Assessment of avocado textural changes during ripening by using contactless air-coupled ultrasound

[EN] In the present study, the use of the air-coupled ultrasonic technique has been analysed as a new tool for the contactless assessment of the avocado post-harvest textural modifications during ripening. Thus, ultrasonic parameters, such as maximum wave amplitude and ultrasound velocity, and textural ones, such as hardness, elastic modulus and relaxation capacity, were measured on avocado slices. During ripening, avocado reduced its elastic modulus (from 2.29 +/- 0.75 to 0.16 +/- 0.08 MPa), became softer and became more viscoelastic, which was well described from zero and first-order kinetic models. These changes increased ultrasound attenuation, decreasing the maximum amplitude of the ultrasonic signal (from 336.6 to 55.4 V/m), while the ultrasonic velocity remained constant, between 320.1 +/- 6.9 and 316.4 +/- 82.6 m/s. Thereby, the maximum ultrasonic amplitude, which adequately correlated with textural parameters (r(avg) = 0.85), could be used to assess the post-harvest ripening on avocado slices.The authors acknowledge the financial support from the Ministerio de Economia y Competitividad (MINECO) and Agencia Estatal de InvestigaciOn in Spain (Project RTC-2017-6314-2) and the Generalitat Valenciana. M.D. Farifias is grateful to the European Social Fund (ESF 2014-2020) and Generalitat Valenciana for her post-doctoral fellowship (APOSTD/2018/203). The author E.A. Sanchez-Torres acknowledges the support of the undergraduate student Sara Serrano Garcia on the experimental work.Fernandez-Caballero-Fariñas, MD.; Sanchez-Torres, EA.; Sanchez-Jimenez, V.; Díaz, R.; Benedito Fort, JJ.; Garcia-Perez, J. (2021). Assessment of avocado textural changes during ripening by using contactless air-coupled ultrasound. Journal of Food Engineering. 289:1-9. https://doi.org/10.1016/j.jfoodeng.2020.1102661928