2.3. Parboiling
The paddy (0.5e2 kg) was soaked in previously boiled (w98 C)
tap water (2e3 L) and the mix was stirred, floating chaff removed
and the vessel covered with jute sacks and left overnight (Sashikala,
Singh, & Ali, 2005). Thewaterwas drained off and the soaked paddy
spread on small wire-mesh trays, and steamed in an autoclave at
open atmospheric pressure for 20 min. The paddy was then airdried
in the shade (1e2 days) to a safe moisture level. Parboiled
paddy obtained was dehusked and milled under similar conditions
as mentioned above (2.2.1 & 2.2.2).
2.4. Determination of soluble/insoluble dietary fiber
All samples of raw (dehusked head rice and brokens, polished
head rice and brokens) and parboiled (dehusked and polished head
rice) were pulverized in a mixer (Johnson Lady Bird plus), and the
flour was passed through 60-mesh sieve (250 mm). The flour was
gravimetrically defatted prior to fiber analysis by extracting with
petroleum ether (60e80 C) for 12e16 h using a Soxhlet apparatus
(AOAC, 2000). Total dietary fiber was analyzed as per Asp,
Johansson, Hallmer, and Silgestrom (1983) with slight modifications.
Reagents used were 0.1 mol/L sodium phosphate buffer, pH
6.0; 4 mol HCl/L; 4 mol/L NaOH; 95% of ethanol (95 mL of
ethanol þ 5 mL of water) and 78% of ethanol (78 mL of
ethanol þ 22 mL of water). The procedure in brief is as follows:
About one gram of defatted sample was suspended in 25 mL of
0.1 mol/L sodium phosphate buffer (pH 6.0) and treated with100 mL
of a- amylase at boiling water bath temperature for 15 min, and
cooled to room temperature. About 20 mL of distilled water was
added and the pH was adjusted to 1.5 with 4 mol HCl/L. About
100 mg of pepsinwas added and incubated at 40 C in a water bath
with agitation for 60 min. Twenty milliliters of distilled water was
added and the pH was adjusted to 6.8 with 4 mol/L NaOH. The