EP3383198A1

EP3383198A1 - Oat-based product and process of manufacture

Info

Publication number: EP3383198A1
Application number: EP16805817.0A
Authority: EP
Inventors: Pierre Jean Dupart; Luca RUFFINO; Jean-Louis Savoy
Original assignee: Nestec SA
Current assignee: Societe des Produits Nestle SA
Priority date: 2015-12-03
Filing date: 2016-12-02
Publication date: 2018-10-10
Also published as: CN108347975A; RU2018123200A3; SG11201803882PA; WO2017093538A1; PH12018500666A1; MX2018006539A; RU2018123200A; BR112018009295A2; BR112018009295A8

Abstract

The invention relates to extruded oat-based products, and their process of manufacture. The invention also relates to compositions which comprise extruded oat-based products, for instance food or beverage compositions.

Description

OAT-BASED PRODUCT AND PROCESS OF MANUFACTURE

TECHNICAL FIELD

BACKGROUND OF THE INVENTION

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Oat (Avena sativa) is a cereal grain suitable for human consumption. Oat is generally considered as a health food, owing to its high content in beta-glucan. I ndeed, it is now recognised that regular consumption of beta-glucans contributes to maintenance of normal blood cholesterol concentrations. Following the opinion of the Panel on Dietetic Products, Nutrition and Allergies (N DA) the European Food Safety Authority (EFSA), pursuant to Regulation (EU) No. 1160/2011 of the Commission, foodstuffs through which 3 g/day of oat beta-glucan are consumed (1 g of oat beta-glucan per portion) are allowed to display the following health claim : "Oat beta-glucan reduces the cholesterol level in the blood. The lowering of the blood cholesterol level can reduce the risk of coronary hea rt disease." It is also considered that beta-glucan may have glycaemia and digestion regulating properties. I n addition, oat proteins are relatively rich in tryptophan, which is an essential amino acid in the human diet. Oat is also rich in antioxidants, such as avenanthramide, tocopherols and tocotrienols.

Beta-glucans are located throughout the starchy endosperm. They are concentrated in the bran. Beta-glucans usually represent 2-8% (dry weight) of the whole grain oat. The content of dietary fibre and beta-glucan varies between oat products. For example, conventional oat bran products contain 15-32 % dry weight of dietary fibres of which 8-12% dry weight a re beta-glucan.

It is often difficult to reach the required content of beta-glucan in foods with reasonable serving sizes, due to the relatively low concentration of beta-gluca n in oat. Purified soluble beta-glucan can be added during the production of the food product. However, due to the difficulty to purify beta-glucan, this is an expensive solution. Another approach consists in an enzymatic pre-treatment of the oat component to produce highly soluble beta-glucan, for example with alpha-amylases, followed by drum or spray drying. However, this approach introduces additional processing steps, is quite expensive and generally does not yield high rates of soluble beta-glucan.

Additionally, beta-glucan is sensitive to mechanical processing. Under high mechanical processing, beta-glucan is broken down into smaller fragments, which leads to a partial loss of the health benefits associated with intact or long-chain beta-glucans.

To avoid this issue, it is known to supplement a mechanically-processed product with beta-glucan, for example purified beta-glucan. However, in practice, this may lead to in-pack segregation and a non-homogeneous distribution of the added beta-glucan in the fina l composition. Altogether, the recommended daily beta-glucan intake cannot be ensured. In addition, as mentioned above, this is a rather expensive solution.

A typical example of oat consumption is porridge, prepared either in the traditional manner with rolled oat, or in a more consumer-friendly manner with pre-cooked oat flakes. Traditional porridge is prepared by cooking rolled oat, or pre-cooked oat flakes, in water or milk. The viscosity of the porridge quickly increases and if cooking is too long, the resulting product becomes very thick and forms lumps which are difficult to consume. For instance, oat flakes or oat porridges are commercialised under brands such as UNCLE TOBYS, or QUAKER OATS.

Traditionally, oat flakes are manufactured in a relatively simple process. The outer floral envelope (the hull or husk) of the oat grain is removed from the caryopsis (the groat). The groat is considered as the whole oat grain. The groats are then steamed to inactivate naturally occurring lipases. Indeed, groats are naturally rich in lipase and fat that is susceptible to oxidative rancidity due to lipase enzymatic activity. Then the steamed groats may be cut into pieces. Next, the cut or whole oat groats are flaked by passing in a roller, thus providing oat flakes, also known as rolled oats. Rolled oats (or oat flakes) can be used to prepare porridge, usually requiring cooking of the rolled oat.

Products such as porridges having a high content of oat often display a strong and distinctive "oaty" taste that may not be appreciated by consumers. GB 2209457 A discloses an example of a process for manufacturing pre-cooked oat flakes. In this process, pre-treated oat flakes are steeped in water during 30 minutes up to about 3h, to reach moisture content between 16 and 23% by weight, then cooked in a cooker extruder, discharged, cut at the outlet of the extruder, and finally dried to moisture content between 2 and 12% by weight. The pre- treatment comprises a steaming step to inactivate naturally occurring enzymes in the oat grains. Typically, the extrudate is cut into pellets at the outlet of the extruder, and then again formed into flakes by pressure rolling. This process requires steeping of the pre-treated oat, and pressure rolling of the extrudate. Both increase the complexity of the manufacturing process.

US 5,997,934 relates to a process for the manufacture of cooked cereals or dry pet food which comprises preparing a mixture of water and a dry premix mainly comprising cereal flour or semolina, cooking the mixture and extruding it by pressing it through an extrusion die with the aid of a gear pump. The gear pump is located downstream of a mixing and cooking device and upstream of the extrusion die. All the examples use corn flour as the main cereal.

WO 2010/140963 A2 relates to a method for producing an oat-based food product by extrusion cooking of an oat slurry. The slurry is prepared by mixing oat components with water. The oat components include endosperm-starch rich oat flour, oat dietary fibres, protein, and oil derived from oat grains. Preferably, the oat components are obtained from oat grains that have not been previously heat-treated.

US 4,497,840 relates to a food product prepared from oat bran.

US 2010/0112167 relates to the preparation of soluble oat or barley flour using a low- shear extrusion process to dextrinize and completely gelatinize the oat or barley flour. A wet mix is added into a single screw extruder. The powdered product obtained completely dissolves when reconstituted in liquid.

US 5,372,826 relates to ready-to-eat cereal flakes having edible particulate matter embedded therein and attached thereto, as well as a process for preparing said cereal flakes. More specifically, the present invention comprises a ready-to-eat cereal flake comprising cooked cereal grain and edible particulate matter embedded therein in a substantially uniform manner; a ready-to-eat cereal flake having edible particulate matter embedded therein and additionally having edible particulate matter attached to the surface of said flake; and processes for preparing such ready-to-eat cereal flakes.

EP 1219177 Al relates to a process for the manufacture of cooked cereals or dry pet food which comprises preparing a mixture of water and a dry premix mainly comprising cereal flour or semolina, and pressing the mixture, with the aid of a gear pump, firstly through a heat exchanger wherein it is cooked and then through an extrusion die, an apparatus for carrying out the process and a product obtainable by the process. It is desirable to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. In particular, it is desirable to provide a simple process to manufacture an oat-based product having excellent organoleptic properties, including taste and texture, to bring the health benefits of oats to the consumers in a versatile and easy-to- use manner. For example, it is desirable to provide a process to manufacture an oat-based product which can be used as an ingredient in the manufacture of various food products or beverage products.

SUMMARY OF THE INVENTION

The inventors have surprisingly found that cooking-extrusion of a dry mix containing a high content of oat component (more than 50% by weight) can be performed with relatively low water (less than 25 parts by weight of water per 100 part by weight of dry mix). Additionally, the resulting product showed not only a high content of intact beta-glucan allowing delivering the health benefits of oat, but also demonstrated excellent organoleptic properties for the consumer.

To this end, an embodiment of the invention proposes a process for manufacturing oat-based pieces, said process comprising the steps of:

a) feeding a dry mix into a cooker-extruder, said dry mix comprising from 50% to 99.9% by weight of an oat component, and from 0.1 to 2% by weight of an antioxidant,

b) injecting water into the cooker-extruder, in a proportion ranging from 10 to 25 parts by weight of water per 100 parts by weight of dry mix, to obtain a dough,

c) cooking the dough downstream of water injection at a barrel temperature above 120°C, d) extruding the dough at a specific mechanical energy of 40 to 135 W.h/kg of dry mix and at a flow of 2.5 to 10 kg/h/mm² of dry mix and of die surface,

e) cutting the rope of dough into pieces and expanding the pieces, thereby producing the oat- based pieces.

