Evaluating the potential of high pressure high temperature and thermal processing on volatile compounds, nutritional and structural properties of orange and yellow carrots

The present study compares the impact of thermal and high pressure high temperature(HPHT) processing on volatile profile (via a non-targeted headspace fingerprinting) and structural and nutritional quality parameter (via targeted approaches) of orange and yellow carrot purees. The effect of oil enrichment was also considered. Since oil enrichment affects compounds volatility, the effect of oil was not studied when comparing the volatile fraction. For the targeted part, as yellow carrot purees were shown to contain a very low amount of carotenoids, focus was given to orange carrot purees. The results of the non-targeted approach demonstrated HPHT processing exerts a distinct effect on the volatile fractions compared to thermal processing. In addition, different colored carrot varieties are characterized by distinct headspace fingerprints. From a structural point of view, limited or no difference could be observed between orange carrot purees treated with HPHT or HT processes, both for samples without and with oil. From nutritional point of view, only in samples with oil, significant isomerisation of all-trans-β-carotene occurred due to both processing. Overall, for this type of product and for the selected conditions, HPHT processing seems to have a different impact on the volatile profile but rather similar impact on the structural and nutritional attributes compared to thermal processing

Сетевая система контроля технологического процесса выращивания полупроводниковых кристаллов и тонких пленок

Экспериментальное моделирование аппаратно-программного обеспечения показало достаточную надежность работы системы и значительное уменьшение трудоемкости контроля и управления параметрами технологического процесса

Texture and interlinked post-process microstructures determine the in vitro starch digestibility of Bambara groundnuts with distinct hard-to-cook levels

© 2019 Elsevier Ltd Particular storage conditions are described to promote the development of the hard-to-cook (HTC) phenomenon for most legumes. However, it is not clearly established whether the HTC phenomenon influences starch digestion kinetics. Therefore, this study explored how the HTC phenomenon influences in vitro starch digestion of Bambara groundnuts, taking into account three distinct HTC levels. Stored Bambara groundnuts required prolonged cooking times. Increasing storage time led to a decrease in the rate constant of texture degradation, signifying the development of the HTC phenomenon. For cooking times of 60 min and 120 min, high HTC level samples exhibited higher rate constants and extents of starch digestion compared to the fresh sample. The higher rate of digestion was attributed to the high hardness that resulted in greater cell rupture and faster access of amylase to starch. Adapting cooking times of Bambara groundnuts with distinct HTC levels to obtain equivalent hardness values and microstructures resulted in comparable starch digestion kinetics. Spectrophotometric analysis overestimated the amount of digested starch, in contrast to the more accurate HPLC analysis, which further provided more insight by quantifying multiple digestion products. This work demonstrates that it is the hardness and interlinked pattern of cell failure (microstructure) that determines starch digestion of Bambara groundnuts with distinct HTC levels.status: publishe

Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be optimized. To this end, this work aimed at the development of an ovomucoid-based indicator with combined pressure temperature dependent inactivation kinetics and a sufficient pressure temperature stability relevant for commercial HPHT sterilization. After varying buffer type and the pH at ambient pressure and temperature (pHi), an indicator based on 1 g/L ovomucoid in 0.1 M MES-NaOH buffer pHi 6.2 was selected. The inactivation behavior of this indicator system is characterized by pressure temperature dependent (combined Arrhenius–Eyring) first-order kinetics in the processing domain relevant for HPHT sterilization. This indicator showed good integrating properties under isobaric–isothermal and dynamic pressure temperature conditions. In a temperature uniformity study of a vertically oriented, pilot-scale HPHT vessel, pTTI readouts at different coordinates illustrated low and high temperature zones. As the inactivation of spores under HPHT is clearly positively temperature dependent, the food safety objective has to be verified in the former sampling zone

Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be optimized. To this end, this work aimed at the development of an ovomucoid-based indicator with combined pressure temperature dependent inactivation kinetics and a sufficient pressure temperature stability relevant for commercial HPHT sterilization. After varying buffer type and the pH at ambient pressure and temperature (pHi), an indicator based on 1 g/L ovomucoid in 0.1 M MES-NaOH buffer pHi 6.2 was selected. The inactivation behavior of this indicator system is characterized by pressure temperature dependent (combined Arrhenius–Eyring) first-order kinetics in the processing domain relevant for HPHT sterilization. This indicator showed good integrating properties under isobaric–isothermal and dynamic pressure temperature conditions. In a temperature uniformity study of a vertically oriented, pilot-scale HPHT vessel, pTTI readouts at different coordinates illustrated low and high temperature zones. As the inactivation of spores under HPHT is clearly positively temperature dependent, the food safety objective has to be verified in the former sampling zone

