Effects of Rosemary Extracts on Textural and Functional Qualities of Surimi Gel from Striped Catfish (Pangasianodon hypophthalmus) (Sauvage, 1878) during refrigerated storage

Abstract

Effects of aqueous and ethanolic extracts of rosemary
leaf on textural and functional properties of
surimi gel from striped catfish (Pangasianodon
hypophthalmus) (Sauvage, 1878) during refrigerated
storage was evaluated. The properties of surimi gel
such as gelling, water holding capacity, protein
solubility, texture profile, whiteness, as well as the
quality indices like total volatile bases and
thiobarbituric acid values were estimated periodically
during a refrigerated storage period of 20 days.
Increase of water holding capacity in rosemary
extract added gels indicated stronger protein network
formation, whereas, protein solubility decreased
significantly in all the groups as the storage
progressed indicating the formation of protein
aggregates. Thiobarbituric acid value, indicative of
lipid oxidation decreased in treated samples but at
different rates, depending upon the concentration of
rosemary extract. Gel strength of samples was
affected upon incorporation of rosemary extract and
treated groups showed higher values than the
control, indicating the positive role of rosemary’s
phenolics in cross linking of protein-protein interaction.
Textural attributes were found to be affected
most due to addition of rosemary. The control
samples tended to have the largest decreasing rate
of whiteness during the period of storage, compared
to the treated groups (0.25-0.75%). Both the extracts
of rosemary at higher concentration (0.75%) showed
highest consumer acceptability on day-1 and also at
the end of the storage period. On the basis of sensory evaluation the control was acceptable only upto 12 days.