CJFST.2020.12.1.02

Original scientific paper                                                                                                                                                      DOI: 10.17508/CJFST.2020.12.1.02

Nutritional profile, protein quality, and biological value of raw and roasted cashew kernels (Anacardium occidentale) grown in southwest Nigeria

OLAWALE PAUL OLATIDOYE1, TAOFIK AKINYEMI SHITTU2, SAMUEL OLUSEGUN AWONORIN3, EMMANUEL SUNDAY AKIN AJISEGIRI4

1Department of Food Technology, Yaba College of Technology, P.M.B 2011, Yaba, Lagos state, Nigeria
2,3Department of Food Science and Technology, Federal University of Agriculture, P.M.B 2240 Abeokuta, Ogun state, Nigeria
4Department of Agricultural Engineering, Federal University of Agriculture, P.M.B 2240, Abeokuta, Ogun state, Nigeria

ARTICLE INFO ABSTRACT
Article history:
Received: May 5, 2019
Accepted: November 23, 2019
Cashew kernels are one of the most concentrated food products due to their fat and protein content and they are used in puddings and bakery products, hence the determination of their protein quality is an important nutritional factor in dietary protein requirements. Therefore, the study aimed at evaluating the effect of roasting conditions on the protein quality of cashew kernels at the temperature of 100–160 °C and time (20–60 min), and then analysing for the amino acid profile by GC-FID; protein predicted efficiency ratio (P-PER), essential amino acid index (EAAI), and the Isoelectric point (pI). About 2.0 kg of dried cashew kernels used were defatted using chloroform/methanol (2:1/v/v) as the extraction solvent and then analysed using standard methods. The results showed that seventeen amino acids were present in cashew nuts, where glutamic acid (15.27g/100gN); aspartic acid (12.20g/100gN); lysine (6.09g/100g N), and phenylalanine (5.06g/100g N) were predominant. Eight essential amino acids were present in cashew kernels, the highest value of 7.33g/100g were for lysine (6.09g/100gN); 1.70g/100gN (histidine); 3.42g/100gN (threonine); 3.63g/100gN (valine); 3.57 g/100gN (isoleucine); 7.33g/100gN (leucine); and 5.06g/100gN (phenylalanine). Roasting reduced the lysine content by 18.4%, phenylalanine by 12.06%, and aspartic acid by 41.4% at 160°C for 60 min, while serine (58.9%); glutamic acid (19.7%); arginine (47.4%), and histidine (115.9%) were increased, suggesting that cashew nuts contain high quality protein. P-PER results were 2.57 (raw), 171-2.61 (roasted); EAAI is 1.55(raw) and 1.38-1.55 (roasted), BV% is 76.15 (raw) and 67.61-76.89 (roasted); the Isoelectric points were 4.65 (raw) and 3.87- 4.54 (roasted), The Leu/Ileu ratio was 2.12 (raw) and 2.01-2.67 (roasted). It was concluded that the heat treatment used does not significantly affect the amino acid profile of cashew kernels, thus preserving their nutritional quality.
Keywords:
cashew nut
roasting
amino acid
predicted protein efficiency ratio
essential amino acid index