FIELD OF THE INVENTION

The present invention relates to an aqueous composition comprising oat material such as an oat drink capable of forming a vegetable foam of improved stability on whipping, to a method for its production, and to a foam so prepared.

BACKGROUND OF THE INVENTION

Vegetable drink manufacture from starchy starting materials such as oats involves the use of starch degrading enzymes in combination with an aqueous suspension of milled starchy material, in particular oats, at a temperature that allows the gelatinization of starch. The extraction of functional substances from the kernel, such as oat proteins and beta-glucan, is limited by their entrapment in networks of plant cell walls.

At the pH of popular foods and drinks the solubility of plant proteins in water is often very low, which compromises their functionality. Low protein solubility is often accompanied by an undesirable gritty and sandy mouthfeel. There have been attempts to circumvent this problem chemically or enzymatically by modifying or eliminating portions of the protein molecule, in particular by succinylation or deamidation.

Succinylated proteins have increased solubility above the isoelectric point, cf. WO 202011/7927 A1.

Deamidation by protein-glutamine glutaminase releases ammonia and creates hydrophilic glutamate groups thus enhancing the solubility of oat protein, cf. WO 2014/12346 and WO 2020150583 A1.

Pulsed electric field is an established non-thermal method of processing foods by means of short high voltage pulses inducing disintegration of vegetable cells, cf., L. Buchmann, A. Mathys, 2019, Perspective on Pulsed Electric Field Treatment in the Bio-based Industry, Front. Bioeng. Biotechnl. (https://www.frQntiersin.org/artictes/10.3389/fbioe .2019.00265/full), AU 2012/100749 A4, www.opticept.se.

Pulsed electric field (PEF) can be used for the preservation and sterilization of food. The pulsed electric field induces the formation of a potential difference across a conductive biological material such as cell membranes between two electrodes, creating an electric field depending on the applied voltage. PEF can induce an electric potential across a cell membrane causing an electrostatic charge separation in the cell membrane based on the polar nature of cell membrane molecules. When the electric potential over the cell membrane exceeds a critical value, pores form in the cell membrane and at a certain electric potential cell membrane damage is so extensive that cells are inactivated and succumb. PEF therefore leads to enhanced mass, material and heat transfers as well as the total inactivation of the cells or cell lysis.

Protease and peptidase are known to be useful in hydrolytically solubilizing plant protein. Excessive protein hydrolysis does however result in a bitter taste and browning, thus deteriorating the nutritional quality of the drink. Moreover, in this context, proteolysis rather degrades protein already suspended in the aqueous medium instead of solubilizing protein comprised by the plant m aterial . (https://biosolutions .novozy rnes. protein/products/oat- drinks/formea-soboats and https://biosolutions.novozymes.com/en/plant- protein/products/neutrase-oats)

Soy protein has rather unique solubility features, which explain the broad use of this legume in various food applications. Soy is however a known allergen. For this reason, products comprising soy protein are avoided by many consumers. Most plant proteins of nutritional value other than soya protein exhibit poor solubility, which hampers their use in liquid food preparations such as non-dairy drinks.

Addition of protein concentrates or isolates, such as those originating from yellow peas or chickpeas, to a vegetable drink for increasing its content of soluble protein may affect its taste in a negative manner while only providing minor improvement of functionality.

The use of vegetable drinks for coffee beverages such as a coffee latte, produced by blending espresso coffee and steamed vegetable drink (instead of dairy milk) is becoming increasingly popular, cf. WO 2004/43157 A1 and WO 2014/123466 A1. Protein, in particularly casein, is essential for enabling a homogenous, smooth and stable foam to be formed on whipping, cf. Xiong et al, 2020 Foaming properties of milk protein dispersions at different protein content and casein to whey protein ratios', International Dairy Journal, vol. 109, oct 2020.

(https://www.sciencedirect.com/science/article/abs/pii/S0 95869462030128X).

Soy drink is preferentially used as dairy drink due to its milky color and its good foaming properties in combination with good foam stability. Its use is though hampered by its allergenic properties. To avoid the drawbacks of soy protein many vegetable drinks in the market, such as Barista-type products, use other vegetable proteins in spite of their limited foaming ability (frothability), which often needs to be improved by addition of proteins, emulsifiers and/or stabilizers, such as pea protein, lecithin, guar gum, and gellan gum.

