The Influence of Hazelnut Skin Addition on Quality Properties and Antioxidant Activity of Functional Yogurt

Abstract

There is an increasing interest in applying fruit-processing wastes as functional food ingredients. Hazelnut skin, an interesting and innovative ingredient has recently been evaluated as one of the richest edible sources of polyphenolic compounds. This study aimed to evaluate the use of hazelnut skin as a functional additive in yogurt and to determine the effect of various percentages (2%, 3%, and 4%) of hazelnut skin on the physicochemical, microbiological, rheological, biochemical, and sensorial properties of yogurt. The results showed that the addition of hazelnut skin significantly increased total solids from 16.5% to 17.7% and fat content from 3.45% to 4.60% and decreased titratable acidity by up to 36%. The enrichment with hazelnut skin also improved the viability of yogurt bacteria, water holding capacity (WHC), and antioxidant activity of yogurts. Better results for WHC and antioxidant values were found in yogurt enriched with 4% hazelnut skin. Total phenolic content and Fe2+ chelating activity of yogurts increased with the increasing hazelnut skin ratio. However, yogurts with hazelnut skin had low instrumental texture parameters and apparent viscosity values. On the other hand, acceptable sensorial properties similar to control yogurts increase the consumption potential of yogurts enriched with hazelnut skin.

Optimization of Conventional Extraction Parameters for Recovering Phenolic Compounds from Potato (Solanum tuberosum L.) Peels and Their Application as an Antioxidant in Yogurt Formulation

“…Likewise, Ahmed et al [ 13 ] noticed that the DPPH • radical scavenging activity was higher by 108.6% in yogurt containing 0.2% argel leaf extract compared to the control. The enrichment with hazelnut skin also enhanced the TPC and antioxidant capacity of yogurts [ 19 ]. The supplementation of yogurt with cryo-concentrated strawberry pulp resulted in a product with 3-fold more anthocyanins and antioxidant capacity [ 21 ].…”

“…The fluctuation in the antioxidant capacity of yogurts enriched with various plant matrices may be due to numerous factors such as their origin and composition. Furthermore, milk protein proteolysis and organic acid formation derived from microbial metabolic action during fermentation and cold storage may have contributed to the increased antioxidant capacity [ 19 ].…”

“…Purple sweet potato used to fortify yogurt has improved its functional values [ 17 ], and adding 15% pumpkin pulps enhanced some chemical, physicochemical, and sensory characteristics, as well as the antioxidant capacity of stirred yogurt [ 18 ]. Similarly, yogurt enriched with hazelnut skin showed enhanced bacteria viability, water holding capacity, and antioxidant capacity [ 19 ].…”

Lactate content, total polyphenols and antioxidant activity of selected commercial yogurts from the Serbian market

“…Literature data shows the common use of these tests alone or in combination for the assessment of the antioxidant activity of various plants (Nowicka et al, 2019;Dinkçi, Aktaş, Akdeniz & Sirbu, 2021;Pavlović et al, 2021; O N L I N E F I R S T Batinić et al, 2022). Results for antioxidative activity determined by the DPPH test and reducing power for methanolic and ethanolic extracts are presented in Table 2.…”

Lactate content, total polyphenols and antioxidant activity of selected commercial yogurts from the Serbian market

“…Literature data shows the common use of these tests alone or in combination for the assessment of the antioxidant activity of various plants (Nowicka et al, 2019;Dinkçi, Aktaş, Akdeniz & Sirbu, 2021;Pavlović et al, 2021;Batinić et al, 2022). Results for antioxidative activity determined by the DPPH test and reducing power for methanolic and ethanolic extracts are presented in Table 2.…”