TY - JOUR A1 - Borremans, An A1 - Bußler, Sara A1 - Sagu Tchewonpi, Sorel A1 - Rawel, Harshadrai Manilal A1 - Schlüter, Oliver K. A1 - Leen, Van Campenhout T1 - Effect of blanching plus fermentation on selected functional properties of mealworm (Tenebrio molitor) powders JF - Foods : open access journal N2 - The aim of this study was to determine the effect of blanching followed by fermentation of mealworms (Tenebrio molitor) with commercial meat starter cultures on the functional properties of powders produced from the larvae. Full fat and defatted powder samples were prepared from non-fermented and fermented mealworm pastes. Then the crude protein, crude fat, and dry matter contents, pH, bulk density, colour, water and oil binding capacity, foaming capacity and stability, emulsion capacity and stability, protein solubility, quantity of free amino groups, and protein composition of the powders were evaluated. Regardless of the starter culture used, the blanching plus fermentation process reduced the crude and soluble protein contents of the full fat powders and in general impaired their water and oil binding, foaming, and emulsifying properties. Defatting of the powders improved most functional properties studied. The o-phthaldialdehyde assay revealed that the amount of free amino groups was higher in the fermented powders while sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that the soluble proteins of the fermented powders were composed of molecules of lower molecular mass compared to non-fermented powders. As molecular sizes of the soluble proteins decreased, it was clear that the protein structure was also modified by the fermentation process, which in turn led to changes in functional properties. In general, it was concluded that fermentation of mealworms with blanching as a pre-treatment does not contribute to the functional properties studied in this work. Nevertheless, the results confirmed that the properties of non-fermented powders are comparable to other food protein sources. KW - mealworm KW - fermentation KW - functional properties KW - insect proteins KW - SDS-PAGE Y1 - 2020 U6 - https://doi.org/10.3390/foods9070917 SN - 2304-8158 VL - 9 IS - 7 PB - MDPI CY - Basel ER - TY - GEN A1 - Hass, Roland A1 - Sandmann, Michael A1 - Reich, Oliver T1 - Photonic sensing in highly concentrated biotechnical processes by photon density wave spectroscopy T2 - Proceedings SPIE 10323, 25th International Conference on Optical Fiber Sensors N2 - Photon Density Wave (PDW) spectroscopy is introduced as a new approach for photonic sensing in highly concentrated biotechnical processes. It independently quantifies the absorption and reduced scattering coefficient calibration-free and as a function of time, thus describing the optical properties in the vis/NIR range of the biomaterial during their processing. As examples of industrial relevance, enzymatic milk coagulation, beer mashing, and algae cultivation in photo bioreactors are discussed. KW - Photon Density Wave Spectroscopy KW - multiple light scattering KW - fermentation KW - algae cultivation KW - process analytical technology KW - fiber spectroscopy Y1 - 2017 SN - 978-1-5090-4850-2 U6 - https://doi.org/10.1117/12.2263617 SN - 0277-786X SN - 1996-756X VL - 10323 PB - IEEE CY - New York ER - TY - JOUR A1 - Sagu Tchewonpi, Sorel A1 - Rawel, Harshadrai M. A1 - Rohn, Sascha T1 - Targeted bottom-up mass spectrometry approach for the relative quantification of post-translational modification of bovine κ-casein during milk fermentation JF - Molecules N2 - kappa-casein (kappa-CN) is one of the key components in bovine milk, playing a unique role in the structuration of casein micelles. It contains in its chemical structure up to sixteen amino acid residues (mainly serine and threonine) susceptible to modifications, including glycosylation and phosphorylation, which may further be formed during milk processing. In this study, changes in post-translational modification (PTM) of kappa-CN during bovine milk fermentation were investigated. One-to-five-day fermented milk samples were produced. A traditional bottom-up proteomics approach was used to establish a multiple-reaction monitoring (MRM) method for relative quantification of kappa-CN PTM. Endoproteinase Glu-C was found to efficiently digest the kappa-CN molecule. The developed LC-MS method was validated by performing assessments of linearity, precision, repeatability, reproducibility, limit of detection (LOD), and limit of quantification (LOQ). Among the yielded peptides, four of them containing serine and threonine residues were identified and the unmodified as well as the modified variants of each of them were relatively quantified. These peptides were (1) IPTINTIASGEPTSTTE ([140, 158]), (2) STVATLE ([162, 168]), (3) DSPE ([169, 172]), and (4) INTVQVTSTAV ([180, 190]). Distribution analysis between unmodified and modified peptides revealed that over 50% of kappa-CN was found in one of its modified forms in milk. The fermentation process further significantly altered the composition between unmodified/modified kappa-CN, with glycoslaytion being predominant compared to phosphorylation (p < 0.01). Further method development towards alpha and beta-CN fractions and their PTM behavior would be an asset to better understand the changes undergone by milk proteins and the micellar structure during fermentation. KW - bovine milk KW - fermentation KW - kappa-casein KW - post-translational modifications KW - glycosylation KW - phosphorylation KW - mass spectrometry Y1 - 2022 U6 - https://doi.org/10.3390/molecules27185834 SN - 1420-3049 VL - 27 IS - 18 PB - MDPI CY - Basel ER -