RESEARCH ARTICLE

Journal of Oil Palm Research Vol. 33 (4) December 2021, p. 668-677

OPTIMISATION OF ALKALI EXTRACTION OF PALM KERNEL CAKE PROTEIN

FATAH YAH ABD MANAF* and NOOR LIDA HABI MAT DIAN*

DOI: https://doi.org/10.21894/jopr.2021.0011
Received: 24 June 2020   Accepted: 29 January 2021   Published Online: 1 April 2021
ABSTRACT

Palm kernel cake (PKC) is commonly used in animal feed, particularly as ruminant feed to supply protein and energy. There is little information on the properties of protein concentrate produced from the PKC which constitute 14%-17% of the meal. Protein concentrates can be produced from PKC using alkali extraction, where PKC is extracted with an alkali solution and followed by precipitation at the isoelectric point. Thus, this study examined the effects of extraction using several extractants at different conditions; meal ratio of 0.5:50-3.0:50 g ml–1, concentration of 0.1-1.0 M, pH 1-12, temperature of 30°C-80°C and time duration of 30-180 min. Sodium hydroxide (NaOH) was found to be the most suitable alkali for protein extraction. Optimum conditions for protein extraction were obtained at 1.0 M NaOH concentration, 50°C temperature, meal to solvent ratio of 2:50 (g ml–1), pH 12 and 120 min. The extracted protein was isolated by isoelectric precipitation at pH 3.5 using 1.0 M hydrochloric acid (HCI). The percentage of protein recovery was 80%-86%. Protein content in the recovery ranged from 45%-50%. Analysis by high performance liquid chromatography (HPLC) showed that arginine, glutamic acid, phenylalanine and leucine were the most abundant amino acids in the concentrates.

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* Malaysian Palm Oil Board,
6 Persiaran Institusi, Bandar Baru Bangi,
43000 Kajang, Selangor, Malaysia.

* Corresponding author e-mail: fatahyah@mpob.gov.my