Oat proteins as emerging ingredients for food formulation: where we stand?

Effects of molecular structure and charge state on the foaming and emulsifying properties of Spirulina protein isolates

Microalgae protein holds great potential for various applications in the food industry. However, the current knowledge regarding microalgae protein remains limited, with little information available on its functional properties. Furthermore, the relationship between its molecular structure and functional properties is not well defined, which limits its application in food processing. This study aims to addresses these gaps though an analysis of the emulsibility and foamability of various soluble protein isolates from two species of Spirulina (Arthospira platensis and Spirulina platensis), and the functional properties of Spirulina protein isolates in relation to its molecular structure and charge state. Results revealed that the degree of cross-linking and aggregation or folding and curling of protein tertiary structures was higher in the highly soluble Spirulina protein isolates (AP50% and SP50%) than in the low-solubility isolates (AP30% and SP30%). The foaming capacity (FC) of AP50% and SP50% was found to be lower than that of AP30% and SP30%. Spirulina protein isolates can stably adsorb at the air-water interface for at least 20 min and possessed good interfacial activity. A high pH value was found to promote cross-linking of protein particles at the oil-water interface, thereby reinforcing the internal network structure of emulsions and increasing viscosity. These findings provide preliminary insights for potential applications of Spirulina protein isolates in food production, especially towards quality improvement.

Improved bioavailability and antioxidation of β-carotene-loaded biopolymeric nanoparticles stabilized by glycosylated oat protein isolate

The limited bioavailability of β-carotene hinders its potential application in functional foods, despite its excellent antioxidant properties. Protein-based nanoparticles have been widely used for the delivery of β-carotene to overcome this limitation. However, these nanoparticles are susceptible to environmental stress. In this study, we utilized glycosylated oat protein isolate to prepare nanoparticles loaded with β-carotene through the emulsification-evaporation method, aiming to address this challenge. The results showed that β-carotene was embedded into the spherical nanoparticles, exhibiting relatively high encapsulation efficiency (86.21 %) and loading capacity (5.43 %). The stability of the nanoparticles loaded with β-carotene was enhanced in acidic environments and under high ionic strength. The nanoparticles offered protection to β-carotene against gastric digestion and facilitated its controlled release (95.76 % within 6 h) in the small intestine, thereby leading to an improved in vitro bioavailability (65.06 %) of β-carotene. This improvement conferred the benefits on β-carotene nanoparticles to alleviate tert-butyl hydroperoxide-induced oxidative stress through the upregulation of heme oxygenase-1 and NAD(P)H quinone dehydrogenase 1 expression, as well as the promotion of nuclear translocation of nuclear factor-erythroid 2-related factor 2. Our study suggests the potential for the industry application of nanoparticles based on glycosylated proteins to effectively deliver hydrophobic nutrients and enhance their application.

Oat protein modulates cholesterol metabolism and improves cardiac systolic function in high fat, high sucrose fed rats

Oats are recognized to provide many health benefits that are mainly associated with its dietary fibre, β-glucan. However, the protein derived from oats is largely understudied with respect to its ability to maintain health and attenuate risk factors of chronic diseases. The goal of the current study was to investigate the metabolic effects of oat protein consumption in lieu of casein as the protein source in high fat, high sucrose (HF/HS) fed Wistar rats. Four-week-old rats were divided into three groups and were fed three different experimental diets: a control diet with casein as the protein source, an HF/HS diet with casein, or an HF/HS diet with oat protein for 16 weeks. Heart structure and function were determined by echocardiography. Blood pressure measurements, an oral glucose tolerance test, and markers of cholesterol metabolism, oxidative stress, inflammation, and liver and kidney damage were also performed. Our study results show that incorporation of oat protein in the diet was effective in preserving systolic heart function in HF/HS fed rats. Oat protein significantly reduced serum total and low-density lipoprotein cholesterol levels. Furthermore, oat protein normalized liver HMG-CoAR activity, which, to our knowledge, is the first time this has been reported in the literature. Therefore, our research suggests that oat protein can provide hypocholesterolemic and cardioprotective benefits in a diet-induced model of metabolic syndrome.

Macromolecular characterization of high β-glucan oat lines

Oat (Avena sativa) is a cereal grain rich in fibers, proteins, vitamins and minerals. Oats have been linked to several health benefits, such as lowering blood cholesterol levels, counteracting cardiovascular disease and regulating blood sugar levels. This study aimed to characterize two new oat lines with high β-glucan content emanating from ethyl methyl sulphonate mutagenesis on the Lantmännen elite variety Belinda. Two of the mutated lines, and the mother variety Belinda, were profiled for β-glucan, arabinoxylan, total dietary fiber and starch composition. In addition, total lipid and protein content, amino acid composition and β-glucan molecular weights were analyzed. The high levels of β-glucan resulted in a significant increase in total dietary fiber, but no correlation could be established between higher or lower levels of the assayed macromolecules, i.e., between arabinoxylan-, starch-, lipid- or protein levels in the mutated lines compared to the reference. The results indicate separate biosynthetic pathways for β-glucans and other macromolecules and an independent regulation of the different polysaccharides studied. Therefore, ethyl methyl sulphonate mutagenesis can be used to increase levels of multiple macromolecules in the same line.

