Effect of Walnut (Juglans regia L.) on the Physicochemical, Sensory, Phenolic and Antioxidant Properties of Set Type Yogurts during Storage Time

Abstract

This study aims to reveal the quality properties of yogurt enriched with walnut during cold storage (4°C) for 28 days. Five sets of yogurt types were produced by using walnut at varying rates (A: 0% (control), B: 1%, C: 2.5%, D: 3.5%, E: 5%). Physicochemical, sensory, phenolic contents and antioxidant properties of yogurt samples was investigated during the 1st, 7th, 14th, and 28th days of storage. The study was conducted to optimize the walnut addition level to obtain better quality yogurt as a functional food. It was determined that the walnut enrichment affects the gross chemical component of yogurt samples. Yogurt sample with %5 walnuts (E) had the highest total phenolic and antioxidant activity content (respectively 1027.50 mg GAE/kg, 19.95 mM TE) among the samples. The yogurt sample with the highest sensory attribute score was the one containing 1% walnuts. Therefore, it was concluded that yogurt added with walnut could serve as functional yogurt beneficial for human health.