Microalgae protein digestibility: How to crack open the black box?

Microalgae are booming as a sustainable protein source for human nutrition and animal feed. Nevertheless, certain strains were reported to have robust cell walls limiting protein digestibility. There are several disruption approaches to break down the cell integrity and increase digestive enzyme accessibility. This review's intent is to discuss the digestibility of microalgae proteins in intact cells and after their disruption. In intact single cells, the extent of protein digestibility is chiefly related to cell wall structural properties (differing among strains) as well as digestion method and when added to food or feed protein digestibility changes depending on the matrix's composition. The degree of effectiveness of the disruption method varies among studies, and it is complicated to compare them due to variabilities in digestibility models, strains, disruption method/conditions and their consequent impact on the microalgae cell structure. More exhaustive studies are still required to fill knowledge gaps on the structure of microalgal cell walls and to find efficient and cost-effective disruption technologies to increase proteins availability without hindering their quality.

Analysis of ingredient list and nutrient composition of plant-based burgers available in the global market.

The nutrient composition of plant-based burgers is a key factor when making their purchase/consumption decision to maintain a balanced diet. For this reason, ingredient list and nutritional information of burgers launched in the global market were retrieved from their labels. Products were classified based on the technology development, market position and region of the manufacturer. From the ingredient analysis, we observed a high heterogeneity in the ingredients used, a predominance of soy and wheat as main sources of proteins, and the increasing use of new protein sources (e.g. peas, other types of beans and pseudo-cereals). Oil was the most cited ingredient followed by salt. Nutritional composition varied mainly depending on the region with no clear pattern among countries. To less extent, technology development resulted in traditional products with lower amounts of protein and higher amounts of carbohydrates. Vegan and vegetarian products showed limited differences due to the high intra-heterogenicity.

Consumer acceptability of plant-, seaweed-, and insect-based foods as alternatives to meat: a critical compilation of a decade of research.

There is a growing criticism of meat-based products over environment, animal welfare, and public health. Meat lovers are keeping and adapting their habits, while other consumers are increasingly shifting toward meat alternatives considered as healthier and more sustainable options to replace the animal-based products. This transition gives room in the market to plant-, seaweed-, and insect-based meat products alternatives. Nevertheless, these emerging markets are still facing the challenge of consumers' acceptance and the uncertainty in terms of preferences. This paper focuses on in-depth understanding of consumer perception and acceptability of plant-, seaweed-, and insect-based meat products to get insights on their current situation and future implementation. The main factors and motives influencing the consumer perceptions toward meat alternative products are reported. Further, the consumers' motives and drivers to consume alternative products were highlighted. This review, provides a better understanding of motives and drivers of consumers' acceptance to improve the acceptability of meat alternatives, considering product and country origin of the consumers of meat alternative foods.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2036096.

Bioengineered Enzymes and Precision Fermentation in the Food Industry.

Enzymes have been used in the food processing industry for many years. However, the use of native enzymes is not conducive to high activity, efficiency, range of substrates, and adaptability to harsh food processing conditions. The advent of enzyme engineering approaches such as rational design, directed evolution, and semi-rational design provided much-needed impetus for tailor-made enzymes with improved or novel catalytic properties. Production of designer enzymes became further refined with the emergence of synthetic biology and gene editing techniques and a plethora of other tools such as artificial intelligence, and computational and bioinformatics analyses which have paved the way for what is referred to as precision fermentation for the production of these designer enzymes more efficiently. With all the technologies available, the bottleneck is now in the scale-up production of these enzymes. There is generally a lack of accessibility thereof of large-scale capabilities and know-how. This review is aimed at highlighting these various enzyme-engineering strategies and the associated scale-up challenges, including safety concerns surrounding genetically modified microorganisms and the use of cell-free systems to circumvent this issue. The use of solid-state fermentation (SSF) is also addressed as a potentially low-cost production system, amenable to customization and employing inexpensive feedstocks as substrate.

