EP3091853A1 - Method for manufacturing puffed hollow snacks - Google Patents

Abstract

The present invention relates to a novel process for a preparing a puffed hollow snack product, more particularly to a process for preparing a light puffed hollow snack having unique properties. The present invention also relates to the novel puffed hollow snack product obtainable by the process of the invention. The process comprises the steps of (a) mixing a composition including at least 20 wt.% starch ingredient, (b) adding water to increase the total moisture content of the mixture to 25-45 wt.%, (c) extruding the mixture at 5-70 deg C and 50-90 bar, (d) cutting the extruded mixture into pieces and (e) heating in an oven.

Description

Method for manufacturing puffed hollow snacks Technical Field

The present invention relates to a novel process for preparing a puffed hollow snack product, more particularly to a process for preparing a light puffed hollow snack having resistance to breaking and/or deformation. The present invention also relates to the novel puffed hollow snack product obtainable by the process of the invention.

Background Art

The food products which are sold in the general category of snack items are many and varied, typically including such things as chips (e.g potato chips) and puffs (e.g corn puffs). Consumers generally choose snacks which have some sort of special appeal. Factors such as taste, texture and appearance are crucial to the success of a particular snack item. There is thus a great deal of creative effort from manufacturers of snack products directed toward making new snack products which have some distinctive aspect.

Many puffed snack products are currently on the market; examples of such products are represented by the followings: Crispy Chips (OSEM), Nishnushim and Doritos Menupach.

For many applications, it is advantageous to provide puffed foods with a low density and thin shell in order to provide lightness to the puffed food, which is, of course, attractive to the consuming public.The production of light snacks is highly desirable to consumers for indulgence and more healthy light snacking both for confectionery and savoury.

Light puffed snacks are anyway often associated with an intrinsic fragility which causes them to break or deform when stored or transported in flexible packaging. Accordingly there is still a need to provide puffed hollow snacks which, despite having low density and being characterised by a thin shell, show resistance to breakage and/or deformation when packed.

It is well known in the art that most puffed snacks are made from starch passed through an extruder. A screw inside a long barrel mixes, compresses and cooks simultaneously via friction and by the time the screw reaches the die at the end of the barrel the product mixture is under high temperature usually over 100°C and pressures usually over 100 bars. When the product is then exited through the die at the end of the barrel this pressure is released and water boils off very rapidly causing puffing and drying of the extruded snack product. US 3 925 563 discloses a method for preparing a puffed snack using a conventional collet extrusion equipment. According to the method described therein the expansion of the extrudate occurs upon extrusion under high temperature and pressure.

US 5 690 982 discloses a method for making a baked potato snack that produces a flat chip like product.

US 5 165 950 discloses a process wherein the product is expanded after extrusion using a microwave oven. According to the process described therein the extrusions' steps reach temperatures above 100 degrees Celsius.

US 2007/0172559 A1 , WO 03/092414 A1 disclose application of ultrasonic technology to extrusion processes.

WO 2012/173629 A1 discloses gas assisted expanded puffed products using a co- extrusion die.

Accordingly there is still also a need to identify a process for the preparation of light puffed hollow snacks which could be easily and conveniently applied in industry, for example by use of standard equipments and avoidance of high temperatures during extrusion process.

In particular, there is still a need to identify such an advantageous process which would be able to deliver light puffed hollow snacks showing resistance to breakage and/or deformation when packed.

Summary of Invention

The present invention provides a process for making a puffed hollow snack product comprising the steps of dry-mixing a composition including at least one starch based ingredient, adding water to produce a dough mixture, working said dough mixture in an extruder, cutting the extruded mixture into pieces and heating said pieces in an oven, to produce a substantially puffed product.

It was surprisingly found that by carrying out the extrusion process under low temperature and pressure conditions and then subsequently heat treating the products in an oven gave substantially puffed products endowed with unique texture and properties.

Without wishing to be bound by theory it is believed that the very low temperature and pressure conditions used in the extrusion phase create a unique stage of starch gelatinisation in the dough which enables said puffing during subsequent oven treatment.

It was surprisingly found that carrying out the extrusion process according to the invention produced low density and thin shelled puffed snack products. Advantageously, the low density and thin shelled products made according to the invention are also resistant to breaking and /or deformation, regardless of their light nature.

The products according to the invention, having resistance to breaking and being endowed with some rigidity, are less likely to break and/or deform in the packaging than other products already known in the art.

