Identification of Causal Factors of Peel-Pulp Splitting and Peeling Difficulty Disorders in ‘Mas’ Banana [Musa Sapientum Cv. Mas (Aa)]
‘Mas’ banana is among the most favoured of all the local dessert bananas because of its fascinating golden peel and light orange, aromatic and sweet pulp. However, this dessert cultivar was found to be susceptible to peel-pulp splitting disorder (PPSD) and peeling difficulty disorders (PDD). Thus...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2007
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| Online Access: | http://psasir.upm.edu.my/id/eprint/5296/1/FSTM_2007_2.pdf http://psasir.upm.edu.my/id/eprint/5296/ |
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| Summary: | ‘Mas’ banana is among the most favoured of all the local dessert bananas because
of its fascinating golden peel and light orange, aromatic and sweet pulp. However,
this dessert cultivar was found to be susceptible to peel-pulp splitting disorder
(PPSD) and peeling difficulty disorders (PDD). Thus, study was conducted to
identify the causal factors of PPSD and PDD of Mas banana during fruit
development and ripening, respectively.
Incidence of PPSD and the physical characteristics of the fruits were determined at
harvest dates of 4, 5, 6, 7, 8 and 9 weeks after flower emergence (WAFE) for three
fruiting seasons (FS1, FS2 and FS3). Chemical characteristics and nutrient
contents in PPSD and normal fruits harvested at 6, 7, 8 and 9 WAFE were
determined. The anatomical characteristics of the PPSD and normal fruits were
also studied. Incidence of PPSD was found to be the most severe at FS3 which was
a rainy season after a drought season. Incidence of PPSD was significantly
(P≤0.05) and positively correlated to fruit circumference, pulp weight and pulp to peel ratio. This suggested that the increase in fruit splitting was related to a rapid
increase in fruit size. Significant (P≤0.05) increases in pulp moisture content and
significantly (P≤0.05) higher peel moisture content of PPSD fruits suggested that
rapid increase in pulp volume had put stress on the peel and caused the fruit to
split. Significantly lower peel calcium in PPSD fruits also suggested that PPSD
was a Ca-deficiency disorder which had caused a lower cell wall turgidity and
intercellular strength in the fruits. Results obtained for soluble solids
concentration, titratable acidity and pH of the fruits indicated that the fruits had
achieved harvest maturity at 6 to 7 WAFE. As shown in the scanning electron
micrographs (SEM), the intercellular space of PPSD fruits had been fully occupied
due to the rapid cell expansion, imposing stress on the peel which rendered the
fruit to split.
Occurrence of PDD was determined on fruits ripened at three levels of RH (high –
90 ± 5%, medium – 70 ± 5 %, low – 50 ± 5 %) during 5 to 8 ripening days. The
corresponding quality and anatomical characteristics of the fruits in relation to
PDD were also determined. Fruits ripened at low and medium RH conditions
manifested PDD. There was an advanced ripening in fruits ripened at low RH as
compared to fruits ripened at medium and high RH. This was shown by the
significant (P≤0.05) linear and quadratic relationships between peel colour (L* and
C*) and ripening day. Occurrence of PDD was significantly (P≤0.05) and
positively correlated to weight loss and sugar: acid, but was negatively correlated
to peel thickness and peel moisture content. These indicated that PDD increased
with an increase in moisture loss when ripened at RH lower than 70%. SEM
showed that severe water loss in fruits caused the cells to contract and loss turgor, resulting in loss of cell wall turgidity and reduced intercellular spaces. Thus, peelpulp
transition layer was not readily separated from the outermost layer of the pulp
because of absence of intercellular spaces to facilitate peeling. |
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