Selection of food waste with low moisture and high protein content from Mexican restaurants as a supplement to swine feed

Abstract

Food waste (FW) handling is a complex problem. Discarding food with nutritional value attempts against food safety and amounts to wasting the natural resources needed in its production. Developing concrete alternatives to valorize FW is becoming increasingly important. The transformation of FW from restaurants into swine feed is evaluated in this work. The FW is collected from restaurants and classified according to its composition as citric (CiW), vegetable (VeW), cereal (CeW), and processed food waste (PFW). An optimization strategy is performed to select the combination of FW with minimum moisture content that not only meets the nutrient requirement of pigs in their last breeding stage but also reduces the energy-related costs involved in the drying stage. The collected FW comprises 28.42, 25.37, 7.47, and 38.74 percent, of CiW, VeW, CeW, and PFW. According to their bromatological characterization, the first three wastes are rich in carbohydrates (68.87–73.74% on dry basis), whereas PFW is more balanced (average protein and fat contents are 17.91 and 24.85% on dry basis). The FW mix with the least moisture content consists mainly of PFW and CeW, with 59.77 and 37.65%. Maize must be added to the mixture to satisfy the ideal amino acid content. The proposed swine feed from FW contributes to reducing the need for costly meals with high protein content, such as soy meal.