Investigation of phytochemical constituents, phenolic profiles and antioxidant activities of ricegrass juice compared to wheatgrass juice

Background: Cereal grass has been brought attention as a new functional food. Wheatgrass juice was known as a super food which provides lots of advantages for human health. However, the young stage of rice sprout has not been made widely known for consumption, though it is in the similar family to wheat (Poaeceae). Accordingly, ricegrass juice can and should be introduced, especially in Asian countries, as an economical functional drink. Nevertheless, currently there is none of the apparent evidences which confirm the nutritive values of ricegrass juice compared to wheatgrass juice. Objective: To investigate the chemical compositions, major phytochemical constituents, bioactive compounds content, specific phenolic profiles, and in vitro antioxidant activities of ricegrass juice compared to wheatgrass juice. Methods: Rice and wheat seeds were germinated and grown hydroponically for 8 days. Both fresh plants were determined for chemical compositions. Next, the grasses were extracted with water, centrifuged, and the supernatants were tested for chlorophyll, carotenoid, and ascorbic acid contents. The left-over supernatant were freeze-dried. The extracts were then screened for the main group of phytochemicals, total extractable phenolic and specific phenolic compounds. Lastly, the extracts were tested for the antioxidant activities using DPPH, ABTS, FRAP, FCA and HRSA. Results: Data revealed that wheatgrass contained higher levels of protein and fat. Both ricegrass and wheatgrass juice extract exhibited the group of phenol, tannin and saponin but not alkaloid, flavonoid, sterol, terpenoid, courmarin, and cardiac glycoside. Wheatgrass juice can be detected for higher level of ascorbic acid and chlorophyll. Both grass juices were found the similar phenolic acids analyzed by HPLC included pyrogallol, vanilic acid, syringic acid and ferulic acid, however, ricegrass juice contained larger amounts of all phenolic acids excluding syringic acid. Conversely, wheatgrass juice exposed higher antioxidant activities for all methods. This may propose from the synergistic effects of ascorbic acid, chlorophyll, and phenolic compounds in wheatgrass juice, while the main composites exhibited antioxidant activities in ricegrass were phenolic compounds. Conclusion: Ricegrass juice contained great level of phenolic acid molecules. Even if ricegrass juice gave less statistically ability on antioxidant activities, they still had comparable levels of antioxidant activities. With the reduction in cost of raw materials and contribution of high nutritional values, ricegrass juice could be introduced as an antioxidant boosting drink in competition to wheatgrass juice.