See, for instance: https://joya.info/en/products/dream-and-joya-almond-drink-ba rista- 2100. Composition: water, almonds 2,5% by weight, 5 maltodextrin, stabilizers, gellan gum and lecithin; acidity regulator dipotassium phosphate; sodium chloride. https://joya.info/en/products/dream-and-joya-soya-drink-bari sta-1891 . Composition: soya base 99% (water, soya beans 7,5%), calcium carbonate, stabiliser gellan gum; acidity regulator potassium carbonate; vitamin D, natural flavouring, sodium chloride.

All references such as patent documents, scientific publications and information available through the hyperlinks are all incorporated herein by reference.

OBJECTS OF THE INVENTION

An object of the invention is to provide an oat drink of improved foaming properties, in particular of the volume of foam produced by foaming.

Another object of the invention is to provide a foamed oat drink the foam of which has improved stability.

A further object of the invention is to provide a foamed oat drink of improved taste.

A further objective is to increase and/or improve the foam density. A further objective is to increase the foam density and the maintenance of an increased and/or improved foam density over time.

Additional objects of the invention will become evident from the following description of the invention.

SUMMARY OF THE INVENTION

The present invention relates to a method for the provision of an aqueous composition comprising oat material, the oat material comprising starch and betaglucan, the method comprising providing dehulled and heat-treated oat material; mixing the oat material with water at a weight ratio of from about 1 :7 to about 1 :11 thereby providing an aqueous composition comprising oat material, and in any order: applying a pulsed electric field (PEF) on the aqueous composition comprising oat material ; adding hydrolytic enzyme to the aqueous composition comprising oat material; keeping the PEF-treated aqueous composition comprising oat material and hydrolytic enzyme at a temperature of from about 40°C to about 85°C for a time period sufficient for hydrolysis of starch and beta-glucan fiber.

The power of the pulsed electric field is preferably at least about 1 kW, preferably at least about 1 ,3 kW or at least about 1 ,5 kW, at an average flow rate of about 0.16 m ³ /h.

It is preferred for the temperature for hydrolysis of starch and beta-glucan fiber to be from about 50°C to about 75°C, in particular from about 55°C to about 70°C, most preferred of about 60°C up to about 65°C.

It is furthermore preferred that mixing is by stirring and admixture is being maintained by continued stirring.

According to another embodiment of the invention the hydrolytic enzyme selected from starch degrading enzymes. Preferred starch degrading enzymes are alphaamylase and beta-amylase.

In the method of the invention, a time period sufficient for hydrolysis of starch and beta-glucan fiber is half an hour or more, in particular one hour or more. Also disclosed herein is a composition of oat material such as an oat drink prepared by the method of the invention. An emulsion for preparing a foamed oat drink of the invention comprises or consists of the composition of oat material such as an oat drink of the invention and vegetable oil. By whipping it in an atmosphere of air or nitrogen the emulsion can be transformed to a foamed oat drink consisting of an aqueous drink phase and of foam, in particular of foam comprising 60 % or more of the total volume, in particular 65 % or more, most preferred 75 % or more, such as about 80 % or more.

Also disclosed herein is a foamed oat drink prepared by the method of the invention.

In a method of producing a vegetable foam of the invention, foam comprised by a foamed oat drink of the invention is separated from the aqueous phase.

A modified vegetable foam of the invention is produced by admixing the vegetable foam of the invention with one or more of sweetener, colorant and flavoring agent.

Herein the terms ‘froth’ and ‘foam’ are used. In the field of oat drinks these terms are to an extent used interchangeably although a froth may signify a foam with a high density, i.e. a high-density foam translating into to a foam with a high number of bubbles per volume element. As used herein the term foam encompasses any type of foam such as high-density foam and froth.

SHORT DESCRIPTION OF FIGURES

Fig. 1 Improved frothability of oat drink by added rapeseed oil (1 ,5 % by weight)

Fig. 2 Improved storage stability of a PEF-treated oat drink

Fig. 3 Density of the froth measured 10 minutes after the frothing protocol as a function of storage period of the emulsion. Graphical representation of table 1 .

