Thermal stability and rheological properties of heat-induced gels prepared using edible insect proteins in a model system

Effects of ultrasound-induced structural modifications on the emulsifying properties of Tenebrio molitor proteins

Ultrasonication has emerged as a promising technique for modifying physicochemical properties of proteins, enhancing their functionality in food applications. This study evaluated the effects of ultrasonic treatment on the structural and functional properties of mealworm-derived proteins (MPs) and their potential as emulsifiers. Dynamic light scattering revealed a significant reduction in MP particle size from 3464.3 nm (untreated) to 115.5 nm (30 min sonication), along with increased zeta potential, indicating improved colloidal stability. Sonication enhanced oil-holding capacity and solubility, suggesting improved interfacial adsorption and emulsification. Circular dichroism and FT-IR spectroscopy confirmed structural modifications, including increased α-helix content and enhanced hydrogen bonding interactions. Free sulfhydryl content and surface hydrophobicity analyses indicated ultrasound-induced unfolding, exposing functional groups that contribute to emulsifying properties. Sonicated MPs demonstrated superior emulsion stability under varying temperature, pH, and ionic conditions. Furthermore, digestibility analysis showed improved gastric digestion (72.7 % to 82.8 %) and enhanced lipid digestion in the small intestine (36.2 % to 47.9 %), suggesting greater bioavailability. These physicochemical modifications highlight the feasibility of using sonicated MP as natural emulsifiers with enhanced functionality. This study underscores their potential in food formulations, particularly for nutritionally fortified emulsions, contributing to sustainable and functional food ingredient development.

Current challenges of alternative proteins as future foods

Global demand for food is expected to nearly double by 2050. Alternative proteins (AP) have been proposed as a sustainable solution to provide food security as natural resources become more depleted. However, the growth and consumer intake of AP remains limited. This review aims to better understand the challenges and environmental impacts of four main AP categories: plant-based, insect-based, microbe-derived, and cultured meat and seafood. The environmental benefits of plant-based and insect-based proteins have been documented but the impacts of microbe-derived proteins and cultured meat have not been fully assessed. The development of alternative products with nutritional and sensory profiles similar to their conventional counterparts remains highly challenging. Furthermore, incomplete safety assessments and a lack of clear regulatory guidelines confuse the food industry and hamper progress. Much still needs to be done to fully support AP utilization within the context of supporting the drive to make the global food system sustainable.

Effect of gamma-ray and electron-beam irradiation on the structural changes and functional properties of edible insect proteins from Protaetia brevitarsis larvae

Edible insects are regarded as future food sources to replace traditional livestock proteins. However, insect proteins have poor processing properties owing to various structural limitations. We investigated the structure of Protaetia brevitarsis larvae proteins modified by irradiation, and analyzed their resulting processing abilities. Following irradiation with gamma rays and electron beams, the ratio of parallel β-sheets to β-turns changed significantly, and changes in the tertiary protein structures were also confirmed. The polydispersity indices of the proteins remained relatively constant following irradiation, although the zeta potential and mean diameter changed. Furthermore, the pH, protein solubility, surface hydrophobicity, foaming capacity, and emulsion stability were higher than those of the control, whereas the viscosity and foaming stability were lower. Thus, gamma ray and electron beam irradiation clearly lead to changes in the structures of edible insect proteins and improves their processing properties, promoting the industrial utilization of such proteins in the food industry.

Effects of protein aggregation induced by NaCl and temperature on gelation of silkworm (Antheraea pernyi) pupa raw powder

Edible insects have great potential for producing protein-rich ingredients. This study aimed to investigate the effects of protein aggregation induced by NaCl (0-1 M) and temperature (65-95 °C) on gelation of Antheraea pernyi (A. pernyi) pupa raw powder. No thermal aggregates were observed at low temperature (65 °C), on the basis of there being no significant enhancement in turbidity and particle size (P > 0.05), regardless of NaCl concentrations. At elevated temperatures (75-95 °C), protein solutions exhibited significantly higher turbidity and particle size (P < 0.05), accompanied by an initial rise in surface hydrophobicity followed by a decline, alongside declining sulfhydryl. This marks the beginning of massive thermal aggregation driven by molecular forces. In addition, covalent (disulfide bonds) and non-covalent (hydrogen bonding, electrostatic interactions, and hydrophobicity) forces were influenced by NaCl, leading to variability in the protein aggregation and gelation. Correlation analysis indicates that the higher protein aggregation induced by ions was beneficial to the construction of more compact three-dimensional structures, as well as to the rheology, texture, and water-holding capacity of A. pernyi pupa gels. However, excessive salt ions destroyed the gel structure. Our findings will aid the use of A. pernyi pupae as textural ingredients in formula foods.

