Date of Award
Master of Science
Food Science and Technology
M.P. Penfield, J.R. Mount, F.A. Draughon
Apple pomace consists of the solid material that remains after the juice has been extracted from apples for juice and cider production and the waste generated during the preparation of apples for canning, drying or freezing. Approximately 1.3 million tons of apple pomace are produced each year and the total annual disposal fee exceeds $10 million. Although there are alternatives to the disposal of pomace, relatively little progress has been made to minimize the cost of pomace disposal. In this study the physical and chemical characteristics of apple pomace obtained from 'Golden Delicious', 'Red Delicious' and 'Winesap' apples after the juice was extracted as unfiltered cider was measured, the effect of drum-drying on the pomace was determined and the acceptability of apple tart filling and oatmeal cookies prepared with apple pomace was evaluated. The severe heat treatment of the drum drying process caused significant loss, when compared to the milder vacuum oven drying, of all solids components except insoluble dietary fiber and carbohydrate. The level of all solids components of pomace except soluble dietary fiber was related to cultivar of the fruit. Drum-dried pomace was low in moisture, 1.38%; crude protein, 2.18%; ether extract, 1.08%; ash, 5.51% and soluble dietary fiber, 3.19% and high in insoluble dietary fiber, 33.56% and carbohydrate, 51.70%, on the dry weight basis (DWB). Drum-dried pomace had a pectin content of 11.85-20.20%. 'Winesap' pomace had the highest calculated caloric content at 217.81 Kcal per 100 g (DWB) and 'Red Delicious' pomace, the lowest at 184.71 Kcal per 100 g. The drum-dried pomace blend used in the apple tart filling and the oatmeal cookies had Hunter L, 'a' and 'b' color values of 51.48, 5.42 and 18.16, respectively. The water hydration capacity of drum-dried pomace was 3.36-3.96 mL per g, depending upon the cultivar. Because of the low aw, 0.12-0.15, and pH, 4.33 ± 0.03, of pomace, microbial counts, on drum-dried pomace of all cultivars stored over desiccant at ambient room temperature for 90 days were log 0.7-2.8 CPU per g pomace. The sensory panel did not indicate a difference in acceptability between the apple tart fillings or among oatmeal cookies prepared with pomace and scored the sensory characteristics of acceptability for the products as "like very much" to "like slightly." Pomace may be used successfully as a food ingredient in apple tart filling at levels of 10 and 20% of the total formula weight and oatmeal cookies at levels of 30, 40, and 50% of the amount of oatmeal in the cookie formula.
Carson, Kimberlee J., "Characteristics of apple pomace and its use in food systems. " Master's Thesis, University of Tennessee, 1990.