Abstract:

Sugarcane contains abundant polyphenols and flavonoids. In the present study, total polyphenols content,
flavonoids content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, hydroxyl radical scavenging capacity
and total reducing power were used as the indicators to evaluate the antioxidant activity of sugarcane juice, and the
corresponding wine and vinegar in vitro and after simulated human gastrointestinal digestion. Results showed that at the
alcohol fermentation alcohol extractable polyphenols and flavonoids were detected. At the acetic acid fermentation stage,
the contents of polyphenols and flavonoids presented some volatility. This may be related to the occurrence of oxidation
and hydrolysis during the fermentation process. The sugar cane vinegar possessed strong DPPH radical scavenging capacity
in vitro, and the sugarcane wine had strong hydroxyl radical scavenging capacity. A series of reactions of polyphenols and
flavonoids after simulated gastrointestinal digestion took place, and as a result, the contents of both compounds dropped very
significantly (P < 0.01) in simulated gastric environment, but increased slightly in simulated intestinal environment. The
antioxidant activity of the beverages in the human gastrointestinal environment is influenced not only by their antioxidant
substances, but also by pH, protease, phosphate and other physiological factors in the digestive juice.

Key words: sugarcane juice, sugarcane wine, sugarcane vinegar, polyphenols, flavonoids, simulated gastrointestinal environment, antioxidant activity