Another embodiment of the present invention proposes a product consisting of cooked-extruded oat-based pieces, wherein said oat-based pieces comprise 0.1% to 2% by weight of an antioxidant, and from 50% to 99.9% by weight of oat component, wherein the product comprises from 2 to 16 % by weight of beta-glucan, wherein at least 50% of the beta- glucan has a molecular weight of at least 10⁶ g/mol.

Still another embodiment of the present invention proposes a product consisting of extruded oat-based pieces obtainable by the process disclosed in the invention. Another embodiment of the invention proposes a composition comprising the product according to the invention, and at least one ingredient selected from sugar, fruit pieces, vegetable pieces, nut pieces, meat pieces, fish pieces, milk-based powder, aroma, and mixes thereof.

As mentioned, an embodiment of the invention relates to a process for manufacturing oat-based pieces by extrusion-cooking. As will be shown below, especially in the examples, the cooked-extruded oat-based pieces are quite versatile in their final use. Said oat-based pieces can contain a very high amount of oat, including up to 99.9 wt% of oat, and still retain a pleasant texture after reconstitution in water or milk. This is quite an achievement as traditional oat porridges, for instance, can become extremely thick and form lumps which are difficult to consume. On the contrary, upon reconstitution in water or milk, the oat-based pieces of the present invention can retain their overall shape and do not form lumps even if an insufficient amount of liquid (water or milk) is used for reconstitution.

Another advantage of the present invention is that the oat-based pieces and compositions containing such oat-based pieces can be rehydrated quickly. Preparing a ready- to-eat or -drink product requires less time than preparing a traditional oat porridge. Indeed, preparation of traditional oat porridge requires cooking of the oat for at least 5 to 15 minutes, depending on whether it is prepared from oatmeal (non-steamed oat) or rolled oat flakes (steamed oat). The oat-based pieces of the present invention can be rehydrated in cold or warm liquids in less than one minute and can be consumed readily. This saves time for the consumer and makes the oat-based pieces and compositions convenient to use.

Another advantage of the present invention is that it provides a highly digestible product due to the full or high gelatinisation of the starches. Indeed, the degree of gelatinisation can reach 80% to 100%. In comparison, rolled oat flakes reach a degree of gelatinisation below 40%, which is known to produce digestion discomfort.

Another advantage of the present invention is the reduction of strong typical oaty taste found in traditional roller flakes.

Another advantage of the present invention is that the product when reconstituted in cold or hot liquid does not present the typical gluey texture of rolled oat flakes.

Finally, the oat-based pieces contain a high level of beta-glucan. Thereby, they can provide the recognized health benefits credited to oat in a single serving, together with the desired organoleptic properties, such as an expanded texture, without a gluey texture. In addition, the typical "oaty" taste, which some consumer dislike, can be reduced. These and other aspects, features and advantages of the invention will become more apparent to those skilled in the art from the detailed description of embodiments of the invention, in connection with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the impact of extrusion on the structure of oat beta-glucan.

DETAILED DESCRIPTION OF THE INVENTION

As used in the specification, the words "comprise", "comprising" and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

As used in the specification, the word "about" should be understood to apply to each bound in a range of numerals. Moreover, all numerical ranges should be understood to include each whole integer within the range.

As used in the specification, the singular forms "a", "an", and "the" include plura l referents unless the context clearly dictates otherwise.

Unless noted otherwise, all percentages in the specification refer to weight percent. The expressions "weight %", "% by weight" and "wt %" are synonymous. They refer to quantities expressed in percent on a dry weight basis.

Unless defined otherwise, all technical and scientific terms have and should be given the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The term "instant products" refers to food and beverage products that do not need to be cooked prior to consumption. I nstant products can be easily and quickly reconstituted in a warm or cold liquid by the consumer for immediate consumption by contrast to food products that require cooking or soaking for a long period of time, such as more than 5 minutes.

The term "oat component" refers to ingredients based on oat, such as oat groat, rolled oats, cut oats, cut groats, oat flour, or whole oat flour. Pure or refined ingredients ca n be obtained from oat components, such as beta-glucans or avenanthramides. For the purpose of this specification, such pure or refined ingredients are not considered as "oat com ponents". However, they can be added during the manufacturing process, for instance in the dry mix, to increase the content of this ingredient in the oat-based pieces. Similarly, for the purpose of this specification, oat fibres such as oat bran, other oat fibre and/or oat hulls are not considered as "oat components", but they can also be added during the manufacturing process, for instance in the dry mix, to increase the fibre content of the oat-based pieces.

The terms "oat-based piece" or "oat piece" refer to cooked-extruded products made according to the present invention.

The term "comminution" refers to the reduction of the particle size of a solid material, for instance by crushing, grinding, milling or other processes.

The term "water activity" (i.e Aw) is defined as the partial vapour pressure of water in a substance divided by the standard state partial vapour pressure of water. Water activity is a conventional parameter in the food industry. It is an important parameter for food product design and food safety. Indeed, food designer use water activity to formulate shelf-stable products. If a product is kept below a certain water activity, then growth of moulds is inhibited, resulting in a longer shelf-life. Water activity is also an important parameter to limit moisture migration within a food product. Therefore, the water activity is used to predict how much moisture migration can affect the final product.

The term "gelatinisation degree" refers to the degree of starch gelatinisation resulting from the breakdown of the intermolecular bonds of starch molecules in the presence of water and heat. Gelatinisation generally improves the availability of starch for amylase hydrolysis, which improves digestibility.

The process of manufacturing the oat-based pieces comprises several steps: a) feeding a dry mix into a cooker-extruder, b) adding water into the cooker-extruder to obtain a dough, c) cooking the dough, d) extruding the dough, e) cutting the rope of dough into pieces and expanding the pieces, and f) drying the pieces.

This may appear as a quite standard extrusion-cooking process. However, the inventors believed that extruding a dough with a high oat content (e.g more than 25% w/w of the dry mix) was difficult, if not impossible. Indeed, the high level of fat contained in oat combined with low water availability due to the absorption of water by the beta-glucans could result in the blockage of the extruder. Moreover, the increase in specific mechanical energy (SME) necessary to extrude dough with a high oat content could impact the integrity of beta- glucan. The inventors therefore believed that a high amount of water, such as more than 35 parts by weight of water per 100 parts by weight of dry mix, was needed to extrude a dough with a high oat content without damaging the extruder. However, adding more water raised another problem. Indeed, adding more water to the dough would result in a decreased pressure in the extruder. As a consequence, the expansion of the extruded product would be impaired and this would lead to pieces with a hard texture due to the lower expansion. Moreover, cutting the product at the die outlet would become difficult due to the too high water content, which would prevent the manufacture of pieces with a defined shape. Additionally, due to the high amount of water remaining in the extruded pieces, the drying step after extrusion would be extended and therefore would require more energy.

Surprisingly, the inventors were able to demonstrate that it was possible to extrude a dough prepared with a dry mix which comprises a very high amount of oat component, such as above 50 wt%, with a relatively low amount of water, such as from 10 to 25 parts by weight of water per 100 parts by weight of dry mix, without affecting the expansion properties and therefore the texture of the extruded product, also without impairing an efficient cutting of the extruded product thereby allowing the manufacture of extruded pieces with defined shapes, and without impacting the integrity of beta-glucans in the extruded oat-based pieces.

The dry mix can be fed into the cooker-extruder as a blend, or as separate dry ingredients. Preferably, the dry mix is neither preconditioned nor pre-treated before feeding into the extruder. This means that the dry mix is not pre-heated (by steam injection for example), or wetted. This removes the risk of unwanted modifications of the dry mix such as sticking of the ingredient together or too early starch gelatinisation. This also limits the input of water during the manufacturing process.

The dry mix comprises from 50 wt% to 99.9 wt% of an oat component, and from 0.1 wt% to 2 wt% of an antioxidant. In addition to the oat component and the antioxidant, the dry mix may further comprise dry ingredients such as cereals other than oat, fruit, vegetable or legumes, milk-based ingredients, sweeteners, colorants, flavourings, soluble or insoluble fibres, or vitamins and minerals. Preferably, the dry ingredients are provided as dry powders.

