ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The rates of various reactions associated with deterioration of whole dates such as darkening, pH decrease, sucrose hydrolysis, and oxygen and carbon dioxide gas exchange were studied at 28.4, 38.0, and 49.0°C and their apparent activation energies calculated. Also, changes in the activities of phenolase and peroxidase were followed in dates stored at 38.0°C. It was shown that dates darken by both oxidative and nonoxidative browning pathways, which respectively have apparent activation energies of 23.4 and 34.5 kcal/mole. Demonstration of enzymic browning in ground date tissue suggested that oxidative browning of whole dates is enzyme-catalyzed. Oxygen absorption and carbon dioxide production gave respective apparent activation energies of 17.6 and 25.3 kcal/mole in unheated dates, and 19.0 and 27.4 kcal/mole in heated dates, indicating the existence of enzymic and non-enzymic sources. The nonenzymic nonoxidative decrease in pH and invertase-catalyzed sucrose hydrolysis had apparent activation energies of 22.8 and 26.0 kcal/mole, respectively. Apparent phenolase activity increased during storage of dates, whereas apparent peroxidase activity decreased.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1961.tb00401.x
Permalink