The effect of genotype and roasting on the fatty acid composition of peanuts

Abstract

The impact of two factors, genotype (G) and treatment (raw or roasted peanut) (T), on the chemical composition of peanuts was studied using a chemometric method and Tukey's test. The peanut genotypes evaluated were cultivar cavalo vermelho (CCV), cultivar cavalo rosa (CCR) and cultivar tatu (CTA), in both raw and roasted states. The total lipid contents in the CTA and CCR peanuts were 40 and 45%, respectively. These values did not vary significantly (P<0.05) after roasting. CCV had the greatest total lipid content, but it decreased significantly after roasting (from 50% to 45%). The variation in the percentage of lipids in the CCV and CCR genotypes was not significant, in contrast to the CTA genotype. The fatty acid (FA) 18:1n−9 predominated in the CCR and CCV samples (50%), without any difference between their raw genotypes. The values for FA 18:1n−9 were lower in the CTA peanut (40%). The second most abundant FA was 18:2n−6 (CCV=28%, CTA=38% and CCR=25%), followed by 16:0 (CCV and CCR=16% and CTA=11%). The other FAs found in the peanuts were 18:0, 20:0, 22:0, 24:0, 20:1n−9 and 18:3n−3. The contents of FAs 18:1n−9, 16:0, 20:0, and 20:1n−9 suffered significant reduction after roasting in all genotypes. ANOVA analysis of the influence of the main factors indicated that the contribution of the T variable for the majority of responses was low, being between 0.2 and 13%, except for FAs 16:0 and 18:3n−3 and for the saturated FA summations, which were 38, 60 and 22%, respectively. There was a significant contribution from the G factor for all responses, with values between 17 and 99%. The contribution of the interaction between the T and G factors was greater for the responses n6/n3 (56.6%) and for the FA 16:0 (23%). The other responses had values between 0.02 and 14%.