Non-destructive sensing methods for quality assessment of on-tree fruits: a review

Optimum maturity at harvest is a very important determinant to ensure the final quality of the fruits. Harvesting fruits at appropriate time maintains different quality parameters such as taste, size, shape, nutritional parameters and also have longer shelf life. While as fruits picked too early or too late in season are more susceptible towards different physiological disorders as well as have very shorter shelf life. So optimal harvesting time judgement is one of the most important information for various fruit growers to optimize the yield and to decrease the on-field losses. In recent years, various rapid and reliable non-destructive sensing techniques along with different multivariate, data fusion, and chemometric algorithms have been evolved to measure the quality parameters of different fruit samples at the time of harvesting. This paper presents an extensive review on different on-field issues during harvesting of various fruits and also how these issues significantly contributes to fruit spoilage all over the world. Presented paper also consist review on different non-destructive sensing techniques (electronic nose, spectroscopy, ultrasonic, imaging etc) along with various data processing algorithms (data treatment, feature extraction, data fusion etc) used for quality assessment of different fruit cultivars. Scope of multiple non-destructive sensing techniques fusion, challenges and bottlenecks also have been explored in the context of fruit quality assessment. Various products available in global market are also reviewed based on their sensing technique, application, prediction capabilities, cost, accessibility and reliability.