Food protein functionality: A comprehensive approach

Preparation of Oxidized Starch/β-Lactoglobulin Complex Particles Using Microfluidic Chip for the Stabilization of Astaxanthin Emulsion

Here, we designed an oxidized starch/β-lactoglobulin (OS/β-lg) complex colloidal particle using a dual-channel microfluidic chip for the stabilization of astaxanthin emulsion. The effect of the mixing ratio, pH, and the degree of substitution (DS) of the oxidized starch on the formation of OS/β-lg complex particles was investigated in detail. The optimal complexation occurred at a pH of 3.6, a mixing ratio of 2:10, and a DS of 0.72%, giving an ideal colloidal particle with near-neutral wettability. With this optimum agent, the astaxanthin-loaded oil-in-water emulsions were successfully prepared. The obtained emulsions showed the typical non-Newton fluid behavior, and the rheological data met the Herschel-Bulkley model. The microscopic images confirmed the dense adsorption of the particle on the oil/water interface. In vitro release and stability studies demonstrated this compact layer contributed to the controlled-release and excellent stability of astaxanthin emulsions facing heat, ultraviolet, and oxidative intervention. This work suggests the potential of microfluidics for the production of food-grade solid emulsifiers.

Functional proteins through green refining of seafood side streams

Scarcity of nutritive protein is a major global problem, the severity of which is bound to increase with the rising population. The situation demands finding additional sources of proteins that can be both safe as well as acceptable to the consumer. Food waste, particularly from seafood is a plausible feedstock of proteins in this respect. Fishing operations result in appreciable amounts of bycatch having poor food value. In addition, commercial processing results in 50 to 60% of seafood as discards, which consist of shell, head, fileting frames, bones, viscera, fin, skin, roe, and others. Furthermore, voluminous amounts of protein-rich effluents are released during commercial seafood processing. While meat from the bycatch can be raw material for proteinous edible products, proteins from the process discards and effluents can be recovered through biorefining employing upcoming, environmental-friendly, low-cost green processes. Microbial or enzyme treatments release proteins bound to the seafood matrices. Physico-chemical processes such as ultrasound, pulse electric field, high hydrostatic pressure, green solvent extractions and others are available to recover proteins from the by-products. Cultivation of photosynthetic microalgae in nutrient media consisting of seafood side streams generates algal cell mass, a rich source of functional proteins. A zero-waste marine bio-refinery approach can help almost total recovery of proteins and other ingredients from the seafood side streams. The recovered proteins can have high nutritive value and valuable applications as nutraceuticals and food additives.

Maximizing Recovery of Paenibacillin, a Bacterially Produced Lantibiotic, Using Continuous Foam Separation from Bioreactors

Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient methods to recover these peptides from fermentor or bioreactor end products. Preliminary data showed that paenibacillin was preferentially partitioned in foam accumulated during growth of the producer, Paenibacillus polymyxa, in aerated liquid media. This research was initiated to improve the production and recovery of paenibacillin in bioreactors by maximizing partitioning of this antimicrobial agent in the collected foam. This was completed through harvesting foam continuously during paenibacillin production, using modified bioreactor, and optimizing bioreaction conditions through response surface methodology (RSM). During initial screening, the following factors were tested using 400 mL inoculated media in 2 L bioreactors: medium (tryptic soy broth, TSB, with or without added yeast extract), airflow (0 or 0.8 L/min; LPM), stir speed (300 or 500 revolution/min; RPM), incubation temperature (30 or 36 °C), and incubation time (16 or 24 h). Results showed that airflow, time, and stir speed had significant effects (p < 0.05) on paenibacillin recovery in the collected collapsed foam (foamate). These factors were varied together to follow the path of steepest assent to maximize paenibacillin concentration. Once the local maximum was found, RSM was completed with a central composite design to fine-tune the bioreaction parameters. The optimization experiments proved that the significant parameters and their optimal conditions for paenibacillin concentration in the foam were: incubation at 30 °C for 23 h with airflow of 0.95 LPM, and agitation speed of 450 RPM. These conditions increased paenibacillin concentration, predicted by RSM, from 16 µg/mL in bioreaction without foam collection to 743 µg/mL collected in foamate. The optimized conditions also almost doubled the yield of paenibacillin measured in the foam collected from a bioreaction run (12,674 µg/400 mL bioreaction) when compared to that obtained from a run without foam collection (6400 µg/400 mL bioreaction). Results of this study could improve the feasibility of commercial production and downstream processing of paenibacillin and similar novel antimicrobial peptides. Availability of such peptides will eventually help in protecting perishable products against pathogenic and spoilage bacteria.

