Abstract of Masters Thesis

Transformation of the Food Processing Waste Apple Pomace into a Value Added Product

A. Leary, Institute of Technology, Tralee (2009)

Increasing environmental pressures for greener industrial practices, coupled with increasing consumer awareness for functional food products, is driving a demand for naturally derived and nutritionally valuable food ingredients. Pectin and dietary fibre are found in high quantities in apple pomace waste of the cider industry. This research aims to upgrade apple pomace to a functional food ingredient, providing a lucrative alternative use to animal feed. Apple pomace (pH 2.5; 25.02% Total Solids) was subjected to chemical (acid or alkali) and enzymatic pre-treatments. Enzymatic pre-treatments included cellulases, hemicellulases, β-galacturonases and pectinases. Oven drying trials resulted in impenetrable solid masses while freeze drying generated an apple pomace flour which is easily utilized and stored with a total solids of 89.58% (chemical treatment) and 75.81-93.37% total solids (enzymatic treatments). These freeze dried flours were tested to compare the chemical versus enzymatic effects on pectin content, dietary fibre content, water binding capacity (WBC) and viscosity. Water binding capacity (WBC) is an important functional requirement in many foods. Preliminary WBC results on apple pommace extracts ranged from 9.7345-15.4795g ±0.9g and 5.7597-15.0891g ± 0.7g H2O bound/g of apple pomace flour for cold and hot chemical treated samples respectively. For enzyme treated apple pommace, WBCs of 1.7295-13.1040g ±1.0g and 2.5414-18.3702g ±1.0g were obtained for cold and hot treatments respectively. These treatments show a significant increase in WBC to untreated apple pommace which yielded a WBC of 2.9415g ±0.3g. Although apple pomace can be upgraded to functional food ingredients, the chemical and enzymatic processing of this material is sensitive to conditions including pH, temperature and salts.