Lentil and chickpea protein-stabilized emulsions: optimization of emulsion formulation

Encapsulation of Cumin (Cuminum cyminum L.) Seed Essential Oil in the Chickpea Protein-Maltodextrin Matrix

Isoelectrically precipitated chickpea protein isolate (CPI) and its combination with maltodextrin (MD) were investigated for the ability to form and stabilize cumin seed oil emulsions. Solubility, net surface charge, emulsion activity/stability indices, and creaming stability of CPI at a pH of 3.0-9.0 were evaluated. Optimum conditions for minimum cream separation were identified as: 0.19% CPI and 6.83% oil concentrations. Cumin (Cuminum cyminum L.) seed essential oil was microencapsulated within the CPI-MD matrix via spray drying. Effects of CPI-MD matrix formulation on the physicochemical characteristics and volatile composition of the microencapsules were investigated. CPI-MD matrices had positive effects on microcapsule properties such as relatively lower surface oil, higher encapsulation efficiency (EE), and oil retention. Approximately 86.6-96.4% oil retention and 90.9-98.4% EE were achieved. Optimum conditions for maximized oil retention (92.9%) and EE (98.6%) were identified as: 2.1% CPI, 14.8% essential oil, and 35% MD. GC-MS analysis of microcapsules was carried out to determine the changes in volatile composition during spray drying. Cymene, α-pinene, β-pinene, sabinene, terpinene, terpineol, phellandrene, and cumin aldehyde were determined as the major components. Optimized design showed the highest EE and minimal changes in the volatile composition of cumin seed essential oil.

Limnophila aromatica Crude Extracts as Natural Emulsifiers for Formation and Stabilizing of Oil-in-Water (O/W) Emulsions

This study mainly focused on the emulsifying performance of Limnophila aromatica crude extracts obtained by using different ethanolic aqueous solutions (0, 25, 50, 75, and 99.5% (v/v)). All Limnophila aromatica extracts (LAEs) were able to produce emulsions with a volume mean droplet diameter (d4,3) ranging from 273 to 747 nm, except for LAE-99.5 (3269 nm). Only the emulsion prepared by LAE-75 was stable during seven days of storage, without significantly changing droplet size (479–495 nm). The result showed that all LAEs could reduce interfacial tension varied within 12.5 and 16.1 mN/m at the soybean oil/extracts (1% w/w) interface. Compared to other extracts, LAE-75 did not contain the highest protein, saponin, and phenol content (4.36%, 20.14%, and 11.68%, respectively), but it had the lowest ash content (14.74%). These results indicated that the emulsifying performance of LAEs did not rely only on interfacial tension and/or surface-active compounds. The residual demulsifiers, such as inorganic substances, were also significantly involved in the emulsions’ destabilization. Finally, the emulsion consisting of 0.5% (w/w) LAE-75 and 5% (w/w) soybean oil showed considerable stability during storage up to 30 days at different temperatures (5 or 25 °C). Therefore, Limnophila aromatica extract has a potential application as a new source of natural emulsifier.

Improved Oxidation Stability of Camellia Oil-in-Water Emulsions Stabilized by the Mixed Monolayer of Soy Protein Isolate/Bamboo Shoot Protein Complexes

The complex of soy protein isolate (SPI)/bamboo shoot protein concentrate (BPC) was developed to stabilize camellia oil-in-water (O/W) emulsions. The surface hydrophobicity of the BPC/SPI complex driven by hydrogen bonds and electrostatic attractions was improved. With the increasing ratio of BPC in the complex, a tighter network layer structure of the complex was formed due to the rearrangement of proteins, and the emulsions showed a progressive enhancement in the gel-like structures. At the SPI/BPC ratio of 2:1, the emulsions had smaller droplet size and lower creaming index of 230 nm and 30%, and the emulsifying activity and stability indices of the emulsions were 803.72 min and 11.85 g/m², respectively, indicating a better emulsifying activity and stability of emulsions. Meanwhile, the emulsions stabilized by the complex at the ratio of 2:1 showed better storage and antioxidant stability. These findings are expected to develop the application of bamboo shoots in emulsion-based food products such as mayonnaise, salad dressings, and sauces.

Biorefinery of Green Biomass─How to Extract and Evaluate High Quality Leaf Protein for Food?

