ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
SUMMARY— The amount of alpha-amylase enzyme inactivated at the time-temperature recommended by the U.S. Public Health Service and by the U.S. Department of Agriculture for various liquid egg products was determined. The liquid whole egg, yolk, salted yolk or blended egg was placed in a stainless steel tube 40 in. in length and with an outside diameter of 0.125 in. The ends were closed and heated in a water bath for varying periods of time at different temperatures. The enzyme was assayed by the starch-iodine reaction method. When heated for 3.5 min, the amount of enzyme inactivated was 41 ± 5% for whole egg at 140°F; 27 ° 3% for yolk at 142°F; 100% for salted yolk at 146°F; 6 ° 2% for sugared yolk at 146°F and 0% for blended egg at 142°F. The D values at the respective temperatures were 19.6, 28.3, 0.68, 153.0 and 5,858 min. Addition of sucrose or Bactodextrin to egg modifies the alpha-amylase to become stabilized, and addition of sodium chloride modifies the enzyme to become susceptible to heat inactivation. Consideration of thermal inactivation data showed that the activation energy (92 to 132 Kcal mole−1) and entropy of activation (—238 to —313 Cal mole−1 K−1) were both high, indicating that enzyme inactivation will not become appreciable until much higher temperatures are reached. Data obtained on whole egg pasteurized by the commercial type batch and by the laboratory-type continuous-flow methods ware compared with those obtained above and were discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1970.tb00928.x
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