Effects of heat treatment and homogenization on milk fat globules and proteins in whipping creams

doi:10.1016/j.foostr.2017.02.003

Food Structure

Volume 12, April 2017, Pages 94-102

https://doi.org/10.1016/j.foostr.2017.02.003 Get rights and content

Highlights

•
The quality of whipping creams varies with processing.
•
Stability against solidification and whippability should be controlled.
•
Colloidal properties of fat globules of the creams were studied.
•
The amount of proteins on fat globules should play an important role.
•
Second homogenization exerted a strong impact on the protein amount.

Abstract

The stability against solidification during storage and whippability of commercial cream products vary depending on the repetition of heat treatment and homogenization necessary for extended shelf-life. First, the two commercial creams subjected to different times of heat treatment and homogenization were investigated. Among several factors such as the colloidal properties, melting profiles of fat globules and protein content and composition, the amount of proteins present at the fat globule surfaces should play a major role in determining the cream quality probably in relation to the degree of expected partial coalescence of fat globules during transportation and whipping, while the composition of proteins adsorbed to the oil–water interface was not the critical factor affecting the quality of creams. A further step-wise preparation of cream samples in a laboratory scale revealed that the second homogenization significantly reduced the amount of proteins adsorbed to the surface of fat globules. There is a possibility that physical and colloidal macro-ordered properties of whipping creams can be controlled by appropriately managing the homogenization process.

Graphical abstract

Introduction

Cream is originally the concentrated fat globules that rise to the top of non-homogenized milk during the butter-making process and generally contain about 35% fat in the USA and UK (D’Amico, 1999, Davidson, 2014). It is nowadays produced throughout centrifugation process followed by heat treatment like UHT/HTST, homogenization, etc. to be used for food products such as coffee/tea, breads and cakes, often in the whipped state.

Cream is a naturally-derived oil-in-water emulsion where milk fat is dispersed in another immiscible liquid, water. An emulsion is often kinetically stable during a required term until consumption but thermodynamically unstable to undergo various types of destabilization including creaming, aggregation and coalescence (Dickinson, 1992). Among the destabilization phenomena, a kind of coalescence, partial coalescence particularly observed for emulsions produced and consumed at low-temperature like ice creams plays an important role for instability including solidification/thickening in liquid state during transportation/storage and for formation of the aerated unique structure of whipping creams during agitation (Mutoh, Nakagawa, & Noda, 2001; Rousseau, 2000).

Partial coalescence refers to the phenomenon generally occurring within a mechanical shear, in which fat crystals in one droplet induce instability of emulsions by penetrating the thin film between two approaching droplets and allowing liquid oils to flow out around the interactive site (Vanapalli and Coupland, 2004). Factors affecting partial coalescence are shear stress related to contact time and collision frequency, colloidal interactions, crystallization of fat globules and interfacial thickness related to membrane strength (McClements, 2004a). Goff (1997) pointed out that membrane composition of the fat globules seemed to be vital to partial coalescence and foam stability of the protein-based emulsions. Smith, Kakuda, and Goff (2000) emphasized the importance of proteins in the serum layer of whipped creams on the foam. There is an agreement based on lots of previous research that emulsions stabilized by caseins are more stable against partial coalescence than those by whey proteins (Fredrick, Walstra, & Dewettinck, 2010).

In Japan, since producing area and consuming area are not necessarily close to each other, manufacturers of dairy products are often required to carry out an additional heat treatment coupled with an additional homogenization on commercial creams already subjected to a heat treatment and homogenization in order to achieve extended shelf-life of the creams on the biological basis. On the other hand, such additional treatments are empirically known to result in substantial changes in emulsion stability and foaming properties of the creams according to manufacturers (Horiguchi et al., 2011). The creams manufactured through a single heat treatment and homogenization process are relatively unstable in the liquid state against solidification or thickening, easy to control whipped state and less off-flavored, whereas that through double processes is stable in a liquid state, difficult to control whipped state and more off-flavored (Horiguchi et al., 2011). However, mechanisms of the different characteristics between the two kinds of creams are unclear.

In the current study, in order to clarify the mechanisms of different characteristics of the creams to stability in the liquid state and different whippability, we used two commercial cream products subjected to single and double heating-homogenization processing to analyze colloidal properties and melting profiles of fat globules and proteins at the oil–water interface and in the bulk aqueous phase. As significant differences were found for the proteins particularly at the fat globule surfaces between the two commercial creams, we subsequently prepared more precisely controlled samples in a laboratory scale to elucidate which process of the treatments had a critical impact on the adsorbed proteins.

