Application of legumes in plant-based milk alternatives: a review of limitations and solutions.

In recent years, a global shift has been observed toward reducing the consumption of animal-derived foods in favor of healthier and more sustainable dietary choices. This has led to a steady growth in the market for plant-based milk alternatives (PBMAs). Projections suggest that this market will reach a value of USD 69.8 billion by 2030. Legumes, being traditional and nutritious ingredients for PMBAs, are rich in proteins, dietary fibers, and other nutrients, with potential health benefits such as anticancer and cardiovascular disease prevention. In this review, the application of 12 legumes in plant-based milk alternatives was thoroughly discussed for the first time. However, compared to milk, processing of legume-based beverages can lead to deficiencies such as nutritional imbalance, off-flavor, and emulsion stratification. Considering the potential and challenges associated with legume-based beverages, this review aims to provide a scientific comparison between legume-based beverages and cow's milk in terms of nutritional quality, organoleptic attributes and stability, and to summarize ways to improve the deficiencies of legume-based beverages in terms of raw materials and processing method improvements. In conclusion, the legume-based beverage industry will be better enhanced and developed by improving the issues.

The Composition Optimization of Curcumin-Loaded Double Oil-Water-Oil Emulsions and Their Stability Evaluation.

This study aimed to optimize the preparation of multiple oil-water-oil (O/W/O) emulsions using varying amounts of Tween 20 emulsifier, different homogenization methods, and optimal preparation temperatures as carriers for encapsulated curcumin. Following the optimization process, the optimal preparation temperature was found to be 25 °C, with a homogenization speed of 10,000 RPM and an emulsifier concentration of 0.5% Tween 20. Subsequently, the effects of physicochemical and viscoelastic properties on the different types of oils used in the outer phase, as well as the impact of storage time, were monitored. The novelty of this work lies in its comprehensive analysis of the stability and encapsulation efficiency of multiple emulsions using various oils, an area that has not been extensively explored before. After identifying the optimal preparation procedure, all samples with different edible oils demonstrated excellent stability and encapsulation efficiency, showing minimal variation in results. The most stable multiple emulsion was found to be the one with coconut oil in the outer phase, exhibiting half the particle size compared to other samples and the lowest encapsulation efficiency losses over 50 days of storage. This study provides new insights into the formulation of stable multiple emulsions for the effective delivery of curcumin and similar bioactive compounds.

Desmodium intortum (Mill.) Urb. Protein Isolate Aggregates as Pickering Stabilizers: Physicochemical Characteristics and Emulsifying Properties.

This work aimed to investigate the feasibility of fabricating Pickering emulsions stabilized by Desmodium intortum protein isolate (DIPI) aggregates. The DIPI aggregates were formed using heat treatment, and the effects of ionic strength and pH on their properties were investigated. The heat-treated protein exposes its hydrophobic groups due to structural damage, resulting in rapid aggregation of the protein into aggregates with a size of 236 nm. The results showed that the aggregates induced by ionic strength had larger particle size and higher surface hydrophobicity and partial wettability. Moreover, this study explored effective strategies for bolstering Pickering emulsion stability through optimized DIPI aggregate concentration (c) and oil fraction (ø). The DIPI Pickering emulsion (DIPIPE) formed at c = 5% and ø = 0.7 was still highly stable after 30 days of storage. As confirmed by laser confocal microscopy, DIPI aggregates could be adsorbed onto the oil-water interface to form a network structure that could trap oil droplets in the network. Collectively, the Pickering emulsion stabilized by DIPI aggregates exhibited excellent stability, which not only deeply utilizes the low-value protein resources in the Desmodium intortum for the first time, but also demonstrates the potential of DIPI for the bio-based field.

Acid-induced conformation regulation of peanut polysaccharide and its effect on stability and digestibility of oil-in-water emulsion.

