Fruit ripeness sensors based on poly(lactic acid)/polyaniline solution blow-spun fibrous membranes

Abstract

Real-time ripening monitoring stands as an attractive way to guarantee quality control and prediction of shelf life during transport and prolonged storage of fruits and vegetables. Herein, we investigate the use of poly(lactic acid)/polyaniline (PLA/PANI) solution blow-spun nanofibrous membranes as gas sensors for fruit ripening monitoring. PLA/PANI with different blend ratios was prepared by dissolving PANI in dichloroethane (DCE) for further mixing with PLA and spinning onto interdigitated microelectrode (IME). The ripening process of four different fruits (apple, orange, banana, and cashew peduncle), climacteric, and non-climacteric fruits, was assessed over 72 h by real-time monitoring changes in volatile organic compounds (VOCs) released during fruit ripening. Since adsorption of VOCs onto sensor surface causes changes in electrical response, which is directly related to the fruit ripening process, PANI addition was essential to monitor the ripening. However, higher concentrations (2% PANI in PLA) impair sensor conductivity and sensitivity because of the agglomeration of conductive polymer particles, which directly influences the sensitivity and the average fiber diameter. One of the main findings, here, was the clear distinction between different patterns of monitoring curves according to the category of the analyzed fruit (climacteric or non-climacteric).