Plant-Based Protein-Phenolic Interactions: Effect on different matrices and in vitro gastrointestinal digestion

Unveiling the nutritional spectrum: A comprehensive analysis of protein quality and antinutritional factors in three varieties of quinoa (Chenopodium quinoa Wild)

Quinoa (Chenopodium quinoa) is renowned for its high protein content and balanced amino acid profile. Despite promising protein characteristics, plant-based sources usually possess antinutritional factors (ANFs). This study aimed to analyze the nutritional and ANFs composition of three quinoa varieties (Black, Yellow, and Red), and assessed the protein quality. Among these varieties, Black quinoa showed the highest protein content (20.90 g/100 g) and total dietary fiber (TDF) (22.97 g/100 g). In contrast, Red quinoa exhibited the highest concentration of phenolic compounds (338.9 mg/100 g). The predominant ANFs identified included oxalates (ranging from 396.9 to 715.2 mg/100 g), saponins (83.27-96.82 g/100 g), and trypsin inhibitors (0.35-0.46 TUI/100 g). All three varieties showed similar in vitro protein digestibility (IVPD) (> 76.9 %), while Black quinoa exhibited the highest protein quality. In conclusion to ensure reduction of ANFs, processing methods are necessary in order to fully benefit from the high protein and nutritional value of quinoa.

Soy protein-polyphenols conjugates interaction mechanism, characterization, techno-functional and biological properties: An updated review

Soy protein is a promising nutritional source with improved functionality and bioactivities due to conjugation with polyphenols (PP)-the conjugates between soy protein and PP held by covalent and noncovalent bonds. Different approaches, including thermodynamics, spectroscopy, and molecular docking simulations, can demonstrate the outcomes and mechanism of these conjugates. The soy protein, PP structure, matrix properties (temperature, pH), and interaction mechanism alter the ζ-potential, secondary structure, thermal stability, and surface hydrophobicity of proteins and also improve the techno-functional properties such as gelling ability, solubility, emulsifying, and foaming properties. Soy protein-PP conjugates also reveal enhanced in vitro digestibility, anti-allergic, antioxidant, anticancer, anti-inflammatory, and antimicrobial activities. Thus, these conjugates may be employed as edible film additives, antioxidant emulsifiers, hydrogels, and nanoparticles in the food industry. Future research is needed to specify the structure-function associations of soy protein-PP conjugates that may affect their functionality and application in the food industry.

The composition, extraction, functional property, quality, and health benefits of coconut protein: A review

Coconut is widely appreciated for its distinctive flavor and is commonly utilized in the production of a variety of goods. Coconut protein, a by-product derived from coconut oil and coconut milk cake, is frequently underutilized or discarded. This study provides a comprehensive overview of the distribution and composition of coconut protein. Analyses reveal that coconut protein, specifically 11S globulin and 7S globulin, is predominantly found in coconut flesh. Furthermore, various extraction techniques for coconut protein, such as chemical, enzymatic, and physical methods, are discussed. The alkali dissolution and acid precipitation methods are widely utilized for extracting coconut protein, with the potential for enhancement through the incorporation of physical methods such as ultrasound. The evaluation of functional properties, quality, and health benefits of coconut protein is essential, given the limitations imposed by its solubility. Modification may be necessary to optimize its functional properties. Coconut presents a promising source of food protein, characterized by balanced amino acid composition, high digestibility, and low allergenic potential. In conclusion, this study provides a comprehensive overview of the extraction methods, functional properties, quality, and nutritional benefits of coconut protein, offering insights for potential future research directions in the field. Additionally, the information presented may serve as a valuable reference for incorporating coconut protein into plant-based food products.

Differential binding of gallic acid and epigallocatechin gallate to whey protein affects the interfacial adsorption and gastric digestion of O/W emulsion

Whey protein isolate (WPI) was reacted with 20, 120, and 240 μmol/g gallic acid (GA) or epigallocatechin gallate (EGCG) at 21 °C. Equilibrium dialysis testing indicated a stronger binding capacity of whey proteins with EGCG compared to GA. Both phenolics, especially EGCG, tended to reduce the adsorption of WPI at the oil-water interface and decreased the elasticity modulus (Ed) of the interfacial film. Yet, binding with 20 μmol/g of EGCG and GA (less so) resulted in significantly improved emulsifying activity of WPI, but the emulsion stability was decreased at all phenolic concentrations (except at 240 μmol/g). There was an overall improvement of pepsinolysis of both α-lactalbumin and β-lactoglobulin. In comparison with GA, EGCG yielded more pronounced effects on WPI interfacial adsorption, dilatational rheology, and peptic digestion.

An Overview of Interactions between Goat Milk Casein and Other Food Components: Polysaccharides, Polyphenols, and Metal Ions

Casein is among the most abundant proteins in milk and has high nutritional value. Casein's interactions with polysaccharides, polyphenols, and metal ions are important for regulating the functional properties and textural quality of dairy foods. To improve the functional properties of casein-based foods, a deep understanding of the interaction mechanisms and the influencing factors between casein and other food components is required. This review started by elucidating the interaction mechanism of casein with polysaccharides, polyphenols, and metal ions. Thermodynamic incompatibility and attraction are the fundamental factors in determining the interaction types between casein and polysaccharides, which leads to different phase behaviors and microstructural types in casein-based foods. Additionally, the interaction of casein with polyphenols primarily occurs through non-covalent (hydrogen bonding, hydrophobic interactions, van der Waals forces, and ionic bonding) or covalent interaction (primarily based on the oxidation of proteins or polyphenols by enzymatic or non-enzymatic (alkaline or free radical grafting) approaches). Moreover, the selectivity of casein to specific metal ions is also introduced. Factors affecting the binding of casein to the above three components, such as temperature, pH, the mixing ratio, and the fine structure of these components, are also summarized to provide a good foundation for casein-based food applications.

