Effect of High Hydrostatic Pressure Intensity on Structural Modifications in Mealworm (Tenebrio molitor) Proteins.

Processing edible insects into protein extracts may improve consumer acceptability. However, a better understanding of the effects of food processing on the proteins is needed to facilitate their incorporation into food matrices. In this study, soluble proteins from Tenebrio molitor (10% w/v) were pressurized using high hydrostatic pressure (HHP) at 70-600 MPa for 5 min and compared to a non-pressurized control (0.1 MPa). Protein structural modifications were evaluated using turbidity measurement, particle-size distribution, intrinsic fluorescence, surface hydrophobicity, gel electrophoresis coupled with mass spectrometry, and transmission electron microscopy (TEM). The observed decrease in fluorescence intensity, shift in the maximum emission wavelength, and increase in surface hydrophobicity reflected the unfolding of mealworm proteins. The formation of large protein aggregates consisting mainly of hexamerin 2 and ⍺-amylase were confirmed by protein profiles on gel electrophoresis, dynamic light scattering, and TEM analysis. The typical aggregate shape and network observed by TEM after pressurization indicated the potential involvement of myosin and actin in aggregate formation, and these were detected by mass spectrometry. For the first time, the identification of mealworm proteins involved in protein aggregation phenomena under HHP was documented. This work is the first step in understanding the mealworm protein-protein interactions necessary for the development of innovative insect-based ingredients in food formulations.

Impact of invasive insects on native insect communities.

Several biophysical factors are leading to the loss of biodiversity, among them the dominance of exotic invasive species on native communities is important. Their dominance can lead to changes in the structure of insect communities, by competing and displacing native species to other crops or habitats. These changes can impact the herbivore's natural enemies in invaded areas by diverging them from suitable herbivores and altering their biological control process. The development of edible insects and derived products at an industrial scale can also have an impact on the local fauna by the risks of spillover and accidental release in nature. Several area-wide integrated pest management programs are also using the sterile insect technique to control insect pests and disease' vectors. This technique is becoming largely used; however, its application as 'non-intrusive to the environment' is controversial particularly when eradication is concerning species that are at the basis of food webs.

High Hydrostatic Pressure-Assisted Enzymatic Hydrolysis Affect Mealworm Allergenic Proteins.

Edible insects have garnered increased interest as alternative protein sources due to the world's growing population. However, the allergenicity of specific insect proteins is a major concern for both industry and consumers. This preliminary study investigated the capacity of high hydrostatic pressure (HHP) coupled to enzymatic hydrolysis by Alcalase® or pepsin in order to improve the in vitro digestion of mealworm proteins, specifically allergenic proteins. Pressurization was applied as pretreatment before in vitro digestion or, simultaneously, during hydrolysis. The degree of hydrolysis was compared between the different treatments and a mass spectrometry-based proteomic method was used to determine the efficiency of allergenic protein hydrolysis. Only the Alcalase® hydrolysis under pressure improved the degree of hydrolysis of mealworm proteins. Moreover, the in vitro digestion of the main allergenic proteins was increased by pressurization conditions that were specifically coupled to pepsin hydrolysis. Consequently, HHP-assisted enzymatic hydrolysis represents an alternative strategy to conventional hydrolysis for generating a large amount of peptide originating from allergenic mealworm proteins, and for lowering their immunoreactivity, for food, nutraceutical, and pharmaceutical applications.

Impacts of the carbonyl group location of ester bond on interfacial properties of sugar-based surfactants: experimental and computational evidences.

Interfacial properties of surfactants are dependent on the conformation adopted by the hydrophilic headgroup or/and the hydrophobic tail at the boundary limit of two immiscible phases. Here, we demonstrate the impacts of the carbonyl group (-CO-) location of the ester bond of sugar-based surfactants by comparing some properties of two closely related esters, octyl glucuronate and glucose octanoate, at the air-water interface. The carbonyl group location influences the rate and extent of interfacial adsorption and the rheology properties of sugar esters at the air-water interface, which were evaluated by dynamic surface tension and complex surface viscoelastic measurements. Octyl glucuronate adsorbs the fastest at the air-water interface whereas glucose octanoate reduces the dynamic surface tension at the lowest value and exhibits the highest film viscoelasticity. Differences are attributed to molecular conformation constraints inducing relevant changes to the surface coverage kinetic capacity and the interaction strengths of the octyl sugar ester adsorbed films at the air-water interface. All of the results are supported by the minimum cross-sectional area values per molecule determined by both experimental and computational approaches.