Effects of sucrose monopalmitate (P90), Tween 80 and modified starch on coffee aroma retention and release in coffee oil-based emulsions

Abstract

Despite the convenience and extended shelf life of instant coffee, its aroma profile is less desirable compared to freshly brewed coffee. The objective of this study was to evaluate the effects of sucrose monopalmitate (P90), modified starch (MS) and Tween 80 on coffee aroma retention and release in oil-in-water emulsion matrices (coffee oil as the flavor matrix) and upon spiking into instant coffee, with an aim to enrich instant coffee aroma. The volatile profiles of P90-, MS- and Tween 80-stabilized coffee emulsions before, after freeze-drying and upon spiking into instant coffee were characterized with HS-SPME-GC-MS/FID and compared. The extent of volatile retention and release varied with the type of emulsifiers and volatile classes. Aldehydes and phenolic compounds levels in P90-stabilized coffee emulsions were 40% and 30% significantly lower compared to the control while their levels in Tween 80-stabilized coffee emulsion were 8% and 38% lower compared to the control respectively. Phenolic compounds levels in MS-stabilized coffee emulsion were 13% significantly lower compared to the control. Volatile retention remained after freeze-drying for P90- and Tween 80-stabilized coffee emulsions where total volatile levels were 12% and 25% significantly lower compared to the controls, respectively. The total volatiles levels of instant coffees spiked with P90- and MS-stabilized coffee emulsions were higher compared to the blank and spiking with the controls. The trend was reversed when Tween 80-stabilized coffee emulsion was spiked. Therefore, P90- and MS-stabilized coffee emulsions exhibited some extent of controlled aroma release and could be utilized for instant coffee aroma enrichment.