Evaluation on Feed-Nutritional Change of Food Waste According to Different Processing Methods and Trouble-shooting Strategy

Abstract

This study was conducted to introduce recycling procedures of food waste (FW) as feed according to the dehydration, semi-dehydration fermentation and liquid fermentation methods through the on-site survey of companies related, to trace physico-chemical components and nutritional losses depending upon the processing stage for each method and finally to suggest more desirable methodology for the efficient utilization of FW as animal feed. For the dehydration method, dewatering of FW alone reduced (P<0.05) moisture (approximately 10%) and ether extract contents and increased (P<0.05) fiber contents. Dewatering and subsequent dehydration of FW decreased (P<0.05) contents of ether extract, limiting amino acids such as lysine, methionine and histidine, pepsin digestibility of protein by half, and NaCl content by 40%, increased (P<0.05) contents of fiber, crude ash, Ca and P, and did not alter (P>0.05) pH. The semi-dehydration fermentation method of FW did not affect (P>0.05) the chemical components, pepsin digestibility of protein, pH and NaCl content. For the liquid fermentation method, pasteurization and fermentation of FW decreased (P<0.05) contents of dry matter, ether extract, crude fiber, lysine and NaCl; however, it did not affect (P>0.05) other chemical components, pepsin digestibility of protein and pH. Among the processing methods, nutrient losses were highest for the dehydration method (25% of metabolizable energy loss, 12% of organic matter loss) and little for the semi-dehydration and liquid fermentation methods. The on-site survey of companies related revealed that the existence of foreign materials in FW products were problematic for all the three companies surveyed, thus it was necessary to develop a more efficient screener. Before feeding FW-containing diets to pigs, high quality of protein and energy feedstuffs needed to be fortified for the dehydration method. For the semi-dehydration fermentation method, the scientific diet formulation technology was required at the initial mixing stage. For the liquid fermentation method, possibly most energetic and proteinaceous feeds needed to be supplemented for the normal animal growth.