Scattering through fruits during ripening: laser speckle technique correlated to biochemical and fluorescence measurements

Abstract

This paper reports monitoring fruits maturation using speckle technique. Performed measurements aim the assessing of biological inner fruit variation effect on the speckle image. We show that the speckle grain size is both affected by the glucose level inside the fruits and by the chlorophyll content. Moreover, the determination of circular polarization degree and circular grain size indicate that a Rayleigh diffusion regime gradually becomes predominant in fruits. Principal component analysis is used to highlight high correlation between results and strengthen the establishment of speckle as a novel non invasive method to monitor fruits ripening.

Detection of Golden apples’ climacteric peak by laser biospeckle measurements

“…Many studies reported in the literature show the efficiency of the biospeckle technique in monitoring ripening of fruits [5] like oranges [6], tomatoes [7], apples [8][9][10], and pears [11], during shelf life [8], and in assessing quality parameters in fruits, such as pathogen detection in wheat seeds and coffee beans [12]. Speckle activity is generated by a biological medium illuminated by coherent light.…”

“…Speckle activity is generated by a biological medium illuminated by coherent light. When light is scattered off samples, the objective speckle patterns are recorded and analyzed, thus determining the fruits' underlying intrinsic activity [11].…”

Le speckle pour mesurer la maturité des fruits climactériques

“…L'utilisation du champ de speckle dans le suivi de la maturation des fruits permet d'explorer les paramètres de diffusion dans le fruit et d'accéder à leurs changements au cours de la maturation en s'appuyant sur des variables statiques ou dynamiques du speckle [5,6,7]. Le développement d'un prototype expérimental portable, compact et fibré permettrait à des professionnels non spécialistes de l'optique tels les ingénieurs agronomes et agroalimentaires, d'effectuer un suivi instantané et in situ de la maturation des fruits et de leur évolution physiologique interne.…”

Determination of macaw fruit harvest period by biospeckle laser technique

“…Chlorophyll levels tend to decrease during maturation, decreasing the absorption of laser light and consequently increasing the scattering intensity and the values of biological activity. Nassif et al (2012) and Hu et al (2013) demonstrate a significant correlation between chlorophyll and biological activity for various fruits. In the case of macaw palm, more in-depth studies are necessary with the objective of obtaining a relation between the biological activity and physiological factors during a maturation.…”