  Automated technologies for quality inspection of fruits have attracted great
interest in the food industry. The development of nondestructive mechanisms to
assess the quality of individual fruit prior to sale may lead to an increase in
overall product quality, value, and consequently, producer competitiveness.
However, the existing methods have limitations. Herein, a texture sensor based
on highly sensitive hair-like cilia receptors, to allow a quick quality
evaluation of fruit is proposed. The texture sensor consists of up to 100
magnetized nanocomposite cilia attached to a chip with magnetoresistive sensors
in a full Wheatstone bridge architecture. In this paper we demonstrate the use
of ciliary sensors in scanning fruits (blueberries and strawberries) in
different maturation stages. The contact of the cilia with the fruit skin
provided qualitative information about its texture in terms of ripeness stage.
Less mature fruits exhibited, on average, a highest peak voltage of 0.14 mV for
blueberries and 0.12 mV for strawberries, while overripe fruits exhibited 0.58
mV and 0.56 mV, respectively. The results were confirmed by sensorial
assessment of the fruit freshness, and therefore attesting the application
potential of the sensing technology for fruit quality control.
