Structural properties of pea proteins (Pisum sativum) for sustainable food matrices.

Pea proteins are widely used as a food ingredient, especially in sustainable food formulations. The seed itself consists of many proteins with different structures and properties that determine their structure-forming properties in food matrices, such as emulsions, foams, and gels. This review discusses the current insights into the structuring properties of pea protein mixtures (concentrates, isolates) and the resulting individual fractions (globulins, albumins). The structural molecular features of the proteins found in pea seeds are discussed and based on this information, different structural length scales relevant to foods are reviewed. The main finding of this article is that the different pea proteins are able to form and stabilize structural components found in foods such as air-water and oil-water interfaces, gels, and anisotropic structures. Current research reveals that each individual protein fraction has unique structure-forming properties and that tailored breeding and fractionation processes will be required to optimize these properties. Especially the use of albumins, globulins, and mixed albumin-globulins proved to be useful in specific food structures such as foams, emulsions, and self-coacervation, respectively. These new research findings will transform how pea proteins are processed and being used in novel sustainable food formulations in the future.

Insights into characterizing and producing anisotropic food structures.

Besides the flavor profile of food, texture plays a major role in terms of the acceptance and likeability of food products. In contrast to gel-like homogenous isotropic structures, where the characterization is established and structure-texture mechanisms are well understood, there is still a lack of knowledge in the field of anisotropic complex food matrices. Food systems that show anisotropic properties in terms of macroscopic mechanical anisotropy as in grown meat, or mixed complex systems where anisotropic shaped particles or fibers are embedded into an isotropic matrix are challenging to characterize, hence the structure-texture correlation is not trivial to understand. In this paper, we bring together the state of the art of different anisotropic structures as a source of food, their formation in terms of structured plant proteins, and consequently the structure-texture correlation of those. Characteristic terms and properties to differentiate between anisotropic systems are introduced with the purpose to facilitate characterization of those. Based on the here provided terms and characteristics, further studies toward understanding such systems and their perception can be conducted. Beyond that, a first opinion on crucial influencing factors on the perception of anisotropic systems and their mechanistic background is provided.

Technologies for sustainable heat generation in food processing.

The utilization of heat is one of the foundations of modern food processing. At present, boilers that operate on fossil fuels are still dominating the generation of hot water, steam, and hot air in the food industry. In light of sustainability goals and carbon taxes as well as international efforts to reduce the dependence on natural gas, new technologies are needed to lower the greenhouse gas emissions related to thermal processing of foods. This review discusses important technologies that could serve as a replacement for conventional fossil fuel boilers in the future. These technologies are based on electricity, geothermal energy (direct/indirect use), and electricity to hydrogen conversion and include fuel cells, microturbines, engines, electrical boilers, heat pumps, radiation, and use of geothermal energy. The majority of these technologies are already available for implementation at larger scales and emissions are generally lower compared to burning fossil fuels. At present, major obstacles, such as low fossil fuel prices, still exist that prevent the widespread adoption of more sustainable heating technologies. However, the direct transformation of electrical energy and utilization of geothermal energy for heating purposes seem promising and should be more frequently installed in the future, whereas the use of H2 obtained through electrolysis as a transportable source of energy may also serve as a source of thermal energy where it is useful to generate electricity and heat on the production site or where the availability of electricity is limited.

The science of plant-based foods: Constructing next-generation meat, fish, milk, and egg analogs.

Consumers are increasingly demanding foods that are more ethical, sustainable and nutritious to improve the health of themselves and the planet. The food industry is currently undergoing a revolution, as both small and large companies pivot toward the creation of a new generation of plant-based products to meet this consumer demand. In particular, there is an emphasis on the production of plant-based foods that mimic those that omnivores are familiar with, such as meat, fish, egg, milk, and their products. The main challenge in this area is to simulate the desirable appearance, texture, flavor, mouthfeel, and functionality of these products using ingredients that are isolated entirely from botanical sources, such as proteins, carbohydrates, and lipids. The molecular, chemical, and physical properties of plant-derived ingredients are usually very different from those of animal-derived ones. It is therefore critical to understand the fundamental properties of plant-derived ingredients and how they can be assembled into structures resembling those found in animal products. This review article provides an overview of the current status of the scientific understanding of plant-based foods and highlights areas where further research is required. In particular, it focuses on the chemical, physical, and functional properties of plant-derived ingredients; the processing operations that can be used to convert these ingredients into food products; and, the science behind the formulation of vegan meat, fish, eggs, and milk alternatives.

Standardized methods for testing the quality attributes of plant-based foods: Milk and cream alternatives.