Drying Microalgae Using an Industrial Solar Dryer: A Biomass Quality Assessment

Microalgae are considered a promising resource of proteins, lipids, carbohydrates, and other functional biomolecules for food and feed markets. Competitive drying solutions are required to meet future demands for high-quality algal biomass while ensuring proper preservation at reduced costs. Since often used drying methods, such as freeze or spray drying, are energy and time consuming, more sustainable processes remain to be developed. This study tested an indirect and hybrid solar dryer as an alternative to conventional freeze drying of industrially produced Tetraselmis chui and Nannochloropsis oceanica wet paste. The effects of the drying method on biomass quality parameters, including biochemical profiles, functional properties, and microbial safety, were assessed. No significant differences were found between the applied drying technologies for total proteins, carbohydrates, lipids, and fatty acid profiles. On the other hand, some pigments showed significant differences, displaying up to 44.5% higher contents in freeze-dried samples. Minor differences were also registered in the mineral profiles (<10%). Analyses of microbial safety and functional properties of the solar-dried biomass appear adequate for food and feed products. In conclusion, industrial solar drying is a sustainable technology with a high potential to preserve high-quality microalgal biomass for various markets at expected lower costs.

The Impact of Dehulling and Germination on the Physiochemical, Protein Solubility and Water and Oil Holding Capacities of Yellow Eye Bean (Phaseolus vulgaris L.) Protein Concentrates

Pulse varieties including Yellow Eye (YE) beans (Phaseolus vulgaris L.) are a rich source of protein (~26.5%) that can be utilized to create value-added protein concentrates. Pre-treatments including dehulling and germination have been shown to be effective at improving the nutritional and functional properties of extracted protein concentrates. However, the composition and functionality of these protein concentrates can vary depending on the pre-treatments and the method of extraction used (salt vs. alkaline). Furthermore, little is known about the impact of combining these different processing methods on the properties of YE bean protein concentrates. The objective of this study was to evaluate how germination and dehulling pre-treatments individually and when combined influence protein extraction efficiency, physiochemical properties (surface hydrophobicity and intrinsic fluorescence), and the functionality (solubility, oil and water holding capacities) of salt and alkaline extracted protein concentrates. Compared to the salt extracted concentrates, the alkaline protein concentrates exhibited higher protein recovery yields (16–23% vs. 43–56%) respectively. Conversely, the salt extracted protein concentrates exhibited superior functional properties as observed by improved water holding capacities and less variation in their solubilities at different pH values (4 to 10). When the pre-treatments were combined, the salt extracted concentrates exhibited improved extraction efficiencies and improved hydrophobicity and intrinsic fluorescence, whereas the opposite trend was observed in the alkaline protein concentrates. These observations were attributed to differences in the protein content and composition of the salt vs. alkaline protein concentrates. Overall, these findings suggest that dehulling and germination are potential processing methods that may be used to improve the physiochemical characteristics of salt extracted protein concentrates from yellow eye beans. Future research may investigate the potential application of these ingredients in different food formulations.

Thermo-mechanical processing of fibre-rich blackcurrant pomace to modify techno-functional properties

Exploring the use of seedless blackcurrant pomace, a fibre-rich by-product of juice pressing, in foods is favourable due to its nutritional profile but also for economic and sustainability aspects. Current applications are limited to products in which rapid fibre swelling, high water solubility or low sedimentation is not essential. In this study, functional properties of seedless blackcurrant pomace were modified by thermo-mechanical treatments using extrusion cooking or micronization in a planetary ball mill. A full factorial design showed that low pomace moisture (11 g/100 g) had the highest impact on swelling capacity (+ 20.6%) and water solubility index (+ 23.2%), whereas variation in extrusion temperature exhibited only minor effects. After milling for 4 h, the median particle size was reduced by 98% to 4 µm and the specific surface area increased from 0.1 to 2.5 m2/mL. Swelling capacity was highest after this time with 7.6 mL/g pomace and, although the amount of extractable sugars was reduced, water solubility increased to 7.6 g/100 g. In contrast to extruded samples, the red colour of the pomace was intensified after milling. Both treatments appear as promising to extend the applicability of fruit by-products in foods, as micronized pomace may counteract sedimentation in liquids, whereas increased swelling capacity after extrusion may have stabilizing effects on yoghurt-like systems.

