Physicochemical Properties And Prebiotic Potential Of Native, Resistant And Hcl-Resistant Starches From Sago (Metroxylon Sagu)
Loading...
Date
2016-04
Authors
Tan, Zi Ni
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Resistant starch type III (RS3) was produced from sago (Metroxylon sagu)
and evaluated for its physicochemical properties and potential as a prebiotic. A
sample with 35.7% RS3 content (designated as sago RS) was produced when the
native sago starch was suspended in distilled water, gelatinized by autoclaving at
121 °C for 1 h, followed by debranching with 20 U pullulanase per g starch at 60 °C
for 24 h, autoclaved again at 121 °C for 1 h before storage at 4 °C for 24 h. RS3
content was further increased with the treatment of sago RS with 0.5 M HCl at 60 °C
(sample designated HCl-sago RS) to 63.8%. Granules of sago RS and HCl-sago RS
had B-type X-ray diffraction pattern, high peak temperatures (143.7 °C and 146.5 ºC,
respectively) and showed irregular and rough surface structure. While granules of
native sago starch had C-type diffraction pattern, peak temperature of 74.6 °C and
smooth granular surface. The solubility and the swelling power of HCl-sago RS
samples were 14.9% and 1.94 g/g, respectively, which were lower than that of sago
RS (27.4% and 2.82 g/g, respectively). Sago RS and HCl-sago RS samples were
resistant to 180 min hydrolysis by gastric acidity at pH 1 to 4 with less than 0.85%
hydrolyzed. Both samples were also resistant toward hydrolysis by gastrointestinal
tract enzymes and intestinal absorption with 96.8% and 98.7% of RS3 were recovered
respectively after 3.5 h digestion and overnight dialysis at 37 °C. Sago RS and HClsago
RS acted selectively, by increasing the growth of rat intestinal bacteria (lactobacilli and bifidobacteria) while decreasing the growth of detrimental
bacteroides, clostridia and enterobacteria. The prebiotic indexes of sago RS, HClsago
RS, oligofructose and inulin were +12.19, +4.75, +9.45 and +6.82, respectively.
Butyric acid production by rat faecal culture was higher in media with Sago RS and
HCl-sago RS than with oligofructose and inulin. The activity of β-glucuronidase
were reduced by sago RS and HCl-sago RS. Contrary, native sago starch supported
the growth of both beneficial and detrimental bacteria. Sago RS and HCl-sago RS
were the better growth substrate for Lactobacillus plantarum FTCC0350 as
compared with FOS and inulin. Lactic and acetic acid production by Lactobacillus
plantarum FTCC0350 was higher in media with sago RS and HCl-sago RS. In
conclusion, sago RS and HCl-sago RS exhibited prebiotic characteristic and they are
potential prebiotic
Description
Keywords
Sago (Metroxylon sagu)