BACKGROUND: Developing the stable and healthy emulsion-based food is in accord with the needs of people for health. In the present study, acidification at pH 3.0 of peanut polysaccharide (APPSI) was employed to regulate its conformation and further improve its advantages in preparing oil-in-water emulsion. RESULTS: The results indicated that acidification induced conversion of PPSI aggregates into linear chains. Increasing concentration promoted formation of cross-linked network structure shown in transmission electron microscopy images. Consequently, the viscosity, yield stress, storage modulus and flow activation energy significantly increased, further fabricating gel structure. Moreover, aggregation behavior suggested that more exposed proteins were involved in gel structure, thereby forming many hydrophobic cores as verified by fluorescence spectroscopy of pyrene. Afterwards, emulsion characteristics indicated that APPSI produced strong and thick steric hindrance around oil droplets and the coil-like interweaved chains locked the continuous phase, bringing strong elasticity and resistance to stress and creaming. Meanwhile, the lower fatty acid in APPSI-emulsion was released after simulated gastrointestinal digestion, mainly as a result of the high retention ratio of emulsion droplets. Furthermore, the elastic and viscous Lissajous curves suggested that the structure strength of APPSI-emulsion was similar to that of the salad dressing within the strain 53.22%. CONCLUSION: The conformation of PPSI after acidification at pH 3.0 was suitable for preparing the stable emulsion. The obtained emulsion could resist digestion and maintain a strong structure, comprising a cholesterol-free and low-fat salad dressing substitute. © 2023 Society of Chemical Industry.

Effect of processing (cutter versus continuous emulsifier) and sodium reduction on the physicochemical properties of bologna sausages.

BACKGROUND: Overcoming the impact of sodium reduction in the properties of emulsified sausages is a current challenge in the production of healthier meat products. Because the emulsifying process play a key role in the stability of sausages, the present study aimed to evaluate the effects of two mechanical emulsifying systems (cutter versus continuous emulsifier) and two levels of sodium chloride (2.50 and 1.25%) on the physicochemical characteristics of bologna sausages. RESULTS: A reduction of sodium increased the L* value and reduced the a* value, and also decreased the protein extraction yield in sausages produced in the cutter system. Moreover, the emulsion stability of reduced sodium batter was increased by cutter emulsification (F50C). On the other hand, the continuous emulsifier process did not decrease the extraction of myofibrillar proteins in F50E (sodium reduced treatment), resulting in minimal impact on emulsion stability and an increase in hardness in reduced-sodium sausages. CONCLUSION: Therefore, to produce low-sodium sausages, the continuous emulsifier was more effective producing batters with increased extracted myofibrillar proteins, improving the structure and functionality of myofibrillar proteins compared to the cutter process. © 2023 Society of Chemical Industry.

Effect of synergism of sucrose ester and xanthan gum on the stability of walnut milk.

BACKGROUND: Single emulsifiers have an effect on the stability of plant protein drinks, giving some improvement. Emulsifiers are more effective in maintaining emulsion stability when combined with polysaccharides such as xanthan gum. In this paper, we studied the food-grade emulsifier sucrose ester and measured the average particle size, polydispersity value, zeta potential, microrheological properties, microstructure and creaming index related to walnut protein emulsion by constructing a walnut protein emulsion simulation system. SDS-PAGE and low-field NMR were used to analyze the relative molecular masses of emulsions and the water distribution of emulsions, respectively, to further investigate the synergistic effects of sucrose esters and xanthan gum on the ease of emulsification and intrinsic mechanisms of different molecular weight proteins of walnut protein emulsions. RESULTS: The results indicate that the synergistic effect of sucrose esters and xanthan gum was to stabilize emulsions better than single emulsifiers. Xanthan gum and protein may form protein-polysaccharide complexes, as well as the hydrophobic interaction between sucrose ester and xanthan gum. The properties of xanthan gum can improve the stability of the emulsion by affecting the mechanical properties of walnut protein emulsion, and the combination of sucrose ester and xanthan gum can better stabilize large protein molecules. CONCLUSION: The results not only provide a theoretical basis for the stability of plant protein emulsion systems, but also provide technical support for the production and processing of large-molecule plant proteins into emulsions in this field for improving their stability, and also provide more possibilities for other types of emulsions. © 2023 Society of Chemical Industry.

Understanding the synergistic effect of pea protein and rice bran protein interaction in stabilizing palm kernel oil-in-water emulsion assisted by high-pressure homogenization.

BACKGROUND: Plant-based beverages have recently seen a significant increase in market demand. However, many of these products suffer from poor emulsion stability and low protein content. Gums have commonly been used to enhance emulsion stability but they do not improve the amino acid profile. This study investigated the use of multiples plant proteins to enhance both the stability and nutritional value of plant-based beverages. RESULT: Pea and rice bran proteins both enhanced emulsion stability. Pea protein enhanced the viscosity of the continuous phase whereas rice bran protein lowered interfacial tension. When applied synergistically, competitive adhesion occurred. Rice bran protein gradually displaced pea protein from the oil droplet surface as its concentration increased, leading to emulsion destabilization due to the displaced pea protein. The use of high-pressure homogenization further enhanced the stability of the emulsion by unfolding protein partially. However, increasing homogenization pressure (>500 Bar) and homogenization cycle (>2 cycles) led to protein aggregation due to excessive exposure of its hydrophobic core. The emulsion formed was resistant to coalescence at 4 °C for 28 days and was stable under high pH and low ionic conditions. CONCLUSION: The synergistic combination of plant proteins and the effective utilization of co-processing (homogenization) can enhance the functionality of the individual proteins significantly, leading to the formation of a stable emulsion. The use of plant protein mixture as a stabilizer not only improved the emulsion stability but also ensured a plant-based beverage with a complete amino acid profile for the vegan community. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of Flammulina velutipes powder on the emulsion properties of chicken myofibrillar protein under low-salt conditions.

