Smart fingertip sensor for food quality control: Fruit maturity assessment with a magnetic device

Abstract

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.

A tactile and airflow motion sensor based on flexible double-layer magnetic cilia

“…With the rapid development of magnetic sensors, it is possible to detect small changes in a magnetic field during the bending of magnetic cilia 15,16 . To produce magnetic cilia, some studies have used the demolding method [17][18][19][20][21][22][23][24][25] . A hard mold is perforated first by laser processing or etching with photolithography.…”

Recent Progress of Biomimetic Tactile Sensing Technology Based on Magnetic Sensors

“…This is the lowest known texture height that can be detected with a tactile sensor. Benefiting from its powerful ability, this sensor was also used to distinguish the rotten state of fruits [ 71 , 122 ], as shown in the left of Figure 16 a. When cilia crossed the surface of different fruits, the rotten state of fruits could be recognized according to the different signal of the sensor.…”

Microfluidic Applications of Artificial Cilia: Recent Progress, Demonstration, and Future Perspectives

“…The second section is the signal processing section. Graphene nanoplatelets [ 41 ], carbon nanotubes (CNTs), SiO 2 , carbon nanofiber, iron nanowires, and AgNW were employed as the sensing/signal processing part [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. Signals such as the piezoelectric and piezoresistive types were created due to cilia bending and processed through the signal processing units [ 41 ].…”

“…In addition, this method is highly controlled together with high throughput, compared to the bead self-assembly [ 59 , 60 ], which required additional control [ 58 ]. The recent discussions and approaches over photolithography processes to fabricate artificial cilia can be found elsewhere [ 29 , 44 , 61 , 62 ]. Figure 1 B illustrates the photolithography fabrication process depicted fabricating magnetic artificial cilia following processes such as: (i) substrate preparing, (ii) anchor preparing, (iii) cilia body layer preparing, (iv) ciliary shape developing, (v) cilia coating, and (vi) peeling-off.…”

“…Nanotubular cilia with polyimide substrate on the nonpatterned Anode Aluminum Oxide (AAO) templates and Cr and Au deposition by sputtering created a non-harmful flexible temperature sensor which was successfully tested on the eggshell without electrical failure ( Figure 5 C) [ 160 ]. Another study [ 44 ] was recently established where the magnetized nanocomposite artificial cilia were embedded with working magnetoresistive sensors. The fabricated sensors sensed the mature level of the strawberries and blueberries nondestructively.…”