A new resource available for UW Hub partners: High-resolution metabolomic analysis of dairy products

A recent short-term, high-impact UW–Madison Dairy Innovation Hub project has developed a new analytical method to analyze dairy samples including milk, cheese, yogurt, and butter. David Lang and Chang Liu in the Bolling Research Group at the Department of Food Science at UW have developed methods and data processing tools to use high-resolution mass spectrometry for analysis of small-molecule metabolites across a wide range of dairy products. These analyses have been indexed in a “Dairy Databank” and can be used by UW Hub collaborators interested in understanding the composition of dairy products. 

Orbitrap Exploris 240 Mass Spectrometer with Liquid Chromatography (Courtesy ThermoFisher)

The key instrument used for the analysis is a high-resolution mass spectrometer coupled to liquid chromatography that was obtained by the Department of Food Science from a USDA equipment grant. The instrument can detect thousands of small molecules in dairy products by ionizing and fragmenting compounds to identify unique individual components. The sample preparation, instrument set-up, and analysis using this analytical technique can often be accomplished within a single workday and provides a unique chemical signature for a given product or sample.

The approach makes use of an open-source Milk Composition Database. Currently, the team has described more than 7,000 metabolites across an array of milks, yogurts, cheeses, butters, fermented milk products, and dairy powders. These unique signatures can help explain what makes specific dairy samples unique from each other. For example, the methods can be used to describe the unique metabolites that are formed during the aging of cheese or describing the differences between individual milks or yogurts. The initial data set revealed that Greek yogurt and skyr have abundant branched-chain hydroxy acids which helps to understand their potential health benefit.

There are many potential applications of this technology — from understanding the impact of the environment or farming practices on milk quality or investigating the impact of processing on composition of dairy products.

UW Hub collaborators are invited to use this resource, and can learn more by contacting David Lang or Dr. Bolling at https://bolling.foodsci.wisc.edu/mass-spectrometer/.

(left) Dr. Brad Bolling and Dr. Chang Liu with the instrument used for UHPLC-MS/MS analysis of dairy products.
(right) David Lang, Graduate Research Assistant, Bolling Research Group
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