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ABSTRACTS
[Vol. XX, Part III
The Effect of a High Preheating Temperature with and without Ethyl Gallate on
the Storage Life of Whole Milk Powder Spray Dried on a Gray Jensen Drier.
WHITE, J. C. D., SMITH, J. A. B., and LEA, G. H. (1947). J. Dairy Res. 15, 127
A GRAY-JENSEN drier was used to prepare whole-milk powder from the same
bulk of raw milk, preheated to either 160°F. or 190°F. and storage studies
were made at two different centres under controlled conditions at 47°C., 37°C. and
15°C. and at room temperature, with and without the addition of ethyl gallate.
Besides determining the miosture, copper and ' readily extractable free fat'
contents of the milk powders, the flavour of the reconstituted milk, the oxygen
absorbed by the powders and their peroxide values were also estimated at different
stages of storage to evaluate their keeping properties.
It has been confirmed that the storage life of spray dried whole milk powder
could be extended by raising the preheating tempearture from 160°F. to 190°F.
but with the disadvantage of a ' cooked ' flavour in the reconstituted milk. The
addition of 0.07 per cent ethyl gallate at the lower preheating temperature of 160°F.
extended the life of the powder two to three times when stored at 37°C. However,
the low temperature preheated, gallate-treated sample speedily developed a rather
marked flavour and odour, similar to ' incipient tallowy ' taint and thus it has been
tentatively concluded that low temperature preheating plus ethyl gallate is not
to be preferred to high temperature preheating without ethyl gallate. It has been
established that use of the higher temperature for preheating and incorporation
of ethyl gallate extended the storage life of the powder considerably and is perhaps
to be preferred to high-temperature preheating and gaspacking for moderate periods
of storage. (A.K.)
The Properties of New Zealand Butters and Butterfats. (1) Iodine, Reichert
Samples of Butterfats from nine Commercial Factories over Four Years.
Cox, G. A. and McDOWALL, F. H. (1948). J. Dairy Res., 15, 377
T HE iodine, Reichert and saponification values and softening points of butter-
fats from butters collected at monthly intervals over a period of four years
from nine factories in New Zealand are reported. The trend of variations of any
one of the properties was remarkably uniform throughout a season and during
different seasons of the year and the same periodicity was noticed in all the four
years. But the maxima and minima for all the four properties studied did not
occur during the same season. The weighted monthly averages of iodine, Reichert
and sponification values and softening points of butterfats which have been cal-
culated rather than the straight average of the results obtained, have been found
to be 36.7 (33.8-40.2), 30.4 (25.5-32.3), 229.5 (225.5-232.7) and 33.1 (32.2-33.7)
respectively. The minimum iodine value occurred in midsummer, i.e. at the season
of the year when maximum values are reported for northern hemisphere butters.
South Island butterfats diverged markedly from those of the North Island samples
in having low iodine values during winter months, which may be due to the feeding
of turnips to the cows and consistently less softening points throughout the year.
The interrelationship of the different properties did not follow accepted lines and
explanation of this observation will have to await further detailed examination of the
fatty acids of butterfat during different seasons of the year. (A.K.)