Structural modification of oat protein by thermosonication combined with high pressure for O/W emulsion and model salad dressing production

Oat protein is becoming an important ingredient in beverages and formulated foods owing to its high nutritive value and bland flavor; yet, its functionality remains largely unexplored. This study sought to enhance the surface activity of oat protein isolate (OPI) through high-intensity ultrasound (HIU; at 20 or 60 °C) combined with high pressure homogenization (HP; 30 MPa) treatments. Sonication disturbed the protein conformation and significantly improved surface hydrophobicity (19.7%) and ζ-potential (15.7%), which were further augmented by subsequent HP (P < 0.05). Confocal microscopy revealed a uniform oil droplet distribution in emulsions prepared with HIU+HP combination treated OPI, and the oil droplet size decreased up to 35.6% when compared to that of non-treated OPI emulsion (d = 1718 nm). Emulsifying activity was greater for HIU+HP than for HIU, and the viscosity followed a similar trend. Moreover, while emulsions prepared with HIU or HP treated OPI were more stable than control, the 60 °C HIU+HP combination treatment yielded the maximum stability. In corroboration, a model salad dressing prepared from HIU+HP treated OPI displayed a homogenous oil droplet distribution and an improved viscosity. Therefore, thermosonication combined with high pressure homogenization may be suitable for salad dressings and other oil-imbedded food products.

Production and Characterization of a Novel Symbiotic Plant-based Beverage Rich in Antioxidant Phenolic: Mung Bean and Rye Sprouts

There is an increasing demand for non-dairy probiotic food due to the constraints associated with dairy probiotics. In this study, a co-culture synbiotic beverage was prepared using a mixture of mung bean and rye sprouts inoculated with Lactobacillus plantarum (B-28) and Lactobacillus casei (B-29), along with inulin and oligofructose as prebiotics. The effects of prebiotic addition and starter culture on the survival of probiotics during cold storage and simulated gastric conditions were examined. Additionally, titratable acidity, pH, phenolic content, antioxidant activity, and sensory characteristics were evaluated over a 28-day period. The resulting product demonstrated good survival for L. casei (107 CFU.ml-1) and L. plantarum (106 CFU.ml-1) after 4 weeks under refrigeration with no significant changes in quality. The samples exhibited significantly high total phenolic content (TPC), ranging from 19.18 to 25.75 mg GAE/100 mL, which L. casei-containing drinks exhibited the highest TPC activity (p < 0.05). All treatments showed a significant reduction in probiotic survival during gastrointestinal digestion in the laboratory conditions (p < 0.05), although more than 50% survival was observed for all strains. The addition of prebiotics to the beverages led to a significant decrease in phenolic content (p < 0.05), but improved sensory scores. The highest turbidity was observed in the sample containing both probiotics and inulin on the 28th day at 38.1 (NTU). In general, the synergistic effect of probiotics was more pronounced when used together with both prebiotics in the beverages compared to their individual use. The results suggest that the production of this beverage could serve as a nutritious alternative to lactose-sensitive dairy beverages and contribute to the development of future probiotic food products.

Nutritional and Phytochemical Composition and Associated Health Benefits of Oat (Avena sativa) Grains and Oat-Based Fermented Food Products

Oats (Avena sativa L.) are a popular functional cereal grain due to their numerous health benefits. This review article summarized the information on the chemical composition and phytonutrients of oats grown in different countries. It also reviewed recently developed fermented oat products to highlight their potential for human health. Oats have an interesting nutritional profile that includes high-quality protein, unsaturated fats, soluble fiber, polyphenolic compounds, and micronutrients. Oat grain has a unique protein composition, with globulins serving as the primary storage protein, in contrast to other cereals, where prolamins are the main storage proteins. Oats have the highest fat content of any cereal, with low saturated fatty acids and high essential unsaturated fatty acid content, which can help reduce the risk of cardiovascular diseases. Oats are a good source of soluble dietary fiber, particularly β-glucan, which has outstanding functional properties and is extremely important in human nutrition. β-Glucan has been shown to lower blood cholesterol and glucose absorption in the intestine, thereby preventing diseases such as cardiovascular injury, dyslipidemia, hypertension, inflammatory state, and type 2 diabetes. Oats also contain high concentration of antioxidant compounds. Avenanthramides, which are unique to oats, are powerful antioxidants with high antioxidative activity in humans. Recognizing the nutritional benefits of oats, oat-based fermented food products are gaining popularity as functional foods with high probiotic potential.

