Record Details

Assessment of physico-chemical changes in UHT milk during storage at different temperatures.

KRISHI: Publication and Data Inventory Repository

View Archive Info
 
 
Field Value
 
Title Assessment of physico-chemical changes in UHT milk during storage at different temperatures.
Not Available
 
Creator Suvartan, R.; Sharma, R.; Gandhi, K. and Mann, B.
 
Subject NCN; NPN; particle size; UHT milk; zeta potential
 
Description Not Available
Ultra high temperature (UHT) processing is carried out at very high temperature for short
periods of time (135–150°C for 1–10 s), resulting in production of sterile milk which when
packaged aseptically is stable for about 6 months at room temperature. During storage of
UHT milk, various physio-chemical changes and enzymatic reactions take place including
dephosphorylation of casein micelles, breakdown of lactose, precipitation of calcium phos phate, disturbance of salt balance and proteolysis (Gaucher et al., 2008; Aldubhany et al.,
2014). These changes drastically affect the quality of UHT milk as a result of gelation,
which limits its shelf life and thus the consumer acceptance (Rauh et al., 2014).
Age-gelation is a major problem in UHT milk which is related to proteolysis by action of
native plasmin or psychotropic bacterial protease (Chavan et al., 2011). Many reasons have
been proposed to explain age-gelation such as acidification, Maillard reaction, enzymatic
and physico-chemical proteolysis (Gaucher et al., 2008; Chavan et al., 2011; Rauh et al.,
2014). The gelation of the product occurs in a two-stage mechanism. In the first stage, casein
micelles get dissociated from the complex formed between denatured β-lactoglobulin and
k-casein during heating of UHT milk. Second stage involves exclusively the physico-chemical
changes, which finally results in aggregation of casein micelles forming a 3D structure, causing
gelation (Gaucher et al., 2008; Chavan et al., 2011). However, Auldist et al. (1996) failed to
show any correlation between rate and extent of proteolysis with the onset of age-gelation, sup porting the importance of the second stage gelation mechanism. The exact mechanism of gel ation during storage of UHT milk is not yet clear and is still debatable. The objective of the
present study was to throw light on the mechanism of first stage reaction of proteolysis, the
aggregation of casein micelles and formation of a 3D structure. We investigated the suscepti bility of UHT milk to proteolysis during storage. Changes in size and zeta potential of casein
micelles, salt balance and nitrogenous compounds were also assessed which were correlated
with proteolysis in UHT processed milk during storage at room as well as refrigerated
temperature.
Not Available
 
Date 2021-08-26T08:36:56Z
2021-08-26T08:36:56Z
2020-04-21
 
Type Research Paper
 
Identifier Not Available
Not Available
http://krishi.icar.gov.in/jspui/handle/123456789/60787
 
Language English
 
Relation Not Available;
 
Publisher Not Available