Antioxidant Activity of Greek-style Yogurt with Stevia Leaf Extracts

Abstract

This study was carried out to evaluate the antioxidant activity and total polyphnol content of Greek-style yogurt in 12% solid content with added stevia leaf extracts. Stevia leaf extracts used as sweetener in preparing Greek-style yogurt were prepared in hot water (100℃ for 6 h 3 times, and by 70% fermented ethanol for 24 h at room temperature 3 times). The antioxidant activities were measured by assessing the radical scavenging effect through DPPH, ABTS, and FRAP assays. To identify the compounds present, total polyphenol content was evaluated using a Folin-Dennis assay. The capability to scavenge free radicals and total polyphenolic content were the highest in Greek-style yogurt containing 1% stevia extract and fermented in 70% ethanol. According to the results, antioxidant activities significantly increased when high concentration of stevia extracts were added to the yogurt (p<0.05). Therefore, these results suggest that stevia leaf extracts can be used as a source of functional compounds in Greek-style yogurt. We also suggest that fermented ethanol extraction can be used to obtain stevia leaf extracts.

Suitability of Hot Water Extract from Panax ginseng Sprout Powder as a Dairy Additive

“…항산화능은 노화뿐만 아니라 다양한 질병의 원인이 되는 superoxide anion radicals, hydroxyl radicals, and hydrogen peroxide 등과 같은 활성산소(reactive oxygen species, ROS)를 제거 하여 체내에서 산화 스트레스(oxidative stress)를 완화시켜주는 능력으로 [2,3], 항산화 활성을 지닌 다양한 합성 및 천연 항산화제가 개발되어 사용되어오고 있다 [4]. 인삼(Panax ginseng)은 오가피나무과의 다년생 초본으로 사포닌, 폴리페놀, 폴리아세틸렌, 알칼 로이드 등이 다량 함유되어 있어 항산화 작용 [5], 동맥경화 및 고혈압 예방 [6], 항암작용 [7] 등 다양한 건강 증진 효과를 지니고 있다 [8].…”