固定pH法连续测定齿果酸模中的总酸度和粗蛋白  

Continuous Determination of Total Acidity and Crude Protein of Rumex dentatus Whole Plant by Fixed pH Method

作　　者：朱盈蕊[1] 高向阳[1] 马紫英[1] 

机构地区：[1]河南农业大学食品科学技术学院,河南郑州450002

出　　处：《食品科学》2011年第22期204-208,共5页Food Science

基　　金：河南省重点学科建设项目(10466-X-082301)

摘　　要：为建立一种连续测定齿果酸模中总酸度和粗蛋白含量的新型方法,利用超声波辅助-中性甲醛提取酸性物质,以KOH溶液为标准溶液,用固定pH法滴定样液总酸度并除去过量甲醛后,加入浓硫酸消解完全,中和过量硫酸后用甲醛将NH4+转化为H+,以KOH标准溶液用固定pH滴定法连续测定粗蛋白含量。结果表明:干基样品总酸度(H+)为0.9178mol/kg,相对标准偏差<5%(n=6)。干基样品粗蛋白含量为15.30g/100g,相对标准偏差<3%(n=6),与国标法对照,测定粗蛋白没有显著性差异。该法操作简单、快速、方便,试剂用量少,工作效率大大提高,利于推广应用。A new fixed pH method for the continuous determination of total acidity and crude protein in Rumex dentatus whole plant was established.The acids in samples were extracted by formaldehyde with the aid of ultrasound,and a fixed pH titration method was used to determine the total acidity using KOH as a standard solution.After the determination of the total acidity,the excessive formaldehyde in the sample solution was removed and then digested with concentrated sulfuric acid.The extra sulfuric acid was neutralized and the NH4＋dissociated into H＋ by formaldehyde.The crude protein was determined by fixed pH titration method using KOH as the standard solution as well.The total acidity（H＋） of a dried sample was 0.9178 mol/kg with a relative standard deviation less than 5%（n= 6）,and the crude protein was 15.30 g/100 g with the relatively standard deviation less than 3%（n = 6）.These results indicated no obvious difference from those determined by the national standard method.In conclusion,the method has been proven to has many advantages such as simplicity,rapidity,easy operation,low regent consumption,short assay time,thus deserving to be popularized.

关 键 词：齿果酸模 固定pH法 总酸度 粗蛋白 连续测定 

分 类 号：O657.92[理学—分析化学] TS201.4[理学—化学]