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Influence of fat reduction and whey protein concentrate addition on Prato cheese characteristics during ripening

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Author(s):
Lígia Dozena Domingos
Total Authors: 1
Document type: Doctoral Thesis
Institution: Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Defense date:
Advisor: Walkiria Hanada Viotto
Abstract

The objective of this study was to evaluate the influence of fat reduction and the addition of whey protein concentrate (WPC) on the texture and the formation of volatile compounds in Prato cheese during 210 days of refrigerated storage. This study also compared the colorimetric and chromatographic methods for the determination of diacetyl, which is associated with the buttery flavor and fresh cheese. Both methods showed significant Pearson correlation of 0.85 (p = 0.0036). The cheeses were manufactured in the full fat, reduced-fat and reduced-fat with added 0.5% whey protein concentrate (WPC) (w/v) versions. After 5, 15, 30, 60, 90, 120, 150, 180 and 210 days of refrigerated storage, the cheeses were evaluated for chemical composition, water mobility, proteolysis, texture and volatile compounds. The reduced-fat resulted in lower rates of proteolysis (p ? 0.05) and cheeses with higher hardness, cohesiveness, elasticity and chewiness (p ? 0.05). The addition of WPC did not cause significant changes in proteolysis (p > 0.05), and the cheeses presented a decrease of elasticity only from 120 days of ripening. The addition of WPC resulted in higher immobilized water content only until the fifth day of ripening. However, during the storage period, the percentage of immobilized water decreased and there was no significant difference between cheeses with and without CPS (p> 0.05). This indicates that there was an insufficient incorporation of whey proteins in the Prato cheese. Fat reduction and the addition of WPC influenced the concentrations of the main compounds formed, which were diacetyl, acetoin and sulfur compounds. The reduction of fat resulted in a higher concentration of diacetyl and acetoin at 5 days of storage (p ? 0.05) while the addition of WPC resulted in a higher concentration of diacetyl at 15 days of ripening (p ? 0.05). The addition of WPC resulted in higher concentrations of dimethyl disulfide at 150 and 180 days (p ? 0.05), and higher concentrations of dimethyl trisulfide after 150 days of storage (p ? 0.05). Changes in the concentration of volatile compounds in cheese appear to be related to changes in protein structure and polarity of the matrix caused by the reduction of fat and addition of whey protein concentrate (AU)

FAPESP's process: 09/54119-3 - Acquisition of a gas chromatograph mass spectrometer for the identification and quantification of compounds of interestin food quality and human health
Grantee:Neura Bragagnolo
Support type: Multi-user Equipment Program