The present invention provides a process wherein the puffing steps happens after extrusion and not at the exit of the die as mainly taught in the prior art. According to one embodiment of the invention, substantial puffing occurs after the extrusion step is complete and during the oven step. The prior art teaches that conventionally the oven is used to dry and bake a puffed extruded product, according to the invention the heat treatment step in the oven step is causing the expansion of the extruded dough material to provide a substantially puffed hollow snack.

In conventional extrusion methods high temperatures and high pressures are employed. This is otherwise known in the art as cooked extrusion whereby puffing occurs at the die exit. The present invention provides a process wherein the extrusion step is carried out at low temperature and pressure, otherwise known in the art as cold extrusion. According to this invention the puffing occurs after the extrudate exits the die, more specifically a substantially expanded hollow product is obtained after heat treatment in an oven.

The invention also relates to the puffed hollow product obtainable according to the process of the invention upon exposure to heat treatment in an oven. Within the context of the present invention, "puffed" products are to be intended as starch based products which are expanded and inflated to become hollow by steam that occurs from water evaporation during heating stage.

Within the context of the present invention, the term "hollow" is to be intended as identifying as a product comprising one large cavity surrounded by a shell having walls comprising small cells. Fig 7 provides a schematic representation of the snacks according to the present invention and of associated structural features.

According to a first aspect of the present invention there is provided a process for the production of a puffed hollow snack product comprising the steps of a) mixing a dry starch composition including at least 20% by weight, based upon the weight of the dry-mix, of at least one starch based ingredient; b) adding water to raise the total moisture content of the mixture to a value comprised between 15 to and 60% by weight; c) working the mixture in an extruder and extruding the said mixture; d) cutting the extruded mixture into pieces and; e) heating in oven to produce a substantially puffed hollow snack product.

According to the invention the process involves a puffing step wherein said puffing to produce a substantially puffed product occurs during step e).

In one embodiment, step e) is carried out at a temperature comprised between 160 and 190 degrees C.

In one embodiment the process involves the working and extrusion of the mixture wherein said working and extrusion is carried out under low temperature and pressure. In one embodiment, the working and extrusion temperature is comprised between 5 and 70 deg C, preferably between 10 and 60 deg C, preferably between 10 and 55 deg C. In one embodiment, the working and extruding pressure is comprised between 50 and 90 bar, preferably between 60 and 85 bar.

In further embodiments of the present invention the process further comprises frying or coating the puffed hollow snack or any combinations thereof. In one embodiment, the substantially puffed product obtained in step e) is fried in fat and optionally coated.

In another embodiment, the substantially puffed product obtained in step e) is cooled and subsequently optionally coated.

In one embodiment, the oven used in step e) is an electric oven.

In another aspect of the present invention, a puffed hollow snack product is provided.

In one embodiment, the puffed hollow snack product has shell thickness comprised between 0.2 to 0.9 mm. In another embodiment, the puffed hollow snack product has a density comprised between 0.05 to 0.12 g/mL. In a preferred embodiment, the puffed hollow snack product has shell thickness comprised between 0.2 to 0.9 mm and density comprised between 0.05 to 0.12 g/mL.

A puffed hollow snack product according to the present invention is obtainable by a process according to the invention.

Additional features are described herein and will be apparent from the following detailed description and the figures.

Brief Description of the Figures

Figure 1 , is the X-ray tomography images of shells of samples obtained as described in Example 4.

Figure 2 is X-ray tomography images of shells of samples obtained as described in Example 2.

Figure 3 is X-ray tomography images of shells of samples obtained as described in Example 3 (after removal of chocolate coating).

Figure 4 are X-ray tomography images of shells of samples obtained as described in Example 1 .

Figure 5, 6 are X-ray tomography images of shells of competitor samples , namely Crispy Chips (OSEM) and Nishnushim. Figure 7 is a schematic representation of the structure of an hollow product according to the present invention as it may appear following a transversal cut.

Detailed description of the preferred embodiments

According to the invention the "starch based ingredient" includes any ingredient containing starch such as any commercially available or modified cereal, root or leguminous starch, partially or completely gelatinized starch, dried or dehydrated potato product including potato flour, potato granules and potato flakes, corn flour, corn meal, buckwheat flour, rice flour, barley flour, tapioca and any combinations thereof.

Alternative embodiments of the starch ingredient includes a gluten-containing starch ingredient such as wheat flour, rye flour, sorghum flour, gram flour and any combinations thereof. In preferred embodiments the starch based ingredient is white flour, more preferably hard wheat white flour.

