Characteristics of Soy Protein Prepared Using an Aqueous Ethanol Washing Process

Impact of Supercritical CO2 Treatment on Lupin Flour and Lupin Protein Isolates

Global population growth is putting pressure on the food supply, necessitating the exploration of new, alternative, and sustainable protein sources. Lupin, an underutilized legume in human nutrition, has the potential to play a significant role in addressing this challenge. However, its incorporation into the human diet requires thorough investigation, including exploring and optimizing functionalization processes to maximize its potential. This study aimed to optimize the parameters (pressure, time, and CO2 flow) for extracting anti-technological factors (ATFs) from lupin using supercritical CO2 (SC-CO2) and to evaluate the effects of this extraction on both the flour and the protein isolate derived from it. Optimization revealed that the optimal SC-CO2 conditions were a CO2 flow rate of 4 kg/h at 400 bar for 93 min. Under these conditions, significant changes were observed in the flour composition, including a reduction in oil, polyphenols, and moisture content, along with an increase in ash content. Improved color parameters were also noted. These variations were attributed to the removal of oil and phenolic compounds during processing. Furthermore, this research demonstrated that SC-CO2 treatment improved lupin protein isolate (LPI) purity (93.81 ± 0.31% vs. 87.42 ± 0.48%), significantly reduced oil content (8.31 ± 0.09% vs. 14.31 ± 0.32%), and enhanced color parameters. The SC-CO2 procedure also resulted in a higher protein extraction yield (56.95 ± 0.45% vs. 53.29 ± 2.37%). However, the total extraction yield (g LPI/100 g of flour) was not affected by SC-CO2 treatment, remaining at 24.30 ± 0.97% for the control sample and 24.21 ± 0.26% for the treated sample. The extracted oil (2.71 ± 0.11 g/100 g of flour), a co-product of the SC-CO2 step, exhibited a fatty acid profile characterized by high levels of unsaturated fatty acids (62.8 ± 0.74 g/100 g oil), oleic acid (27.76 ± 0.77 g/100 g oil), linoleic acid (25.98 ± 0.73 g/100 g oil), and α-linolenic acid (5.32 ± 0.16 g/100 g oil), as well as a balanced ratio of essential fatty acids (n-6/n-3 = 4.89). The treatment had minimal to no effect on amino acid content or chemical score, and the protein was characterized by high amounts of essential amino acids (334 ± 3.12 and 328 ± 1.05 mg/g protein in LPI-control and LPI-SF, respectively). These findings demonstrate that both the LPI and the oil extracted using SC-CO2 possess high nutritional quality and are suitable for human food applications.

Sustainable protein concentrate from Cannabis sativa L. seeds: Green chemistry and new functional concentrates for the alternative protein industry

This research focused on developing a hemp protein concentrate through a potential sustainable method, with nutritional and industrial value for the emerging alternative protein industry. By response surface methodology, the optimal processing conditions (100% ethanol, 50°C, and 10% w/v solid-to-solvents ratio) resulted in a hemp protein concentrate with 68.61% ± 1.71% protein. The process had a protein yield value of 94.11% ± 4.45%, which aligns with current sustainable food processing trends and is an excellent value compared to traditional methods for hemp seeds. The concentrate met nutritional quality criteria for most examined parameters and showed positive results regarding essential amino acids absorption through in vitro digestion compared to nonessential amino acids. Furthermore, its techno-functional properties, particularly oil-holding capacity, emulsification properties, and gelling qualities achieved commercial standards. This research validates the potential for producing new protein concentrates from dehulled hemp seeds through an innovative green chemistry-based method. PRACTICAL APPLICATION: The research presents a method based on green chemistry for the obtention of hemp protein concentrate from hemp seeds. Hemp seeds are not considered a "novel food" according to the European Commission. Hemp protein concentrate had 95% protein yield and similar or better functional properties compared to commercial proteins. Thus, hemp protein is an important product for food industry applications.

