S11 - Session P1 - Investigating the aroma and sensory attributes of fresh herbs

Authors: Ana Cristina Contente *, Maria Jose Oruna-Concha, Carol Wagstaff

The consumption of culinary herbs has increased as flavour enhancement for meals is sought from alternatives to salt. This study aimed to correlate the aroma and sensory variation of fresh basil ( Ocimum basilicum L.), coriander ( Coriandrum sativum cv. Cruiser) and rosemary ( Rosmarinus officinalis ) with cultivation parameters such as temperature, season and production method. The three herbs were grown at different locations across the United Kingdom (open field, protected field, protected pot and protected hydroponics) for two production seasons over three consecutive years. Volatile analysis was conducted using Solid Phase Micro-Extraction and Gas Chromatography-Mass Spectrometry. Basil pot produced samples had significantly (p < 0.05) lower levels of phenylpropanoids and monoterpenes compared to hydroponic grown basil. Comparison between hydroponic grown basil samples that experienced different seasonal/annual temperatures, revealed that the optimum for phenylpropanoids and monoterpenes accumulation was 20-25 ˚C, with these compounds much reduced outside that temperature window. Pot grown rosemary had significantly (p < 0.05) lower monoterpenes and monoterpenoids abundance than open field grown samples. Comparing seasons between field-grown samples revealed that monoterpenes were absent at temperatures below 22 ˚C, but that these compounds accumulated in field conditions from 22-29 ˚C across the growing cycle. Coriander showed a significantly (p < 0.05) higher abundance of aldehydes in samples grown in open field compared to pots. Temperatures in the field below 16 ˚C and irrigation below 20 mm/week were correlated with reduced abundance of aldehydes compared to warmer, well-watered field conditions. In summary accumulation of phenylpropanoids/monoterpenes/aldehydes compounds, which are the major aromatic constituents of herbs, is reduced by sub- or supra-optimal temperatures, and appears to be reduced in pot produced herbs compared to the same variety grown in the field. More production variables, such as daylength, light quality, soil type, need to be analysed to fully understand the relation between agronomical practice and herb flavour.