There is a growing need for protein for both feed and food in order to meet future demands. It is imperative to explore and utilize novel protein sources such as protein from leafy plant material, which contains high amounts of the enzyme ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCo). Leafy crops such as grasses and legumes can in humid climate produce high protein yields in a sustainable way when compared with many traditional seed protein crops. Despite this, very little RuBisCo is utilized for foods because proteins in the leaf material has a low accessibility to monogastrics. In order to utilize the leaf protein for food purposes, the protein needs to be extracted from the fiber rich leaf matrix. This conversion of green biomass to valuable products has been labeled green biorefinery. The green biorefinery may be tailored to produce different products, but in this Review, the focus is on production of food-grade protein. The existing knowledge on the extraction, purification, and concentration of protein from green biomass is reviewed. Additionally, the quality and potential application of the leaf protein in food products and side streams from the green biorefinery will be discussed along with possible uses of side streams from the protein production.

Two Statistical Tools for Assessing Functionality and Protein Characteristics of Different Fava Bean (Vicia faba L.) Ingredients

Fava bean (Vicia faba L.) is a promising source of proteins that can be potentially used as nutritional and/or functional agents for industrial food applications. Fava ingredients are industrially produced, modified, and utilized for food applications. Their processing conditions influence physico-chemical protein properties that further impact ingredient functionality. To design a functionally suitable ingredient, an understanding of the interrelationships between different properties is essential. Hence, this work aimed to assess two statistical analytical tools, Pearson’s correlation and Principal Component Analysis (PCA), for investigating the role of the process conditions of fava ingredients on their functional and protein properties. Fava concentrates were processed by pH (2, 4, 6.4 and 11), temperature (55, 75 and 95 °C) and treatment duration (30 and 360 min) into different modified ingredients. These were utilized under two application conditions (pH 4 and 7), and their foam and emulsion properties as well as their ingredient characteristics (charge, solubility, and intrinsic fluorescence) were measured. The results show that foam and emulsion properties are not correlated to each other. They are associated with different protein and non-protein attributes as fava concentrate is a multi-component matrix. Importantly, it is found that the results from the two statistical tools are not fully comparable but do complement each other. This highlights that both statistical analytical tools are equally important for a comprehensive understanding of the impact of process conditions on different properties and the interrelationships between them. Therefore, it is recommended to use Pearson’s correlation and principal component analysis in future investigations of new plant-based proteins.

Alternative Protein Sources as Technofunctional Food Ingredients

Proteins obtained from alternative sources such as plants, microorganisms, and insects have attracted considerable interest in the formulation of new food products that have a lower environmental footprint and offer means to feed a growing world population. In contrast to many established proteins, and protein fractions for which a substantial amount of knowledge has accumulated over the years, much less information is available on these emerging proteins. This article reviews the current state of knowledge on alternative proteins and their sources, highlighting gaps that currently pose obstacles to their more widespread application in the food industry. The compositional, structural, and functional properties of alternative proteins from various sources, including plants, algae, fungi, and insects, are critically reviewed. In particular, we focus on the factors associated with the creation of protein-rich functional ingredients from alternative sources. The various protein fractions in these sources are described as well as their behavior under different environmental conditions (e.g., pH, ionic strength, and temperature). The extraction approaches available to produce functional protein ingredients from these alternative sources are introduced as well as challenges associated with designing large-scale commercial processes. The key technofunctional properties of alternative proteins, such as solubility, interfacial activity, emulsification, foaming, and gelation properties, are introduced. In particular, we focus on the formation of isotropic and anisotropic structures suitablefor creating meat and dairy product analogs using various structuring techniques. Finally, selected studies on consumer acceptance and sustainability of alternative protein products are considered.

Encapsulation of black pepper seed oil using maltodextrin and pea protein

The goal of this research was to determine the physicochemical and emulsifying properties of pea protein, gum arabic, and maltodextrin and to investigate their potential for stabilizing black pepper seed oil emulsions and acting as carrier materials for spray dried microcapsules. The moisture content and water activity of pea protein and maltodextrin (∼5.5 g/100 g and ∼0.22) were found to be significantly lower than that of gum arabic (11.5 g/100 g and 0.46) whereas the glass transition temperatures of pea protein and maltodextrin (∼99.4 ℃) was significantly higher than that of gum arabic (72 ℃). Pea protein showed the highest viscosity (53.8 mPa s), the lowest surface tension (42.5 mN/m), and interfacial tension (10.5 mN/m) among the biopolymer materials studied. A mixture design was employed to investigate the effect of biopolymer formulation on droplet size and creaming stability of black pepper seed oil emulsions. Stable emulsions with relatively smaller droplet size were spray dried to produce microcapsules. Spray dried black pepper seed oil microcapsules produced with 1% pea protein and 39% maltodextrin had low surface oil (∼0.8%) and high encapsulation efficiency (95%). The results of this study suggest that pea protein in combination with maltodextrin can be used as carrier materials in encapsulation of black pepper seed oil.

