Influence of Different Growth Conditions on Saponarin, Water-Soluble Vitamins, and Mineral Content of Barley Sprouts Cultivated in Chamber System

Abstract

Barley sprouts contain various secondary metabolites such as polyphenol, policosanol, and γ-aminobutyricacid (GABA). In particular, saponarin, which accounts for about 72% of polyphenols, is well known for anti oxidant, anti-inflammatory, and liver function protection effects. Saponarin is greatly affected by environmentalconditions such as light, temperature, and moisture. However, there is a lack of studies about the effect of themicroclimatic environment on saponarin content in barley sprouts. This study was conducted to evaluate theinfluence of daily temperature range, light intensity, and light period on saponarin, water-soluble vitamins, andminerals content in barley sprouts. Seeds of Hordeum vulgare L. were sown on a plastic box and cultivated ingrowth chambers with different conditions by adjusting daily temperature range (DT, 0 → 10°C), light intensity(LI, 120 → 180 µmol m-2 s-1), and light period (LP, day 12 hours → day 18 hours). The plants were harvestedwhen the leaf length reach 15 cm. The fresh weight was not significantly different between each treatment, yetthe growth period was highest in barley sprouts cultivated with DT. Saponarin content was higher in DT, LIand LP than control, and highest saponarin content in DT. In contrast, vitamin C content was highest in controland lowest in DT. Similarly, vitamin B1 and B5 content showed the highest in control. Changes in light andtemperature elevated saponarin content in barley sprouts, especially daily temperature range showed adramatic increase. However, the change in daily temperature range affects an increase in growth period and adecrease in vitamin C content. In conclusion, daily temperature range is the predominant environmental factorto produce saponarin-enriched barley sprouts.