Research on colour improvement of paper-making reconstituted tobacco
Paper-making reconstituted tobacco (PRT) is an important raw material for the tobacco industry, with various benefits including reducing cost, smoke tar delivery, and impact on the environment. The different appearance of PRT compared to regular cigarette tobacco blend has been observed by the consumer. In this study, a method with a colorimeter was developed for the measurement of colour difference. Some key technical methods were taken to reduce the colour difference, such as modifying the coating ratio and the level of calcium carbonate and using concentrated liquid after Maillard reaction. The effect of storing environment on the colour of PRT was also studied. The results showed that: a) with the increase of coating rate, the colour of PRT grew darker and became closer to the colour of cigarette tobacco blend; b) the increase of calcium carbonate makes PRT lighter; c) adding concentrated liquid after Maillard reaction is a very important and useful method to narrow the colour difference between PRT and cigarette tobacco blend without adding any other additives; and d) the colour of PRT is influenced by such factors as storage time, temperature and humidity. The impact of storage conditions is small, therefore, conventional storage conditions can satisfy the requirements of PRT. In conclusion, this study provides a science-based understanding of the colour differences between PRT and cigarette tobacco blends, and practical approaches to resolve the issue.