Flavoring high protein products is problematic initially and then over the shelf life of a product due to interactions that occur between the two food components. The interactions are multifaceted. There has been a lot of research over four decades studying the “temporary” interactions between flavor compounds and various proteins but very little work has been done on a more permanent interaction: covalent bonding. This research is focused on studying the various covalent bonds that may be formed between the side chains and terminal amino acids of food proteins (plant and dairy based), and reactive aroma compounds which will alter the flavor profile in an irreversible manner.<br/><br/>The study takes the approach of monitoring the extent and rate of flavor reactions with intact proteins using UPLC-QTOF MS for increase in molecular weight (Protein+ flavor compound/s). This study also investigates interactions of different flavor molecules with intact proteins under different conditions as the type and rate of interaction are expected to vary with functional groups of the flavor compounds, and their concentrations as well as amino acid composition of the protein, pH, water activity, and storage temperature. A proteomics approach is taken to find the post translational modification site on the protein by each flavor molecule.<br/>The results of this study will help in understanding the conditions at which flavor compounds will covalently bond with a protein. The end goal is to help the food industry develop flavor systems to flavor proteins that perform better.<br/>Results have confirmed that irreversible covalent bonds are formed between flavor compounds and protein. Single variant Beta-lactoglobulin (BLG) was chosen as the model protein and five different aldehydes as flavoring compounds (F). The protein samples (1% in water) were maintained at pH 6.7, held at 25°C with added flavor (12ul) and sampled at 6 different reaction times. The results have shown new spectra that indicated the formation of Schiff bases and Michael addition products. The new masses observed after flavor reaction correspond to the different number of flavor molecules that have reacted with the proteins: BLG + one F, BLG + two F and so on. The reaction rate increased over time leading to the disappearance of the pure protein peak with only protein:flavor adduct peaks being present.

Plant and dairy protein and their covalent interactions with flavor

2019 Fall National Meeting

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