Analysis and automation to remove the astringency of persimmons

本研究的目的是提高柿子脱涩的质量，降低成本。研究了二氧化碳浓度、温度和处理时间与柿果内外品质的关系。在此基础上，开发了一套工艺试验系统，该系统具有较高的试验效率. (1)柿子反应的性质-在40摄氏度下，随着温度和二氧化碳浓度的增加，处理时间呈指数下降。(2)软化效果-一种新的加工方法，保持温度和湿度分别在35度和95%，缩短了六分之一的处理时间，与传统的方法，保持在25度和90%。另一方面，温度升高10度导致呼吸速率加倍。然而，由于处理持续时间减少，累积呼吸保持一半。以上因素均抑制了柿果的软化。(3)柿子颜色的变化-一个早期收获的柿子看起来绿色黄褐色。这种颜色在高温处理后变成黄褐色。说明高温处理对延长采收期是有效的。(4)试验系统的设计-本研究的结果在三年内和其他一些参考澄清了最佳条件，以消除涩的柿子。利用这些新知识，研制了一套脱涩试验系统。该系统设计成在容量为0.8t的容器内置换空气并填充二氧化碳。该系统能有效地防止煤气泄漏，节约煤气消耗。此外，该系统是有效的气体浓度和温度均匀的容器内。

Objective of this research is a qualitative improvement and lowering cost of a process to remove the astringency of persimmons. A relationship among inside or outside quality of persimmon, carbon dioxide concentration, temperature and processing duration was clarified. Then a test system for the process was developed The system showed high efficiency.(1) Property of a persimmon reaction - The processing duration decreased exponentially under forty degree centigrade with an increase of temperature and carbon dioxide concentration.(2) Effect on softening - A new processing method which maintained temperature and humidity at 35 degree and 95% respectively shortened the processing duration by one-sixth, comparing with a conventional method which kept them at 25 degree and 90%. On the other hand, the 10 degree raising of temperature caused a respiration rate double. However, an accumulated respiration remained by one-half because the processing duration decreased. The above factors prevented from softening of persimmon.(3) Change of persimmon color - An early-harvested persimmon looked green yellowish brown. This color changed to yellowish brown after the high temperature processing. This result showed that the high temperature processing would be effective for extending harvesting period.(4) Design of the test system - The results of this study during three years and some other references clarified an optimum condition to remove the astringency of persimmons. Using the new knowledge, a test system for the removing the astringency was manufactured. This system was designed so as to replace the air and fill carbon dioxide inside a container whose capacity was 0.8 t. This system prevented from leaking gas and then effective for saving gas consumption. Furthermore this system was effective for uniformity of gas concentration and temperature inside the container.