Masters Theses

Date of Award

6-1973

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

J.L. Collins

Committee Members

M.R. Johnston, W.W. Overcast

Abstract

This study was designed to develop an intermediate moisture, high protein food product for human consumption. Pieces of sea catfish fillets were cooked in an infusion solution containing sorbitol, sodium chloride, sucrose, potassium sorbate, propylene glycol, monosodium glutamate, ribonucleotide and hickory smoke flavor. The infused pieces of flesh were breaded and deep fried to yield an intermediate moisture product of initial water activities of 0.760 and 0.800. The samples were stored in sterilized jars at 38°C for up to 4 months.

The storage stability study consisted of determining physical and chemical characteristics and microbial levels of the product at 15-day intervals for up to 4 months. Overall acceptance of the product was evaluated at 30-day intervals by using the hedonic-preference test. A difference-preference test was conducted to evaluate texture, moistness, and flavor.

For the product with initial water activity of 0.760, water activity decreased from 0.761 to 0.752, moisture content decreased from 22.59 percent to 21.09 percent, pH was lowered from 6.492 to 6.311, dominant wavelength decreased from 583.0 nanometers to 581.6 nanometers, thiobarbituric acid (TBA) values increased from 0.411 to 0.884, bacteria growth was not observed during storage, the yeasts and molds counts were 17, 3, and 3 at 0, 60, and 105 days' storage, respectively. Sensory evaluation of the product during storage showed that texture changed from "slightly tough" to "moderately tough", moistness decreased from "slightly dry" to "moderately dry", flavor was maintained between "like slightly" and "dislike slightly", overall acceptance was lowered from "like slightly" to "dislike slightly". When a sweet sauce was added, the overall acceptance was maintained at "like slightly" during storage. Analyses of freshly prepared samples showed that the product consisted of 38.30 percent crude proteins, 15.74 percent crude lipids, 5.79 percent ash (dry weight basis), 5.41 percent sodium chloride (wet weight basis), and 22.59 percent moisture.

For the product with initial water activity of 0.800, water activity decreased from 0.801 to 0.800, moisture content decreased from 26.60 percent to 24.87 percent, pH was lowered from 6.513 to 6.346, dominant wavelength decreased from 583.3 to 582.8 nanometers, TBA values increased from 0.242 to 0.986. Standard plate count of bacteria showed less than 300 bacteria per gram of sample at the first 15 days of storage and no growth after 15 days' storage throughout the final stage, yeast and mold growth were observed for the number of 43, 3, 23, 2, 2, and 3 at 0, 30, 60, 90, 105, and 120 days' storage, respectively. Panel tests showed that texture of the product was changed from "slightly soft" to "moderately tough", moistness was between "slightly dry" and "moderately dry", flavor was maintained at "like slightly", and overall acceptance had a trend from "like slightly" to less acceptable. When sweet sauce was added the acceptance was improved to between "like moderately" and "like slightly". Proximate analyses of freshly prepared samples showed that the product consisted of 36.52 percent crude proteins, 15.16 percent crude lipids, 5.81 percent ash (dry weight basis), 5.22 percent sodium chloride (wet weight basis), and 26.60 percent moisture.

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