Traditionally, oat grains are first dehulled, thereby providing raw oat groats. Raw oat groats are then steamed to inactivate lipases. The steamed oat groats are then kilned, which means they are dried using dry heat. The kilned oat groats are then flaked into oat flakes. Traditionally, oat flakes are used as a starting material for producing standard oat flour. Oat flour may also be prepared by milling kilned or non-kilned oat groats directly. However, flour made from raw oat groats is subject to rancidity issues.

Preferably, the oat component comprises raw oat, groats, milled oat groats, steamed oat groats, kilned oat groats, oat flakes, standard oat flour, whole grain oat flour, or mixes thereof. In an embodiment, the oat component in the dry mix consists essentially of standard oat flour, oat flakes, or mixes thereof. In another embodiment, the oat component consists of whole grain oat flour. Preferably, whole grain oat flour is made from whole grain groats, such as raw groats. In a preferred embodiment, the oat component in the dry mix comprises raw oat groats, raw oat flour, and mixes thereof. In another preferred embodiment, the oat component comprises raw oat groats and/or raw oat flour, together with standard oat flour and/or oat flakes. In yet another preferred embodiment, the oat component in the dry mix consists essentially of raw oat groats, raw oat flour, and mixes thereof. For cost reasons, it may be interesting to use raw oat groats, raw oat flour, and mixes thereof, as the oat component, because they have been less transformed than standard oat flour or oat flakes. Preferably, the oat component comprises the starchy endosperm, the germ and the bran of oat grains, thereby providing starches, proteins and fibres.

In an embodiment, the dry mix comprises at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, or at least 85 wt% of an oat component. In an embodiment, the dry mix comprises up to 99.9 wt%, up to 99.5 wt%, up to 99 wt%, up to 98 wt%, up to 97 wt%, up to 96 wt%, up to 95 wt%, or up to 90 wt% of an oat component. For instance, the dry mix comprises from 50 wt% to 99.9 wt% of an oat component, preferably from 55 wt% to 99.5 wt% of an oat component, such as from 60 wt% to 99 wt% of an oat component. As mentioned above, the oat component comprises preferably oat groats, oat flakes, oat flour, or mixes thereof. The oat component may possibly comprise raw oat components. In a preferred embodiment, the oat component consists essentially of oat groats, oat flakes, oat flour, or mixes thereof.

As mentioned above, the dry mix also comprises from 0.1 wt% to 2 wt% of an antioxidant. Examples of antioxidants include disodium phosphate, dipotassium phosphate, tocopherol, rosemary extract, and mixes thereof. The antioxidant is an important ingredient as it improves shelf-life by reducing hydrolytic rancidity and fat oxidation. For instance, the dry mix comprises from 0.1 wt% to 1.8 wt%, or from 0.1 wt% to 1.6 wt%, or from 0.1 wt% to 1.5 wt% of an antioxydant. For instance, the dry mix comprises from 0.1 to 1 wt% of dipotassium phosphate, preferably from 0.2 to 0.5 wt% of dipotassium phosphate. For instance, the dry mix comprises from 0.1 to 0.5 wt% of tocopherol, preferably 0.1 wt% of tocopherol. Preferably, the dry mix comprises a 0.1 to 2 wt% of a combination of tocopherol and dipotassium phosphate.

In an embodiment, the dry mix further comprises 2.5 to 15 wt% of added beta-glucan. Contrary to what the inventors expected, it is possible to add beta-glucan (i.e purified beta- glucan) in the dry mix, i.e. before extrusion, and still manage to extrude the food pieces despite the water retention properties of beta-glucan, and retain the beta-glucan structure in the extruded product. This leads to a high beta-glucan content of the extruded pieces. In the extruded pieces, the beta-glucan comes from the oat component and the optional added beta-glucan. Usually, the added beta-glucan consists in a composition of purified beta-glucan together with a carrier, such as maltodextrin. Since the beta-glucan is part of the extruded pieces, issues of in-pack migration of powder ingredients in a particulate food composition, are avoided. The beta-glucan content per serving can be guaranteed to the consumer.

As already mentioned, the dry mix may further comprise at least one ingredient selected from cereal flour other than oat, vegetable powder, fruit powder, legume flour, milk powder, sweetener, colorant, soluble or insoluble fibres, vitamins, minerals. The dry mix may comprise up to 49.9 wt% of these additional ingredients.

Cereals other than oat include rice, rye, wheat, corn, buckwheat, millet, barley, sorghum, quinoa, or amaranth. Preferably, cereals are provided as flour. Adding cereals in the dry mix may be interesting in order to mitigate the taste of oat for instance. For instance, the dry mix comprises from 10 to 49 wt%, preferably 25 to 49 wt%, of cereal other than oat, preferably cereal flour, such as rice, wheat or corn flour. Mixing several cereals is possible. Cereals are interesting especially for the carbohydrate content. They also provide fibres.

Fruit, vegetable and legumes may be interesting ingredients to provide colour, or flavour to the oat-based pieces. In addition, fruits, vegetables and legumes contain interesting dietary fibres, macronutrients, such as proteins, or phytonutrients, such a polyphenols. Preferably, fruit, vegetables and legumes are provided as dry powders or flours. For instance, the dry mix comprises from 5 to 30 wt% of fruit and/or vegetable powder.

Examples of fruits include apple, blackberry, cherry, date, grape, orange, passion fruit, pear, peach, pineapple, plum, raspberry, and strawberry. Examples of vegetables include artichoke, broccoli, carrot, cauliflower, courgette, pumpkin, spinach, or tomato. Examples of legumes include beans, chick peas, kidney beans, lentils, or peas. Combinations of several fruits, vegetables and/or legumes can be considered.

Milk powder can be added into the dry mix. Milk powder is useful to improve the protein content of the oat-based pieces. Examples of milk powders include powder made from milk, semi-skim milk, skim milk, milk proteins and combinations thereof. Examples of milk proteins are casein, caseinate, casein hydrolysate, whey, whey hydrolysate, whey concentrate, whey isolate, milk protein concentrate, milk protein isolate, and combinations thereof. Furthermore, the milk protein may be, for example, sweet whey, acid whey, a- lactalbumin, β-lactoglobulin, bovine serum albumin, acid casein, caseinates, a-casein, β-casein and/or γ-casein. For instance, the dry mix comprises from 5 to 40 wt% of milk powder.

Sweeteners include natural sweeteners and sugar substitutes. Examples of natura l sweeteners include agave nectar, date sugar, fruit juice concentrate, honey, maple syrup, molasses. Examples of sugar substitutes include acesulfame potassium, aspartame, neotame, saccharin, sucralose, advantame, erythitol, hydrogenated starch hydrolysate, isomalt, lactitol, maltitol, mannitol, sorbitol, xylitol, stevia extracts, tagatose, trehalose. For instance, the dry mix comprises up to 15 wt% of sweetener. For instance, the dry mix comprises from 3 to 15 wt% of sugar or other natural sweeteners, or an amount of sugar substitutes sufficient to provide an sweetness perception equivalent to 3 to 15 wt% of sugar. In any case, the amount of natural sweeteners and sugar substitutes should respect the applicable regulation.

The dry mix may also comprise soluble or insoluble fibres instead of, or in addition to added beta-glucan. Preferably, fibres include inulin and fructo-oligosaccharides. For instance, the dry mix comprises up to 30 wt%, preferably from 5 to 25 wt%, of fibres other than added beta-glucan. For instance, the dry mix comprises up to 25 wt% of inulin, such as from 5 to 25 wt% of inulin, or from 10 to 24 wt% of inulin.

In addition, the dry mix may also comprise vitamins, minerals and other nutrients including vitamin A, vitamin Bl, vitamin B2, vitamin E, vitamin K, vitamin C, vitamin D, folic acid, inositol, niacin, biotin, panthotenic acid, choline, calcium, sodium, phosphorous, iodine, magnesium, copper, zinc, iron, manganese, chloride, potassium, selenium, chromium, molybdenium, taurine and L-carnitine. Minerals are usually in salt form. The presence and amount of the specific minerals and other vitamins may vary depending on the intended fortification and the targeted consumer. In any case, fortification levels should respect the applicable regulation. Fortification could be added in the dry mix prior to extrusion or directly into the extruder. Usually, the vitamins, minerals and other nutrients represent less than 2 wt% of the dry mix.

