Chaninneat Torsahakul. Minerals, phytate and tannin contents in selected thai fruits for health and diseases guildlines . Master's Degree(Nutrition). Mahidol University. : Mahidol University, 2007.
Minerals, phytate and tannin contents in selected thai fruits for health and diseases guildlines
Abstract:
A total of 37 varieties of fresh fruits and 4 kinds of fruits in syrup were collected from 6 local
markets and supermarkets in Bangkok during January to December 2006. The objectives were to
determine macro and micro minerals (sodium; Na, potassium; K, magnesium; Mg, calcium; Ca, iron;
Fe, zinc; Zn and copper; Cu), total polyphenol, tannin, catechin and phytate content and to determine
molar ratios between phytate and micro-elements, and to calculate these nutrients and non-nutrients
from one portion of each fruit group in food exchange lists. Sodium and potassium contents were
determined using flame atomic absorption spectrophotometer and other minerals were determined using
inductively coupled plasma–optical emission spectrometry (ICP-OES). All fruits were high in K (29.25
to 405.60 and 28.30 to 79.98 mg/100g edible portion for fresh fruits and fruits in syrup), especially ripe
banana (Kai and Hawm varieties) and durian (Chanee variety) (309.75, 346.98 and 405.60 mg/100g
edible portion). Both fruits and fruits in syrup were poor sources of some macro-minerals (Na, Mg and
Ca) and micro-minerals (Fe, Cu, Zn) with ranged from 0.59 to 16.32 (Na), 3.08 to 25.21(Mg), 1.17 to
22.09(Ca), 0.08 to 0.33(Fe), 0.04 to 0.27(Cu) and 0.04 to 0.28(Zn) mg/100g edible portion. Total
polyphenol, tannin and catechin were determined using Spectrophotometer. Total polyphenol, tannin
and catechin content of all fruit samples ranged from 4.67 to 322.63 mgGAE, 0.62 to 43.37 mg tannic
acid equivalent and 0.01 to 21.44 mg catechin equivalent/100g edible portion. Sugar apple (Nahng
variety) had the highest amounts of total polyphenol, tannin and catechin contents with approximately
322.63, 43.37 and 21.44 mg/100g edible portion. Phytate content was determined using ion-pair
reverse-phase chromatography. Phytate content ranged from 0.01 to 6.02 mg/100g edible portion. The
highest phytate content was found in dragon fruit. (6.02 mg/100g edible portion). When considering the
amount of macro–micro minerals in fruits and fruits in syrup from one portion of food exchange list, all
samples in this study had a small amount of macro-micro minerals with ranging from 0 to 11 (Na), 1 to
21 (Ca), 2 to 27 (Mg), 0.1 to 0.6 (Fe) and 0 to 0.3 (Zn) mg/portion, respectively, except K and Cu, since
almost all fruit samples were good source of potassium and copper, especially dragon fruit (325
mg/portion) which provided 9% of Thai RDI for K per one portion, lychee (Hohnghooway variety; 0.19
mg/portion) and green grape (0.26 mg/portion) which provide 10% and 13% of Thai RDI for Cu per
one portion. Strawberry was the highest source of total polyphenol (397.13 mgGAE/portion) and tannin
(28.49 mg tannin acid equivalent/portion) while star fruit is the greatest source of catechin (12.79 mg
catechin equivalent/portion). The range of phytate in all samples was between 0.02 to 7.22 mg/portion.
The highest of phytate content was found in dragon fruit. However, the molar ratios between phytate
and micro-elements of the present study were less than 2.06 for Phy/Fe, 4.20 for Phy/Zn and 39 for
Ca×Phy/Zn.