II. LITERATURE REVIEW
2.1 Mangosteen Fruit Development and Maturity Indices
Mangosteen fruits are produced singly at the end of the branchlets, and usually do not mature and ripen uniformly. The tree will bear coexisting
generations of fruit, resulting from successive generations of flowers. Therefore, not all the fruits will reach maturity or ripen at the same time. Mangosteen fruits
take 5 to 6 months to mature from fruit set. Initially, fruit growth is dominated by the pericarp, with aril dry matter not increasing until 20 days from anthesis and
then continuing throughout the fruit development. At 13 weeks the fruit shows
the highest percentages of pulp, rind, sugar and acid: 29.37, 69.14, 18 and 0.49, respectively Kanchanapom and Kanchanapom, 1998. During ripening, a
thick, clear green cortex changes to dark purple or red purple. Enclosed by the rind are 4-8 edible white segments. The flavor is slightly acidic, but sweet
Nakasone et al., 1998. At present, there is no standard or uniform maturity index that is universally
used. Countries such as Malaysia, Thailand and Australia have developed their own maturity indices for harvesting to meet various marketing purposes. For
harvesting maturity indices used by growers in Australia, fruit harvested at stage 1 with pale yellow-green color, pH 3.9, rind thickness 9.0 mm, Brix12, and
firmness index 7.9, and stage 2 with botchy pink color, pH 3.3, rind thickness 7.7mm, Brix14 and firmness index 6 are not acceptable. Fruit harvested at
stage 3 with pinkish red, pH 3.2, rind thickness 7.4mm, Brix16, and firmness index =5; fruit harvested at stage 4 with maroon-red, pH 3.2, rind thickness
7.2mm, Brix16, firmness index 5; and stage 5 with maroon-violet, pH 3.2, rind thickness 7.0mm, Brix16, firmness index=5 are acceptable. Fruit
harvested at stage 6 with violet-black, pH 3.6, rind thickness 6.8mm, Brix14, and firmness index=5 is also unacceptable. However, Tongdee and Suwanagul
1989 reported that fruits are at the edible, ripe stage when the skin has darkened to a reddish purple, no latex remains in the skin, and the flesh segments separate
easily from the skin, and soluble solids content ranges from 17 to 20 and titratable acidity ranges from 0.7 to 0.8 pH = 4.5 to 5.0 Kader, 2002.
Table 1. Mangosteen Maturity Indices Developed in Malaysia
Stages Skin Color changes
Stuitability Fruit and half
fruit showing color changes
This fruit is yellowish green with red patches. At
this stage the pulp and the rind are not separable
The fruit, if harvested at this stage would
develop a poor flavor
1 The fruit is pale yellow or
green, with pink spots scattered over the part of
the skin. The quality of the
pulp is still low.
2 The fruit has the light
yellow- pink color with pink patches scattered all
over the skin. The skin and pulp can be separated.
Fruit harvested at this stage will give a
good quality flavor.
3 The fruit is evenly pink in
color. The patches of pink seen in stage 2 enlarge and
merge so as to become congruent. The pulp can be
separated from the rind. Fruit at this stage is
suitable for export.
4 The fruit color is now red
brownish red. Separation of the pulp and rind is easy.
The fruit is also suitable for export.
5 The fruit is red-purple in
color. No gum is presented in the rind. The pulp and
rind are readily separated. The fruit is suitable
for consumption.
6 The fruit is now purple,
dark purple or black. The rind contains no gum. Pulp
and rind are readily separated.
The fruit is suitable for consumption.
Sources: MOA 2002 4
2.2 Mangosteen Fruit Quality and Color Development
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