HYGROSCOPIC EQUILIBRIUM AND TEXTURE OF FREEZE-DRIED FOODS

Abstract

Improved methodology for the objective evaluation of food texture was applied to the measurement of the textural parameters of special freeze-dried foods which were storage-equilibrated under different relative humidity conditions. The foods included pre-cooked freeze-dried beef, laminated freeze- dried products in the form of bite-size sandwiches, and compressed freeze-dried cubes, all of which were designed for consumption without prior rehydration. The results showed that increasing relative humidity from zero to 66% caused an increase in hardness and cohesiveness, and, in certain foods, a decrease in brittleness (crushability index). This was more pronounced at equilibrium points above the B.E.T. value for a monomolecular layer of water. Plots of physico-chemical parameters of water vapor sorption versus rheological properties at different points of the moisture sorption isotherm were examined. The selection of certain 'target' relative humidity values to minimize undesirable changes upon storage, and promising avenues for continued work on the textural quality and acceptability of special freeze-dried foods are discussed.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1967
Accession Number
AD0655488

Entities

People

  • John G. Kapsalis

Organizations

  • United States Army Soldier Systems Center

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Chemistry
  • Connecting Rods
  • Data Analysis
  • Dehydrated Foods
  • Dry Materials
  • Energy
  • Food
  • Freeze Dried Foods
  • Humidity
  • Isotherms
  • Measurement
  • Moisture Content
  • Rods
  • Sorption
  • Statistical Analysis
  • Test And Evaluation
  • Water Vapor

Fields of Study

  • Agricultural and Food sciences

Readers

  • Aerosol Science/Aerosol Physics
  • Gender and Food Studies
  • Mechanical Engineering/Mechanics of Materials.