@misc{12876,
abstract = {{Carrot juice is valued for its high vitamin and antioxidant content, necessitating gentle thermal processing
to preserve these nutrients. Its slightly acidic pH value requires a two-step heating process, warranting
optimization to enhance product quality and resource efficiency. This study investigated the impact of
varying the first heating step between 100 and 130 °C on chemical, sensory, and microbiological parameters.
While other chemical parameters remained stable, lactic acid content increased significantly from 55 to 1405
mg/L over downtimes, highlighting the influence of external factors that could not be influenced within the
investigations. Lower heating temperatures compromised microbiological stability, with spore-forming
bacteria (5 colony forming units per 20 mL) detected at just a 10 °C reduction. Sensory quality showed
minimal change, with descriptive analysis identifying only 3 respectively 4 significantly different attributes
out of 19 across the factors experimental parameter setting and technical repetition. The quality of raw
materials had a more pronounced impact on sensory outcomes than the heating temperature. This study
concludes that adjusting the first heating temperature has limited benefits for sensory quality but risks
microbiological safety. Emphasis should therefore be placed on ensuring high-quality raw materials and
consistent raw juice properties to maintain product quality.}},
author = {{Weishaupt, Imke and Katsch, Linda and Sokolowsky, Martina and Schneider, Jan}},
booktitle = {{Brewing science : the scientific organ of the Weihenstephan Scientific Centre of the TU Munich, of Versuchs- and Lehranstalt für Brauerei in Berlin (VLB), of the Scientific Station for Breweries in Munich, of the Veritas laboratory in Zurich, of Doemens wba-Technikum Gmbh in Graefelfing/Munich = Monatsschrift für Brauwissenschaft}},
issn = {{1866-5195 }},
keywords = {{fractionated sterilization, carrot juice, descriptive analysis, microbiological stability}},
number = {{3/4}},
pages = {{17--26}},
publisher = {{Fachverlag Hans Carl GmbH}},
title = {{{Comparative study on the effect of mild temperature conditions in fractionated sterilization of carrot juice on microbiological stability and sensory properties}}},
doi = {{10.23763/BrSc25-04weishaupt}},
volume = {{78}},
year = {{2025}},
}
@misc{13084,
abstract = {{Thermal preservation is widely used for the stabilization of fruit and vegetable juices. However, this method can potentially impair product quality and it is necessary to categorize and quantify these changes in order to optimize the treatment process. Here, carrot juice was treated with different time temperature combinations selected to achieve equivalent microbiological lethality. Different temperatures were selected - low temperature long time (LTLT) with 90 and 95 °C and high temperature short time (HTST) with 120 and 125 °C. The thermally treated juice exhibited significant differences in physical, chemical and sensory parameters in contrast to untreated juice. HTST treatment had less of a negative effect on the juice. A significant deterioration in odor, appearance and taste was observed after the LTLT treatment compared to an untreated reference juice. The juice exhibited elevated acid taste, a shift in olfactory profile from white to red vegetables and diminished homogeneity. Significant changes in sugar composition, pH, carotenoids and color were also observed during this treatment. The juice that had been treated with LTLT exhibited a higher amount of monosaccharides, a lower pH value, a reduced quantity of carotenoids and a perceptible difference in color in comparison to the untreated and fresh juice. Therefore, it can be concluded that varying temperatures show different effects on juice quality, despite the same microbiological lethal effect. This must be taken into account when designing the pasteurization process.}},
author = {{Katsch, Linda and Weishaupt, Imke and Sokolowsky, Martina and Gibson, Brian R. and Schneider, Jan}},
booktitle = {{European Food Research and Technology}},
issn = {{1438-2385}},
keywords = {{Carrot juice, Sterilization, Carotenoids, Descriptive analysis, PCA, HTST}},
number = {{251}},
pages = {{3649--3668}},
publisher = {{Springer}},
