AiF 20271N - Differentiation of pasteurized fruit juices

The aim of this research project is to differentiate between orange and apple juices with alternative preservatives[1], conventionally pasteurized juices and raw juices, both in terms of their key aroma profiles and sensory profiles, as well as in terms of their analytical distinctiveness. The latter is being implemented by validating specific marker compounds over the shelf life and in juices produced using a combination process. In addition, an analytical method is to be created that will serve as a quick testing tool for quality control and food monitoring and help detect and prevent consumer deception.


[1] Using high pressure treatment and treatment with pulsed electric fields

The research project identified marker compounds that allow a distinction between thermally pasteurized, HPP- and PEF-treated chilled not-from-concentrate juices. For orange juice, two volatile markers could be validated: vanillin, whose increased concentration indicates thermal treatment, and (S)-carvone, which was detected in significantly higher concentrations in HPP-treated juice. The combination of these two markers also allows conclusions to be drawn about double treatment, since an increased (S)-carvone concentration indicates HPP, while the vanillin content indicates prior thermal treatment.
Volatile markers for differentiating the processes could also be identified in apple juice. 3H-2-benzofuran-1-one, ethyl hexanoate and 1-octen-3-one were validated as indicators of thermal treatment. Furthermore, ethylhexanoate could be used to distinguish between HPP and PEF juices, while 3H-2-benzofuran-1-one can indicate double thermal treatment.
In addition, non-volatile markers were determined using a non-targeted approach. For orange juice, two markers for HPP, two for PEF and two for thermal treatment could be validated, some of which were also detected in commercial industrial juices. For apple juice, one marker for HPP/PEF treatment and one specific marker for PEF were identified. These marker compounds were characterized in terms of their elemental composition to enable a database comparison.
The results were verified over the storage period and in juices that had been treated twice, but further validation with a larger number of samples is necessary to make generally valid statements. While it is possible to clearly distinguish between thermally treated juices and HPP juices, PEF could not be clearly distinguished from purely thermal processes due to the higher temperatures during treatment. The identified marker compounds could contribute to food monitoring and to avoiding misleading marketing in the area of gently pasteurized, chilled not-from-concentrate juices in the future.

BMWK - IGF - AiF - FEI

Industrielle Gemeinschaftsforschung (IGF)