Assessment of whey protein nitrogen index as an indicator of heat treatment for UHT milk and milk powder
DOI:
https://doi.org/10.14295/2238-6416.v70i2.389Keywords:
Desnaturação, processamento térmico, qualidade, desidratação.Abstract
During heat treatment of dairy products it is possible to occur several chemical modifications which whey protein denaturation is quite evident and studied. This phenomenon can cause gelation in UHT milk and some problems in reconstitution of milk powder, two major dairy products widely used in dairy foods and by consumer. The whey protein nitrogen index (WPNI) can be an useful tool to assess the degree of severity that milk was submitted, and therefore inferred from the occurrence of possible defects associated with protein denaturation. This study presents the
evaluation of the non-denaturated whey protein contents as a heat treatment indicator for ultrapasteurization and drying milk processing. Commercial samples of UHT milk and milk powdershowed WPNI confidence interval of (2.39 ± 1.41) mgWPN.mL-1 and (2.63 ± 1.38) mgWPN.mL-1, respectively. According to the statistical analysis of variance, all samples differed with a p-value < 0.001; and 90% of UHT milk and 67% milk powder samples were classified as medium heat treatment. It was possible to infer the severity of the heat treatment associated with each kind of product analyzed.
The results were able to demonstrate the lack of standardization of heat treatment processes on the samples studied, a fact that may result in the growth of undesirable
characteristics in the products during the storage or commercia lization.
Downloads
Published
Issue
Section
License
Term of Responsibility and Transference of Author Rights
The undersigned authors of the article entitled "INSERT TITLE" declare to have read and approved all the manuscript. The authors agree to submit it to the Journal of Candido Tostes Dairy Institute for evaluation and possible publication as true, authentic, and original results. This statement implies that the manuscript, regardless of language, was not submitted to other journals with the same purpose. The authors acknowledge that will be required to provide retractions or corrections of errors related to the article, if necessary. The authors are aware of the guidelines and editorial policy of the Journal and assign copyright to the Journal of Candido Tostes Dairy Institute with the exclusive right to print, publish and sell the product worldwide, in all languages and media. Therefore, it is forbidden to authors reproduce wholly or partially the submitted manuscript in any other part or media, print or electronic. Thus, the authors declare that accepts to transfer the rights of graphic reproduction to the Journal of Candido Tostes Dairy Institute in the case of the article with the above title (or title that later come to be adopted, to meet the suggestions of the editors and reviewers) will be published in the Journal of Candido Tostes Dairy Institute. In addition, the authors agree to appoint _(name)___________ as the corresponding author.
This term should be signed by all authors in the order of authorship, stating:
Date;
Authors name without abbreviation;
Document number;
Title/position of each author;
e-mail; and
the area for evaluation of the paper.
