Influence of Cold or Frozen Storage on Temporal Changes in Sulforaphane and Objective Taste Values of Broccoli (<i>Brassica oleracea </i>var. <i>italica</i>) Florets

Abstract

Concentration of sulforaphane in broccoli is known to be enhanced during storage under an atmosphere of low O 2 (0.002-1.3) and high CO 2 (20.6-25.4). However, maintaining this concentration at a maximum is problematic. Therefore, storage of broccoli florets at low temperatures was investigated. Results showed that storage for 2 days under hypoxia significantly increased (3.3-fold against initial value) sulforaphane concentration. Subsequently, 4 days storage at three temperature levels was conducted. Sulforaphane levels were not maintained at 20 (normal temperature) or 1 (cold temperature). However, after storage at Ϫ20 (frozen) for 4 days, the sulforaphane concentration was not significantly reduced compared with the maximum level on day 2. Meanwhile, this concentration was not significantly higher than those at 20 or 1 on the same day. Storage under hypoxic conditions is known to affect the flavor and taste of vegetables. Therefore, eight taste factors were objectively measured using an electronic tongue. Astringency and bitterness were stable and independent of storage period and temperature, while other tastes were significantly affected by storage period. The rich umami value at Ϫ20 was significantly higher than that at 20 , and in general it was challenging to maintain taste values even for cold or frozen storage.

Analysis of Primary Metabolites in Cabbage (Brassica oleracea var. capitata) Varieties Correlated with Antioxidant Activity and Taste Attributes by Metabolic Profiling

“…The electronic tongue functions as an alternative to this process; it can be used to more objectively identify and quantify tastes [23] and has already been successfully applied to a variety of foods [23,24,25]. There are a small, but growing, number of reported applications of the electronic tongue to Brassica vegetables, including a recent study on the taste evaluation of broccoli flowers [26].…”

Prediction of Degreening Velocity of Broccoli Buds Using Hyperspectral Camera Combined with Artificial Neural Networks

“…botrytis]) [1]. Since the early 1980s, broccoli has been reported as a food to depress cancer [2] since it includes sulforaphane [3,4], which is useful for depressing the growth of Helicobacter pylori, the main reason for gastric cancer [5]. However, loss of green color (degreening) is the main phenomenon that decreases the shelf life of harvested broccoli [6] and is induced by the reduction of pigment (chlorophyll) [7].…”