Elasticity Index, Quality and Shelf-life of 16 Tree-ripe Mango Cultivars

Elasticity index (EI), quality during storage, and shelf-life (SL) were assessed in 16 cultivars of tree-ripe mango fruit. All fruits were individually wrapped in polyethylene film and stored for 10 days at 25 degrees C. EI rapidly declined over the first 2 days of storage regardless of the cultivar, after which the decline was more gradual. EI reduction rate (EIRR) from day 2 to day 10 of storage was lowest (7 % and 9 %) in 'Irwin' and 'Glenn', followed by 'Khieo Sawoei'. After 10 days, the EI for these cultivars was 57-79 x 10(5) f(2)(2).m(2/3) (f(2), second resonance frequency; m, fresh weight of a fruit). In contrast, EIRRs for 'Dot' and 'Valencia Pride' cultivars were 66 % and 59 %, respectively, and that of 'Amataiko' was 48 %; EI after 10 days of storage for these cultivars was 23-30 x 10(5) f(2)(2).m(2/3). EIRRs of the other 10 cultivars were between 23 % and 41 %. Weight loss after 10 days of storage was highest in 'Dot' and 'Amataiko' (4.6 % and 3.6 %), but lower in the other cultivars (1.4 % to 2.4 %). The degree of water-soaked symptoms (WSS, translucent flesh tissue) was greatest in 'Alphonso', followed by 'Valencia Pride', 'Dot', 'Spirit of '76', 'Nam Doc Mai', 'Golden Lippens', and 'Aikou'. In contrast, no WSS were observed in 'Irwin', while 'Beni Keitt', 'Edward' and 'Glenn' showed few symptoms, and 'Amataiko' showed slightly more WSS. SL score of each fruit was calculated by adding the score obtained by El (0 to 3) to a score based on the degree of WSS after 10 days of storage (also 0 to 3). SLs (SL of more than 10 days under room temperature can be estimated) were good for 'Irwin', 'Glenn', 'Edward', and 'IChieo Sawoei'; moderate (SL of 8-10 days) for 'Beni Keitt', 'Sensation', 'Florigon', and 'Tommy Atkins'; poor (SL of 4-5 days) for 'Amataiko', 'Aikou', 'Nam Doc Mai', 'Golden Lippens', and 'Spirit of '76'; and very poor (SL of 2-3 days) for 'Alphonso', 'Valencia Pride', and 'Dot'. These results clearly revealed cultivar differences in EIRRs, WSS and SLs of ripe mangoes, and suggested the possibility of estimating SL based on EI and the degree of WSS after storage.