Use of supercritical CO2 to improve the quality of lupin protein isolate

Lupins are an excellent source of protein which can be used to obtain protein isolates with potential use in the food industry. Some studies use supercritical CO2 (SC-CO2) to defat legume flours, but no study analyzes the effect of applying this technology directly to the protein isolate. This article has proposed the use of SC-CO2 to improve lupin protein isolate (LPI) quality. SC-CO2 increased the LPI purity while reducing oil and other antitechnological factors (saponins and polyphenols). The treatment significantly improved the LPI color due to the elimination of the lipid fraction and lipophilic pigments (carotenoids). No changes in amino acid contents or chemical score were observed due to the SC-CO2. Finally, the treatment improved or did not affect the main LPI technofunctional properties. Therefore, SC-CO2 is a promising technique to enhance the quality of protein isolates, without affecting or improving their functional properties.

Advancements in plant based meat analogs enhancing sensory and nutritional attributes

The burgeoning demand for plant-based meat analogs (PBMAs) stems from environmental, health, and ethical concerns, yet replicating the sensory attributes of animal meat remains challenging. This comprehensive review explores recent innovations in PBMA ingredients and methodologies, emphasizing advancements in texture, flavor, and nutritional profiles. It chronicles the transition from soy-based first-generation products to more diversified second- and third-generation PBMAs, showcasing the utilization of various plant proteins and advanced processing techniques to enrich sensory experiences. The review underscores the crucial role of proteins, polysaccharides, and fats in mimicking meat's texture and flavor and emphasizes research on new plant-based sources to improve product quality. Addressing challenges like production costs, taste, texture, and nutritional adequacy is vital for enhancing consumer acceptance and fostering a more sustainable food system.

Saline as solvent and ethanol-based purification process for the extraction of proteins and isoflavones from wet okara

Okara, the solid byproduct of water-soluble soybean extract production, is a potential source of proteins and isoflavones. This study investigated different experimental configurations for extracting these compounds from wet okara, including lipid removal with ethanol at different stages of the recovery process, sequential crosscurrent extraction, and using a saline MgCl2 solution as the solvent. Three washes with a 60:40 ethanol:water (w/w) solution after isoelectric precipitation significantly increased protein content by reducing lipid content (60 %). The crosscurrent approach using 0.05 M MgCl2 yielded okara proteinaceous material with 248 µg/g daidzein and 236 µg/g genistein, along with a 3 % increase in protein content, attributed to enhanced extraction of 7S globulins. These configurations notably affected the functional properties of the protein materials. Overall, this research provides detailed insights into the composition and properties of proteins extracted from wet okara, facilitating their specialized application in food products.

Effect of heat treatment on the release of off-flavor compounds in soy protein isolate

The effects of different heat treatment conditions (65℃ for 30 min, 75℃ for 15 min, and 95℃ for 2, 15 and 30 min) on the evolution of off-flavor compounds in soy protein isolate (SPI) were investigated in terms of lipid oxidation, Maillard reaction and protein structural characteristics. Higher off-flavor concentrations were observed in control and 65℃ treated SPI due to lipoxygenase-mediated enzymatic lipid oxidation. Protein structure played an important role in the release of off-flavors above 65℃. When heated from 75℃ to 95℃ for 2 min, Maillard reaction occurred, glycinin was completely denatured, the particle size increased and the small molecular weight soluble aggregates were formed, resulting in an increase in the content of partial off-flavors. The off-flavor content decreased with time at 95℃, accompanied by the formation of larger molecular weight soluble aggregates. This finding provides practical implications for the beany removal through the SPI structural regulation.

Effect of ethanol treatment on the structural, techno-functional, and antioxidant properties of edible insect protein obtained from Tenebrio molitor larvae

Edible insect-derived proteins have attracted considerable attention in the food industry owing to their excellent nutritional and bio-functional activities. Herein, ethanol (20, 40, 60, and 80 %)-treated Tenebrio molitor protein (ETMP) was prepared, and its structural, techno-functional, and antioxidant properties were assessed. As the ethanol concentration increased, the molecular weight of the ETMP decreased, and α-helix content decreased whereas that of β-sheet increased, affecting the secondary structure. Ethanol treatment also resulted in changes in the techno-functional properties of edible insect proteins. ETMP showed significant 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical-scavenging activity (p < 0.05), and its antioxidant activity effectively increased the viability of Vero cells damaged by oxidative stress; 20 % ethanol treatment induced the highest antioxidant activity. In conclusion, our results suggest that appropriate ethanol treatment (20 %) increases the antioxidant activity of edible insect proteins, suggesting their potential in food as an alternative protein resource and functional food with excellent antioxidant activity.

