Different Types of Shelf Material for Kitchen Cabinets
Despite their simplicity, shelves are a key component in your cabinets because they support the major part of the weight within the cabinet. Thickness and material choices are the most important factors because they determine both the rigidity and strength of the shelves. Plywood and solid wood are the best choices for shelf material as they provide better rigidity than MDF or particle board for a given thickness and shelf span. Of course, the thicker the shelf, the more firm it will be. In the picture to the right, the arrow is pointing to the ‘shelf material’.
Plywood for shelf material 
Plywood is considered the premium option for shelf material. The strong material and solid-core employs several layers of wood plies or veneers at varying angles for stability and stiffness. Many cabinet makers offer plywood as an upgrade for top-of-the-line cabinet box material but here, it's standard. We want our cabinets to be as strong and as durable as possible.
MDF for shelf material 
MDF is an engineered wood product made from wood fibers that are pressed and bonded together. Like particle board, it's susceptible to water damage and is very heavy, adding to the overall weight that's suspended from the hanging rails on the back of the cabinet. MDF is much lower in quality and is much cheaper than plywood. It is definitely not the best choice for cabinets, although it is better than particle board. You will see this used in many mid-level cabinet brands.
Particle board for shelf material 
Particle board is widely used to make shelf material and other components. It is an engineered wood product manufactured from wood particles, such as wood chips, sawmill shavings or even saw dust and held together by a synthetic resin or other suitable binder, which is pressed and extruded. It's then covered with a melamine, wood veneer or vinyl laminate layer.
Particle board has many drawbacks. It's susceptible to damage from liquids, doesn't hold screws as well as plywood, and is much weaker and susceptible to bending and warping. Some particle board also gives off formaldehyde vapors based on the constituents of the adhesives used to bond the wood particles.