This study aimed to investigate the influence of varying concentrations of Flammulina velutipes powder (FVP) (0, 4, 8, 12, 16, and 20 g L-1, based on FVP weight per liter of emulsion) on the stability, rheological properties, microstructure, and interfacial protein content of chicken myofibrillar protein (MP) emulsions under low-salt conditions. Visual assessment and the Turbiscan stability index revealed that the stability of MP emulsions improved with increasing FVP concentration. The greatest stability was achieved when the FVP concentration was 16 gL-1. The incorporation of FVP enhanced the elasticity and viscosity of the emulsions by forming a dense three-dimensional network structure. The droplet size of the emulsions initially decreased and then increased with increasing FVP concentration. The addition of FVP increased the amount of protein absorbed by the emulsion layer. Flammulina velutipes powder is promising as a stabilizer that could improve the emulsifying and functional properties of low-salt myofibrillar protein emulsions. © 2024 Society of Chemical Industry.

Preparation and characterization of a new food-grade Pickering emulsion stabilized by mulberry-leaf protein nanoparticles.

BACKGROUND: Food-grade Pickering particles, particularly plant proteins, have attracted significant interest due to their bio-based nature, environmental friendliness, and edibility. Mulberry-leaf protein (MLP) is a high-quality protein with rich nutritional value and important functional properties. It has special amphoteric and emulsifying characteristics, making it valuable for use in Pickering emulsions. This study aimed to investigate the feasibility of using MLP nanoparticles as solid particles to stabilize Pickering emulsions. RESULTS: The particle size of MLP nanoparticles was less than 300 nm under neutral and alkaline conditions. At pH 9, the zeta potential value reached -34.3 mV, indicating the electrostatic stability of the particles. As ion concentration increased, the particle size of MLP nanoparticles increased, and the zeta potential decreased. Throughout the storage process, no obvious aggregation or precipitation was observed in the dispersion of MLP nanoparticles, indicating strong stability. The particle size of the Pickering emulsion decreased with the increase in protein concentration. When the protein concentration was low, the particles on the oil-water interface became sparse, resulting in poor stability of the prepared emulsion and making it susceptible to aggregation and thus larger particle sizes. Increasing the oil-phase ratio to 70% (v/v) promotes the formation of Pickering emulsions, which exhibit exceptional stability when MLP nanoparticles are fixed at a concentration of 20 mg mL-1. CONCLUSION: The overall findings indicated that MLP nanoparticles have potential as food-grade materials for Pickering emulsions, marking a novel application of these nanoparticles in the food industry. © 2024 Society of Chemical Industry.

The isolation and characterisation of protein from nine edible insect species.

The increasing global population and consumer demand for protein pose a serious challenge to the provision of protein-rich diets. Insect farming has been suggested to have a lower environmental impact than conventional animal husbandry which makes insect consumption a more sustainable solution to meet the growing world population's protein requirements. However, there is a reluctancy in the adoption of insect protein especially in the Western diets as whole insect consumption is often met with disgust and resentment. To mitigate against the feeling of disgust and resentment, there have been suggestion to include insects as an ingredient in product development. However, for this to be successfully carried out, the techno-functional properties of insect protein need to be characterised. Therefore, the aim of this study was to isolate and characterise proteins from nine edible insect species. Protein was isolated from nine edible insect species and characterised in terms of the protein content and molecular weight distribution. As crickets are the most common insect food source, the functional characterisation (foaming and emulsification) of protein extracted from house cricket (HC) supernatant protein (SP) was investigated in comparison to commercial whey protein (WP) and pea protein isolate (PPI). The protein content of the buffalo worms and yellow meal worms was significantly (P = 0.000) higher than other insect species such as wild black ants, queen leaf cutter ants, and flying termites. The molecular weight distribution of the nine edible insect species varied from ~ 5 to 250 kDa. HC SP foaming capacity was fourfold and threefold higher than that of WP and PPI respectively. The emulsification potential of HC SP was 1.5 × higher than PPI. The HC protein extract shows promising potential for use in the food industry and represents a potential vehicle for the introduction of insect protein into the diet of societies that are not accustomed to eating insects.

