비파를 첨가한 stirred yoghurt를 제조하기 위하여 비파 착즙액 $15\%$를 Skim milk에 첨가하여 Streptococcus thermophilus 와 Lactobacillus acidophilus 혼합균주로 발효시킨 발효유에 비파 과육 첨가량 $(5\%,;10\%,;15\%,;w/v)$과 올리고당 첨가량 $(10\%,;15\%,;20\%,;25\%,;w/v)$을 달리하여 제조한 stirred yoghurt의 품질 특성을 조사하였다. 관능검사 결과에서는 비파 과육 $15\%$와 올리고당 $20\%$를 첨가하였을 때 단맛, 신맛과 전체적인 기호도에서 가장 좋게 평가되었다. 색도 측정 결과 비파 과육 $15\%$ stirred yoghurt에 올리고당의 첨가량이 증가할수록 명도(L값)와 적색도(a값)는 감소하였고 황색도(b값)는 증가하였다. Texture 특성은 $15\%$ 비파 과육 첨가 stirred yoghurt에 올리고당 $20\%$ 첨가시 견고성(hardness), 탄성(springiness), 응집성(cohesiveness), 껌성(gumminess)과 탄력성(resilience)등에서 가장 높게 나타났다. 따라서 $15\%$비파 착즙액 첨가 발효유에 $15\%$비파 과육과 $20\%$ 올리고당의 첨가가 비파 첨가 stirred yoghurt 제조를 위해 가장 적합한 것으로 사료되었다
This study was performed to develop a functional stirred yoghurt prepared from skim milk added with loquat(Eriobotrya japonica Lindley). Skim milk containing $15\%$ loquat extract was fermented by the mixed strains of Streptococcus thermophilus and Lactobacillus acidophilus, and then loquat flesh and oligosaccharide were added to the yoghurt base. Sensory scores of the stirred yoghurt containing $15\%$ loquat flesh and $20\%$ oligosaccharide were higher than other groups in sweet taste, sour taste and overall acceptability. When the levels of oligosaccharide of the stirred yoghurts added with $15\%$ loquat flesh were increased, the L value(brightness) and a value (redness) of the stirred yoghurt decreased, but the b value(yellowness) increased. The hardness, springiness, cohesiveness, gumminess and resilience of the $15\%$ loquat flesh stirred yoghurt added with $20\%$ oligosaccharide were higher than others.
