Quality detection of watermelons and muskmelons using innovative nondestructive techniques: A comprehensive review of novel trends and applications

Watermelons and muskmelons are popular fruits among consumers worldwide which are sweet and have excellent nutritional composition. The quality detection of watermelon and muskmelon is an important factor in consumer preference, postharvest handling, and the commercial value of the fruit. Quality detection of watermelon and muskmelon has always been a challenging and essential task due to the uniqueness of their fruits and different application scenarios. Advances in optic and acoustic vibration techniques posted for their application in external and internal quality of watermelons and muskmelons, including machine vision, visible/near-infrared spectroscopy, hyperspectral imaging, and acoustic or vibration measurements. In this review, optic and acoustic vibration application in quality detection of watermelons and muskmelons with special emphasis on system composition, online equipment, merits, and limitations are presented. Moreover, the effectiveness of using multi-sensor information fusion technology for simultaneous detection of multiple quality is discussed. Furthermore, current challenges and future trends in this field are addressed. In particular, the multi-sensor-based commercial detection online equipment and smartphone-based mobile application will be the most useful tool for suppliers and consumers to assess the quality of watermelons and muskmelons.