Limited enzymatic proteolysis increases the level of incorporation of canola proteins into mayonnaise

An alkaline extract of canola meal was hydrolyzed using a protease (Proleather FG-F) for 2.5 and 10 min to obtain protein hydrolysates with 7% and 14% degree of hydrolysis (DH), respectively. The protein hydrolysates were used to replace up to 50% (w/w) of egg yolk in a model mayonnaise preparation and the effects on physicochemical properties determined. Unhydrolyzed canola proteins could only be incorporated into mayonnaise up to a maximum 15% (w/w) substitution of egg yolk without emulsion breakdown. At 7% DH, the canola protein could be used to substitute up to 20% (w/w) of egg yolk, while at 14% DH the maximum level of substitution was 50% (w/w). Increased level of canola protein products reduced the whiteness and increased the reddish-brown colour of mayonnaise. Mayonnaise that was stabilized by only egg yolk had the least particle size and highest viscosity when compared to emulsions stabilized by canola proteins. Stability studies showed that most of the mayonnaise preparations retained their physicochemical properties after storage for 4 weeks at 4 °C. The results suggest that limited protein hydrolysis can be used to increase the level of incorporation of globular proteins into mayonnaise preparations.Industrial relevanceModifications to the native structures of plant proteins remain a viable industrial option for improving their functionality in food systems. Therefore, the process described in this work could promote utilization of enzymatically modified canola proteins as suitable ingredients in the formulation of food emulsions.     

New processing of lupin protein isolates and functional properties

A growing demand for functional plant proteins could be identified, which properties are customized for specific applications and formulations as food ingredients. Native lupin proteins (α, β, γ) conglutin have a good solubility at appropriately chosen conditions. A novel procedure has been proposed to maintain the native protein properties. Lupin proteins are extracted from hexane deoiled lupin. The protein product type E comprises high molecular weight proteins (α, β‐conglutin( which are separated using alkaline extraction and acid precipitation procedures. The protein product type F is enriched in the γ‐conglutin fraction and is separated from the acid pre‐extract applying cross flow filtration at pH 7–8. For the zirconium oxide membrane the filtration rate can be increased by appropriately chosen pH conditions up to 70 l/m²h. Lupin protein fraction (type E and F) are highly soluble protein isolates with outstanding emulsification, salt tolerance and foaming properties. These new lupin proteins (type E and F) offer extremely interesting properties for application in food systems and are available from pilot plant fractionation.     

New processing of lupin protein isolates and functional properties.

A growing demand for functional plant proteins could be identified, which properties are customized for specific applications and formulations as food ingredients. Native lupin proteins (alpha, beta, gamma) conglutin have a good solubility at appropriately chosen conditions. A novel procedure has been proposed to maintain the native protein properties. Lupin proteins are extracted from hexane deoiled lupin. The protein product type E comprises high molecular weight proteins (alpha, beta-conglutin), which are separated using alkaline extraction and acid precipitation procedures. The protein product type F is enriched in the gamma-conglutin fraction and is separated from the acid pre-extract applying cross flow filtration at pH 7-8. For the zirconium oxide membrane the filtration rate can be increased by appropriately chosen pH conditions up to 70 l/m2h. Lupin protein fraction (type E and F) are highly soluble protein isolates with outstanding emulsification, salt tolerance and foaming properties. These new lupin proteins (type E and F) offer extremely interesting properties for application in food systems and are available from pilot plant fractionation.     

Pickering emulsions in foods - opportunities and limitations

In order to critically discuss the potential of Pickering-type emulsions in food applications this review provides the theoretical background of the stabilizing mechanisms, the resulting requirements for particles to stabilize these systems and the limitations resulting from these fundamental considerations. Food grade particle systems investigated in the past are presented. It becomes obvious that with a proper choice of a particle type, oil-in-water as well as water-in-oil emulsions can be achieved. For highly viscous products, products with a high internal phase volume and foams Pickering particles offer alternatives to commonly used surfactants. Pickering emulsions might be able to offer new approaches for fat reduction as well as encapsulation and sustained release of active ingredients. Nevertheless, a major part of successful systems have been achieved with silica or modified silica particles, which is not in line with the consumer demand for clean label, natural systems or not even food grade. However, the intriguing possibilities motivate and justify future research on the identification of new suitable ingredients, improvement of existing formulations and identification of new fields of application.     

