Supercritical carbon dioxide extraction of lutein from yellow maize (Zea mays) kernels: process optimization based on lutein content, antioxidant activity, and ω-6/ω-3 fatty acid ratio

Abstract

Yellow maize kernels were subjected to supercritical carbon dioxide (SC-CO) extraction to obtain a lutein-rich extract with potential nutraceutical properties. SC-CO extraction parameters (pressure and temperature) were optimized by employing a full-factorial (3) design of experiments and response surface methodology, based on yield of lutein, antioxidant activity, and ω-6/ω-3 fatty acid ratio of the extracts. A Chrastil equation was also developed for predicting the solubility of lutein in SC-CO under different extraction conditions. The optimized extraction condition was obtained at 500 bar, 70 °C for 90 min, at which the extract was found to possess a unique combination of the highest lutein yield (275.00 ± 3.50 μg/g of dry weight), along with a well-balanced ω-6/ω-3 fatty acid ratio (3:1). Moreover, the total phenol content and antioxidant activity were also found to be the highest at this condition. This lutein-rich extract is a promising nutraceutical or dietary supplement in the food industry.

Lutein‐fortified potato soup and freeze‐dried lutein powder designed with supercritical carbon dioxide extract of yellow corn kernels are promising nutraceutical foods

“…The details of the extraction methodology including statistical optimization of the extraction conditions (w.r.t. highest yield of lutein and maximum antioxidant activity of the extract) has been described in our previous publication on SC-CO 2 extraction of lutein from yellow maize kernels (Pal & Bhattacharjee, 2017a).…”

“…Therefore, it could be concluded that, 120‐day stored γ ‐irradiated corn grits resulted in yielding significantly ( p < 0.05) higher amount of lutein, compared to the “fresh” kernels (lutein content: 275 ± 1.16 µg/100 g [d.b.]) (Pal & Bhattacharjee, ), which could be attributed to “carotenogenesis” in the former. Eventually, this extract also possessed significantly ( p < 0.05) higher biochemical potencies such as improved antioxidant activity (IC 50 : 3.17 ± 0.11 mg/ml, FRAP value: 478.67 ± 2.84 mM equivalent FeSO 4 /g [d.b.]…”

“…corn kernels), compared to those obtained from control (“fresh” kernels) set (IC 50 value: 3.85 ± 0.17 mg/ml, FRAP value: 402 ± 3.99 mM equivalent FeSO 4 /g dry corn kernels) (Pal & Bhattacharjee, ) under similar extraction conditions. Furthermore, FAME‐GC‐FID analysis ( Figure ) of fatty acid revealed that this extract had a desirable balanced ratio (3.47:1.00) of ω‐6/ω‐3 fatty acids close (3:1) to that of the extract of “fresh” corn grits (Pal & Bhattacharjee, ) and much improved than the same (60:1) in corn oil, which reportedly has adverse health consequences. An optimal ration of ω‐6/ω‐3 PUFAs is 2:1 and more specifically 4:1 for the Indian population (Sen, 2011‐2012).…”

“…Lutein content of the extract obtained from “preserved” corn grits was ascertained by HPLC‐PDA analysis (Bhattacharyya et al, ). Besides, biochemical analyses such as DPPH radical scavenging activity (RSA) expressed as IC 50 value (which refers to the minimum concentration of the extract required to scavenge DPPH radicals by 50%, that is, the lower the IC 50 value of the extract, the greater will be its antioxidant activity) (Mahakunakorn, Tohda, Murakami, Matsumoto, & Watanabe, ; Spanos & Wrolstad, ), antioxidant activity by ferric reducing antioxidant power (FRAP) assay (Benzie & Strain, ) along with evaluation of ω‐6/ω‐3 fatty acids ratio (since the extracts may contain oil ) (Pal & Bhattacharjee, ) were also carried out for the same. These assays were conducted with three independent batches of SC‐CO 2 extracts (obtained from three independent experimental runs) and reported as mean ± SD .…”

“…These assays were conducted with three independent batches of SC‐CO 2 extracts (obtained from three independent experimental runs) and reported as mean ± SD . Lutein content and other biochemical characteristics of the SC‐CO 2 extract of “fresh” corn grits can be found in the publication by Pal and Bhattacharjee (). The extract obtained from “fresh” corn grits at optimized condition is designated as “CE best ” and that of “preserved” samples is nomenclatured as “i‐CE best .”…”