Effect of Different Processing Methods (Roasting and Shade- Drying) on Fatty Acid Profile of Tumeric (Curcumin longa)

Abstract

Temperature has been identified as an important factor affecting the fatty acid
composition in food products. The study assessed the effect of roasting and
shade-drying on the fatty acid profile of turmeric (Curcumin longa). Two
kilograms of freshly harvested turmeric were purchased from a local market in
Nsukka LGA, Enugu State, Nigeria. Three samples coded A, B and C were used
for the study. Samples A and B were subjected to roasting and shade-drying,
respectively, while C was untreated and served as a control. Turmeric oil from
these samples was extracted and taken to the laboratory for analysis. Standard
methods were used for the oil extraction and analysis. Data obtained were
analysed statistically using Statistical Product and Service Solution (SPSS)
version 22. Analysis of variance (ANOVA) was used to compare means while
Turkey HSD-test was used to separate means. Statistical significance was set at
p < 0.05. The results showed that shade-dried and roasted turmeric had higher
(p < 0.05) unsaturated fatty acid (2.51 and 2.03 mg), respectively than fresh
turmeric (0.53 mg). The total omega-3 fatty acid (1029.93 mg) in the shade-dried
and 720.72mg in the roasted samples was higher than that in the fresh sample.
The fatty acid profile result revealed that the roasted sample contained the
highest amount of oleic acid (43.65 g) while the shade-dried samples had the
highest amount (44.14g) of palmitic acid. Therefore, shade-drying and roasting
increased the unsaturated fatty acids, polyunsaturated fatty acids (omega-3 and
omega-6) and some of the fatty acid profiles of turmeric oil