Evaluation of Gelation Properties of Salt-Soluble Proteins Extracted from Protaetia brevitarsis Larvae and Tenebrio molitor Larvae and Application to Pork Myofibrillar Protein Gel System

The purpose of this study was to investigate the functional properties of salt-soluble proteins obtained from Protaetia brevitarsis (PB) and Tenebrio molitor (TM) larvae, the interaction between these proteins and pork myofibrillar protein (MP) in a gel system. The gel properties of salt-soluble protein extracts showed that the PB had a higher viscosity than the TM protein. However, the TM protein had higher gel strength compared with the PB protein. The gelation characteristics of the pork MP gel systems added with lyophilized insect salt-soluble protein powder showed to decrease slightly viscosity compared with MP alone. Adding the TM or PB protein powder did not affect the pork MP's hydrophobicity and sulfhydryl group levels. Furthermore, the protein bands of the MP did not change with the type or amount of insect salt-soluble protein. The cooking yields of the pork MP gels containing PB or TM protein powder were higher than those without insect protein. Regardless of the type of insect salt-soluble protein added, the pork MP's gel strength decreased. Furthermore, as the level of insect powder increased, the surface protein structure became rough and porous. The results demonstrated that proteins extracted from PB and TM larvae interfered with the gelation of pork MP in a gel system.

Differences in pork myosin solubility and structure with various chloride salts and their property of pork gel

The solubility and structure of myosin and the properties of pork gel with NaCl, KCl, CaCl2, and MgCl2 were investigated. Myofibrillar proteins (MPs) with phosphate were more solubilized with NaCl than with KCl (p < 0.05). CaCl2 and MgCl2 showed lower MP solubilities than those of NaCl and KCl (p < 0.05). The α-helix content of myosin was lower in KCl, CaCl2, and MgCl2 than in NaCl (p < 0.05). The pH of pork batter decreased in the order of KCl, NaCl, MgCl2, and CaCl2 (p < 0.05). The cooking yield of the pork gel manufactured with monovalent salts was higher than that of the pork gel manufactured with divalent salts (p < 0.05). The pork gel manufactured with KCl and MgCl2 showed lower hardness than that of the pork gel manufactured with NaCl. The solubility and structure of myosin were different with the different chloride salts and those led the different quality properties of pork gel. Therefore, the results of this study can be helpful for understanding the quality properties of low-slat meat products manufactured by replacing sodium chloride with different chloride salts.

Construction of whey protein gels prepared by three methods to stabilize high internal phase Pickering emulsions loaded with CoQ10 under different pH

The aim of this study was to investigate the effect of whey protein gel particles (WPGPs) prepared by heat-induced method, enzyme cross-linking method and calcium ion cross-linking method on the structural properties and intrinsic linkage of their stable high internal phase Pickering emulsions (HIPPEs) under different pH conditions. The effects of different pH and preparation methods on the internal interaction forces, particle size, ζ-potential, wettability and secondary structure of gels was investigated. The results indicated that the construction of HIPPEs system was successfully constructed at pH 3, 5 or 7. The WPGPs stabilized HIPPEs can maintain stable state at 4 °C for 28 days. Coenzyme Q10 (CoQ10) loaded with HIPPEs increased the bioavailability from 13.2% to 79.4%, which was demonstrated in in vitro digestion experiments.

Alternative Protein Sources and Novel Foods: Benefits, Food Applications and Safety Issues

The increasing size of the human population and the shortage of highly valuable proteinaceous ingredients has prompted the international community to scout for new, sustainable, and natural protein resources from invertebrates (e.g., insects) and underutilized legume crops, unexploited terrestrial and aquatic weeds, and fungi. Insect proteins are known for their nutritional value, being rich in proteins with a good balance of essential amino acids and being a valuable source of essential fatty acids and trace elements. Unconventional legume crops were found rich in nutritional, phytochemical, and therapeutic properties, showing excellent abilities to survive extreme environmental conditions. This review evaluates the recent state of underutilized legume crops, aquatic weeds, fungi, and insects intended as alternative protein sources, from ingredient production to their incorporation in food products, including their food formulations and the functional characteristics of alternative plant-based proteins and edible insect proteins as novel foods. Emphasis is also placed on safety issues due to the presence of anti-nutritional factors and allergenic proteins in insects and/or underutilized legumes. The functional and biological activities of protein hydrolysates from different protein sources are reviewed, along with bioactive peptides displaying antihypertensive, antioxidant, antidiabetic, and/or antimicrobial activity. Due to the healthy properties of these foods for the high abundance of bioactive peptides and phytochemicals, more consumers are expected to turn to vegetarianism or veganism in the future, and the increasing demand for such products will be a challenge for the future.

