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A STUDY OF FORCE‐COMPRESSION CONDITIONS ASSOCIATED WITH HARDNESS EVALUATION IN SEVERAL FOODS
Author(s) -
BOYD J. V.,
SHERMAN P.
Publication year - 1975
Publication title -
journal of texture studies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.593
H-Index - 54
eISSN - 1745-4603
pISSN - 0022-4901
DOI - 10.1111/j.1745-4603.1975.tb01424.x
Subject(s) - crosshead , compression (physics) , materials science , composite material , mastication , indentation hardness , orthodontics , medicine , microstructure , flexural strength
. The hardness of fourteen foods has been evaluated by panel tests and by compression tests with a table model Instron. Oral evaluation of hardness was correlated with instrumental force ‐% compression data obtained for compressions extending up to 80% and with crosshead speeds up to 20 cm min −1 . With soft foods, agreement between panelists' and instrumental data commences at lower % compressions and lower applied forces than with hard foods. As the Instron crosshead speed increases so does the force required to achieve a desired % compression. With very hard foods exhibiting a short relaxation time, e. g. toffee, stress relaxation may influence the registered force. Crosshead speeds exceeding 20 cm min ‐1 ** cannot be utilised in conjunction with the standard Instron recorder because its response time is too long. It should be replaced by a fast response recorder such as a UV recorder. The procedure whereby panelists evaluate hardness during the first downstroke of mastication appears to change from compression to biting as hardness increases. A limited number of tests with Cheddar cheese and table jelly suggest that hardness evaluation by squeezing samples between the thumb and index finger involves lower % compression and lower forces than the oral evaluation of hardness with the same products.