Dispersion and mixing dynamics of complex oil-in-water emulsions in Taylor-Couette flows.

The seminal study by G. I. Taylor (1923) has inspired generations of work in exploring and characterizing Taylor-Couette (TC) flow instabilities and laid the foundation for research of complex fluid systems requiring a controlled hydrodynamic environment. Here, TC flow with radial fluid injection is used to study the mixing dynamics of complex oil-in-water emulsions. Concentrated emulsion simulating oily bilgewater is radially injected into the annulus between rotating inner and outer cylinders, and the emulsion is allowed to disperse through the flow field. The resultant mixing dynamics are investigated, and effective intermixing coefficients are calculated through measured changes in the intensity of light reflected by the emulsion droplets in fresh and salty water. The impacts of the flow field and mixing conditions on the emulsion stability are tracked via changes in droplet size distribution (DSD), and the use of emulsified droplets as tracer particles is discussed in terms of changes in the dispersive Péclet, Capillary and Weber numbers. For oily wastewater systems, the formation of larger droplets is known to yield better separation during a water treatment process, and the final DSD observed here is found to be tunable based on salt concentration, observation time and mixing flow state in the TC cell. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (Part 2)'.

The Synergistic Effects between Sulfobetaine and Hydrophobically Modified Polyacrylamide on Properties Related to Enhanced Oil Recovery.

In order to explore the mechanism responsible for the interactions in the surfactant-polymer composite flooding and broaden the application range of the binary system in heterogeneous oil reservoirs, in this paper, the influences of different surfactants on the viscosity of two polymers with similar molecular weights, partially hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM), were studied at different reservoir environments. In addition, the relationship between the surfactant-polymer synergistic effects and oil displacement efficiency was also investigated. The experimental results show that for HPAM, surfactants mainly act as an electrolyte to reduce its viscosity. For HMPAM, SDBS and TX-100 will form aggregates with the hydrophobic blocks of polymer molecules, reducing the bulk viscosity. However, zwitterionic surfactant aralkyl substituted alkyl sulfobetaine BSB molecules can build "bridges" between different polymer molecules through hydrogen bonding and electrostatic interaction. After forming aggregates with HMPAM molecules, the viscosity will increase. The presence of two polymers all weakened the surfactant oil-water interfacial membrane strength to a certain extent, but had little effect on the interfacial tension. The synergistic effect of the "bridge" between HMPAM and BSB under macroscopic conditions also occurs in the microscopic pores of the core, which has a beneficial effect on improving oil recovery.

A Review of the Utilization of Canola Protein as an Emulsifier in the Development of Food Emulsions.

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.

Amino acid regulated citrus pectin-based emulsion stability mediated by pH.

BACKGROUND: Citrus residuals are rich in nutrients like pectin, essential oil, and amino acids, which are wasted in the food industry. Moreover, citrus components often coexist with amino acids during emulsion preparation and application. RESULTS: Adding glutamic or arginine after emulsification resulted in a stable emulsion compared with adding them before emulsification. Adding glycine before or after emulsification had no effect on the emulsion stability. Emulsion stability was improved by adding glutamic acid at pH 6. Ionic interaction and hydrogen bonding were the main forms of bonding. The rhamnogalacturonan II domain was the potential binding site for the amino acids. CONCLUSIONS: The emulsions prepared by adding acidic amino acids or basic amino acids after emulsification were stable relative to those in which the amino acids were added before emulsification. However, the order in which neutral amino acids were added did not affect the emulsion stability after storage for 7 days. With an increase in the pH level, droplet size increased and emulsion stability decreased. All the results could be attributed to changes in the structure and properties of citrus pectin, as well as the interaction between citrus pectin and amino acids. This study may expand the application of citrus-derived emulsions in the food industry. © 2023 Society of Chemical Industry.

Blue agave inulin-soluble dietary fiber: effect on technological quality properties of pangasius mince emulsion-type sausage.