Decoding the Duality of Antinutrients: Assessing the Impact of Protein Extraction Methods on Plant-Based Protein Sources

This review aims to provide an updated overview of the effects of protein extraction/recovery on antinutritional factors (ANFs) in plant protein ingredients, such as protein-rich fractions, protein concentrates, and isolates. ANFs mainly include lectins, trypsin inhibitors, phytic acid, phenolic compounds, oxalates, saponins, tannins, and cyanogenic glycosides. The current technologies used to recover proteins (e.g., wet extraction, dry fractionation) and novel technologies (e.g., membrane processing) are included in this review. The mechanisms involved during protein extraction/recovery that may enhance or decrease the ANF content in plant protein ingredients are discussed. However, studies on the effects of protein extraction/recovery on specific ANFs are still scarce, especially for novel technologies such as ultrasound- and microwave-assisted extraction and membrane processing. Although the negative effects of ANFs on protein digestibility and the overall absorption of plant proteins and other nutrients are a health concern, it is also important to highlight the potential positive effects of ANFs. This is particularly relevant given the rise of novel protein ingredients in the market and the potential presence or absence of these factors and their effects on consumers' health.

Soy protein isolate-catechin complexes conjugated by pre-heating treatment for enhancing emulsifying properties: Molecular structures and binding mechanisms

This study aimed to investigate the impact of different pre-heating temperatures (ranging from 40 °C to 80 °C) on the interactions between soy protein isolate (SPI) and catechin to effectively control catechin encapsulation efficiency and optimize the emulsifying properties of soy protein isolate. Results showed that optimal heat treatment at 70 °C improved catechin encapsulation efficiency up to 93.71 ± 0.14 %, along with the highest solubility, enhanced emulsification activity index and improved thermal stability of the protein. Multiple spectroscopic techniques revealed that increasing pretreatment temperature (from 40 °C to 70 °C) altered the secondary structures of SPI, resulting in a more stable unfolded structure for the composite system with a significant increase in α-helical structures and a decrease in random coil and β-sheet structures. Moreover, optimal heat treatment also leads to an augmentation of free sulfhydryl groups within complex as well as exposure of more internal chromophore amino acids on molecular surface. Size-exclusion high-performance liquid chromatography and SDS-PAGE analysis indicated that the band intensity of newly formed high-molecular-weight soluble macromolecules (>180 kDa) increased as the pre-heating temperature rose. Furthermore, fluorescence spectroscopy and molecular docking analysis suggest that hydrophobic and covalent interactions were involved in complex formation, which intensified with increasing temperature.

Egg White Protein-Proanthocyanin Complexes Stabilized Emulsions: Investigation of Physical Stability, Digestion Kinetics, and Free Fatty Acid Release Dynamics

Egg white proteins pose notable limitations in emulsion applications due to their inadequate wettability and interfacial instability. Polyphenol-driven alterations in proteins serve as an effective strategy for optimizing their properties. Herein, covalent and non-covalent complexes of egg white proteins-proanthocyanins were synthesized. The analysis of structural alterations, amino acid side chains and wettability was performed. The superior wettability (80.00° ± 2.23°) and rigid structure (2.95 GPa) of covalent complexes established favorable conditions for their utilization in emulsions. Furthermore, stability evaluation, digestion kinetics, free fatty acid (FFA) release kinetics, and correlation analysis were explored to unravel the impact of covalent and non-covalent modification on emulsion stability, dynamic digestion process, and interlinkages. Emulsion stabilized by covalent complex exhibited exceptional stabilization properties, and FFA release kinetics followed both first-order and Korsmeyer-Peppas models. This study offers valuable insights into the application of complexes of proteins-polyphenols in emulsion systems and introduces an innovative approach for analyzing the dynamics of the emulsion digestion process.

Plant-based proteins: advanced extraction technologies, interactions, physicochemical and functional properties, food and related applications, and health benefits

Even though plant proteins are more plentiful and affordable than animal proteins in comparison, direct usage of plant-based proteins (PBPs) is still limited because PBPs are fed to animals as feed to produce animal-based proteins. Thus, this work has comprehensively reviewed the effects of various factors such as pH, temperature, pressure, and ionic strength on PBP properties, as well as describes the protein interactions, and extraction methods to know the optimal conditions for preparing PBP-based products with high functional properties and health benefits. According to the cited studies in the current work, the environmental factors, particularly pH and ionic strength significantly affected on physicochemical and functional properties of PBPs, especially solubility was 76.0% to 83.9% at pH = 2, while at pH = 5.0 reduced from 5.3% to 9.6%, emulsifying ability was the lowest at pH = 5.8 and the highest at pH 8.0, and foaming capacity was lowest at pH 5.0 and the highest at pH = 7.0. Electrostatic interactions are the main way for protein interactions, which can be used to create protein/polysaccharide complexes for food industrial purposes. The extraction yield of proteins can be reached up to 86-95% with high functional properties using sustainable and efficient routes, including enzymatic, ultrasound-, microwave-, pulsed electric field-, and high-pressure-assisted extraction. Nondairy alternative products, especially yogurt, 3D food printing and meat analogs, synthesis of nanoparticles, and bioplastics and packaging films are the best available PBPs-based products. Moreover, PBPs particularly those that contain pigments and their products showed good bioactivities, especially antioxidants, antidiabetic, and antimicrobial.