Membrane filtration technologies have shown great potential as a gentle and effective method for concentrating and fractionating proteins for food applications. However, the application of this technology to plant-derived protein streams is in its infancy. In this study, an aqueous rapeseed protein concentrate was obtained with wet milling, and its performance during ultrafiltration with two distinct molecular weight cut-offs (10 and 100 kDa) was tested. All rapeseed proteins were retained during filtration. The addition of pectinase during extraction prior to filtration caused important structural modifications to the extract, resulting in increased permeate fluxes, increased carbohydrate permeation and a reduction in irreversible fouling. Lager pore sizes led to more pronounced fouling. FTIR analysis of the spent membranes showed that proteins and lipids are causing irreversible fouling.

This study aims to investigate the influence of alkaline treatment duration (0-5 h) on the physicochemical properties and emulsifying performance of rapeseed protein during pH-shift process. Results showed that a 4-h alkaline treatment significantly reduced the particle size of rapeseed protein and led to a notable decrease in disulfide bond content, as well as alterations in subunit composition. Moreover, solubility of rapeseed protein increased from 18.10 ± 0.13% to 40.44 ± 1.74% post-treatment, accompanied by a ∼ 40% enhancement in emulsifying properties. Morphological analysis revealed superior plasticity and sharper contours in 4-h alkali-treated rapeseed protein emulsions compared to untreated counterparts. Rheological analysis indicated higher viscosity and elasticity in the alkali-treated group. Overall, 4-h alkaline treatment markedly enhanced the multifaceted functional attributes of rapeseed protein during pH-shift process, rendering it a promising emulsifier in the food industry.

To improve the techno-functional properties of rapeseed protein (RP), this work tried to regulate the molecular structure of RP via inducing the co-assembly of RP with zein and whey protein (WP). The results showed that WP and zein mainly regulate the folding process of RP through hydrophobic and disulfide bonds, thereby altering the structural conformation and forming stable complex RP (CRP). WP addition not only increased the number of surface charges and hydrophilicity of proteins, but also decreased their sizes, improved the water solubility, as well as the availability of active groups. These changes significantly increased the foaming capacity (from 60 % to 147 %) and in vitro gastric digestion rate (from 10 % to 60 %) of CRP. Besides, WP also contributed to the formation of gels and the regulation of their textural profiles. Comparatively, zein improved the hydrophobicity of CRP and balanced degree of intermolecular forces, which effectively increased the emulsifying activity index of CRP from 22 m2/g to 90 m2/g. Zein decreased the hardness, springiness and water-holding capacity of gel, but increased its gumminess and chewiness. Overall, both WP and zein effectively changed the structural conformation of RP, and improved its techno-functional properties, which provides an effective strategy to modify protein.

Our previous experiments found that rapeseed protein (RP) has applicability in low-moisture textured proteins. The amount of RP added is limited to <20 %, but the addition of 20 % RP still brings some negative effects. Therefore, in order to improve the quality of 20%RP textured protein, this experiment added different proportions of sodium tripolyphosphate (STPP) to improve the quality of the product, and studied the physical-chemical properties and molecular structure changes of the product to explore the possible modification mechanism. The STPP not only improved the expansion characteristics of extrudates, but also increased the brightness of the extrudates, the rehydration rate. In addition, STPP increased the specific mechanical energy during extrusion, decreased the material mass flow rate. Furthermore, STPP decreased the starch digestibility, increased the content of slow-digesting starch and resistant starch. STPP increased the degree of denaturation of extrudate proteins, the proportion of β-sheets in the secondary structure of proteins, as well as the intermolecular hydrogen bonding interactions. The gelatinization degradation degree of starch molecules also decreased with the addition of STPP. STPP also increased the protein-starch interactions and enhanced the thermal stability of the extrudate. All these indicate that STPP can improve the physical-chemical properties of extrudate.

This study aimed to modify the sensory properties of rapeseed protein concentrate using a combination of fermentation and high-moisture extrusion processing for producing meat analogues. The fermentation was carried out with Lactiplantibacillus plantarum and Weissella confusa strains, known for their flavour and structure-enhancing properties. Contrary to expectations, the sensory evaluation revealed that the fermentation induced bitterness and disrupted the fibrous structure formation ability due to the generation of short peptides. On the other hand, fermentation removed the intensive off-odour and flavour notes present in the native raw material. Several control treatments were produced to understand the reasons behind the hindered fibrous structure formation and induced bitterness. The results obtained from peptidomics, free amino ends, and solubility analyses strongly indicated that the proteins were hydrolysed by endoproteases activated during the fermentation process. Furthermore, it was suspected that the proteins and/or peptides formed complexes with other components, such as hydrolysis products of glucosinolates and polysaccharides.

