Taurine과 환원당의 가열 반응 시 생성되는 nitrogen-, sulfur- and oxygen-containing compounds

Abstract

본 연구에서는 sulfonic acid기를 가진 아미노산인 taurine과 환원당인 xylose glucose, fructose를 가열 반응하여 이 때 생성되는 nitrogen-, sulfur- 및 oxygen-containing compounds의 생성을 고찰하였다. Xylose, glucose, fructose 세 가지 환원당과 taurine을 120, 150, 180℃에서 가열 반응 시 생성되는 nitrogen-, sulfur- 및 oxygen-containing compounds를 비교하였고, pH의 영향을 살펴보기 위해 반응 전 pH를 3, 7, 10으로 조절한 후 생성된 nitrogen-, sulfur- 및 oxygen-containing compounds를 살펴보았다. 세 가지 서로 다른 환원당의 가열반응에서 11개의 nitrogen-containing compounds, 2개의 sulfur-containing compounds, 20개의 oxygen-containing compounds가 생성됨을 확인하였다. 특히, nitrogen-containing compounds 중 2-methoxy-5-methyl pyrazine은 xylose와 fructose의 반응물에서 다량으로 생성되었으며, sulfur-containing compounds는 xylose와 glucose의 반응물에서 형성되었다. oxygen-containing compounds 중 furfural이 xylose에서 가장 많이 생성되었고 glucose, fructose 순으로 생성된 반면에 5-methyl furfural은 glucose, fructose에서 xylose에서보다 함량이 높았다. 전체적으로 세 가지의 반응물에서 생성된 nitrogen, sulfur and oxygen-containing compounds는 xylose >> glucose > fructose의 순서로 정량 및 정성적 차이를 나타내었다. 2) 120℃, 150℃, 180℃의 서로 다른 반응온도에서 가열반응 시 생성되는 nitrogen, sulfur and oxygen-containing compounds는 반응온도가 높아짐에 따라 그 종류와 함량이 급격히 증가하는 경향을 보였다. 120℃로 가열 시 xylose 반응물에서만 furfural이 동정되었고, 150℃에서는 xylose 반응물에서 2-methoxy-5-methyl pyrazine, dimethyl trisulfide, furfural 등이 동정되었다. 서로 다른 온도에서 반응 시 모든 환원당에서 공통적으로 생성된 성분은 furfural이었다. Xylose와 반응 시 낮은 온도에서도 가장 반응이 활발함을 볼 수 있었고 150℃에서는 fructose의 반응물에 비해 glucose에서 향미성분이 더 많이 생성이 증가되었다. 온도가 증가함에 따라 oxygen-containing compounds 중 furan류와 nitrogen-containing compounds의 생성량이 급격하게 높아졌다. 3) pH를 3, 7, 10으로 조절 후 가열 반응 시켰을 때 pH 3에서는 sulfur-containing compounds와 oxygen-containing compounds가 주로 동정되었다. 특히, furfural이 다량으로 정량되었고 sulfide 이외에 thiophene류와 thiazole류 같은 sulfur-containing compounds도 동정되었다. pH 7에서는 pH 3에서보다 nitrogen-containing compounds는 증가한 반면, sulfur- 및 oxygen-containing compounds는 감소하였는데 2-methoxy-5-methyl pyrazine이 pH3에 비해 모든 당에서 4배 이상으로 증가되었고, furan류는 정성 및 정량적으로 감소하였다. pH 10에서는 nitrogen-containing compounds가 다량으로 동정되었으며, pyrazine류, pyridine류, pyrrole류 및 pyrazole류가 확인되었다. 특히, 2,5-dimethyl pyrazine, trimethyl pyrazine과 2-methoxy-5-methylpyrazine의 함량이 높았다. 그러나 sulfur-containing compounds은 동정되지 않았으며, oxygen-containing compounds는 glucose와 fructose에서만 동정되고, xylose에서는 동정되지 않았다.;In this study, the formation of nitrogen-, sulfur-, and oxygen-containing heteroatomic compounds from the thermal reactions of taurine, an amino acid which has a sulfonic acid, with reducing sugars, such as xylose, glucose, and fructose, was investigated. To study the effects of reducing sugars (xylose, glucose, and fructose), reaction temperature (120, 150, 180℃), and pH (3, 7, 10) on the formation of nitrogen-, sulfur-, and oxygen-containing compounds, the volatile compounds formed were compared under different reaction conditions. The volatile compounds obtained from the thermal reactions of taurine with reducing sugars at 180 ℃ for 2 hr included 11 nitrogen-containing compounds, 2 sulfur-containing compounds, and 20 oxygen-containing compounds. In particular, a considerable amount of 2-methoxy-5(or 6)-methyl pyrazine was formed by thermal reactions of taurine with the three reducing sugars studied, whereas sulfur-containing compounds, such as dimethyl disulfide and dimethyl trisulfide, were found in the thermal reactions of taurine only with xylose and glucose. Also, the formation of furfural, which was a major compound in the thermal reactions of taurine with the three reducing sugars, was larger in the reaction of taurine with xylose than glucose and fructose at 180 ℃. On the other hand, the formation of 5-methyl furfural was increased in the thermal reactions of taurine with glucose and fructose compared to that of taurine with xylose. On the whole, the formation of volatile compounds studied was the largest in the thermal reactions of taurine with xylose at 180 ℃, qualitatively and quantitatively, followed by glucose and fructose. The number and amount of volatile compounds formed from the thermal reactions of taurine with reducing sugars were enhanced significantly according to reaction temperature when heated at 120, 150, and 180℃ for 2 hr. At 120 ℃, furfural was formed in the thermal reaction of taurine only with xylose, but not with glucose and fructose. 2-Methoxy-5(or 6)-methyl pyrazine was produced in the thermal reaction of taurine with xylose and fructose, whereas dimethyl trisulfide was identified in thermal reaction of taurine only with xylose at 150 ℃. More diverse and higher amounts of sulfur-containing compounds, sulfides, thiophenes and thiazoles and oxygen-containing compounds, furans, could be formed at pH 3. The formation of nitrogen-containing compounds, such as pyrazines, pyrroles, pyrazoles and pyridines, could be significantly enhanced at higher pH. Especially, the formation of 2-methoxy-5(or 6)-methyl pyrazine.