Chemical Composition of Enzymatically Digested Food Waste Byproducts

Fruit, vegetable, meat, and dairy food waste was collected from supermarkets and processed using enzymatic digestion, pasteurization, and stabilization. The screened and separated final byproduct was 90% liquid food waste (LFW) and 10% solid food waste (SFW). Chemical composition of the LFW and SFW was determined as a first step for their use in diets of pigs. Thus, 11 batches of each of LFW and SFW were collected and analyzed for dry matter (DM), crude protein (CP), amino acids (AA), ash, ether extract (EE), crude fiber (CF), acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), fructose, glucose, sucrose, maltose, stachyose, verbascose, starch, macro-minerals, micro-minerals, and fatty acids. On a DM basis, LFW contained 22.05% DM, 22.05% CP, 36.58% EE, 0.48% Ca, 0.33% P, 7.50% glucose, 5.14% fructose, 3.38% ADF, 5.81% NDF, and 65.48% unsaturated fatty acids. SFW contained 28.98% DM, 19.53% CP, 34.43% EE, 2.69% Ca, 1.12% P, 5.61% glucose, 3.71% fructose, 17.27% ADF, 25.51% NDF, 63.63% unsaturated fatty acids on a DM basis. Concentrations of these components in LFW were compared with those in SFW using t-test in SAS. Results indicated that DM, ash, CF, Ca, P, Mg, S, Cu, Zn, Mn, starch, ADF, NDF, ADL, hemicellulose and cellulose were greater (P < 0.05) in SFW than in LFW. Concentrations of all indispensable AA and all dispensable AA except for glycine were greater (P < 0.05) in LFW than in SFW. While both LFW and SFW contain enriched nutrients for non-ruminant animals, the high concentration of fiber components in SFW will limit the use of this byproduct in nursery pigs. However, the combination of LFW and SFW will dilute the fiber content, and thereby balance nutrients for both nursery and growing pigs. The relatively high concentration of fat will probably limit the inclusion rate of both byproducts in late-finishing pig diets. Further research will be conducted to evaluate the growth performance of nursery and growing-finishing pigs by feeding the combination of LFW and SFW.