Monitoring the effect of cutting blade sharpness on quality of fresh-cut product

Mechanical damage during processing operations such as peeling and cutting is one of the major factors affecting the quality and shelf life of the fresh cut produce. The intensity of mechanical damage is highly associated to the morphology of the cut tissue and to the sharpness of the cutting tool used. The degree of sharpness (DoS, defined as the required force exerted by the instrument to cut a reference body) is an important factor for an efficient cutting operation and a methodology has been developed in order to formulate an objective assessment method to be applied to evaluate cutting damage on fresh-cut products. To this aim, 3 kitchen knives (A, B and C) were used with 8 DoS values (from 1, sharpest to 8, bluntest) to cut silicon plugs as reference bodies with cross-section diameters of 6 and 8-mm. For the 6-mm plugs and knife A the force varied from 16.2 +/- 0.5 N (DoS=1) to 93.6 +/- 7.0 N (DoS=8), for knife B from 17.9 +/- 0.4 (DoS=1) to 80.1 +/- 6.1 N (DoS=8), and for knife C from 17.4 +/- 0.9 (DoS=1) to 155.3 +/- 2.0 N (DoS=8). As for the 8-mm plugs forces ranged for knife A, B and C from 26.0 +/- 1.1 N (DoS=1) to 105.6 +/- 7.6 N (DoS=8), from 29.0 +/- 1.3 (DoS=1) to 104.6 +/- 6.5 N (DoS=8) and from 26.1 +/- 0.7 (DoS=1) to 195.9 +/- 11.7 N (DoS=8) respectively. Cutting force mean values for all knives and DoS resulted statistically significant in relation to standard deviation values. Following, kitchen knives at 3 different DoS corresponding to 30, 90, and 140 N of cutting forces, labeled as DoS1, DoS2 and DoS3 respectively, were used to cut fresh apples and quality of the product was evaluated during storage in terms of changes in the visual appearance (sensorial), CIELAB values and chemical response. It was confirmed that color changes in terms of browning were higher as the DoS decreased with data significantly fitting an exponential relation. These and the other results indicate a potential for further research aimed to define the threshold in terms of sharpness of cutting tools after which the effects on quality of the product would be not compatible with its commercial value.