Novel quality features to expand durum wheat applications.

Durum wheat represents a staple food in the human diet owing to its nutritional and technological features. In comparison to common wheat, durum wheat has higher tolerance to biotic and abiotic stresses. However, its production and culinary uses are limited compared to common wheat. Therefore, significant attention was attributed to upgrading the key quality of durum wheat (i.e., hardness, protein, starch and color). This review intends to put the spotlight on the modification of these properties to create new functionalities suiting a wider range of food applications based on critical compilation of scientific publications. Targeting specific genes has been shown to be a valuable strategy to design novel wheat varieties with higher nutritional value (e.g., high amylose), improved technological properties (e.g., higher glutenin content), attractive appearance (e.g., colored wheat) and new uses (e.g., soft durum wheat for breadmaking). Further efforts are still needed to find efficient ways to stabilize and maintain these properties. © 2022 Society of Chemical Industry.

Non-animal proteins as cutting-edge ingredients to reformulate animal-free foodstuffs: Present status and future perspectives.

Consumer interest in protein rich diets is increasing, with more attention being paid to the protein source. Despite the occurrence of animal proteins in the human diet, non-animal proteins are gaining popularity around the world due to their health benefits, environmental sustainability, and ethical merit. These sources of protein qualify for vegan, vegetarian, and flexitarian diets. Non-animal proteins are versatile, derived mainly from cereals, vegetables, pulses, algae (seaweed and microalgae), fungi, and bacteria. This review's intent is to analyze the current and future direction of research and innovation in non-animal proteins, and to elucidate the extent (limitations and opportunities) of their applications in food and beverage industries. Prior knowledge provided relevant information on protein features (processing, structure, and techno-functionality) with particular focus on those derived from soy and wheat. In the current food landscape, beyond conventionally used plant sources, other plant proteins are gaining traction as alternative ingredients to formulate animal-free foodstuffs (e.g., meat alternatives, beverages, baked products, snack foods, and others). Microbial proteins derived from fungi and algae are also food ingredients of interest due to their high protein quantity and quality, however there is no commercial food application for bacterial protein yet. In the future, key points to consider are the importance of strain/variety selection, advances in extraction technologies, toxicity assessment, and how this source can be used to create food products for personalized nutrition.

The nutritional quality of wholegrain and multigrain breads is not necessarily better than white breads: the case of gluten-free and gluten-containing breads.

Despite the importance of breads through the history, the wide range of options might lead to a choice dilemma from health-conscious consumers when purchasing bread. In this study, commercial white, wholegrain and multigrain regular breads, sold in Europe, were collected, and classified into gluten-free and gluten-containing categories. For gluten-free-breads, no significant differences were found in energy, saturated fatty acids, sugar, fibre and salt between white and wholegrain breads regardless of the mention "multigrain." For gluten-containing, carbohydrates and fibres differed between white and wholegrain breads, while when considering multigrain presence all the nutritional composition varied significantly. Nevertheless, the mentions wholegrain and multigrain on gluten-free and gluten-containing breads do not guarantee a better nutritional quality compared to white bread. Gluten-free breads showed increased fibre, and decreased carbohydrates, sugar and energy which are comparable to gluten-containing wholegrain breads. This underlines the improvement of gluten-free breads and suggests further investigations to increase protein content.

Current and emerging trends in cereal snack bars: implications for new product development.

The change in consumers' lifestyle promoted "snackification" favouring the commercialisation of on-the-go products such as cereal bars (CBs). Manufacturers are encountering challenges to develop healthy, natural, tasty, and affordable CBs. This article focuses on production methods, the current and emerging market trends, and practical implications for developing new CBs. The future of the CBs industry is associated with finding the right balance between nutritional value, sensory attributes, naturalness, and sustainability. Manufactures have a toolbox with a large portfolio of ingredients and processing techniques to develop CBs that can be a meal substitute, a supplement, or a snack.

