A team of researchers at the Norwegian University of Science and Technology (NTNU) has developed a technique to convert brewer’s spent grain (BSG) into protein-rich microcapsules.
The output from the research can be used to preserve fish oil, medical, and cosmetic ingredients.
BSG, the residue from beer and whisky production, is generally discarded or used in animal feed.
It is a by-product containing high levels of protein, particularly hydrophobic amino acids, which provide emulsifying and film-forming characteristics.
According to the NTNU, “there is a growing research interest in using such a valuable plant protein source [BSG] as a sustainable alternative to animal proteins in the industry”.
The NTNU study achieved the extraction of protein concentrates from BSG through an alkaline extraction process “with the aim of using them as wall material for microencapsulation of fish oil for the first time”.
“Given the hydrophobic nature and strong emulsifying/film-forming properties of BSG proteins, they can be a good candidate as wall material for fish oil microencapsulation and fortification of food products with health-beneficial omega-3 fatty acids,” according to the document published by the university.
Microencapsulation is a technology that involves enclosing active ingredients or substances within capsules to protect, control release, or enhance stability in various applications.
The research also analysed how precipitating agents and moderate heating impact the composition and properties of BSG proteins, using proteomics and bioinformatics for molecular and physicochemical assessment.
It found that substituting hydrochloric acid with citric acid as a precipitating agent, coupled with protein aggregation induced by pH changes, enhanced the oxidative stability of fish oil microcapsules.
The study concluded that BSG protein concentrates offer a sustainable solution for microencapsulation, with potential applications across the food, pharmaceutical, and cosmetics sectors.
It highlighted that upcycling brewing residues into higher-value products could effectively reduce food waste and aid in the development of functional foods.