title = {{{Impact of equivalent sterilization processes with different time- temperature combinations on the chemical, physical and sensory properties of carrot juice}}},
doi = {{https://doi.org/10.1007/s00217-025-04860-5}},
year = {{2025}},
}
@misc{13296,
author = {{Weishaupt, Imke and Begemann, Jens and Struck, Susanne and Matthäus, Bertrand and Schneider, Jan}},
location = {{Berlin}},
title = {{{Ressourceneffizientere Lebensmittelproduktion durch Umsetzung eines Raffineriekonzepts am Beispiel der Bierherstellung}}},
year = {{2025}},
}
@misc{11607,
abstract = {{Pasteurization of bottles and cans is an important technique for biological stabilization of beer as well as mixed beer drinks, malt beer and non-alcoholic beers. Despite recuperation, the heat requirement is very high and can be significantly reduced by lowering the maximum temperature in the pasteurizer. The current practice of calculating the lethal heat effect is based on the so-called beer formula using a globalized z-value for the temperature dependence of the inactivation. The premise experiments here is that for products containing sugar, such as malt beer, yeast cells pose the greatest danger. Therefore, the D values at various temperatures and the z values of three of the Krombacher Brewery's own yeasts (bottom-fermenting and top-fermenting) were determined in the laboratory using the capillary method. In a challenge test in the brewery, bottles with different products were inoculated with these yeasts and samples were taken from the industrial pasteurizer every two minutes and examined for viable cell counts. Accordingly, using specific D/z values, precise pasteurization can be achieved, the treatment temperature can be reduced to 55° C and 20-25% of energy can be saved.}},
author = {{Nolte, Jannik and Hense, Ludger and Weishaupt, Imke and Schneider, Jan}},
keywords = {{pasteurization, D value, z-value, heat energy savings, large scale trials, biological stability, yeast}},
location = {{Lille}},
title = {{{How do you turn a shotgun into a precision rifle - significant heat savings through the use of kinetic laboratory data (D/z values) in large-scale pasteurization}}},
year = {{2024}},
}
@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}},
}
@article{7090,
abstract = {{The conventional method for the determination of the lethal heat load during pasteurisation (expressed in so-called pasteurisation units (PU)) by measuring temperature and flow rate provides known inaccuracies and requires safety margins in terms of a planned over-pasteurisation to the detriment of the product quality. Based on the hypothesis that chemical conversions correlate with applied heat input, despite the differences in reaction kinetics between chemical conversion and microbiological inactivation, inline near infrared spectroscopy (NIRS) was investigated to identify and quantify applied PU. Acid hydrolytic sucrose degradation was confirmed a favourable marker reaction. In a first step by still using offline analytics (HPLC) and a calculation the feasibility and plausibility in principle could be proved. Compared with conventional PU deviation of only 0.3% were found when using the chemical marker reaction. However, the inline application using NIRS showed too high variations. The too low accuracy of the NIRS model for the sucrose measurement was identified of being the cause for failing the overall goal. Improvements in the inline determination seem to be promising.}},
author = {{Weishaupt, Imke and Neubauer, Peter and Schneider, Jan}},
issn = {{1613-2041}},
journal = {{Brewing science}},
keywords = {{near infrared spectroscopy, apple juice, pasteurisation, acid hydrolytic sucrose degradation, inline measure-ment of heat input, pasteurisation units}},
number = {{1/2}},
pages = {{1--8}},
publisher = {{Carl}},
title = {{{Approach to an inline monitoring of the heat impact in a high temperature short time treatment (HTST) of juice with the help of a chemical marker}}},
doi = {{10.23763/BrSc21-20weishaupt}},
volume = {{75}},
year = {{2022}},
}
@misc{7917,
author = {{Gossen, Arthur and Schwarzer, Knut and Weishaupt, Imke and Sürmeli, Baris Gün and Schneider, Jan}},
booktitle = {{Smarte Lösungen für eine nachhaltige Lebensmittelproduktion}},
location = {{Köln}},
title = {{{Flash Pasteurization with product and process monitoring using inline near infrared spectroscopy}}},
