DENMARK – Researchers at the National Food Institute, Technical University of Denmark (DTU) have developed a yogurt bacterium that can be used to produce naturally sweet yogurt, a milestone in the production of flavored yogurt without added sugars.
The lactic acid bacterium is a mutated dairy strain of the streptococcus thermophiles bacterium– which is a fast-growing lactic acid bacterium – that can catalyze hydrolyzing lactose when combined with lactase.
Often, fruit like berries or sweeteners like sugar is added to yogurt to improve taste and increase sweetness. However, consumers are increasingly demanding natural foods with less added sugar.
The researcher saw the possibility of creating natural sweetness in yogurt with less added sugar when using lactase derived from the lactic acid bacterium.
The results are published in the scientific journal article “Consolidated Bioprocessing in a Dairy Setting–Concurrent Yoghurt Fermentation and Lactose Hydrolysis without Using Lactase Enzymes,” in the Journal of Agricultural and Food Chemistry.
Lactose is the naturally occurring sugar component of milk, with a round 50g of lactose contained per 1l of milk.
By breaking down lactose of about 70%, they release more sweet sugars, e.g. galactose and glucose, by about 20g per liter of irregular sugar.
The process is used in yogurt and cheese production and typically requires manufacturers to source lactase enzymes separately.
Commercially available lactase enzymes, currently used for breaking down lactose in milk products are made using microorganisms, which involves a tedious and costly purification process.
Furthermore, transportation from the manufacturer site to the dairy adds to the costs, which can make the production process more costly and less sustainable.
The researchers underscored that the lactic acid bacteria-based lactase can be grown and used directly at the dairy and in the milk that ends up being yogurt, reducing the costs for purchasing the lactase and transportation.
The scientists screened the mutated strain for variants with higher beta-galactosidase activity to find out if the lactic acid bacteria-based lactase could break down milk sugar more efficiently.
Two isolates were identified, both of which could break down lactose without the need for another catalyst, thus proving the bacterium could be grown at the dairy and in the milk.
Christian Solem, Associate Professor at DTU’s National Food Institute said: “The solution is currently not intended for making 100% lactose-reduced dairy products, although I envision that future improved versions easily could manage to do that. However, additional funding is needed if we are to develop it further,”
“We aim for increased sweetness, where I think the potential is large. Some additional sweetness is probably needed, but less added sugar should be good as well…Our approach works and it can easily be made even better. The potential is immense and deserves investigations.”
The added sugar reduction solution could be a handful to US-based yogurt makers in fulfilling the new dairy regulation claim.
The Food and Drug Authority has introduced a new definition of ‘healthy’, under which dairy products that contain more than 2.5g of added sugars won’t be able to claim the status.
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