No abstract

Pigmented barley cultivars (purple, blue, and black barley) were processed by germination and roasting to develop pigmented barley tea, and the changes in their physicochemical and antioxidative properties were investigated. The L * (lightness), a * (redness), and b * (yellowness) values of the pigmented barley increased after the germination and roasting process. Crude protein, fat, and ash contents in the pigmented barley were increased by the germination and roasting process, whereas total starch and β-glucan contents decreased. The γ-aminobutyric acid content of the pigmented barley cultivars were slightly higher than an ordinary barley cultivar, but they decreased after germination and the subsequent roasting process. The total anthocyanin content of the pigmented barley also decreased after processing. The total phenolic and flavonoid contents were increased by the germination and roasting process, and the highest contents were observed in purple barley. The in vitro antioxidant activity (DPPH, ABTS radical-scavenging activity) of pigmented barley also increased after the tea-making process, and these were the highest in purple barley.

Red-pigmented rice was germinated and processed to develop germinated red rice tea, and the changes in physicochemical, bioactive, and microbial properties due to germination and roasting were investigated. The moisture and crude ash contents of red rice decreased after germination and roasting. Crude protein and crude fat contents increased after germination but slightly decreased after roasting. Total phenolics, flavonoids, and antioxidant activities (DPPH and ABTS radical scavenging activities) increased following germination and heat treatment. However, the increased levels of γ-amino butyric acid after germination significantly decreased during the subsequent roasting step. In addition, total bacteria, yeast, and mold counts increased during the germination process but decreased after heat treatment as compared to those in the original grain; Escherichia coli was not detected. Therefore, germination and subsequent roasting could effectively enhance the contents of the most bioactive compounds and maintain microbial stability in red-pigmented rice.