According to another embodiment of the invention the starch based ingredient is preferably potato starch. In another embodiment of the invention the starch based ingredient is potato flakes or granules.

An embodiment of the method of this invention uses starch ingredients that are mixtures of hard wheat white flour and potato starch or potato flakes or potato granules.

The dry-starch mix composition typically comprises 20 to 100 percent by weight of starch based ingredient , preferably 50 to 100% by weight, based on the weight of the dry-mix.

Other ingredients may be included in the dry starch mix composition. For example, sweetening agents may be added to provide flavour as well as texture. Suitable sweetening agents include those well known in the food industry e.g. natural sweeteners such as sugars and synthetic sweeteners such as aspartame or saccharine. Sucrose is a preferred sweetening agent. Generally sweetening agents are included as about 1 to 10% by weight of the dry mix, preferably from about 1 to about 8% by weight of the dry mix, more preferably from about 1 to 5% by weight of the dry mix. Other additives commonly used in the food industry such as flavouring and/or colouring agents, leavening agents (typically in an amount of 0 to 2%) may also be included in the dry mix composition.

The mix can be prepared by first mixing powdery components to obtain a dry mix. The dry mix can be fed into the extruder as it is or it can be mixed together with a liquid or fluid components prior to entering the extruder. After feeding the ingredient mix into the extruder, it can be further mixed in a first mixing section of a traditional food extruder.

The extruder can be a twin or single screw extruder, more preferably a twin screw extruder. The twin screw extruder tipically comprises at least 4 sections , each section may be regulated to ensure a certain temperature profile. In some embodiments of the invention, section 1 may have a temperature range between 17 and 20 degrees C, section 2 may have a temperature range between 1 1 and 13 degrees C, section 3 may have a temperature range between 10 and 12 degrees C and section 4 may have temperature range between 46 and 51 degrees C.

The mixture is worked in said extruder at a temperature range between 0 and 70 degrees C, preferably between 5 and 60 deg C, preferably between 10 and 60 deg C, preferably between 10 and 55 deg C.

The mixture is worked in said extruder at a pressure range between 50 and 90 bar, preferably between 60 and 85 bar.

Water (and/or steam) and/or a sugar solution and/or a fat solution can be added into the extruder. The total moisture content of the mixture is preferably between 15 to about 60% by weight , based on the weight of the dry-mix, more preferably between 25 to about 45% by weight.

The mixture is worked, compressed and sheared so that it forms a doughy mass. This said doughy mass may be cold extruded by having it pushed by an extruder screw or twin screw through the openings of a die at the end of the extruder. At the exit of the extruder the product temperature is between 10 to 70 degrees C, more preferably between 40 and 60 degrees C.

As the doughy mass is worked under low temperatures and pressures, the resulting extruded product shows no substantial puffing or expansion at the die exit. As the doughy mass having no substantial puffing or expansion when exits the extruder barrel through the extrusion die, the said mass is cut into pieces using conventional extrusion cutting means. In some embodiments a conventional pillow-crimper may be used. Other cutters that may be used include wheel cutter, horizontal and, or vertical face-cutter, embosser and crimper. A person skilled in the art would be familiar with the methods of cutting extruded material.

In one preferred embodiment, the extruded mixture is cut into pieces of different size and shape. Preferably, the pieces are cut out in oval shape. Preferably the length size of pieces which are cut out is comprised between 5 and 50 mm.

The cut pieces are fed into the puffing oven wherein the said pieces substantially expand to produce a substantially puffed hollow product. The pieces are fed into the oven at temperature between 100-250 degrees C for 30-720 seconds, more preferably at 160 to 190 degrees C for 60 to 360 seconds. In some embodiments of the invention the cut pieces are only partially puffed having been treated in the oven for a shorter period of time, preferably at a temperature comprised between 175 and 185 degrees C for 50 to 70 seconds.

In some embodiments of the invention, the substantially puffed product may be further fried in oil or fat, preferably at 180 degrees C for 30 to 60 seconds. In other embodiments, the substantially puffed product may be further coated, said coating including but not limited to fat-based coating (such as for example chocolate or chocolate-like coating), sweet coating, savoury coating, caramel coating and sugar coating. The coating may also comprise, in one embodiment of the present invention, dry particles such as, for example, bread crumbs, nuts pieces, spices etc.

