Influence of apple peel powder addition on the physico-chemical characteristics and nutritional quality of bread wheat cookies

Apple peel, a food industry by-product, is rich in fibre, polyphenols and minerals, and is a potentially attractive ingredient for bakery products. To evaluate the effect of wheat cookies enrichment with apple peel powder six types of cookies with increasing apple peel powder percentage (0%, 4%, 8%, 16%, 24% and 32%) were produced. The traits analysed were: pasting parameters; chemical properties (moisture, ash, lipid, protein, fibre and total polyphenols content); antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power methods); physical attributes (width, thickness, volume and CIE lab colour); and sensory characteristics (external appearance, internal structure, texture, odour, taste and aroma). Statistical analysis included analysis of variance followed by Fisher's least significant difference test (p < 0.05). The apple peel powder-enriched cookies had significantly higher moisture, ash, lipid, fibre, total polyphenols and antioxidant capacity than the control bread wheat cookies. The addition of apple peel powder did not modify the physical characteristics and improved the sensorial quality of the products. The addition of 24% apple peel powder gave the cookies with the best overall quality.