Composition and calcium status of acid whey from pasteurized, UHT-treated and in-bottle sterilized milks

Carbonaro, Marina; Lucarini, Massimo; Lullo, G. Di

doi:10.1002/1521-3803(20001201)44:6<422::aid-food422>3.0.co;2-d

Cited by 5 publications

(1 citation statement)

References 14 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 2 most commonly used pasteurization processes today are HTST and UHT. In the HTST process, milk is heated to a minimum of 72°C for 15 s, whereas the UHT pasteurization holds the milk at temperatures in the range of 135 to 140°C for a minimum holding period of 2 s. The effect of thermal pasteurization on milk including the quality of protein, fats, minerals, vitamins, appearance, and flavor has been a subject of intense research in the past few decades (Gregory, 1967;Ford et al, 1969;Douglas et al, 1981;Farrell and Douglas, 1983;Burton, 1988;McMahon et al, 1993;Ryley and Kajda, 1994;Li-Chan et al, 1995;Rattray et al, 1997;Carbonaro et al, 1997Carbonaro et al, , 2000Lacroix et al, 2006;Cattaneo et al, 2008;Al-Attabi et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Effect of homogenization and pasteurization on the structure and stability of whey protein in milk

Ren

Xiao

et al. 2015

Journal of Dairy Science

View full text Add to dashboard Cite

The effect of homogenization alone or in combination with high-temperature, short-time (HTST) pasteurization or UHT processing on the whey fraction of milk was investigated using highly sensitive spectroscopic techniques. In pilot plant trials, 1-L quantities of whole milk were homogenized in a 2-stage homogenizer at 35°C (6.9 MPa/10.3 MPa) and, along with skim milk, were subjected to HTST pasteurization (72°C for 15 s) or UHT processing (135°C for 2 s). Other whole milk samples were processed using homogenization followed by either HTST pasteurization or UHT processing. The processed skim and whole milk samples were centrifuged further to remove fat and then acidified to pH 4.6 to isolate the corresponding whey fractions, and centrifuged again. The whey fractions were then purified using dialysis and investigated using the circular dichroism, Fourier transform infrared, and Trp intrinsic fluorescence spectroscopic techniques. Results demonstrated that homogenization combined with UHT processing of milk caused not only changes in protein composition but also significant secondary structural loss, particularly in the amounts of apparent antiparallel β-sheet and α-helix, as well as diminished tertiary structural contact. In both cases of homogenization alone and followed by HTST treatments, neither caused appreciable chemical changes, nor remarkable secondary structural reduction. But disruption was evident in the tertiary structural environment of the whey proteins due to homogenization of whole milk as shown by both the near-UV circular dichroism and Trp intrinsic fluorescence. In-depth structural stability analyses revealed that even though processing of milk imposed little impairment on the secondary structural stability, the tertiary structural stability of whey protein was altered significantly. The following order was derived based on these studies: raw whole>HTST, homogenized, homogenized and pasteurized>skimmed and pasteurized, and skimmed UHT>homogenized UHT. The methodology demonstrated in this study can be used to gain insight into the behavior of milk proteins when processed and provides a new empirical and comparative approach for analyzing and assessing the effect of processing schemes on the nutrition and quality of milk and dairy product without the need for extended separation and purification, which can be both time-consuming and disruptive to protein structures.

show abstract