不同熟度‘珍珠拔’番石榴及‘台農二號’番木瓜果實之抗氧化力

Abstract

‘珍珠拔’番石榴(Psidium guajava cv. ‘Jenju Bar’)及‘台農二號’番木瓜(Carica papaya cv. ‘Tainong No.2’)為台灣常見具高抗氧化力熱帶水果。本試驗以三價鐵離子還原法測定不同熟度之珍珠拔番石榴及台農二號番木瓜果實之抗氧化力，並分析果肉中維生素C及總酚類含量。 分析相異直徑果實之抗氧化力可得知番石榴果實抗氧化力大致隨著果實增大而下降。不同季節珍珠拔番石榴果實發育所需時間不同，夏季果實由開花至果實成熟約需113天，冬果則需140天。但兩季果實抗氧化力及抗氧化物質變化趨勢相似，果肉抗氧化力及總酚類含量隨果實發育而下降，而維生素C含量於果實接近成熟時有上升之趨勢。成熟夏果之總酚類含量高於冬果，而冬果具有較高之維生素C含量。以單位濃度乘上果實重量可得單一果抗氧化物之總量。珍珠拔果實發育期間，雖然果肉抗氧化力以及抗氧化物質濃度因果實膨大而被稀釋，但單一果實之抗氧化力與抗氧化物總量則隨果實發育持續累積。 番木瓜果實發育期間抗氧化力及抗氧化物之變化趨勢與番石榴相異。台農二號番木瓜冬季果實自花後56天至196天完全黃熟期間，果肉之抗氧化力、維生素C及總酚類含量持續上升，且上升趨勢於果實後熟階段更加顯著。 採收全株由盛花後至20%轉色之不同熟度果實，數據依形成果實之花序順序由上往下換算為十區段，以表現果實生長情形及抗氧化物含量變化趨勢，且利於植株間比較。當果實隨區段數增加漸趨成熟，果肉之抗氧化力及抗氧化物含量呈現先降後升之變化趨勢，顯示發育初期之番木瓜果實之抗氧化力與抗氧化物質含量較接近於成熟果，而高於發育中期之果實。 電石催熟可提昇番木瓜之抗氧化力。催熟兩天再置於25℃環境下三天達到完全後熟之番木瓜果實，果肉之抗氧化力、維生素C及總酚類含量分別為催熟前提昇24%、54%及26%。

'Jenju Bar' guava (Psidium guajava cv.' Jenju Bar ') and' Tainong No. 2' papaya (Carica papaya cv.' Tainong No.2 ') are common tropical fruits in Taiwan with high antioxidant activity. In this study, I investigated the antioxidant activity of these two fruit species in different maturity by ferric reducing antioxidant activity (FRAP) assay, I also measured the antioxidant content such as vitamin C and total phenolic compound (TPC). By investigating different diameter of guava fruits, the antioxidant activity of guava fruit generally decreased with the enlargement of fruit. In ‘Jenju Bar’ guava, summer crops took 113 days from bloom to maturity and winter crop needed 140 days, but the changes of antioxidant activity and antioxidant content are similar. The antioxidant activity and phenolic compound decreased with fruit development, but the content of vitamin C increased at mature stage. Mature summer crops had higher total phenolic compound, but mature winter crops had higher vitamin C content. Although the concentration of antioxidant content diluted during fruit expansion, the total antioxidant activity and antioxidant content of single fruit accumulated continuously. ‘Tainong No. 2’ papaya fruit showed a different trend from ‘Jenju Bar’ guava fruit, the antioxidant activity, vitamin C and phenolic compound rose during 56 days after bloom (DAB) to 196 DAB. The increasing trend is more obvious in the ripening stage. I also modified the data of whole tree fruits as ten sections to investigate the antioxidant activity of papaya fruit during development. When the fruits became mature with the increasing section, the antioxidant activity and antioxidants showed a downward first and then upward trend. The antioxidant activity and antioxidants content of fruits in early stage are higher than that of middle stage and similar to that of mature stage. The ripening treatment raised the antioxidant activity and antioxidants of papaya fruits. Papaya treated with calcium carbide for 2 days and then stored in 25 ℃ for 3 days to achieve full ripening, the antioxidant activity, vitamin C and phenolic compound of fruit pulp are 24%, 54% and 26% higher than those before ripening.