Sustainable food process engineering
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Date
2023
Authors
Bremenkamp, Ina
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University College Cork
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Abstract
Food is a basic need and food packaging plays an important role in providing safe food to the world. Food packaging innovations in the past were important milestones for the development of the food sector, by ensuring safety, prolonging quality, and enabling the current supply chain. Nevertheless, the focus has drifted and innovations in the food sector are starting to be driven by ecological needs. The current food packaging options present challenges due to the dependency on fossil raw materials and the accumulation of durable single used packaging waste. Therefore, food packaging innovations need to be adjusted to the new demands, by not being an environmental burden, but still providing product protection, safety, and supporting various supply chains. Design strategies as eco-packaging design, circular economy design and design for recycling are important drivers. Furthermore, the development, improvement, and standardisation of biopolymers for replacing fossil sourced packaging materials are being widely studied. This opens up opportunities for relieving the current environmental burden of food packaging.
This thesis focuses on alternative food packaging for ready to eat (RtE) seafood products, a food category that ultimately provides healthy and convenient food to consumers. RtE is a food product group with increasing turnovers, supporting different life styles, e.g., eating on the go, fast and simplified product preparation as well as healthy eating. Seafood products provide essential nutrients and are a valuable food source, rich in nutrients that are particularly important for elderly people, a growing consumer group all over the world. The objective of this thesis was the investigation of biobased edible coatings as sustainable packaging development for RtE seafood products by using a quantitative methodology. A quantitative packaging development approach, in contrast to the often-used qualitative approach in industry, supports an optimal packaging material selection based on the product characteristics and its potential supply chain.
Currently a challenging task in the development of eco-food packaging systems is the assessment of the environmental burden. Every action or product has an environmental impact, but the environmental impact can be significantly influenced by the selected options. A systematic review of existing life cycle assessments (LCA) for investigating environmental challenges of novel food packaging systems in the field of RtE fish and meat products was undertaken and revealed a significant impact of the selected LCA approach on the evaluated environmental impact, highlighting the importance of transparent LCA studies, using fair comparisons and a holistic scope. A step by step approach by shifting the LCA focus to different objectives, such as the whole food-packaging system, comparing different packaging materials and systems, is recommended to allow a comprehensive understanding of the environmental impact of food-packaging system. This enables industry stakeholders to make informed decisions, taking an active role that balance necessity, wastefulness, and creating efficient and sustainable packaging solutions.
A critical review of edible coatings for chilled RtE food products was also performed to understand the state of the art and identify knowledge gaps for further developments. Edible coatings have been studied for RtE food products mainly to improve the microbiological stability; with other quality parameters receiving much less attention. Only few products within the RtE seafood category were tested in combination with edible coatings. Edible coatings can be sourced from natural resources, including land or marine based biomass. The direct use of food resources as packaging can create a burden on the food supply chain. The conversion of food industry waste products to edible coatings allows an optimal use of the full harvested biomass, but has some challenges, e.g., volume availability, collection, and possible high energy demand during transformation. Also, during the selection of an edible coating material, the supply chain impact should be reviewed, and additionally industrial scale up feasibility should be assessed for a successful industrial application. Biobased materials often have a limited potential, but by combining multiple biobased materials, the coating properties can be optimised. Aspects considered included the methodology for coating application, assessment of coating performance, and edible coating challenges as part of the food system were also discussed. Edible coatings are a complex topic but provide an interesting approach for developing eco-food packaging systems.
Developing a tailored packaging system for a RtE seafood product requires the identification of critical quality parameters and understanding of the influence of environmental conditions on the product quality. Therefore, the degradation process of two RtE seafood products, a RtE baked fish product and a RtE minced fish patty, were investigated by studying the microbiological, chemical, and physical properties. The studied sorption isotherm behaviour showed a sigmodal shape, and the best model fitting was reached with the Peleg model, followed by the Guggenheim-Anderson-de Boer (GAB) model. The storage experiments revealed that water loss and microbial growth are important product quality parameters for both tested RtE seafood products, while fat oxidation was only a critical quality parameter for RtE seafood products with a higher fat content. By understanding the underlying reaction of degradation processes and the effect of environmental factors such as oxygen, light, and relative humidity, the required packaging properties were identified.
