THE EFFECT OF EATING ON AROMA RELEASE FROM STRAWBERRIES

The aroma of strawberries was sampled directly from the expired air of people eating strawberries and by a headspace method which had been designed to mimic maceration in the mouth. Comparison of the aroma profiles showed that, using the modified headspace technique, it was possible to produce headspace profiles for the esters, very similar to the profile observed in the nosespace. The C6 aldehydes hexanal and (E)-2-hexenal were present at higher amounts in the headspace than the nosespace. The amounts of these volatiles in the headspace of strawberries increased as the homogenisation period increased. Reducing the duration of homogenisation before headspace collection resulted in lower amounts of C6 aldehydes and headspace profiles virtually identical to the nosespace profiles. The rate of release of aroma volatiles from strawberries during eating was also investigated. This demonstrated that the maximum concentration of aroma volatiles occurred at the point of swallowing. Prior to this, volatile concentrations were 40-60% of the maximum level observed: this is likely to have been associated with swallowing the juice and saliva present in the mouth at this time, resulting in transfer of volatiles to the nasal cavity. The volatiles which persisted the longest in the nosespace were the smaller esters, methyl acetate and ethyl acetate. This may be due to the differences in polarity between these compounds and other less-polar esters such as methyl butanoate.