Modification of plant proteins for improved functionality: A review

The market trend towards plant-based protein has seen a significant increase in the last decade. This trend has been projected to continue in the coming years because of the strong factors of sustainability and less environmental impact associated with the production of plant-based protein compared to animal, aside from other beneficial health claims and changes in consumers' dietary lifestyles. In order to meet market demand, there is a need to have plant-based protein ingredients that rival or have improved quality and functionality compared to the traditional animal protein ingredients they may replace. In this review article, we present a detailed and concise summary of the functionality challenges of some plant protein ingredients with associated physical, chemical, and biological processing techniques (traditional and emerging technologies) that have been attempted to enhance them. We cataloged the differences between several studies that seek to address the functionality challenges of selected plant-based protein ingredients without overtly commenting on a general technique that addresses the functionality of all plant-based protein ingredients. Additionally, we elucidated the chemistry behind some of these processing techniques and how they modify the protein structure for improved functionality. Although, many food industries are shifting away from chemical modification of proteins because of the demand for clean label product and the challenge of toxicity associated with scale-up of this technique, so physical and biological techniques are widely being adopted to produce a functional ingredient such as texturized vegetable proteins, hydrolyzed vegetable protein, clean label protein concentrates, de-flavored protein isolates, protein flour, and grits.     

Effects of replacing soybean meal with raw or extruded blends containing faba bean or lupin seeds on nitrogen metabolism and performance of dairy cows

The objective was to test the effects of replacing soybean meal in dairy cow diets with either raw or extruded faba bean:linseed or lupin:linseed blends on intake, milk yield and composition, N partitioning, and ruminal and plasma parameters. Our main hypotheses were that N from extruded blends was less degradable in the rumen than N from raw seeds, and that a higher extrusion temperature favored ruminal protection of proteins and milk protein yield, and lowered urinary N excretion. Eight Holstein cows fitted with ruminal cannulas were used in two 4 × 4 Latin square design experiments conducted in parallel. In both experiments, cows were fed diets with a crude protein content of 14.6%, containing 60% of forage (dry matter basis). Treatments differed by the composition of the concentrates: control in both experiments was based on soybean meal, and experimental treatments were based on proteaginous:linseed (90:10%) blends consisting of faba bean blends (first experiment) or lupin blends (second experiment) presented either raw, extruded at 140°C, or extruded at 160°C. Intake, milk yield and composition, ruminal pH, volatile fatty acids and ammonia kinetics, digestibility, N partitioning, Maillard compounds in feed and feces, plasma AA, and ¹⁵N natural enrichment were measured. Data were analyzed using ANOVA according to the MIXED procedure of SAS (version 9.4, SAS Institute Inc., Cary, NC). Ammonia content in ruminal fluid did not significantly change when soybean meal was replaced by either raw or extruded faba bean, but tended to be higher with lupin. Milk yield was increased by 2.6 kg with faba bean blend extruded at 140°C compared with faba bean blend extruded at 160°C. Milk fat and milk protein concentrations were decreased by 3.1 and 2.3 g/kg, respectively, with lupin blends compared with soybean meal. Nitrogen partitioning between milk, feces, and urine did not change. Nitrogen apparent digestibility decreased by 3 g/100 g of N between faba bean blend extruded at low and at high temperatures. The content of Maillard compounds in feces was higher with blends extruded at 160°C than with raw or extruded at 140°C blends within both experiments. Total plasma AA tended to be higher with extruded blends than with raw in the faba bean experiment. Both extrusion temperatures appeared to protect dietary proteins from ruminal degradability, but proteins seemed to be overprotected at 160°C.     

Immunodetection of legume proteins resistant to small intestinal digestion in weaned piglets

Experiments were conducted to investigate the biochemistry of digestion of the major storage proteins from soya bean, pea, faba bean, blue lupin, and chickpea seeds in the ileum of piglets. Hyperimmune plasmas against the crude protein extracts and the purified 11S and 7S globulin fractions of each legume seed and an anti‐pea albumin PA2 and lectin antibody were used. They served to probe immunoblots of feed protein extracts and ileal digesta samples. Globally, the recognition by plasmas of intact or partially digested proteins in ileal digesta was rather faint, in agreement with the fairly high in vivo digestibility data obtained with these legume seed proteins. Nevertheless, immunoreactive polypeptides found in digesta of piglets fed pea, faba bean and chickpea belonged mainly to proteins of the 7S family, and to other proteins including low‐molecular weight components such as PA2 albumin and lectin in the case of pea. In piglets fed lupin, nearly intact polypeptides from the 11S family were detected. To conclude, the present immunochemical study conducted on ileal digesta of piglets revealed a few dietary legume proteins of the vicilin and albumin families. Legumin proteins were demonstrated unequivocally in the case of lupin and white chickpea. Copyright © 2003 Society of Chemical Industry     

