Physicochemical Characteristics of Fermented Milk Containing Mulberry Leaf Extract

뽕잎추출액을 첨가한 발효유의 이화학적 특성

This study was carried out to evaluate the physicochemical characteristics of fermented milks containing mulberry leaf extract. The mulberry leaf extracts were added to fermented milk at $0{\sim}2.0%$. The pH, acidity, numbers of viable cells, chemical composition and color values of fermented milk preparation were analyzed, and these samples were subjected to a taste test panel. As the ratio of mulberry leaf extract increased, the pH value of the fermented milk decreased proportionally and acidities increased significantly. The numbers of viable cells was highest in the fermented milk sample containing 0.5% mulberry leaf extract. In the chemical composition analyses, increases in the concentration of mulberry leaf extract led to a significant increase in crude protein, crude fat, and crude ash contents and a significant decrease in lactose content. Ca, Mg and K in the fermented milk were also significantly increased with the addition of mulberry leaf extract. As mulberry leaf extract amount increased, the lightness and redness values decreased, while the yellowness value increased. From the sensory evaluation of the fermented milk containing mulberry leaf extract, color, taste, texture and overall acceptability of the fermented milk sample containing 1% mulberry leaf extract was found to be much better than those of the other groups.

뽕잎추출액을 첨가한 발효유의 이화학적 특성을 분석한 결과, pH는 배양시간이 경과함에 따라 뽕잎추출액 첨가군의 pH가 낮아졌으며, 산도는 발효유의 뽕잎추출액 첨가 농도가 증가함에 따라 증가하였다. 생균수는 뽕잎추출액 0.5% 첨가군의 생균수가 가장 많았고, 뽕잎추출액의 첨가량에 따라 무지유고형분, 조단백질, 조지방 및 조회분 함량은 증가하였으며, 수분과 lactose 함량은 유의하게 감소하였다(p<0.05). 무기질함량에서는 칼슘, 마그네슘, 칼륨 함량이 뽕잎추출액 첨가군에서 유의하게(p<0.05) 증가하였고, 색도는 발효유의 뽕잎추출액 함량이 높을수록 L값과 a값은 낮았으며 b값은 증가되었다. 관능검사에서 색은 뽕잎추출액 1.0% 첨가군에서 가장 높았으며, 향미는 뽕잎추출액 0.5% 첨가군이 가장 높았고, 맛과 질감은 뽕잎추출액 1.0% 첨가군이 가장 높아 전체적인 기호도에서 뽕잎추출액 1.0% 첨가군이 높게 나타났다. 따라서 뽕잎추출액을 첨가한 발효유의 이화학적 특성과 관능적 특성을 분석한 결과 뽕잎추출액 1%를 첨가한 발효유가 가장 적합하였다.