J. Agric. Food Chem. 1903, 47, 968-972
088
pH Changes in Smokeless Tobaccos Undergoing Nitrosation during
Prolonged Storage: Effects of Moisture, Temperature, and Duration Roger A. Andersen,*JJ Pierce D. Fleming,?*$Thomas R. Hamilton-Kemp,g and David F. Hildebrandt Agricultural Research Service, U S . Department of Agriculture, and Departments of Agronomy and Horticulture, University of Kentucky, Lexington, Kentucky 40546-0091
Three smokeless tobacco research products were each adjusted to two moisture levels before storage for 48 weeks at 24 and 32 "C. The pHs of high water content moist snuff (55.5%) and dry snuff (remoisturized to 51.4 % ) increased 0.3-2.1 pH units during the storage. In contrast, the pHs of decreased water content moist snuff (21.9%) and dry snuff (12.3%)decreased by 0.2-0.4 unit. Chewing tobacco pHs at high (49.3%) and low (22.3%) moisture levels and at each moisture-temperature treatment decreased during storage. Nitrosated pyridine alkaloids increased only in tobaccos that became more alkaline during storage. Interactions between the effects of moisture and temperature occurred. Heating snuffs a t 100 "C for 30 min at zero storage time prevented the increases of pH, nitrosamines, and nitrite observed in non-heat-treated controls during storage. The results support the view that increases of nitrosamines may be mediated by microbial growth.
INTRODUCTION Nitrosated pyridine alkaloids related to nicotine are often referred to as tobacco-specific nitrosamines and may act as carcinogens (Hecht et al., 1986) or promoters of carcinogenicactivity (Johansson, et al., 1991). A previous study of moist snuff and dry snuff research products (Andersen et al., 1991) indicated that these nitrosamines generally accumulated at higher rates during storage at high moisture (ca. 50%) and high temperature (32 "C) compared to low moisture (
