Heat-induced gelation of mixtures of micellar caseins and plant proteins in aqueous solution

High-intensity ultrasound treatment on casein: Pea mixed systems: Effect on gelling properties

This study aimed to investigate the suitability of the application of high-intensity ultrasounds (HIUS) to improve the acid induced gelation of mixed protein systems formed by casein micelles (CMs) and pea. The protein suspensions were prepared in different protein ratios CMs: pea (100:0, 80:20, 50:50, 20:80, 0:100) at 8% (w/w) total protein concentration. In the suspensions, the ultrasound treatment produced an increase in solubility, surface hydrophobicity, and a decrease in the samples' viscosity, with more remarkable differences in protein blends in which pea protein was the major component. However, the replacement of 20% of CMs for pea proteins highly affected the gel elasticity. Hence, the creation of smaller and more hydrophobic building blocks before acidification due to the HIUS treatment increased the elasticity of the gels up to 10 times. Therefore, high-intensity ultrasounds are a suitable green technique to increase the gelling properties of CMs: pea systems.

Combination of Milk and Plant Proteins to Develop Novel Food Systems: What Are the Limits?

In the context of a diet transition from animal protein to plant protein, both for sustainable and healthy scopes, innovative plant-based foods are being developing. A combination with milk proteins has been proposed as a strategy to overcome the scarce functional and sensorial properties of plant proteins. Based on this mixture were designed several colloidal systems such as suspensions, gels, emulsions, and foams which can be found in many food products. This review aims to give profound scientific insights on the challenges and opportunities of developing such binary systems which could soon open a new market category in the food industry. The recent trends in the formulation of each colloidal system, as well as their limits and advantages are here considered. Lastly, new approaches to improve the coexistence of both milk and plant proteins and how they affect the sensorial profile of food products are discussed.

An updated review on the stability of anthocyanins regarding the interaction with food proteins and polysaccharides

The health benefits of anthocyanins are compromised by their chemical instability and susceptibility to external stress. Researchers found that the interaction between anthocyanins and macromolecular components such as proteins and polysaccharides substantially determines the stability of anthocyanins during food processing and storage. The topic thus has attracted much attention in recent years. This review underlines the new insights gained in our current study of physical and chemical properties and functional properties in complex food systems. It examines the interaction between anthocyanins and food proteins or polysaccharides by focusing on the "structure-stability" relationship. Furthermore, multispectral and molecular computing simulations are used as the chief instruments to explore the interaction's mechanism. During processing and storage, the stability of anthocyanins is generally influenced by the adverse characteristics of food and beverage, including temperature, light, oxygen, enzymes, pH. While the action modes and types between protein/polysaccharide and anthocyanins mainly depend on their structures, the noncovalent interaction between them is the key intermolecular force that increases the stability of anthocyanins. Our goal is to provide the latest understanding of the stability of anthocyanins under food processing conditions and further improve their utilization in food industries. Practical Application: This review provides support for the steady-state protection of active substances.

Effects of proteins on emulsion stability: The role of proteins at the oil-water interface

To obtain a stable protein-added emulsion system, researchers have focused on the design of the oil-water interface. This review discussed the updated details of protein adsorption behavior at the oil-water interface. We evaluated methods of monitoring interfacial proteins as well as their strengths and limitations. Based on the effects of structure on protein adsorption, we summarized the contribution of pre-changing methods to adsorption. In addition, the interaction of proteins and other surface-active molecules at the interface had been emphasized. Results showed that protein adsorption is affected by conformation, oil polarity and aqueous environments. The monitoring of interfacial proteins through spectroscopic properties in actual emulsion systems is an emerging trend. Pre-changing could improve the protein adsorption and the purpose of pre-changing of proteins is similar. In the interaction with other surface-active molecules, co-adsorption is desirable. By co-adsorption, the respective advantages can be exploited to obtain a more stable emulsion system.

