DETECTING THE EXTERNAL DEFECTS OF POTATO TUBERS USING A VISIBLE LASER

Abstract

ABSTRACT

Potato (Solanum tuberosum, L.) is considered as a source of the national income in Egypt, since the potato crop is exported abroad because it's high quality specifications. The aim of this study is to: Find out the potential of using the optical properties as a nondestructive quality assessment for detecting surface defects of Spunta potato tubers using a low-power Helium-Neon laser. The obtained results were as following: The percentage of reflection intensity of sound tubers (7.48%) was the highest. While, the reflection percentage of superficial shatter bruise (0.83%) was the lowest. The reflection intensity percentages of He-Ne laser light from sound and defective tubers were arranged as follow: Sound (7.48%) >, Internal black spot (4.33%) >, Greening (2.53%) >, Cuts (1.83%) >, Growth cracks (1.64%) >, Shrinkage (1.54%) >, Deep shatter bruise (1.33%) >, Rots (1.32%) >, Pressure bruise (1.09%) >, Skinning (1.07%) >, Insect damage (0.87%) >, Superficial shatter bruise (0.83%). For quality evaluation processes it was concluded that: when the percentage of reflection intensity is less than 1%, (Ref.%< 1%) then the defects may be considered superficial shatter bruise or insect damage, otherwise, when the percentage of reflection intensity greater than or equal 1% and less than 2%, (1% ≤ Ref.%< 2 %) then the defects may be considered skinning, pressure bruise, rots, deep shatter bruise, shrinkage, growth cracks or cuts, if the percentage is ranged between (2.5:4.5%) then the defects may be belonging to greening defect or internal black spot. The percentage of reflection greater than 7% the surface may be considered as sound tubers. It was concluded that the reflected laser light could be used as an indicator for the defective surface defects of potato tubers, so sorting and separating processes can be conducted according to the optical properties.