Abstract
英文摘要Monascus pigments are traditional natural food colorants in oriental countries. They are a mixture of yellow (monascin, ankaflavin), orange-red (rubropunctatin, monascorubrin) and red-purple (rubropunctamine, monascorubramine) compounds. Traditionally, solid-state culture is employed for Monascus species. The microorganisms are normally cultivated on steamed rice grains and proper temperature and humidity have to be maintained throughout the whole process. Hence, it is difficult to control the process parameters and to keep the cultivation process from contamination in a large-scale production. Consequently, the quality of the products is difficult to maintain. On the contrary, even though the capital investment involved for the submerged cultivation process is greater than that for the solid state cultivation, one can better control the process parameters and take advantage of the more flexible processing conditions. The products from the submerged cultivation process are expected to be purer and more uniform. However, the amount of products produced by solid-state fermentation is greater than that produced by submerged fermentation (Lin, 1982). This might be related to the composition and microstructure of the rice (Johns and Stuart, 1991).In this research, a combined process utilizing the advantages of both submerged and solid state cultivation was developed. The solid state cultivation was proceeded in a 5 L fermentor, while rice was employed not only as the substrate but also as the support for Monascus. To integrate the fermentation and separation of the red pigments, one intermittently rinsed the rice with monosodium glutamate solution every 12 hours to wash out the resulting red pigments. An adsorption column was employed to adsorb the red pigments in the MSG solution and the MSG solution was recycled. The result showed that, the amount of Monascus red pigments produced by the integration system is 20% more than that produced by the fixed-bed cultivation.