Current Trends in Ancient Grains-Based Foodstuffs: Insights into Nutritional Aspects and Technological Applications.

For centuries, ancient grains fed populations, but due to their low yield, they were abandoned and replaced by high-yielding species. However, currently, there is a renewed interest in ancient wheat and pseudocereal grains from consumers, farmers, and manufacturers. Ancient wheat such as einkorn, emmer, spelt, and Kamut®, are being reintegrated because of their low fertilizer input, high adaptability and important genetic diversity. New trends in pseudocereal products are also emerging, and they are mostly appreciated for their nutritional outcomes, particularly by the gluten-free market. Toward healthier lifestyle, ancient grains-based foodstuffs are a growing business and their industrialization is taking 2 pathways, either as a raw ingredient or a functional ingredient. This paper deals with these grain characteristics by focusing on the compositional profile and the technological potential.

How Looking for Celiac-Safe Wheat Can Influence Its Technological Properties.

Because of the continuous increase in the prevalence of gluten-related disorders, selection of wheat with a low content of immunogenic gluten epitopes could be an innovative alternative for prevention. In this review, the focus is on literature data concerning the deallergenization tools of wheat, which are mainly related to breeding approaches (classic and advanced) and processing operations (germination and fermentation). Until now, no safe wheat genotype has been identified, whereas decreasing wheat allergenicity is possible. On the other hand, the decrease of gluten or some of its epitopes can strongly affect technological properties. Thus, obtaining celiac-safe gluten without affecting the technological properties of wheat could be considered as a new challenge that scientists will be facing. Celiac-safe wheat-based product development could be a great revolution in the market of foods for special medical purposes. The present paper is aiming to: (a) review the strategies and the approaches used, or that can be used, for developing low allergenic wheat: their utilities and limits were also discussed and (b) screen the impact of gluten reduction or removal on the quality of wheat end-use products.

Overexpression of yeast thioredoxin TRX2 reduces p53-mediated cell death in yeast.

We have previously shown that overexpression of the human tumor suppressor protein P53 causes cell death of the yeast Saccharomyces cerevisiae. P53 overproduction led to transcriptional downregulation of some yeast genes, such as the TRX1/2 thioredoxin system, which plays a key role in cell protection against various oxidative stresses induced by reactive oxygen species (ROS). In the present work, the impact of TRX2 overexpression on apoptosis mediated by p53 overexpression in yeast is investigated. In yeast cells expressing P53 under an inducible promoter together with TRX2 under a strong constitutive promoter, we showed that Tr2p overproduction reduced the apoptotic effect exerted by P53 and increased the viability of the P53-overproducing cells. Furthermore, measurements of ROS amounts by flow cytometry and fluorescence microscopy indicated that the TRX2 protein acted probably through its increased detoxifying activity on the P53-generated ROS. The steady-state level and activity of P53 were not affected by TRX2 overexpression, as shown by western blotting and functional analysis of separated alleles in yeast (FASAY), respectively. The growth inhibitory effect of P53 was partially reversed by the antioxidant N-acetylcysteine. Our data strengthen the idea that overexpression of a single gene (trx2) decreases the p53-mediated cell death by decreasing ROS accumulation.

Clipping Effect on the Grain Nitrogen and Protein Fractions of Ancient and Old Wheats Grown in a Mediterranean Environment.

