Influence of the Protein Content on Fiber Morphology and Heat Treatment of Electrospun Potato Protein–Maltodextrin Fibers

Abstract

The production of ultrafine fibers of proteins and polysaccharides by needleless electrospinning can be performed prior to a thermal treatment to form glycoconjugates via the first stage of the Maillard reaction. The aim was to produce potato protein–maltodextrin conjugates with a varying protein content of 0.05, 0.1, 0.15, and 0.2 g/mL by needleless electrospinning and subsequent thermal treatment (0, 6, 12, 24, and 48 h at 65 °C and 75% relative humidity). The concentrations of the maltodextrins, with a dextrose equivalent of 2 and 21, were kept constant at 0.8 and 0.1 g/mL. The highest fiber production rate was achieved with a protein content of 0.1 g/mL (5.8 ± 0.4 g/h). With increasing protein content, the production rate decreased to 2.8 ± 0.5 g/h. The fibers obtained from the spinning solution containing 0.2 g/mL protein showed the largest average diameter (4.0 ± 1.5 µm) and the broadest fiber diameter distribution. The protein content of the fibers was close to that of the corresponding spinning solution. The browning index after 48 h of heating increased for all samples (9.7–14.7) compared to the unheated samples (1.1–3.3). The results indicate that the protein content has an impact on the yield, the fiber diameter, and the morphology of the fibers.

Effects of Electrospun Potato Protein–Maltodextrin Mixtures and Thermal Glycation on Trypsin Inhibitor Activity

“…The electrospun fibers were prepared as recently described in [ 32 ]. Each solution was prepared with 80 g maltodextrin MD DE2 and 10 g maltodextrin MD DE21, and an addition of potato protein powder of 5, 10, 15, or 20 g, respectively.…”

“…After stirring, the blend solution was degassed under vacuum (~600 mbar, 25 °C) for 30 min and electrospun by needleless electrospinning [ 5 , 32 ]. The electrospinning equipment (Technical workshop of the University of Hohenheim) contained a spinneret block, a grounded collector, a command block, and a high voltage supply (SL 60, Spellman, Hauppauge, NY, USA).…”

“…Each blend of the electrospun fibers was subjected to a thermal treatment (65 °C and 75% RH for 0, 6, 12, 24, and 48 h in a climate cabinet (HCP 50, Memmert GmbH + Co. KG, 91126, Schwabach, Germany). The fiber production rate was 3–6 g/h [ 32 ]. The heated and unheated electrospun fibers were finely ground into powder for further analysis [ 32 ].…”

“…The fiber production rate was 3–6 g/h [ 32 ]. The heated and unheated electrospun fibers were finely ground into powder for further analysis [ 32 ].…”

“…Some studies have already addressed the possibility of glycation of electrospun fibers prepared from whey, soy, or pea protein with dextrans or maltodextrins [ 5 , 26 , 27 , 30 , 31 ]. The preparation of electrospun potato protein-maltodextrin fibers followed by thermal treatment was presented in a recent study [ 32 ]. The formation of conjugates between proteins and polysaccharides can not only lead to improved functional properties of the proteins, but also to structural changes, which can influence their biological activity [ 33 ].…”