Varying precipitation conditions allow directing the composition and physical properties of soy protein concentrates

Soy protein concentrates (SPCs) are common food ingredients. They typically contain 65% (w/w) protein and ∼30% (w/w) carbohydrate. SPCs can be obtained with various protein precipitation conditions. A systematic study of the impact of these different protein precipitation protocols on the SPC protein composition and physical properties is still lacking. Here, SPCs were prepared via three different protocols, that is, isoelectric (pH 3.5-5.5), aqueous ethanol (50%-70% [v/v]), and Ca2+ ion (5-50 mM) based precipitations, and analyzed for (protein) composition, protein thermal properties, dispersibility, and water-holding capacity. SPCs precipitated at pH 5.5 or by adding 15 mM Ca2+ ions had a lower 7S/11S globulin ratio (∼0.40) than that (∼0.50) of all other SPC samples. Protein in SPCs obtained by isoelectric precipitation denatured at a significantly higher temperature than those in ethanol- or Ca2+ -precipitated SPCs. Precipitation with 50%-60% (v/v) ethanol resulted in pronounced denaturation of 2S albumin and 7S globulin fractions in SPCs. Additionally, increasing the precipitation pH from 3.5 to 5.5 and increasing the Ca2+ ion concentration from 15 to 50 mM caused a strong decrease of both the dispersibility of the protein in SPC and its water-holding capacity at pH 7.0. In conclusion, this study demonstrates that the SPC production process can be directed to obtain ingredients with versatile protein physicochemical properties toward potential food applications. PRACTICAL APPLICATION: This study demonstrates that applying different protein precipitation protocols allows obtaining SPCs that vary widely in (protein) composition and physical properties (such as protein dispersibility and water-holding capacity). These varying traits can greatly influence the suitability of SPCs as functional ingredients for specific applications, such as the production of food foams, emulsions, gels, and plant-based meat alternatives. The generated knowledge may allow targeted production of SPCs for specific applications.

The Interactions of Soy Protein and Wheat Gluten for the Development of Meat-like Fibrous Structure

Consumers who are environmentally and health conscious are increasingly looking for plant-based alternatives to replace animal-based products in their daily diets. Among these alternatives, there is a growing demand for meat analogues that closely resemble the taste and texture of meat. As a result, significant efforts have been dedicated to developing meat analogues with a desirable meat-like structure. Currently, soy protein and wheat gluten are the main ingredients used for producing these meat analogues due to their availability and unique functionalities. This study observed that high moisture extrusion at moisture levels of 50-80% has become a common approach for creating fibrous structures, with soy protein and wheat gluten being considered incompatible proteins. After the structuring process, they form two-phase filled gels, with wheat gluten acting as the continuous phase and soy protein serving as a filler material. Moreover, the formation of soy protein and wheat gluten networks relies on a combination of covalent and non-covalent interaction bonds, including hydrogen bonds that stabilize the protein networks, hydrophobic interactions governing protein chain associations during thermo-mechanical processes, and disulfide bonds that potentially contribute to fibrous structure formation. This review provides case studies and examples that demonstrate how specific processing conditions can improve the overall structure, aiming to serve as a valuable reference for further research and the advancement of fibrous structures.

Partial characterization of canola (Brassica napus L.) protein isolates as affected by extraction and purification methods

Canola (Brassica napus L.) meal represents a prominent alternative plant-based source for protein isolation. This work aimed to investigate the combined effect of extraction and purification methods for the production of canola protein isolates (CPIs). CPIs were characterized in terms of process yield, protein recovery, basic composition, amino acid profile, in vitro protein digestibility, techno-functional properties, structural properties, and molecular features. The results showed that the Alk-Uf method enhanced yield (16.23 %) and protein recovery (34.88 %). Meanwhile, the Et-Alk-Uf method exhibited the highest crude protein (89.71 %) and free amino nitrogen (4.34 mg g protein-1) contents. Furthermore, protein digestibility (95.5 %) and protein digestibility corrected amino acid score (1.0) were improved using the Et-Alk-Ac method. Conversely, the amino acid composition, secondary structure, and electrophoretic profiles were generally similar for all CPIs. The Alk-Uf and Et-Alk-Uf methods produced isolates with the highest water solubility (∼39.18 %), water absorption capacity (∼3.86 g water g protein-1), oil absorption capacity (∼2.77 g oil g protein-1), and foaming capacity (∼505.26 %). Finally, the foaming stability (93.75 %) and foaming density (34.38 %) were increased when employing the Alk-Ac method. These findings suggest that, in general, the Alk-Uf and Et-Alk-Uf methods can be used to obtain CPIs with high added value for use in food formulations.

