Ohmic heating as a new tool for protein scaffold engineering

Abstract

Ohmic heating (OH) is recognised as an emerging processing technology which recently is gaining increasing attention due to its ability to induce and control protein functionality. In this study, OH was used for the first time in the production of scaffolds for tissue engineering. BSA/casein solutions were processed by OH, promoting protein denaturation and aggregation, followed by cold-gelation through the addition of Ca 2+ . The formation of stable scaffolds was mostly dependent on the temperature and treatment time during OH processing. The variations of the electric field (EF) induced changes in the functional properties of both gel forming solutions and final scaffolds (contact angle, swelling, porosity, compressive modulus and degradation rate). The scaffolds' biological performance was evaluated regarding their ability to support the adhesion and proliferation of human fibroblast cells. The production process resulted in a non-cytotoxic material and the changes imposed by the presence of the EF during the scaffolds' production improved cellular proliferation and metabolic activity. Protein functionalization assisted by OH presents a promising new alternative for the production of improved and tuneable protein-based scaffolds for tissue engineering.

Effect of Dietary Protein and Processing on Gut Microbiota—A Systematic Review

“…These changes can induce the aggregation of proteins and affect protein digestibility by compromising the efficacy of digestive enzymes and production and the release of digestive end products [ 125 ]. Similarly, ohmic heating, which applies the Joule effect to produce heat inside the food products through the application of alternating current [ 126 ], affects the structure of proteins and their interactions and the formation of protein aggregates [ 127 ]. The conformational, structural, and microstructural changes induced in the food proteins and matrices during ohmic heating are a result of a combined effect of thermal and non-thermal effects (electrochemical reactions and electrical effects) [ 127 , 128 ].…”

“…Similarly, ohmic heating, which applies the Joule effect to produce heat inside the food products through the application of alternating current [ 126 ], affects the structure of proteins and their interactions and the formation of protein aggregates [ 127 ]. The conformational, structural, and microstructural changes induced in the food proteins and matrices during ohmic heating are a result of a combined effect of thermal and non-thermal effects (electrochemical reactions and electrical effects) [ 127 , 128 ]. Ohmic heating has been reported to increase the digestibility of whey proteins by unfolding their complex structure by disrupting the covalent bonds and, thereby, increasing the availability of hydrolytic sites [ 129 ].…”

Emergent Proteins-Based Structures—Prospects towards Sustainable Nutrition and Functionality

“…Scaffolds for tissue engineering can be produced using BSA (4.19%, w/v) and casein (0.69%, w/v) through the Ca 2+ -induced "cold gelation" procedure [93]. A recent study unveiled that a proper optimization of the heating conditions during the scaffolds' production can avoid the use of reducing agents such as ditiotreitol (DTT) [4]. Figure 2 evidence microstructure of BSA/casein scaffold produced under conventional heating and ohmic heating, highlighting the importance of the heating process and presence of an electric field on the obtainment of singular protein networks.…”

“…Another study showed that, independent of the level of protein purification, the extracts from A. platensis can help stabilize emulsions; however, authors also conclude that purification can improve functionality by yielding smaller emulsion droplets and stronger viscoelastic networks at the oil-water interface [103]. Contrary to what happens to common animal-based proteins such as milk, proteins from microalgae biomass can act as emulsions and foams stabilizers in a broad range of pH and ionic strength due to their characteristically low isoelectric point (3)(4) [97].…”

“…These superstructures can be produced at nano-and microscale and used as delivery systems for drugs and bioactive compounds, thus bringing nutritional advantages and targeted health functions. Other emergent area of application is closely related with tissue engineering applications through development of 3D architectures that can support and leverage cellular growth [4]. Paradoxically, diverse human neurodegenerative diseases, such as Alzheimer's, Parkinson's, and transmissible spongiform encephalopathies are intrinsically related with changes in the protein folding that lead to misfolded fibrillar structures, known as the amyloid fibrils [5].…”