Enzymatic Hydrolysis of Pulse Proteins as a Tool to Improve Techno-Functional Properties

Pulse proteins are being increasingly investigated as nutritious and functional ingredients which could provide alternatives to animal proteins; however, pulse protein ingredients do not always meet the functionality requirements necessary for various applications. Consequently, enzymatic hydrolysis can be employed as a means of improving functional properties such as solubility, emulsifying, foaming, and gelling properties. This review aims to examine the current literature regarding modification of these properties with enzymatic hydrolysis. The effects of enzymatic hydrolysis on the functionality of pulse proteins generally varies considerably based on the enzyme, substrate, processing steps such as heat treatment, degree of hydrolysis, and pH. Differences in protease specificity as well as protein structure allow for a wide variety of peptide mixtures to be generated, with varying hydrophobic and electrostatic properties. Typically, the most significant improvements are seen when the original protein ingredient has poor initial functionality. Solubility is usually improved in the mildly acidic range, which may also correspond with improved foaming and emulsifying properties. More work should be carried out on the potential of enzymatic hydrolysis to modify gelation properties of pulse proteins, as the literature is currently lacking. Overall, careful selection of proteases and control of hydrolysis will be necessary to maximize the potential of enzymatic hydrolysis as a tool to improve pulse protein functionality and broaden the range of potential applications.

Pea protein composition, functionality, modification, and food applications: A review

The demand for proteins continues to increase due to their nutritional benefits, the growing world population, and rising protein deficiency. Plant-based proteins represent a sustainable source to supplement costly animal proteins. Pea (Pisum sativum L.) is one of the most produced plant legume crops in the world and contributes to 26% of the total pulse production. The average protein content of pea is about 20%-25%. The commercial utilization of pea proteins is limited, partially due to its less desirable functionalities and beany off-flavor. Protein modification may change these properties and broaden the application of pea proteins in the food industry. Functional properties such as protein solubility, water and oil holding capacity, emulsifying/foaming capacity and stability, and gelation can be altered and improved by enzymatic, chemical, and physical modifications. These modifications work by affecting protein chemical structures, hydrophobicity/hydrophilicity balance, and interactions with other food constituents. Modifiers, reaction conditions, and degree of modifications are critical variables for protein modifications and can be controlled to achieve desirable functional attributes that may meet applications in meat analogs, baking products, dressings, beverages, dairy mimics, encapsulation, and emulsions. Understanding pea protein characteristics will allow us to design better functional ingredients for food applications.

Evaluation of nutritional composition and technological functionality of whole American Bullfrog (Lithobates catesbeianus), its skin, and its legs as potential food ingredients

Frog farming systems do not take advantage of their byproducts, which represents health risks and environmental pollution. The present study aimed to evaluate the proximate composition, amino acid, and fatty acid profile of American Bullfrog byproducts (whole frogs (WF), legs (LF), and skin (SF)) and their technological functionality. Results showed that WF, LF, and SF protein content was 47.6, 88.4, and 91.1% dry base (d.b.), correspondingly. Fat content resulted in 34.6, 3.2, and 4.2% (d.b.), respectively. Moreover, byproducts contain all the essential amino acids (23.8-46.6%), and the unsaturated fatty acids predominated the saturated fats. Samples showed water and oil absorption capacities of 1.8-2.6% and 1.8-4.0%, respectively, while oil and water emulsion capacities were 76.7-98.3% and 36.1-85.6%, correspondingly. Additionally, SF presented a gelling capacity in a 5% concentration. These results showed that frogs' byproducts have adequate nutritional and functional capacities, compared to other vegetable and animal flours used in the industry.