Effects of composition and processing variables on the oxidative stability of protein-based and oil-in-water food emulsions

Because many common foods are emulsions (mayonnaise, coffee creamers, salad dressing, etc.), a better understanding of lipid oxidation mechanisms in these systems is crucial for the formulation, production, and storage of the relevant consumer products. A research body has focused on the microstructural and oxidative stability of protein-stabilized oil-in-water emulsions that are structurally similar to innovative products that have been recently developed by the food industry (e.g., non-dairy creams, vegetable fat spreads, etc.) This review presents recent findings about the factors that determine the development of lipid oxidation in emulsions where proteins constitute the stabilizing interface. Emphasis is given to “endogenous” factors, such as those of compositional (e.g., protein/lipid phases, pH, presence of transition metals) or processing (e.g., temperature, droplet size) nature. Improved knowledge of the conditions that favor the oxidative protection of protein in emulsions can lead to their optimized use as food ingredients and thereby improve the organoleptic and nutritional value of the related products.     

Aspects of milk-protein-stabilised emulsions

Milk proteins are widely used as ingredients in prepared foods, in which they perform a wide range of key functions, including emulsification, thickening, gelling and foaming. An important functionality of milk proteins in food colloids is their ability to facilitate the formation and stabilisation of oil droplets in emulsions. The ability of milk proteins to adsorb at the oil–water interface and to stabilise emulsions has been exploited by the food industry in the manufacture of nutritional products, specialised medical foods, dietary formulations, cream liqueurs and dairy desserts. This article provides an overview of the properties and functionalities of food emulsions formed with milk proteins, focusing on the structure and composition of adsorbed protein layers, competition between proteins and the physical and chemical stability of emulsion droplets. Of particular importance is the understanding of the behaviour of milk-protein-based emulsions under the conditions relevant to digestion in the human gastrointestinal tract. Recent relevant research in this area is reviewed and discussed.     

右旋糖酐/蚕豆蛋白复合凝胶的流变特性

为研究乳酸菌右旋糖酐对蚕豆蛋白食品相关性质的影响，采用哈克流变仪和质构仪等测定了添加不同浓度右旋糖酐时GDL诱导的酸致蚕豆蛋白复合凝胶质构和流变特性等指标。结果表明：添加右旋糖酐能显著增加蚕豆蛋白凝胶保水性，空白组蚕豆蛋白凝胶保水性为60.38%，1%右旋糖酐与蚕豆蛋白形成的复合凝胶保水性为70.08%（p<0.05）；右旋糖酐浓度在0.25%~1%之间，对复合蛋白凝胶色泽有一定影响；0.5%右旋糖酐与蚕豆蛋白形成的复合凝胶强度为0.27 N，与空白组蚕豆蛋白凝胶（0.37 N）差异显著，可软化含高蚕豆蛋白食品质构特性；右旋糖酐/蚕豆蛋白复合凝胶流动曲线符合carreau模型（R2>0.99），具有假塑性流体的特性；应变扫描的弹性模量G''均高于黏性模量G''，说明右旋糖酐/蚕豆蛋白复合凝胶的弹性占主导；频率扫描结果显示添加右旋糖酐可软化蚕豆蛋白凝胶，使凝胶G''、G''降低，更易于加工。在蚕豆食品中添加右旋糖酐可改善蚕豆蛋白的质构和流变特性，为拓展其应用范围提供参考。     

Application of immunochemical determination methods in foreign protein analysis. 1. Determination and identification of faba bean protein isolate by means of the rocket technic on cellulose acetate film and countercurrent immunoelectrophoresis

The present work deals with the applicability of the Rocket technique on cellulose acetate film and of the countercurrent immunoelectrophoresis for identification or determination of faba bean protein in model foods. It was found that both the methods are suitable for a rapid and uncomplicated determination or identification of faba bean protein in not heat-denaturized food. Cross reactivities occur with other leguminous proteins existing in the samples, effects of which add with those of the faba bean protein additive if the Rocket technique is used. With determination of faba protein by means of the Rocket-technique on cellulose acetate film coefficients of variation of about 20% are obtained.     

