현재 시판되고 있는 5개사의 농후 발효유를 수집하여 이들의 물리화학적 특성과 저장중 변화를 관찰하였다. pH는 $3.87{sim}4.19$, 산도는 젖산량으로 $0.97{sim}1.4%$, 점도는 $7,850{sim}21,000Cp$ 범위였으며, 당도는 $16.2{sim}22.2$ Brix를 나타내고 있었다. $5^{circ}C$ 저장 중 pH 계속 강하하여 저장 16일에 pH4.1 내외에 이르렀고, 산도는 비례하여 상승하였으며 점도는 저장기간에 따라 증가하는 현상으로 보아 젖산균의 활동이 계속됨을 보여주었다. 젖산균은 초기 $10^8{sim}10^9CFU/ml$로 규정 이상이었고 저장중 일부 증가하거나 일정수준을 유지하고 있었다.
Gel type yoghurts from 5 representative manufacturers were collected at market and evaluated their physico-chemical properties during storage at $5^{circ}C$. The range of pH, acidity, Brix and viscosity of each product were $3.87{sim}4.19,;0.97{sim}1.42%,;16.2{sim}22.2;and;7,850{sim}21,000 cp$ respectively. The pH of each product decreased gradually during storage time and reached around pH 4.1 after 16 days with proportional acidity increasing. The viscosity of all test products showed increasing trend by lactic acid bacterial action. Total lactic acid bacteria were $10^8{sim}10^9;CFU/ml$ at the beginning storage and increased or decreased depending upon each product. But all product maintained over than $10^8 CFU/ml$ which meets regulatory level after 16 days storage.