Nordic Crops as Alternatives to Soy-An Overview of Nutritional, Sensory, and Functional Properties

Soy (Glycine max) is used in a wide range of products and plays a major role in replacing animal-based products. Since the cultivation of soy is limited by cold climates, this review assessed the nutritional, sensory, and functional properties of three alternative cold-tolerant crops (faba bean (Vicia faba), yellow pea (Pisum sativum), and oat (Avena sativa)). Lower protein quality compared with soy and the presence of anti-nutrients are nutritional problems with all three crops, but different methods to adjust for these problems are available. Off-flavors in all pulses, including soy, and in cereals impair the sensory properties of the resulting food products, and few mitigation methods are successful. The functional properties of faba bean, pea, and oat are comparable to those of soy, which makes them usable for 3D printing, gelation, emulsification, and extrusion. Enzymatic treatment, fermentation, and fibrillation can be applied to improve the nutritional value, sensory attributes, and functional properties of all the three crops assessed, making them suitable for replacing soy in a broad range of products, although more research is needed on all attributes.

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.

Nutritional Facts and Health/Nutrition Claims of Commercial Plant-Based Infant Foods: Where Do We Stand?

One of the current drivers of the infant food market is the rising demand for vegan products, and thus accurate knowledge of their nutritional composition is required to guide parents and health professionals. Thus, this study aimed to assess the nutritional composition of commercial plant-based infant foods, in addition to analyzing their health/nutrition claims. A selection of infant products launched in the global market (2017–2021) were classified into eight types and each type was divided into vegan and vegetarian products. Based on the ingredients list, cereals, seeds, pseudocereals and/or pulses were the most used ingredients in the retrieved products. The nutritional composition of six out eight types varied significantly among vegan and vegetarian products. When protein, calcium and iron contents differed significantly, vegan products had the highest protein content in all categories, compared to those that were vegetarian. When significant differences were found in sugar content, vegan products have lower amounts in all categories, compared to vegetarian products. Health and nutrition claims were found mostly used in vegetarian products. Strategies to reduce added sodium and sugar, and saturated fatty acids is required to ensure a healthy diet for infants. This study also implies the importance of a complete labelling of infants’ foods, especially vegan products to help parents making a reasonable choice.

Dietary-Nutraceutical Properties of Oat Protein and Peptides

Oats are considered the healthiest grain due to their high content of phytochemicals, dietary fibers, and protein. In recent years, oat protein and peptides have gained popularity as possible therapeutic or nutraceutical candidates. Generally, oat peptides with bioactive properties can be obtained by the enzymatic hydrolysis of proteins and are known to have a variety of regulatory functions. This review article focused on the nutraceutical worth of oat proteins and peptides and also describes the application of oat protein as a functional ingredient. Outcomes of this study indicated that oat protein and peptides present various therapeutical properties, including antidiabetic, antioxidant, antihypoxic, antihypertensive, antithrombotic, antifatigue, immunomodulatory, and hypocholestrolaemic. However, most of the conducted studies are limited to in vitro conditions and less data is available on assessing the effectiveness of the oat peptides in vivo. Future efforts should be directed at performing systematic animal studies; in addition, clinical trials also need to be conducted to fully support the development of functional food products, nutraceutical, and therapeutical applications.

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.

Identification and Characterization of Dipeptidyl Peptidase-IV Inhibitory Peptides from Oat Proteins

In this study, flavourzyme, papain, neutrase, and alcalase, as well as gastrointestinal digestion simulated with pepsin and pancreatin, were used to hydrolyze oat protein, and the dipeptidyl peptidase-IV (DPP-IV) inhibitory activities of the oat protein hydrolysates were investigated. The results indicated that the oat protein hydrolysate by neutrase showed the most potent DPP-IV inhibitory property with an IC50 value of 2.55 ± 0.38 mg/mL. Using UPLC-MS/MS, ten new DPP-IV inhibitory peptides were identified from the oat protein hydrolysate by neutrase. Among these peptides, IPQHY, VPQHY, VAVVPF, and VPLGGF exhibited the strongest DPP-IV inhibitory activity with IC50 values below 50 μM, and all of them acted as mixed-type inhibitors. Molecular docking indicated that the above four oat-derived peptides were predicted to form hydrogen bonds, attractive charge, and hydrophobic interactions with the residues of the active site of DPP-IV. Therefore, our results suggest that oat is an excellent protein source for food-derived DPP-IV inhibitory peptides and it has the prospect of becoming a dietary supplement for T2DM.

