Safe natural bio-pigment production by Monascus purpureus using mixed carbon sources with cytotoxicity evaluation on root tips of Allium cepa L.

By increasing the undesirable side effects of synthetic food pigments on human health, using safe natural food pigment become an urgent issue. Incorporate corn starch with oils conducted a high impact on red pigment production by Monascus purpureus. Fortification the medium with sesame oil raised the pigment production by 80% and the dry mass by 63% compared with free oil medium. Response surface methodology maximizes the production with 114.6% (12.8 A500) using medium constituents (g/l); Sesame oil 5; Corn starch 30; Yeast extract 1.5; KH2PO4 2.5 and MgSO4.7H2O 0.1. After evaluating red pigment stability in three common food components, citric acid showed a great effect on residual stability percentage compared with ascorbic and salicylic acid which decrease slightly the residual stability percentage at light and dark conditions. The mitotic index of red pigment was lower than the negative control at all tested concentrations. Different types of mitotic chromosomal abnormalities e.g. lagging chromosome, chromosomal bridge, chromosome and chromatin fragments, outside chromosome, chromosomal stickiness and micro nuclei were recorded. Insignificant increase in total mitotic aberrations percentage in all tested root tips treated with all concentrations of red pigment (1.23, 1.58, 1.63, 2.32 and 2.40%) compared with negative control (0.91%). There was a significant increase in total aberrations percentage after treatment with all concentrations (10, 15, 20 and 25%) of positive control (2.93, 3.00, 3.55 and 6.53 respectively) except (5%) which was insignificant (2.71%). From the previous data, this red pigment can be used as an alternative safe pigment in the food industry. © Association of Food Scientists & Technologists (India) 2020.