05) purge loss of the loin. Loin tenderness was not different among either HPP treatment temperature groups when compared to untreated controls except HPP Med chops were more tender (P = 0.02) than untreated controls. Salt-soluble protein extractability of inside ham muscles was lower (P < 0.05) for both HPP treatment levels when compared to untreated controls, but was not different between the 2 HPP treatment levels. Textural properties of frankfurters were not different for either HPP treatment group when compared to its respective untreated control for any parameter except springiness. HPP Low frankfurters had lower (P = 0.10) springiness values than untreated controls. Fracturability of HPP Med samples was lower (P = 0.12) than untreated controls. Overall, HPP caused higher ultimate pH and increased water-holding capacity, but did not affect tenderness of fresh meat or textural properties of frankfurters. PRACTICAL APPLICATION: HPP can be used on prerigor pork as means to improve fresh pork quality. Loins from HPP-treated pork sides had higher ultimate pH values and less package purge loss. Tenderness values were not affected positively or negatively by HPP treatment. The high pH and water-holding capabilities of treated samples have positive implications for further processing applications. Frankfurter textural properties suggest emulsified products can be made with pressurized pork without sacrifice to the textural profile.     

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.     

High Pressure Treatment Effect on Physicochemical and Nutritional Properties of Fluid Foods During Storage: A Review

Abstract: Consumers demand foods that are easy to consume and that are of high nutritional and sensory quality. Therefore, they appreciate the similarity of minimally processed products to fresh products. In recent years, the food industry has shown increased interest in nonthermal preservation technologies, because they provide products of proven quality and can be an alternative to traditional thermal methods, thus increasing added value. This review examines the effects of high pressure processing (HPP) on the nutritional and physicochemical parameters of fluid foods. While some general trends can be observed, the effects of HPP differ not only according to treatment intensity, but also according to the food matrix, suggesting that each matrix should be studied separately.     

谷氨酰胺转氨酶预交联改善CaSO4诱导大豆分离蛋白凝胶性的研究

酶法改性能够有效提升大豆蛋白的凝胶性。为了探讨谷氨酰胺转氨酶(transglutaminase, TGase)预交联对盐诱导大豆分离蛋白凝胶性的影响,通过控制酶浓度、预交联时间制备不同预交联程度的大豆分离蛋白(soy protein isolate,SPI)溶液,并研究其在CaSO₄作用下的成胶性能。结果显示,与未经TGase处理的SPI相比,TGase适度预交联能够显著提升SPI的凝胶品质。经3～5 U/g TGase预交联20 min或3 U/g TGase预交联20～30 min后,SPI凝胶性得到了不同程度的提升,其中弹性模量、屈服应力、屈服应变、持水率最大分别提高了124.5%、269.0%、135.0%及53.0%。然而,过度预交联产生过大的蛋白聚集体,导致最终形成的凝胶结构粗糙、多孔,凝胶强度、持水力等均显著下降(P<0.05)。由此可见,合理利用TGase对蛋白进行预交联处理能够改善SPI凝胶制品品质,对于TGase在食品工业中的应用及传统豆制品质构改良具有重要的指导意义。