@misc{13271,
  abstract     = {{Pasteurization is the prevalent method for stabilizing cloudy apple juice and prolonging its shelf life, but can also impair quality. Therefore, it is necessary to investigate and quantify the chemical, physical and sensory effects of this treatment. In this study, cloudy apple juice was treated at different time-temperature combinations with equivalent microbial lethality with 161.6 PU. These can be categorized as low temperature/long time (LTLT with 70°C and 80°C) or high temperature/short time (HTST with 90°C, 100°C and 105°C) treatments. The results were compared to those of untreated juice. HTST treatment had significantly less impact on the juice compared to LTLT treatment. LTLT-treated juices were characterized by different sensory attributes, such as raisin and caramel odor and bitter taste. In contrast, the untreated and HTST-treated juices exhibited odors like pear and lemon. There were also significant differences in turbidity, sugar composition, viscosity and a heightened 5-(hydroxymethyl)furfural (HMF) content with LTLT treatment. In summary, HTST-treated juices are more similar to the untreated juices and are rated higher in terms of quality characteristics. The lowest pasteurization temperature of 70°C results in the greatest deterioration of juice quality. It can be concluded that different pasteurization conditions showed different effects on juice quality, despite having the same microbiological lethality of 161.6 PU. Results can be considered when designing pasteurization processes.}},
  author       = {{Katsch, Linda and Sokolowsky, Martina and Gibson, Brian and Schneider, Jan}},
  booktitle    = {{Applied Food Research}},
  issn         = {{2772-5022}},
  keywords     = {{Cloudy apple juice, HTST, juice pasteurization, sensory analysis, process optimization, equivalent microbial lethality}},
  number       = {{2}},
  publisher    = {{Elsevier}},
  title        = {{{Influence of different pasteurization conditions with equivalent pasteurization units on chemical, physical, and sensory properties of cloudy apple juice}}},
  doi          = {{10.1016/j.afres.2025.101471}},
  volume       = {{5}},
  year         = {{2025}},
}

@phdthesis{13335,
  abstract     = {{The process of thermal preservation of liquid foods is a safety-relevant process step in the processing of products such as fruit juices and is associated with a high-energy expenditure and safety margin. There are already various approaches to improve this conventionally managed process step in terms of product and resource preservation. Compared to these novel technologies, the use of real-time process analytics offers great potential to improve already existing process plants by implementing inline capable process analytical tools. This allows direct control of the reactions taking place and changes during the running process. Instead of post process, random product control, quality control during the process can be made rendered. The chemical and pharmaceutical industry serves as a reference industry for the use of process analytical tools, although the reactions and product matrices are less complex. In the food industry, on the other hand, there is a greater variation in raw materials and intermediate products. In addition, a large number of reactions can take place in parallel within a process, and the physical states and properties of the individual components can vary. A uniform set of rules for the use of process analytical tools does not exist here. Each product, each process provides its own research potential, so that a large research gap opens up in the area of the food industry.
In order to contribute to closing this gap, this thesis presents a novel approach to improve the process of pasteurization of liquid food. For fruit juices as an application, near infrared spectroscopy in combination with chemometric methods was applied to make the process more product specific. Based on known weaknesses of the process, the relevant aspects for a product-specific treatment were identified. In the further course, the suitability of near infrared spectroscopy as a process analytical tool in the process of pasteurization was verified. Moreover, it was investigated whether a sufficiently accurate identification of the product type as well as the microbiologically relevant properties can be achieved by the application of chemometric methods. In the course of this, the suitability of the measurement methodology was confirmed and solutions were established for any process influences. The product classification and description of the microbiologically relevant parameters extract content and pH value were also implemented with sufficient accuracy. Knowing the destruction kinetics of relevant microorganisms, the product-specific determination of target values for the necessary lethal heat input could be realized. In addition, an analysis of the actual values was carried out on the basis of a chemometric regression method by inferring the microbiological pasteurization effect through the chemical reaction of acid hydrolytic sucrose degradation by means of the indirect approach. This required knowledge of the chemical reaction kinetics and mahematical modeling of the degradation behavior. The novel approach could be confirmed by calculations using results from off-line analysis, whereas the use of near infrared spectroscopy as an inline method still revealed potential for optimization with respect to measurement accuracies.
In summary, the results of this work provide a promising opportunity to make conventional processes for the preservation of liquid foods more product-specific by using near-infrared spectroscopy as an inline-capable and multimodal sensor technique, leading to an increase in process efficiency and product quality.}},
  author       = {{Weishaupt, Imke}},
  keywords     = {{fruit juice pasteurization, near infrared spectroscopy, process optimization, multivariate statistics, inline process analytics, Fruchtsaftpasteurisation, Prozessoptimierung, Nahinfrarotspektroskopie, multivariate Statistik, Inline-Prozessanalytik}},
  pages        = {{144}},
  publisher    = {{Technische Universität Berlin}},
  title        = {{{Near infrared spectroscopy as inline analytical tool to optimize the pasteurization process of liquid foods}}},
  doi          = {{https://doi.org/10.14279/depositonce-17804}},
  year         = {{2023}},
}