The importance of the heat-induced modifications caused in milk by sterilization processes has been evaluated in 350 commercial samples by considering both the content of newly formed compounds (lactulose and furosine) and the content of soluble whey protein (α-lactablumin, β-lactoglobulin and blood serum albumin). Some physical indexes, such as the emission of chemiluminescence and the modification of surface-hydrophobicity of protein, have also been considered. The contents of lactulose and soluble whey protein seem to be the best parameters to described the heat damage in sterilized milk. Particularly, the lactulose content is closely related to the heat treatment and could be used to define the upper limit of heat damage for each class of sterilized milk (direct UHT, indirect UHT, in-bottle sterilized). The contents of soluble whey protein better describe the process conditions corresponding to slight modifications; the presence of soluble blood serum albumin could characterize the direct-UHT milk, while the denaturation of β-lactoglobulin and α-lactalbumin could identify the in-bottle sterilized milk. The use of these parameters allows the 3 types of sterilized milk to be characterized according to heat treatment severity; nevertheless, each type of commercial sterilized milk shows a high variability and therefore a very different quality. The high heat damage found in a considerable number of milk samples, both UHT and in-bottle sterilized milk, points to the use of excessive heat treatment conditions or repeated treatments. Also, for sterilized milk, new regulations to define the quality according to the heat damage are required.
|Titolo:||Evaluation of heat damage in UHT and in-bottle sterilized milk samples traded in Italy|
FOSCHINO, ROBERTO CARMINE (Ultimo)
|Settore Scientifico Disciplinare:||Settore AGR/15 - Scienze e Tecnologie Alimentari|
|Data di pubblicazione:||1990|
|Appare nelle tipologie:||01 - Articolo su periodico|