engleski

Optimizing enzymatic hydrolysis of lactose in a sweet whey

Whey is a by-product of cheese production, containing more than 70% of lactose in dry matter. Certain percentage of adults have problems in digesting lactose, as they lack the enzyme called β -D-galactosidase. The problem can be resolved, or at least alleviated, employing enzymatic hydrolysis of the lactose. The hydrolysis of lactose yields two sugars – glucose and galactose, sweeter than lactose, easier to be fermented and digested in human digestive tract. The investigation presented deals with testing the conditions of lactose enzymatic hydrolysis in a sweet whey, with the aim of selecting an optimal procedure. The hydrolysis is performed employing the enzyme β -D-galactosidase, obtained from the yeast Kluyveromyces marxianus var. lactis, in the temperature range from 6 to 37 °C, using various concentrations of the enzymatic preparation, and at varying speeds of sample stirring. The results obtained show that, with the enzyme concentration of 2.5 mL L-1 and stirring speed of 600 rpm, at 6 °C, and after 10 hours, more than 90% of the lactose is hydrolysed, while at 37 °C, with the same stirring speed, 85-87% of the lactose is hydrolysed.

whey; hydrolysis of lactose

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