Production and functional characteristics of low-sodium high-potassium soy protein for the development of healthy soy-based foods

The plant-based products that are mainly produced by soy protein isolate (SPI) present significantly higher sodium (Na) content than the corresponding animal-based products. Accordingly, the production of low-sodium soy protein ingredients becomes a challenging task. For this purpose, alternative soy fractionation processes were investigated, and the use of KOH as the replacement for NaOH has been established to produce soy protein fractions (SPFs). The obtained MF-K contained 0.2 mg sodium and 24 mg potassium per 100 g of fraction, which was 3 % of the sodium content in the SPI, and the potassium content was over 10 times higher than SPI. Besides, using KOH increased the protein content of SPFs by almost 7 %, as well as their water holding capacity (WHC) and thermal stability; however, the yields of SPFs were dropped by around 4-8 % while the protein solubility of SPFs was reduced companied with the application of KOH. The fractionation processes mainly affected the protein composition, powder morphology, and viscosity of SPFs, while the sodium and potassium content showed limited impacts on the variations. Overall, the application of KOH during different fractionation procedures provided the possibility to produce low-sodium high‑potassium soy protein ingredients for the development of healthy soy-based foods.

Initial Formulation of Novel Peanut Butter-like Products from Glandless Cottonseed

Glandless (Gl) cottonseed is a unique cotton variety with only a trace content of toxic gossypol present. This new cottonseed raises the potential of its enhanced utilization as an agro-food for human consumption. In this work, Gl cottonseed kernels were used with additional cottonseed oil to produce novel peanut butter-like products. Kernels roasted at two temperatures (140 or 150 °C) for a given time (15 or 30 min) were first ground with different ratios of cottonseed oil and two other ingredients (i.e., salt and sugar) with a food blender, and then passed through a meat grinder with a 4-mm-hole grinding plate. Per the preliminary result, the butter-like products with Gl kernels roasted at 150 °C were subject to further structural and textural evaluation. The color of the two butter-like products was comparable to a commercial peanut butter, but the formers’ textural properties were significantly different (p ≤ 0.05) from the latter. Morphologic examination by Scanning Electron Microscopy (SEM) and cryo-SEM revealed that the butter product with a longer (30 min) roasting time possessed a smoother surface than the products with a shorter (15 min) roasting time. Oil stability test showed no substantial oil separation (<3%) from the butter products over 7 weeks at ambient temperature (22 °C). This work provides the basic information and parameters for lab cottonseed butter making so that optimization and characterization of cottonseed butter formation can be designed and performed in future research.

Evaluation of a low-resource soy protein production method and its products

Introduction

One key approach to achieve zero hunger in Sub-Saharan Africa (SSA) is to develop sustainable, affordable, and green technologies to process nutritious food products from locally available sources. Soybeans are an inexpensive source of high-quality protein that may help reduce undernutrition, but it is underutilized for human consumption. This research evaluated the feasibility of a low-cost method developed initially at the United States Department of Agriculture to produce soy protein concentrate (SPC) from mechanically pressed soy cake and thus create a more valuable ingredient to improve protein intake in SSA.

Methods

The method was initially tested in the bench scale to assess process parameters. Raw ingredients comprised defatted soy flour (DSF), defatted toasted soy flour (DTSF), low-fat soy flour 1 (LFSF1; 8% oil), and LFSF2 (13% oil). Flours were mixed with water (1:10 w/v) at two temperatures (22 or 60°C) for two durations (30 or 60 min). After centrifugation, supernatants were decanted, and pellets were dried at 60°C for 2.5 h. Larger batches (350 g) of LFSF1 were used to examine the scalability of this method. At this level, protein, oil, crude fiber, ash, and phytic acid contents were measured. Thiobarbituric acid reactive substances (TBARS), hexanal concentration and peroxide value were measured in SPC and oil to evaluate oxidative status. Amino acid profiles, in vitro protein digestibility, and protein digestibility corrected amino acid score (PDCAAS) were determined to assess protein quality.

