Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Food Science and Technology

Major Professor

Melvin R. Johnston

Committee Members

Jimmie L. Collins, I.E. McCarty, H.A. Fribourg


This study was conducted to ascertain the effect of various commercial enzyme preparations and different heat treatments of date slurries on the chemical composition of and physical changes in the date juice.

Zahdi dates were pitted and blended with water (1:3, w/w) to a slurry consistency. Samples of the slurry were heated to different temperatures.

Five enzyme preparations were selected because of the favorable influence they exhibited on clarity and volume of the juice. Samples containing 0.2 percent enzyme preparations were held in a water bath at 55°C for 10 hours. The clarified juice was analyzed for percentage of soluble solids, invert sugars, nitrogen, and anhydrogalacturonic acid. The volume and clarity of the juice also were measured.

All chemical and physical characteristics were influenced by the addition of enzymes. Volume and clarity of juice were influenced more than the other variables.

The combinations of Pectinol and unheated slurry produced juice of a higher clarity value than all other enzyme-slurry treatments.

Heating the slurry to boiling produced an increase in the percentage of invert sugars, anhydrogalacturonic acid, and volume, as compared to slurries heated to 80°C, and unheated.

The highest percentages of invert sugars and volume were obtained from the slurry treated with the combination of carbohydrases.

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