Prof Debbie Rees is a plant physiologist working on the handling and storage of perishable plant produce. She has been working for the NRI since 1994. Early work at NRI focused on improving postharvest handling of sweet potato in East Africa. Subsequently, she broadened her research area to cover postharvest technology for a wide range of perishable crops both in the UK and overseas. Current/recent projects focus on apple, pear, broccoli, swede and cabbage in the UK, on yams in West Africa, sweet potato in East Africa as well as high value commodities imported into the UK such as avocado, grape.

Debbie was appointed as a Reader in Plant Physiology in 2003, and as Professor in Plant Physiology in 2022. She is joint lead for the Produce Quality Centre (PQC), a collaborative research centre with NIAB based around postharvest facilities run by the University which focusses on developing, testing and evaluating new technologies, products or produce to improve storage and shelf-life of produce.

A wide-ranging career started with a PhD at Oxford University investigating the use of phosphorus Nuclear Magnetic Resonance to study energy metabolism in human muscle and bacteria. Following a one year fellowship at the Baylor College of Medicine in Houston, Texas, she then spent five years as a post-doctoral researcher studying photosynthetic mechanisms at Sheffield University, followed by 2 years working in the Wheat programme at CIMMYT (International Centre for Wheat and Maize) in Mexico.

Books edited

1. Rees, D., Orchard, J.E. and Farrell, G. (eds) (2012) Crop Post-Harvest: Science and Technology Volume 3: Perishables Wiley Blackwell, UK

2. Rees, D., van Oirschot, Q and Kapinga, R. (eds) (2003) Sweetpotato post-harvest Assessment: Experiences from East Africa. Chatham, UK. Natural Resources Institute.

Scientific Papers

1. Fisher, Rosalind , Thurston, Karen, Colgan, Richard and Rees, Deborah  (2023) Monitoring low O2 stress in apples: what we can learn from chlorophyll fluorescence and respiratory characteristics. Postharvest Biology and Technology, 208:112661. ISSN 0925-5214 (Print), 1873-2356 (Online) (doi:https://doi.org/10.1016/j.postharvbio.2023.112661)

2. Kumar, R., Rees, D. and Fisher, L.H.C. (2022) Preserving food without creating plastic pollution: A primer on progress in developed and low- to middle-income countries. Enterprise Development and Microfinance, 33:4, 1–17 https://doi.org/10.3362/1755-1986.22-00073

3. Fisher, L., and Rees, D. (2022) The effect of wash water chlorine content on the pinking discolouration of fresh cut Iceberg lettuce. International Journal of postharvest Technology and Innovation, 8 no 2—3 https://doi.org/10.1504/IJPTI.2022.121880

4. Rees, D., Bishop, D. ,Schaefer, J., Colgan, R., Thurston, K. Fisher, R. and Duff, A. (2021) SafePod: a respiration chamber to characterise apple fruit response to storage atmospheres. . Postharvest Biology and Technology 181, 111674 https://doi.org/ 10.1016/j.postharvbio.2021.111674

5. Sharma, S.K., McLean, K., Colgan, R., Rees, D., Young, S., Sønderkær, M., Terry, L. A., Turnbull, C., Taylor, M. A. and Bryan, G. J. (2021) Combining conventional QTL analysis and whole-exome capture-based bulk-segregant analysis provides new genetic insights into tuber sprout elongation and dormancy release in a diploid potato population. Heredity, 127 (3). pp. 253-265. ISSN 0018-067X (doi: https://doi.org/10.1038/s41437-021-00459-0 )

6. Apolot, M.G., Acham, H., Ssozi J., Namutebi, A., Masanza, M., Kizito, E. and Rees, D. (2020) Postharvest practices along supply chains of Solanum aethiopicum (Shum) and Amaranthus lividus (Linn) leafy vegetables in Wakiso and Kampala districts, Uganda. African Journal of Food, Agriculture, Nutrition and Development 20(03):15978-15991 DOI: 10.18697/ajfand.91.177715

