GB1043194A - Dehydrated fermented milk products - Google Patents

Abstract

A dehydrated milk product, particular yoghurt or kefir, comprises dehydrated curd, lactic acid and the typical flavouring materials present in the corresponding freshly fermented milk product, the proportions of lactic acid and of flavouring materials present in the dehydrated product being such that upon reconstitution of such product with a volume of milk substantially equal to the volume of aqueous liquid evaporated during dehydration, a product is produced having concentrations of lactic acid and the flavouring materials substantially equal to those of a similar freshly prepared conventional fermented milk product. In the production of a dehydrated yoghurt, the requisite concentration of flavouring materials for the dehydrated product may be achieved by: (i) inoculating milk with a starter strain comprising at least two known yoghurt-producing bacteria having different optimum fermentation temperatures and carrying out a part of the subsequent fermentation at substantially the optimum temperature for each bacterium, as exemplified by fermenting a mixed culture of Lactobacillus bulgaricus and Streptomyces thermophilus firstly at 37 DEG C and subsequently at 50 DEG C, (ii) using a greater proportion of inoculum and/or an enriched milk, exemplified by fermenting a mixed culture of L. bulgaricus and S. lactis at their optimum fermentation temperature of 37 DEG C, or (iii) including in the starter strain at least one bacterial strain e.g. of S. diacetylactis, S. cremoris and Betacoccus cremoris, which produces the typical flavouring substances of yoghurt but which is not conventionally used in its production, and carrying out a part of the subsequent fermentation at the optimum temperature for that bacterium. Usually the fermentations are carried to a point at which at least twice the normal content of flavouring materials has been produced in the fermented milk product. The requisite content of lactic acid is ensured by introducing a culture of innocuous lactic acid-producing bacteria either into the fermenting milk or into the fermented product, or by adding lactic acid either prior to, or during the dehydration. The fermented product may be homogenized under a pressure of 500 lbs.per sq.in.and dehydrated by spray-drying. Examples are disclosed.