Phytochemicals and Bioactive Compounds in Tropical and Subtropical Fruits - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 53

Hyrolyzable tannins
Hydrolyzable tannins are the class of tannins that can be
hydrolyzed by weak acids or weak bases to produce car-
bohydrate and phenolic acids, while on heating them with
hydrochloric or sulfuric acids yield gallic or ellagic acids.
Pomegranate fruit was found to contain hydrolysable tan-
nins including gallotannins, ellagic acid tannins, and gal-
lagyl tannins (Gil et al., 2000). The antioxidant properties
of pomegranate juice were attributed to its high content in
punicalagin isomers and ellagitannins (Cerda et al., 2003),
which are hydrolysable tannins.

total phenolic content of Thai bael fruit ( Aegle marme-
los [ L. ] Correa ) was 87.34 mg GAE/g (dry-wt) (Charoen-
siddhi and Anprung, 2008). Phenolic compounds, such
as myricetin and apigenin (Miean and Mohamed, 2001),
are relatively high in guava fruits; Luximon-Ramma et al.
(2003) reported that the total phenolic content was 247.3
and 126.4 mg GAE/100 g in white and pink pulp, respec-
tively. The ranges of total phenolic contents (mg/100 g)
were 47.9 in pineapple, 56.0 in mango, 57.6 in papaya, and
28.8 in litchi (Luximon-Ramma et al., 2003).
The major phenolic compounds of bananas include
catecholamines such as dopamine. The dopamine con-
tent in peel was found to be higher than in the pulp,
whereby the former had dopamine levels ranging from 80 to
560 mg/100 g and the latter 2.5 to 10 mg/100 g (Kanazawa
and Sakakibara, 2000).

Occurrence of phenolics
In general, the concentration of phenolic compounds in
foods is reported as “total phenolic” content. Table 4.1
shows the total phenolic content of some tropical and sub-
tropical fruits.
Total phenolics, as gallic acid equivalent (GAE), in two
pineapple varieties, 'Phulae' and 'Nanglae,' was found
to be 26.20 mg GAE/100 g and 20.28 mg GAE/100 g
(fresh-wt), respectively (Kongsuwan et al., 2009). The

Carotenoids
Carotenoids represent one of the most widespread groups
of naturally occurring pigments. The carotenoids are
lipid-soluble plant pigments that are either oxygenated or

Table 4.1. Total polyphenol content of tropical and subtropical fruits.

Total Phenolics (mg/kg GAE 1 ) Fruit Reference

Banana 215.7 Faller and Fialho (2009)

24.4-72.2 Alothman et al. (2009)

14 Patthamakanokporn et al. (2008)

Guava 123-191 Alothman et al. (2009)

148 Patthamakanokporn et al. (2008)

Mandarin orange 134.1 Faller and Fialho (2009)

Mangosteen 85 Patthamakanokporn et al. (2008)

Mango 110.5 Faller and Fialho (2009)

72.3 Melo et al. (2006)

113 Patthamakanokporn et al. (2008)

Mango (unripe) 71 Patthamakanokporn et al. (2008)

Orange 114.6 Faller and Fialho (2009)

92.4 Melo et al. (2006)

Papaya 15.3 Faller and Fialho (2009)

75.4 Melo et al. (2006)

54 Patthamakanokporn et al. (2008)

Pineapple 85.1 Faller and Fialho (2009)

66.3 Melo et al. (2006)

Pineapple (var. Phulae ) 26.2 Kongsuwan et al. (2009)

Pineapple (var. Nanglae ) 20.28 Kongsuwan et al. (2009)

Honey pineapple 34.7-54.7 Alothman et al. (2009)

Thai bael fruit 87.34 Charoensiddhi and Anprung (2008)

1 Gallic acid equiv., fresh-wt basis.