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Enhancing the sweetening power of lactose by enzymatic hydrolysis and partial isomerization of the glucose moiety
Project
Project code: MRI-MF-08-155 - 1005-686 31-2093Lactosesüßkraft
Contract period: 01.07.2016
- 30.06.2018
Purpose of research: Experimental development
Dairy products contain up to 20% total sugar. About 4-6% of this sugar is the milk sugar lactose, which hardly contributes to the total sweetness of these products. However, lactose hydrolysis (LH) by the enzyme ß-galactosidase can be implemented to split lactose into glucose (Glu) and galactose, therewith increasing the sweetness of lactose. Own previous studies have shown that this sweetness can be further increased if the resulting Glu moiety is partially converted to fructose by the Glu-Isomerase (GI) enzyme. The relative sweetness can be increased up to 4-fold. With this process, the total sugar content of dairy products with the same sweetness could be decreased. This study investigated whether this bi-enzymatically modified milk is suitable for the production of dairy products, using yogurt and pudding as example products both in the MF pilot plant and in an industrial pilot plant. For yogurt production, the ability of different starter cultures (containing Streptococcus, Lactobacillus and Bifidobacterium strains) to ferment the altered sugar combination was studied. The biodiversity of both starter as well as non-starter lactic acid bacteria during fermentation and storage was determined by means of denaturing gradient gel electrophoresis and 16S rRNA high-throughput sequencing.
Through bi-enzymatic cleavage, sugar syrup comprised of 50% galactose, 25% glucose and 25% fructose was produced, tasting sweet with a hint of caramel. For the production of dairy products, the lactose component of milk was removed by means of membrane filtration and replaced by the sugar syrup. After optimization of production parameters, this enzymatically modified milk was used to produce yogurt and pudding products in our pilot plant. All products underwent sensory evaluation. It was observed that all strains implemented for yogurt production behaved similarly in both enzymatically modified and unmodified control milk with regards to microbial growth and milk acidification during fermentation and storage. Enzyme-modified milk did not encourage growth of pathogenic or food spoilage bacteria, and microbial biodiversity during fermentation and storage was similar to that in control milk. Yogurt produced with enzymatically-sweetened milk in a pilot setting was judged by a consumer panel as creamier and having a more distinct smell and taste than regular yogurt. Trial experiments on a larger-scale (industrial production) for both yogurt and pudding are absolutely necessary in order to fully assess the potential of the bi-enzymatic process of lactose modification.
Section overview
Subjects
- Food Chemistry
- Food Processing
- Biotechnology
Framework programme
Funding programme
Excutive institution
MRI - Department of Safety and Quality of Milk and Fish Products (MRI-MF)
