Effect of Polyphenols on Gel Strength of Alaska Pollock Surimi

Abstract

The effects of polyphenols on the texture of gels prepared from Alaskan pollock (Gadus chalcogrammus) surimi were investigated. The breaking force and strain of the polyphenol-containing gels were dependent on the type and amount of added polyphenol. Gels with 0.1% tannic acid, 0.1% gallic acid, 0.1% ellagic acid, 0.05% catechin, and 1.0% naringenin showed increased breaking forces compared with gels lacking added polyphenols. In contrast, supplementation with polyphenols decreases gel breaking force and strain. A comparison of catechins with different structures showed that the strength of reactivity was not proportional to breaking force. The number of free sulfhydryl groups in gels with gallic acid or catechins suggests that these polyphenols induce binding through sulfhydryl groups. Mass spectrometry imaging of the gel with gallic acid suggested the formation of protein-gallic acid complexes. The increase in the breaking force was inferred to be related to formation of cross-links and complexes between polyphenols and proteins through sulfhydryl groups. To control protein gel texture, selection of appropriate polyphenol and protein concentrations is important.