Results

Bench scale results showed accumulation of protein (1.5-fold higher) and reduction of oxidative markers and phytic acid to almost half their initial values. Similarly, the large-scale production trials showed high batch-to-batch replicability and 1.3-fold protein increase from initial material (48%). The SPC also showed reductions in peroxide value (53%), TBARS (75%), and hexanal (32%) from the starting material. SPC's in vitro protein digestibility was higher than the starting material.

Conclusion

The proposed low-resource method results in an SPC with improved nutritional quality, higher oxidative stability, and lower antinutrient content, which enhances its use in food-to-food fortification for human consumption and is thus amenable to address protein quantity and quality gaps among vulnerable populations in SSA.

Comparison on Protein Bioaccessibility of Soymilk Gels Induced by Glucono-δ-Lactone and Lactic Acid Bacteria

In this study, the protein bioaccessibility of soymilk gels produced by the addition of glu-cono-δ-lactone (GDL) and fermentation with lactic acid bacteria (LAB) was examined using an in vitro gastrointestinal simulated digestion model. The in vitro protein digestibility, soluble protein content, free amino acids contents, degree of hydrolysis, electrophoretic patterns, and peptide content were measured. The results suggested that acid-induced soymilk gel generated by GDL (SG) showed considerably reduced in vitro protein digestibility of 75.33 ± 1.00% compared to the soymilk gel induced by LAB (SL) of 80.57 ± 1.53% (p < 0.05). During the gastric digestion stage, dramatically higher (p < 0.05) soluble protein contents were observed in the SG (4.79−5.05 mg/mL) than that of SL (4.31−4.35 mg/mL). However, during the later intestinal digestion phase, the results were the opposite. At the end of the gastrointestinal digestion phase, the content of small peptides was not significantly different (p > 0.05) between the SL (2.15 ± 0.03 mg/mL) and SG (2.17 ± 0.01 mg/mL), but SL showed higher content of free amino acids (20.637 g/L) than that of SG (19.851 g/L). In general, soymilk gel induced by LAB had a higher protein bioaccessibility than the soymilk gel coagulated by GDL.

Chemical Composition and Thermogravimetric Behaviors of Glanded and Glandless Cottonseed Kernels

Common “glanded” (Gd) cottonseeds contain the toxic compound gossypol that restricts human consumption of the derived products. The “glandless” (Gl) cottonseeds of a new cotton variety, in contrast, show a trace gossypol content, indicating the great potential of cottonseed for agro-food applications. This work comparatively evaluated the chemical composition and thermogravimetric behaviors of the two types of cottonseed kernels. In contrast to the high gossypol content (3.75 g kg⁻¹) observed in Gd kernels, the gossypol level detected in Gl kernels was only 0.06 g kg⁻¹, meeting the FDA’s criteria as human food. While the gossypol gland dots in Gd kernels were visually observed, scanning electron microcopy was not able to distinguish the microstructural difference between ground Gd and Gl samples. Chemical analysis and Fourier transform infrared (FTIR) spectroscopy showed that Gl kernels and Gd kernels had similar chemical components and mineral contents, but the former was slightly higher in protein, starch, and phosphorus contents. Thermogravimetric (TG) processes of both kernels and their residues after hexane and ethanol extraction were based on three stages of drying, de-volatilization, and char formation. TG-FTIR analysis revealed apparent spectral differences between Gd and Gl samples, as well as between raw and extracted cottonseed kernel samples, indicating that some components in Gd kernels were more susceptible to thermal decomposition than Gl kernels. The TG and TG-FTIR observations suggested that the Gl kernels could be heat treated (e.g., frying and roasting) at an optimal temperature of 140–150 °C for food applications. On the other hand, optimal pyrolysis temperatures would be much higher (350–500 °C) for Gd cottonseed and its defatted residues for non-food bio-oil and biochar production. The findings from this research enhance the potential utilization of Gd and Gl cottonseed kernels for food applications.