Browsing by Person "Schmidt, Florian"

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Storable cheese curd—effect of milk homogenization as a pre-treatment and freezing and extrusion of cheese curd on production of pasta filata style cheese
(2024) Schmidt, Florian; Graf, Britta; Hinrichs, Jörg
This study investigates the production of pasta filata style cheese from a storable, frozen intermediate material. Homogenization (2–16 MPa, single-staged) of milk (fat/protein = 0.9) was used as a tool to decrease fat globule size and consequently fat losses. Plasticization was achieved by using a single-screw extruder set up with double-jacketed hot water cycle. Non-frozen and frozen cheese curd as well as the extruded pasta filata style cheese pre-treated with different homogenization pressure was analyzed regarding the thermo-rheological properties. Fat and protein gain/loss during extrusion was evaluated by analyzing fat in dry matter (FDM) and protein in dry matter (PDM) before and after extrusion. Homogenization of cheese milk leads to a reduction of tan δ for thereof produced raw cheese curd material as well as the extruded products. Freezing and extrusion counteract the reduction of tan δ . A homogenization pressure of 8 MPa is sufficient to prevent fat losses during extrusion while still maintaining plasticization of the product for fresh and frozen material, respectively. The FDM after extrusion is 0.8% higher for fresh material and 4.9% higher for frozen material, which means that the fat concentrates during extrusion due to water loss. Moreover, there is no loss of PDM for all samples, regardless of the homogenization pressure. A combination of homogenization pressure, freezing, and extrusion leads to a plasticizable product without losses of fat and protein. Hence, frozen cheese curd can be used as a storable intermediate.
Upscaling of alkaline pea protein extraction from dry milled and pre-treated peas from laboratory to pilot scale: Optimization of process parameters for higher protein yields
(2022) Schmidt, Florian; Blankart, Max; Wanger, Janina; Scharfe, Markus; Scheuerer, Theresa; Hinrichs, Jörg
The upscaling of pea protein extraction from laboratory scale with a centrifuge to pilot scale with a decanter centrifuge was investigated, and the pea protein extraction efficiency from dry milled and pre-treated peas was compared. Upscaling from laboratory to pilot scale is possible since starch was under the limit of detection (< 0.5%). The protein banding pattern of a sodium-dodecyl-sulfate polyacrylamide gel electrophoresis confirmed that albumins and globulins were extracted by alkali extraction. Protein yield increased from 59.5% to 67.1% for dry milled peas due to constant and quick discharge of dry matter in the decanter centrifuge. For pre-treated peas, the protein yield increased from 60.3% to 94.3%, which is explained by an improved cutting and improved separation in pilot scale compared to laboratory scale. The impact of acceleration, mass flow, differential speed and their respective interactions in the decanting process was determined with a design of experiments. For dry milled peas, only the mass flow exceeded the significance level. However, a mass flow of 5 kg h −1 , an acceleration of 1000 g ×and a differential speed of 50 min −1 led to the highest protein yield of 75.6%. The obtained protein yields for the pre-treated peas were in the range of 83 to 96% and therefore did not show significant differences in protein yield.