The food industry is creating a diverse range of plant-based alternatives to dairy products, such as milks, creams, yogurts, and cheeses due to the increasing demand from consumers for more sustainable, healthy, and ethical products. These dairy alternatives are often designed to mimic the desirable physicochemical, functional, and sensory properties of real dairy products, such as their appearance, texture, mouthfeel, flavor, and shelf-life. At present, there is a lack of systematic testing methods to characterize the properties of plant-based dairy alternatives. The purpose of this review is to critically evaluate existing methods and recommend a series of standardized tests that could be used to quantify the properties of fluid plant-based milk alternatives (milk and cream). These methods could then be used to facilitate the design of milk alternatives with somewhat similar attributes as real dairy milk by comparing their properties under standardized conditions. Moreover, they could be used to facilitate comparison of the properties of milk alternatives developed in different laboratories.

Cultivation and downstream processing of microalgae and cyanobacteria to generate protein-based technofunctional food ingredients.

Microalgae are unicellular microorganisms that can be rich in proteins and are therefore a valuable ingredient in different foods. So far microalgae are mainly utilized in foods in low concentrations as a whole-cell ingredient even though it is known that proteins extracted from microalgae can possibly posess various technofunctional properties, such as high protein solubility, emulsification, foaming, and gelation properties. The widespread usage of protein-rich ingredients obtained from microalgae is for the most part prevented by the high price of the biomass, the lack of efficient downstream processes, and the adverse taste. The aim of this review is to give insights into the fundamental properties of the growth and processing of microalgae, highlight the advantages of microalgae ingredients and show potential applications based on the technofunctional, nutritional and sensory properties that were reported. Moreover, the existing challenges and knowledge gaps that hinder the application of microalgal proteins in foods are discussed.

Sensory properties of aqueous dispersions of protein-rich extracts from Chlorella protothecoides at neutral and acidic pH.

BACKGROUND: Water-soluble proteins extracted from the heterotrophically cultivated microalga Chlorella protothecoides have been shown to have a good solubility over a broad pH range, which makes them a promising candidate for beverage formulations. This study investigated the sensory properties of dispersions of a protein-rich extract from C. protothecoides at neutral and pH 3. RESULTS: Sensory acceptance tests of the pure extract revealed an overall low acceptance at pH 7 without sucrose addition. Sensory acceptance was significantly (P ≤ 0.05) increased by lowering the pH to 3 with citric acid, and the addition of 50 g kg-1 sucrose. Here, overall positive sensory acceptance ratings were achieved up to a protein extract concentration of 40 g kg-1 . Basic taste evaluations showed only low bitterness scores and no significant (P > 0.05) increase in bitterness with decreasing pH. CONCLUSION: It is suggested that protein-rich extracts from C. protothecoides have promising sensory properties in beverage formulations. © 2019 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sustainable media feedstocks for cellular agriculture.

The global food system is shifting towards cellular agriculture, a second domestication marked by cultivating microorganisms and tissues for sustainable food production. This involves tissue engineering, precision fermentation, and microbial biomass fermentation to establish food value chains independent of traditional agriculture. However, these techniques rely on growth media sourced from agricultural, chemical (fossil fuels), and mining supply chains, raising concerns about land use competition, emissions, and resource depletion. Fermentable sugars, nitrogen, and phosphates are key ingredients derived from starch crops, energy-intensive fossil fuel based processes, and finite phosphorus resources, respectively. This review explores sustainable alternatives to reduce land use and emissions associated with cellular agriculture media ingredients. Sustainable alternatives to first generation sugars (lignocellulosic substrates, sidestreams, and gaseous feedstocks), sustainable nitrogen sources (sidestreams, green ammonia, biological nitrogen fixation), and efficient use of phosphates are reviewed. Especially cellulosic sugars, gaseous chemoautotrophic feedstocks, green ammonia, and phosphate recycling are the most promising technologies but economic constraints hinder large-scale adoption, necessitating more efficient processes and cost reduction. Collaborative efforts are vital for a biotechnological future grounded in sustainable feedstocks, mitigating competition with agricultural land and emissions.

Utilizing the pH-Shift Method for Isolation and Nutritional Characterization of Mantis Shrimp (Oratosquilla nepa) Protein: A Strategy for Developing Value-Added Ingredients.

