Effects of roasting and steeping on nutrients and physiochemical compounds in organically grown naked barley teas

Abstract

Barley tea, a popular beverage with cultural traditions in East Asia, has long been esteemed for its flavor, aroma, thirst-quenching properties and perceived health benefits attributed to bioactive compounds. This study investigated the nutritional, bioactive, and antioxidant aspects of three commercial naked barley varieties, focusing on the impact of roasting and subsequent steeping for tea. Roasting did not affect total dietary fiber or β-glucan content. The process reduced sugar content and led to the disappearance of free amino acids, contributing to high levels of acrylamide and color changes. Roasting diminished total phenolic compounds, particularly flavonoids, resulting in reduced antioxidant activity. Metabolite analysis identified compounds in roasted grains that could influence tea flavor and aroma. Roasted barley tea made from these varieties was not a source of dietary fiber or antioxidants, but also contained no acrylamide. Therefore, consumers seeking such benefits from barley are urged to consume whole grain foods.

Highlights

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  Roasting whole grains causes modest modifications in nutritional composition.

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  Fiber and antioxidants are eliminated when roasted grains are steeped for tea.

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  Roasted grain is dangerously high in acrylamide.

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  Steeping roasted grain for tea leads to no detectable acrylamide.

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  The flavor, aroma, and thirst-quenching properties of barley tea merit more research.