Section snippets

Materials

Two kinds of large-scale whipping cream commercial products subjected to single thermal treatment (T) in a UHT range (defined as 120–150 °C for <5 s) combined with high-pressure homogenization (H) or double one with the repeated processing, namely 1-TH or 2-TH creams were provided by Megmilk Snow Brand Co., Ltd. The commercial products were different in instability in the liquid state and whippability during agitation as described in the introduction part. Laboratory samples, i.e., small-scale

Large-scale commercial products

In order to examine the differences of colloidal properties between the two commercial creams, 1-TH and 2-TH creams, we performed particle size analysis, observation of microstructure and measurement of zeta-potential. Fig. 1 shows particle size distribution of 1-TH and 2-TH creams. The mean size of the fat globules in 1-TH and 2-TH creams was 2.59 ± 0.25 μm and 2.74 ± 0.18 μm, respectively. This difference was not statistically significant and the mono-modal distributions were almost the same;

Industrial relevance

This study is a highly industry-based work. It dealt with practical phenomena observed for real commercial cream products, while the mechanisms were studied with fundamental approachs. Based on the knowledge obtained from the study, there is a possibility that we can control physical and colloidal macro-ordered properties of whipping creams by appropriately managing the manufacturing process.

References (24)

E. Fredrick et al.
Factors governing partial coalescence in oil-in-water emulsions
Advances in Colloid and Interface Science
(2010)
O.H. Lowry et al.
Protein measurement with the Folin phenol reagent
Journal of Biological Chemistry
(1951)
M.C. Michalski et al.
Apparent ζ-potential as a tool to assess mechanical damages to the milk fat globule membrane
Colloids and Surfaces B: Biointerfaces
(2002)
T. Mutoh et al.
Effect of oil-soluble emulsifiers on solidification of thermally treated creams
International Dairy Journal
(2007)
J. Palanuwech et al.
Effect of surfactant type on the stability of oil-in-water emulsions to dispersed phase crystallization
Colloids and Surfaces A: Physicochemical and Engineering Aspects
(2003)
D. Rousseau
Fat crystals and emulsion stability – A review
Food Research International
(2000)
M.K. Rowney et al.
The effect of homogenization and milk fat fractions on the functionality of mozzarella cheese
Journal of Dairy Science
(2003)
A.K. Smith et al.
Changes in protein and fat structure in whipped cream caused by heat treatment and addition of stabilizer to the cream
Food Research International
(2000)
A.K. Smith et al.
Microstructure and rheological properties of whipped cream as affected by heat treatment and addition of stabilizer
International Dairy Journal
(2000)

A. Davidson

The oxford companion to food

E. Dickinson

An introduction to food colloids

(1992)

Cited by (10)