In one embodiment of the invention, the mixture to be extruded may comprise coarse granular ingredients such as , for example, poppy seeds, corn grits, sesame seeds, wheat semolina, milled wheat bran etc. Coarse granular ingredients may be added in an amount up to 30% w/w of the total dry mix ingredients.

In alternative embodiments of the invention, the puffed hollow product may be substantially puffed or partially puffed and fried, and/or coated or any combinations thereof.

In a further embodiment of the invention, a puffed hollow snack product having a shell thickness between 0.2 and 0.9 mm preferably between 0.2 and 0.8 mm, preferably between 0.3 and 0.8 mm, preferably between 0.2 and 0.6 mm is provided.

In one embodiment of the invention a puffed hollow snack product having a density between 0.05 and 1 .2 g/mL, more preferably between 0.08 and 0.12 g/mL is provided.

In one embodiment, a puffed hollow snack having a mean wall thickness (MWT) comprised between 130 and 300 μητι, preferably between 150 and 250 μηη is provided.

In one embodiment, the puffed hollow snack product according to the invention has a shell thickness of 0.2 to 0.9 mm, a density of 0.05 to 0.12 g/mL and a mean wall thickness (MWT) comprised between 130 and 300 μητι, preferably comprised between 150 and 250 μηη.

In a preferred embodiment, the process includes the steps of mixing wheat white flour, potato starch, sugar, calcium carbonate, and salt ; adding water to raise the total water content of the mixture; working the mixture in an extruder and extruding said mixture; cutting the extruded mixture into pieces; heating in an oven to produce a substantially puffed product; frying said puffed product in fat and coating the puffed product wherein said coating includes a chocolate or sweet, or savoury or caramel, or sugar syrup or sugar powder or any combinations thereof.

In another preferred embodiment the process includes the steps of mixing wheat white flour, potato starch, sugar, calcium carbonate and salt; adding water to raise the total water content of the mixture; working the mixture in an extruder and extruding said mixture; cutting the extruded mixture into pieces; heating in an oven to produce a substantially puffed product; cooling said puffed product and coating the puffed product wherein said coating includes a chocolate or sweet, or savoury or caramel, or sugar syrup or sugar powder or any combinations thereof.

In one embodiment of the process of the invention, extruded dough which is left over after cutting the required product shape may be chopped or milled, or chopped/milled and blended with water or dried in the oven and chopped/milled to a fine powder to be reintroduced in the composition to be extruded as part of the wet or dry ingredients respectively for example in an amount ranging from 0 to 50%w/w, preferably from 0 to 30% w/w.

According to the present invention the puffed hollow snack products possess unique attributes such as being more resistant to breaking and more rigid, i.e. more resistant to deformation. These attributes are measured by carrying out mechanical tests such as breaking force test and elastic modulus test respectively as better detailed in the experimental section below reported.

The puffed hollow snacks according to the present invention are on average lighter of analogous products already known in the state of the art.

The main attributes of the structure of the puffed hollow snacks of the invention are those of the shell surrounding the hollow cavity.

These comprise: density, porosity, shell thickness, wall thickness, i.e. thickness of the walls between pores contained in said shell, pore size, i.e. dimensions of the pores contained in said shell.

The preferred puffed hollow snack products have a porosity between 15 and 50%, more preferably 20 and 35%, wherein the said porosity is the porosity of the shell as below defined. The preferred hollow snack products having average pore sizes above 1 10 microns, preferably between 120 and 300 microns, more preferably between 130 and 250 microns.

The preferred hollow puffed snack products have an average wall thickness of between 130 and 250 microns, preferably between 150 and 250 microns;

The preferred puffed snack products have a breaking force between 3 and 16 N, preferably between 10 and 15 N. The preferred puffed snack products have an initial slope of force displacement between 15 and 40 N/mm or 20 and 35 N/mm.

In one embodiment of the invention, the preferred snack products have a unique structural texture having a density between 0.05 and 0.12 g/mL and shell thickness between 0.2 and 0.9 mm and shell porosity between 15 and 50% and an average wall thickness of shell being above 150 microns. Further embodiments of the invention include any combinations thereof.

Experimental Section Determination of the density of the products

The density was measured using a cylindrical cup with a known volume, by filling the cup with free flowing product until reaching the top of the cup, without compressing the content of the cup, and weighing the weight of the material that was inserted. The weight in grams is divided by the volume in ml resulting with the density measurement expressed in g/ml

Determination of product shell wall thickness

The product shell wall thickness was measured using an Electronic Comparator from Standard Gage Hexagon Metrology by measuring the walls of three samples that are broken open, wherein this involves separating the walls from each other and making an average of the readings.

