Fermentation to give allergen-free whey and dairy?
Streptococcus strain could selectively reduce the protein
responsible for cows milk allergy, researchers have reported.
Researchers at Germany's University of Hohenheim have reported that fermentation of skim milk and sweet whey with a one-to-one mixture of the bacteria could reduce the quantity of beta-lactoglobulin, the main allergen in cows milk, by as much as 90 per cent.
The research may also have implications for the wider food industry since whey and whey-derived ingredients are extensively used in a range of food products.
Whey proteins from cow's milk are used as emulsifiers in a broad range of food products including ice creams, beverages, salad dressing and sports supplements, and are classified as either concentrates (protein content between 25 and 80 per cent) or isolates (more than 90 per cent protein).
Whey also contains a range of other proteins, including alpha-lactalbumin, glycomacropeptide, serum albumin, immunoglobulins, lactoferrin and lactoperoxidase.
Writing in the journal Innovative Food Science & Emerging Technologies, the researchers state that by reducing the beta-lactoglobulin content of the dairy product, the allergic response to the dairy may be reduced by as much as 90 per cent.
"In more than 80 per cent of all cases, the whey protein beta-lactoglobulin (beta-lg) is the main elicitor of milk allergies for children and infants. Beta-lg is the major whey protein in milk and milk products and it is of particular interest because it is the sole whey protein fraction present in cow's milk which is not in human milk," explained lead author Nicole Kleber.
The researchers tested a wide range of lactic acid bacteria (Lactobacillus) independently or in combination with Streptococcus thermophilus subspecies salivarius on the beta-lg content of both sweet whey and skim milk.
The dairy was incubated with one per cent bacteria at 40 degrees Celsius for 24 hours.
The researchers report that the antigenicity of beta-lactoglobulin was significantly decreased with the majority of bacteria examined. Antigenicity refers to the capacity to induce an immune response. The enzymes are reported to be more or less specific with some better at reducing the beta-lg content in milk and/ or whey.
Kleber and her colleagues report that beta-lg antigenicity in the sweet whey was reduced by over 70 per cent, while skim milk had reductions of more than 90 per cent.
"These results are promising for new fermented milk products with reduced antigenic properties. In addition, synergism regarding the reduction of antigenicity was observed when using 1:1 mixtures of lactic acid bacteria with S. thermophilus subsp. salivarius strains," said the researchers.
However, the researchers stressed that only the antigenicity of beta-lg was tested while the actual allergenicity was not.
"Further research will be addressed to produce such products in pilot scale for clinical tests in order to test allergenicity or the allergy-reduced characteristic of the product," said the researchers.
The food intolerance and allergies market is growing rapidly as consumers focus increasingly on diet as a factor in their health. In the UK the sector has grown 165 per cent since 2000, according to market analysts Mintel, and is set to more than double in value by 2007 reaching £138 million (€202m).
Source: Innovative Food Science & Emerging Technologies Volume 7, Issue 3 , Pages 233-238 "Screening for lactic acid bacteria with potential to reduce antigenic response of beta-lactoglobulin in bovine skim milk and sweet whey" Authors: N. Kleber, U. Weyrich and J. Hinrichs
