Characterization of Royal Gala Apple Aroma Using Electronic Nose TechnologyPotential Maturity Indicator

Changes in aroma of apple harvested at four different maturities were measured at harvest and after short-term storage using electronic aroma sensors (“electronic nose”) and classical headspace/gas chromatography methods. Stored fruits were also evaluated by a trained sensory panel. Compared with headspace/gas chromatography, the electronic nose was found to be more sensitive (∼40 times) in terms of sample size. The sampling procedure for the electronic nose was much less complex. Using discriminant function analysis, both methods classified the apples tested into groups according to harvest date. After storage, the groupings were more diffuse. Results from sensory testing showed partial separation along the first linear discriminant but did not classify the apple into distinct groups. Important differences between treatments were found for “overall flavor”, “acid flavor” intensity, “crispness”, “cider/fermented aroma”, “vegetative aroma”, and “canned pear aroma”. Keywords: Electronic nose; apple; maturity; flavor; sensory analysis; GC/MS