Nutritional and Therapeutic Potential of Sesame Seeds

The major issue of the current era is an unbalanced and poor diet like unhealthy fast foods, the main cause of various diseases. Most nutraceutical and pharma industries formulating the medicines from artificial sources are expensive and have several side effects. However, scientists are making efforts to find out the natural sources of medicines for the betterment of human health and treatment of diseases. Simultaneously, the worldwide preferences have shifted from artificial to natural resources and unconventional crops (i.e., oilseeds as protein source) and foods are becoming part of regular diet in most of the community, nutraceutical, and pharma industries. Sesame (SesamumindicumL.) is one of the unconventional crops providing multiple benefits due to its special bioactive components, such as sesamin, sesaminol, and gamma-tocopherol, and fatty acids composition like unsaturated fatty acids (i.e., oleic acid, linoleic acid, stearidonic acid, palmitoleic acid, and traces of linolenic acid). Sesame seed oil supplementation not only improves the quality of snack frying oils but also plays a key role in the formation of good quality healthy snack foods. Moreover, its seeds and oil play imperative role in the formulation of medicines utilized for different ailments. The current review highlights the importance and utilization of sesame seed and oil in pharmaceuticals, nutraceuticals, and food (especially snacks) industries.

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.

Functionality of oat fiber concentrate and faba bean protein concentrate in plant-based substitutes for minced meat

Oat has been recognized for its health-promoting fiber, β-glucan, while protein-rich faba bean has remained underutilized in Nordic countries despite its good nutritional quality. This research investigated the functionality of oat fiber concentrate and faba bean protein concentrate in plant-based substitutes for minced meat (SMs). The resulting product aimed at mimicking the mechanical and physicochemical characteristics of beef minced meat (BM) and its applications (i.e., fried and burger patty). In this regard, the mechanical properties (e.g., chewiness, Young's modulus) of original/fried SMs were comparable to or higher than those of original/fried BM. SM patties (45% SMs) were structurally weaker than beef burger patties (100% BM). The rheological analysis showed that the presence of oat fiber concentrate increased the gel-like properties of the blend, which correlated with the overall strength of original SMs (e.g., Young's modulus). The results suggested that SMs could be used as BM for the preparation of vegetarian meat-like products.

•

SMs containing up to 36% dietary fiber—the half being β-glucan—were obtained.

•

Oat-fiber- and faba-bean-protein-concentrate were successfully combined into SMs.

•

SMs were mechanically comparable to beef minced meat.

•

Patties containing SMs were softer than beef patties.

•

Oat fiber concentrate increased the gel-like properties of the blend.

Composition of the Protein Ingredients from Insoluble Oat Byproducts Treated with Food-Grade Enzymes, Such as Amylase, Cellulose/Xylanase, and Protease

The manufacture of plant-based drinks has the drawback of a huge production of underexploited press cakes. In particular, the oat press cake is mainly used in feed formulation, whereas added-value applications in human nutrition are scarce. Considering that enzymatic treatments may be useful to improve the nutritional quality of these insoluble byproducts, this study aimed to evaluate whether the treatment with some food-grade enzymes, such as amylase, cellulase/xylanase, protease, and their combination, may be useful to achieve this goal. Proteomic and peptidomic studies showed that the enzymatic treatments improved the protein extraction yields and induced a release of low molecular weight (LMW) peptides that were demonstrated to provide a useful antioxidant activity. In the treated oat press cake proteins, the concentration of the bound phenolic compounds was decreased, with the exception of caffeic acid, which was increased, and avenanthramides, which remained unchanged. Finally, the enzymatic treatment decreased the concentration of phytic acid. All these results indicate that the enzymatic treatments may be useful to ameliorate the nutritional profile of these protein ingredients, before their inclusion in different food products.

Veggie burgers in the EU market: a nutritional challenge?

Nutritional information of burgers launched in the EU market during 2020 was retrieved from their labels. Products were initially classified into four types: i.e., veggie, red meat-, fish- and poultry-based. Gluten, wheat, and soy were the most declared allergens regardless of the burgers type. Veggie burgers showed levels of energy, fat, and saturate fatty acids (SFA) similar to fish- and poultry-based burgers, but lower than red meat burgers. Compared to conventional burgers, veggie had higher amounts of carbohydrates and sugars and a lower content of proteins, but no difference in salt. Due to the high compositional intra-variability in the veggie burgers, vegetarian and vegan burgers were further analyzed separately. Vegan burgers had higher levels of energy, fat, SFA and protein than vegetarian burgers, but lower carbohydrates and sugars. Once again large differences in the nutritional parameters were observed in both vegan and vegetarian burger categories due to the wide range of ingredients and formulations employed in these types of products. A clear and comprehensive informative labeling is especially needed for vegan and vegetarian burgers to allow the consumer to make a rational decision based on the nutritional facts of these products.