Replacing fat in food without compromising sensory properties leads to PhD for UP student

Posted on May 22, 2020

You don’t have to sacrifice taste for less fat in your favourite mayonnaise, and Dr Joyce Agyei-Amponsah has proven it scientifically, earning a PhD in Food Science from the University of Pretoria (UP) in the process.

Dr Agyei-Amponsah was one of 11 000 UP students who graduated during a virtual ceremony in April.

Her research proved that fat replacers can be used to replace up to 80% of the sunflower oil in mayonnaise-type products without changing the smoothness, creaminess, melting, mouth coating and lubrication properties.

Asked how she felt about receiving her PhD, an elated Dr Agyei-Amponsah said, “I am excited to have attained the highest formal education I aspired to achieve on my career road map.

“On a bigger scale, findings from my research will help expand the frontiers of knowledge in producing reduced-fat foods to address the global challenge of obesity. I also got the opportunity to attend international conferences and to build and be part of a network of great scientists.”

Dr Agyei-Amponsah obtained her PhD under the supervision of Professor Naushad Emmambux and Professor Riëtte de Kock from UP’s Department of Consumer and Food Sciences. She currently works as a Senior Food Research Scientist at the Biotechnology and Nuclear Agriculture Research Institute of the Ghana Atomic Energy Commission.

Obesity and diseases related to it, including cancers, heart disease and diabetes, have become a global health issue. Dietary fat is one of the critical risk factors contributing to this problem. Reduction of the fat content of popular food products, without changing the desirable sensory properties provided by fat, is a challenge. In her PhD study, Dr Agyei-Amponsah used rheology (the science of the deformation and flow of matter), tribology (the science and engineering of interacting surfaces in relative motion), and sensory science (the science behind using the senses when eating) to study two novel fat replacers in mayonnaise-type foods.

She explained why she chose this specific research field. “After attaining my first degree in nutrition and food science, my interest to study the nature and principles of food processing grew. I became particularly interested in the area of product development, value addition, sensory evaluation and shelf-life extension of foods.

As a wife and mother of two, she had to make some sacrifices to complete her PhD. “My husband and my two lovely kids inspired me to fight on and not to give up. Being away from my young family for four years to pursue my PhD was the greatest challenge for me. I could not stop asking myself if it was the right decision or not. But I was somehow encouraged to do this for them.”

She also gave credit to her father for her academic success. “I come from a family that appreciates academics. My dad, now retired, was the chief technician at the Physics Department of the University of Ghana and I lived and grew up in a university community. I know it was a silent wish of my daddy for one of his daughters (he has only girls) to attain a PhD. He is a proud daddy,” Dr Agyei-Amponsah said.

Dr Agyei-Amponsah expressed her gratitude to the Organization for Women in Science for the Developing World (OWSD) for granting her a PhD fellowship and the DST/NRF Centre of Excellence in Research Food Security and the National Foundation (NRF) South Africa for funding her research.

- Author NAS

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