Sugar Beet Extract (Beta vulgaris L.) as a New Natural Emulsifier: Emulsion Formation

The interfacial and emulsion-forming properties of sugar beet extract (Beta vulgaris L.) were examined and compared to a Quillaja extract that is widely used within the food industry. We investigated the influence of extract concentration on surface activity at oil-water and air-water interfaces and on the formation of oil-in-water emulsions (10% w/w, pH 7). Sugar beet extract reduced the interfacial tension up to 38% at the oil-water interface, and the surface tension up to 33% at the air-water surface. The generated emulsions were negatively charged (ζ ≈ -46 mV) and had the smallest particle sizes (d₄₃) of ∼1.3 μm at a low emulsifier-to-oil ratio of 0.75:10. Applying lower or higher extract concentrations increased the mean particle sizes. The smallest emulsions were formed at an optimum homogenization pressure of 69 MPa. Higher homogenization pressures led to increased particle sizes. Overall, sugar beet extract showed high surface activity. Furthermore, the formation of small emulsion droplets was successful; however, the droplets were bigger compared to those from the Quillaja extract. These results indicate sugar beet as an effective natural emulsifier that may be utilized for a variety of food and beverage applications.

Recent Advances in the Utilization of Natural Emulsifiers to Form and Stabilize Emulsions

Consumer concern about human and environmental health is encouraging food manufacturers to use more natural and sustainable food ingredients. In particular, there is interest in replacing synthetic ingredients with natural ones, and in replacing animal-based ingredients with plant-based ones. This article provides a review of the various types of natural emulsifiers with potential application in the food industry, including phospholipids, biosurfactants, proteins, polysaccharides, and natural colloidal particles. Increased utilization of natural emulsifiers in food products may lead to a healthier and more sustainable food supply. However, more research is needed to identify, isolate, and characterize new sources of commercially viable natural emulsifiers suitable for food use.

Natural emulsifiers - Biosurfactants, phospholipids, biopolymers, and colloidal particles: Molecular and physicochemical basis of functional performance

There is increasing consumer pressure for commercial products that are more natural, sustainable, and environmentally friendly, including foods, cosmetics, detergents, and personal care products. Industry has responded by trying to identify natural alternatives to synthetic functional ingredients within these products. The focus of this review article is on the replacement of synthetic surfactants with natural emulsifiers, such as amphiphilic proteins, polysaccharides, biosurfactants, phospholipids, and bioparticles. In particular, the physicochemical basis of emulsion formation and stabilization by natural emulsifiers is discussed, and the benefits and limitations of different natural emulsifiers are compared. Surface-active polysaccharides typically have to be used at relatively high levels to produce small droplets, but the droplets formed are highly resistant to environmental changes. Conversely, surface-active proteins are typically utilized at low levels, but the droplets formed are highly sensitive to changes in pH, ionic strength, and temperature. Certain phospholipids are capable of producing small oil droplets during homogenization, but again the droplets formed are highly sensitive to changes in environmental conditions. Biosurfactants (saponins) can be utilized at low levels to form fine oil droplets that remain stable over a range of environmental conditions. Some nature-derived nanoparticles (e.g., cellulose, chitosan, and starch) are effective at stabilizing emulsions containing relatively large oil droplets. Future research is encouraged to identify, isolate, purify, and characterize new types of natural emulsifier, and to test their efficacy in food, cosmetic, detergent, personal care, and other products.