In an embodiment, the dry mix further comprises up to 1 wt% of calcium carbonate. Addition of calcium carbonate improves the expansion properties of the dough. For example, the dry mix comprises 0.5 wt%, or 0.6 wt%, or 0.7 wt%, or 0.8 wt% or 0.9 wt% of calcium carbonate. Hence, the dry mix may have the following composition:

Oat component 50 to 99.9 wt%

Antioxidant 0.1 to 2 wt%, preferably as a combination of tocopherol and dipotassium phosphate

Added beta-glucan up to 15 wt%, preferably 2.5 to 15 wt%

Non-oat cereal up to 49.9 wt%, preferably 10 to 49 wt%, as cereal flour for instance

Fruit or vegetable up to 49.9 wt%, preferably 5 to 30 wt%, as fruit or

vegetable powder

Milk up to 49.9 wt%, preferably 5 to 40 wt%, as a powder

Sweetener up to 15 wt%, preferably 3 to 15 wt% of sugar, or the

amount of sweetener or sugar substitute sufficient to provide an equivalent sweetness perception

Soluble or insoluble fibres up to 30 wt%, preferably 5 to 25 wt%, of fibres other than beta-glucan, such as 5 to 25 wt% of inulin

Vitamins and minerals usually less than 2 wt% of the dry mix

Calcium carbonate up to 1 wt%, preferably 0.1 to 0.9 wt%

The cooker-extruder comprises several successive barrels equipped with a screw. The dry mix is fed into the first barrel. After feeding the dry mix into the first barrel of the cooker- extruder, water is added by injection in the first or the second barrel, in a proportion of 10 to 25 parts by weight of water per 100 parts by weight of dry mix, to obtain a dough. This is equivalent to a content of about 9.1% to about 20% of water in the dough, not taking into account the traces of water contained is some ingredients of the dry mix. Preferably, water is injected in the cooker-extruder in a proportion ranging, per 100 parts by weight of dry mix, from 12 to 24 parts by weight of water, preferably, from 13 to 23 parts by weight of water, more preferably from 14 to 22 parts by weight of water, and most preferably from 18 to 21 parts by weight of water.

Said another way, the dough comprises from about 80 wt% to about 90 wt% of dry matter (from the dry mix) and from about 10 wt% to about 20 wt% of water. Preferably, the dough comprises from about 82 wt% to about 88 wt% of dry matter (from the dry mix), and from about 14 wt% to 18 wt% of water.

Keeping the amount of injected water between 10 and 25 parts by weight of water per 100 parts by weight of dry mix allows extruding a dough having a high oat content while avoiding damage to the extruder, ensuring a pressure in the extruder that generates the desired expansion of the extruded product, and avoiding a too high moisture content of the dough which would results in sticking of the dough on the knife and therefore bad cutting of the extruded pieces.

The inventors have found that when the dry mix contains soluble fibres in addition to beta-glucan, such as inulin, the water content of the dough can be as low as 10 parts by weight of water per 100 parts by weight of dry mix.

The inventors have found that when the main fibre component is beta glucan, the amount of water injected in the cooker-extruder ranges from 12 to 25 parts by weight of water per 100 parts by weight of dry mix. This is particularly the case when the dough does not contain inulin.

Preferably, the water is injected into the cooker-extruder at a temperature below 50°C. If the injected water is warmer than about 60°C, there is a risk that the starches in the dry mix gelatinise too early in the extrusion process. The gelatinisation of the starches at this stage of the process could cause the blockage the extruder. Preferably, the temperature of the injected water is below 40°C, and most preferably below 30°C. Due to friction within the extruder, the temperature of the barrels increases over usage, between the start and the end of a production batch. As a consequence, the barrel temperature upstream of the water injection may increase over time, which could also result in premature gelatinisation of the starches in the dry mix in the first barrel. Injecting water at a relatively low temperature helps cooling the extruder, and reduces the risk of premature gelatinisation.

Cooking of the dough takes place downstream of water injection at a barrel temperature above 120°C.

After injection of water, the dough is blended and cooked in the cooker-extruder. The extruder can be a single screw or a twin screw extruder. To avoid degradation of the starches and the fibres, in particular the beta-glucan from the oat component, and to cook the dough within the extruder slowly, it is preferable to select a rather long extruder configuration. For instance, the extruder can comprise 4 to 8 barrels, so that the L/D ratio of the screw (L: screw length; D: screw diameter) is between 14 and 30. In another embodiment, the extruder can comprise 4 to 6 barrels, so that the L/D ratio of the screw is between 14 and 25. Rotation of the screw adds mechanical energy to the system, which heats the dough up.

In addition, the barrel temperature may be controlled, for instance by circulating hot or cold water in a jacket around the extruder. First, applying a low temperature on a first barrel merely results in the mixing and conveying of the product in the first part of the extruder. A low temperature is a temperature below the temperature needed to cook to dough. Further down the extruder, a barrel is equipped with a screw having smaller screw flight than in the first barrel. This restricts the volume and increase the resistance to movement of the dough. As a result, the dough fills the barrel and the space between the screw flights and is compressed. As it moves further along the barrels, the screw kneads the dough into a semisolid, plasticized mass. When the dough is heated at a higher temperature (for example above 100°C) then it cooks (i.e. extrusion cooking). The temperature should be controlled over the entire length of at least one barrel. The barrel temperature can have an impact on the organoleptic properties of the extruded product, such as on the texture and/or the taste. For example, a barrel temperature below 120°C would not allow a sufficient expansion of the extruded product. On the other hand, a barrel temperature above 150°C (for example, a barrel temperature at 152°C) could result in the degradation of oat antioxidants and thereby impact the shelf-life of the extruded oat product. The inventors have found that when a too high cooking temperature, i.e. at about 155°C and above, was used, lipid oxidation could occur as early as about 2 weeks after production.

In one embodiment, the extrusion cooking is performed at a barrel temperature above 120°C. In another embodiment, the barrel temperature is comprised between 120 °C to 150°C. In yet another embodiment, the barrel temperature is comprised between 125 °C to 145°C, or between 130°C to 140°C. Examples of temperature profiles are disclosed in the examples below (see Table 1). For example, the barrel temperature can be 130°C, or 135°C, or 140°C, or 145°C, or l50°C or l55°C.

When a viscous product is sheared in the extruder, the mechanical energy from the engine is converted into heat by friction. Mechanical energy is dissipated throughout the product by shear. Shear also affects the product structure. The process according to the present invention is a mild-shear extrusion process. The term "mild-shear extrusion" means that the specific mechanical energy input is between about 40 and 140 W.h/kg of finished product. The specific mechanical energy (SME) is a scale-independent measure of the mechanical energy spent to manufacture an extruded product. It correlates to the mechanical energy input per unit mass of product.

The value of SME is an important extrusion parameter to control as it has an impact on the expansion of the extruded product. Indeed, extruding the dough with a SME below 40 W.h/kg would result in limited expansion of the extruded pieces, resulting in a hard product having poor rehydration properties. On the other hand, when a dough with a high oat content is extruded, a too high SME (i.e above 135 W.h/kg) has a negative effect on the product: the starch is hydrolysed instead of being gelatinised, resulting in the complete dissolution of the pieces after reconstitution in a liquid giving. Instead of obtaining a product with identifiable shapes, a porridge-type product is obtained, and the beta-glucan would be freed, leading to an increased viscosity of the product after reconstitution.

Preferably, when the dough contains soluble fibres, such as inulin, in addition to beta- glucan, the dough is extruded with a specific mechanical energy (SME) from 40 to 135 W.h/kg, or from 45 to 135 W.h/kg, or from 50 to 135 W.h/kg.

Preferably, when main fibre component of the dough is beta glucan, the dough is extruded with a specific mechanical energy (SME) from 60 to 135 W.h/kg, or from 70 to 135 W.h/kg, or from 80 to 135 W.h/kg. In another embodiment, the SME is from 65 to 135 W.h/kg, or from 70 to 135 W.h/kg, or from 75 to 135 W.h/kg or from 80 to 135 W.h/kg. In another embodiment, the SME is from 80 to 135 W.h/kg, or from 82 to 135 W.h/kg, or from 84 to 135 W.h/kg or from 86 to 135 W.h/kg. In yet another embodiment of the invention, the SME is form 65 to 130 W.h/kg, or from 70 to 125 W.h/kg or from 75 to 120 W.h/kg. This is particularly the case when the dough does not contain inulin.

