Influence of sulphate nutrition on flavour components of three cruciferous plants: Radish (Raphanus sativus), cabbage (Brassica oleracea capitata) and white mustard (Sinapis alba)

Abstract

The effect of sulphate nutrition on the flavour components of three members of the family Cruciferae (radish, cabbage and white mustard) has been investigated. The plants were grown in a glasshouse in sand culture at six concentrations of sulphate in the nutrient medium and their flavour characteristics determined by sensory and gas-chromatographic methods. The latter were based on (a) headspace samples from the raw and cooked vegetables and (b) solvent extracts chromatographed at 200 "C. Sensory tests showed that the flavour strengths of the vegetables increased from low values at extreme sulphur deficiency to maxima with increase of the sulphate available to the plant. For radish and mustard, there was no correlation between total volatile components (determined by the headspace method) and sulphur content but a highly significant correlation was demonstrated between the latter and less volatile flavour components present in solvent extracts. In the case of mustard seed, p-hydroxybenzyl isothiocyanate was determined colorimetrically and shown to be correlated with sulphur nutrition. With cabbage, ally1 isothiocyanate and total volatile content were determined by a headspace method and each was found to be significantly correlated with sulphate nutrition.It is suggested that the flavour of these plants consists of at least two types of components : (a) compounds which impart a bland, generalised "vegetable" flavour to the food and (b) a specific component or components which are perceived as a burning sensation on the tongue sometimes accompanied by acharacteristic odour. The former are independent of sulphur nutrition whilst the concentrations of the latter are highly correlated with sulphur nutrition.The effect of sulphate nutrition on growth response, visual deficiency symptoms and mineral composition has been reported.

Changes in thiocyanate content in some radish Raphanus sativus L. cultivars during hypocotyl-root growth

“…The increased synthesis of glucosinolates in leaves during this stage of radish ontogeny was observed also by Chong and Bible (1974). The downward tendencies of these compounds content were explained as being due to the so-called "diluting effect" which was to take place during intense root enlargement (Freeman and Mossadeghi 1972a, Kim et al 1983. It was possible to assume such an attitude in the case of daikons and only in the initial period of their root weight growth, The subsequent increase in thiocyanate content proceeded yet in parallel with the very intense increment of root weight (harvests II -IV) and together with considerable retardation of storage-root growth (harvest IV -V).…”

Taste and Flavor Perceptions of Glucosinolates, Isothiocyanates, and Related Compounds

“…These attributes are more subtle and easier to “separate” cognitively in species of rocket ( E. sativa and D. tenuifolia ) and watercress ( Nasturtium officinale ), where pungency is not as intense. The intensity of ITC flavor strength has been linked with agronomic practices, such as the application of nutrient sulfur in radish, and may be an agronomic means of increasing pungency without intensive breeding in the short term.…”

Triangle tests indicate that irrigation timing affects fresh cabbage sensory quality

“…Some production factors may also play a role in human perception of cabbage quality. For example, panelists in triangle tests distinguished among cabbage grown under varying soil moisture and sulfur conditions (Freeman & Mossadeghi, 1972, 1973. Also, in employing a three-point hedonic scale and 82 panelists, Yano, Saijo, Sugawara, and Ohta (1990) detected differences in preference for shredded samples of five cabbage varieties and concluded that flavor and moisture content are highly important in determining preference.…”