Changes of Sensory Properties and Antioxidant Activity of Citrus reticulata ‘chachi’Pulp during Fermentation

To study the changes of sensory,chemical composition and antioxidant activity in the process of yeast fermented fruit juice of Xinhui Citrus reticulata'chachi’(CFJ),and promote rational utilization of the fruit pulp of Citrus reticulata'chachi’,the sensory properties were evaluated with six aspects of tissue state,color,sour taste,sweet taste,bitterness and aroma.The contents of total acid,reducing sugar,total phenols and total flavonoids were determined during fermentation. Meanwhile,the aroma components and relative contents were analyzed by gas chromatography-mass spectrometer.The antioxidant activity was evaluated with the clearance capacity of DPPH and OH free radicals. The results showed the fermented CFJ characterized with moderate taste,weak bitterness,fruity and fermented flavor was prepared under 0.5% inoculum of yeast A1 for 0~96 h culture at 40 ℃. The content of olefin in volatile aromatic substances was the highest,which increased from 53.70% to 77.77% after 0~96 h fermentation,and the main components were d-limonene and γ-terpene,followed by alcohols which decreased from 34.50% to 16.05%,esters from 7.74% to 2.44%,aldosterone and phenols(<1%). Furthermore,the contents of total acid and reducing sugar decreased gradually,while the content of total phenol and total flavone decreased significantly and then increased slightly. DPPH· scavenging rate decreased gradually during fermentation,which was significantly correlated with the contents of total phenols,total flavonoids,total acids and reducing sugar(P<0.05). The removal of ·OH decreased gradually and was significantly correlated with total acid content(P<0. 01),furtherly it was significantly correlated with total flavonoid content and reducing sugar content(P<0. 05). There was no significant correlation between ·OH clearance and total phenol content(P>0. 05).