BACKGROUND: The aim of the work was to investigate the influence of supplementing pangasius mince-based emulsion sausages with blue agave-derived inulin at 1% (T1), 2% (T2), 3% (T3), 4% (T4), and 5% (T5) on its technological quality attributes and acceptability. RESULTS: The cooking yield of T-2, T-3, and T-4 sausages (96-97%) exhibited no significant difference (P > 0.05), which was higher than the other lots. The T-2 batter exhibited a significant difference with all other treatments, showing the lowest total expressible fluid (12.20%) value, indicating the highest emulsion stability of the batter. There was a significant effect on the diameter reduction of the cooked sausages as the level of inulin increased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the proteolysis of raw mince without inulin and new bands in cooked sausage samples were observed. Increasing inulin content increased the hardness of the sausages from 2510.81 ± 114.31 g to 3415.54 ± 75.88. The differential scanning calorimetry melting temperatures of peak 2 of the T-1, T-2, T-3, and T-4 increased as the inulin content increased from 1 to 4%. The scanning electron microscope images exhibited a smooth appearance on the surface as the inulin level increased. CONCLUSION: The sausages incorporated with the 2% and 3% blue agave plant-derived inulin (T-2 and T-3) showed better sensory overall acceptability scores than the control. The results suggested that the blue agave plant-derived inulin could be efficiently utilized at the 2% and 3% levels to enhance the quality of emulsion-type pangasius sausage. © 2023 Society of Chemical Industry.

Food protein glycation: A review focusing on stability and in vitro digestive characteristics of oil/water emulsions.

Recently, increasing studies have shown that the functional properties of proteins, including emulsifying properties, antioxidant properties, solubility, and thermal stability, can be improved through glycation reaction under controlled reaction conditions. The use of glycated proteins to stabilize hydrophobic active substances and to explore the gastrointestinal fate of the stabilized hydrophobic substances has also become the hot spot. Therefore, in this review, the effects of glycation on the structure and function of food proteins and the physical stability and oxidative stability of protein-stabilized oil/water emulsions were comprehensively summarized and discussed. Also, this review sheds lights on the in vitro digestion characteristics and edible safety of emulsion stabilized by glycated protein. It can further serve as a research basis for understanding the role of structural features in the emulsification and stabilization of glycated proteins, as well as their utilization as emulsifiers in the food industry.

Effects of monoacylglycerols with different saturation degrees on physical and whipping properties of milk fat-based whipping creams.

Milk fat-based whipping cream is primarily comprised of cream and whole milk. It has melt-in-the-mouth texture and unique milk flavor. However, milk fat-based whipping cream suffers from poor emulsion stability and foam firmness. The effects of monoacylglycerols (MAGs) with different saturation degrees (M1: 98% saturation, M2: 70% saturation and M3: 30% saturation) on emulsion properties (average particle size, viscosity, and emulsion stability) and whipping properties (overrun, firmness, shape retention ability, and foam stability) of milk fat-based whipping creams were investigated in this study. MAGs significantly decreased particle sizes (from 2.84 to 1.16 µm) and enhanced viscosity (from 350 to 490 cP) of the milk fat-based emulsions (emulsion without MAGs: M0, 5.01 µm, 298 cP) (P < 0.05). MAGs increased the stability of the milk fat-based emulsions with lesser phase separation during centrifugation tests and lower changes in particle sizes and viscosities during temperature cycling tests. Emulsion M1 with highest degree of saturation is less likely to destabilize and phase inverse. The decrease sharply in conductivity can be attributed to the entrapment of large amounts of air. Following that, the conductivity of M1 with low variation indicating high whipping resistance and less likely to coalescence and phase separation. Adding MAGs can significantly enhance overrun (M1: 205.3%, M2: 198.5%, M3: 141.4%) as compared to the control sample (M0: 97.9%) (P < 0.05). In emulsions containing MAGs with high degree of saturation (M1 and M2), firmness (M1: 95 g, M2: 109 g) and shape retention ability of the whipped creams were reduced as compared to control emulsion without MAG (M0: 173 g), but the foam stability (M1: 89%, M2: 91%) was enhanced (M0: 81%); M3 (firmness: 507 g; foam stability: 66%) has the contrasted effects. Whipping cream M2 demonstrated the best whipping properties with high overrun (198.46%), good firmness (109 g), shape retention ability and foam stability (91%). Good quality whipping creams can be obtained by selecting suitable MAGs.

Selection of green carrier solvent for the effective creation of bio-inspired liquid formulation and anti-fungal potency evaluation.