The flow rate of the dough is also an important extrusion parameter. Indeed, a flow rate below 2.5 kg/h/mm² would not allow the expansion of extruded product, due to an insufficient pressure drop at the die of the extruder, thereby impacting the texture of the extruded product. On the other hand, a flow rate above 10 kg/h/mm² would results in a very high pressure drop at the die of the extruder, leading to the blockage of the die and of the extruder.

Twin-screw extruders can be operated at a higher speed than single-screw extruders, providing higher flow rates, higher shear rates and better mixing.

In an embodiment, the flow rate is from 2.5 to 10 kg/h/mm² of dry mix and die surface. In another embodiment, the flow rate is from 2.5 to 9.5 kg/h/mm², or from 2.5 to 9.0 kg/h/mm²or from 2.5 to 8.5 kg/h/mm², or from 3 to 8.5 kg/h/mm², or from 3 to 8 kg/h/mm², or from 3 to 7.5 kg/h/mm² or from 3 to 7.0 kg/h/mm² of dry mix and die surface.

In an embodiment, the dough is extruded at a specific mechanical energy from 60 to

135 W.h/kg and at a flow from 2.5 to 10 kg/h/mm² of dry mix and of die surface, preferably at a specific mechanical energy from 84 to 135 W.h/kg and at a flow from 2.8 to 8.5 kg/h/mm² of dry mix and of die surface, and more preferably at a specific mechanical energy from 84 to 135 W.h/kg and at a flow from 3.0 to 7.0 kg/h/mm² of dry mix and of die surface.

The dough is then extruded under atmospheric pressure through a perforated plate or die, with a design specific to the final food product. The extruded dough is then cut into pieces of specific thickness with rotating blades. As the dough emerges under pressure from the die or perforated plate, it expands to the final shape and cools rapidly as moisture is flashed off as steam. The size of the extruded pieces can vary depending on the cutting applied. For example, extruded pieces can be obtained with an average size varying from 0.2 mm to 1.5 cm.

The pieces are then dried, for example in a fluid bed drier or belt band drier. In an embodiment, the expanded pieces are dried to a water content of 3% to 4% by weight.

In an embodiment, the process comprises a step of coating the oat-based pieces. Coating can be performed, for instance, by spraying, in a tumbler or a coating pan. The coating composition may be a water-soluble coating or a fat-based coating. Generally, water-soluble coating is applied on the oat-based pieces before drying. Examples of water-soluble coatings are the sugar based slurry applied on breakfast cereals. Generally, fat-based coating is applied on the oat-based pieces after drying. Examples of fat-based coatings are the fat based slurry applied on savoury handheld snacks.

In an embodiment, the extruded pieces are then comminuted, or milled, to an average size ranging from 0.1 to 3 mm. For example, the extruded pieces can be comminuted to a size of 0.1 mm, or to a size of 0.15 mm, or to a size of 2 mm, or to a size of 2.5 mm or to a size of 3 mm. Comminution may be performed using a standard mill, followed by sieving to the desired particle size.

Another aspect of the invention is a product consisting of cooked-extruded oat-based pieces. Such pieces may be manufactured following the process described above. Hence, the oat-based pieces comprise 0.1% to 1% by weight of an antioxidant, and from 50% to 99.9% by weight of oat component, wherein the oat-based pieces comprise from 2 to 16% by weight of beta-glucan, and wherein at least 50% of the beta-glucan has a molecular weight of at least 10⁶g/mol. In an embodiment, the beta-glucan content of the oat-based pieces is from 2 to 16% by weight. In another embodiment, the beta-glucan content of the oat-based pieces ranges from 7 to 16% by weight.

The molecular weight is a fundamental parameter characterizing polysaccharide and determining its rheological properties. For example, the intrinsic viscosity values of oat beta- glucan will increase with increased molecular weight. The distribution of oat beta-glucan molecular weight varies between about 0.4xl0⁶ g/mol up to about 3xl0⁶ g/mol, depending on the source of oat beta-glucan and the extraction method of beta-glucan.

Advantageously, as discussed in the examples below and as shown on Figure 1, the structure of beta-glucans is preserved in the oat-based pieces according to the present invention. Hence, it is possible to provide a food or beverage composition with a high beta- glucan content, and with a very interesting texture and mouthfeel.

The oat component contains beta-glucan soluble fibre, such as beta-l,3-glucan, beta- 1,6-glucan, or beta-l,4-glucan, or mixture thereof. Oat is an inexpensive source of beta- glucan, but extraction of beta-glucan from oat is very difficult and expensive. The beta-glucan content varies between different oat products. Typically, the concentration of beta-glucan in conventional oat bran products is comprised between 8 to 12% of dry weight.

Oat components have been described above in connection with the process of manufacture.

In an embodiment, the oat-based pieces comprise at least 55 wt%, or at least 60 wt%, or at least 65 wt%, or at least 75 wt%, or at least 80 wt%, or at least 85 wt%, of an oat component. In an embodiment, the oat-based pieces comprise up to 99.9 wt%, or up to 99.5 wt%, or up to 99 wt%, or up to 98 wt%, or up to 97 wt%, or up to 96 wt%, or up to 95 wt%, or up to 90 wt% of an oat component. For instance, the oat-based pieces comprise from 50 wt% to 99.9 wt% of an oat component, such as from 55 wt% to 99.5 wt% of oat, or 60 wt% to 99 wt% of an oat component.

Oat-based pieces also comprise 0.1% to 2% by weight of an antioxidant as described above.

As already mentioned, in addition to the oat component and the antioxidant, the oat- based pieces may comprise other ingredients such as cereal flour other than oat, vegetable powder, fruit powder, legume flour, milk powder, sweetener, colorant, vitamins, minerals.. These ingredients were described previously.

In an embodiment, the oat-based pieces have a degree of starch gelatinisation greater than 66%. In another embodiment the degree of gelatinisation is from 66% to 98%, or from 70% to 97%, or from 80% to 96%, or from 85 to 95%. In yet another embodiment, the gelatinisation degree is from 66% to 95%, or from 70% to 90%, or from 80% to 90%. The degree of gelatinisation indicates the degree of cooking of the product. Typically, the degree of gelatinisation achieved in rolled oat flakes is below 50%. If the degree of gelatinisation is too low the starch may be less digestible and may trigger digestion discomfort. I mporta ntly, the degree of gelatinisation of the oat-pieces of the present invention must be less than 100% in order to avoid complete dissolution of the pieces when reconstituted in liquid and thereby preservation of the shape of the pieces in the reconstituted final product.

The degree of gelatinisation is determined using enzymatic reactions and is expressed as the ratio between gelatinized starch and total carbohydrates. To determine the total carbohydrates contained in the product, sample of the product to be analysed is first cooked at 95°C for at least one hour in the presence of alpha-amylase from Bacillus globigii (Sigma Aldrich A3403). Thereafter, the product is filtered. Amyloglucosidasefrom Aspergillus niger (Sigma Aldrich A7095) is added to the sample and the reaction is done at 37°C for 30 minutes, allowing thereby the total carbohydrates being converted in glucose. The sample is then filtered. The gelatinized starch is determined by reacting the sample with amyloglucosidase from Aspergillus niger (Sigma Aldrich A7095) at 37°C for 30 minutes. The gelatinized starch is thereby converted into glucose. The sample is then filtered. To measure the content in glucose in both cases, the sample is first reacted with hexokinase and glucose-6-phosphate dehydrogenase using the kit from Boehringer Mannheim/R-Biopharm and then finally glucose is measured at 340 nm with a DU 720 UV spectrometer (Beckman Coulter). A glucose solution of 0.5 g/l is used as a standard.

I n an embodiment, the oat-based pieces have a water activity Aw ranging from 0.1 to 0.5. If the water activity is loo low (e.g. below 0.1) or too high (e.g. above 0.5), the risk of oxidation and rancidity during shelf life increases. Preferably, the water activity of the oat- based pieces ranges from 0.1 to 0.4; more preferably, the water activity of the oat-based pieces ranges from 0.1 to 0.3, even more preferably from 0.1 to 0.25.