Enzymatic synthesis, characterization and properties of the protein-polysaccharide conjugate: A review

Poor solubility of proteins negatively affects their functional properties and greatly limits their application. Enzymatic cross-linking with polysaccharides can improve solubility and functional properties of proteins. The enzymes used include transglutaminase, laccase and peroxidase. Therefore, this work introduces the cross-linking mechanisms of these enzymes and the characterization techniques, the improved properties and the potential applications of the enzymatically-synthesized protein-polysaccharide conjugate. Transglutaminase catalyzes the formation of a new peptide bond and thus works on amino-containing polysaccharides to conjugate with proteins. However, laccase and peroxidase catalyze oxidation of various compounds with phenol and aniline structures. Therefore, these two enzymes can catalyze the conjugate reaction between proteins and feruloylated polysaccharides which are widely distributed in cereal bran. Compared with the unmodified protein, the enzymatically-synthesized protein-polysaccharide conjugate usually has higher solubility and better functional properties. Thus, it is inferred that enzymatic conjugation with polysaccharide molecules can extend the application of proteins.

Sources, chemical synthesis, functional improvement and applications of food-derived protein/peptide-saccharide covalent conjugates: a review

Proteins/peptides and saccharides are two kinds of bioactive substances in nature. Recently, increasing attention has been paid in understanding and utilizing covalent interactions between proteins/peptides and saccharides. The products obtained through covalent conjugation of proteins/peptides to saccharides are shown to have enhanced functional attributes, such as better gelling property, thermostability, and water-holding capacity. Additionally, food-derived protein/peptide-saccharide covalent conjugates (PSCCs) also have biological activities, such as antibacterial, antidiabetic, anti-osteoporosis, anti-inflammatory, anti-cancer, immune regulatory, and other activities that are widely used in the functional food industry. Moreover, PSCCs can be used as packaging or delivery materials to improve the bioavailability of bioactive substances, which expands the development of food-derived protein and saccharide resources. Thus, this review was aimed to first summarize the current status of sources, classification structures of natural PSCCs. Second, the methods of chemical synthesis, reaction conditions, characterization and reagent formulations that improve the desired functional characteristics of food-derived PSCCs were introduced. Third, functional properties such as emulsion, edible films/coatings, and delivery of active substance, bio-activities such as antioxidant, anti-osteoporosis, antidiabetic, antimicrobial of food-derived PSCCs were extensively discussed.

Plant-Based Proteins: The Good, Bad, and Ugly

Our global population is growing at a pace to exceed 10 billion people by the year 2050. This growth will place pressure on the agricultural production of food to feed the hungry masses. One category that will be strained is protein. Per capita protein consumption is rising in virtually every country for both nutritional reasons and consumption enjoyment. The United Nations estimates protein demand will double by 2050, and this will result in a critical overall protein shortage if drastic changes are not made in the years preceding these changes. Therefore, the world is in the midst of identifying technological breakthroughs to make protein more readily available and sustainable for future generations. One protein sourcing category that has grown in the past decade is plant-based proteins, which seem to fit criteria established by discerning consumers, including healthy, sustainable, ethical, and relatively inexpensive. Although demand for plant-based protein continues to increase, these proteins are challenging to utilize in novel food formulations.

Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Comparative study of two types of pre-extraction treatment (drying or non-drying) on physicochemical, structural and functional properties of extracted insect proteins from Tenebrio molitor larvae

Microwave drying (MD) or freeze drying (FD) was commonly used as a drying treatment prior to the extraction of edible insect proteins. However, some quality defects (e.g., lipid oxidation or protein denaturation) were probably occurred via the drying step. To this end, the effect of drying or non-drying treatments (ND) after slaughtering by liquid nitrogen freezing on the physicochemical characteristics, structural and functional properties of Tenebrio molitor larvae protein (TMP) was investigated. The results indicate that TMP extracted from the ND group showed higher essential/total amino acid content, total/free sulfhydryl content, surface hydrophobicity, solubility, water/oil holding capacities, and emulsifying/foaming properties than those extracted from the MD or FD groups (P < 0.05). Moreover, the ND group had minimal impact on the structural changes of TMP which was associated with protein denaturation. Therefore, it can be concluded that a non-drying strategy prior to TMP extraction can improve functional properties and retard protein denaturation, while also conserving energy.

