Enzymatic and microbial solubilization of brewers' spent grain for sugar and phenolic compound extraction
Hakakari, Jaakko (2024-12-13)
Enzymatic and microbial solubilization of brewers' spent grain for sugar and phenolic compound extraction
(13.12.2024)
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
suljettu
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe20241219105101
https://urn.fi/URN:NBN:fi-fe20241219105101
Tiivistelmä
Brewer’s spent grain (BSG) is a nutritionally valuable by-product of brewing beer. BSG is rich in phenolic compounds, fibre and protein. Current methods of utilizing BSG range from animal feed to biofuel production. Issues with utilizing BSG in food production stem from how BSG spoils rapidly as it is a favourable growth medium for bacteria and fungi. Methods of sterilization prove costly and labour intensive, so immediate methods of processing are needed. Currently there are no in-house methods of gaining value from BSG within microbreweries.
The aim was to create an immediate method to utilize BSG within a microbrewery setting using bacteria and enzymes. By employing a method to release fermentable sugars and potential flavour-active phenolic compounds from BSG, these compounds can be reintroduced back into the brewing process. Onsite processing would rule out the need for heat treatment and cold storage. Fresh BSG was collected from local breweries, blended, and stored in water at room temperature. Multiple samples were collected in 30 ml batches with a variety of different lignocellulose-hydrolysing enzymes and a Lactiplantibacillus plantarum strain. Samples were incubated in 25 ° C for 20 hours before collecting the liquid fraction for analysis. For analysis, UHPLC-DAD is used to quantify phenolic acids, HPLC-MS/MS is used for phenolic acid identification and HPLC-ELSD is used to analyse the sugar content within the samples.
An analysis of the liquid fraction with UHPLC-DAD revealed an increase in ferulic acid and p-coumaric acid with samples treated with enzymes. An upcoming analysis of sugars within the samples is expected to show an increase in sugars produced by enzymes and a reduction in glucose within samples containing Lactiplantibacillus plantarum. The goal is to produce a method of extracting components like lactic acid, complex carbohydrates, and phenolic acids from BSG and reintroducing said components into the beermaking process.
The aim was to create an immediate method to utilize BSG within a microbrewery setting using bacteria and enzymes. By employing a method to release fermentable sugars and potential flavour-active phenolic compounds from BSG, these compounds can be reintroduced back into the brewing process. Onsite processing would rule out the need for heat treatment and cold storage. Fresh BSG was collected from local breweries, blended, and stored in water at room temperature. Multiple samples were collected in 30 ml batches with a variety of different lignocellulose-hydrolysing enzymes and a Lactiplantibacillus plantarum strain. Samples were incubated in 25 ° C for 20 hours before collecting the liquid fraction for analysis. For analysis, UHPLC-DAD is used to quantify phenolic acids, HPLC-MS/MS is used for phenolic acid identification and HPLC-ELSD is used to analyse the sugar content within the samples.
An analysis of the liquid fraction with UHPLC-DAD revealed an increase in ferulic acid and p-coumaric acid with samples treated with enzymes. An upcoming analysis of sugars within the samples is expected to show an increase in sugars produced by enzymes and a reduction in glucose within samples containing Lactiplantibacillus plantarum. The goal is to produce a method of extracting components like lactic acid, complex carbohydrates, and phenolic acids from BSG and reintroducing said components into the beermaking process.