Poster Presentation 25th Annual Lorne Proteomics Symposium 2020

Molecular profiling of fermented dairy products using mass spectral fingerprinting technologies (#113)

Evelyne Maes 1 , Fionnuala Murphy 1 , Ines Weissenbacher 1 , Erin Lee 1 , Hanh Nguyen 2 , Raise Ahmad 2 , Julie Dalziel 2 , Anita Grosvenor 1 , Alastair Ross 1 , Li Day 2 , Stefan Clerens 1
  1. AgResearch Limited, Lincoln, New Zealand
  2. AgResearch Limited, Palmerston North, New Zealand

The proteins in milk and dairy products are an important nutrient source for humans. Fermented milk products have long been a common way to consume milk across many cultures, and add flavour, functionality and nutrition. Fermentation of milk releases small peptides that lead to enhanced sensory properties and may also have health promoting bioactivities. The peptide and small molecule profiles of milk and its fermented products can reveal the different metabolic actions of diverse starter cultures and aid in the selection of optimal microbes for enhanced fermented milks.

In this study, we compared the molecular profiles of four dairy products: bovine milk (negative control), milk hydrolysate (positive control) and two milk products fermented using two different commercial starter cultures. Several mass spectrometry-based approaches were used to evaluate the difference in molecular expression between the four samples. Rapid evaporative ionisation mass spectrometry (REIMS) screening was used to determine the small molecule diversity of the samples. Next, the peptides and amino acids present in the samples were profiled using a fingerprint obtained by matrix-assisted laser desorption ionisation (MALDI) – time-of-flight (TOF). Combined, the small molecule and peptide fingerprints of the products function as a ‘molecular signature’ that can rapidly reveal 1) the molecular similarity of fermented products, 2) the effects of proteolysis and 3) the small molecule composition of the products. To identify the sequence of specific peptides released, and allow the prediction of bioactivity, a peptidomics approach was then used. Taken together, molecular fingerprinting was able to distinguish the effects of different starter cultures on proteolysis and subsequent peptide release in different milk products. With this suite of techniques, a rapid molecular profile of the influence of different starter cultures in the fermentation process can be obtained which can be applied to tailor new products and cultures.