Chemical and sensory characterisation of whole and fractionated myrosinase-free extracts from selected Australian-grown, raw Brassica vegetables (broccoli, cauliflower, Brussels sprouts and red cabbage) was carried out to determine the contribution of key phytochemicals (i.e. glucosinolates, free sugars, phenolics) to the taste profiles of these vegetables. Glucosinolate (GS) and phenolic profiles were determined by liquid chromatography coupled with photodiode array detection and mass spectrometry. Ten glucosinolates (GS) were quantified across the vegetables investigated. Brussels sprouts (186.3 μg g(-1) FW) followed by broccoli (164.1 μg g(-1) FW) were found to contain the most GS. The phenolic profiles of all samples were dominated by hydroxycinnamic acid derivatives. As expected, red cabbage was the only vegetable with a significant anthocyanin signal (574.0 μg g(-1) FW). Red cabbage (26.7 mg g(-1) FW) and cauliflower (18.7 mg g(-1) FW) were found to contain a higher concentration of free sugars than Brussels sprouts (12.6 mg g(-1) FW) and broccoli (10.2 mg g(-1) FW). Descriptive sensory analysis of the whole extracts found sweetness (cauliflower and red cabbage sweeter than broccoli and Brussels sprouts) and bitterness (Brussels sprouts more bitter than others) as the most discriminating attributes. A hydrophilic fraction with sweetness, umami and saltiness as the main attributes was the most taste active fraction across all Brassica whole extracts. Sub-fractionation showed that this fraction was also bitter but the presence of sugars counteracted bitterness. Several components within each extract were found to contribute to the bitterness of whole Brassica extracts. The total and individual GS content alone could not explain the perceived bitterness of these extracts. Phenolics and/or other components are likely to be contributing to the bitterness associated with these vegetables.

Crassostrea gigas, the most common oyster species grown around the world, adapts to different climates, water qualities and growing technique. Its composition is known to vary according to these factors but what about its sensory properties? The objective of this study was to develop a method that would measure objectively oysters' sensory properties and demonstrate that descriptive sensory analysis can be applied to establish relationships between sensory and biochemical measurements, with a view to understanding the impact of changes in growing conditions and techniques on sensory properties. Oysters were sampled from three oyster growing areas. They were presented to a panel of assessors trained specifically to evaluate their appearance, aroma, flavour and aftertaste characteristics following an objective protocol. Proximate composition and content of fatty acids and free amino acids were measured in replicate oysters from the same batches. The panel developed a vocabulary of 12 terms that all measured significant differences between the oysters. Significant differences were also found in the composition of oysters. Relationships between compositional measurement and sensory perception were established that reflect the impact of some growing factors. Insights gained from this study could assist the oyster industry to achieve optimized growing techniques and marketing strategies.

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