According to Emilia Nordlund, Research Team Leader at VTT Technical Research Centre of Finland, plant-based food innovations could help address big global problems, such as climate change and environmental sustainability, as well as public health concerns.
“Our main purpose is to bring together people, business, science and technology to solve the world’s biggest challenges and to create sustainable growth,” she said in a recent VTT webinar. “…Our task is to advance the utilisation and commercialisation of technology.”
In order to do that, researchers at VTT are working on new textures and functionalities for plant-based foods, thereby expanding the market for them. Rising interest in flexitarian dietary patterns has helped give these products a boost in recent years, contributing to the development of new meat and dairy alternatives in particular. But looking to emulate the taste, texture and nutritional content of meat and dairy with plant-based ingredients raises many challenges.
In spoonable yoghurt alternatives, for instance, protein does not contribute to gel formation in the same way as dairy protein, meaning that starch and other components play a more important role. Plant-derived ingredients also have lower solubility and lower protein content, potentially leading to a less nutritious product with poor sensory quality.
“On the other hand, if we apply protein concentrates or protein isolates, we can increase the ability of the proteins to form a network and gel in the plant-based alternatives,” said Nordlund. “Of course we can actually make use of the other components present in the plant-based raw materials as texturizing components and also as health-promoting ingredients if we consider, for instance, dietary fibres. Then we can apply different functionalisation and processing strategies to improve the quality of the plant-based spoonable products.”
She gave examples of heat-induced improvements in gel strength using enzymes, such as phytase used with rice bran and rapeseed press cake. The gelling was also increased with the addition of calcium. But expectations do not always reflect reality. In pea dispersions, the researchers found phytase actually decreased the viscosity, while in faba bean dispersions, it increased it – and calcium plays a role too.
“Based on this data, it’s very important to know your raw materials and all the components present there,” she said. “We need to optimise the processing conditions – for instance, in the spoonable models – based on the raw materials and what is really happening. This is ongoing work, so we still need to try to understand a bit more these complex matrices.”
Enzymes can also help remove FODMAP components in products based on legumes like peas and beans. FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are short-chain carbohydrates that can cause intestinal discomfort in some consumers, and many legumes are high in FODMAP components.
“That’s why we tested enzyme-aided removal of galacto-oligosaccharides in pea and faba bean raw materials,” Nordlund said. “…Based on the enzyme process we applied, we were happy to see that the enzymes were effective.”
She added that the enzymatic treatments also did not affect the products’ texture.
Other VTT researchers have been looking at how to optimise the use of plant proteins in meat alternatives.
Research Professor Nesli Sözer explained that extrusion processing had been used since the 1960s to create a meat-like structure, but mainly this has been dry extrusion, often requires rehydration prior to consumption.
“These products are typically used as meat extenders and ground meat substitutes,” she said. “However, they failed to mimic the appearance, and there is a texture problem…From that perspective, high moisture extrusion is quite promising and, compared to dry extrusion, it’s a new technology that can enable us to produce fibrous structure that mimics meat-like textures in a better way than the dry extrusion.”
What else affects texture?
From a technical perspective, high moisture extrusion has several major effects on plant proteins, altering the texture and flavour through starch gelatinisation, fibre solubilisation, and by denaturing the protein, for example. VTT researchers have explored how these effects vary depending on the plant protein ingredient.
“It is very important to understand the relationship between the ingredient properties and extruder responses, which dictates the product texture,” said Sözer. “…We end up getting quite distinct structural features.”
If a product developer is looking for a fibrous, meat-like texture, her team found that rice protein concentrate was among the most challenging of plant-based ingredients, while pea protein isolate was easier to optimise via wet extrusion. Adding dietary fibre or pectin could also help to improve the texture and structure of some products, as could using fermentation, shifting the pH or changing the temperature at which the ingredients are extruded.
“You really have to know your raw materials when you are starting to develop your process,” concluded Nordlund. “…You really have to deep-dive to a molecular level to understand what goes on there.”