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Tenebrio molitor larvae was firstly slaughtered by liquid nitrogen freezing.

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Frozen larvae were subjected to either drying or non-drying treatment.

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Tenebrio molitor larvae protein (TMP) was extracted from dried or non-dried group.

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TMP extracted from the non-dried group had optimum functional properties.

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TMP extracted from the non-dried group had least degree of protein denaturation.

The Influence of Biomolecule Composition on Colloidal Beer Structure

Recent studies have revealed an interest in the composition of beer biomolecules as a colloidal system and their influence on the formation of beer taste. The purpose of this research was to establish biochemical interactions between the biomolecules of plant-based raw materials of beer in order to understand the overall structure of beer as a complex system of bound biomolecules. Generally accepted methods of analytical research in the field of brewing, biochemistry and proteomics were used to solve the research objectives. The studies allowed us to establish the relationship between the grain and plant-based raw materials used, as well as the processing technologies and biomolecular profiles of beer. The qualitative profile of the distribution of protein compounds as a framework for the formation of a colloidal system and the role of carbohydrate dextrins and phenol compounds are given. This article provides information about the presence of biogenic compounds in the structure of beer that positively affect the functioning of the body. A critical assessment of the influence of some parameters on the completeness of beer taste by biomolecules is given. Conclusion: the conducted analytical studies allowed us to confirm the hypothesis about the nitrogen structure of beer and the relationship of other biomolecules with protein substances, and to identify the main factors affecting the distribution of biomolecules by fractions.

Structure and in vitro bioactive properties of O/W emulsions generated with fava bean protein hydrolysates

The use of plant-derived proteins in the generation of food products is gaining popularity as an alternative to proteins of animal origin. This study described the emulsifying and bioactive properties of fava bean protein hydrolysates (FBH) generated at low and high degree of hydrolysis (DH), i.e., FBH₈ (low DH: 8.4 ± 0.3) and FBH₂₁₀ (high DH: 15.6 ± 0.7) when adjusted to three different pHs (3.0, 5.0 and 8.0). Overall, FBH₈, had more favourable emulsifying properties compared to the FBH_210. The emulsion generated with FBH₈ at pH 8.0 also had the highest antioxidant activity when measured by the oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays with values of 1108.6 ± 3.8 and 1159.9 ± 20.5 μmol Trolox Eq·g^-1 emulsion, respectively. The antioxidant activity of the emulsions, in most cases, remained unchanged following in vitro simulated gastrointestinal digestion. Both the FBH₈ and FBH₂₁₀ emulsions following in vitro simulated gastrointestinal digestion were able to inhibit the activities of dipeptidyl peptidase-IV (DPP-IV) and angiotensin converting enzyme (ACE) with ∼45% and 65% inhibition, respectively. These results indicated that hydrolysates from fava bean may find use for the generation of bioactive emulsions.

Mechanisms behind protein-protein interactions in a β-lg-legumin co-precipitate

Interactions between pea protein and whey protein isolates in co-precipitates and blends consist of a combination of disulphide bonds, hydrophobic and electrostatic interactions. The present study aims to clarify if the two proteins with free thiols, β-lactoglobulin (β-lg) and legumin, played a significant role for these interactions. This study used different reagents to modify the conditions of interactions: N-ethylmaleimide (NEM) was used to block reactive thiols, while NaCl and SDS were used to prevent electrostatic or hydrophobic interactions, respectively. The effects of treatments were studied on protein solubility, structure and stability. SDS had no effect, while NEM and NaCl both had great effect, especially in combination. The results showed that interactions of β-lg and legumin in both co-precipitates and blends are a synergism of electrostatic interactions and disulphide bonds. Thus, β-lg and legumin are the main proteins responsible for previously observed interactions in protein isolates of whey and pea.

Breeding Canola (Brassica napus L.) for Protein in Feed and Food

Interest in canola (Brassica napus L.). In response to this interest, scientists have been tasked with altering and optimizing the protein production chain to ensure canola proteins are safe for consumption and economical to produce. Specifically, the role of plant breeders in developing suitable varieties with the necessary protein profiles is crucial to this interdisciplinary endeavour. In this article, we aim to provide an overarching review of the canola protein chain from the perspective of a plant breeder, spanning from the genetic regulation of seed storage proteins in the crop to advancements of novel breeding technologies and their application in improving protein quality in canola. A review on the current uses of canola meal in animal husbandry is presented to underscore potential limitations for the consumption of canola meal in mammals. General discussions on the allergenic potential of canola proteins and the regulation of novel food products are provided to highlight some of the challenges that will be encountered on the road to commercialization and general acceptance of canola protein as a dietary protein source.

