Abstract: The effects of the treatment of young fruits with 20 mg/L of 1-(2-chloropyridin-4-yl)-3-phenylurea (CPPU) and mass loss during room-temperature storage on the quality and electrical characteristics of two kiwifruit varieties, ‘Qinmei’ and ‘Hayward’ were investigated. Results showed that CPPU treatment and mass loss during storage could lead to a significant decline in fruit quality. For ‘Qinmei’ and ‘Hayward’ kiwifruits, the greatest impact came from mass loss and CPPU treatment, respectively. Out of 24 frequencies tested, 3 980, 2 510, 251 and 631 kHz were selected respectively as the characteristic frequencies for CPPU treated and untreated ‘Qinmei’ and ‘Hayward’ kiwifruits, and the sensitive electrical parameter for all four samples was equivalent parallel inductance (Lp). Based on the relationship between VC content and Lp, described by a regression equation, CPPU treated kiwifruits could be non-destructively tested and distinguished from the untreated ones. There was no significant correlation between percentage mass loss and electrical characteristics, and it was impossible to establish a mathematical model to achieve non-destructive testing of kiwifruit freshness.

Key words: 1-(2-chloropyridin-4-yl)-3-phenylurea, mass loss, kiwifruit, quality, electrical properties