Recent Insight on Edible Insect Protein: Extraction, Functional Properties, Allergenicity, Bioactivity, and Applications

Due to the recent increase in the human population and the associated shortage of protein resources, it is necessary to find new, sustainable, and natural protein resources from invertebrates (such as insects) and underutilized plants. In most cases, compared to plants (e.g., grains and legumes) and animals (e.g., fish, beef, chicken, lamb, and pork), insect proteins are high in quality in terms of their nutritional value, total protein content, and essential amino acid composition. This review evaluates the recent state of insects as an alternative protein source from production to application; more specifically, it introduces in detail the latest advances in the protein extraction process. As an alternative source of protein in food formulations, the functional characteristics of edible insect protein are comprehensively presented, and the risk of allergy associated with insect protein is also discussed. The biological activity of protein hydrolyzates from different species of insects (Bombyx mori, Hermetia illucens, Acheta domesticus, Tenebrio molitor) are also reviewed, and the hydrolysates (bioactive peptides) are found to have either antihypertensive, antioxidant, antidiabetic, and antimicrobial activity. Finally, the use of edible insect protein in various food applications is presented.

Effect of Drying Methods on Physicochemical Characteristics and Functional Properties of Duck Blood Gel

The drying of duck blood provides safety and commercial benefits, but each drying method has its own characteristics. Moreover, information on the effects of diverse drying methods on the quality of duck blood is limited. This study aimed to investigate the effects of various drying methods on the chemical and functional properties of duck blood. The physicochemical characteristics and functional properties of duck blood subjected to spray drying (SD), freeze drying (FD), vacuum drying (VD), and hot air drying (HD) were examined. The carbonyl content of FD duck blood powder was the lowest and the thermal stability was higher than that of the other treatments (p<0.05). The gel obtained from spray-dried blood displayed the lowest malondialdehyde content. The hardness, gumminess, and chewiness were the highest in the heat-induced gel prepared from FD duck blood powder (p<0.05). The gel obtained from FD duck blood displayed a denser structure than the other gel samples. Taken together, the FD duck blood exhibited excellent chemical properties and processing suitability.

Physicochemical and textural properties of emulsions prepared from the larvae of the edible insects Tenebrio molitor, Allomyrina dichotoma, and Protaetia brevitarsis seulensis

The use of edible insects to replace meat protein is important to ensure future global food security. However, processed foods using edible insects require development to enhance consumer perception. Here, we examined the physicochemical characteristics and rheological properties of emulsions prepared from different edible insect larvae. Three edible insect species (Tenebrio molitor, Allomyrina dichotoma and Protaetia brevitarsis seulensis) were used to prepare larval emulsions that were formulated with 65% of insect larvae, 20% of pork back fat, and 15% ice. The A. dichotoma emulsion had the highest pH and lightness, redness, and yellowness values, while the T. molitor emulsion had the lowest pH and lightness, redness, and yellowness values. The T. molitor emulsion had the highest hardness, gumminess, chewiness, and apparent viscosity values but the lowest springiness and cohesiveness values. According to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, T. molitor had the thickest bands, followed by P. brevitarsis seulensis . The differential scanning calorimetry distributions for the T. molitor and A. dichotoma emulsions showed one peak, while that of the P. brevitarsis seulensis emulsion had two peaks. The collective results suggest that T. molitor was the most suitable candidate (of the three tested species) for use as a meat replacement in terms of its physicochemical and rheological properties. It is important that such properties of insect-based emulsions are maintained using various technologies.

Effect of Interaction between Mealworm Protein and Myofibrillar Protein on the Rheological Properties and Thermal Stability of the Prepared Emulsion Systems

In this study, we investigated the effect of replacing myofibrillar protein (pork ham) with edible insect proteins (Tenebrio molitor L.) in meat emulsion systems and examined the interaction between the two types of proteins. We also evaluated the rheological properties and thermal stability of these meat emulsions. The replacement ratios of myofibrillar protein and edible insect protein were as follows: 100:0 (EI0), 80:20 (EI20), 60:40 (EI40), 40:60 (EI60), 20:80 (EI80), and 0:100 (EI100). The pH, redness, and yellowness of the emulsion systems, after replacing myofibrillar protein with T. molitor protein, significantly increased with T. molitor protein concentrations. In contrast, the lightness, hardness, cohesiveness, gumminess, chewiness, apparent viscosity, and differential scanning calorimetry (DSC) of the emulsion systems decreased significantly with increasing T. molitor protein concentrations. The backscattering values of EI0, EI20, and EI40 decreased evenly in all spots of the dispersions as the storage time increased. Thus, up to 40% of pork myofibrillar protein could be replaced with T. molitor protein in meat emulsion systems. The results also suggest that the interaction between edible insect protein and myofibrillar protein degrades the rheological properties and thermal stability of the meat emulsion systems.