In an embodiment, the oat-based pieces have a shelf-life of 6 to 12 months at ambient temperature (usually between 20°C and 23°C). I n oat-based products, shelf life is mainly assessed by measuring rancidity of the products. For exam ple, the oxidation reaction due to endogenous lipase can produce an undesired bitter off-taste. Rancidity correlates with an increase of the pentane concentration and a decrease of the oxygen concentration, in the headspace of a packaging. Penta ne is a degradation product which results from oxidation of free fatty-acids. Hence, the oxidation of the fat com ponents can be monitored by measuring the pentane concentration. The presence of pentane indicates therefore a beginning of oxidation while the decrease of oxygen indicates a consumption of oxygen resulting from oxidation. The shelf-life of the oat products was determined by performing accelerated shelf-life tests. To perform this test, about 50 g of the products are placed in sealed cans of about 1 L. The products are then either stored at 37°C with 70% relative humidity for several months (accelerated shelf-life conditions which can be correlated to shelf-life at ambient temperature) or at 4°C to be used as references. At regular intervals (i.e. after 1 month, 2 months, 3 months, etc.), the quantities of pentane and oxygen are measured in the headspace as indicator of development of rancidity. Pentane can be measured by common analytical method such as gas chromatography with flame ionization detection (GC-FID). An FID commonly uses a hydrogen/air flame into which the sample is passed to oxidise organic molecules and produces electrically charged particles (ions). The ions are collected and produce an electrical signal which is then measured. The GC-Clarus 500™ with a FID detector from Perkin Elmer was used to measure pentane. The oxygen was measured using a Servomex oxymeter.

It is also possible to assess shelf-life with a sensory panel. Indeed, trained humans can be very sensitive to rancid flavour or smells.

With the present invention, we are able to produce oat-based pieces with an extended shelf-life when compared with traditional rolled oat flakes. Indeed, the shelf-life of traditiona l oat products is commonly 4 to 6 months, while the shelf-life of the oat-based pieces according to the present invention extends up to 9 to 12 months.

An advantage of the oat-based pieces is that they retain their overall shape after rehydration in a liquid, such as cold, ambient or warm water or milk. Due to water absorption, the oat-based pieces could swell. However, contrary to some extruded products, the oat- based pieces of the present invention do not disintegrate in liquid after rehydration. I n addition, the oat-based pieces remain as individual pieces. They do not form a thick lump once rehydrated. The shape of the oat-based pieces depends on the extrusion die. For instance, the shape of the oat-based pieces is selected from heart, star, animal, letters and numbers, or geometric figures. For instance, heart-shaped oat-based pieces were developed having a size from 3 mm to 8 mm.

A third aspect of the invention is a composition comprising oat-based pieces, as described above, together with at least one ingredient selected from sugar, fruit pieces, vegetable pieces, nut pieces, meat pieces, fish pieces, milk-based powder, aroma, and mixes thereof. Such compositions may be food compositions or beverage compositions, which may be reconstituted as food or beverage (oat pieces are milled), with liquid such as milk or water. In an embodiment, the composition comprises from 70 wt% to 95 wt% of oat-based pieces, preferably from 80 wt% to 90 wt% of oat-based pieces. Preferably for beverage compositions, oat-based pieces are comminuted. In food compositions, the oat-based pieces may be comminuted or non-comminuted.

Examples of food compositions include instant food, sweet porridge, savoury porridge, a soup, or a congee-like product. Examples of beverage compositions include instant beverage, grainy beverage, or a smoothie.

In some embodiments, the oat-based pieces can be reconstituted in warm or cold liquid to be consumed as a porridge, which can be either sweet or savoury, or a soup. In another embodiment, the oat-based pieces can be milled into smaller particles and mixed with cold or warm liquid to be consumed as a beverage. In still additional embodiments, the oat- based pieces can be consumed as snacks or moulded snacks that can be sintered or not. In yet another embodiment, the oat-based pieces can be milled, the resulting particles can be mixed with liquid to form a dough that can thereafter shaped and consumed as a vegetarian burger.

Another embodiment of the invention is a composition comprising milled oat pieces as described above, together with savoury ingredients like beans flour, spices and herbs to produce a Veggie burger type of food, reconstituted as hamburger shaped-dough to be cooked in a pan.

At last an embodiment of the invention is a composition with these milled oat pieces with nuts, milk powder and sugars to produce by sintering technology , oat snack in round shape or tablet shape (as chocolate tablet).

EXAMPLES

Examples 1: Extruded oat pieces

Oat-based pieces are prepared by extrusion, with the recipes from Table 1, under extrusion conditions mentioned in Table 2 and with the screw configuration mentioned in Table 3.

The process is the following: dry powder ingredients are dry mixed in a batch mixer. The mix is fed into the hopper of a twin-screw extruder CLEXTRAL BC 45, via a K-TRON gravimetric feeder. The extruder is composed of 4 or 6 barrels, with the screw configuration showed below in Table 3. The length of the extruder is L = 800 to 1200mm, with a L/D ratio of 14.4 to 21.6 (L: screw length; D: screw diameter). Water is added in the first barrel. The ingredients are mixed into a dough in the extruder. The dough is then extruded through a die and cut into pieces directly on the die. The die has 4 heart-shaped or round holes (maximum diameter: 2 mm).

Other vegetable powders could be used instead of carrot powder, such as spinach, zucchini, green peas, beet, or tomato.

Table 1. Dry mix recipes

The extruder was configured to have a total length of 800 mm consisting of four barrel elements. Each barrel element has a length of 200 mm and is heated at the temperatures described in Table 2. Within the total length of the extruder, a screw profile consisting of the screw elements described in Table 3 was used.

During extrusion, the dough expands slightly. The pieces are then dried to a water content of about 3% humidity on a fluid bed drier. The pieces are cooled during a resting time to ambient temperature (e.g. 20°C).

Oat-based pieces were prepared by combining recipes 1 to 6 with extrusion conditions A and B. The gelatinisation degree of cooked-extruded oat-based pieces was from 80 to 98% on average. Standard pouches were filled with the oat-based pieces for shelf-life evaluation. The shelf-life was evaluated by a trained sensory panel and by measuring the pentane content in the pouches, using common analytical method as described above. Table2. Extrusion parameters

Table 3 - Screw profile/configuration

The oat-based pieces had a shelf-life of 6 to 12 months at 20 °C, based on an accelerated shelf-life tests (performed at 37°C with 70% relative humidity).

Other trials were performed with similar extruder conditions as described in Tables 2 and 3, except that 15 parts by weight or 25 parts by weight of water were used for 100 parts by weight of dry mix. Oat pieces obtained with these conditions were acceptable. Oat pieces obtained with 15 parts by weight of water were more expanded than when using more water. On the other hand, when using above 25 parts by weight of water, the dough has a tendency to stick to the knife-cutter.

Example 2: Powdered oat beverage

Oat pieces are prepared using recipe 3 (Table 1) with extrusion conditions A (Table 2) from example 1. The dried oat pieces are then milled using a milling sieve of 0.4 mm. A powdered beverage is prepared as follows by dry-mixing:

- milled oat powder 30 parts by weight

- sugar 4 parts by weight

- strawberry flavour 1 part by weight

17.5 g of the dry mix are packed into food-grade pouches.

A sweet oat drink can be prepared by pouring the content of a pouch into 150mL of warm milk (e.g. about 80°C). It has been found that the warmer the milk the quicker the reconstitution is.

Alternatively, a cold beverage can also be prepared by mixing the pouch content with the 150mL of cold water or cold milk (e.g. at about 4-7°C or at ambient temperature).

The beverage can be reconstituted either using a blender or directly in a glass for instance.

The beta-glucan content of this powdered oat beverage made with oat pieces based on recipe 3 is about 0.5 g beta-glucan per serving (i.e. 17.5 g), which represents a beta-glucan content of 2.9 g/100 g.