7. Mignouna, D.B., Akinola, A.A., Abdoulaye, T., Alene, A., Manyong, V.M., Maroya, N., Aighewi, B., Kumar, L., Balogun, M., Lopez-Montes, A., Quain, M.D. Rees, D., and Asiedu, R. (2020) Potential returns to yam research investment in sub-Saharan Africa and beyond. Outlook on Agriculture 49(2):003072702091838 DOI: 10.1177/0030727020918388

8. Akanyijuka, S., Acham, H., Gaston, T., Namutebi, A., Masanza, M., Jagwe, J.,N., Kasharu, A., Kizito E. and Rees, D. (2018) Effect of different processing conditions on proximate and bioactive contents of Solanum aethiopicum (Shum) powders, and acceptability for cottage scale production. American Journal of Food and Nutrition, 6 (2). pp. 46-54. ISSN 2374-1155 (Print), 2374-1163 (Online) (doi:https://doi.org/10.12691/ajfn-6-2-3)

9. Apolot, M.G., Ssozi, J., Namutebi, A., Masanza, M., Kizito, E., Rees, D. and Acham, H. (2018) Changes in sensory and quality characteristics of S. Aethiopicum (Shum) and A. Lividus (Linn) leafy vegetables along the supply chain. American Journal of Food Science and Technology, 6 (4). pp. 161-166. ISSN 2333-4827 (Print), 2333-4835 (Online) (doi:https://doi.org/10.12691/ajfst-6-4-5)

10. Sekulya, S., Nandutu, A., Namutebi, A, Ssozi, J, Masanza, M, Jagwe, J.N., Kasharu, A., Rees, D., Kizito, E.B. and Acham, H (2018) Effect of post-harvest handling practices, storage technologies and packaging material on post-harvest quality and antioxidant potential of Solanum Aethiopicum (Shum) leafy vegetable. American Journal of Food Science and Technology, 6 (4). pp. 167-180. ISSN 2333-4827 (Print), 2333-4835 (Online) (doi:https://doi.org/10.12691/ajfst-6-4-6)

11. Sekulya, S., Masawi, A., Namutebi, A., Ssozi, J., Masanza, M., Kabod, B., Jagwe, J.N., Kasharu, A., Rees, D. and Kizito, E.B. (2018) Antioxidant potential of the farmer preferred selections of Solanum aethiopicum vegetable consumed in central Uganda. European Journal of Biological Research, 8. pp. 26-33. ISSN 2449-8955 (Online) (doi:https://doi.org/10.5281/zenodo.1195552)

12. Glowacz, M., and Rees, D. (2016) Exposure to ozone reduces postharvest quality loss in red and green chilli peppers. Food Chemistry, 210. pp. 305-310. ISSN 0308-8146 (doi:1016/j.foodchem.2016.04.119)

13. Glowacz, M., and Rees, D. (2016) Using jasmonates and salicylates to reduce losses within the fruit supply chain. European Food Research and Technology, 242 (2). pp. 143-156. ISSN 1438-2377 (Print), 1438-2385 (Online) (doi:1007/s00217-015-2527-6)

14. Glowacz, M., Colgan, R. and Rees, D. (2015). The use of ozone to extend the shelf-life and maintain quality of fresh produce (Review). Journal of the Science of Food and Agriculture, 95. Pp. 662-671

15. Glowacz, M. Colgan, R., Rees, D. (2015). Influence of continuous exposure to gaseous ozone on the quality of red bell peppers, cucumbers and zucchini. Postharvest Biology and Technology, 99, 1-8.

16. Macaulay B.B., and Rees, D. (2014) Bioremediation of oil spills: a review of challenges for research advancement. Annals of Environmental Science. 8: 9-37.