Headspace fingerprinting as an untargeted approach to compare novel and traditional processing technologies: A case-study on orange juice pasteurisation

As a rule, previous studies have generally addressed the comparison of novel and traditional processing technologies by a targeted approach, in the sense that only the impact on specific quality attributes is investigated. By contrast, this work focused on an untargeted strategy, in order to take into account unexpected and unintended effects of (novel) processing, and to possibly uncover unknown compounds resulting from alternative processing. The potential of headspace GC–MS fingerprinting was explored as a tool to compare the impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurisation of orange juice. This study demonstrated that when processing conditions are selected based on equivalent microbial safety, the impact of heat, HP and PEF pasteurisation on the volatile profile of orange juice can be considered comparable. During refrigerated storage, however, indirect impact differences were revealed, which were attributed to differences in degree of enzyme inactivatio

Headspace fingerprinting as an untargeted approach to compare novel and traditional processing technologies: A case-study on orange juice pasteurisation

As a rule, previous studies have generally addressed the comparison of novel and traditional processing technologies by a targeted approach, in the sense that only the impact on specific quality attributes is investigated. By contrast, this work focused on an untargeted strategy, in order to take into account unexpected and unintended effects of (novel) processing, and to possibly uncover unknown compounds resulting from alternative processing. The potential of headspace GC–MS fingerprinting was explored as a tool to compare the impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurisation of orange juice. This study demonstrated that when processing conditions are selected based on equivalent microbial safety, the impact of heat, HP and PEF pasteurisation on the volatile profile of orange juice can be considered comparable. During refrigerated storage, however, indirect impact differences were revealed, which were attributed to differences in degree of enzyme inactivatio

Thermal versus high pressure processing of carrots: A comparative pilot-scale study on equivalent basis

This report describes the first study comparing different high pressure (HP) and thermal treatments at intensities ranging from mild pasteurization to sterilization conditions. To allow a fair comparison, the processing conditions were selected based on the principles of equivalence. Moreover, pilot- and industrial-scale equipment were opted for, supporting conditions close to industrial application. The overall impact on carrot quality was characterized by analyzing a wide range of quality attributes, including specific (micro)nutrients (carotenoids and sugars), process-induced contaminants (furfural and 5-hydroxymethylfurfural), enzyme activities (pectin methylesterase and peroxidase) and other relevant quality aspects (texture, dry matter content and color). This study demonstrated that the potential benefit of HP over thermal processing of carrots is largely dependent on the processing intensity applied. Thermal sterilization affected carrot quality the most, while mild and severe thermal pasteurization, mild and severe HP pasteurization and HP sterilization resulted in a comparable overall quality. Industrial relevance: The extensive nature of this investigation and the corresponding results can be considered of key importance for further implementation of HP technology in the food industry, since a correct and complete assessment of process-induced changes is of major importance in the context of legislative aspects of novel processing technologies

Thermal versus high pressure processing of carrots: A comparative pilot-scale study on equivalent basis

This report describes the first study comparing different high pressure (HP) and thermal treatments at intensities ranging from mild pasteurization to sterilization conditions. To allow a fair comparison, the processing conditions were selected based on the principles of equivalence. Moreover, pilot- and industrial-scale equipment were opted for, supporting conditions close to industrial application. The overall impact on carrot quality was characterized by analyzing a wide range of quality attributes, including specific (micro)nutrients (carotenoids and sugars), process-induced contaminants (furfural and 5-hydroxymethylfurfural), enzyme activities (pectin methylesterase and peroxidase) and other relevant quality aspects (texture, dry matter content and color). This study demonstrated that the potential benefit of HP over thermal processing of carrots is largely dependent on the processing intensity applied. Thermal sterilization affected carrot quality the most, while mild and severe thermal pasteurization, mild and severe HP pasteurization and HP sterilization resulted in a comparable overall quality. Industrial relevance: The extensive nature of this investigation and the corresponding results can be considered of key importance for further implementation of HP technology in the food industry, since a correct and complete assessment of process-induced changes is of major importance in the context of legislative aspects of novel processing technologies