Microparticulated Whey Protein Research Articles

Effects of fat on the properties of halloumi cheese

Halloumi cheese was produced from 11 bovine milks with fat contents of 1.61–4.04%, giving a range of 32–53% fat in dry matter (FDM) in the cheeses. Starter culture and/or microparticulated whey protein (Simplesse ® 100(E)) was also added to selected batches of milk. Hardness decreased with increasing FDM, with increase in moisture and with lower pH. On sensory evaluation, there was an increase in preference score with FDM (R2 = 0.8). Inclusion of microparticulated whey protein may have had a fat mimetic effect, as preference scores otherwise decreased with increasing protein levels (R2 = 0.75).

SENSORY AND RHEOLOGICAL CHARACTERIZATION OF LOW‐FAT STIRRED YOGURT

ABSTRACT With the specific objective of investigating the sensory concept of creaminess, as well as other sensory attributes obtained from descriptive analysis, a set of 25 samples of stirred low‐fat yogurt were submitted to rheological (shear and imperfect squeeze flow viscometry, dynamic oscillation and Posthumus funnel) and sensory testing. Fat levels ranged from 0.3 to 3.5% and protein from 3.4 to 6.0%, and four different protein sources were employed, one being skimmed milk powder, the remaining three were milk protein preparations, one of which contained partially microparticulated whey protein (MPP). Based on averaged data from the sensory panel (n = 12), creaminess could be modeled by two other sensory descriptors, oral viscosity and smoothness (R2 = 0.78), but was poorly modeled by the entire set of rheological data. The MPP‐containing blend did best in terms of matching the creaminess scores of a control yogurt containing 3.5% fat (no additional protein added).

Flow and creep compliance properties of reduced-fat yoghurts containing protein-based fat replacers

The flow and creep compliance properties of reduced-fat yoghurts containing whey protein concentrate (WPC), microparticulated whey protein, or a blend of both fat replacers were determined and compared to those exhibited by a full-fat yoghurt (FFY). The flow behaviour of all the yoghurts was described by the Ellis equation. Rheological parameters such as instantaneous compliance (J0), mean compliance (Jm), mean retardation time (tm), and Newtonian viscosity (ZN) were useful to explain structural characteristics and changes in the protein network of the reduced-fat yoghurts. The yoghurt made with WPC showed flow and viscoelastic properties that resembled more closely those of the FFY. r 2004 Elsevier Ltd. All rights reserved.

Effect of fat replacers on the nutritive value and acceptability of beef frankfurters

This study determined the effect of fat replacers on the nutritive value and consumer acceptability of beef frankfurters. Four fat replacers, carrageen gum, modified cassava starch, microparticulated whey protein, and oat bran, were used to replace pork back fat (control). Use of whey protein resulted in a 71.7% decrease in total lipids, followed by oat bran, carrageen, and cassava starch with decrease of 70.6%, 70.0%, and 69.49%, respectively. The cholesterol and energy of frankfurters with carrageen were decreased by 32.0% and 29.0%, respectively. The panelists indicated that the formulation with cassava starch was similar to the control in terms of acceptability, thus suggesting that the lipid content was not the main deciding factor. Further work in this area is necessary to identify the ideal fat-replacer.

Microstructure and texture of yogurt as influenced by fat replacers

Abstract Seven reduced-fat yogurts were prepared from reconstituted milk (15 g fat L−1, 120 g total solids L−1) added with three commercial fat replacers consisting of whey protein concentrate (WPC), microparticulated whey protein (MWP) and modified tapioca starch (MTS), alone and combined. A reduced-fat yogurt (RFY, 15 g fat L−1 milk, 120 g total solids L−1) without added fat replacers and a full-fat yogurt (FFY, 30 g fat L−1 milk, 120 g total solids L−1) were elaborated as controls. Yogurts were stored 5 days at 4°C prior to instrumental texture profile analysis and microstructure analysis.