Existing pesticide formulation solvents generate volatile organic compounds (VOCs), are combustible, and are classed as hazardous air pollutants (HAPs), meaning they are detrimental to users and phytotoxic to crops. Green solvents are required in formulations due to regulations, health, and environmental concerns. In emulsifiable concentration (EC) formulations, the "green chemistry" movement has led to the use of less harmful solvents. After a detailed and comparative fungal growth inhibition assessment, the least harmful carrier solvent among four regularly used organic solvents [dimethyl sulfoxide (DMSO), dimethylformamide (DMF), aromatic hydrocarbon (C9), and methyl oleate] was chosen in this study. We employed methyl oleate (cis-9-Octadecenoic acid methyl ester) as a bio-based green reserver (60%) to create effective bioinspired EC formulations (30%) of Pongamia pinnata L extract utilising emulsifier blends (10 percent) based on the known toxicity order (DMF > DMSO > C9 > methyl oleate). EC1 outperformed the other thirteen formulations (EC1-EC13) in terms of emulsion stability, cold test, accelerated storage stability, flash point, and other metrics, proving its suitability for commercial production. Using four therapeutically appropriate concentrations of agricultural usage, in-vitro fungicidal effects against Alternaria solani and Phytophthora spp. were examined.A. solani (EC50 = 0.08 percent) showed the greatest growth suppression (87.4 percent) at the maximum dosage (1 percent), followed by Phytophthora sp. (71.1 percent) (EC50 = 0.49 percent). The study proved its utility in the production of environmentally acceptable green solvent-based herbal formulations as a long-term crop protection alternative to harmful chemical pesticides.

The interaction of milk sphingomyelin and proteins on stability and microstructure of dairy emulsions.

The interaction between dairy proteins [micellar casein (MC) vs. whey protein isolate (WPI)] and phospholipids [PL; soy phosphatidylcholine (PC) vs. milk sphingomyelin (SM)] in an oil-in-water emulsion system was investigated. Sole PC-stabilized emulsion (1%, wt/vol) showed a significantly larger mean particle diameter (6.5 µm) than SM-stabilized emulsions (3.8 µm). The mean particle diameters of emulsions prepared by the combination of protein (1%, wt/vol) and PL (1%, wt/vol) did not significantly differ from the emulsions prepared with a single emulsifier (MC, WPI, and SM). Emulsion instability differed significantly among samples by a centrifugation-mediated accelerated stability test. Emulsion instability increased in the order of MC+SM < MC+PC, WPI+SM < WPI+PC < MC < SM < WPI < PC. Protein surface load determined by aqueous phase depletion was significantly decreased only in WPI+PC emulsion, whereas no significant difference was found between the MC+SM and WPI+SM emulsions. Topographic and phase images of emulsion surface by atomic force microscopy showed surface layers prepared by protein+PL combinations were composites with different mechanical properties, and PL formed a more compact domain than proteins. A smoother phase image was observed in MC+PL combinations than in WPI+PL counterparts. Based on the microstructure analysis using confocal laser scanning microscopy, combination and MC+SM formed a uniform and thick surface coating of fat droplets. More PC aggregates were observed in the emulsions containing PC (sole PC, MC+PC, and WPI+PC) compared with their SM counterparts. Based on these results, the appropriate selection of the PL matrix is important to modulate the emulsion stability of dairy emulsion products.

The Effect of Precipitation pH on Protein Recovery Yield and Emulsifying Properties in the Extraction of Protein from Cold-Pressed Rapeseed Press Cake.

Rapeseed is the second most cultivated oilseed after soybean and is mainly used to produce vegetable oil. The by-product rapeseed press cake is rich in high-quality proteins, thus having the possibility of becoming a new plant protein food source. This study aimed to investigate how the precipitation pH affects the protein yield, protein content, and emulsifying properties when industrially cold-pressed rapeseed press cake is used as the starting material. Proteins were extracted under alkaline conditions (pH 10.5) with an extraction coefficient of 52 ± 2% followed by precipitation at various pH (3.0-6.5). The most preferred condition in terms of process efficiency was pH 4.0, which is reflected in the zeta potential results, where the proteins' net charge was 0 at pH 4.2. pH 4.0 also exhibited the highest protein recovery yield (33 ± 0%) and the highest protein concentration (64 ± 1%, dry basis). Proteins precipitated at pH 6.0-6.5 stabilized emulsions with the smallest initial droplet size, although emulsions stabilized by rapeseed protein precipitated at pH 5.0-6.0 showed the highest emulsion stability at 37 °C for 21 days, with a limited layer of free oil. Overall, emulsion stabilized by protein precipitated at pH 5.0 was the most stable formulation, with no layer of free oil after 21 days of incubation.