Non-Invasive Sweetness Classification for Citrus Maxima

Ripe “Citrus maxima,” also known as pomelo, is mostly the same based on their appearance and skin color. For this instance, the classification of pomelo sweetness is quite tricky. According to a study, ripe fruit produces ethylene (C2H4) gas associated with fruit ripening level. The odor comes from molecules in the air that stimulate receptors in the nose. The senses of smell and taste are directly related because they use the same type of receptors. Since the senses of smell and taste are related to each other, the researcher used the pomelo's smell or gas for the classification of sweetness. In this case, the researchers create an automated system that will classify the pomelo sweetness in a non-invasive procedure through E-nose. The study's objective is to help pomelo industries in classifying the sweetness of their product before selling it to the consumers. Also, it aims to develop a device to help satisfy the purchase of consumers of sweet pomelo. Since ethylene sensor is quite expensive, MQ3, MQ6, and MQ8 gas sensors are used to detect the gas emission produced by pomelo. The three MQ sensors are connected to the Arduino Uno microcontroller to analog reading in parts per million (ppm). For data gathering, data mining is used for data clustering and classification. The accuracy of the system is verified in an invasive procedure, specifically testing its “total sugar content.” The pomelos were first subjected to data gathering in the manufactured device. These pomelos were then extracted for their pure natural juice and sent to a laboratory testing to get its total sugar content percentage. Laboratory results of pomelo juices in total sugar percentage have been analyzed to verify the effectiveness of the non-invasive procedure in classifying the sweetness of citrus maxima. The laboratory and non-invasive results verified that the total sugar content could be identified correctly by the e-nose. Thus, MQ3, MQ6, and MQ8 gas sensors are capable of detecting pomelo gas emission as the basis of its sweetness classification.