FIELD OF THE INVENTION

The invention relates to a shelf stable ready-to-drink (RTD) beverage product comprising aggregated proteins comprising micellar casein and whey protein aggregates. The present invention also relates to a method for forming agglomerated proteins in a beverage.

BACKGROUND

It is known to provide texture and mouthfeel to food and beverage product by protein aggregation. There continues to be a need for food and beverages products exhibiting nutritional balance of macronutrients while delivering great taste and texture.

CN104489097A describes a process to obtain a heat convection drying protectant preparations for lactic bacteria or probiotics consisting in heat treating at 60° C. a milk preparation enriched with calcium in order to induce protein aggregation and subsequently submitting the preparation to a mechanical homogenization treatment. This patent application does not relates to beverage preparation.

WO 06065135 A2 disclosing the production of a free divalent cations-rich liquid food product in which 20% of the lysine residues carried out by the proteins have been glycosylated in order to increase their resistance to aggregation in presence of calcium. Therefore, WO 06065135 A2 is related to preventing protein aggregation in presence of divalent cations, calcium among others.

US20130011515 A1 is describing a process for the production of a milk protein concentrate which is enriched with whey proteins. Skimmed milk is heated in the pH range 6.5-7.0 in order to promote aggregation of whey proteins together with caseins. The heated product is subsequently submitted to filtration in order to concentrate protein aggregates and to remove lactose. US20130011515 A1 is not concerned with the preparation of shelf stable beverages.

D. L. Van Hekken et al. [Rheology and Microstructure of Chemically Superphosphorylated Whole Casein, 1997, J. Dairy Sci. 80 2740-2750.] described the effect of addition of free calcium on the viscosity of superphosphorylated caseins. It was shown that the viscosity of a 4 wt. % superphosporylated caseins (190% phosphorylation) increased by addition of 30 mM calcium at pH 8.4. This study does not cover beverage products. Further, for beverage products the superphosporylated caseins are not desirable relevant as chemically modified and expensive ingredient.

C. Holt described in his paper [An equilibrium thermodynamic model of the sequestration of calcium phosphate by casein micelles and its application to the calculation of the partition of salts in milk, 2004, Eur. J. Phys., 33, 421-434] reported that the amount of free calcium ions in bovine milk at pH 6.70 was 10.2 mM and that this value decreased to 8 mM when milk pH decreased to 6.0. This study does not describe protein aggregation resulting from interaction with free calcium ions.

I. R. McKinnon et al. [Diffusing-wave spectroscopy investigation of heated reconstituted skim milks containing calcium chloride, 2009, Food Hydrocolloids, 1127-1133] investigated the effect of calcium chloride addition to skimmed milk reconstituted at 10 wt. % in the pH range 6.0-7.2 and the subsequent effect on viscosity when the milks were heated for 10 minutes at 60, 75 and 90° C. They reported a critical instability pH of 5.9 for the milks upon heating at 90° C. for calcium chloride content up to 10 mM. The article by I. R. McKinnon is silent about how to make beverage products with a good shelf-life stability.

L. Ramasubramanian et al. [The rheological properties of calcium-induced milk gels, 2014, J. Food Engineering, 45-51] determined the impact of calcium chloride addition into full fat milk (3.5% fat) upon heating at 70° C. It was reported that calcium chloride addition below 12.5 mM was leading to viscous dispersions while higher calcium chloride concentrations induced formation of stronger gels. Interestingly, pre-treatment of the milk at 90° C. for 10 minutes before calcium chloride addition and subsequent heating at 70° C. was leading to the strongest gels. Gel formation is not desirable in shelf stable beverages.

T. Phan-Xuan et al. [Tuning the structure of protein particles and gels with calcium or sodium ions. 2013, Biomacromolecules, 14, 6, 1980-1989.] reported that addition of calcium chloride to β-lactoglobulin at pH 7.0 was leading to microgels or gel formation upon heating at 68 or 85° C. when calcium content was 5-6 mM for a protein concentration of 4 wt. %. Gel formation is not desirable in shelf stable beverages.

The prior art teaching shows that although viscosity may be obtained with calcium addition and gelling is a well know effect but this is undesirable in beverage production. Furthermore, the pH of the product is close to neutral and influence of divalent ions and heat treatment process may lead to instability of the RTD beverage product during shelf life. The prior art does not show how to provide RTD beverage products delivering desirable taste and texture while maintaining good physical stability during product shelf-life.

For RTD products stability is critical during shelf life especially for storage at ambient temperatures. For example it is important to avoid serum, marbling, sedimentation or gelation.

Thus, there is a need for beverage products which are low in fat while having same or improved mouthfeel and texture while delivering good physico-chemical stability during product shelf-life.

OBJECT OF THE INVENTION

It is thus the object of present invention to provide a ready-to-drink beverage with improved texture and mouthfeel.

SUMMARY OF THE INVENTION

The present invention provides the improvement by the use of milk protein-based aggregates by specific heat treatment in the presence of a specific concentration of added divalent cations.

In a first aspect, the invention relates to a method of producing a shelf stable ready-to-drink beverage product, comprising the steps of:providing an ingredient composition comprising micellar caseins and whey protein, having a total protein concentration of 1.5-8 wt. %, and wherein the composition has a casein to whey protein ratio of 90/10-60/40,adding divalent cations to provide a concentration of 3-20 mM free divalent cations in the ingredient composition, and 0.025-0.3 wt % of a stabilizing system comprising hydrocolloids, and subsequentlyheat treating the ingredient composition at ultra high temperature (UHT) at 135 150° C. for 3 30 s to form agglomerated proteins comprising casein and betalactoglobulin from the whey protein, the agglomerates having a size of 5-30 microns mean diameter D(4,3)as measured by laser diffraction.

The present invention uses milk protein-based aggregates that are generated upon heat treatment in presence of added-free divalent cations in combination of hydrocolloids to deliver optimum sensorial properties while allowing a reduction of the total fat and/or sugar content in the product, as well as good physical chemical stability during product shelf-life. In addition, the described invention enables formulation of dairy-based texturized products which are shelf stable with stabilizing system comprising specific range of hydrocolloids. Content of hydrocolloids below this range may lead to sedimentation and/or serum separation. Addition of hydrocolloids above this range might result in gelation.

In a second aspect the invention relates to shelf stable ready-to-drink beverage product comprising aggregated proteins comprising micellar caseins and whey protein aggregates, wherein the product has a pH of 6.6-7.2, 1.5-8.0 wt. % milk proteins, a casein to whey protein ratio of 90/10-60/40, and a concentration of 3-20 mM divalent cations, and the aggregates are of 5 30 microns mean diameter D(4,3)as measured by laser diffraction.

