Tropical fruits are appreciated by consumers for their distinct aroma quality and exotic taste. Important amounts of tropical fruits such as pineapples are exported from their production countries to European and North American markets. Most of the pineapples destined for European fresh markets are harvested at a premature green-ripe stage and exported by cargo ships to be marketed in the low-price segment.
In contrast, fully ripe fruits, characterized by a limited shelf-life, are offered as a niche product on European premium markets, thus they are to be exported by rapid air freight. However, consumers expect superior quality and sensory properties when purchasing such fruits labelled as "air freight" and "by air", respectively.
German scientists investigated the influence of harvest maturity, fruit logistics and post-harvest storage on the sensory properties of fresh MD2 "Extra sweet" pineapple fruits.
Particularly, the differences in volatile profile of differently ripened fresh pineapples were evaluated by comparing fruits harvested at full maturity (FR) exported by rapid air freight to pineapples harvested at an earlier green-ripe stage (GR). The latter fruits were exported by sea freight and analyzed upon arrival at their destination and after postharvest flavour genesis. Air- and sea-freighted fruits arrived at their final destination 2 (FR 2 dah) and 14 (GR 14 dah) days after harvest, respectively. For the evaluation of postharvest flavor genesis, green-ripe sea-freighted pineapples were to be stored for a further 11 days (GR 25 dah).
Results showed significant differences in both volatile profiles and sensory characteristics of the differently ripened and postharvest handled pineapples.
Fully ripe air-freighted pineapples were characterized by elevated concentrations of two 1,3,5,8-undecatetraene isomers, methyl 3-methylbutanoate and 4-methoxy-2.5-dimethyl-3(2H)-furanone, which have been reported as potent contributors to the pineapple flavour.
Compared to fully ripened fruits, development of volatiles of sea-freighted pineapples upon arrival in Europe was rudimentary. Postharvest storage of sea-freighted pineapples resulted in a different volatile profile due to the genesis of hydroxylated and acetoxylated methyl esters and hexanal.
Fully ripe fruits were characterized by a pineapple-like note, fruity flavors and a sweet taste. In contrast, most of these attributes resulted at lower intensities in premature green-ripe fruits. Untrained panellists clearly preferred air-freighted to the sea-freighted fruits.
Moreover, preference among sea-freighted samples upon arrival in Europe (GR 14 dah) and those fruits that were stored for post-harvest flavour genesis (GR 25 dah) did not differ.
Scientists conclude that the distinctive pineapple-like aroma characterising the air-freighted fruits may decide about the consumers' preference, and the study will continue aiming at the identification of volatiles responsible for the cardboard-like and musty/corky off-flavours observed during post-harvest storage of sea-freighted pineapples.