Macroalgae as Protein Sources—A Review on Protein Bioactivity, Extraction, Purification and Characterization

The increased demand for protein sources combined with a decrease in the available land and water resources have led to a growing interest in macroalgae as alternative protein sources. This review focuses on strategies for macroalgae protein extraction, enrichment and characterization. To date, the protein extraction methods applied to algae include enzymatic hydrolysis, physical processes and chemical extraction. Novel methods, such as pulsed electric field, microwave-assisted, pressurized liquid and supercritical fluid extractions, and the application of smart solvents are discussed. An overview of the use of membranes and other processes to generate high-value protein concentrates from algae extracts is also presented, as well as some examples of the methods used for their characterization. The potential bioactivities from macroalgae-derived proteins and peptides, including novel glycoproteins and lectins, are briefly reviewed.

Chemical composition, energy and nutritional values, digestibility and functional properties of defatted flour, protein concentrates and isolates from Carbula marginella (Hemiptera: Pentatomidae) and Cirina butyrospermi (Lepidoptera: Saturniidae)

Edible insects constitute a potential source of alternative proteins as a food supplement. The present study aimed to investigate the chemical composition, energy and nutritional values, the digestibility and functional properties of Carbula marginella (Thunberg) and Cirina butyrospermi (Vuillet) defatted flour, protein concentrates, and isolates. Carbula marginella has shown the highest content of protein (41.44%), lipid (51.92%), calcium (33.92 mg/100 g) and sodium (185.84 mg/100 g) while the highest contents of carbohydrate (34.54%), ash (4.77%), iron (31.27 mg/100 g), magnesium (150.09 mg/100 g), and potassium (1277 mg/100 g) have been observed for C. butyrospermi. Linoleic (30.23%), palmitic (27.54%), oleic (26.41%) and stearic (8.90%) acids were the most dominant fatty acids found in C. marginella. Cirina butyrospermi was characterized by high levels of oleic (27.01%), stearic (21.02%), linolenic (20.42%), palmitic (13.06%), and linoleic (8.01%) acids. Protein and essential amino acid contents of the protein isolates in both insect species were 1.7–2 times higher than that of their defatted flours. The protein isolate of C. marginella exhibited the highest protein digestibility (87.63%), while the highest fat absorption capacity (8.84 g/g) and foaming capacity (48.40%) have been obtained from the protein isolate of C. butyrospermi. These findings indicate that the protein concentrates and isolates of C. marginella and C. butyrospermi have great potential for industrial applications.

Proteins in Food Systems-Bionanomaterials, Conventional and Unconventional Sources, Functional Properties, and Development Opportunities

Recently, food companies from various European countries have observed increased interest in high-protein food and other products with specific functional properties. This review article intends to present proteins as an increasingly popular ingredient in various food products that frequently draw contemporary consumers' attention. The study describes the role of conventional, unconventional, and alternative sources of protein in the human body. Furthermore, the study explores proteins' nutritional value and functional properties, their use in the food industry, and the application of proteins in bionanomaterials. Due to the expected increase in demand for high-protein products, the paper also examines the health benefits and risks of consuming these products, current market trends, and consumer preferences.

Structural modification of whey protein isolate by cinnamaldehyde and stabilization effect on β-carotene-loaded emulsions and emulsion gels

The effect of cinnamaldehyde (CA) on the structure and properties of whey protein isolate (WPI) was investigated. The resultant WPI/CA complex was used as stabilizer to form emulsions and emulsion gels, which were used for the delivery and protection of β-carotene. The particle size and hydrophobicity of WPI solution increased and then decreased with the addition of CA. Circular dichroism showed that CA mainly changed the secondary structure of WPI, with increasing β-fold content from 47.2% to 72.9%. The fluorescence spectra showed that both tryptophan and tyrosine in WPI were involved in the interaction with CA. WPI/CA complex as the stabilizer could form the stable emulsions and emulsion gels, which showed better protection effect on β-carotene, and helped enhance its bioaccessibility. The knowledge provides insights into the development of new multifunctional food ingredients and the enhancement of protein modification in food system.

