A new method for the determination of carbohydrate content in starch samples by alkaline potassium persulfate digestion

In the present work, a novel method for the determination of carbohydrate content in starch samples was developed by using the alkaline potassium persulfate digestion. This method was used to determine the total carbon and nitrogen content of the starch samples. Based on the total nitrogen content, the protein content of the starch samples was computed, and the protein's carbon content was subtracted from the total carbon content to determine the starch samples' carbohydrate content. The test findings validated the capacity of the proposed method in quantifying the carbohydrate content in starch samples as well as its strong intra-day and daylight stability. The results obtained through this method were compared with those obtained through acid hydrolysis by measuring the carbohydrate content in 9 kinds of samples, yielding an intra-group correlation coefficient of 0.986 (P = 0.000, n = 9), and the 95 % confidence interval was 0.938–0.997. Comparison between the enzymatic method and the proposed method showed that the intra-group correlation coefficient was 0.976 (P = 0.000, n = 9), and the 95 % confidence interval was (0.608 ∼ 0.996). The standard addition recovery rate ranged from 95 % to 105 %, using 9.09×10⁻² mg/100 mg and 0.44×10⁻² mg/100 mg as the upper and lower detection limits, respectively.