Fig. 4 Percentage of foam left after 10 minutes as function of storage time. Graphical representation of table 2.

SUBSTITUTE SHEET (Rule 26) FURTHER EMBODIMENTS OF THE INVENTION

As presented the method comprises subjecting a composition of oat material to a pulsed electric field (PEF) and starch degrading enzymes. The addition of starch degrading enzymes can be performed either before PEF, during PEF or subsequent PEF.

According to an embodiment, the addition of starch degrading enzymes is performed subsequent the application of the PEF.

According to an embodiment, the method is operated in batch or continuous-flow mode.

According to an embodiment the method is operated in continuous-flow mode.

According to an embodiment, the aqueous composition comprising oat material of the method provides for improved foaming stability.

According to an embodiment, the aqueous composition comprising oat material of the method provides for improved and/or increased foam density.

According to an embodiment, the aqueous composition comprising oat material of the method provides for increased foaming stability and improved and/or increased foam density.

According to a further embodiment, the aqueous composition comprising oat material of the method provides for improved foaming stability and optionally improved and/or increased foam density of a drink such as an oat-based drink.

An embodiment relates to an aqueous composition comprising oat material obtained from the method.

An embodiment relates to an emulsion comprising a vegetable oil and an aqueous composition comprising oat material obtained from the method, preferably for the preparation of an oat-based drink.

An embodiment relates to a method for the preparation of a foamed oat-based drink comprising providing an emulsion comprising a vegetable oil and an aqueous composition comprising oat material obtained from the method, subjecting the

SUBSTITUTE SHEET (Rule 26) emulsion to mechanical energy, such as stirring/whipping, for a time sufficient to transform the emulsion to a foamed oat-based drink.

An embodiment relates to an oat-based drink prepared from an aqueous composition comprising oat material obtained from the method.

An embodiment relates to an emulsion for the preparation of an oat-based drink comprising the aqueous composition comprising oat material obtained from the method and a vegetable oil.

According to an embodiment the method comprises heating the aqueous composition comprising oat material and hydrolytic enzyme to a temperature essentially inactivating enzymes, specifically hydrolytic enzyme. The temperature is preferably above about 80°C, above about 90°C, more preferably above about 100°C, such as above about 105°C. The temperature is maintained during a timeperiod sufficient for temperature to essentially inactivating enzymes, specifically starch degrading enzymes. The time-period may range from a few seconds to several minutes. Generally, the higher the temperature the shorter the time-period. At a temperature of about 105°C, about 10 seconds is often sufficient to destroy any enzymatic activity. The hydrolytic enzyme or enzymes are preferably enzymes capable of hydrolyzing alfa-glycosidic bonds. The starch degrading enzymes are preferably selected from the group consisting of alfa-amylase, beta-amylase, isoamylase, glucosidase such as alfa-D-glucosidase, glucanase such as exo(1-4)-alfa- D-glucanase, pullulanase and mixtures thereof. Alfa-amylase and beta-amylase are a preferred group of starch degrading enzymes.

The aqueous composition comprising oat material may also be referred to as oatbased drink or oat-drink or alternatively form the bases for an oat-based drink or oat drink.

The oat material is further subjected to PEF.

PEF can be operated in batch or continuous-flow mode. According to an aspect, the PEF is operated under continuous flow conditions. The average flowrate of the aqueous composition comprising oat material (through the PEF) may range from about 50 liter/hour up to about 1000 l/hour, preferably from about 100 l/hour up to about 500 l/hour, such as from about 100 l/hour up to about 160 l/hour. The applied

