水果中含有豐富的抗氧化劑，包括營養素及物質，具有防止人體氧化性傷害的能力。本研究擬評估木瓜、白肉火龍果、珍珠芭樂及雪梨等四種產自台灣的巿售水果，經慢磨機榨汁，測量各種果汁抗氧化劑及抗氧化能力，包括維生素C及總多酚；總抗氧化力、自由基清除力及亞硝酸鹽清除力等。結果顯示，維生素C及總多酚含量，皆以珍珠芭樂汁的含量最高。在抗氧化能力方面，總抗氧化力以珍珠芭樂汁最強，自由基清除力以木瓜汁及珍珠芭樂汁為最強，亞硝酸鹽清除力以木瓜汁為最強。進一步性分析顯示，本實驗所有果汁樣本的維生素C含量及總多酚含量，均與總抗氧化力呈高度正相關性。

Fruits are rich in antioxidants, including nutrients and substances, which have the ability to prevent oxidative damage. The purpose of this study was to evaluate the antioxidants and antioxidative activity of guava, papaya, pitaya (white meat), and pyrus nivalis in Taiwan. The juice was extracted by masticating juicer. The antioxidant nutrient and substance, including vitamin C and total polyphenols, and the antioxidant activity, including trolox equivalent antioxidant activity, radical scavenging activity and nitrite scavenging activity were analyzed. The results showed that the contents of vitamin C and total polyphenols were the highest in guava juice. In terms of antioxidant activity, guava juice had the strongest total antioxidant activity, papaya juice and guava juice had the strongest free radical scavenging activity, and papaya juice had the strongest nitrite scavenging capacity. The Pearson Correlation test showed that the vitamin C content and total polyphenol content of all juice samples were highly positively correlated with the trolox equivalent antioxidant activity.