Rapeseed cake serves as a by-product in the oil extraction industry, characterized by its elevated protein content. However, the presence of antinutritional factors limits the utilization of rapeseed cake as a viable protein source. In this study, different doses of γ-irradiation were used to irradiate rapeseed cake and rapeseed protein isolate was extracted through a modified alkaline solution and acid precipitation method from rapeseed cake. The chemical composition and in vivo acute toxicity of rapeseed protein isolate were determined. The protein recovery rate of rapeseed protein isolate was 39.08 ± 3.01% after irradiation, while the content of antinutritional factors was significantly reduced. Moreover, γ-irradiation did not have any experimentally related effects on clinical observations or clinicopathology in mice. Overall, the reduced antinutrients and increased functional properties suggest that the irradiation of rapeseed cake (<9 kGy) could be utilized as a pre-treatment in the development of rapeseed cake-based value-added protein products.

OBJECTIVE: Two major protein families are present in rapeseed, namely cruciferins and napins. The structural differences between the two protein families indicate that they might behave differently when their mixture stabilises oil-water interfaces. Therefore, this work focuses on elucidating the role of both proteins in interface and emulsion stabilisation.
METHODS: Protein molecular properties were evaluated, using SEC, DSC, CD, and hydrophobicity analysis. The oil-water interface mechanical properties were studied using LAOS and LAOD. General stress decomposition (GSD) was used as a novel method to characterise the nonlinear response. Additionally, to evaluate the emulsifying properties of the rapeseed proteins, emulsions were prepared using pure napins or cruciferin and also their mixtures at 1:3, 1:1 and 3:1 (w:w) ratios.
RESULTS: Cruciferins formed stiff viscoelastic solid-like interfacial layers (Gs\' = 0.046 mN/m; Ed\' = 30.1 mN/m), while napin formed weaker and more stretchable layers at the oil-water interface (Gs\' = 0.010 mN/m; Ed\' = 26.4 mN/m). As a result, cruciferin-formed oil droplets with much higher stability against coalescence (coalescence index, CI up to 10%) than napin-stabilised ones (CI up to 146%) during two months of storage. Both proteins have a different role in emulsions produced with napin-cruciferin mixtures, where cruciferin provides high coalescence stability, while napin induces flocculation. Our work showed the role of each rapeseed protein in liquid-liquid multiphase systems.

Canola is the second-largest cultivated oilseed crop in the world and produces meal consisting of about 35-40% proteins. Despite this, less than 1% of the global plant-based protein market is taken up by canola protein. The reason behind such underutilization of canola protein and its rapeseed counterpart could be the harsh conditions of the industrial oil extraction process, the dark colour of the meal, the presence of various antinutrients, the variability in the protein composition based on the source, and the different properties of the two major protein components. Although academic research has shown immense potential for the use of canola protein and its rapeseed counterpart in emulsion development and stabilization, there is still a vast knowledge gap in efficiently utilizing canola proteins as an effective emulsifier in the development of various emulsion-based foods and beverages. In this context, this review paper summarizes the last 15 years of research on canola and rapeseed proteins as food emulsifiers. It discusses the protein extraction methods, modifications made to improve emulsification, emulsion composition, preparation protocols, and emulsion stability results. The need for further improvement in the scope of the research and reducing the knowledge gap is also highlighted, which could be useful for the food industry to rationally select canola proteins and optimize the processing parameters to obtain products with desirable attributes.

The objective of this study was to extract the rapeseed protein from by-products and further examine the effect of lab-made rapeseed protein on the droplet size, microstructure, colour, encapsulation and apparent viscosity of emulsions. Rapeseed protein-stabilised emulsions with an increasing gradient of milk fat or rapeseed oil (10, 20, 30, 40 and 50%, v/v) were fabricated using a high shear rate homogenisation. All emulsions showed 100% oil encapsulation for 30 days of storage, irrespective of lipid type and the concentration used. Rapeseed oil emulsions were stable against coalescence, whereas the milk fat emulsion showed a partial micro-coalescence. The apparent viscosity of emulsions raised with increased lipid concentrations. Each of the emulsions showed a shear thinning behaviour, a typical behaviour of non-Newtonian fluids. The average droplet size was raised in milk fat and rapeseed oil emulsions when the concentration of lipids increased. A simple approach to manufacturing stable emulsions offers a feasible hint to convert protein-rich by-products into a valuable carrier of saturated or unsaturated lipids for the design of foods with a targeted lipid profile.

Compared with the complexity of chemical methods, near-infrared spectroscopy (NIRS) is widely used in the detection of protein content because of its advantages of being fast and non-destructive. Aiming to tackle the problem that the raw near-infrared spectroscopy contains many redundant wavelengths, which affects the accuracy of quantitative prediction and requires expertise to process, we propose an end-to-end network: Band Reweighted Network (BR-Net) that automates wavelength reweighted and quantitative prediction of protein content in rapeseed. Unlike extracting part of wavelengths by the traditional wavelength selection methods, BR-Net retains all spectral wavelengths and assigns different weights to the wavelengths to express the correlation with the corresponding concentration, which enables wavelength selection without ignoring the information contained in the less relevant wavelengths. We compare BR-Net with traditional selection methods such as SPA, LARS, CARS, and UVE to verify its efficiency and robustness, finding that the R2 of the training set and test set are 0.9797 and 0.9215, the RMSEC and RMSEP are 0.4053 and 0.8501, respectively, and the RPD is 3.5686, which prove BR-Net outperforms all the traditional methods. The network described here is universally applicable to a variety of NIR quantitative analyses.