The production of hazelnuts in 2012 was 914.447 *109 kg. Turkey
was the world's largest producer and contributed 72% of the total
production, followed by Italy (9.3%), the United States (3.3%) and
Georgia (2.7%) (FAOSTAT, 2012). Two different by-products are
obtained during the transformation of hazelnuts through the post
absorption, whereas IDF has a high water-holding capacity that
contributes to increased faecal bulk. Currently, an average daily
fibre intake of 25 g for adults and 10 g (1e3 years old) to 21 g (17
years old) for children is recommended.
Antioxidants are notably important compounds in food science
due to their ability to prevent lipid oxidation in foods and to
decrease the negative effects of reactive oxygen species on physiological functions in humans. Polyphenols, which are widely
distributed in plants, are among the most studied natural antioxidants due to consumer preference for natural products.
Currently, a daily polyphenol intake of 1 g is reported (Scalbert,
Manach, Morand, Rem esy, & Jimenez, 2005 ). Recently, hazelnut
skin itself or its phenolic extracts have been added to vanilla ice
cream, bread or coffee to investigate the effects on the final
products in terms of fat replacement, as a source of dietary fibre
and as a potential source of antioxidants, respectively. The application of hazelnut skin to ice cream demonstrated that it could
improve product overrunning, but it resulted in greater susceptibility to melting and was not preferred by consumers (Dervisoglu,
2006). The use of hazelnut skin in bread revealed that a concentration of 5% did not considerably affect the rheological properties
of the dough or the final product and produced acceptable results
from the sensory panel (Anil, 2007). Contini, Baccelloni,
Frangipane, Merendino, and Massantini (2012) emphasized that
phenolic extracts from hazelnut skins increased the antiradical
activity of coffee due to an increase in the total polyphenol
content.
Therefore, the aim of this work was to evaluate the possibility of
using hazelnut skin as a source of dietary fibre and antioxidants in
yogurt. The use of hazelnut skin in yogurt could have a dual benefit
by employing a food industrial by-product for human nutrition,
thereby reducing industrial waste. In addition, it could augment the
consumption of fibre and antioxidant compounds in all sectors of
the population owing to the popularity of yogurt around the world
(61.248 *109 kg yogurt production e FAOSTAT, 2012).