, Melly Novita and Ahmad, Siti Hajar and Ding , Phebe (2007) Selecting fruit quality characteristics to predict optimum harvest time of red pitaya (Hylocereus Polyrgizus) fruit. In: 18th Malaysian Society of Plant Physiology Conference, 21-23 Aug 2007, Kota Kinabalu, Sabah.
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This study was carried out to predict optimal harvest time of red pitaya (hylocereus polyhizus) fruit using selected fruit physical and eating quality characteristics. Pitaya fruits were harvested at 5-day interval beginning from 25 to 40 days after anthesis (DAA) and the fruit characteristics were measured. The growing degree days (GDD) were calculated from 5 to 40 DAA. Regression analysis was carried out to study the relationship between fruit characteristics and GDD. The correlation between selected peel and pulp,L*,C*,h⁰,firmness, sugar/acid ratio and flavour were determined for fruits at 483 to 765 GDD. Characteristics that were significantly correlated were used in a forward multiple regression analysis to develop a model to predict optimal harvest time.There were significant relationship between GDD and peel L*,C*,h⁰ with R²=0.90,0.95,0.93, respectively. There were also significant relationship between GDD and pulp *,C*,h⁰ with R²=0.95,0.76,0.92 respectively. Significant positive relationship were also obtained between GDD and sugar/acid ratio (R²=0.92) and flavour (R²=0.97), while significant negative relationship (R²=0.98) occured between GDD and firmness. There were significant correlations between peel L*,C*,h⁰, pulp L* and h⁰. There were also significant correlations between firmness and both peel and pulp L*,C*,h⁰. Sugar/acid ratio was negatively correlated with peel L*, peel h⁰, pulp L* and firmness and positively correlated with peel C*, pulp h⁰ and flavour. Flavour was positively analysis showed 50%and 35% of the variability in sugar/acid ratio was accounted for by peel L* and firmness, respectively (Sugar/acid ratio=480.97 - 8.16 (Peel L*) - 39.57 (Firmness)). The peel C* and firmness accounted for 38% and 35% respectively of the variability in flavour of red pitaya (Flavour = 1.58 - 0.01 (Peel C*) - 0.16 (Firmness). The peel C* and h⁰ accounted for 45% and 51% of the variability in firmness (Firmness = 5.83 - 0.10 (Peel C*) + 0.05 (Peel h⁰). These results suggest that peel C* and h⁰ could be used to predict optimal harvest time of red pitaya.
|Item Type:||Conference or Workshop Item (Paper)|
|Subject:||Fruit — Quality.|
|Faculty or Institute:||Faculty of Agriculture|
|Deposited By:||Erni Suraya Abdul Aziz|
|Deposited On:||16 Aug 2012 18:02|
|Last Modified:||16 Aug 2012 18:02|
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