year = {{2022}},
}
@misc{8446,
author = {{Gossen, Arthur and Schwarzer, Knut and Sürmeli, Baris Gün and Weishaupt, Imke and Schneider, Jan}},
location = {{Madrid}},
title = {{{Smart Pasteurization Pilot Plant - a new approach with inline sensors towards a precise and gentle flash pasteurization}}},
year = {{2022}},
}
@misc{8450,
author = {{Schwarzer, Knut and Weishaupt, Imke and Gossen, Arthur and Sürmeli, Baris Gün and Schneider, Jan}},
location = {{Frankfurt}},
title = {{{Smart Pasteurization - Eine neuartige, autonome Regelung für eine Kurzzeiterhitzung}}},
year = {{2022}},
}
@article{5425,
abstract = {{The feasibility of inline classification and characterization of seven fruit juice varieties was investigated by the application of near-infrared spectroscopy (NIRS) combined with chemometrics. The findings are intended to be used to optimize the flash pasteurization of liquid foods. More precise information of the kind of product in real time had to be achieved to enable a more product-specific process. Using the method of partial least squares discriminant analysis, the fruit juice varieties were classified, showing a classification rate of 100% regarding an internal and 69% regarding an external test sets. A characterization by the extract content, pH value, turbidity, and viscosity was made by fitting a partial least squares regression model. The percentage prediction error of the pH value was <3% for internal and external test sets, and for the Brix value prediction errors were about 4% (internal) and 20% (external). The parameters viscosity and turbidity were found to be unsuitable. Despite this, the strategy applied to gain more product-specific information in real time showed to be feasible. By linking the results to a database containing potentially harmful microorganisms for various types of fruit juices, a more product-specific calculation of the necessary heat input can be performed. To demonstrate the practical relevance, a comparison between conventional and product-adapted process control was performed using two fruit varieties as examples in case of Alicyclobacillus acidoterrestris. Thus, with more accurate product information, achieved through the use of NIRS with chemometrics, a more precise calculation of the heat input can be achieved.}},
author = {{Weishaupt, Imke and Neubauer, Peter and Schneider, Jan}},
issn = {{2048-7177}},
journal = {{Food Science & Nutrition}},
keywords = {{flash pasteurization, fruit juice characterization and classification, inline near-infrared spectroscopy, multivariate data analysis}},
number = {{3}},
pages = {{800--812}},
publisher = {{Wiley}},
title = {{{Near-infrared spectroscopy for the inline classification and characterization of fruit juices for a product-customized flash pasteurization}}},
doi = {{ https://doi.org/10.1002/fsn3.2709}},
volume = {{10}},
year = {{2022}},
}
@article{6839,
abstract = {{Pasteurization is a crucial processing method in the food industry to ensure the safety of consumables. A major part of contemporary pasteurization processes involves using flash pasteurizer systems, where liquids are pumped through a pipe system to heat them for a predefined time. Accurately monitoring the amount of heat treatment applied to a product is challenging. This monitoring helps ensure that the correct heat impact (expressed in pasteurization units) is applied, which is commonly calculated as a product of time and temperature, taking achievability of the inactivation of the microorganisms into account. The state-of-the-art method involves a calculation of the applied pasteurization units using a one-point temperature measurement and the holding time for this temperature. Concerns about accuracy lead to high safety margins, reducing the quality of the pasteurized product. In this study, the applied pasteurization level was estimated using regression models trained with NIR spectroscopy data collected while pasteurizing fruit juices of different types and brands. Several conventional regression models were trained in combination with different preprocessing methods, including a novel prediction outlier detection method. Generalized juice models trained with the concatenated data of all types of juices demonstrated cross-validated scores of RMSECV ∼2.78 ± 0.09 and r2 0.96 ± 0.01, while separate juice models displayed averaged cross-validated scores of RMSECV ∼1.56 ± 0.04 and r2 0.98 ± 0.01. Thus, the model accuracy ±10–30 % is well within the standard safety margins. }},