This study is the first to assess the effects of clipping, cultivar, season, and their interactions on the protein composition of six old and ancient wheat cultivars (n = 6). For this, nitrogen content, the proportion of wheat protein fractions, and the molecular weight distribution of the extractable and unextractable glutenin polymers were investigated as a function of cultivar and clipping in two consecutive seasons. The relationships between genotypic variation in grain nitrogen and protein fraction content under clipping and non-clipping conditions were also assessed. Clipping delayed and shortened the grain filling period of all of the cultivars. The protein composition of some cultivars behaved differently to clipping due to differences in the environmental conditions of S1 (exceptional dry season) and S2 (rainy season). In S1, clipping decreased the ratio of gliadins over glutenins (GLI/GLU) (<1) of Cappelli and Giovanni Paolo, while in S2, clipping improved the GLI/GLU of Giovanni Paolo, Monlis, and Norberto. The unextractable polymeric proteins were not affected by clipping. Khorasan was shown to be indifferent to clipping in S1 and S2. These results suggest that it is possible to have ancient/old wheats suitable for a dual-purpose system, in different climatic conditions, while maintaining good grain quality traits. The increased market demand for ancient and old wheats presents an economic opportunity for farmers who adopt the dual-purpose technique to cultivate these resilient crops again and increase their profit margins and revenues.

Pretreated Green Pea Flour as Wheat Flour Substitutes in Composite Bread Making.

The present study aimed to assess the impact of substituting wheat flour with three different pretreated green pea flour at different addition levels (10-50%) on fresh bread quality during a 7-day storage period. Dough and bread enriched with conventionally milled (C), pre-cooked (P), and soaked under-pressure-steamed (N) green pea flour were evaluated for their rheological, nutritional, and technological features. Compared to wheat flour, legumes had lower viscosity but higher water absorption, development time, and lower retrogradation. Bread made with C10 and P10 showed similar specific volume, cohesiveness, and firmness to the control, whereas addition levels beyond 10% decreased specific volume and increased firmness. During storage, incorporating legume flour (10%) delayed staling. Composite bread increased proteins and fiber. C30 had the lowest rate of starch digestibility, while pre-heated flour increased starch digestibility. In conclusion, P and N can be considered valuable ingredients for making soft and stable bread.

A sensory study on consumer valuation for plant-based meat alternatives: What is liked and disliked the most?

The food sector has witnessed a surge in the production of plant-based meat alternatives that aim to mimic various attributes of traditional animal products. However, overall sensory appreciation remains low. This study employed open-ended questions, preference ranking, and an identification question to analyze sensory drivers and barriers to liking four burger patties, i.e., two plant-based (one referred to as pea protein burger and one referred to as animal-like protein burger), one hybrid meat-mushroom, and one 100 % beef burger. Untrained participants (n = 175) were randomly assigned to blind or informed conditions in a between-subject study. The main objective was to evaluate the impact of providing information about the animal/plant-based protein source/type, and to obtain product descriptors and liking/disliking levels from consumers. Results from the ranking tests for blind and informed treatments showed that the animal-like protein was the most preferred product, followed by the 100 % beef burger. Moreover, in the blind condition, there was no significant difference in preferences between the beef burger and the hybrid and pea protein burgers. In the blind tasting, people preferred the pea protein burger over the hybrid one, contrary to the results of the informed tasting, which implies the existence of affecting factors other than pure hedonistic enjoyment. In the identification question, although consumers correctly identified the beef burger under the blind condition, they still preferred the plant-based 'animal-like' burger.

Fermentation for Designing Innovative Plant-Based Meat and Dairy Alternatives.

Fermentation was traditionally used all over the world, having the preservation of plant and animal foods as a primary role. Owing to the rise of dairy and meat alternatives, fermentation is booming as an effective technology to improve the sensory, nutritional, and functional profiles of the new generation of plant-based products. This article intends to review the market landscape of fermented plant-based products with a focus on dairy and meat alternatives. Fermentation contributes to improving the organoleptic properties and nutritional profile of dairy and meat alternatives. Precision fermentation provides more opportunities for plant-based meat and dairy manufacturers to deliver a meat/dairy-like experience. Seizing the opportunities that the progress of digitalization is offering would boost the production of high-value ingredients such as enzymes, fats, proteins, and vitamins. Innovative technologies such as 3D printing could be an effective post-processing solution following fermentation in order to mimic the structure and texture of conventional products.

