Stable isotope dilution assay and HS-SPME-GCMS quantification of key aroma volatiles of Australian pineapple (Ananas comosus) cultivars.

Pineapple aroma is one of the most important sensory quality traits that influences consumer purchasing patterns. Reported in this paper is a high throughput method to quantify in a single analysis the key volatile organic compounds that contribute to the aroma of pineapple cultivars grown in Australia. The method constituted stable isotope dilution analysis in conjunction with headspace solid-phase microextraction coupled with gas-chromatography mass spectrometry. Deuterium labelled analogues of the target analytes purchased commercially were used as internal standards. Twenty-six volatile organic compounds were targeted for quantification and the resulting calibration functions of the matrix -matched validated method had determination coefficients (R2) ranging from 0.9772 to 0.9999. The method was applied to identify the key aroma volatile compounds produced by popular pineapple cultivars such as 'Aus Carnival', 'Aus Festival', 'Aus Jubilee', 'Aus Smooth (Smooth Cayenne)' and 'Aussie Gold (73-50)', grown in Queensland, Australia. Pineapple cultivars varied in its content and composition of free volatile components, which were predominantly comprised of esters, followed by terpenes, alcohols, aldehydes, and ketones.

Review of the Aroma Chemistry of Pineapple (Ananas comosus).

Pineapple (Ananas comosus), one of the most flavorful and popular tropical fruits consumed worldwide, is known to contain many volatile organic compounds (VOCs) at varying concentrations. Much attention has been paid to understand which VOC plays a significant role in the sensory aroma notes of the fruit. Though, nearly 480 VOCs have been identified to date using different analytical techniques, only 40 compounds are reported to contribute to the unique flavor of pineapple. A consolidated database of the reported VOCs and key aroma compounds of pineapple is currently not available. This review discusses the available published data regarding the analytical methodologies, volatile profile of different varieties of pineapple at different maturities, and their characteristic aroma compounds. The output of this review is a subset of key pineapple aroma volatiles that can be targeted in analytical method development for utilization in varietal improvement or other research of pineapple.

The bracteatus pineapple genome and domestication of clonally propagated crops.

Domestication of clonally propagated crops such as pineapple from South America was hypothesized to be a 'one-step operation'. We sequenced the genome of Ananas comosus var. bracteatus CB5 and assembled 513 Mb into 25 chromosomes with 29,412 genes. Comparison of the genomes of CB5, F153 and MD2 elucidated the genomic basis of fiber production, color formation, sugar accumulation and fruit maturation. We also resequenced 89 Ananas genomes. Cultivars 'Smooth Cayenne' and 'Queen' exhibited ancient and recent admixture, while 'Singapore Spanish' supported a one-step operation of domestication. We identified 25 selective sweeps, including a strong sweep containing a pair of tandemly duplicated bromelain inhibitors. Four candidate genes for self-incompatibility were linked in F153, but were not functional in self-compatible CB5. Our findings support the coexistence of sexual recombination and a one-step operation in the domestication of clonally propagated crops. This work guides the exploration of sexual and asexual domestication trajectories in other clonally propagated crops.