This study focused on the production of protein isolates from mantis shrimp (MS). The pH-shift method was investigated to understand its impact on the protein yield, quality, and properties of the produced isolates. The first step was determining how the pH affected the protein solubility profile, zeta potential, and brown discoloration. The pH-shift process was then established based on the maximum and minimum protein solubilization. The solubilization pH had a significant impact on the mass yield and color of the produced protein, with a pH of 1.0 producing the maximum mass in the acidic region, whereas a maximum was found at a pH of 12.0 in the alkaline region (p < 0.05). Both approaches yielded mantis shrimp protein isolates (MPIs) with precipitation at a pH of 4.0 and a mass yield of around 25% (dw). The TCA-soluble peptide and TBARS levels were significantly lower in the MPI samples compared to MS raw material (p < 0.05). The MPIs maintained essential amino acid index (EAAI) values greater than 90%, indicating a high protein quality, and the pH-shift procedure had no negative impact on the protein quality, as indicated by comparable EAAI values between the mantis shrimp protein isolate extract acid (MPI-Ac), mantis shrimp protein isolate extract alkaline (MPI-Al), and MS raw material. Overall, the pH-shift approach effectively produced protein isolates with favorable quality and nutritional attributes.

Microbial gas fermentation technology for sustainable food protein production.

The development of novel, sustainable, and robust food production technologies represents one of the major pillars to address the most significant challenges humanity is going to face on earth in the upcoming decades - climate change, population growth, and resource depletion. The implementation of microfoods, i.e., foods formulated with ingredients from microbial cultivation, into the food supply chain has a huge potential to contribute towards energy-efficient and nutritious food manufacturing and represents a means to sustainably feed a growing world population. This review recapitulates and assesses the current state in the establishment and usage of gas fermenting bacteria as an innovative feedstock for protein production. In particular, we focus on the most promising representatives of this taxon: the hydrogen-oxidizing bacteria (hydrogenotrophs) and the methane-oxidizing bacteria (methanotrophs). These unicellular microorganisms can aerobically metabolize gaseous hydrogen and methane, respectively, to provide the required energy for building up cell material. A protein yield over 70% in the dry matter cell mass can be reached with no need for arable land and organic substrates making it a promising alternative to plant- and animal-based protein sources. We illuminate the holistic approach to incorporate protein extracts obtained from the cultivation of gas fermenting bacteria into microfoods. Herein, the fundamental properties of the bacteria, cultivation methods, downstream processing, and potential food applications are discussed. Moreover, this review covers existing and future challenges as well as sustainability aspects associated with the production of microbial protein through gas fermentation.

Next-Generation Plant-Based Foods: Challenges and Opportunities.

Owing to environmental, ethical, health, and safety concerns, there has been considerable interest in replacing traditional animal-sourced foods like meat, seafood, egg, and dairy products with next-generation plant-based analogs that accurately mimic their properties. Numerous plant-based foods have already been successfully introduced to the market, but there are still several challenges that must be overcome before they are adopted by more consumers. In this article, we review the current status of the science behind the development of next-generation plant-based foods and highlight areas where further research is needed to improve their quality, increase their diversity, and reduce their cost, including improving ingredient performance, developing innovative processing methods, establishing structure-function relationships, and improving nutritional profiles. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 15 is April 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Strategies to Reduce Fossil Fuel Use in Food Manufacturing.

Our food production relies on the input of fossil fuels to create the high variety of different food products currently on the market. This reliance has caused challenges due to the inherent emissions generated by the combustion of fossil fuels and the dependence of many countries on only a small number of fossil fuel suppliers. This review aims to look at these challenges and discusses several mitigation strategies to reduce the usage of fossil fuels in the food processing part of the food value chain. In this specific step, there is substantial potential to change the type of energy that is used to transform the raw materials into an edible food matrix because the operations mainly include processes that rely often on natural gas for heating and electricity that is used for machine operation and cooling. Both energy sources can be replaced by clean and renewable alternatives, especially with alternative heating options such as geothermal heating and electrical boilers being installed and offered more frequently. However, short-term solutions like energy reduction through process optimization and the integration of smart sensors can also help to reduce the overall energy use in the short term. These strategies are outlined in this review along with in-depth analyses of the types of energy used in food processing, the available clean and renewable energy technologies that do not rely on fossil fuels, and the current hurdles and limitations. It becomes evident that most of the required technologies are already available on the market and that considerable investments are necessary to implement a comprehensive energy strategy that does not rely on fossil fuels in food manufacturing. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 15 is April 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Extraction, Composition, Functionality, and Utilization of Brewer's Spent Grain Protein in Food Formulations.

