Sorting and grading is done to separate the good harvest and the ugly as well as separating or classifying products into quality class / grade according to criteria of quality class / grade of each commodity / product. Factors of quality or quality criteria can be grouped into 3 groups including the physical properties, chemical properties and biological zero. The physical properties include moisture content, size, shape, weight, density, texture, color, density, foreign bodies and others.
Chemical properties include chemical components, rancidity, free fatty acids indices, smell, taste, and other residues, while the biological properties include germination, sprouting, the type and amount of damage by microbes. Penggelompokkan quality factors can be seen in the diagram below.
Figure 4. Grouping of quality factors based on the nature of physics, chemistry and biology
Fruits, vegetables and flowers are a group of non-homogenous products. They vary a) among the group, b) among individuals in the group and c) inter-regional production. Differences arise because of differences in environmental conditions, cultivation practices and different varieties. As a result, any grading operation should handle variations in the total volume of the product, the size of individual products, product conditions (maturity and level of mechanical damage) and “frailty” of the product.
Several other factors also affect the quality of the product is done before grading, include: Stadia ripeness when harvesting; a method for transferring products from the field to the grading; method of harvest and the time taken between harvesting and grading. Grading provide benefits for the whole industry, from farmers, wholesalers and retailers because of its size uniform for sale. Maturity uniform will avoid pieces of broken and abrasions, better profits because of the uniformity of the product as well as reduce costs for transport and marketing due to faulty materials in reserve.