The application of chitosan and alginate coatings for RtE baked fish products were studied. A full factorial experimental design was used to investigate the effect of coating material composition on microbial growth, water loss and lipid oxidation under optimal (4°C) and abuse (14°C) storage conditions. A 3^2 full factorial design was used to study the effect of chitosan concentration (1, 2 and 3%), and glycerol concentration (0, 15 and 30% w/w chitosan). The effect of the composition of an alginate coating was studying with a 2^3 full factorial design. The studied factors were alginate concentration (1 or 2% (w/v)), glycerol concentration (0 or 1.5% (w/w) alginate) and crosslinking the alginate coating with CaCl2 to form calcium alginate (yes/no). The results showed that a chitosan coating with 1% (w/v) chitosan in 1% (v/v) acetic acid, and 15% (w/w chitosan) glycerol, or 1% (w/v) alginate coating with no glycerol, and no crosslinking showed the best performance in controlling the tested safety and quality parameters. Additionally, a full experimental factorial design was performed to study the combined effect of an alginate and chitosan coating applied as a double coating, and single coating. The double coating tested did not provide a combined product protection. A desirability method was used to identify the shelf life of chitosan, alginate and double coated RtE products based on multi quality parameters. It was concluded that chitosan coated samples showed the best performance with a three- fold shelf life extension compared to uncoated products.
Improving product safety and quality by combining different protection methods, known as hurdle technology, is a common approach. The applied hurdles can differ. Well applied examples are sanitizing, packing and cold storage for fruits and vegetables. A novel sanitizing system consists of the use of cold plasma treatment, avoiding the use of chemicals to reduce microbiological contamination and increase safety. The combination of cold plasma treatment and an equilibrium modified atmosphere packaging (EMAP) for cherry tomatoes was investigated under controlled temperature (10 and 20°C) throughout storage. Statistical analysis of the results showed that plasma treatment did not negatively affect the quality of the product. A higher microbiological growth was detected within the packed cherry tomatoes, while a plasma treatment before packing reduced growth of microorganism during the early days of storage. Package was important to prevent weight loss and changes in total soluble solid content over 14 days of storage. The combination of cold plasma, temperature and EMAP design ensured the quality retention of cherry tomatoes, which suggests that they have potential to be used as hurdle technology.
A packaging based on an edible coating, requires a second packaging component which can be a packaging film. Combining the edible coating and an outside layer should provide an optimal product protection over the required shelf life. A mathematical modelling approach was taken to estimate the required water barrier properties for the packaging film material. The water loss was identified as the remaining most critical quality parameter after a chitosan coating was applied. Film materials were selected based on their properties and end of life options, and the water vapour barrier properties at lower storage temperatures were tested. The water vapour transmission rate (WVTR) allowing a water loss of 10% within 21 days was calculated using the GAB model, and using a linear approximation of the isotherm was estimated to be 94 and 81 g/m2 day, respectively. The simplified linear model showed similar results to the GAB model approach for predicting moisture loss of a high moisture food product. When increasing the required shelf life only a small reduction of the WVTR was seen. Testing the WVTR at chilled storage conditions showed that depending on the material selected, the temperature can impact the water vapour barrier of the packaging film materials, especially for biobased materials. The recommended film material in combination with a chitosan edible coating for a RtE baked fish product was a cellulose based compostable film.
Food packaging is essential but only with efficient solutions, an open mind and with various approaches the negative effects of food packaging on the environment can be tackled. Special emphasis should be given to food packaging that allows to use naturally available protection systems. It was highlighted that including circular economy aspects and environmental considerations during all development stages of a food packaging improves the sustainability of a packed food product. An integrated precision packaging, based on an edible coating and a film layer, for RtE seafood products can be an eco-packaging solution, without compromises in food safety and quality.
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Keywords
Food packaging , Edible coatings , Sustainable packaging
Citation
Bremenkamp, I. 2023. Sustainable food process engineering. PhD Thesis, University College Cork.