In recent years, brewer's spent grain (BSG) has gained attention as a plant-based protein source because it occurs in large quantities as a by-product of beer brewing. BSG can contribute to future food requirements and support the development of a circular economy. In light of the dynamic developments in this area, this review aims to understand the proteins present in BSG, and the effect of extraction techniques and conditions on the composition, physicochemical, and techno-functional properties of the obtained protein extracts. The water-insoluble hordeins and glutelins form the major protein fractions in BSG. Depending on the beer brewing process, the extraction technique, and conditions, the BSG protein isolates predominantly contain B, C, and ϒ hordeins, and exhibit a broad molecular weight distribution ranging between <5 kDa and >250 kDa. While the BSG isolates obtained through chemical extraction methods seem promising to obtain gelled food products, physical and enzymatic modifications of BSG proteins through ultrasound and proteolytic hydrolysis offer an effective way to produce soluble and functional protein isolates with good emulsifying and foaming capabilities. Specifically tailored protein extracts to suit different applications can thus be obtained from BSG, highlighting that it is a highly valuable protein source.

A Novel Approach for the Production of Mildly Salted Duck Egg Using Ozonized Brine Salting.

Salted eggs are normally produced by treating fresh duck eggs with a high salt concentration in order to acquire distinctive features and excellent preservation capabilities as a result of a series of physicochemical changes. This method, however, induces a high salt content in the product. The goal of this research was to create a new way of producing mildly salted duck eggs using ozonized brine salting. The brine was made by dissolving NaCl (26% w/v) in water or ozonized water at a concentration of 50 ng ozone/mL (ozonized brine). Compared to brine, ozonized brine resulted in salted eggs with reduced ultimate salt levels in both albumen and yolk (p < 0.05). The Haugh unit of the salted eggs generated by ozonized brine was similar to that of the brine-made salted egg group (p > 0.05), but the salted egg produced by ozonized brine matured and solidified faster because the yolk index (0.62) was higher than that of the brine (0.55) (p < 0.05). The final pH of salted eggs generated with brine and ozonized brine was not different (p > 0.05). Regardless of the salting method, both salted eggs contained low TVB-N content (<10 mg/100 g). Ozonized brine increased the protein carbonyl content in salted albumen, which may be related to albumen protein aggregation and served as a salt diffusion barrier. However, after boiling the salted egg, the protein carbonyl level was comparable to that of fresh albumen. The TBARS levels of boiled salted albumen prepared with brine and ozonized brine were comparable (p > 0.05), and the value was extremely low (~0.1 mg MDA equivalent/kg). The TBARS value of the salted yolk prepared with brine was higher than that of the salted yolk prepared with ozonized brine (p < 0.05), and both salted yolks showed increased TBARS values after cooking (p < 0.05). The albumen and yolk components appeared to be altered similarly by both brine and ozonized brine, according to the FTIR spectra. Furthermore, the appearance and color of the yolk and albumen in salted eggs prepared with brine and ozonized brine were comparable. Boiled salted albumen produced with ozonized brine had a denser structure with fewer voids. This could be attributed to the final salted egg's lower salt content and lower salt diffusion rate, which were likely caused by protein oxidation and, as a result, aggregation when ozonized brine was used.

The Effect of Multistage Refinement on the Bio-Physico-Chemical Properties and Gel-Forming Ability of Fish Protein Isolates from Mackerel (Rastrelliger kanagurta).

The objective of this research was to improve the protein extraction processes of Rastrelliger kanagurta (Indian mackerel) to generate protein isolate with enhanced bio-physico-chemical properties and gel-forming ability. To achieve this, two novel approaches were designed that utilized an additional alkaline separation step and were compared to a conventional process: acid solubilization → alkaline solubilization → pI and acid solubilization → pI → alkaline solubilization. The novel extraction designs resulted in a lower lipid content, lipid oxidation, and TCA-soluble peptides, as well as improving the color and sensory features of the refined proteins, which corresponded to the lowest total heme pigments (p < 0.05). Furthermore, the protein isolate recovered with the modified processes showed significant changes in biochemical properties (decreases in Ca2+-ATPase activity/reactive sulfhydryl content and an increase in surface hydrophobicity) and dynamic rheological behavior. As a result, by altering the extraction procedure it was possible to obtain improved gel characteristics such as gel strength, color, expelled moisture, and improved gel microstructure. Moreover, this study demonstrated that the gel network was partly stabilized by disulfide bonds, according to SDS-PAGE. Overall, this study demonstrates that by optimizing protein extraction procedures a considerable improvement in quality can be achieved and that an additional alkaline extraction after isoelectric point precipitation results in the optimized gel-forming ability of mackerel proteins.

Mushroom-Legume-Based Minced Meat: Physico-Chemical and Sensory Properties.

