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Direct heating of drying air with natural gas in the preparation of milk powder
Author(s) -
JANSEN L A,
ELGERSMA R H C
Publication year - 1985
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/j.1471-0307.1985.tb02748.x
Subject(s) - nitrite , chemistry , combustor , nitrate , nitrosamine , food science , organic chemistry , combustion , carcinogen
The question is considered whether in the production of milk powder direct heating of the drying air can be used as an alternative to indirect heating. Direct gas firing appears to result in substantial savings in the cost of energy and in capital expenditure. As compared with indirect heating, direct gas firing leads to the milk powder showing a slight increase in nitrate content (on average 8–14 mg/kg) and a marked increase in nitrite content (on average 0.4‐3 mg/kg). This level of contamination is expected to diminish when a “low NO x ” burner is used. Whereas in preliminary research into the presence of volatile N‐nitrosamines a level slightly above 1 μm N‐nitrosodimethylamine (NDMA)/kg powder was found, more recent experiments showed a maximum of 0.3 g NDMA/kg. There seemed to be no significant relation between the nitrosamine content of the product and the method of heating the drying air.