The Effect of Forewarming Heat Treatments on the Physical and Chemical Properties of Nonfat Dry Milk
Author: Jean Grindrod
Publisher:
Published: 1960
Total Pages: 110
ISBN-13:
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Author: Jean Grindrod
Publisher:
Published: 1960
Total Pages: 110
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DOWNLOAD EBOOKAuthor: Wayne Barry Sanderson
Publisher:
Published: 1965
Total Pages: 204
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DOWNLOAD EBOOKAuthor: John Henry Hetrick
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Published: 1947
Total Pages: 9
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DOWNLOAD EBOOKAuthor: J. J. Janzen
Publisher:
Published: 1952
Total Pages: 308
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DOWNLOAD EBOOKAuthor: Robert Arthur Larsen
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Published: 1949
Total Pages: 30
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DOWNLOAD EBOOKAuthor: Ronald Dean Marshall
Publisher:
Published: 1967
Total Pages: 220
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DOWNLOAD EBOOKAuthor: Clyde Howard Amundson
Publisher:
Published: 1960
Total Pages: 380
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DOWNLOAD EBOOKAuthor: Lu Wang
Publisher:
Published: 2016
Total Pages:
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DOWNLOAD EBOOKRadio frequency dielectric heating (RFDH) can provide rapid and uniform heating throughout the products' mass, and can be used to bake, dry, and defrost foods. Studies have shown that when RFDH induced a 5-log reduction of Salmonella spp. in nonfat dry milk (NDM), whey protein nitrogen index (WPNI) decreased, suggesting that functional properties of the NDM might be impacted. This research was conducted to determine if RFDH affected the functional properties of NDM [high-heat (HH) and low-heat (LH)]. Nonfat dry milk were treated to 75, 80 and 85°C in the RFDH unit, then were held for 125, 63 and 43 min for LH-NDM or 115, 52 and 43 min for HH-NDM, and cooled to ~23 ± 1°C. Powders were evaluated for WPNI, nitrogen solubility index, and color. Maillard browning and functional properties of NDM samples were evaluated after NDM was rehydrated to 3.5% protein with deionized water, and adjusted to pH 7.00. Glucono-delta-lactone was added in rehydrated NDM (3.5% protein; natural pH) as an acidifying agent to form milk gels, and the physical properties of the gels were determined. Two replications were conducted and data were analyzed with two-way ANOVA (RFDH and NDM) and Tukey mean differentiations (p d"0.05). Results showed that LH-NDM (collapsed for RFDH treatments) had 5.7% less viscosity, 20.9% less overrun, 27.4% less foam stability, as well as 15% less water holding capacity compared with HH-NDM (collapsed for RFDH treatments). This can be explained by the natural whey protein denaturation differences in the HH-NDM and LH-NDM. Viscosity and surface tension were impacted by the RFDH treatment. NDM (HH and LH) treated to 85°C had 10% greater viscosity than the control, and the NDM treated to 75°C had less surface tension compared with samples treated to 80°C, 85°C and the control. Overall, RFDH decreased WPNI in LH-NDM, but not HH-NDM. The SDS-PAGE gel images provided supportive evidence to the WPNI results. RFDH is a processing technology that could change a few functional properties of NDM in this study, which makes it a promising method that may be further exploited for various food applications, such as emulsifiers, foaming agents, etc. However, potential negative impacts, such as color change caused by Maillard reaction, loss of WPNI in LH-NDM, cannot be neglected.
Author:
Publisher:
Published: 2020
Total Pages: 172
ISBN-13: 9789463956185
DOWNLOAD EBOOKNot only lactoferrin is antibacterial, but a wider range of whey proteins its bacteriostatic activity, such as lactoperoxidase and immunoglobulins, as well as low abundant immune-active proteins. Different heat treatments can induce the denaturation of these proteins to a different degree, which could result in a gradual change of their bacteriostatic activity. The effect of different heat treatments on the proteome of whey proteins and their bacteriostatic activity were investigated in Chapter 4. Skim milk samples were heated at 65 °C, 70 °C, 75 °C, 80 °C, and 85 °C, for 30 minutes. Milk serum was isolated from the heat-treated skim milk and the bacteriostatic capacity of this milk serum was tested against Streptococcus thermophilus, Escherichia coli, Lactococcus lactis and Pseudomonas fluorescens. The bacteriostatic activity of milk serum negatively correlated with the intensity of heat treatment, which was also reflected in the reduced level of native antibacterial proteins. There is a slight decrease of bacteriostatic activity, which was associated with denaturation of low abundant immune-active proteins, such as complement C7, monocyte differentiation antigen CD 14 and polymeric immunoglobulin receptor. There is a significant difference between milk samples treated for 30 minutes at
Author: Lavell Gubler Wittwer
Publisher:
Published: 1960
Total Pages: 182
ISBN-13:
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