Low methoxy pectin/protein interaction in o/w emulsions - Effects of acetylated faba bean globulin

The addition of low methoxy pectin to maximal acetylated faba bean globulin in o/w emulsion leads in the pH range between 5.5 and 6.5 to an increased protein content in the protein film around the oil droplets. This effect is accompanied with a rise of the apparent viscosity and flow behaviour index of the emulsions. In agreement with these modifications increased emulsion stability against creaming is found.     

Effect of glycerol on the physicochemical properties of films based on legume protein concentrates: A comparative study

The overall goal of this research was to examine the mechanical, water vapor barrier properties and opacity of films prepared using legume protein concentrates (faba bean, pea, lupin, lentil, and soy) as a function of glycerol concentration (50, 75, or 100% [wt/wt]—relative to the protein weight). Overall, tensile strength (TS) decreased with increasing glycerol concentration, whereas tensile elongation (TE) and water vapor permeability (WVP) increased with increasing glycerol concentration. Film opacity was independent of glycerol concentration. The effect of protein‐type varied considerably depending on the functional property of the film being measured; TS was greatest with faba bean and lowest with lupin, whereas TE was highest for pea, and lowest for soy. Lentil protein films had considerably higher WVP, at the 100% glycerol concentration, as compared to the other protein concentrates. Findings from this study indicate that legume protein concentrates are capable of forming biodegradable, edible films. Overall, pea protein concentrate films showed the most promise for application in terms of strength, elongation, and moisture barrier properties.     

Short communication: Milk fat globule membrane as a potential delivery system for liposoluble nutrients

A soft physical process was used to extract and purified bovine milk fat globule membrane (MFGM) fractions on a pilot scale. Oil-in-water emulsions enriched with α-tocopherol and lycopene were then prepared and stabilized with the extracted MFGM fraction and conventional milk protein concentrates (i.e., whey proteins, caseinate). A protocol of in vitro digestion was set up to evaluate the bioaccessibility of the tocopherol and lycopene in the different emulsions. Bioaccessibility was defined as the capacity of liposoluble compounds to be transferred into mixed micelles formed during the digestion process. Results showed that the accumulation of the tocopherol and lycopene into mixed micelles in MFGM-stabilized emulsions was around 2-fold greater than in emulsions stabilized with conventional milk proteins. This result confirms the potential use of MFGM-enriched ingredients as delivery systems of liposoluble nutrients in food formulations.     

Emulsification mechanisms and characterizations of cold, gel-like emulsions produced from texturized whey protein concentrate

A novel supercritical fluid extrusion (SCFX) process was used to successfully texturize whey protein concentrate (WPC) into a product with cold-setting gel characteristics that was stable over a wide range of temperature. It was further hypothesized that incorporation of texturized WPC (tWPC) within an aqueous phase could improve emulsion stability and enhance the rheological properties of cold, gel-like emulsions. The emulsifying activity and emulsion stability indices of tWPC and its ability to prevent coalescence of oil-in-water (o/w) emulsions were evaluated and compared with the commercial WPC80. The cold, gel-like emulsions were prepared at different oil fractions (φ = 0.20–0.80) by mixing oil with the 20% (w/w) tWPC dispersion at 25 °C and evaluated using a range of rheological techniques. Microscopic structure of cold, gel-like emulsions was also observed by Confocal Laser Scanning Microscope (CLSM). The results revealed that the tWPC showed excellent emulsifying properties compared to the commercial WPC in slowing down emulsion breaking mechanisms such as creaming and coalescence. Very stable with finely dispersed fat droplets, and homogeneous o/w gel-like emulsions could be produced. Steady shear viscosity and complex viscosity were well correlated using the generalized Cox–Merz rule. Emulsions with higher viscosity and elasticity were obtained by raising the oil fraction. Only 4% (w/w) tWPC was needed to emulsify 80% (w/w) oil with long-term storage stability. The emulsion products showed a higher thermal stability upon heating to 85 °C and could be used as an alternative to concentrated o/w emulsions and in food formulations containing heat-sensitive ingredients.     