Protein Quality and Protein Digestibility of Vegetable Creams Reformulated with Microalgae Inclusion.

Microalgae are considered a valuable source of proteins that are used to enhance the nutritional value of foods. In this study, a standard vegetable cream recipe was reformulated through the addition of single-cell ingredients from Arthrospira platensis (spirulina), Chlorella vulgaris, Tetraselmis chui, or Nannochloropsis oceanica at two levels of addition (1.5% and 3.0%). The impact of microalgae species and an addition level on the amino acid profile and protein in vitro digestibility of the vegetable creams was investigated. The addition of microalgae to vegetable creams improved the protein content and the amino acid nutritional profile of vegetable creams, whereas no significant differences were observed in protein digestibility, regardless of the species and level of addition, indicating a similar degree of protein digestibility in microalgae species despite differences in their protein content and amino acid profile. This study indicates that the incorporation of microalgae is a feasible strategy to increase the protein content and nutritional quality of foods.

The realm of plant proteins with focus on their application in developing new bakery products.

Plant proteins are spreading due to growing environmental, health and ethical concerns related to animal proteins. Proteins deriving from cereals, oilseeds, and pulses are witnessing a sharp growth showing a wide spectrum of applications from meat and fish analogues to infant formulations. Bakery products are one of the biggest markets of alternative protein applications for functional and nutritional motives. Fortifying bakery products with proteins can secure a better amino-acids profile and a higher protein intake. Conventional plant proteins (i.e., wheat and soy) dominate the bakery industry, but emerging sources (i.e., pea, chickpea, and faba) are also gaining traction. Each protein brings specific functional properties and nutritional value. Therefore, this chapter gives an overview of the main features of plant proteins and discusses their impact on the quality of bakery products.

Vegan Egg: A Future-Proof Food Ingredient?

Vegan eggs are designed with the aim to provide a healthier and more sustainable alternative to regular eggs. The major drivers of this industry are the increasing prevalence of egg allergies, awareness towards environmental sustainability, and the shift to vegan diets. This study intends to discuss, for the first time, the vegan egg market, including their formulation, nutritional aspects, and some applications (i.e., mayonnaise and bakery products). Recreating the complete functionality of eggs using plant-based ingredients is very challenging due to the complexity of eggs. Current, but scarce, research in this field is focused on making mixtures of plant-based ingredients to fit specific food formulations. Nutritionally, providing vegan eggs with similar or higher nutritional value to that of eggs can be of relevance to attract health-conscious consumers. Claims such as clean labels, natural, vegan, animal-free, gluten-free, and/or cholesterol-free can further boost the position of vegan eggs in the market in the coming year. At present, this market is still in its infancy stages, and clear regulations of labeling, safety, and risk assessment are deemed mandatory to organize the sector, and protect consumers.

Meat alternatives: A proofed commodity?

The demand for meat alternatives has been growing in the recent years and it is expected to keep expanding. Motives driving this growth are diverse and are mostly related to the health and ethical concerns over animal welfare and the possible impact of meat production on the environment. Meat alternatives are not anymore a niche market (i.e., vegetarians and vegans) but going mainstream (also consumed by meat eaters and flexitarians). This can be attributed to advances in formulations and ingredients and innovative technologies resulting in improved quality of products. This chapter summarizes the current knowledge about meat alternatives (from plant, fungi or/and algae). Plant-based alternatives are already a proofed commodity with a wide range of products available in the market. The search for more sustainable sources had put the spotlight on other sources such as fungi and algae due to their limited need to land, energy and water for biomass production. Fungi-based alternatives are steps ahead of those algae-based owing to fungi neutral flavor, comparable nutritional profile to meat and no need to masking agents. Consumer acceptance is still a key challenge boosting research and development efforts to ensure a better quality, affordability, and sustainability.

Algae as Nutritional and Functional Food Sources.

Algae are a large and diverse group of autotrophic eukaryotic and photosynthetic aquatic organisms [...].