Abstract
Due to its high nutritional value and
health-promoting effects, there is an increasing interest in utilizing chia
seed in the human diet. The aim of this study was to compare the compositional
and functional characteristics of white and black chia seeds that are
commercially available in Turkey. Compositional comparisons were done by
quantifying protein, oil, ash and moisture contents. The total phenolic content
and antioxidant activity were measured using defatted ground chia seeds. Our
results revealed that black chia seeds had significantly higher protein, ash
and moisture contents, compared to white chia seeds, but no difference was
found in terms of oil content (P > 0.05). Conversely, the total phenolic
content of white chia seeds (3.52 ± 0.08 mg GAE [gallic acid equivalent]/g sample) was
significantly higher than those in black seeds (3.42 ± 0.06 mg GAE/g sample) (P < 0.05). Consequently, a significant
difference (P < 0.05) was observed between DPPH free radical scavenging
activities of white and black chia seeds, with the former exhibiting 231.5 ± 6.3 mmol Trolox equivalent (TE)/g, and the latter having 197.5 ± 7.4 mmol TE/g. The higher antioxidant activity of white chia seed was further
confirmed by calculating IC50 values (IC50 of black chia
seed = 2.001 mg/ml vs that of white chia seed = 1.735 mg/ml). Finally, we
assessed antibacterial activities of chia seed extract and chia seed oil
against human pathogens using agar
disc-diffusion and agar well-diffusion assays. However, neither of the assays
had shown antimicrobial activity against the tested bacteria. Considering the
previously published reports, chia seed and chia seed oil seem to
possess species-, and even strain-, specific antimicrobial activities. Overall,
the results of this study suggest that white chia seed has better functional
properties than black seeds.