author = {{Sürmeli, Baris Gün and Weishaupt, Imke and Schwarzer, Knut and Moriz, Natalia and Schneider, Jan}},
issn = {{1751-6552}},
journal = {{Journal of Near Infrared Spectroscopy}},
keywords = {{Beverage pasteurization, heat impact control, prediction outlier elimination}},
number = {{6}},
pages = {{339--351}},
publisher = {{Sage Publishing}},
title = {{{Heat impact control in flash pasteurization by estimation of applied pasteurization units using near infrared spectroscopy}}},
doi = {{10.1177/09670335211057233}},
volume = {{29}},
year = {{2021}},
}
@article{5424,
abstract = {{Near infrared spectroscopy in combination with a transflection probe was investigated as inline measurement in a continuous flash pasteurizer system with a sugar-water model solution. Robustness and reproducibility of fluctuations of recorded spectra as well as trueness of the chemometric analysis were compared under different process parameter settings. Variable parameters were the flow rate (from laminar flow at 30 L/h to turbulent flow at 90 L/h), temperature (20 to 100 degrees C) and the path length of the transflection probe (2 and 4 mm) while the pressure was kept constant at 2.5 bar. Temperature and path length were identified as the most affecting parameters, in case of homogenous test medium. In case of particle containing systems, the flow rate could have an impact as well. However, the application of a PLS model, which includes a broad temperature range, and the correction of prediction results by applying a polynomial regression function for prediction errors, was able to compensate these effects. Also, a path length of 2 mm leads to a higher accuracy. The applied strategy shows that by the identification of relevant process parameters and settings as well as the establishment of a compensation strategy, near infrared spectroscopy is a powerful process analytical tool for continuous flash pasteurization systems.}},
author = {{Weishaupt, Imke and Zimmer, Manuel and Neubauer, Peter and Schneider, Jan}},
isbn = {{0022-1147}},
issn = {{1750-3841}},
journal = {{Journal of Food Science}},
keywords = {{flash pasteurization, inline near infrared spectroscopy, multivariate data analysis, process condition influences, sugar-water-solution model beverage}},
number = {{7}},
pages = {{2020 -- 2031}},
title = {{{Model based optimization of transflection near infrared spectroscopy as a process analytical tool in a continuous flash pasteurizer}}},
doi = {{10.1111/1750-3841.15307}},
volume = {{85}},
year = {{2020}},
}
@inproceedings{5437,
author = {{Schwarzer, Knut and Katsch, Linda and Weishaupt, Imke and Schneider, Jan}},
location = {{München}},
title = {{{Cyberphysisches System zur thermischen Entkeimung von Getränken}}},
year = {{2019}},
}
@inproceedings{5465,
author = {{Schneider, Jan and Weishaupt, Imke and Schwarzer, Knut and Katsch, Linda}},
location = {{München}},
title = {{{Cyberphysisches System zur thermischen Entkeimung von Getränken}}},
year = {{2019}},
}
@inproceedings{5469,
author = {{Weishaupt, Imke and Zimmer, Manuel and Schneider, Jan}},
location = {{Sevilla}},
title = {{{Gentle Flash Pasteurization of Fruit Juices through Product Identification and Characterization using Near-Infrared Spectroscopy as Inline Analytical Method}}},
year = {{2019}},
}
@inproceedings{5473,
author = {{Sürmeli, Baris Gün and Weishaupt, Imke and Schwarzer, Knut and Schneider, Jan}},
title = {{{Beverage Classification Using Linear Discriminant Analysis with Covariance Matrix Shrinkage}}},
year = {{2019}},
}
@inproceedings{5475,
author = {{Schneider, Jan and Conradi, Florian and Wefing, Patrick and Weishaupt, Imke and Zimmer, Manuel and Schwarzer, Knut}},
location = {{Lemgo}},
title = {{{Muss man die Aufheizzonen einer KZE in die PE-Berechnung einbeziehen?}}},
year = {{2019}},
}
@inproceedings{5476,
author = {{Schneider, Jan and Zimmer, Manuel and Weishaupt, Imke and Schattenberg, Britta and Conradi, Florian and Schwarzer, Knut}},
location = {{Bielefeld}},
title = {{{Lebensmittelverschwendung – Welchen Beitrag kann die Digitalisierung leisten? }}},
year = {{2019}},
}