Influence of the addition of different hazelnut skins on the physicochemical, antioxidant, polyphenol and sensory properties of yogurt.

Skins obtained from three different varieties (Georgia, San Giovanni and Tonda Gentile Trilobata) of roasted hazelnuts (Corylus avellana L.) were used at two different percentages (3% and 6%) in yogurt production to increase the dietary fibre and polyphenol content. The effects on the physico-chemical characteristics, antioxidant capacity, phenolic compounds, and sugar and organic acid content during 3 weeks of storage at 4 °C were evaluated, and a preference test was performed with consumers at the end of storage. The amount of skin and the variety used significantly influenced all of the physico-chemical parameters and were associated with consumer preference. Concerning the dietary fibre content, total polyphenol content and antioxidant capacity, all of which affect the functional ability of food products, the highest values obtained were for all of the products contained a hazelnut skin content of 6%. Among the cultivars, the highest values obtained were for yogurt with the Georgia hazelnut skin. Although 6% hazelnut skin yogurts displayed the highest functional ability, a decreased consumer preference was observed; yogurt with 3% San Giovanni and Tonda Gentile Trilobata hazelnut skins had the maximum consumer rating.