17. Cheema, M.U.A., Rees, D.,Colgan, R.J., Taylor, M. and Westby, A. (2013) The effect of ethylene, 1-MCP and AVG on sprouting in sweetpotato roots. Postharvest Biology and Technology 85: 89-93

18. Rees,D. van Oirschot, Q.E.A. and Aked, J. (2008) The role of carbohydrates in wound-healing of sweetpotato roots at low humidity. Postharvest Biology and Technology  50:79-86

19. van Oirschot, Q.E.A., Rees, D., Aked, J. and Kihurani, A (2006) Sweetpotato cultivars differ in efficiency of wound healing. Postharvest Biology and Technology 42: 65-74

20. Tomlins, K.I, Rwiza, E., Nyango, A., Amour, R., Ngendello, T., Kapinga, R., Rees, D., and Jolliffe, F. (2004) The use of sensory evaluation and consumer acceptability for the selection of sweetpotato cultivars in East Africa. Journal of the Science of Food and Agriculture.  84: 791-799

21. van Oirschot , Q.E.A, Rees, D., and Aked, J. (2004) Sensory characteristics of five sweet potato cultivars and their changes during storage under tropical conditions. Food Quality and Preference. 14, 673-680

22. Rees, D., van Oirschot, Q.E.A., Amour, R., Rwiza, E., Kapinga, R., and Carey T. (2003) Cultivar variation in keeping quality of sweetpotatoes. Postharvest Biology and Technology 28: 313-325

23. Stathers, T.E., Rees, D., Kabi, S., Mbilinyi, L, Smit, N, Kiozya, H., Jeremiah, S., Nyango, A., and Jeffries, D (2003) Sweetpotato infestation by Cylas in East Africa: I. Cultivar differences in field infestation and the role of plant factors. International Journal of Pest Management, 49: 131-140

24.  Stathers, T.E., Rees, D., Nyango, A., Kiozya, H., Mbilinyi, L, Jeremiah, S., Kabi, S., and Smit, N (2003) Sweetpotato infestation by Cylas spp. in East Africa: II. Investigating the role of root characteristics. International Journal of Pest Management, 49: 141-146

25.  Rees, D., Kapinga, R., Mtunda, K., Chilosa, D., Rwiza, E., Kilima, M., Kiozya, H. and Munisi, R. (2001).  Effect of damage on market value and shelf-life of sweetpotato in urban markets of Tanzania  Trop. Sci. 41: 142-150

26.  Agona, J.A., Nahdy, S.M., Giga, D.P. and Rees, D. (1999)  A visual scale of loss assessment for dried sweet potato chips due to Araecerus fasciculatus  Degeer (Coleoptera: Anthribidae) infestation on-farm.  Uganda Journal of Agricultural Sciences, 4:  1-5

27. Fischer, R.A., Rees, D., Sayre, K., Lu, Z.-M, Condon, A.G. and Larque-Saavedra, A. (1998) Wheat yield progress associated with stomatal conductance, photosynthetic rate and cooler canopies. Crop Sci. 38: 1467-1475

28. Rees, D., Horton, P. and Schreiber, U. (1993) The relationship between photosystem II intrinsic quantum yield and millisecond luminescence in thylakoids. Res. 37, 131-138

29. Cleland, R.E., Rees, D. and Horton, P. (1992) Light induced fluorescence quenching and loss of photochemistry in chromatophores of photosynthetic purple bacteria. Photochem. Photobiol. B: Biol., 13, 253-265

30. Rees, D., Lee, C.B., Gilmour, D.J. and Horton, P. (1992) Mechanisms for controlling balance between light input and utilisation in the salt tolerant alga Dunaliella C9AA. Res. 32, 181-191

31. Soma, M.R., Mims, M.P., Chari, M.V., Rees, D. and Morrisett, J.D. (1992) Triglyceride metabolism in 3T3-LI cells. An in vivo 13C NMR study. Biol. Chem. 267, 11168-11175

32. Ruban, A.V., Rees, D., Pascal, A.A. and Horton, P. (1992) Mechanism of delta-pH-dependent dissipation of absorbed excitation energy by photosynthetic membranes.II. The relationship between LHCII aggregation in vitro and qE in isolated thylakoids. Biochim. Biophys. Acta 1102, 39-44

33. Rees, D., Noctor, G., Ruban, A.V., Crofts, J., Young, A. and Horton, P. (1992) pH dependent chlorophyll fluorescence quenching in spinach thylakoids from light treated or dark adapted leaves. Photosynth Res. 31, 11-19