Static stability of partially crystalline emulsions: Impacts of carrageenan and its blends with xanthan gum and/or guar gum
2022, International Journal of Biological Macromolecules
Citation Excerpt :
Partially crystalline emulsions (PCEs), such as ice cream slurry, heavy creams, and whipping creams, are widely used in decorating coffee, tea, cakes, and desserts because of their capacity to form foam structures and delicious tastes [1,2].
In the present study, four different combinations of gums, including carrageenan (CG), its binary blends with xanthan gum (XG) or guar gum (GG) in equal ratios, and its ternary blends with XG and GG in three equal ratios, were involved into making partially crystalline emulsions (PCEs), respectively. The freshly prepared emulsions were systematically characterized by rheological property, particle size distribution, microscopic morphology, interfacial property, and intermolecular interactions, and their emulsion stabilities were further evaluated using multiple light scattering technique and storage test. All PCEs stabilized by gum blends (CG + XG, CG + GG, and CG + XG + GG) obtained decreased apparent viscosities at 0.01 s⁻¹ (10.12–25.32 Pa·s), particle sizes (3.12–4.06 μm), as well as interfacial protein concentrations (22.60–27.01 mg/m²), which were much lower than those with single CG (35.98 Pa·s, 6.72 μm, and 47.74 mg/m², respectively). The microscopic morphology showed that blending CG with XG and/or GG contributed to formation of firmer three-dimensional matrix, thereby preventing the aggregation of fat droplets. Inclusion of XG and/or GG also significantly reduced contribution of hydrophobic interactions from 0.72 to 0.24–0.44 mg/mL. Both multiple light scattering and storage test revealed that emulsion instabilities were mainly manifested as a clarification at the bottom and an agglomeration at the top. PCE-CG + XG + GG exhibited superior stability with low creaming index (6.20 %) and viscosity (1180.0 mPa·s) after three months of storage. The research aims to evaluate the effects of CG and its blends with XG and GG on stability of PCEs, and the results potentially provide valuable information for manufacture of stable PCE foods.
Effect of sucrose ester S370 on interfacial layers and fat crystals network of whipped cream
2021, Food Hydrocolloids
Citation Excerpt :
The droplets size of emulsion before whipping is a critical factor that influences fat crystallization and whipped cream. Small-size droplets would lead to higher supercooling nucleation and lower rate of fat coalescence (Matsumiya et al., 2017; Truong, Bansal, Sharma, Palmer, & Bhandari, 2014). The droplets size distribution of the emulsion at different S370 concentrations before whipping is shown in Fig. 1A.
The effect of sucrose ester S370 on the interfacial layers and fat crystals network of whipped cream has been studied in this work. The addition of S370 showed a little effect on the droplets size, interfacial protein concentration and viscosity of emulsion samples before whipping. However, the addition of S370, as a heterogeneous nucleating agent, could induce nucleation and lead to the formation of more small crystals in the bulk mixture and emulsions. These small crystals, which were not able to pierce the interface of fat droplets effectively, would retard fat coalescence during whipping process. The addition of S370 resulted in lower degree of fat coalescence, lower interfacial protein concentration, shorter optimum whipping time (t_op) and lower overrun of whipped cream. At lower S370 concentration (<0.05 wt%), large-size crystals and inhomogeneous fat crystals network led to lower firmness and less bubbles stability of whipped cream samples. At 0.05 wt% S370 concentration, homogeneous crystals network, resulted in whipped cream with high firmness and bubbles stability. However, lower interfacial protein concentration and small-size crystals were observed at higher concentration of S370 (>0.05 wt%). As a result, the aerated structure was not strong enough to stabilize whipped cream.
Effects of pressure, shear, temperature, and their interactions on selected milk quality attributes
2021, Journal of Dairy Science
Citation Excerpt :
Samples were diluted with ultra-pure water in the ratio of 1:1,000. Milk fat particle refractive index of 1.45–0.01i and dispersant refractive index of 1.33 were used (Matsumiya et al., 2017). Particle size was measured within 1 h after treatments.
The effects of pressure, temperature, shear, and their interactions on selected quality attributes and stability of milk during ultra-shear technology (UST) were investigated. The UST experiments include pressure (400 MPa) treatment of the milk sample preconditioned at 2 different initial temperatures (25°C and 15°C) and subsequently depressurizing it via a shear valve at 2 flow rates (low: 0.15–0.36 g/s; high: 1.11–1.22 g/s). Raw milk, high-pressure processed (HPP; 400 MPa, ~40°C for 0 and 3 min) and thermal treated (72°C for 15 s) milk samples served as the controls. The effect of different process parameters on milk quality attributes were evaluated using particle size, zeta potential, viscosity, pH, creaming, lipase activity, and protein profile. The HPP treatment did not cause apparent particle size reduction but increased the sample viscosity up to 3.08 mPa·s compared with 2.68 mPa·s for raw milk. Moreover, it produced varied effects on creaming and lipase activity depending on hold time. Thermal treatment induced slight reduction in particle size and creaming as compared with raw milk. The UST treatment at 35°C reduced the effective diameter of sample particles from 3,511.76 nm (raw milk) to 291.45 nm. This treatment also showed minimum relative lipase activity (29.93%) and kept milk stable by preventing creaming. The differential effects of pressure, shear, temperature, and their interactions were evident, which would be useful information for equipment developers and food processors interested in developing improved food processes for dairy beverages.
