Flavor Release of the Tomato Flavor Enhancer, 2-Isobutylthiazole, from Whey Protein Stabilized Model Dressings

2011 ◽  
Vol 17 (2) ◽  
pp. 143-154 ◽  
Author(s):  
K.F. Christiansen ◽  
E. Olsen ◽  
G. Vegarud ◽  
T. Langsrud ◽  
P. Lea ◽  
...  
Keyword(s):  
Whey Protein ◽  
Complex Modulus ◽  
Headspace Analysis ◽  
Temperature Treatment ◽  
Whey Protein Concentrate ◽  
High Temperature Treatment ◽  
Flavor Release ◽  
Tomato Flavor ◽  
Β Lactoglobulin ◽  
Flavor Enhancer

A tomato flavor enhancer, 2-isobutylthiazole (IBT), was added (5 mg/kg) to dressings emulsified with either a whey protein concentrate-80 (WPC-80), a WPC-80 hydrolysate or β-lactoglobulin at high pressure (70 MPa) at either 20 or 75 °C. The short (2-4 min), high-temperature treatment left the proteins essentially unchanged. IBT addition gave a dominant, green tomato flavor that masked the intrinsic odor of the WPC-80 hydrolysate but enhanced bitter flavor. The sensory IBT odor intensity was determined by oil level (5-30%) and pH; pH 4.0 gave higher IBT odor than pH 6.5. The green (IBT) odor release correlated with the sensory viscosity (p = 0.001) and with instrumentally determined complex modulus (p = 0.001), but not to the dressings’ microstructure. The presence of small (<<1.5 µm) oil particles that were difficult to identify from images may explain why no correlation between green odor and microstructure was found. Headspace analysis significantly detected differences in the release of IBT from the different protein types: WPC-80 dressings released the most and β-lactoglobulin the least amounts of IBT into headspace. As this difference in release of IBT among proteins could not be verified by sensory analysis, it may bear no relevance for perception.

Comparison of heat and pressure treatments of skim milk, fortified with whey protein concentrate, for set yogurt preparation: effects on milk proteins and gel structure

2000 ◽  
Vol 67 (3) ◽  
pp. 329-348 ◽  
Author(s):  
ERIC C. NEEDS ◽  
MARTA CAPELLAS ◽  
A. PATRICIA BLAND ◽  
PRETIMA MANOJ ◽  
DOUGLAS MACDOUGAL ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Whey Protein ◽  
Skim Milk ◽  
Milk Proteins ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Casein Micelles ◽  
Micelle Structure ◽  
Dynamic Structures ◽  
Β Lactoglobulin

Heat (85 °C for 20 min) and pressure (600 MPa for 15 min) treatments were applied to skim milk fortified by addition of whey protein concentrate. Both treatments caused > 90% denaturation of β-lactoglobulin. During heat treatment this denaturation took place in the presence of intact casein micelles; during pressure treatment it occurred while the micelles were in a highly dissociated state. As a result micelle structure and the distribution of β-lactoglobulin were different in the two milks. Electron microscopy and immunolabelling techniques were used to examine the milks after processing and during their transition to yogurt gels. The disruption of micelles by high pressure caused a significant change in the appearance of the milk which was quantified by measurement of the colour values L*, a* and b*. Heat treatment also affected these characteristics. Casein micelles are dynamic structures, influenced by changes to their environment. This was clearly demonstrated by the transition from the clusters of small irregularly shaped micelle fragments present in cold pressure-treated milk to round, separate and compact micelles formed on warming the milk to 43 °C. The effect of this transition was observed as significant changes in the colour indicators. During yogurt gel formation, further changes in micelle structure, occurring in both pressure and heat-treated samples, resulted in a convergence of colour values. However, the microstructure of the gels and their rheological properties were very different. Pressure-treated milk yogurt had a much higher storage modulus but yielded more readily to large deformation than the heated milk yogurt. These changes in micelle structure during processing and yogurt preparation are discussed in terms of a recently published micelle model.

scholarly journals Characterization of heat-induced aggregates of β-lactoglobulin, α-lactalbumin and bovine serum albumin in a whey protein concentrate environment

2001 ◽  
Vol 68 (3) ◽  
pp. 483-497 ◽  
Author(s):  
PALATASA HAVEA ◽  
HARJINDER SINGH ◽  
LAWRENCE K. CREAMER
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Whey Protein ◽  
Bovine Serum ◽  
Concentrate Solution ◽  
Polyacrylamide Gel Electrophoresis ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Two Dimensional ◽  
Β Lactoglobulin