A growing number of health-conscious consumers are looking for animal protein alternatives with similar texture, appearance, and flavor. However, research and development still needs to find alternative non-meat materials. The aim of this study was to develop a mushroom-based minced meat substitute (MMMS) from edible Pleurotus sajor-caju (PSC) mushrooms and optimize the concentration of chickpea flour (CF), beetroot extract, and canola oil. CF was used to improve the textural properties of the MMMS by mixing it with PSC mushrooms in ratios of 0:50, 12.5:37.5, 25:25, 37.5:12.5, and 50:0. Textural and sensory attributes suggest that PSC mushrooms to CF in a ratio of 37.5:12.5 had better textural properties, showing hardness of 2610 N and higher consumer acceptability with protein content up to 47%. Sensory analysis suggests that 5% (w/w) canola oil showed the most acceptable consumer acceptability compared to other concentrations. Color parameters indicate that 0.2% beetroot extract shows higher whiteness, less redness, and higher yellowness for both fresh and cooked MMMS. This research suggests that MMMS containing PSC, CF, canola oil, and beetroot extract could be a suitable alternative and sustainable food product which may lead to higher consumer adoption as a meat substitute.

Pickering emulsion stabilized by hydrolyzed starch: Effect of the molecular weight.

HYPOTHESIS: The emulsifying ability of starch is influenced by its molecular weight. Reducing the molecular weight of starch is expected to influence interfacial adsorption and membrane elasticities, thereby affecting its emulsifying ability through Pickering effects. Hence, it should be possible to tailor the emulsifying ability of starch by adjusting its molecular weight. EXPERIMENTS: Waxy corn starch (CS) and rice starch (RS) were hydrolyzed with pullulanase to obtain high (HM) and low molecular weight (LM) fractions. After the molecular weight was determined by size exclusion chromatography, the fractions were used to prepare model oil-in-water emulsions. The stability, microscopy, and particle size of the emulsions were characterized, and the underlying emulsification mechanism was subsequently studied through dynamic laser scattering, surface tension analysis, interfacial rheology, and Pearson's correlation calculations. FINDINGS: In the molecular weight range obtained in this study, the smaller the molecular weight of starch, the stronger its emulsifying ability. The decrease in molecular weight resulted in considerable different adsorption and interfacial elasticities with smaller fractions occupying less area on the interface and forming interfaces with higher elasticities, resulting in higher stabilities through Pickering effects. Results thus suggest that the emulsifying ability of starch may be tailored by adjusting its molecular weight.

Thermal and acidic denaturation of phycocyanin from Arthrospira platensis: Effects of complexation with λ-carrageenan on blue color stability.

The pH and temperature sensitivity of the natural blue pigment phycocyanin from Arthrospira platensis limits its application as food colorant. This study examines the effect of protein stabilization by the anionic polysaccharide λ-carrageenan on phycocyanins color appearance at pH 2.5-6.0, unheated and after heat treatments (70/90 °C). Electrostatic interactions, hydrophobic interactions, hydrogen bonds and disulfide-bridges were assessed by adding NaCl, urea and dithiothreitol (DTT) to the samples. Measurements of the zeta potential, transmittance and two-dimensional gel electrophoresis coupled to mass spectrometry confirmed electrostatic interactions around the zero surface charge of phycocyanin over a broad pH range (∼4.1-6.4). Despite a color shift towards turquoise, the color remained stable during heating, especially below of pH 3.5. Precipitation was inhibited over the entire pH range. Overall, electrostatic complexation of phycocyanin and λ-carrageenan is a promising technique to stabilize proteinaceous colorants, helping to reduce food waste and foster a shift to renewable materials.

A brief review of the science behind the design of healthy and sustainable plant-based foods.

People are being encouraged to consume more plant-based foods to reduce the negative impacts of the modern food supply on human and global health. The food industry is therefore creating a new generation of plant-based products to meet this demand, including meat, fish, egg, milk, cheese, and yogurt analogs. The main challenge in this area is to simulate the desirable appearance, texture, flavor, mouthfeel, nutrition, and functionality of these products using healthy, affordable, and sustainable plant-derived ingredients, such as lipids, proteins, and carbohydrates. The molecular and physicochemical properties of plant-derived ingredients are very different from those of animal-derived ones. It is therefore critical to understand the fundamental attributes of plant-derived ingredients and how they can be assembled into structures resembling those found in animal products. This short review provides an overview of the current status of the scientific understanding of plant-based foods and highlights areas where further research is required. In particular, it focuses on the chemical, physical, and functional properties of plant ingredients; the processing operations that can be used to convert these ingredients into food products; and the science behind the creation of some common plant-based foods, namely meat, egg, and milk analogs.

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.