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Faster Upcoming Technology Uptake Relevant for the Environment in FOOds Drying

Periodic Reporting for period 2 - FUTURE-FOOD (Faster Upcoming Technology Uptake Relevant for the Environment in FOOds Drying)

Reporting period: 2016-09-01 to 2018-08-31

Publishable summary
FutureFood aims at demonstration and creating first market application of an eco-innovative food drying process. The process makes use of high pressure CO2 technology as drying medium which enables efficient drying at close-to-ambient temperatures in absence of oxygen. Earlier research and development studies have shown it feasibility of being an ecological and economical alternative to freeze-drying, for products categories vegetables and fruits, specialty ingredients such as proteins and biopolymers. Besides good preservation of a food quality, in-situ microbial inactivation promises to ensure additional food safety over other low-temperature drying process.
The main objectives were: (i) to minimize risks that could hamper the process to enter the market and (ii) to demonstrate its market replication potential via a first ready-to-market application.
In the project process extensions as well as candidate products have been prototyped to such level that it will increase the market potential.
Prototyping processing elements have demonstrated the energy reduction of the process and the full width of applications at a demonstration scale. For that purpose, an addition CO2 loop was installed to a pilot CO2 dryer for drying vegetable, fruits and herbs to enhance capture CO2 between batches and heat integration was performed, further decreasing the carbon footprint. Repetitive operation was conducted to assess issues hampering long-term processing stability. Pilot CO2 equipment was further modularly scaled-up for semi-continuous drying of sensitive ingredients to powders and microencapsulates. Energy consumption was determined and optimized, to be used as input for LCA analysis. Applying a user-friendly simplified LCA tool during process development, main LCA effects could be monitored at an early stage. Subsequent full LCA analysis for apple, e.g. showed that CO2 drying had better environmental performance than freeze drying, while hot air drying is slightly better than CO2 drying.
Product development led to understanding of scaling aspects and improvement of quality and taste for particularly dry healthy snack applications (fruits and vegetables) and industrial food applications such as instant foods (vegetables), bakery applications (fruits) and seasoning (herbs). Along the project, several scale-up hurdles have been taken and removed as risks for further implementation, including (food-grade) design aspects, product stability aspects. Product quality aspects have been addressed via sensory trials, through qualified panels and a range of audience groups along the food chain, including shelf-life testing.
Food safety benefits were further investigated at two lab scales and a pilot scale. Microbial inactivation was tested for coriander, apple and strawberry at lab scale for important pathogenic microorganisms (E. coli O157:H7, S. enterica, S. aureus, and L. monocytogenes), resulting 4-6 log CFE/g reductions, confirming that scCO2 drying is an efficient technology to reduce the microbial contamination in different food matrices at lab scale. Further food safety issues were determined, such as the effect of the process on fungal spores, the potential resistance of bacterial spores and the potential influence of the food pH on any resistance were investigated as well as potential presence of injured but viable cells that could retain their ability to produce toxins during the storage. Overall, these lab studies indicated that although CO2 drying has limitations regarding spores inactivation and removal of toxins, it is a promising technique for decontamination of vegetative cells and fungal spores. Large scale trials (160 liter) confirmed the inactivation capability for naturally present microorganisms, such as aerobic mesophilics, coliforms and enterobacteria. Using a risk assessment, the microbial safety and long term shelf life of CO2 dried foods was demonstrated using above data, showing it to have the potential to considerably raise the microbiological quality of dried products.
Demonstration of products such as apple and beetroot was performed in a near-industrial environment and products presented at a number of fairs, interested parties for review on taste, appearance and appeal, with overall positive review.
It can consequently be concluded that CO2 drying can interesting low-temperature drying technology with benefits in terms of environmental performance, food safety and food structure.
The project results demonstrate the industrial applicability of the process and provided the knowledge and know-how on microbial safety of the process, several scale-up aspects, product quality for a range of products, including pleasant sensoric attributes for consumers, as well as the operation procedures that allow a next-step in industrial implementation of the technology. LCA analyes for vegetables show that the process can have a considerable potential in reducing carbon footprint when replacing freeze-drying.
Scheme drying process