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Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties

Physicochemical properties of pigeonpea and cowpea protein isolates were determined as a function of extraction technique and pH of the extracting medium. Protein extractability by the isoelectric point precipitation (IP) technique was positively correlated within the pH of the NaOH solution used in...

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Main Authors: Mwasaru, Mwanjala A., Muhammad, Kharidah, Bakar, Jamila, Che Man, Yaakob
Format: Article
Language:English
Published: Elsevier Science 1999
Online Access:http://psasir.upm.edu.my/id/eprint/114406/1/114406.pdf
http://psasir.upm.edu.my/id/eprint/114406/
https://linkinghub.elsevier.com/retrieve/pii/S0308814699001508
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spelling my.upm.eprints.1144062025-02-05T03:48:42Z http://psasir.upm.edu.my/id/eprint/114406/ Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties Mwasaru, Mwanjala A. Muhammad, Kharidah Bakar, Jamila Che Man, Yaakob Physicochemical properties of pigeonpea and cowpea protein isolates were determined as a function of extraction technique and pH of the extracting medium. Protein extractability by the isoelectric point precipitation (IP) technique was positively correlated within the pH of the NaOH solution used in the pH range 8.5-12.5. The micellization (MP) technique extracted significantly (P < 0.05) less protein than the IP technique when extraction pH of the NaOH was 9.5 or higher, and 10.5 or higher from cowpea and pigeonpea, respectively. The subunit composition and electrical mobility of the isolates were not affected by extraction technique and pH conditions. However, it was observed that the IP isolate extracted at pH 12.5 had the lowest proportion of hydrophilic amino acids, suggesting that the pH of the extracting medium exerted a major influence on the hydrophilicity of the isolates. Pigeonpea MP isolate exhibited significantly (P < 0.05) higher exposed hydrophobicity than the IP isolates except for those extracted at pH 9.5 and 10.5. However, the cowpea MP isolate exhibited significantly lower exposed hydrophobicity than the IP isolate extracted at pH 8.5 but this was higher than the rest of the IP isolates. For IP isolates, an inverse relationship was apparent between the extraction pH and hydrophobicity. The MP isolates from both legume seeds were significantly lighter in colour than the corresponding IP isolates and, for the latter, the lightness value (L) was inversely correlated with extraction pH. Differential scanning calorimetry showed that the MP isolates exhibited higher transition enthalpy (ΔH) than the IP. For the IP isolates, ΔH decreased with increasing extraction pH. Elsevier Science 1999 Article PeerReviewed text en http://psasir.upm.edu.my/id/eprint/114406/1/114406.pdf Mwasaru, Mwanjala A. and Muhammad, Kharidah and Bakar, Jamila and Che Man, Yaakob (1999) Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties. Food Chemistry, 67 (4). pp. 435-443. ISSN 0308-8146; eISSN: 0308-8146 https://linkinghub.elsevier.com/retrieve/pii/S0308814699001508 10.1016/S0308-8146(99)00150-8
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description Physicochemical properties of pigeonpea and cowpea protein isolates were determined as a function of extraction technique and pH of the extracting medium. Protein extractability by the isoelectric point precipitation (IP) technique was positively correlated within the pH of the NaOH solution used in the pH range 8.5-12.5. The micellization (MP) technique extracted significantly (P < 0.05) less protein than the IP technique when extraction pH of the NaOH was 9.5 or higher, and 10.5 or higher from cowpea and pigeonpea, respectively. The subunit composition and electrical mobility of the isolates were not affected by extraction technique and pH conditions. However, it was observed that the IP isolate extracted at pH 12.5 had the lowest proportion of hydrophilic amino acids, suggesting that the pH of the extracting medium exerted a major influence on the hydrophilicity of the isolates. Pigeonpea MP isolate exhibited significantly (P < 0.05) higher exposed hydrophobicity than the IP isolates except for those extracted at pH 9.5 and 10.5. However, the cowpea MP isolate exhibited significantly lower exposed hydrophobicity than the IP isolate extracted at pH 8.5 but this was higher than the rest of the IP isolates. For IP isolates, an inverse relationship was apparent between the extraction pH and hydrophobicity. The MP isolates from both legume seeds were significantly lighter in colour than the corresponding IP isolates and, for the latter, the lightness value (L) was inversely correlated with extraction pH. Differential scanning calorimetry showed that the MP isolates exhibited higher transition enthalpy (ΔH) than the IP. For the IP isolates, ΔH decreased with increasing extraction pH.
format Article
author Mwasaru, Mwanjala A.
Muhammad, Kharidah
Bakar, Jamila
Che Man, Yaakob
spellingShingle Mwasaru, Mwanjala A.
Muhammad, Kharidah
Bakar, Jamila
Che Man, Yaakob
Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties
author_facet Mwasaru, Mwanjala A.
Muhammad, Kharidah
Bakar, Jamila
Che Man, Yaakob
author_sort Mwasaru, Mwanjala A.
title Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties
title_short Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties
title_full Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties
title_fullStr Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties
title_full_unstemmed Effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (Cajanus cajan) and cowpea (Vigna unguiculata) protein isolates. I. Physicochemical properties
title_sort effects of isolation technique and conditions on the extractability, physicochemical and functional properties of pigeonpea (cajanus cajan) and cowpea (vigna unguiculata) protein isolates. i. physicochemical properties
publisher Elsevier Science
publishDate 1999
url http://psasir.upm.edu.my/id/eprint/114406/1/114406.pdf
http://psasir.upm.edu.my/id/eprint/114406/
https://linkinghub.elsevier.com/retrieve/pii/S0308814699001508
_version_ 1823276360275066880
score 13.239859

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