Rice quality amylose tester successfully developed through the 948 Program
To fundamentally improve the current rice quality, namely the amylose content of rice, in 2001 the Ministry of Agriculture included the "Rice Quality Amylose Tester" project in the "948" Program. Organized and implemented by China Agricultural University, the project aimed to develop, through this research, a high-quality paddy quality testing instrument suitable for all stages and all levels. Under the leadership of project leader Professor Jia Guiru, Director of the Department of Applied Physics at China Agricultural University, the project has now been completed and has achieved remarkable results.
It is reported that the rice quality amylose tester consists of a computer, a 60-position autosampler, an 8-channel peristaltic pump, an amylose module, an automatic gas-liquid separator, and a fiber-optic dual-beam automatic photoelectric colorimeter. It uses a 635nm semiconductor laser as a monochromatic light source, along with software for computer communication and computer feedback control functions; its detection accuracy and detection speed reach the international advanced level, and its degree of automation is high, making it suitable for quality inspection centers at the county level and above. For the economical "Rice Quality Amylose Tester," the instrument consists of a single-chip microcontroller, a non-powered autosampler, a display, and a fiber-optic dual-beam automatic photoelectric colorimeter, and can display and print data. The instrument's detection accuracy reaches the international advanced level, and its detection speed is one sample every two minutes. The project has filed patents for two items: the "non-powered autosampler" and the "18-microliter color development cell." Among them, the 18-microliter color development cell reaches the international advanced level.
During research and testing, Professor Jia Guiru discovered that the higher the amylose content of a rice sample, the darker the color of the sample liquid after color development; the lower the amylose content of a rice sample, the lighter the color of the sample liquid after color development. Based on this phenomenon and knowledge of colorimetry, a completely new detection method based on colorimetry was proposed, namely the "digital colorimetry detection method." Theoretically, the detection accuracy of the digital colorimetry detection method should be no lower than that of the spectrophotometric method, and the detection speed of the digital colorimetry detection method can be more than 100 times faster than that of the spectrophotometric method.
Professor Hou Caiyun of the research group also applied the digital colorimetry detection method to the detection of rice amylose content. At the 2003 appraisal meeting organized by the Ministry of Education for the "Tenth Five-Year Plan" key project "Rapid Detection System for High-Quality Paddy Quality," the rapid detection method using digital colorimetry to detect rice amylose content was considered to have international leading level, with detection accuracy the same as the current standard method.
In March 2004, inferior milk powder appeared in China. Using the digital colorimetry detection method to quantitatively detect the protein content of milk powder required 40 minutes. However, determining whether the protein content of milk powder was qualified required only 2 minutes. In June 2004, the Ministry of Education organized an appraisal of the rapid detection system for milk powder protein. The rapid milk powder protein detection system developed by the project is suited to China's national conditions, filled a domestic gap, and its overall technology holds a leading domestic position, while the application of digital image recognition technology to milk powder protein detection reaches the international advanced level.
The "digital colorimetry detection method" has advantages such as low cost, high accuracy, and high speed, and theoretically it is entirely possible for it to become a universally applicable, completely new detection method. The success of using the digital colorimetry detection method in detecting rice amylose and protein content and milk powder protein content has greatly encouraged the research group and strengthened its confidence in further developing and improving the digital colorimetry detection method. The research group will strive to spend another 1-2 years to perfect the digital colorimetry detection method into a universally applicable detection method, partially replacing the spectrophotometric method.