Determination of the mechanical properties of the product (Breaking Force and Initial Slope of the force displacement)

Mechanical properties of the products were measured with a Texture Analyzer TA.HDI (from Stable Micro Systems) equipped with a 50N load cell. A 2 mm diameter cylinder probe was used to compress and crush one product in the center of the curved surface. The crosshead speed was 1 mm/s across a displacement of 5 mm. Ten replicates were performed for each sample.

From the force-displacement curves, different values were extracted: (i) breaking force (N), corresponding to the force at which the breaking of the cereal matrix occurs, i.e. the maximum force (ii) the initial slope of the force-displacement (N/mm) calculated between 0 et 0.4 mm of displacement.

The breaking force characterizes the resistance to breaking, i.e. the higher the breaking force, the lower the fragility and the higher the resistance.

The initial slope characterizes the elastic modulus of the matrix, i.e. the rigidity; the higher the slope, the more rigid the matrix.

Statistical analysis was performed on the data in replicate. Analysis of variance (ANOVA) was used with a Fisher test at 95% confidence level to assess the significance of the differences. Determination of the internal structure of the products by microcomputed X- ray tomography and 3D image analysis

Images acquisition of the cereal sheii

X-ray tomography scans are performed with a 1 172 Skyscan MCT (Bruker MicroCT, Kontich, Belgium) with a X-ray beam of 80kV and 100uA. Scans are performed with the Skyscan software (version 1 .5 (build 9)A (Hamamatsu 10Mp camera), reconstruction with the Skyscan recon software (version 1 .6.3.0) and 3D image analysis with CTAn software (version 1 .10.1 .3, 64-bit).

Several pieces of cereal shell were placed in the X-ray tomography chamber. For a pixel size of 8um, the camera was set up at 2000x1048 pixels and samples were placed in the Near position. Exposure time was 295 ms. Scans were performed over 180°, the rotation step was 0.4° and the frame averaging was 8.

The reconstruction of the dataset was performed over 900 slices in average, with the settings contrast at 0.005-0.10. Smoothing and ring artefact reduction were both set up at 1 .

3D analysis of the images

3D image analysis was performed on 16 urn per pixel reduced datasets over 450 slices. The analysis was performed in two steps: (i) a first step to select the cereal area to be analysed by excluding the outer area surrounding the cereal, (ii) the second step to obtain the porosity of the cereal shell.

(i) Selection of the cereal area, i.e. volume of interest:

The images in grey levels were segmented. The segmentation was performed at a grey level of 40, and then images were dilated by mathematical morphology. The selection of the volume of interest was performed through the shrink-wrap function, and then this volume was eroded by mathematical morphology to adjust to the surface of the flakes. Dilation and erosion parameters were chosen in order to obtain the best adjustment to the surface of the particles.

(ii) 3D image analysis:

The images were reloaded and segmented at a grey level of 40. The porosity was then calculated as the ratio of the volume of voids in the cereal shell out of the cereal shell volume, the cereal shell volume being equal to the volume of interest defined above (i). The structure separation gave the pores size distribution of the cereal shell. The structure thickness gave the distribution of thickness of walls. Example 1

A flour composition as shown in Example 1 is fed into a twin screw extruder (BC45 Clextral) at a rate of 45 Kg/hr together with 14 kg/hr of water. The extruder is running at 190 rpm. The temperature profile is 17 deg C/1 1 deg C/10 deg C/51 deg C in the successive barrels of the extruder. The dough reaches a temperature of 57 deg C at the extruder die, with a material pressure of 65 bar, leading to an extruded non-puffed dough material. The extruded product is cut to round or rectangular shapes of 22 mm diameter or side and the pieces are fed into the oven at 180 deg C for 60 to 360 seconds to produce substantially puffed hollow snack products.

Example 2

A flour composition as shown in the Example 2 is fed into a twin screw extruder (BC45 Clextral) at a rate of 55 Kg/hr together with 23-26 kg/hr of water. The extruder is running at 200 rpm. The temperature profile is 19-20 deg C/12-13 deg C/1 1 -12 deg C/46-50 deg C in the successive barrels of the extruder. The dough reaches a temperature of 52-54 deg C at the extruder die, with a material pressure of 63-81 bar, leading to an extruded non-puffed dough material. The extruded product is cut to round or rectangular shapes of 22 mm diameter or side and the pieces are fed into the puffing or drying oven at 180 deg C for 60 seconds to produce a partially puffed snack products. These products are fried in oil or fat at 160 deg C for 30-90 seconds and then seasoned with salt or flavoured seasoning to produce puffed hollow products.

