Less-pure forms of protein retain functionality, finds protein study

28 Aug 2017 --- Proteins extracted from potatoes, blood plasma and peas retain their functionality, even in less-pure forms. In fact, sometimes their functionality is improved. Researchers from Wageningen University & Research, NIZO and TNO came to this conclusion after a two-year study – a Strategic Innovation Project (SIP) – carried out by the Protein Competence Center. The results provide manufacturers with new approaches to improve the sustainability of protein production.

Whether it’s cappuccino and desserts or bread and mayonnaise, there are few foods that don’t need proteins. They provide nutritional value, give lightness to products and as an emulsifier keep fats and water together. The functionality of proteins can be quickly lost. For example, they can aggregate when mixed with other proteins, or their structure changes with the degree of acidity. Therefore manufacturers purify the proteins from plant and animal sources as much as possible – a step that has relatively high water and energy costs. "But our research shows that such intensive purification is not necessary for all applications," says Marcel Meinders, senior researcher at Wageningen Food & Biobased Research and the project leader.

The research project Functionality of protein-fat mixtures in complex matrices (2014-2016) offers clarification here. "The goal was to predict the functionality of protein isolates in which several other ingredients, such as fats and carbohydrates, were also present," explains Meinders. "The emphasis was on proteins from potatoes, blood plasma and peas." Researchers from Wageningen University & Research, TNO and NIZO worked closely together in the SIP project. "A unique collaboration to which each institute brought its own skillset and expertise, allowing us to paint a complete picture." Diverse technologies were used and combined for example to measure surface properties and solubility. 

In many cases, the proteins were found to retain their functionality very well in less purified forms. Sometimes their functionality even improved. 

For Darling Ingredients, one of the industrial partners in the project, the results of the project confirmed their suspicions. "The water solubility and gel-forming ability of blood proteins decrease above a certain temperature or humidity," says Fred Beekmans, director R&D and Quality. "For the first time, we are now able to measure this under controlled conditions." The company intends to use these insights to improve quality preservation during transport to distant lands.

Hugo Streekstra, principal scientist at DSM, is enthusiastic about the set of measurement methods the project has delivered. "With good functional testing you can, as a manufacturer, determine what degree of purification is good enough or, perhaps, better," he says. The multinational has already applied the methods in their own research for, amongst others, the extraction of proteins from rapeseed. 

In 2017, a request for a follow-up protein-functionality project was submitted, with DSM and a number of new industrial partners within the Protein Competence Center. Among other issues, the project will investigate aggregation dynamics, synergies and digestibility of proteins in less purified protein mixtures.

In an article to be published in the September 2017 issue of The World of Food Ingredients, Harry Wichers and Jurriaan Mes of Wageningen Food & Biobased Research in Wageningen, The Netherlands, note how studying the digestibility and techno-functional properties of dietary protein is of paramount importance. "The tools for the science-based search for alternative sources are available, and up and running. Wageningen University & Research has the toolbox to study protein digestion, both in vitro (in high- and medium throughput systems) and in human trial settings," the authors note.