Proteomics analysis of milk fat globule membrane enriched materials derived from by-products during different stages of milk-fat processing
2019, LWT
Citation Excerpt :
The MFGM protein compositions in five groups of MFGM enriched materials, isolated from by-products during different stages of milk-fat processing, was clearly characterized by LC-MS/MS. Distinct from pure MFGM, the MFGM materials in our study were enriched in MFGM protein and MFGM lipid, and also included a certain amount of casein and whey protein. The result was consistent with that previously reported in MFGM isolates (Matsumiya et al., 2017; Phan, Le, Van Der Meeren, & Dewettinck, 2014). The relative abundance of several major MFGM proteins in five samples were exhibited in Fig. 4.
By-products produced during milk-fat processing contain abundant milk fat globule membrane (MFGM) and are usually considered as sources of MFGM proteins. However, the technological conditions during cream processing affect the composition/profile of the MFGM proteins and change the functional properties of MFGM proteins. In this paper, the simulative process of industrial manufacture of cream, butter and anhydrous milk fat was done in the lab, five kinds of by-products were collected from different stages (different technical treatments or different fat content) to isolate MFGM enriched material. Proteomics analysis of MFGM enriched materials was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). 357, 429, 323, 578 and 332 proteins were identified in five groups of by-products. Several major MFGM proteins were detected in all samples with the high relative abundance. Samples obtained after phase inversion showed higher protein number and higher concentration of major MFGM proteins compared with centrifuged skimmed milk. Both the number and the concentration in samples collected after phase inversion increased with fat content of cream. GO analysis revealed GTPase activity was the specific molecular function of MFGM proteins in butter serum (BS-1). The MFGM protein profiles also provided novel insights into the individual MFGM product which was rich in certain membrane proteins. Butter serum was the best source for isolating complete MFGM proteins product. This work will facilitate the development of deep processing market for dairy by-products, and provide theoretical reference for the production of MFGM protein products.
Hazards of a ‘healthy’ trend? An appraisal of the risks of raw milk consumption and the potential of novel treatment technologies to serve as alternatives to pasteurization
2018, Trends in Food Science and Technology
Citation Excerpt :
High-pressure homogenizers, which are a development upon the valve needle and seat Gaulin-type model are in common use nowadays, operating in the pressure range of 15–30 MPa. Machines that can operate at higher pressure values, have been developed and their process is termed high pressure homogenizing, a concept described in richer detail in section 8.2 below (Diels, Wuytack, & Michiels, 2003; Matsumiya et al., 2017). Homogenization will not satisfactorily inactivate enteric pathogens, and so heat treatments are necessary to ensure the microbiological safety and preservation of milk and milk products.
Milk is a nutritious and healthy dietary component of many adults and infants, all over the world. For numerous reasons, the consumption of raw, unpasteurized milk is a growing trend. This practice may, however, be risky as raw milk consumption has potentially severe health consequences.
In the midst of the fierce debate and controversy, it is important to find support in rigorous scientific evidence. In this review, the contemporary epidemiological significance of raw milk, as well as the scientific basis and justification for milk pasteurization, are presented. The hazards associated with raw milk consumption, the primary sources and routes of microbial contaminants into milk, as well as factors that may predispose milk to microbial contamination, are explored. Relevant livestock commensal microbiota and diseases, environmental sources and pathways, as well as post-pasteurization contamination are considered. Some of the motivating factors driving raw milk consumption and the purported benefits of drinking unpasteurized milk are examined. Furthermore, the main scientifically verified differences between pasteurized and unpasteurized milk are discussed, and attempts are made to refute some of the biased claims regarding the human health benefits of raw milk. Given that many raw milk enthusiasts are skeptical of pasteurization, we explore the potential of some novel treatment techniques that could serve as alternatives to pasteurization.
Scientific evidence shows that pasteurization is so far, the primary, incontrovertible safeguard for milk and it only slightly alters the nutritive and organoleptic profile of milk. There are a number of novel technologies, which seem to be milder and if properly optimized in the near future may serve as suitable alternatives to pasteurization. It is anticipated that these technologies or a reasonable combination of key processes, will enable the production of milk and milk products that are microbiologically safe, yet publicly accepted.
Effects of Second-stage Homogenization Pressure on the Quality of Butter-based Whipped Cream
2023, Modern Food Science and Technology

View all citing articles on Scopus

View full text

Effects of heat treatment and homogenization on milk fat globules and proteins in whipping creams

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Large-scale commercial products

Industrial relevance

Advances in Colloid and Interface Science

Journal of Biological Chemistry

Colloids and Surfaces B: Biointerfaces

International Dairy Journal

Colloids and Surfaces A: Physicochemical and Engineering Aspects

Food Research International

Journal of Dairy Science

Food Research International

International Dairy Journal

The oxford companion to food

An introduction to food colloids