Although switching to plant-based diets is urgently needed to mitigate climate change, a significant challenge in embracing meat alternatives is their dry and parched texture when they are consumed.
However, a team of scientists led by the University of Leeds has recently revolutionized the sensation of plant proteins, turning them from a thick and dry substance to one with a juicy and fat-like texture. Surprisingly, their only addition to the plant proteins is water.
The key to this transformation lies in the formation of plant protein microgels via a procedure named microgeletion. Initially dry and coarse, plant proteins are submerged in water and then heated. This heat exposure modifies the protein molecules’ structure, making them cluster to establish a gel-like interconnected network that entraps water around them.
Upon homogenization, this gel disintegrates into a microgel consisting of minuscule particles invisible to the naked eye. When subjected to pressure, as during eating, these microgels release water, leading to a texture similar to that of single cream.
“What we have done is converted the dry plant protein into a hydrated one, using the plant protein to form a spider-like web that holds the water around the plant protein,” explained senior author Anwesha Sarkar, a professor of Colloids and Surfaces at Leeds.
“This gives the much-needed hydration and juicy feel in the mouth. Plant-based protein microgels can be created without having to use any added chemicals or agents using a technique that is widely available and currently used in the food industry. The key ingredient is water.”
According to the scientists, the inherent dryness of plant proteins has long been a “key bottle neck for consumer acceptability.” With this new approach, they are optimistic about reigniting consumer interest in plant proteins. This could inspire a decrease in dependence on animal-based proteins, which is an essential shift to attain global climate change goals.
Remarkably, over half of the annual 18 billion tons of CO2 equivalent emanating from food production originates from rearing and processing animal products. Fortunately, these protein microgels will likely offer “a unique platform to design the next generation of healthy, palatable, and sustainable foods,” as the authors put it.
Although during their investigation the scientists had mathematically predicted the behavior of the microgels and felt confident about their methodology, concrete evidence emerged through atomic force microscopy visualizations at the Faculty of Engineering and Physical Sciences at Leeds. This intricate technique utilizes a diminutive probe to scan molecular surfaces and produce an image.
“Seeing the images from the atomic force microscope was a such as exciting moment for us. The visualizations revealed that the protein microgels were pretty much spherical and not aggregating or clumping together. We could see individually spaced plant protein microgels,” Sarkar said. “Our theoretical studies had said this is what would happen but there is nothing quite like seeing it for real.”
“This study reveals the ingenuity and depth of science involved in modern food technology, from the chemistry of proteins, the way food is sensed in the mouth to an understanding of tribology – the friction between materials and sensory cells in the mouth. Tackling the big questions in food science requires interdisciplinary science,” added co-author Melvin Holmes, an expert in Food Science and Nutrition at Leeds.
The lubricity of these microgels suggests potential diverse applications in the food industry, such as using them as substitutes for fats extracted from products in order to develop healthier food options.
“This is quite a remarkable finding. It is striking that without adding a drop of fat, the microgels resemble the lubricity of a 20 percent fat emulsion, which we are the first to report,” said lead author Ben Kew, a PhD student in Food Science and Nutrition at Leeds.
“Our experimental data supported by theoretical analyses also mean we could begin to use these plant protein microgels in foods where fat has to be removed to reformulate into healthier next generation plant protein food options,” he concluded.
The study is published in the journal Nature Communications.