Bovine β-lactoglobulin (β-lg), α-lactalbumin (α-la) and bovine serum albumin (BSA), dispersed in ultrafiltration permeate, that had been prepared from whey protein concentrate solution (100 g/kg, pH 6·8), were heated at 75 °C. The consequent protein aggregation was studied by one-dimensional (1D) and two-dimensional (2D) polyacrylamide gel electrophoresis (PAGE). When 100 g β-lg/kg permeate solution was heated at 75 °C, cooled and examined, large aggregates were observed. These aggregates were partially dissociated in SDS solution to give monomers, disulphide-bonded dimers, trimers and larger aggregates. When mixtures of β-lg and α-la or BSA were heated, homopolymers of each protein as well as heteropolymers of these proteins were observed. These polymer species were also observed in a heated mixture of the three proteins. Two-dimensional PAGE of mixtures demonstrated that these polymers species contained disulphide-bonded dimers of β-lg, α-la and BSA, and 1:1 disulphide-bonded adducts of α-la and β-lg, or BSA. These results are consistent with a mechanism in which the free thiols of heat-treated β-lg or BSA catalyse the formation of a range of monomers, dimers and higher polymers of α-la. It is likely that when whey protein concentrate is heated under the present conditions, BSA forms disulphide-bonded strands ahead of β-lg and that α-la aggregation with β-lg and with itself is catalysed by the heat-induced unfolded BSA and β-lg.

Heat-related changes to the hydrophobicity of cheese whey correlate with levels of native β-lactoglobulin and α-lactalbumin

1992 ◽  
Vol 59 (4) ◽  
pp. 527-532 ◽  
Author(s):  
Geoffrey O. Regester ◽  
R. John Pearce ◽  
Victor W. K. Lee ◽  
Michael E. Mangino
Keyword(s):  
Cheese Whey ◽  
Binding Capacity ◽  
Whey Proteins ◽  
Surface Hydrophobicity ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Native Proteins ◽  
Native Whey ◽  
Induced Changes ◽  
Β Lactoglobulin

SummaryCorrelations were identified between levels of the native whey proteins, β-lactoglobulin and α-lactalbumin and the surface and total hydrophobicities of cheese whey in response to different heat treatments. Heat-induced changes in the native βlactoglobulin content and surface hydrophobicity of whey exhibited the most significant linear relationship while correlations between total hydrophobicity and the native proteins were less significant because of an atypical rise in the n−heptane-binding capacity of whey after high-temperature treatment. The content of native β-lactoglobulin in whey was more sensitive to heating than the content of native α-lactalbumin, while heat-related changes in the total hydrophobicity of whey were generally greater than similar changes in surface hydrophobicity.

scholarly journals Mildly Pasteurized Whey Protein Promotes Gut Tolerance in Immature Piglets Compared with Extensively Heated Whey Protein

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3391
Author(s):  
Marit Navis ◽  
Lauriane Schwebel ◽  
Susanne Soendergaard Kappel ◽  
Vanesa Muncan ◽  
Per Torp Sangild ◽  
...  
Keyword(s):  
Human Milk ◽  
Whey Protein ◽  
Transit Time ◽  
Protein Composition ◽  
In Vitro Digestion ◽  
Whey Protein Concentrate ◽  
Milk Formula ◽  
The Impact ◽  
Β Lactoglobulin

Human milk is the optimal diet for infant development, but infant milk formula (IMF) must be available as an alternative. To develop high-quality IMF, bovine milk processing is required to ensure microbial safety and to obtain a protein composition that mimics human milk. However, processing can impact the quality of milk proteins, which can influence gastro-intestinal (GI) tolerance by changing digestion, transit time and/or absorption. The aim of this study was to evaluate the impact of structural changes of proteins due to thermal processing on gastro-intestinal tolerance in the immature GI tract. Preterm and near-term piglets received enteral nutrition based on whey protein concentrate (WPC) either mildly pasteurized (MP-WPC) or extensively heated (EH-WPC). Clinical symptoms, transit time and gastric residuals were evaluated. In addition, protein coagulation and protein composition of coagulates formed during in vitro digestion were analyzed in more detail. Characterization of MP-WPC and EH-WPC revealed that mild pasteurization maintained protein nativity and reduced aggregation of β-lactoglobulin and α-lactalbumin, relative to EH-WPC. Mild pasteurization reduced the formation of coagulates during digestion, resulting in reduced gastric residual volume and increased intestinal tract content. In addition, preterm piglets receiving MP-WPC showed reduced mucosal bacterial adherence in the proximal small intestine. Finally, in vitro digestion studies revealed less protein coagulation and lower levels of β-lactoglobulin and α-lactalbumin in the coagulates of MP-WPC compared with EH-WPC. In conclusion, minimal heat treatment of WPC compared with extensive heating promoted GI tolerance in immature piglets, implying that minimal heated WPC could improve the GI tolerance of milk formulas in infants.

Sign in / Sign up

Export Citation Format

Share Document