Example 3: Sweet oat porridge

Oat pieces are prepared using recipe 2 (Tablel) with extrusion conditions B (Table 2) from example 1. The dried oat pieces have a size from 3 to 5 mm. A dry porridge mix is prepared by dry-mixing the ingredients shown below:

- Extruded oat pieces 82.7 wt%

- Sugar 15 wt%

- Salt 0.1 wt%

- Vanillin 0.2 wt%

- Dried apple pieces 2 wt%

40 g of the dry mix are packed into food-grade pouches. A sweet porridge can be prepared by pouring the content of a pouch into 140mL of warm milk (e.g. about 80°C). The porridge is reconstituted within 2 to 3 minutes, showing intact soft pieces with a pleasant texture. Most of the liquid is absorbed by the oat pieces. The oat pieces retain their shape, expanding a bit due to water absorption, but they do not disaggregate. The porridge does not have a gluey texture, contrary to traditional porridge made with rolled-oat flakes. Also, the porridge retains a rather soft texture, making it easy to consume with a spoon.

The beta-glucan content of this sweet oat porridge made with oat pieces based on recipe 2is about 0.9 g beta-glucan per serving (i.e. 40 g), which represents a beta-glucan content of 2.3 g/100 g.

Example 4: Sweet oat porridge enriched with oat beta-glucan

Oat pieces are prepared using recipe 6 (Table 1) with extrusion conditions B (Table 2) from example 1. The dried oat pieces have a size from 3 to 5 mm. A dry porridge mix is prepared by dry-mixing the ingredients shown below:

- Extruded oat pieces 82.7 wt%

- Sugar 15 wt%

- Salt 0.1 wt%

- Vanillin 0.2 wt%

- Dried apple pieces 2 wt%

40 g of the dry mix are packed into food-grade pouches.

The extruded oat pieces contain 7.6 g beta-glucan/100 g. A 40 g serving of this sweet porridge enriched with oat beta-glucan and made with oat pieces based on recipe 6 contains about 2.5 g of beta-glucan.

A sweet porridge can be prepared by pouring the content of a pouch into 140 mL of warm milk (e.g. about 80°C). The porridge is reconstituted within 2 to 3 minutes, showing intact soft pieces with a pleasant texture. Most of the liquid is absorbed by the oat pieces. The oat pieces retain their shape, expanding a bit due to water absorption, but they do not disaggregate. The porridge does not have a gluey texture, contrary to traditional porridge made with rolled-oat flakes. Also, the porridge retains a rather soft texture, making it easy to consume with a spoon. Example 5: Savoury oat porridge

Oat pieces are prepared using recipe 1 (Table 1) with extrusion conditions B (Table 2) from example 1. The dried oat pieces have a size from 3 to 5 mm. A dry porridge mix is prepared by dry-mixing the ingredients shown below:

- Extruded oat pieces 81 wt%

- Salt 0.5 wt%

- Chicken flavour 0.5 wt%

- Maltodextrin 10 wt%

- Freeze dried mushroom 4 wt%

- Freeze dried peas 2 wt%

- Freeze dried onion pieces 2 wt%

40 g of the dry mix are packed into food-grade pouches.

A savoury porridge can be prepared by pouring the content of a pouch into 140mL of boiling water. The porridge is reconstituted within 2 to 3 minutes, showing intact soft pieces with a pleasant texture. Most of the liquid is absorbed by the oat pieces. The oat pieces retain their shape, expanding a bit due to water absorption, but they do not disaggregate. The porridge does not have a gluey texture, contrary to traditional porridge made with rolled-oat flakes. Also, the porridge retains a rather soft texture, making it easy to consume with a spoon.

Alternatively, oat pieces prepared using recipe 5 (Table 1) with extrusion conditions B (Table 2) from example 1, can be used, instead of, or in combination with, the example described above. In addition to the pleasant texture, such a savoury porridge also has a pleasant colour.

The beta-glucan content of this savoury oat porridge made with oat pieces based on recipe 1 is about 0.6 g beta-glucan per serving (i.e. 40 g), which represents a beta-glucan content of 1.5 g/100 g.

Example 6: Savoury oat snack

Oat pieces are prepared using recipe 1, 2, 4 or 5 (Table 1) with extrusion conditions A (Table 2) from example 1. The dried oat pieces have a size from 5 to 10 mm. A coating mix is prepared with vegetable fat and maltodextrins (dextrose equivalent 10 to 20). The coating mix is sprayed on the oat pieces with spray gun at 60°C. Then the coated pieces are sprinkled with powdered savoury chicken flavour and dried parsley. The final recipe is: Extruded oat pieces 90 wt%

Palm kernel oil 3 wt%

Maltodextrins 5 wt%

Savoury chicken flavour 1 wt%

Parsley 1 wt%

Alternatively, other savoury ingredients can be used instead of chicken flavour or parsley, such as: savoury beef flavour, dried onion, spices, paprika pieces, tomato powder and the like.

The oat snack is packaged into 100 g pouches. It can be consumed as such, as a finger food. It could also be used as crouton on salad, in a soup or on a dish.

The beta-glucan content of this savoury oat snack with oat pieces based on recipe 1,2,4 or 5is about 3.6 g beta-glucan per serving (i.e. 100 g).

Example 7: Salad

Oat pieces are prepared using recipe 1, 2, 4 or 5 (Table 1) with extrusion conditions A

(Table 2) from example 1. The dried oat pieces have a size from 5 to 10 mm. A dry salad mix is prepared by dry-mixing the following ingredients:

- Blend of extruded oat pieces 93.5 wt%

- Freeze dried peas 2 wt%

- Freze dried onion pieces 2 wt%

- Beef flavour 2 wt%

- Salt 0.5 wt%

For instance, the blend of extruded oat pieces contains a mix of pieces based on recipes 1, 2 and/or 4 (non-flavoured pieces), with carrot-flavoured pieces (recipe 5). For instance, the blend comprises from 10 to 100 wt% of carrot-flavoured pieces, and the remainder, if any, is non-flavoured pieces. As an example, the blend comprises 100 wt% of carrot flavoured pieces, or 70 wt% of carrot flavoured pieces with 30 wt% of non-flavoured pieces (recipes 1, 2 and/or 4), or 30 wt% of carrot flavoured pieces, and 70 wt% of non-flavoured pieces. As mentioned above, other vegetables could be used in recipe 5 instead of carrot.

40 g of the dry mix are packed into food-grade pouches.

A savoury oat salad can be prepared by pouring the content of a pouch into lOOmL of boiling water. The salad is reconstituted within 2 to 3 minutes, showing intact soft pieces with a pleasant texture. Most of the liquid is absorbed by the oat pieces. The oat pieces retain their shape, expanding a bit due to water absorption, but they do not disaggregate. The salad has very pleasant mouthfeel.

The beta-glucan content of this salad made with oat pieces based on recipe 4 and 5 is about 1.28 g beta-glucan per serving (i.e. 40 g), which represents a beta-glucan content of 3.2 g/100 g.

Example 8: Grainy oat beverage

Oat pieces are prepared using recipe 4 (Table 1) with extrusion conditions A (Table 2) from example 1. The dried oat pieces are then milled using a milling sieve of 0.7mm. A powdered beverage is prepared as follows by dry-mixing:

- Milled oat powder 30 parts by weight

- Sugar 4 parts by weight

- Strawberry flavour 1 part by weight

17.5 g of the dry mix are packed into food-grade pouches.

A sweet grainy oat drink can be prepared by pouring the content of a pouch into l50mL of warm milk (e.g. about 80°C). It has been found that the warmer the milk the quicker the reconstitution is.

Alternatively, a cold beverage can also be prepared by mixing the pouch content with the 150mL of cold water or cold milk.

The beverage can be reconstituted in a blender or a glass for instance.

The drink has a slightly grainy texture.

The beta-glucan content of the drink made with oat pieces based on recipe 4 is about 0.5 g beta-glucan per serving (i.e. 17.5 g), which represents a beta-glucan content of 2.9 g/100 g.

Example 9: Savoury oat soup

Oat pieces are prepared using recipe 1 or 4 (Table 1) with extrusion conditions B (Table 2) from example 1. The dried oat pieces have a size of from 3 to 5 mm. A dry soup mix is prepared by dry-mixing the ingredients shown below:

- Extruded oat pieces 90 wt%

- Salt l wt%

- Chicken flavour l wt%

- Freeze-dried vegetables: mushroom: 4 wt%; peas: 2 wt%; onion pieces: 2 wt% 40 g of the dry mix are packed into food-grade pouches.

A hearty oat soup can be prepared by pouring the content of a pouch into 200mL of boiling water. The soup is reconstituted within 2 to 3 minutes, showing intact soft pieces with a pleasant texture. Most of the liquid is absorbed by the oat pieces. The oat pieces retain their shape, expanding a bit due to water absorption, but they do not disaggregate. The soup has very pleasant mouth feel.

