Coming up with the research question – a redirection
The start of my application for the Laidlaw scholarship began with a flyer lying on a table in the corner outside the chemical café. It seemed intriguing - an opportunity to conduct a self-proposed project, fully funded, with support from the university. At first, my proposed project was related to pH changes within citrus fruits during spoilage, which originated from an observation at home. I wondered why certain pomelos tasted “off” even though they looked fine on the outside. Here came the first hurdle - how feasible and how impactful would this research be?
Upon further investigation and discussion with my supervisor, Dr Jia Li, we agreed that a shift of focus was necessary. Practically, citrus skins are highly effective at protecting the fruit, so experiments on spoilage could yield little meaningful data. A new direction emerged while conducting the first literature review - ripening. Spoilage consists of two different mechanisms: microbial and chemical. Ripening, or rather over-ripening of fruit, falls under chemical spoilage. In local supermarkets, many fruits are labelled as “ripen-at-home,” but how different would these “ripened-at-home” fruits be compared to the same fruits ripened via other methods? This seemed a fruitful direction, particularly because gaps in current research exist. Geographically, sample collection was also feasible, as there were orchards nearby producing the relevant fruits.
Planning the experiment
With a clearer research direction, I needed to decide how to conduct my experiment. First, I identified methods of ripening and ways to collect samples. The most common method uses ethylene, a plant hormone, known for ripening bananas industrially. I decided to replicate this industrial method on a small scale. Next, I needed controls and comparisons, so I chose home-ripening, ethylene ripening and on-tree ripening, which nicely fit into the six week timeframe.
Another consideration was which fruits to use. Ethylene only affects climacteric fruits, which limited my options. Fortunately, local farms had apples, plums and pears available, all of which are climacteric fruits. A challenge then arose: industrial ripening chambers are large and expensive, so I needed to create a small-scale version. With guidance from the Department of Chemistry, I connected with Charlie, a PhD student in Professor Britovsek’s group, who helped me with designing a functional ripening chamber. This process taught me a key lesson: never be intimidated to ask for help.
Implementing the experiment (so far)
The first step was securing a source of ethylene and preparing the makeshift ripening chamber. Ethylene proved hazardous without proper facilities, but Professor Britovsek facilitated access. After discussing chamber criteria with Charlie: clear for observation, airtight to trap ethylene, and moisture-absorbing to prevent microbial rotting. After realising commercially available containers that fit the criteria didn’t really exist, I decided to make my own ripening chamber. I sourced transparent Ikea storage boxes, drilled holes for Swagelok fittings, and used butyl tape for sealing. Surprisingly, airproofing was more challenging than introducing ethylene at 100–150 ppm, but we persevered. While working in the lab, I observed how the chemists there designed and set up their experiments, which were very complicated and required producing custom equipment, which was very impressive. “…At this point, I’m more of a chemical engineer than a chemist…” he joked.
The second step was sample collection. Nicola from Home Cottage Farm kindly allowed me to pick unripe fruit. I learnt that their fruits were grown naturally with minimal human intervention, and factors such as rainfall directly affected fruit size. Collecting samples at the orchard was an enriching experience, connecting me with the source of my experiments and allowing comparisons with commercially ripened fruit.
Once collected, the ethylene and home-ripened samples were sealed in the containers. Introducing ethylene turned out to be the easiest part of the experiment. Transporting the six large containers from the White City chemistry lab to the Hammersmith Hospital biology lab was a highlight: lugging containers, Ubering, climbing stairs, and navigating tunnels to finally store them on the 10th floor of the Commonwealth building was labor-intensive, but immensely satisfying. Seeing the large stack of boxes, I felt proud of what I had managed to accomplish.
Processing the samples for NMR
Preparing samples for NMR involved two forms: freshly ripened fruit and freeze-dried samples. During processing, I underestimated the workload: separating flesh and skin, weighing aliquots for lysis, and freeze-drying hundreds of samples was far more time-consuming than anticipated. Yet, this repetitive work taught me efficiency and refinement of techniques—practice truly makes perfect.
I learnt a lot through mistakes and incidents in this process. During freeze-drying, some samples bubbled, highlighting the importance of properly freezing samples before vacuuming. Eppendorf caps occasionally “exploded” in the tissue-lyser, teaching me to use my newfound favourite lab essential - parafilm - and to check lids thoroughly. An unbalanced centrifuge reinforced the need to adapt patterns to maintain symmetry. I also developed unconventional but effective techniques for cutting and skinning fruits, using surgical blades and supermarket peelers. Funnily enough, I have mastered cutting fruit flesh and peel weighing between 0.2–0.3 g, due to the large number of samples.
I am immensely grateful to Kaourta and Xuan for helping acquire liquid nitrogen, walking ten flights of stairs to do so, and to Jiao, a visiting researcher, for guiding my bead-beating and freeze-drying techniques. Initially, I questioned whether liquid nitrogen was necessary for freeze-drying, but after consulting Dr Li and a colleague, we determined that freezing samples in a –80°C freezer was sufficient, saving effort without compromising quality.
pH measurements were crucial, as different conditions affect compound interactions. Here, I faced a major “jumpscare”: breaking my very expensive glass pH electrode. That tiny snapping sound initially felt catastrophic, and I panicked about informing my supervisor. Thankfully, Laidlaw funding helped replace the electrode, but the incident reinforced lessons in responsibility, careful handling, and learning from mistakes.
Reflections and ongoing progress
Overall, this project has been an incredible learning experience. Beyond technical skills, I gained insight into the researcher’s mindset: patience, resilience, problem-solving, and creativity. I was excited to apply skills I learned at university in these labs and get a taste of what being a researcher is like, especially after observing other researchers and talking with them, which I thoroughly enjoyed. Every challenge, from chamber design to sample processing, reinforced the importance of planning, iteration, and learning from errors.
Looking forward, I am eager to collect my final ripe samples and complete NMR analysis. Each stage so far has shown the rewards of persistence, attention to detail, and collaboration. Mistakes, while sometimes frustrating, have been invaluable learning opportunities. The combination of practical experimentation, hands-on lab experience, and interactions with other researchers has solidified my interest in pursuing experimental science further.