Grader: A review of different methods of grading for fruits and vegetables

Abstract

Grading of agricultural produce especially the fruits and vegetables has become a perquisite of trading across borders.  In India mostly fruit growers grade the fruit manually.  Manual grading was carried out by trained operators who considered a number of grading factors and fruit were separated according to their physical quality.  Manually grading was costly and grading operation was affected due to shortage of labor in peak seasons.  Human operations may be inconsistent, less efficient and time consuming.  New trends in marketing as specified by World Trade Organization (WTO) demand high quality graded products.  Farmers are looking forward to having an appropriate agricultural produce-grading machine in order to alleviate the labor shortage, save time and improve graded product’s quality.  Grading of fruits is a very important operation as it fetches high price to the grower and improves packaging, handling and brings an overall improvement in marketing system.  The fruits are generally graded on basis of size and graded fruits are more welcome in export market.  Grading could reduce handling losses during transportation.

Grading based on size consists of divergent roller type principle having inclination, expanding pitch type, inclined vibrating plate and counter rotating roller having inclination type graders.  Weight grading based on density and specific gravity of agricultural commodities.  The need to be responsive to market demand places a greater emphasis on quality assessment, resulting in the greater need for improved and more accurate grading and sorting practices.  Size variation in vegetables like potatoes, onions provided a base for grading them in different categories.  Every vegetable producing country had made their own standards of different grades keeping in view the market requirements.

Keywords: grading, handling, packaging, color sensor, specific gravity, India