Colloidal and Acid Gelling Properties of Mixed Milk and Pea Protein Suspensions

The present study aims to describe colloidal and acid gelling properties of mixed suspensions of pea and milk proteins. Mixed protein suspensions were prepared by adding pea protein isolate to rehydrated skimmed milk (3% w/w protein) to generate four mixed samples at 5, 7, 9, and 11% w/w total protein. Skimmed milk powder was also used to prepare four pure milk samples at the same protein concentrations. The samples were analyzed in regard to their pH, viscosity, color, percentage of sedimentable material, heat and ethanol stabilities, and acid gelling properties. Mixed suspensions were darker and presented higher pH, viscosity, and percentage of sedimentable material than milk samples. Heat and ethanol stabilities were similar for both systems and were reduced as a function of total protein concentration. Small oscillation rheology and induced syneresis data showed that the presence of pea proteins accelerated acid gel formation but weakened the final structure of the gels. In this context, the results found in the present work contributed to a better understanding of mixed dairy/plant protein functionalities and the development of new food products.

Effects of antioxidants, proteins, and their combination on emulsion oxidation

Lipid oxidation largely determines the quality of emulsion systems as well as their final products. Therefore, an increasing number of studies have focused on the control of lipid oxidation, particularly on its mechanism. In this review, we discuss the factors affecting the efficiency of antioxidants in emulsion systems, such as the free radical scavenging ability, specifically emphasizing on the interfacial behavior and the influence of surfactants on the interfacial distribution of antioxidants. To enhance the antioxidant efficiency of antioxidants in emulsion systems, we discussed whether the combination of antioxidants and proteins can improve antioxidant effects. The types, mixing applications, structures, interface behaviors, effects of surfactants on interfacial proteins, and the location of proteins are associated with the antioxidant effects of proteins in emulsion systems. Antioxidants and proteins can be combined in both covalent and non-covalent ways. The fabrication conditions, conjugation methods, interface behaviors, and characterization methods of these two combinations are also discussed. Our review provides useful information to guide better strategies for providing stability and controlling lipid oxidation in emulsions. The main challenges and future trends in controlling lipid oxidation in complex emulsion systems are also discussed.

Exploring the potential of polysaccharides or plant proteins as structuring agents to design cheeses with sensory properties focused toward consumers in East and Southeast Asia: a review

The focus of the global cheese industry on accessing new markets for cheese is currently driving a greater need for innovation in cheese products. Research to date suggests that, for example, East Asian consumers prefer cheeses that have a soft texture, with mild and milky flavors. Strategies for achieving such cheese characteristics are reviewed in this article. For example, incorporation of polysaccharides into cheese results in cheese with higher moisture levels and softer textures; this also results in modification of other properties such as adhesiveness, meltability and flavor release. Hydrated polysaccharides may be considered as filler particles within cheese matrices, and therefore filled gel models with suitable filler particles can be used to establish the effect of filler volume, size and surface properties on the fractural and rheological properties of cheese matrices, thus guiding the use of polysaccharides. Addition of plant proteins such as soy and pea protein can also result in cheeses with softer texture. Furthermore, it has been suggested that heat-induced gelation of soy or pea protein with casein results in a gel structure consisting of two independent protein gels, thus facilitating the design of bespoke structures by adjusting the ratio of the two proteins. Finally, it is proposed that incorporation of ingredients with sensory properties familiar to East and Southeast Asian consumers and with the capacity to achieve bespoke textures offer potential for the development of cheese products for consumers in these markets.

Advancement of food-derived mixed protein systems: Interactions, aggregations, and functional properties

Recently, interests in binary protein systems have been developed considerably ascribed to the sustainability, environment-friendly, rich in nutrition, low cost, and tunable mechanical properties of these systems. However, the molecular coalition is challenged by the complex mechanisms of interaction, aggregation, gelation, and emulsifying of the mixed system in which another protein is introduced. To overcome these fundamental difficulties and better modulate the structural and functional properties of binary systems, efforts have been steered to gain basic information regarding the underlying dynamics, theories, and physicochemical characteristics of mixed systems. Therefore, the present review provides an overview of the current studies on the behaviors of proteins in such systems and highlights shortcomings and future challenges when applied in scientific fields.

