Blackspot bruise in potatoes: susceptibility and biospeckle activity response analysis

Abstract

Blackspot bruise in potatoes can lead to enormous economic losses and pose threat to human diet, making an undesired damage that can be easily ignored due to its invisibility to human naked eyes. Susceptibility analysis addressing potato part (i.e. body, stem-end and bud-end) and volume (i.e. small, medium and big) was first carried out. Biospeckle imaging technique, possessing the merits of low-cost, fast, non-destructive and qualitative/quantitative processing, was then investigated for extraction of biospeckle activity (BA). BA responses to blackspot bruise in potatoes were evaluated afterwards. Two modified BA extraction methods (i.e. CCSP_WE and CCSP_MWE) were proposed for comparison with original method THSP_WE. Potato volume and bruised part were analyzed to study their influences on BA responses using the three methods. CCSP_WE method was superior to CCSP_MWE and THSP_WE for its better robustness and discrimination ability. Afterwards, all samples were divided into two sets (i.e. control and test), where the test set consisted of normal and blackspot bruised samples. It was found that BA of blackspot bruise was bigger than that of control samples, but it behaved similarly when compared with normal samples. Therefore, it was concluded that BAs derived from the three methods in this study are not sensitive to blackspot bruise in potatoes. Unsatisfactory results of this study are expected to serve as a contrast in improvement of related discipline.