Modelling ethylene flux in kiwifruit boxes - PhD Studentship

PhD Studentship - Modelling ethylene flux in kiwifruit boxes

The export of New Zealand kiwifruit is valued in excess of NZ$1.6 billion per annum, and is the most important fresh produce industry in the country. A key component of the success of this industry is the development of a strong brand presence (Zespri™), which amongst many things, aims to differentiate New Zealand kiwifruit as of superior quality to that of the competitors. In order to deliver this superior quality consistently, monitoring and manipulation of the environmental conditions during the storage and transport phases of the kiwifruit supply chain play a pivotal role. It is well known that the concentration of ethylene immediately adjacent to the fruit influence fruit physiology and subsequently deterioration during storage. Current practice is to monitor and control ethylene concentration in the storage room and make corrective action when increase to concentrations is detected. However, the amount of ethylene to which a fruit is exposed to may be very different from that of the coolroom environment, as the packaging of the kiwifruit within the supply chain acts as a barrier between the immediately adjacent and external environmental conditions and as such play an important role in regulating the conditions experienced by the kiwifruit.

Massey University's Centre for Postharvest and Refrigeration Research seeks a candidate for a PhD studentships fully funded by Zespri International Ltd. that aims to contribute to the knowledge of ethylene flux in kiwifruit boxes. Massey University has a substantial history of providing fruit physiology and engineering research to New Zealands fresh produce sector. The successful candidates will join a group of 5 researchers and 11 postgraduate students working in the postharvest arena.

In order to be eligible applicants must:
• hold an appropriate prerequisite degree(s).
• meet the eligibility requirements for PhD study at Massey University.
• maintain the progress and behaviour expected of a PhD candidate.
Interested candidates that are currently completing a degree, and will be able to begin the project prior to the completion of 2018 can apply.

Project Description
During storage, fruit produce emit and adsorb volatile components (such as ethylene and methanol) that may induce fruit responses and/or be used as signals by sophisticated sensors to determine fruit status. While the flux of carbon dioxide, oxygen and water within some fruit (in particular pears and apples) and its immediate environment is a well established field of postharvest science, the flux of ethylene and other volatile compounds within commercial fruit packaging systems is still poorly understood. In particular, there is a substantial lack of information with respect to volatile production rates from fruit and their dependency on the fruit status (temperature, maturity, rots, and damage), ethylene adsorption rates (by both fruit and packaging materials) and transfer of volatiles through packaging (polyliner, cardboard and wooden) materials. This PhD project, aims at establishing the flux of ethylene in commercial kiwifruit packaging systems, and the subsequent establishment of a predictive model of the ethylene concentration within a commercial package as a function of fruit status (temperature, maturity, rots and damage). The model outcome will aid understanding of the parameters that influence the magnitude and variability of ethylene movement and accumulation within a package, and as such be a useful tool for managing in package ethylene concentrations, and designing/interpreting sensor based systems that target the measurement of ethylene. Suitable candidates for this project may come from plant physiology, horticulture, transfer process modelling or process engineering backgrounds.

Applications should include an introductory letter, a formal curriculum vitae and a 1 page essay on "Gas movement in food packaging systems".

Stipend: NZ$27,500 (tax-free) + university fees ($8500) for 3 years + $7500 travel assist package (for attending a conference and overseas lab visit).
Project Supervisors: Dr Sunny George Gwanpua, Dr Jamal Olatunji, and Prof Andrew East
Location: Centre for Postharvest and Refrigeration Research, Massey University, Palmerston North, New Zealand
Start date: Prior to end of 2018
Applications due by: July 27th 2018
All applications should be sent to Dr Sunny George Gwanpua. Email.

Palmerston North (New Zealand)