Premium
Original article: Characterisation of water species revealed in the drying operation of Todarodes pacificus Steenstrup using water proton NMR analysis
Author(s) -
Konishi Yasuyuki,
Kobayashi Masayoshi,
Miura Kouichi
Publication year - 2010
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2010.02347.x
Subject(s) - proton , proton nmr , thermal diffusivity , relaxation (psychology) , water content , chemistry , analytical chemistry (journal) , squid , nuclear magnetic resonance , thermodynamics , stereochemistry , physics , chromatography , ecology , biology , engineering , geotechnical engineering , quantum mechanics , neuroscience
Summary For the discrimination of water molecules during the squid‐drying process, the water distribution was characterised by water proton NMR and moisture diffusivity ( De ) analysis methods as a function of the water content ( W 0 ). The proton NMR spectrum showed three peaks indicating three different species (species‐A, ‐B, and ‐C) distributed in the squid muscle, each of which had a characteristic behaviour of the relaxation time ( T 2 ) as a function of the W 0 . The 1/ T 2 of species‐A was drastically varied at W 0 = 120%‐d.b., indicating two further categories, i.e., species‐A 1 and ‐A 2 . Species‐A 1 is available at W 0 > 120%‐d.b. and was characterised as having De = 5.1 × 10 −10 m 2 s −1 , activation energy of moisture diffusivity ( E D ) = 17 kJ mol −1 , and relaxation rate 1/ T 2 = 74 s −1 , as evaluated by the proton NMR spectrum without depending on W 0 . Species‐A 2 is available at W 0 < 120%‐d.b., indicating a distribution of De = 4.8 × 10 −10 –1.7 × 10 −10 m 2 s −1 , E D = 25–35 kJ mol −1 and 1/ T 2 = 1.8 × 10 3 –1.5 × 10 2 s −1 with increasing W 0 . Species‐A 1 and ‐A 2 were assigned as weakly restricted water and strongly restricted water, respectively.