Study on the methods to decrease cariogenicity of food stuffs

降低食品致酸性的方法被认为是降低食品致龋性最有效的方法。本研究的目的是评估这些物质的缓冲能力，特别是低分子壳聚糖（LMCS），以及葡萄糖溶液对变形链球菌细胞悬浮液产酸和人类斑块pH反应的影响。本研究采用五种具有缓冲能力的试验物质。此外，还制备了7种不同分子量和不同脱乙酰度的LMCS。本研究采用自动滴定法和ph下降实验对变形链球菌细胞悬浮液体外产酸进行了评价，并采用乳酸恒加法。体内产酸量通过离子敏感晶体管电极进行评估。在这项研究中获得了5名人类志愿者的数据。评价每个LMCS的作用由四个标准确定，1)面积（exp /cont）比低于pH 5.5, 2)时间（exp /cont）比低于pH 5.5, 3)最小pH， 4) pH。在pH 7.0的体外pH下降中，LMCS（pKa:6.4）和苹果酸盐（pKa:6.2）的作用最有效，pKa: 6.5左右。将五种LMCS（1%）添加到5%葡萄糖溶液中，可降低斑块pH值，并迅速恢复到静息值。当添加两种分子量分别为3000和500、DAC分别为50%和95%的LMCS时，效果最好。两种LMCS在四项指标上差异有统计学意义（p<0.01）。研究结果表明，低分子壳聚糖可作为食品添加剂降低食品的致酸性。

The methods to decrease acidogenicity of food stuffs have been considered to be most effective on decreasing their cariogenicity. The purpose of this study was to evaluate the effort of buffer capacity of the substances, especially low molecular chitosan(LMCS), in addition to a glucose solution upon acid production of S.mutans cell suspensions and human plaque pH responses.The five kinds of test substances having buffer capacity were used in this study. In addition, seven LMCS with different molecular weight and degree of deacetylation(DAC) were prepared for this study. Acid production in vitro were evaluated by the Automatic Titration Method and pH-fall experiment using S.mutans cell suspensions and also the constant addition method of lactate was used in this study. Acid production in vivo was evaluated by an ion-sensitive transistor electrode. Data from five human volunteers were obtained in this study. Evaluation of the effort of each LMCS was determined by four criteria, 1)area(exp./cont.) ratio below pH 5.5, 2)time(exp./cont.) ratio below pH 5.5, 3)minimal pH, 4) pH.The most effective effort on pH drop in vitro from pH 7.0 was obtained by the substances, ex. LMCS(pKa:6.4) and malate(pKa:6.2), with pKa:around 6.5. The additions(1%) of five LMCS to a 5% glucose solution decreased plaque pH drop and the pH returned rapidly to resting value. The most effective effort was obtained with the addition of two LMCS with MW:3,000 and 500, DAC:50 and 95%, respectively. The two LMCS resulted in statistically significant differences (p<0.01) in the four criteria.The findings indicate that low molecular chitosan is useful as a food additive to decrease acidogenicity of foods.