Stability Modeling of Red Pigments Produced by Monascus purpureus in Submerged Cultivations with Sugarcane Bagasse

Abstract

Monascus purpureus red pigments were produced in submerged cultivations employing sugarcane bagasse (SB) as carbon source in combination with various nitrogen sources. Peptone and soy protein isolate (SPI) as nitrogen sources generated the best pigment yields. NH4Cl has not supported high pigment production. Red pigments produced using SB and SPI as growth substrates were submitted to temperature and pH stability analysis. Data from thermal pigment degradation were fitted to five mathematical models, and a first-order equation was accepted as the best one to describe color decay. Red pigments showed high stability at low temperatures (30–60 °C) and at near-neutrality pH values (6.0–8.0) when compared to that at high temperatures (above 60 °C) and at acidic pH values (4.0–5.0). Monascus pigments produced using a low-cost agroindustrial waste (SB) as carbon source could be utilized as colorants in foods and foodstuffs manufactured under mild process conditions.