34. Noctor, G., Rees, D., Young, A. and Horton, P. (1991) The relationship between zeaxanthin, energy-dependent quenching of chlorophyll fluorescence and transthylakoid pH gradient in isolated chloroplasts. Biochim. Biophys. Acta 1057, 320-330

35. Horton, P., Ruban, A.V., Rees, D., Pascal, A.A., Noctor, G. and Young, A.J. (1991) Control of the light-harvesting function of chloroplast membranes by aggregation of the LHCII chlorophyll-protein complex. FEBS Lett. 292, 1-2

36. Ruban, A.V., Rees, D., Noctor, G.D., Young, A. and Horton, P. (1991) Long wavelength chlorophyll species are associated with amplification of high-energy-state excitation quenching in higher plants. Biochim. Biophys. Acta 1059, 355-360

37. Rees, D., Noctor, G. and Horton, P. (1990) The effect ofhigh-energy-state excitation quenching on maximum and dark level chlorophyll fluorescence yield. Photosynth. Res. 25, 199-211

38. Rees, D. and Horton, P. (1990) The mechanisms of changes in photosystem 2 efficiency in spinach thylakoids. Biochim. Biophys. Acta 1016, 219-227

39. Lee, C.B., Rees, D. and Horton, P. (1990) Non-photochemical quenching of chlorophyll fluorescence in the green alga Dunaliella. Photosynth. Res. 24, 167-173

40. Horton, P., Crofts, J., Gordon, S., Oxborough, K., Rees, D. and Scholes, J.D. (1989) Regulation of photosystem II by metabolic and environmental factors. Phil. Trans. R. Soc. Lond. B 323, 269-279

41. Rees, D., Young, A., Noctor, G., Britton, G. and Horton, P; (1989) Enhancement of the delta-pH dependent dissipation of excitation energy in spinach chloroplasts by light activation: correlation with the synthesis of zeaxanthin. FEBS Lett. 256, 85-90

42. Rees, D., Smith, M.B., Harley, J. and Radda, G.K. (1989) In vivo functioning of creatine phosphokinase in human forearm muscle studied by 31-P NMR saturation transfer. Nuclear Magnetic Resonance in Medicine 9, 39-52

43. Mitsumori, F., Rees, D., Brindle, K.M., Radda, G.K. and Campbell, I.D. (1988) 31-P NMR saturation transfer studies of aerobic Escherichia coli Biochim. Biophys. Acta 969, 185-193

44. Hasthorpe, S., Carver, J.A., Rees, D. and Campbell, I.D. (1988) Metabolic effects of interleukin 3 in 32D C123 cells analyzed by NMR. Cell Mem. Physiol.

45. Horton, P., Oxborough, K., Rees, D. and Scholes, J.D. (1988) Regulation of the photochemical efficiency of photosystem 2: Consequences for the light response of field photosynthesis. Plant Physiol. Biochem. 26, 453-460

46. Horton, P., Crofts, J., Oxborough, K., Rees, D. and Scholes, J.D. (1988) Regulation of the yield of chlorophyll fluorescence and the photochemical efficiency of photosystem 2. Proc R. Soc

My research focuses on optimising handling and storage of perishable produce to reduce food loss and waste. This includes the development and testing of new technologies and sustainable packaging.

I am particularly interested in technologies that are able to monitor the response of fresh produce to the storage and handling environment in situ, so that this information can be used to optimise that environment. As an example I provided scientific support for the development of the SafePod technology which uses respiratory characteristics of fruit in store to pick up stress responses and therefore allow optimisation of atmospheric composition for Controlled Atmosphere storage. This technology is now used in many countries of the world for apple storage. I am currently working on using a similar approach to improve potato store management. I have also worked on the potential for monitoring fluorescence from chlorophylls in green photosynthetic tissues as an indicator of produce health and shelf-life potential.  I am working with industry to develop the use of gaseous ozone for produce decontamination with no residues.

