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A Simple Technique to Improve the Firmness of Cooked Potato Tissue
Author(s) -
Ramana Sundara V,
Stengel Eckehard,
Wolf Walter,
Spiess Walter E L
Publication year - 1997
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199707)74:3<340::aid-jsfa808>3.0.co;2-4
Subject(s) - turgor pressure , plasmolysis , mannitol , chemistry , food science , boiling , horticulture , botany , cell wall , biochemistry , biology , organic chemistry
Abstract Potato tissue samples with varying cell turgor pressures were prepared by soaking in mannitol solutions (0 to 0·5 M ). Increased concentration of mannitol in the soaking solutions decreased the cell turgor pressure in potato tissues providing samples with varying degrees of turgidity or plasmolysis. Firmness changes in potato tissues of differing turgor pressure during cooking were examined using a Zwick universal testing machine and also by chewing tests. A modified device attached to a Zwick machine facilitated complete immersion of a potato disc in circulating boiling water, providing rapid and reproducible heat transfer in the tissue during firmness measurements. Tissue firmness expressed as the force required to cause 10% strain in the sample varied in potato discs treated with differing mannitol solutions. Potato discs soaked in 0 to 0·3 M mannitol solutions were more turgid at 20°C than other samples and showed higher tissue firmness. However, when discs of potato were heated in the range of 20–90°C, samples treated with 0·4 and 0·5 M mannitol solutions showed some increase in tissue firmness while all other samples exhibited a rapid decline. Bite‐force measurements on potato discs also indicated a rapid loss of tissue firmness in turgid samples. Potato tissues when cooked after soaking in 0·4 or 0·5 M mannitol solution showed more intact and inflated cells than other samples. © 1997 SCI