Structural and foaming properties of whey and soy protein isolates in mixed systems before and after heat treatment

The partial replacement of proteins from animal sources by plant proteins in formulated food products has been proposed as useful to improve sustainability aspects of the products without dramatically changing their techno-functional properties. Although several research groups have published on the gelling properties of mixed systems containing whey and soy protein isolates (WPI and SPI), their foaming properties are much less described. In this context, the main objective of this paper was to evaluate the structural and foaming properties of samples containing different mass ratios of WPI:SPI (100:0, 75:25, 50:50, 25:75 and 0:100) before and after heat treatment. The samples were evaluated according to their solubility, foaming capacity (FC), foam microstructure and foam stability (FS). Before heat treatment, mixing SPI to WPI did not affect the solubility of whey proteins, but, after heat treatment, insoluble co-aggregates were formed. Similar FC was measured for all samples despite their WPI:SPI ratio and the applied heat treatment. The partial replacement of WPI by SPI changed the microstructure of the foams and had an antagonistic effect on the FS of the samples, due to the negative effect of insoluble soy protein aggregates and/or insoluble co-aggregates on the reinforcement of the air-water interfacial film.

In Vitro Digestibility and Antioxidant Activity of Plant Protein Isolate and Milk Protein Concentrate Blends

The replacement of animal with plant proteins in human diets has been increasing in recent years. The impact of blending milk protein concentrate (MPC) with protein isolates from soy (SPI), rice (RPI) and pea (PPI) on the in vitro digestibility and antioxidant activity of the resultant blends was investigated. Different plant protein–MPC blends (i.e., SPI–MPC (25:75), RPI–MPC (50:50) and PPI–MPC (25:75)) were analyzed. The lowest protein digestibility corrected amino acid score (PDCAAS) was associated with RPI (0.70), while the blends had PDCAAS values above 1.00 demonstrating the high digestibility of the proteins in the blends studied. An in vitro simulated gastrointestinal digestion was carried out on the samples. The degree of hydrolysis and gel permeation high performance liquid chromatography profiles showed that the SPI–MPC blend was more extensively digested in the gastric phase compared with the two other blends, while the PPI–MPC and RPI–MPC blends were mainly digested during the intestinal phase. The SPI–MPC digested blend had the highest 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity having a half maximal effective concentration (EC50) of 0.10 ± 0.01 mg/mL. The findings show that blends of plant protein with MPC had higher in vitro digestibility and antioxidant activity compared to the individual plant protein isolates.

Protein deamidation to produce processable ingredients and engineered colloids for emerging food applications

With the ever-increasing demands for functional and sustainable foods from the general public, there is currently a paradigm shift in the food industry toward the production of novel protein-based diet. Food scientists are therefore motivated to search for natural protein sources and innovative technologies to modify their chemical structure for desirable functionality and thus utilization. Deamidation is a viable, efficient, and attractive approach for modifying proteins owing to its ease of operating, specificity, and cost-effective processes. Over the past three decades, the knowledge of protein deamidation for food applications has evolved drastically, including the development of novel approaches for deamidation, such as protein-glutaminase and ion exchange resin, and their practices in new protein substrate. Thanks to deamidation, enhanced functionalities of food proteins from cereals, legumes, milk, oil seeds and others, and thereby their processabilities as food ingredients have been achieved. Moreover, deamidated proteins have been used to fabricate engineered food colloids, including self-assembled protein particles, protein-metallic complexes, and protein-carbohydrate complexes, which have demonstrated tailored physicochemical properties to modulate oral perception, improve gastrointestinal digestion and bioavailability, and protect and/or deliver bioactive nutrients. Novel bioactivity, altered digestibility, and varied allergenicity of deamidated proteins are increasingly recognized. Therefore, deamidated proteins with novel techno-functional and biological properties hold both promise and challenges for future food applications, and a comprehensive review on this area is critically needed to update our knowledge and provide a better understanding on the protein deamidation and its emerging applications.