Development of technique and nondestructive measuring instrument to evaluate vegetables and fruits maturity based on fluorescence measurement

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K05913
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 41040:Agricultural environmental engineering and agricultural information engineering-related
• Research Institution: Kisarazu National College of Technology
• Principal Investigator: Fukuchi Ken'ichi 木更津工業高等専門学校, 基礎学系, 教授 (00218942)
• Co-Investigator(Kenkyū-buntansha): 嘉数 祐子 (大野祐子) 木更津工業高等専門学校, 基礎学系, 准教授 (30455117)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 蛍光スペクトル / 熟度 / 非破壊計測 / 果実

Outline of Final Research Achievements

In this study, we developed a non-destructive technique to evaluate fruit maturity based on fluorescence measurement. We excited fruits using a light wavelength of 620 nm and measured the fluorescence spectra emitted from the inside of the fruit. The fluorescence maturity index (FMI), which is defined as the logarithm of F685/F740, was used for the evaluation. Here, F685 and F740 were the chlorophyll-a fluorescence intensity at 685 and 740 nm, respectively.
We ripened mature-green tomatoes and examined the relationship between FMI and chromaticity. We clarified that FMI began to increase several days before changes in chromaticity. Experimental results on kiwi fruits revealed that the FMI changes differed greatly depending on the ripening temperature, and there were good linear correlations between FMI and fruit firmness as well as between FMI and sugar/acid ratio. It is thought that this technique can be effectively applied to judge the shipment time and edible period of fruits.

Free Research Field

光応用計測

Academic Significance and Societal Importance of the Research Achievements

果実は追熟により品質が大きく変化し，品質管理が難しいうえ，熟度により食味評価が大きく異なるため，消費者が食べ頃に口にすることが難しいという問題がある。本研究の成果により，果実内部から放出される蛍光の測定に基づき，非破壊で熟度を評価できるようになり， 勘と経験に頼っていた果実の品質管理や食べ頃の判断を客観的に行うことが可能となった。本手法は，果実の流通の適正化及び消費の活性化に大きく貢献できると考えられる。