Commercial on-line MS systems have been available for over 20 years, and their application to flavor research has been reviewed for SIFT-MS¹ and PTR-MS² but not for APCI-MS. Here, we present some of the pioneering applications developed at the University of Nottingham, UK. These include the initial studies on the patterns of aroma release from foods during eating, which led to the conclusion that the retronasal aroma profile varied over the time of eating and was very different from the flavor composition of the food and the headspace measured above the food³. Efforts to reduce sugar, and fat in foods, while maintaining the original flavor, initiated studies on the connection between the physicochemical factors of the food matrix and aroma release⁴. In response to an enquiry about the flavor-fade in chewing gum, significant taste-aroma interactions between sweetness and minty odours were discovered⁵. To measure the aroma profile in fresh tomatoes when eaten, a rapid technique was developed to mimic the disruption of the tomato tissue, while simultaneously measuring the pre-formed aroma compounds as well as the formation of the enzymically-generated aroma compounds⁶. Combining APCI-MS with physiological methods showed the relationship between chewing, breathing and swallowing during the eating of foods⁷. The effect of sugar crystallisation on the rate of the Maillard reaction was monitored using FT-IR and APCI-MS⁸, while the effect of water content on the first few steps in the Maillard reaction showed the reaction flux was highly dependent on water levels⁹. Lastly, the dynamic binding of aromas to Odour Binding Protein (OBP) in the nasal passages was used an in vitro system to study competitive binding of aromas to OBP¹⁰.

Andrew Taylor

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