Heat-induced flocculation of microparticulated whey proteins (MWP); consequences for mixed gels made of MWP and β-lactoglobulin

Flocculation/aggregation processes occurred when suspensions of microparticulated whey proteins (MWP) were heated (or sheared). Large flocs were observed above both a critical volume fraction ( Φ MWP>0.099) and a critical temperature ( T>60 °C). These large structures combined at high volume fraction to form a coarse network which developed a liquid-like viscoelastic response. The rheological and structural consequences of such instabilities on mixed heat-set gels made of MWP and β-lactoglobulin (BLG) were studied. In particular, cooperative effects at low MWP volume fraction were observed. In addition, steric hindrance effects or thermodynamic incompatibility could occur between the two components at high MWP volume fraction leading to micro-phase separation in the mixed system. The theory of van der Poel failed to describe the experimental results. This was attributed to the strongly flocculated state of the MWP system and to the chemical affinity of MWP for the BLG network. These views were supported by diffusing wave spectroscopy measurements and confocal scanning laser microscopy observations.

FAT REPLACERS IN LOW‐FAT MEXICAN MANCHEGO CHEESE

Low‐fat Manchego cheeses (15 g fat/L milk) were prepared with three commercial fat replacers consisting of low methoxyl pectin (LMP), whey protein concentrate (WPC) and microparticulated whey protein (MWP). A low‐fat cheese (15 g fat/L milk) without added fat replacer and a full‐fat cheese (30 g fat/L milk) were prepared as controls. Cheeses were matured thirty days prior to instrumental texture profile analysis, microstructure analysis, and discriminative sensory evaluation. Scanning electron micrographs showed that the low‐fat cheeses incorporating the LMP and WPC fat replacers lost the compact and dense protein matrix characteristic of the low‐fat control cheese and exhibited hardness, springiness, cohesiveness and chewiness similar to the full‐fat control cheese. No significant difference was found in the sensory characteristics between the full‐fat control cheese and the cheese incorporating WPC.

Processed Cheese Analogues Incorporating Fat-Substitutes 1. Composition, Microbiological Quality and Flavour Changes During Storage at 5 °C

The effects on the perceived flavour of processed cheese analogue (spreadable type), of changes in the milk protein base, and of the substitution of milk fat by starch or microparticulate whey protein were studied. The gross chemical composition (g 100 g−1fat 12.3-22.8, protein 11.6-14.4 and carbohydrates 3.2-9.0) of the experimental samples was within the range typical of full- and low-fat commercial processed cheese spreads. Differences in sensory character were not associated with microbial contamination because coliforms were absent, and the counts of total viable count (TVC), yeast and moulds and of aerobic and anaerobic sporeforming bacteria were of no practical significance; for example, TVC=2.4×103cfu g−1). Products made using high protein skimmed milk powder were notably different in flavour and aftertaste from those made with retentate. Moreover, the analogues incorporating anhydrous milk fat were easily distinguished from those containing the other `lipid' types by their higher ratings for `creamy' and `buttery' flavour. Overall intensity of `flavour', `bitterness' and the `intensity' and `persistence' of aftertaste were influenced by storage period. These changes were associated with protein degradation during storage.

Processed Cheese Analogues Incorporating Fat-Substitutes 2. Rheology, Sensory Perception of Texture and Microstructure

The effects on the sensory perception of texture, rheology and microstructure of processed cheese analogue made with different milk protein bases, and substitution of milk fat by starch or microparticulate whey protein were studied. Differences in rheological properties of the products were influenced by (a) the duration of storage, (b) the cohesiveness character with respect to the lipid content, and (c) the compression response and spreadability characteristics with respect to lipid, storage period and/or base; the latter two aspects peaked at 2 months and then dropped to their initial values. Scanning and transmission electron microscopy revealed differences in the microstructure of processed cheese analogues. Products made with anhydrous milk fat contained higher concentrations of fat globules compared with analogues made with fat-substitutes. Electron-dense particles were evident in all the products, which could be undissolved protein aggregates or fat-substitutes, and no correlations could be found between such images and the rheological properties of processed cheese analogues. The porosity of the protein matrix was denser in processed cheese analogues made with high-protein skimmed milk powder.