Polypeptide modification: an improved proglycinin design to stabilise oil-in-water emulsions

β-Conglycinin and glycinin are soybean major seed storage proteins. Previous studies have shown that adding the extension region of β-conglycinin α subunit improves the emulsifying properties of proglycinin and confers more favourable characteristics than fusing the extension region of β-conglycinin α' subunit or the hypervariable regions (A4IV) of glycinin A1aB1b subunit. To evaluate the polypeptide properties, we designed mutants of A1aB1b subunits fused with truncated versions of A4IV (A4IVcut), α (αcut) or α' (α'cut) extension regions lacking the C-terminus 25 or 31 residues (A4IVC25, αC25 or α'C31), and also A4IVcut and α'cut with αC25 residues added (A4IVcut-αC25 and α'cut-αC25). All the modified proteins displayed conformations similar to the wild type. With good solubilities, the emulsion properties of the modified proteins were much better at ionic strength μ = 0.08 than at μ = 0.5. The modified A1aB1bαcut and A1aB1bα'cut showed poorer emulsion properties than those of A1aB1bα and A1aB1bα'. Replacing the hydrophobic A4IVC25 region of A1aB1bA4IV with hydrophilic αC25 created A1aB1bA4IVcut-αC25, which had the best emulsion stability among these proglycinin mutants. We found that addition of αC25 improves the emulsifying properties of two C-terminally truncated proglycinin variants, thereby illustrating its potential general utility. Our investigation showed that in order to improve the emulsifying ability and emulsion stability of a globular protein, the introduced polypeptide should (i) be highly hydrophilic, (ii) consist of multiple hydrophobic-strong hydrophilic regions comprising at least two alpha helixes, (iii) harbour a terminal α-helix at the end of the C-terminus and (iv) have properties similar to those of αC25.

Encapsulation of flaxseed oil using a benchtop spray dryer for legume protein-maltodextrin microcapsule preparation

Flaxseed oil was microencapsulated employing a wall material matrix of either chickpea (CPI) or lentil protein isolate (LPI) and maltodextrin using a benchtop spray dryer. Effects of emulsion formulation (oil, protein and maltodextrin levels) and protein source (CPI vs LPI) on the physicochemical characteristics, oxidative stability, and release properties of the resulting capsules were investigated. Microcapsule formulations containing higher oil levels (20% oil, 20% protein, 60% maltodextrin) were found to have higher surface oil and lower encapsulation efficiencies. Overall, LPI-maltodextrin capsules gave higher flaxseed oil encapsulation efficiencies (∼88.0%) relative to CPI-maltodextrin matrices (∼86.3%). However, both designs were found to provide encapsulated flaxseed oil protection against oxidation over a 25 d room temperature storage study relative to free oil. Overall, ∼37.6% of encapsulated flaxseed oil was released after 2 h under simulated gastric fluid, followed by the release of an additional ∼46.6% over a 3 h period under simulated intestinal fluid conditions.

Microwave drying for safe storage and improved nutritional quality of green gram seed (Vigna radiata)

The present study describes the effect of the microwave-heating method on disinfestations and physico characteristics, viz., grain size, grain hardness, and nutritional quality, of the stored green gram seed. It has been observed that the use of the microwave-heating method not only prolongs the storage duration of the green gram seed but also enhances its nutritional quality. The effect of independent parameters, viz., microwave power level and time of exposure, on the moisture content, insect mortality, color, and antinutrient factor (phyic acid) was optimized using response surface methodology (RSM), with the optimized value for power of 808 W and time at 80 s. The optimally treated green gram seed has 8.9% moisture, 99.5% insect mortality, 2.22 Δa* (green color of seed), and 591.79 mg/100 g of antinutrient factor (phytic acid). The grain size (geometric mean diameter, D(m)) of the control (untreated) sample was 3.75 mm, and that of the microwave-treated sample using optimum conditions was 3.99 mm. The grain hardness of the control sample was 3.31 kg, and that of the microwave-treated sample using optimum conditions was 1.305 kg. In vitro protein digestibility (IVPD) of the control (untreated) sample was 83 ± 0.289%, and that of the microwave-treated sample using optimum conditions was 85 ± 0.296%. These values are significantly difference (p < 0.05). The mineral elements studied were Zn, Fe, Mg, Mn, Cu, K, Ca, and Na. The microwave treatment resulted in a non-significant (p < 0.05) effect for Mg, Mn, Cu, K, and Na but a significant (p < 0.05) effect for Zn, Ca, and Fe. The results indicate that the microwave heating not only increases the insect mortality but also reduces the moisture content and antinutritional factor (phytic acid), while the natural green color of the seed is not affected much. This study provides a novel and environmentally safe technique and increase in the nutritive quality.