SUBSTITUTE SHEET (Rule 26) electric field (across the electrodes) is in the range from about 1 to 15 kV/cm, suitably from about 2 to 12 kV/cm, preferably from about 3 up to about 8 kV/cm. The energy density (also referred to as specific energy input) is from about 20 up to about 50 kJ/kg, suitably from about 10 up to about 40 kJ/kg, preferably from about 30 up to about 40 kJ/kg. The voltage applied to the electrodes may range from about 3 to 10 kV, suitably form about 5 to about 7 kV. The power delivery to the aqueous composition is a function of voltage, current and pulse width and is preferably in the range from about 1 ,0 up to about 2,0 kW, preferably from about 1 ,3 up to about 1 ,5 kW. The frequency may range from about 500 up to about 1500 Hz, preferably from about 400 up to about 700 Hz. The pulse width may range from about 5 up to about 15 ps. The treatment time of a volume element of the aqueous composition positioned between electrodes is from about 500 to 2000 ps. If the PEF is in continuous flow the treatment time is a function of the flowrate given a constant geometry of the electrodes. Any of the parameters of the PEF presented above may be combined in any justifiable way. Thus, the PEF may be characterized by one parameter or the combination of two or more parameters. Thus, according to an aspect the PEF may be characterized as having an electric field from about 1 to 15 kV/cm and an energy density from about 5 up to about 50 kJ/kg. According to a further aspect, the power of the pulsed electric field is the order of about 1 kW or more at an average flowrate of about 160 l/hour. According to a further aspect, the power of the pulsed electric field is from about 1 ,3 up to about 1 ,5 kW at a flowrate of about 160 l/hour.

The oat material may originate from any existing oat variants of the genus Avena including oat variants with hulls (Avena sativa) and oat variants without hulls (Avena nuda). If oat variants with hulls are contemplated the oat material should be provided without hull before being subjected to the method.

The oat material contemplated for the method should be heat treated. This heat treatment inactivates enzymes comprised in the oat material which may have a negative impact on any end-product comprising the oat material modified by the present method. More specifically, the heat treatment is capable of inactivating enzymes capable of oxidizing lipids contained in the oat material such as lipases and peroxidases. Thus, the oat material contemplated for the method should be de-hulled (or void of hulls) and be heat treated. The heat treatment of oat material, such as de-

SUBSTITUTE SHEET (Rule 26) hulled oat refereed to at oat groats, usually includes subjecting the oat groats to steam. The heat-treated oat groats may be rolled to form oat flake, or the oat groats may be milled into powder form such as an oat flour. Optionally, heat treated oat groats may be subjected to a second heat treatment prior to milling or rolling. The oat material is preferably heat treated and provided in particulate form, such as in powder from such as oat flour.

According to a further embodiment the method may comprise a step where macroscopic fibers remaining after starch hydrolysis may be removed by, for instance, filtration or centrifugation.

DESCRIPTION OF A PREFERRED EMBODIMENT

Oat slurry preparation

Dehulled heat-stabilized dry-milled oat kernels or oat flour or other oat material of similar kind can be used in the method of the invention. Oat flakes (AXA havregryn, 250 g, moisture content 11 .5 % w/w) were added to 1750 g of tap water at about 63 °C in a glass beaker disposed in a water bath at 65 °C and mixed by means of a propeller stirrer. During the mixing the temperature of the contents dropped to about 60 °C. The dry matter content of the so produced slurry thus was 11 .5 % w/w.

A first sample of the slurry was subjected to Pulsed Electrical Field (PEF) treatment in pilot plant equipment.

A second sample of the slurry was not treated with PEF and used for comparison.

Pulsed electrical field (PEF) treatment of oat slurry

The pulsed electrical field (PEF) applied to the oat slurry was provided by a Closed Environment Pulsed Electric Field Treatment (CEPT®) platform developed by Arcaroma AB, Lund, Sweden, https://www.arcaroma.com/; WO 2016/171610 A1 .

The CEPT platform consist of (i) a 4.2-kW pulse generator producing monopolar pulsating (near square-wave) electric pulses at a maximum peak voltage of 8 kV and

SUBSTITUTE SHEET (Rule 26) (ii) a PEF-chamber with optimal electrode geometry for continuous flow, comprising a treatment cavity, a casing and two 2-noble metal electrode units. The treatment was performed in continuous mode with the aid of a peristaltic pump and at a flow rate of 160 l/h.

A current was generated by applying a 5 to 7 kV voltage with a pulse repetition ranging from 500 to 1500 Hz at pulse width ranging from 5 to 15 ps on the slurry between the electrodes. The power delivered to the slurry (1 ,3 - 1 ,5 kW) was calculated as the product of voltage, current, frequency and pulse train. The energy density for PEF treatment provided to the oat slurry between the opposite electrode units ranged from 10 - 40 kJ/kg. The time of treatment resulting from multiple pulses in a summed pulse train ranged from 500 to 2000 ps.

