Browsing by Person "Herrmann, Kurt"

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Characterization of the aroma profile of food smoke at controllable pyrolysis temperatures
(2023) Rigling, Marina; Höckmeier, Laura; Leible, Malte; Herrmann, Kurt; Gibis, Monika; Weiss, Jochen; Zhang, Yanyan
Smoking is used to give food its typical aroma and to obtain the desired techno-functional properties of the product. To gain a deeper knowledge of the whole process of food smoking, a controllable smoking process was developed, and the influence of wood pyrolysis temperature (150–900 °C) on the volatile compounds in the smoking chamber atmosphere was investigated. The aroma profile of smoke was decoded by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Subsequently, the correlations in the most important substance classes, as well as in individual target components, were investigated by the Pearson test. Phenols and lactones showed an increase over the entire applied temperature range (rT = 0.94 and rT = 0.90), whereas furans and carbonyls showed no strict temperature dependence (rT < 0.6). Investigations on single aroma compounds showed that not all compounds of one substance class showed the same behavior, e.g., guaiacol showed no significant increase over the applied pyrolysis temperature, whereas syringol and hydoxyacetone showed a plateau after 450 °C, and phenol and cyclotene increased linear over the applied temperature range. These findings will help to better understand the production of aroma-active compounds during smoke generation in order to meet consumers preferences.
Effect of smoldering air volume flow rates and smoking time on quality attributes of Frankfurter-type sausages
(2025) Leible, Malte; Herrmann, Kurt; Gibis, Monika; Weiss, Jochen; Leible, Malte; Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21/25, 70599, Stuttgart, Germany; Herrmann, Kurt; Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21/25, 70599, Stuttgart, Germany; Gibis, Monika; Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21/25, 70599, Stuttgart, Germany; Weiss, Jochen; Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21/25, 70599, Stuttgart, Germany
This study explores the effects of varying smoking conditions on the properties of Frankfurter-type sausages. Using a modified smoldering smoke generator, air volume flow rate and smoking time were varied to assess their impact on color, texture, and sensory characteristics. The results showed significant changes in these characteristics and a wide spectrum in smoke color was produced across the 14 different settings. L* values ranged from 64.32 ± 0.61 to 46.33 ± 0.78, a* values ranged from 11.81 ± 0.29 to 24.18 ± 0.39, b* values ranged from 14.93 ± 0.77 to 41.20 ± 1.25 with an increase in smoking time and air volume flow generally leading to a darker smoking color. Sensory test regarding color showed that the perceived color behaved similarly to the measured color. In these descriptive tests the perceived color ranged from 0.42 ± 0.42 to 9.67 ± 0.43 on a scale from 0 to 10. Smoke odor did not show the strong differences seen in the other results. Here the perceived smoke odor ranged from 4.76 ± 2.00 to 8.64 ± 1.03 on a scale from 0 to 10. Since the study was based on a statistical experimental plan, a predictive model based on a surface plot could be established. These findings provide valuable insights in the qualitative changes in Frankfurter -Type sausages for optimizing smoking parameters in the food industry, potentially enabling precise control over desired sensory and physical properties in smoked meat products.
Time-delayed cold gelation of low-ester pectin and gluten with CaCO3 to facilitate manufacture of raw-fermented vegan sausage analogs
(2025) Koenig, Maurice; Ahlborn, Kai; Herrmann, Kurt; Loeffler, Myriam; Weiss, Jochen; Kolanowski, Wojciech
To advance the development of protein-rich plant-based foods, a novel binder system for vegan sausage alternatives without the requirement of heat application was investigated. This enables long-term ripening of plant-based analogs similar to traditional fermented meat or dairy products, allowing for refined flavor and texture development. This was achieved by using a poorly water-soluble calcium source (calcium carbonate) to introduce calcium ions into a low-ester pectin—gluten matrix susceptible to crosslinking via divalent ions. The gelling reaction of pectin–gluten dispersions with Ca 2+ ions was time-delayed due to the gradual production of lactic acid during fermentation. Firm, sliceable matrices were formed, in which particulate substances such as texturized proteins and solid vegetable fat could be integrated, hence forming an unheated raw-fermented plant-based salami-type sausage model matrix which remained safe for consumption over 21 days of ripening. Gluten as well as pectin had a significant influence on the functional properties of the matrices, especially water holding capacity (increasing with higher pectin or gluten content), hardness (increasing with higher pectin or gluten content), tensile strength (increasing with higher pectin or gluten content) and cohesiveness (decreasing with higher pectin or gluten content). A combination of three simultaneously occurring effects was observed, modulating the properties of the matrices, namely, (a) an increase in gel strength due to increased pectin concentration forming more brittle gels, (b) an increase in gel strength with increasing gluten content forming more elastic gels and (c) interactions of low-ester pectin with the gluten network, with pectin addition causing increased aggregation of gluten, leading to strengthened networks.