Rheological properties of aqueous dispersions of OKRA (Abelmoschus esculentus) GUM

Ain Nadiah Sofiah Ahmad Khorairi, Noor Soffalina Sofian Seng, Nurul Shahirah Aziz, Nur Ain Nabila Azali, Khairul Farihan Kasim, Noorul Syuhada Mohd Razali

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

This study aims to characterise the rheological properties of okra (Abelmoschus esculentus) aqueous dispersion. Okra gum was extracted by water extraction and was freeze dried before reconstituting to the desired concentration. Proximate analysis of freeze-dried okra gum showed that the major constituent is carbohydrate (84%) and some protein (6%). The effect of mucilage concentration (0.25-1%), pH (3-8) and ionic strength (0-0.2 M) on the rheological properties was also evaluated. Okra gum dispersion exhibited shear-thinning characteristic. Apparent viscosity increased as the okra gum concentration increased. Okra gum concentration had an increasing trend towards k (consistency index), whereas ionic strength and pH displayed no apparent trend. Generally, within the frequency range tested, the okra gum dispersion’s storage modulus (G’) were larger than the loss modulus (G”), except for dispersion with 0.15M NaCl which had a crossover of G’ and G” at higher frequency. However, the gum dispersion was relatively insensitive to ionic strength as the apparent viscosity was within a limited range. Okra gum dispersion at pH 8 resulted in much higher G’ and G” compared to the other pH. Thus, okra gum can be potentially used as food thickener, although it can be influenced by the pH of the food medium.

Original languageEnglish
Pages (from-to)189-196
Number of pages8
JournalMalaysian Applied Biology
Volume47
Issue number5
Publication statusPublished - 1 Nov 2018

Fingerprint

Abelmoschus
Abelmoschus esculentus
rheological properties
ionic strength
water
Osmolar Concentration
viscosity
Viscosity
loss modulus
okra
okra gum
storage modulus
mucilages
Food
proximate composition
shears
Gingiva
carbohydrates

Keywords

  • Aqueous dispersion
  • Mucilage
  • Okra gum
  • Rheology

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

Cite this

Rheological properties of aqueous dispersions of OKRA (Abelmoschus esculentus) GUM. / Khorairi, Ain Nadiah Sofiah Ahmad; Sofian Seng, Noor Soffalina; Aziz, Nurul Shahirah; Azali, Nur Ain Nabila; Kasim, Khairul Farihan; Mohd Razali, Noorul Syuhada.

In: Malaysian Applied Biology, Vol. 47, No. 5, 01.11.2018, p. 189-196.

Research output: Contribution to journalArticle

Khorairi, Ain Nadiah Sofiah Ahmad ; Sofian Seng, Noor Soffalina ; Aziz, Nurul Shahirah ; Azali, Nur Ain Nabila ; Kasim, Khairul Farihan ; Mohd Razali, Noorul Syuhada. / Rheological properties of aqueous dispersions of OKRA (Abelmoschus esculentus) GUM. In: Malaysian Applied Biology. 2018 ; Vol. 47, No. 5. pp. 189-196.
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