Heat induced denaturation, aggregation and gelation of almond proteins in skim and full fat almond milk

The effect of thermal treatment (45-95 °C for 30 min) on the structure of almond milk proteins was assessed, as the unfolding and association of these proteins in response to heat is not well understood. Above 55 °C, protein surface hydrophobicity and particle size increased and alpha helical structure decreased, reducing the stability of skim or full fat milk. Fractal protein clusters were observed at 65-75 °C and weakly flocculated gels with a continuous protein network occurred at 85-95 °C, resulting in gels with high water holding capacity and a strength similar to dairy gels. The presence of almond fat increased gel strength but led to a more heterogenous microstructure, which may be improved by homogenisation. Elasticity could also be increased with protein concentration. This study improves our understanding of the heat stability of almond milk proteins and indicates their potential as a gelling ingredient for vegan and vegetarian products.

Molecular Functionality of Plant Proteins from Low- to High-Solid Systems with Ligand and Co-Solute

In the food industry, proteins are regarded as multifunctional systems whose bioactive hetero-polymeric properties are affected by physicochemical interactions with the surrounding components in formulations. Due to their nutritional value, plant proteins are increasingly considered by the new product developer to provide three-dimensional assemblies of required structure, texture, solubility and interfacial/bulk stability with physical, chemical or enzymatic treatment. This molecular flexibility allows them to form systems for the preservation of fresh food, retention of good nutrition and interaction with a range of microconstituents. While, animal- and milk-based proteins have been widely discussed in the literature, the role of plant proteins in the development of functional foods with enhanced nutritional profile and targeted physiological effects can be further explored. This review aims to look into the molecular functionality of plant proteins in relation to the transport of bioactive ingredients and interaction with other ligands and proteins. In doing so, it will consider preparations from low- to high-solids and the effect of structural transformation via gelation, phase separation and vitrification on protein functionality as a delivery vehicle or heterologous complex. Applications for the design of novel functional foods and nutraceuticals will also be discussed.

Correlation Between the Water Solubility and Secondary Structure of Tilapia-Soybean Protein Co-Precipitates

The secondary structure of a protein has been identified to be a crucial indicator that governs its water solubility. Tilapia protein isolate (TPI), soybean protein isolate (SPI), and tilapia-soybean protein co-precipitates (TSPC_3:1, TSPC_2:1, TSPC_1:1, TSPC_1:2, and TSPC_1:3) were prepared by mixing tilapia meat and soybean meal at different mass ratios. The results demonstrated that the water solubility of TSPCs was significantly greater than that of TPI (p <0.05). The changes in ultraviolet–visible and near-ultraviolet circular dichroism spectra indicated that the local structure of TSPCs was different from that of TPI and SPI. Fourier transform infrared Spectroscopy revealed the co-existence of TPI and SPI structures in TSPCs. The secondary structures of TSPCs were predominantly α-helix and β-sheet. TSPC_1:1 was unique compared to the other TSPCs. In addition, there was a good correlation between the water solubility and secondary structure of TSPCs, in which the correlation coefficients of α-helix and β-sheet were −0.964 (p <0.01) and 0.743, respectively. TSPCs displayed lower α-helix contents and higher β-sheet contents compared to TPI, which resulted in a significant increase in their water solubility. Our findings could provide insight into the structure–function relationship of food proteins, thus creating more opportunities to develop innovative applications for mixed proteins.

Gelation of food protein-protein mixtures

Gelation of proteins is one of the principal means to give desirable texture to food products. Gelation of individual proteins in aqueous solution has been investigated intensively in the past, but in most food products the system contains mixtures of different types of proteins. Therefore one needs to consider interaction between different proteins both before and during gelation. Most food proteins can be classified as globular proteins, but casein and gelatin are also important food proteins. In this review the focus is on gelation induced by heating or cooling, which is the most commonly used method. After briefly discussing general features of protein aggregation and gelation, the literature on gelation of mixtures of different types of globular proteins is reviewed as well as that of mixtures of globular proteins with gelatin or with casein. The effect on the gel stiffness and the microstructure of the gelled mixtures will be discussed in terms of different scenarios that can be envisaged: independent aggregation and gelation, co-aggregation and phase separation.