Periodic Reporting for period 2 - HiStabJuice (Establishing a strong and lasting international training network for innovation in food and juice industries: a 4D-research approach for fruit juice processing)
Reporting period: 2022-11-01 to 2025-02-28
HiStabJuice was a European intersectoral and interdisciplinary network offering research training to 11 ESRs, which was relevant to the entire food industry worldwide. Initiated by the International Fruit and Vegetable Juice Association (IFU), the ETN combined the scientific expertise of 5 universities and 3 research institutions with the technological experience of 10 industry partners from 7 EU countries. This ETN stood out by its exceptionally high industrial involvement that ensured training in real-world abilities and in solving key problems with exceptional analytical and technological skills, combined with training in key transferable skills for public and private sector employment. The ESRs worked together on the evaluation of various factors influencing colour stability in fruit juices, focussing on raw materials and preservation techniques, as well as associated effects, deleterious to the health benefits of the final products. Pioneering aspects included the first empirical analysis of the contribution to colour stability and nutritional value of thermostable enzymes, fruit variety, ripeness, harvest time, traditional and modern preserving techniques (pasteurization, freezing, pulsed electric field, ohmic heating, high-pressure processing), which were evaluated in a 4D approach (microbes, enzymes, nutrients and chemical-physical parameters). Upon conclusion of the action, the ESRs had established a universal, empirical system for deciding which fruit types to harvest at which times, at which stage of the ripening process, and which preservation method would give the best colour and nutrient stability. In line with the Horizon2020 strategic priority of Open Science, this knowledge was made freely accessible. This has the potential to revolutionise the fruit juice industry and fortify the European industry for decades to come. The participation of IFU guaranteed unsurpassed intercommunication between the ETN and industry stakeholders across the EU.
WP 3 had a dual focus, investigating the role of microbes on the shelf-life one side and on the enzymes on reduced colour stability on the other side. Surrogate strains for EHEC and Salmonella were successfully identified and could be used in WP5 as model organisms. Kinetics of pathogens and suitable surrogates were determined in different juices. The impact of different thermal and non-thermal treatments on the global gene expression of selected strains was investigated. The matrix impact on thermal resistance of bacteria was analyzed.
The overall progress of WP4 (ESRs 3, 4, 5, 7, 11)was exceptionally high, almost overfulfilling the expectations. The ESRs analysed a large spectrum of different fruit quality aspects, as well as harvesting and processing regimes. This included an initial screening of more than 100 strawberry varieties for colour stability during processing identified two promising candidates of potential commercial interest and resulted in a colour stability prediction value (ESR5). The main outcome was that cultivar has a strong impact, more than harvest time which is more important than ripening stage. In addition, proanthocyanidin contents and the presence of epiafzelechin in proanthocyanidins correlated with low colour stability in nectars. In contrast, a low pectin's arabinan to galactan ratio correlated with high colour stability in nectars (ESR11). Of course, not all of the identified colour stable cultivars would be of agronomic relevance (poor performance with respect to yield, fruit size and abiotic and biotic stress tolerance), but we identified several promising breeding lines in the pipeline, which will probably become available to the market in the next years. Thus, specific cultivation of colour stable cultivars for processing and the use of overripe strawberries harvested late in the season would significantly increase the shelf-life of strawberry nectars.
In WP5, multivitamin analysis methods using HPLC-MS/MS were developed for the water-soluble B and C vitamins (ESR10). The work concentrated on defined and prepared raw materials (strawberry nectar, raspberry juice, sour cherry juice) and managed a number of challenges in establishing the logistics for large-scale fruit purchasing, processing, and sample distribution to ensure uniformity and traceability of samples, with analytical tasks distributed according to ESSR’s laboratory specialization. Microbial inactivation kinetics using surrogate microorganisms for all preservation technologies was conducted. Specific kinetic and validation studies for PEF, ohmic, and HPP technologies were performed and standardized processing parameters for all treatments were established and applied. This systematic approach ensures that the comparison of conventional and non-conventional preservation treatments is scientifically rigorous, reproducible, and relevant for both food safety and product quality objective.
