The melding of cultures contributed significantly to the melding of foods and food preparation in Mexico, often referred to as mestizaje, or mixing. Corn, a staple for over 4,000 years, is the backbone of the diet. The kernels are softened in water and lime and then ground and fashioned (most commonly) into tortillas. Protein-rich beans and an infinite variety of chilies round out this holy trinity of Mexican cookery. The Spanish liked what they saw in Mexico and added a few things of their own, among them domestic animals, sugar and cheese. Mexican cuisine is further enhanced by an incredible array of fruits.