The beta-glucan content of this savoury oat soup made with oat pieces based on recipe 1 or 4is about 1.4 g beta-glucan per serving (i.e. 40 g), which represents a beta-glucan content of 3.5 g/lOOg.

Example 10: Oat tablet

Oat pieces are prepared using recipe 4 (Table 1) with extrusion conditions A (Table 2) from example 1. The dried oat pieces are then milled to a size between 0.1 to 3 mm.

A dry mix is prepared by dry-mixing the ingredients shown below:

- Extruded milled oat pieces 62 wt%

- Sintering sugar base agent 28 wt%

- Hazelnut paste 10 wt%

The dry mix is poured into a mould, for instance having the shape of a chocolate tablet. The mix is then cooked at 140°C for 5 minutes to allow sintering of the ingredients.

The beta-glucan content in this oat tablet made with oat pieces based on recipe 4 is about 2.45 g/100 g beta-glucan.

Example 11: Veggie burger

Oat pieces are prepared using recipe 4 (Table 1) with extrusion conditions B (Table 2) from example 1. The dried oat pieces are milled between 0.1 to 3 mm sizes.

A pre-dry mix is prepared by dry-mixing the ingredients shown below:

- Extruded milled oat pieces 65 wt%

- Onion power 17 wt%

- Leek dried pieces 13 wt%

- Salt 2 wt%

- Flavors and spices 3 wt%

All ingredients are dry mixed. Then 50 gr of this dry mix is mixed with 50 ml of cold milk. This wet dough is shaped as a burger and cooked in a pan for few minutes. The beta-glucan content of this veggie burger made with oat pieces based on recipe 4 is about 1.29 g beta-glucan per 100 g.

Example 12: Extruded oat pieces with inulin

A process as described in example 1 was used to manufacture extruded oat pieces containing inulin, under extrusion conditions mentioned in Table 4 and with the screw configuration mentioned in Table 5. The recipe of the dry mix was the following:

- Oat flour 73.3 wt%

- Tocopherol 0.1 wt%

- Dipotassium phosphate 0.3 wt%

- Calcium carbonate 0.3 wt%

- Vanilla flavor 0.1 wt%

- Raftiline GR (89 wt% of inulin) 25.9 wt%

The extruder was configured to have a total length of 1200 mm consisting of six barrel elements. Each barrel element has a length of 200 mm and is heated at the temperatures described in Table 4. Within the total length of the extruder, a screw profile consisting of the screw elements described in Table 5 was used.

The extruded oat pieces contain 25.9 g fibres per 100 g, of which 2.9 g of beta-glucan and 23 g of inulin.

The extruded oat pieces could be used in the preparation of sweet food compositions similar to those of Examples 2 to 4. By replacing the vanilla flavour with savoury flavour, or by adding vegetable powder, it is also possible to use extruded oat pieces enriched with inulin in the preparation of savoury food compositions similar to those of examples 5 to 11. Table 4. Extrusion process parameters

Table 5 - Screw profile

Example 13: Beta-glucan size in extruded oat products

Oat pieces are prepared using recipe 4 (Table 1) with extrusion conditions B (Table 2) from example 1. The beta-glucan content was measured in these oat pieces, as well as in the oat flour used to manufacture the oat pieces. The molecular weight of the water-extractable beta-glucan (soluble fraction) was also measured. The molecular weight is correlated positively to the polymerisation degree of the beta-glucan.

Molecular weight of beta-glucan was measured as followed. First, dry sample to be analysed were diluted in ethanol 50% heated at 99°C for 15 minutes to inactivate endogenous enzymes. Supernatant was discarded and the sample was digested during 4 hours at 99°C under constant shaking with an alpha-amylase (Thermamyl™ from Novozymes) diluted in 0.28 mg/ml CaCI2 solution (0.25% enzyme solution) to extract beta-glucans. Supernatant was analysed by size-exclusion chromatography with specific calcofluor detection.

As shown in Figure 1, the extrusion parameters and conditions have very limited impact or no impact on the integrity of water-extractable beta- glucan in the final product. Indeed, the molecular weight of beta-glucan in the finished (i.e. extruded) product is similar to the molecular weight of water-extractable beta-glucan in the oat flour before extrusion.

Although preferred embodiments have been disclosed in the description with reference to specific examples, it will be recognised that the invention is not limited to the preferred embodiments. Various modifications may become apparent to those of ordinary skill in the art and may be acquired from practice of the invention. It will be understood that the materials used and the chemical details may be slightly different or modified from the descriptions without departing from the methods and compositions disclosed and taught by the present invention.

Claims

1. A process for manufacturing oat-based pieces, said process comprising the steps of:

b) injecting water into the cooker-extruder, in a proportion ranging from 10 to 25 parts by weight of water per 100 parts by weight of dry mix, preferably from 12 to 25 parts by weight of water per 100 parts by weight of dry mix, to obtain a dough,

c) cooking the dough downstream of water injection at a barrel temperature above 120°C, d) extruding the dough at a specific mechanical energy of 40 to 135 W.h/kg of dry mix, preferably 60 to 135 W.h/kg of dry mix, and at a flow of 2.5 to 10 kg/h/mm² of dry mix and of die surface,

2. A process according to claim 1, wherein said dry mix further comprises from 2.5% to 15% by weight of added beta-glucan.

3. A process according to claim 1 or 2, wherein said dry mix further comprises from 5% to 25% by weight of inulin.

4. A process according to any one of claims 1 to 3, wherein the expanded pieces are dried to a water-content of 3% to 4% by weight.

5. A process according to any one of claims 1 to 4, which comprises a step of coating the oat-based pieces.

6. A process according to any one of claims 1 to 5, which comprises a step of comminution of the oat-based pieces to an average size ranging from 0.1 to 3 mm.

7. A process according to any one of claims 1 to 6, wherein the dry mix further comprises at least one ingredient selected from cereal flour other than oat, vegetable powder, fruit powder, legume flour, milk powder, sweetener, colorant, soluble or insoluble fibres, vitamins, minerals.

8. A product consisting of cooked-extruded oat-based pieces, wherein said oat- based pieces comprise 0.1% to 1% by weight of an antioxidant, up to 25% by weight of inulin, and from 50% to 99.9% by weight of oat component, wherein the product comprises from 2 to 16 % by weight of beta-glucan, and at least 50% of the beta-glucan has a molecular weight of at least 10⁶ g/mol.

9. A product according to claim 8, wherein said oat-based pieces have a degree of gelatinisation greater than 66%.

10. A product according to claim 8 or 9, wherein said oat-based pieces have a water activity Aw ranging from 0.1 to 0.5.

11. A product according to any one of claims 8 to 10, wherein said oat-based pieces retain their overall shape after rehydration in a liquid.

12. A product according to any one of claims 8 to 11, wherein the oat-based pieces further comprise up to 1% by weight of calcium carbonate.

13. A product according to any one of claims 8 to 12, wherein the dry mix further comprises at least one ingredient selected from cereal flour other than oat, vegetable powder, fruit powder, legume flour, milk powder, sweetener, colorant, soluble or insoluble fibres, vitamins, minerals.

14. A product according to any one of claims 8 to 13, which comprises:

Oat component 50 to 99.9 wt%

Added beta-glucan up to 15 wt%, preferably 2.5 to 15 wt% Non-oat cereal up to 49.9 wt%, preferably 10 to 49 wt%, preferably as a cereal flour

Fruit or vegetable up to 49.9 wt%, preferably 5 to 30 wt%, preferably as fruit or vegetable powder

Milk up to 49.9 wt%, preferably 5 to 40 wt%, preferably as a powder

Sweetener up to 15 wt%, preferably 3 to 15 wt% of sugar, or the amount of sweetener or sugar substitute sufficient to provide an equivalent sweetness perception

Calcium carbonate up to 1 wt%, preferably 0.1 to 0.9 wt%

15. A product according to any one of claims 8 to 14, which is obtainable by a process according to any one of claims 1 to 7.

16. A composition comprising the product according to any one of claims 8 to 15, and at least one ingredient selected from sugar, fruit pieces, vegetable pieces, nut pieces, meat pieces, fish pieces, milk-based powder, aroma, and mixes thereof.