Example 3

Products according to Example 3 may be obtained according to the procedure above described in Example 1 where the puffed hollow products are then further dried at 180 deg C for 180 sec and then coated with milk chocolate.

Example 4

Products according to Example 4 may be obtained according to the procedure above described in Example 1 where the puffed products are then are fried in oil or fat at 180 deg C for 20 to 60 seconds to produce puffed and fried hollow snack products.

Example 5

Products according to Example 5 may be obtained according to the procedure described above in Example 1 where poppy seeds are added in an amount of 7% w/w added to the ingredient dry mix.

Example 6

Products according to Example 6 may be obtained according to the procedure above described in Example 5 where the puffed products are then are fried in oil or fat at 180 deg C for 20 to 60 seconds to produce puffed and fried hollow snack products.

Table 1 herebelow reported summarizes the structural attributes measured on the samples obtained according to the invention and on prior art products currently on the market: Table 1

'Porosity' as hereabove reported is defined as the porosity of the cereal shell and is further defined as the volume of pores divided by the volume of the cereal shell whereby the empty cavity is excluded.

'MCS'(Mean cavity size) as hereabove reported is defined as the average pore size in the cereal shell

'MWT' (Mean Wall Thickness) as hereabove reported is defined the average wall thickness, more specifically said wall thickness is defined as the thickness of the material between the pores in the cereal shell.

As it is evident form results reported in Table 1 , the puffed hollow snacks according to the present invention are on average lighter than products according to the state of the art [lower cereal shell thickness (0.4-07 vs 0.8-1 .2 urn) and lower density (0.08-0.12 vs 0.1 1 -0.16 g/mL].

Also, the puffed hollow snacks according to the invention are characterized by higher values for MCS and MWT (iim ) than the corresponding prior art products.

Without wishing to be bound by theory, it is believed that the unique structure attributes of the cereal shell for the hollow products of the invention provide them with the surprising properties in terms of resistance to breaking and deformation which have been observed and reported in Table 2 herebelow.

Table 2

Puffed hollow products according to the invention showed an higher breaking force (especially examples 4, 3 and 1 ) and an higher Initial Slope of force displacement (all the tested samples) when compared with prior art products. The measured properties are considered to be predictive of an increased resistance to breaking and deformation for the puffed hollow snack products.

Claims

Claims

1 . A process for preparing a puffed hollow snack product comprising the steps of a) mixing a composition including at least 20% by weight, based upon the weight of the dry-mix, of at least one starch based ingredient b) adding water to raise the total moisture content of the mixture to between 25-45% by weight c) working the mixture in an extruder and extruding the said mixture at a temperature comprised between 5 and 70 deg C and under a pressure comprised between 50 and 90 bar d) cutting the extruded mixture into pieces and e) heating in oven to produce a substantially puffed product.

2. The process according to claim 1 wherein the puffing to produce a substantially puffed product occurs during step e).

3. The process according to claim 1 or 2 wherein the puffing to produce a substantially puffed product during step e) is performed at 160-190 degrees C.

4. The process according to anyone of preceding claims wherein step c) is carried out at a temperature comprised between 10 and 60 deg C.

5. The process according to anyone of preceding claims wherein step c) is carried out under a pressure comprised between 63 and 81 bar.

6. The process according to anyone of preceding claims wherein at the exit of the extruder the product temperature is 50 to 60 degrees C.

7. The process according to anyone of preceding claims which further comprises a step f) of frying the puffed hollow snack product.

8. The process according to anyone of preceding claims which further comprises a step g) of coating the puffed hollow snack product.

9. A puffed hollow snack product obtainable by process according to claim 1 having a shell thickness of between 0.2 and 0.9 mm and density of between 0.05 to 0.12 g/ml_.

10. A puffed hollow snack product having shell thickness of 0.2 to 0.9 mm and density of 0.05 to 0.12 g/mL.

1 1 . A puffed snack product according to claim 10 having porosity between 15 and 50 %, preferably 20 and 35 %

12. A puffed hollow snack product according to claim 10 or 1 1 having average wall thickness above 150 microns.13. A puffed hollow snack product obtainable according to anyone of claims 10 to 12 and comprising coarse granular ingredients such as for example poppy seeds.