Oat drink preparation

Starch degrading enzymes (48 pl BAN® 480 LS, alpha-amylase, Novozymes; 190 pl Secure®, exo-beta-amylase, Novozymes) were added to the slurry (1500 g of the above PEF treated one), comprising microbial exo-beta-amylase (https://biosolutions.novozymes.com/en/plant-protein/product s/secura; https://biosolutions.novozymes.com/en/plant-protein/products /ban) and bacterial alpha-amylase (https://biosolutions.novozymes.com/en/plant-protein/plant-b ased- dairy-alternatives) from Novozymes (Bagsvaerd, Denmark). Controlled hydrolysis of the starch was carried out for about 1 hour at 61-63 °C under continuous stirring to obtain a drinkable product with a viscosity similar to that of full-fat dairy milk.

Macroscopic fibers remaining after starch hydrolysis may be removed by, for instance, filtration or centrifugation.

Functionality assessment

The resulting oat drink has superior healthy attributes, nice taste, light color and natural oat flavor. Most important, its frothability, storage stability and foam density had been substantially improved by PEF treatment, as shown by comparison with an otherwise identical drink that had not undergone such treatment.

SUBSTITUTE SHEET (Rule 26) Foamability/Froathability

For foamability/frothability trials, the oat base was heated and frothed, alternatively rapeseed oil was added to the oat base, the drink was heated thoroughly, mixed and cooled overnight before testing the frothing. The added oil content was 1 ,5 g per 100 g of drink (6 g of oil in 394 g of oat base). A volume of 150 ml was employed in each frothing trial. The drink was poured into a commercial electric frother (type Melitta Cremio). The frother was started to heat and whisk the drink for a desired period of time at a temperature of 60-70 °C. The resulting product was transferred to a volumetric glass to assess, upon a delay of 30 sec, the height of the liquid and of the foam.

The oat base that had been PEF treated prior to the enzymatic reaction showed only slightly improved foaming characteristics, generally of 15 % or less.

Addition of vegetable oil to the oat base resulted in a substantially increased froth volume, the increase being of about 62% for the non-PEF treated oat drink (sample A) and 84% for the PEF treated oat drink (sample B). In general, PEF-treated oat drinks with added vegetable oil exhibited a foam volume increased by 20-50 % in comparison with that of non-PEF treated samples.

Reference is made to fig. 1 illustrating improved frothability of oat drink by added rapeseed oil (1 ,5 % by weight).

High energy PEF increased the temperature of the drink by up to 10 °C but did not affect its taste and color while increasing foam volume, yielding a foam of improved stability with smaller bubbles more uniform in size.

Storage stability

Addition of PEF improved the storage stability of the oat drink (the drink being a kind of combined emulsion and suspension). The drink was left to settle overnight in a refrigerator at about 6 °C. The volume percentage of the watery upper phase (about 10 %) was substantially smaller for the oat drink that had been PEF-treated than for a corresponding non-PEF-treated oat drink (about 30 %).

SUBSTITUTE SHEET (Rule 26) Reference is made to fig. 2 illustrating the improved storage stability of a PEF-treated oat drink, % of oat drink volume remaining upon storage (% lower/bottom phase).

Furthermore, the addition of PEF also increased the density of the froth. In this trial an oat base was obtained as described above in the section 'Oat drink preparation’. Furthermore, rapeseed oil was added to the oat base as described above, thereby forming an emulsion. The so formed emulsion was pasteurized/sterilized at a temperature of 140°C during 4 sec and homogenized. The pasteurized/sterilized emulsions were stored from 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks, respectively. The stored emulsions were frothed (foamed) according to the protocol outlined in the section ‘Foamability/Frothability’.

Table 1 . Density of the froth measured 10 minutes after the frothing protocol as a function of storage period of the emulsion.

SUBSTITUTE SHEET (Rule 26) Table 2. Percentage of the froth based on total volume of froth (foam) phase and aqueous phase measured after 10 minutes after the frothing protocol as a function of storage period of the emulsion.

Figures 3 and 4 graphically present the data of tables 1 and 2.

SUBSTITUTE SHEET (Rule 26)