The overall progress of WP4 (ESRs 3, 4, 5, 7, 11)was exceptionally high, almost overfulfilling the expectations. The ESRs analysed a large spectrum of different fruit quality aspects, as well as harvesting and processing regimes. This included an initial screening of more than 100 strawberry varieties for colour stability during processing identified two promising candidates of potential commercial interest and resulted in a colour stability prediction value (ESR5). The main outcome was that cultivar has a strong impact, more than harvest time which is more important than ripening stage. In addition, proanthocyanidin contents and the presence of epiafzelechin in proanthocyanidins correlated with low colour stability in nectars. In contrast, a low pectin's arabinan to galactan ratio correlated with high colour stability in nectars (ESR11). Of course, not all of the identified colour stable cultivars would be of agronomic relevance (poor performance with respect to yield, fruit size and abiotic and biotic stress tolerance), but we identified several promising breeding lines in the pipeline, which will probably become available to the market in the next years. Thus, specific cultivation of colour stable cultivars for processing and the use of overripe strawberries harvested late in the season would significantly increase the shelf-life of strawberry nectars.
In WP5, multivitamin analysis methods using HPLC-MS/MS were developed for the water-soluble B and C vitamins (ESR10). The work concentrated on defined and prepared raw materials (strawberry nectar, raspberry juice, sour cherry juice) and managed a number of challenges in establishing the logistics for large-scale fruit purchasing, processing, and sample distribution to ensure uniformity and traceability of samples, with analytical tasks distributed according to ESSR’s laboratory specialization. Microbial inactivation kinetics using surrogate microorganisms for all preservation technologies was conducted. Specific kinetic and validation studies for PEF, ohmic, and HPP technologies were performed and standardized processing parameters for all treatments were established and applied. This systematic approach ensures that the comparison of conventional and non-conventional preservation treatments is scientifically rigorous, reproducible, and relevant for both food safety and product quality objective.
The project went beyond the state of the art by developing and validating innovative food processing strategies that integrated biotechnological and engineering solutions to enhance the quality, health benefits, and sustainability of plant-based food products. Through interdisciplinary collaboration, the consortium combined enzymatic and microbial treatments with emerging technologies such as pulsed electric fields, enabling higher retention of functional compounds and greater process efficiency. Data-driven modelling and optimisation approaches were also explored, laying the groundwork for the intelligent control of processing conditions in future industrial applications.
By effectively working together on collaborative workpackages, HiStabJuice ESRs have achieved great strides overall. During the project period, 15 papers were successfully published, 10 were submitted, and several more were either submitted or in progress. ESR7 obtained the Young Mind Award at the European Horticulture Congress (SHE 2024) held in Bucharest, Romania 2024. ESR10 obtained the AOAC INTERNATIONAL/SCIEX Rising Star Scholarship (https://www.aoac.org/2023-annual-meeting-exposition/2023-aoac-awards/(opens in new window)) and the 2024 Quality Juice Award at the Juice Summit in Antwerp (https://www.qualityjuice.org/quality-juice-award(opens in new window)).
The expected impacts of this work extend well beyond the project’s duration. The developed methods and prototypes offer a strong basis for the production of next-generation functional foods with improved nutritional profiles and consumer appeal. These innovations have the potential to strengthen the competitiveness of European food producers, particularly SMEs, by enabling more sustainable and value-added product lines. The project’s findings are also anticipated to support policy development related to health claims, food labelling, and sustainable production practices. Ultimately, the project is expected to contribute to healthier diets, reduced food system environmental impacts, and increased resilience and innovation capacity within the European agri-food sector.
By effectively working together on collaborative workpackages, HiStabJuice ESRs have achieved great strides overall. During the project period, 15 papers were successfully published, 10 were submitted, and several more were either submitted or in progress. ESR7 obtained the Young Mind Award at the European Horticulture Congress (SHE 2024) held in Bucharest, Romania 2024. ESR10 obtained the AOAC INTERNATIONAL/SCIEX Rising Star Scholarship (https://www.aoac.org/2023-annual-meeting-exposition/2023-aoac-awards/(opens in new window)) and the 2024 Quality Juice Award at the Juice Summit in Antwerp (https://www.qualityjuice.org/quality-juice-award(opens in new window)).
The expected impacts of this work extend well beyond the project’s duration. The developed methods and prototypes offer a strong basis for the production of next-generation functional foods with improved nutritional profiles and consumer appeal. These innovations have the potential to strengthen the competitiveness of European food producers, particularly SMEs, by enabling more sustainable and value-added product lines. The project’s findings are also anticipated to support policy development related to health claims, food labelling, and sustainable production practices. Ultimately, the project is expected to contribute to healthier diets, reduced food system environmental impacts, and increased resilience and innovation capacity within the European agri-food sector.