Development of a real-time PCR method for the simultaneous detection of soya and lupin mitochondrial DNA as markers for the presence of allergens in processed food

Lupin and soya are members of the Leguminosae family which are recognised as some of the richest source of vegetable proteins. Lupin- and soya-containing products are available on the EU market and could cause severe adverse reactions in allergic individuals, even if consumed at low concentrations. In this context the development of methods for reliable detection of these allergens in food products is a useful tool for the surveillance of established legislation on food labelling within the EU. This work described the development of a duplex real-time PCR method allowing the simultaneous detection of traces of lupin and soya in processed food based on a specific TaqMan® probe designed on a mitochondrial tRNA-MET gene. A set of primers and probes was designed for the amplification of a 168 and 175 bp fragment of lupin and soya mitochondrial DNA, respectively. The performance of the method was established using lupin and soya flours and cookies baked from lupin- and soya-containing dough (different concentrations and baking times). The PCR platform yielded consistent and repeatable results. The specificity of the system was tested with DNA from 28 plant species. The sensitivity of the method was suitable to detect allergenic ingredients in the low mg per kg range. Both lupin and soya at a level of 2.5 mg per kg food matrix could be detected in cookies baked at 180 °C for 10 min. The method was successfully applied to bakery (e.g. bread) and vegetarian (e.g. non-meat sausages) food products that contain or may contain soya and/or lupin as ingredient or contaminant (according to the declaration on the product label).     

Physicochemical properties and issues associated with trypsin hydrolyses of bovine casein-dominant protein ingredients

Milk protein concentrate (MPC) and sodium caseinate (NaCas) were hydrolysed using the enzyme trypsin and the subsequent physical properties of the two ingredients were examined. Trypsin hydrolysis was carried out at pH 7 and at 45 °C on 11.1% (w/w) protein solutions. Heat inactivation of trypsin was carried out when the degree of hydrolysis reached either 10 or 15%. Size-exclusion chromatography and electrophoresis confirmed a significant reduction in protein molecular weight in both ingredients. However, whey proteins in MPC were more resistant to trypsin hydrolysis than casein. Oil-in-water emulsions were prepared using intact or hydrolysed protein, maltodextrin, and sunflower oil. Protein hydrolysis had a negative effect on the subsequent physical properties of emulsions, compared with non-hydrolysed proteins, with a larger particle size (only for NaCas stabilised emulsions), faster creaming rate, lower heat stability, and increased sedimentation observed in hydrolysed protein emulsions.     

Parameters for the evaluation of the thermal damage and nutraceutical potential of lupin-based ingredients and food products

Foods based on sweet lupin proteins are gaining attention from industry and consumers because of their possible role in the prevention of cardiovascular disease. When promoting lupin-based foods for inclusion in a daily diet, the thermal damage suffered during processing is of relevance to the bioactive and nutritional quality of the food product. N-(2-furoylmethyl)-L-lysine (furosine) quantification demonstrates that currently available sweet lupin protein isolates have a thermal damage comparable to or lower than other traditional food ingredients, and are a good source of lysine in non-dairy products. In lupin-based foods claiming to have cholesterol-lowering potential, shotgun proteomics offers itself as a fast and effective screening method for assessing the biological availability of active peptides. Such a method is readily applicable to other legume-enriched food products.     

Emulsifying Properties of Legume Proteins Compared to β‐Lactoglobulin and Tween 20 and the Volatile Release from Oil‐in‐Water Emulsions

The emulsifying properties of plant legume protein isolates (soy, pea, and lupin) were compared to a milk whey protein, β‐lactoglobulin (β‐lg), and a nonionic surfactant (Tween 20). The protein fractional composition was characterized using sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis. The following emulsion properties were measured: particle diameter, shear surface ζ‐potential, interfacial tension (IT), and creaming velocity. The effect of protein preheat treatment (90 °C for 10 min) on the emulsifying behavior and the release of selected volatile organic compounds (VOCs) from emulsions under oral conditions was also investigated in real time using proton transfer reaction‐mass spectrometry. The legume proteins showed comparable results to β‐lg and Tween 20, forming stable, negatively charged emulsions with particle diameter d_3,2 < 0.4 μm, and maintained stability over 50 d. The relatively lower stability of lupin emulsions was significantly correlated with the low protein surface hydrophobicity and IT of the emulsion. After heating the proteins, the droplet size of pea and lupin emulsions decreased. The VOC release profile was similar between the protein‐stabilized emulsions, and greater retention was observed for Tween 20‐stabilized emulsions. This study demonstrates the potential application of legume proteins as alternative emulsifiers to milk proteins in emulsion products.