Rheological properties of mixed gels made of microparticulated whey proteins and β-lactoglobulin

Microparticulated whey proteins (MWP) in suspension or included in a globular protein network revealed that the degree of flocculation was important in the final structure of the material. The MWP dispersions developed an antithixotropic character when low shear rate was applied to the system even at low temperature. Similar results were obtained on globular protein solutions and could be interpreted in terms of an orthokinetic aggregation. MWP participated to the formation and reinforcement of heat-induced β-lactoglobulin (BLG) gels. The mechanical properties of mixed gels demonstrated synergestic effects at low MWP massic fraction (BLG:MWP ratio higher than 2:1). A possible interpretation would be that both interaction of MWP with the network and flocculation of the MWP inside the pores could occur. However, increasing the fraction of MWP induced heterogeneities in the protein network. In particular, micro-phase separation due to steric hindrance effects or thermodynamic incompatibility between the two components could occur and decrease viscoelastic properties of mixed gels.

Effet de l'incorporation des protéines du lactosérum dénaturées et microparticulées dans le cheddar jeune

EtTect of incorporation of denatured and microparticulated whey protein in young Cheddar cheese. Two whey protein concentrates (WPC) heat-denatured at pH 4.2 (WPC 4.2) and at pH 6.7 (WPC 6.7) and microparticulated were used for the production of Cheddar cheese. Three micro-productions of Cheddar were made in triplicate: one with a control milk and the other two with milks in which the WPC 4.2 and WPC 6.7 ingredients were respectively added. The total amount of proteins was increased by 0.5 kgflOO kg of milk (0.5%). The expe- rimental cheeses had a significant higher yield, i.e., 4.3% with WPC 4.2 and 5.2% with WPC 6.7, than the control cheese, at a 37% constant moisture. Cheeses manufactured under these procedures were lower in fat and had a higher moisture content than the control chee se. Electronic micro- scopy shows that the control cheese had a more compact structure than the experimental cheeses. © InralElsevier, Paris. denaturation / whey protein / microfluidization / cheese yield

The effects of composition and some processing treatments on the rennet coagulation properties of milk

The effects of various processing parameters on the rennet coagulation properties of milk were assessed. Using low amplitude oscillation rheometry, the coagulation properties were monitored by measurement of the elastic shear modulus, G', as a function of time, t, from rennet addition; Gapos; was taken as a measure of curd firmness. The Scott‐Blair time dependency model was fitted to the experimental G' It curves for the determination of the following coagulation parameters: gel time, maximum curd firming rate, the set‐to‐cut time at 20 Pa (ie, time to reach 20 Pa) and the curd firmness after a renneting time of 2400 s. The renneting properties were enhanced by increasing the levels of milk protein and fat in the ranges 0.3–7.0% (w/w) and 0.1–10% (w/w) respectively and by two stage homogenization pressure where the first stage pressure, P1, was varied from 0 to 25 MPa and the second stage pressure, P2, was held constant at 5 MP a. The influence of these parameters, within the range investigated, in complementing the gel forming properties decreased in the following order: protein > fat > homogenization pressure. In contrast, the coagulation properties of milk were impaired by high heat treatment, the addition of a commercial microparticulated whey protein based fat substitute and by partial replacement of protein with fat.

Thermal Aggregation of Whey Protein Isolate Containing Microparticulated or Hydrolyzed Whey Proteins

Thermal aggregation from 25 to 97 °C (0.8 °C/min heating rate) of diluted whey protein isolate (WPI) containing microparticulated WPI (μWPI) or specific WPI tryptic hydrolysate was studied at pH 6.0 using a spectrophotometric method. Mixed WPI solutions containing above 3.75% μWPI displayed faster thermal aggregation at lower heating temperatures of protein species than the control WPI solutions (no μWPI added), with a shift of aggregation mechanism from predominantly homogeneous to biphasic. Interactions between whey proteins and soluble/insoluble whey protein microparticles were thought to be at the origin of the shift. Results also showed that the presence of 20-40% WPI tryptic hydrolysate into the WPI solutions improved whey protein thermal aggregation at pH 6.0. Such a result could not be ascribed only to protein-peptide interactions because hydrolysate promoted an initial acidification of WPI solutions from 6.9 to 5.4 (20% hydrolysate added) or to 4.6 (20% hydrolysate added), which contributed to whey protein isoelectric precipitation and formation of whey protein aggregates.

