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Molecular interactions and structural changes during "requeijão cremoso" processing with phosphates of diferent chains length

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Author(s):
Diogo Maus
Total Authors: 1
Document type: Doctoral Thesis
Institution: Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Defense date:
Advisor: Walkíria Hanada Viotto
Abstract

Sodium phosphates, with different chain lengths, are widely used as emulsifiers in the manufacture of processed cheese for casein stabilization. Phosphate chain length affects casein dissociation, fat emulsification, new protein interactions, and thus the texture and functionality of processed cheese. The production of processed cheese includes cooling and heating stages that could influence the phosphates chain length, on account of hydrolysis reactions caused by heat treatment, pH and ionic environment. This work aims to evaluate the chain length effect (n=2 to n=30) on hydrolysis phosphate during the fabrication of requeijão cremoso and its effects on chemical composition, particle size, zeta potential, insoluble calcium, water mobility, texture properties and requeijão microstructure. The work was divided in two stages: 1) chain lengths effect on phosphates hydrolysis in water, milk and calcium caseinate assessed by 31P nuclear magnetic resonance spectroscopy; 2) phosphate chain lengths effect on molecular interactions and structural changes of requeijao. In the first stage 3 sodium phosphate salts with increasing chain size were used: tripolyphosphate (TPS n=3), hexametaphosphate (HMPS n>10) and SELF B4 (n=30), assessing the variation on phosphate chain according to cooling and heating process. In the second stage 5 phosphate salts were used: tetrasodium pyrophosphate (n=2), tripolyphosphate (n=3), hexametaphosphate (n=2-10), Heidel phosphate (n=2-15) and SELF B4 phosphate (n=2-30). The hydrolysis degree of phosphates in calcium caseinate (TPS 6,7% pH 7,61; HMPS 7,5% pH 6,80 e SELF B4 7,2 % pH 6,53) were less intense when compared to water and milk indicating that, the higher the buffering power of the matrix, the lower the pH variation and the percentage of phosphate hydrolysis. Requeijão produced with long chain phosphates presented lower insoluble-calcium content and lower water immobilization capacity resulting in a less firm texture of requeijao. It is probably on account of a lower content of tetrasodium pyrophosphate, resultant of hydrolysis process, present in that requeijao at the end of processing. Therefore, the control of initial pH of processed cheeses is an essential factor for the control of hydrolysis rate and, the presence of tetrasodium pyrophosphate seems to control the texture properties of processed cheese by affecting the water immobilization, altering the structure of the product at processing and cold storage (AU)

FAPESP's process: 14/07291-3 - Molecular interactions and structural changes during processing of requeijão cremoso with polyphosphates of different chain lengths
Grantee:Walkiria Hanada Viotto
Support type: Regular Research Grants