Time–temperature tolerance of harvested green bananas exposed to high temperatures

• Published in: Scientia horticulturae 2024-04, Vol.329, p.112970, Article 112970
• Main Authors: Sugianti, Cicih, Imaizumi, Teppei, Thammawong, Manasikan, Tsuta, Mizuki, Nagata, Masayasu, Nakano, Kohei
• Format: Article
• Language: English
• Subjects: Banana; bananas; color; equations; ethylene; exposure duration; firmness; High temperatures; oxalic acid; prediction; relative risk; sugar content; temperature; Time–temperature tolerance
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/j.scienta.2024.112970

•Comparative tests revealed the time-temperature tolerance of green bananas.•High-temperature exposure affected banana quality after ripening.•The risk ratio was newly introduced to assess the probability of abnormal ripening.•The critical duration for which bananas can remain in an orchard was predicted. In this study, the time–temperature tolerance theory was adopted to determine the critical duration for postharvest banana exposure in the plantation without the emergence of physiological disorders and quality loss. Bananas were exposed to various high temperatures (35 °C–51 °C) for durations ranging from 5 min to 12 h. Subsequently, they were treated with 200 ppm ethylene for 24 h and stored at 20 °C for ripening. The ripening color index was monitored during storage, and when it reached 125, quality attributes in treatments were compared, including L* value, sugar content, oxalic acid content, firmness, and pulp-to-peel ratio. Bananas exposed to temperatures ≤40 °C ripened normally, whereas those exposed to temperatures of ≥45 °C exhibited reduced sugar content depending on exposure duration. A linear fractional model effectively expressed the relationship between the flesh temperature and the critical time limit for normal ripening. Introducing a new indicator, the risk ratio (RR), allowed the assessment of abnormal ripening probability, which was assumed to vary according to zero-order kinetics. The temperature-dependent rate constant of RR adhered strongly to the Arrhenius equation, enabling RR prediction under specific temperature conditions. In validation testing, bananas with an RR of 0.9 exhibited sugar content equivalent to the control, whereas those with an RR of 1.1 showed significantly lower sugar content. Overall, this study demonstrates a novel approach for estimating the critical safe duration bananas can remain in the field after harvest, thereby mitigating postharvest losses.