Lecturer on Postharvest Technology of Fruit and Vegetables for the Masters Programmes Food Safety and Quality Management, Sustainable Agriculture.

NERC: 2021-2023 Reduced plastic packaging and food waste through product innovation simulation. P-I for NRI. Partners: City (Lead), UoSheffleld, UoKent, WRAP. £738K

This project used modelling of the behaviour of different types of UK domestic households to predict the impact of food packaging design on both food and packaging waste. NRI’s role was to obtain data on the shelf-life of key fresh commodities for different packaging and storage scenarios.  The output of the project is a tool that can be used by the food industry to help determine the best packaging solutions that not only reduce packaging pollution, but minimise food waste.

Innovate SMART: 2020 O3Preserve: evaluating the potential for ozone flushing to extend shelf-life of strawberries. P-I for UoG. Partners: Ozone Technologies Ltd (Lead) £110K

Gaseous ozone is a powerful antimicrobial agent, but with its short shelf-life, rapidly breaks down leaving no chemical residues. This proof of concept project tested the concept of injecting ozone into retail packs of strawberries and demonstrated an extension of shelf-life. Funding is being sought to take this technology to commercial stage.

Newton: 2018 – 2020 BioFreshPak:Low cost film to reduce losses in the Indian fresh produce supply chain. PI for UoG. Partners: Nextek (Lead), Solutions4Plastics, Brunel University + 5 Indian collaborating organisations, £1.2M

This project tested the concept of using cassava starch to reduce the cost of compostable films for preserving fresh produce through the supply chain in India. The project successfully demonstrated the film manufacture, compostability and efficacy in shelf-life extension of a range of produce marketed domestically in Punjab, India.  Some of the findings are contributing to a new project, Nextloopp, also led by Nextek which seeks to develop a demonstration at commercial scale of recycling of ppolypropylene plastic packaging.

Innovate: 2015 – 2018 SafePod: New technology for intelligent control of fresh produce storage. Project Manager/ PI for UoG. Partners: SCS Ltd (Lead), AC Goathams, Avalon, Sainsbury’s. £860K

This project involved the development of the SafePod; a chamber that can be placed within a commercial apple controlled atmosphere store in order to monitor the metabolic status of the fruit. By detecting when the fruit is stressed, this enables the storage environment to be optimised. Furthermore, by monitoring changes in respiration rate through the storage season, it is possible to predict when the fruit has reached the end of its storage life and should be removed for marketing.

This technology is now being used by apple growers in the UK and in North America.

The concept of monitoring metabolic status in storage using SafePod is now being tested for other commodities, including potato.

BBSRC-HAPI: 2013–2016 Controlling dormancy and sprouting in potato and onion. CoI for UoG Partners: James Hutton Institute (Lead), Imperial College, Cranfield University) £640K

This project sought to unravel the genetic and molecular processes underlying the very important traits of tuber and bulb dormancy in potato and onion respectively.

Potato and onion production relies on industrial-scale storage to ensure year-round availability, for both fresh and processing sectors. Multiple strategies are used to extend dormancy and minimise sprouting, including low temperature storage and/or the application of sprout suppressant chemicals. Key sprout suppressant chemicals have been withdrawn recently, so that there is an urgent need to develop new storage strategies for potato and onion.

The project used phenotypic and genotypic analysis of the progeny of a cross between two diploid potato lines. NRI provided the potato storage environments and undertook the trials to enable phenotypic observations and sampling for genotypic analysis.

Project Outputs:

An updated unified model for hormonal dormancy control for potato was produced (also relevant to onion).

• Genome locations (QTLs) were identified associated with tuber dormancy and sprout growth. This could potentially lead to markers for tuber dormancy/sprouting for use in breeding
• Candidate genes involved in dormancy control were identified. Transgenic lines for functional validation and further expression work have been produced for one gene (TERMINAL FLOWER 1/CENTRORADIALIS).
• Profiles of gene expression, hormone concentrations, key metabolites and respiration through progression of dormancy, dormancy break and sprout growth were obtained for both potato and onion.

Joint lead of the Produce Quality Centre