The microstructure of set‐style, natural yogurt made by substituting microparticulate whey protein for milk fat

The effect of a protein based fat substitute (Simplesse® 100) incorporated at a 1.5% level (w/w) in set‐style yogurt on its microstructure, syneresis and firmness was compared with the effect of anhydrous milk fat (AMF) used at the same concentration. The fat substitute was used in both commercial forms available, ie, as a dry or a wet ingredient. The yogurt bases consisted of reconstituted skimmed milk powder including the added ingredients and contained 14.3–15.5% total solids. Electron microscopy revealed that homogenization of AMF produced fat globules which interacted with milk proteins present in the yogurt base and thus the fat became an integral part of the yogurt microstructure. Similar integration was observed with the fat substitute, the particles of which (0.1–3 μm in diameter) were found to be parts of the casein micelle chains or spanned adjacent chains. These chains were found to be somewhat shorter (no statistical assessment was carried out) in the yogurts made with the fat substitute in wet or dry forms than in the yogurt made with AMF. Yogurts with the fat substitute were softer than the yogurts containing AMF, although their composition was similar except for the fat which was replaced with the fat substitute.

Microparticulation of whey protein: related factors affecting the solubility

Solubility of Simplesse 100, the only whey-based fat substitute, was found to be good, considering the fact that technology for preparation of Simplesse 100 is a sequence of thermal steps. To characterize this phenomen, gel chromatography on Sephadex G-100, Sephacryl S-1000 and SDS-PAGE were used, supported by high-speed separation, UV studies and analytical procedures. Results show that the unusual solubility characteristic of microparticulated whey protein is related to two molecular effects: (1) optimal defolding of protein molecules and (2) stabilization of the defolded status by carbohydrate. Both effects were considered to favour non-covalent bonds, which contribute to the outstanding physico-functional and nutritive properties of microparticles.

The effect of substitution of fat by microparticulate whey protein on the quality of set‐type, natural yogurt

Low calorie yogurts were manufactured from reconstituted skimmed milk powder using microparticulate whey protein (Simplesse 100® in wet and dry form) as a fat substitute. They were compared with yogurt containing anhydrous milk fat (AMF 1·5%). The quality of whey protein based yogurts (at a 1·5% level of addition) was high and similar to that of the control samples containing AMF. However, serum separation was higher and firmness was lower for yogurts containing microparticulate whey protein than for those containing AMF. This difference between yogurt containing AMF and microparticulate whey protein was most marked when microparticulate whey protein (ie, wet type) was incorporated on an equivalent dry matter basis to AMF. The sensory panel identified significant differences (p<0·05) between products containing AMF and microparticulate whey protein only in terms of sour odour and perceived serum separation.

The quality of microparticulated protein.

The purpose of this paper is to describe the effects of microparticulation upon the quality of microparticulated protein products and to confirm that microparticulation does not result in changes in protein structure or quality different from those that occur with cooking. Two products were tested: microparticulated egg white and skim milk proteins and microparticulated whey protein concentrate. Three approaches were used to monitor for changes in amino acid and protein value: amino acid analysis, protein efficiency ratio (PER) bioassay, and both one- and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. Evaluation of the results of these tests indicates that no significant differences were found when comparing the premix before and after microparticulation. Significant differences also did not occur when the premix was cooked using conventional methods. Collectively, the data provide strong evidence that the protein microparticulation process used to prepare microparticulated protein products (e.g., Simplesse) does not alter the quality or nutritional value of protein in the final products.