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Properties of whey protein-based films containing organic acids and nisin to control Listeria monocytogenes
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Orientador(es)
Resumo(s)
Whey protein isolate and glycerol were mixed to form a matrix to incorporate antimicrobial agents and produce edible films
with antimicrobial activity against Listeria monocytogenes strains isolated from cheeses. Various organic acids were used to
decrease pH down to approximately 3. In a preliminary assay without nisin, the effect of each organic acid was evaluated with
respect to the rheological properties of the film solutions and the inhibitory and mechanical properties of the films. Lactic, malic,
and citric acids (3%, wt/vol), which were used in a subsequent study of their combined inhibitory effect with nisin (50 IU/ml),
had significantly higher antilisterial activity (P , 0.05) compared with the control (2 N HCl, 3% [wt/vol], with nisin). The largest
mean zone of inhibition was 4.00 6 0.92 mm for malic acid with nisin. Under small-amplitude oscillatory stress, the proteinglycerol-
acid film solutions exhibited a predominantly viscous behavior or a weak gel behavior, with the storage modulus (G9)
slightly higher than the loss modulus (G0). The malic acid–based solution was the only one whose viscosity was not influenced
by the addition of nisin. The addition of nisin resulted in a nonsignificant (P . 0.05) increase in the percentage of elongation at
break. Results from tensile and puncture stress were variable, but in general no significant differences were found after the
incorporation of nisin. The overall results support the use of malic acid with nisin to produce effective antimicrobial films to
control L. monocytogenes growth.
Descrição
Palavras-chave
whey protein edible films nisin organic acids Listeria monocytogenes antimicrobial films
Contexto Educativo
Citação
"Journal of Food Protection". ISSN 0362-028X. 72(9) (2009) 1891-1896
Editora
International Association for Food Protection