Sugar Determination in Dairy Products: Applications

> Sugar compounds in fruit yoghurt
> Mono- and disaccharides in baby food
> Sugar constituents in a protein concentrate
> Carbohydrates in milk

Sugar compounds in fruit yoghurt

Separation column: Metrosep Carb 1 - 250
Flow: 1 mL/min
Eluent: 100 mmol/L NaOH
Temperature: 30 °C

Results: 0.2 mg/g inositol; 0.8 mg/g sorbitol; 21.0 mg/g glucose; 7.4 mg/g galactose; 16.1 mg/g fructose; 26.5 mg/g lactose;
77.0 mg/g sucrose

Galactose, fructose and lactose were detected in baby food. 1 g of the sample powder was suspended in 1 L ultrapure water. The stock solution was subsequently diluted 1 : 10.

Separation column: Metrosep Carb 1 - 250
Flow: 1 mL/min
Eluent: 100 mmol/L NaOH
Temperature: 32 °C

Results: 45 mg/g galactose; 3.4 mg/g fructose; 536 mg/g lactose

Sugar constituents in a protein concentrate

Galactose and lactose were determined in a soluble, spray-dried whey-protein concentrate (2 g dry substance [ds] dissolved in 1 L ultrapure water, subsequently diluted 1 : 10).

Separation column: Metrosep Carb 1 - 250
Flow: 1 mL/min
Eluent: 100 mmol/L NaOH
Temperature: 32 °C

Results: 30 mg galactose / 100 g ds; 3816 mg lactose / 100 g ds

Mono-, disaccharides and sugar alcohols were analyzed in milk. The milk was diluted 1:1000. The precision of milk analysis with Metrohm Inline Dialysis was 1.52%.

Separation column: Metrosep Carb 1 - 250
Flow: 1 mL/min
Eluent: 100 mmol/L NaOH
Temperature: 32 °C

Results: 33 mg/L inositol; 19 mg/L xylitol; 4 mg/L arabitol; 47 mg/L arabinose; 44 mg/L mannose; 51 mg/L glucose; 36 g/L lactose