The Manufactures and Characteristics of Chestnut Yoghurt (The Volatile Flavour Compounds and the Sensory Properties of Chestnut Yoghurt)

밤 Yoghurt의 제조와 특성 (밤 Yoghurt의 휘발성 향미성분 및 관능적 특성)

The effects of the addition of raw and dried chestnut with levels of 1%($T_1$),2%($T_2$),3%($T_3$) and 4%($T_4$) in skim milk substrate on the volatile flavour compounds and sensory properties of yoghurt fermented with the mixed cultures of YC-380 and ABT-4 during fermentation and storage period were investigated. In all treatments, the contents of acetaldehyde and acetone were detected at 2 hrs. and 1 hr. of fermentation, respectively and decreased with the storage period. The contents of ethanol and diacetyl were detected in all treatments at 3 hrs. and 4 hrs. of fermentation, respectively and increased significantly(p<0.05) with the storage period. The contents of volatile flavour compounds of treatments were increased gradually with decreasing the level of addition of raw and dried chestnut, and increased in order of fermented with YC-380 and ABT-4. The contents of volatile flavour compounds of raw chestnut yoghurt were slightly high compared to those of dried chestnut yoghurt. The taste, flavour and texture of $T_1$ were slightly higher than those of all treatments immediately after fermentation and during the storage period. The scores of sensory evaluation of treatments except $T_1$ were lowered significantly(p<0.05) with increasing the level of addition of raw and dried chestnut. The quality of both of flavour and texture, and taste were superior to chestnut yoghurt fermented with YC-380 and ABT-4, respectively. Generally the scores of sensory evaluation of dried chestnut yoghurt were slightly high compared to those of raw chestnut yoghurt. From the results mentioned above, the addition of raw and dried chestnut at 1%(w/v) level in skim milk substrate were suitable for volatile flavour compounds and sensory property of raw and dried chestnut yoghurt.

YC-380 및 ABT-4의 혼합균주를 이용한 yoghurt 제조시 탈지유기질에 생밤 및 말린밤을 각각 1%(T1), 2%(T2), 3%(T3), 4%(T4) 수준으로 첨가가 발효기간 및 냉장 저장기간 동안 휘발성 향미성분 및 관능적 특성에 대하여 조사되었다. 모든구에 있어서 발효기간 및 저장기간이 경과함에 따라 acetaldehyde 및 acetone은 각각 발효 2시간 및 1시간째에 검출되어 저장 12일까지 점차 감소하였으며, ethanol 및 diacetyl은 각각 발효3시간 및 4시간째부터 검출되어 저장기간이 경과함에 따라 유의적(p<0.05)으로 증가하였다. 전 실힘구에 있어서 첨가수준이 낮을수록 유산균주별로는 YC-380 및 ABT-4순으로 함량이 높았으며, 대체적으로 생밤 첨가 yoghurt가 말린밤 첨가 yoghurt보다 높은 함량을 나타내었다. 관능검사 결과 냉장 저장기간 동안 실험구 71은 맛, 향 및 조직면에서 대조구 및 다른 실험구보다 다소 높은 점수를 나타내었다. 실험구별로는 첨가수준이 높을수록 낮았으며, 유산균주별로는 YC-380은 향과 조직면에서 ABT-4는 맛에서 각각 우수하였다. 대체적으로 말린밤 첨가 yoghurt가 높은 점수를 나타내었다. 이상의 결과 발효기간 및 냉장 저장기간 동안 생밤 및 말린밤 yoghurt의 제조에 있어서 탈지유 기질에 1%(w/v) 수준의 첨가가 휘발성 향미성분 및 관능성에 적합하였다.