1. Final Report Summary - REPRO (Reducing Food Processing Waste)
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Abstract: The overall aim of this study was to develop advanced methods to enable total transformation of food-processing-derived plant-based organic waste co-products into high added value food and feed products. This has been achieved by focusing the multidisciplinary expertise of a pan-European team of participants on four key scientific and technical objectives:
1) to develop approaches and procedures as means to obtain traceable, microbiologically safe and stable co-products for partners during project and protocols for implementation after project;
2) to develop precision enzyme-based bioprocesses to deconstruct and tailor co-product components;
3) to integrate the enzyme-based bioprocesses with advanced physical processes, thereby developing hybrid bio-processing systems;
4) to minimise market risk by: (a) ensuring socioeconomic and environmental acceptability of new processes and products by the consumer, retailer, and regulator (fork-to-farm concept); (b) developing sustainable dissemination and exploitation routes via stakeholder interaction platforms, and an international, web-based dissemination platform to link co-product producers, users and process Research and development (R&D) experts.
The work performed was divided into the following six work packages (WPs):
- development of approaches and procedures for microbiological safety, stability and co-product traceability (WP 1)
- development of precision enzyme-based bioprocesses to deconstruct and tailor co-product components (WP 2)
- the integration the bioprocesses with advanced physical processes, thereby developing hybrid processing systems incorporating closed-loop water-recycling activities (WP 3)
- ensuring acceptability of new processes and products by the consumer, retailer, and regulator (WP 4)
- development of sustainable dissemination and exploitation routes (WP 5).
REPRO collaborative research was used to develop (enzyme-based) biotools for the controlled deconstruction of co-products. Selected commercially-sourced enzymes had their activity profiles determined to standardise assay procedures and dosing protocols. Recombinant enzymes were also considered, including a cutinase produced within REPRO. Biotools were integrated with advanced processing technologies to produce novel and innovative products. Microbial modelling led to the development of protocols which successfully stabilised co-products, minimised microbial hazards during processing and extended the shelf life of the final products.
Three generic processes for plant co-product valorisation were developed:
- extrusion processing with and without the involvement of bio-processing;
- enzyme-aided fractionation of spent grain to provide routes for protein and functional saccharide products;
- enzymatic liquefaction or enzyme-aided fractionation of vegetable trimmings to isolate pectins and phytochemicals.
The developmental research explored how the manipulation of the activity profile of an enzyme cocktail can strongly affect the chemistry and macromolecular properties of isolated products; an important consideration when correlating enzyme activity requirements for the selective solubilisation or modification of the cell wall matrix.
Two scenarios were selected from the generic process development to be mathematically modelled using chemical engineering principles. Each model was evaluated for socioeconomic and environmental acceptability (farm-to-fork).
Scenario 1: Production of snacks by extrusion of BSG evaluated snacks based on whole spent grain and chick-pea flour. Summarised results, reflecting a REPRO-developed 'traffic light' code for process acceptability, showed:
- energy: highly acceptable (best-case scenario)
- microbiological safety: safe products
- Life cycle assessment (LCA): environmentally more acceptable than production of feed or disposal in landfill
- legislative compliance: novel foods legislation has to be addressed for spent grain use as an ingredient in products created
- consumer acceptability: acceptable; (with reservations)
- cost / benefit analysis: acceptable (could be improved by ingredient replacement manipulation).
Scenario 2: Liquefaction of vegetable trimmings involved the extraction of phytochemical-rich juice and the enzymatic release of specialised pectins showed:
- energy: energy efficiency is crucial; (acceptable only in best-case scenario)
- microbiological safety: safe products
- LCA: environmentally more acceptable than production of feed or disposal in landfill but enzyme production: energy costs important
- legislative compliance: acceptable; due to use of approved methods and familiar food-grade ingredients
- consumer acceptability: acceptable (with reservations)
- cost / benefit analysis: may be acceptable but some scenarios (processing costs and energy efficiency) are seen as expensive.
Overall, the exploitation of spent grain by incorporation into snack products and vegetable trimmings by liquefaction and fractionation are highly positive, with the caveat that compliance with current novel foods legislation is required.
The third bio-process developed: the partial liquefaction of spent grain was not as comprehensively modelled and evaluated. The process showed that economically important components, including peptides, water-soluble antioxidants, and fibre-rich residues could be produced, but a cursory evaluation highlighted the requirement for large quantities of enzymes. This presented a significant energy and environmental burden, which would require further targeted research and development to find high activity and robust enzymes, which would have a bearing on the future for the exploitation of ligno-cellulosic residues through biotechnological approaches, e.g. for bioalcohol production.
The targeted exploitation programme within REPRO demonstrated the successful incorporation and evaluation, through feed trials, of spent grain as a protein source in fish feed. This has led to the filing of a patent. Furthermore, the potential to exploit novel fibre products, based on cereal residues, and rheologically-active pectins, has been demonstrated and evaluated in emulsion-based dairy food systems.
In conclusion, REPRO demonstrated that biotechnology, in conjunction with modern processing systems, has the potential to deliver achievable co-product exploitation. Underpinning this approach is the demonstrated ability to liberate valuable constituents from readily available low-value by-products for commercial and sustainable use. This is perceived as becoming increasingly important and relevant to the industrial exploitation of nutrient-rich co-products in the food chain and to help alleviate building pressures on the economics of a sustainable world food supply. REPRO delivered a user-friendly and cost-effective way to identify and evaluate a range of important risk criteria and the use of a predictive simulation tool facilitates the analysis of costs, benefits and risks associated with exploitation of food-grade processing waste streams (both generic and local). The introduction of virtual processing scenarios demonstrated their advantage to focus where information gaps exist. Hence, areas requiring further research could be readily identified.