L. Sulandari, T. Utami, C. Hidayat, E.S. Rahayu
Monascus purpureus, a species of red filamentous mould, has been widely used in fermented food as a potential source of natural pigments. The pigments can be produced by solid-state fermentation using a solid culture substrate; an example includes cheese that provides a substantial amount of nutrients required for its growth and red pigment synthesis. Monascus purpureus needs appropriate organic nitrogen in the form of amino acids at a particular concentration. This study aimed to determine the effects of methionine level on cheese colour as the solid substrate in M. purpureus fermentation. The mould strain M. purpureus JK2 was cultivated from cheese without the addition of methionine and added with 0.1, 0.3, 0.5, and 1% methionine, then incubated at room temperature (25‒30°C) for 14 days. The growth of M. purpureus JK2 in cheese as a solid substrate was visually observed. Colour changes were distinguished quantitatively based on the CIELAB colour characterization system. The results showed that M. purpureus JK2 could grow and synthesize red pigments well in cheese as a substrate without the addition of methionine, which otherwise slowly decreased (0.1, 0.3 and 5% methionine) and inhibited the growth (1% methionine). The cheese substrate without the addition of methionine had a similar hue angle to 0.1 and 0.3% methionine and was relatively redder than with 0.5% methionine. However, the addition of 1% methionine did not induce pigmentation. Furthermore, the M. purpureus JK2-fermented cheese as a substrate can be used in cheese making development as culture products. © 2022 The Authors.
Department of Food and Agricultural Product Technology, Faculty of Agricultural Technology, Universitas Gadjah Mada, Jl. Flora No.1 Bulaksumur, Yogyakarta, 55281, Indonesia; Department of Home Economics, Engineering Faculty, Universitas Negeri Surabaya, Jl. Ketintang, Surabaya, 60231, Indonesia; Center for Food and Nutrition Studies, Universitas Gadjah Mada, Jl. Teknika Utara, Sleman, Yogyakarta, 55281, Indonesia
