Process for preparing a batter

Abstract

The invention pertains to a process for preparing a batter comprising the steps of: (a) providing a starch-containing side stream of potato processing process; (b) optionally comminuting the starch-containing side stream; (c) separating starch from the starch-containing side stream to obtain a non-modified starch; (d) modifying the obtained starch to obtain a modified starch; (e) adding the modified starch and optionally the non-modified starch to a batter; and (f) optionally applying the batter to a food product, wherein the non-modified and modified starch are not gelatinized.

Description

[0001] PROCESS FOR PREPARING A BATTER

[0002] The present invention relates to a process for preparing a batter and moreover to potato food products.

[0003] Potato food products such as potato fries or French fries which comprise a coating are well known in the art. Generally, the potato fries are obtained by first steam peeling of whole potatoes, cutting the potatoes and subsequently applying a batter to cover the potato slices. The steam peel obtained by the steam peeling process generally contained gelatinized starch, which is difficult to further process and re-use in food applications. Also steam peeled potatoes generally have a cooking ring which alters the surface of the potato. There is a need to process potatoes in an environmentally more friendly way and produce greener potato food products.

[0004] There is further a need to provide a process for preparing a batter in a more environmentally friendly way and to improve the use of more of the potato for human food. In WO 97 / 42827 batter compositions for coating vegetables prior to fat frying are disclosed. These batter mixes comprise a high amount of high amylose rice flour together with starch and other additives such as salt and sodium bicarbonate. The starch may be from various plant-based sources and is generally native starch.

[0005] EP 0 898 902 describes aqueous starch enrobing slurry for coating the outer surface of a potato product, which comprises at least 50 wt% rice flour and less than 5 wt% of unmodified pre-gelled potato starch.

[0006] The objective of the present invention is to provide a novel process for preparing a batter.

[0007] The invention pertains to a process for preparing a batter comprising the steps of:

[0008] (a) providing a starch-containing side stream of potato processing process;

[0009] (b) optionally comminuting the starch-containing side stream;

[0010] (c) separating starch from the starch-containing side stream to obtain a non-modified starch;

[0011] (d) modifying the obtained starch to obtain a modified starch;

[0012] (e) adding the modified starch and optionally the non-modified starch to a batter; and

[0013] (f) optionally applying the batter to a food product, wherein the non-modified and modified starch are not gelatinized.

[0014] In step (a) of the inventive process, a starch-containing side stream of potato processing process is provided. The starch-containing side stream can be any starch-containing side stream of the potato processing process. Preferably, the starch in such side streams is native starch. Preferably, the non-modified starch is not gelatinized. Examples of such starch-containing side stream can be potato peel which is mechanically peeled, starch from potato cut side stream from cutting peeled potatoes, reject streams from mechanical and optical sorters and cut potatoes which are not according to specifications. Preferably, the starch-containing side stream is potato peel obtained from mechanical peeling. Preferably, the starch-containing side stream is an aqueous potato cut side stream. In another embodiment, the starch-containing side stream is the reject streams from mechanical and optical sorters. In another embodiment, the starch-containing side stream is cut potatoes which are not according to specifications. It is contemplated that two or more side streams are combined to a single starch-containing side stream. In one embodiment, the side streams are combined before, during or after the comminution step (b).

[0015] In one embodiment, the temperature in step (a) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C.

[0016] In optional step (b), the starch-containing side stream is comminuted. Comminution is preferred when the side stream contains potato particles or potato pieces which require comminution, for example the potato peel obtained in step(a). Comminution refers to the process of reducing the size of the potato pieces, for instance potato peel. Comminution of the potato pieces can be performed using any method known in the art. Examples of such comminution methods include cutting, meshing and grinding. Two or more comminution steps are contemplated. Comminution can be carried out without adding water and by adding water.

[0017] In one embodiment, the temperature in step (b) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (b) is the same as the temperature in step (a).

[0018] In step (c), starch is separated from the starch-containing side stream to obtain non-modified starch. Starch can be separated using any method known in the art. Examples of separation methods include filtering, cyclone separation, centrifuging and decanting. Preferably, the non-modified starch obtained in step (c) is a native starch.

[0019] In one embodiment, the temperature in step (c) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (c) is below the gelatinization temperature of the potato starch. Preferably, the temperature in step (c) is the same as the temperature in step (b).

[0020] Optionally in step (d), the non-modified starch is modified to obtain a modified starch. Such modification can be any modification known in the art. Such modifications include surface modification, introducing anionic, zwitterionic and / cationic groups and crosslinking. Preferably, the modified starch is a crosslinked starch. Crosslinking can be performed using phosphor-containing crosslinking agents such as metaphosphate. Preferably, the crosslinked starches can be suitably used in batters for potato food products such as potato fries. Preferably, the modified starch is not gelatinized.

[0021] In step (e), the modified starch obtained in step (c) and optionally the non-modified starch obtained in step (d) are added to a batter. The batter may be any batter known in the art. In one embodiment, the batter comprises at least 20 wt% starch, more preferably at least 30 wt% starch, even more preferably at least 40 wt% starch and most preferably at least 50 wt% starch, and preferably at most 100 wt% starch, more preferably at most 99 wt% starch, even more preferably at most 95 wt% starch, even more preferably at most 90 wt% starch and most preferably at most 80 wt% starch, based on the total dry weight of the batter. The amount of starch can be determined using any suitable method known in the art. Examples of a suitable method include spectrophotometric methods such as the method of NEN-EN- ISO 15914.

[0022] In one embodiment, the batter comprises at least 20 wt% modified starch, more preferably at least 30 wt% modified starch, even more preferably at least 40 wt% modified starch and most preferably at least 50 wt% modified starch, and preferably at most 100 wt% modified starch, more preferably at most 99 wt% modified starch, even more preferably at most 95 wt% modified starch, even more preferably at most 90 wt% modified starch and most preferably at most 80 wt% modified starch, based on the total dry weight of the batter. The amount of modified starch can be determined using any suitable method known in the art. It is contemplated that the batter comprises the modified starch as the sole starch component.

[0023] In one embodiment, the batter comprises at least 20 wt% non-modified starch, more preferably at least 30 wt% non-modified starch, even more preferably at least 40 wt% nonmodified starch and most preferably at least 50 wt% non-modified starch, and preferably at most 99 wt% non-modified starch, more preferably at most 95 wt% non-modified starch, even more preferably at most 90 wt% non-modified starch, even more preferably at most 85 wt% non-modified starch and most preferably at most 80 wt% non-modified starch, based on the total dry weight of the batter. The amount of modified starch can be determined using any suitable method known in the art. The non-modified starch is generally used in combination with the modified starch. Using only non-modified starch or native starch in the batter generally leads to a coated food product, preferably a potato fry, which is sticky prior to the par-frying step and leads to agglomeration of potato fries, which is undesirable.

[0024] In one embodiment, the weight ratio of the modified starch and the non-modified starch is at least 0.01 , preferably the weight ratio is at least 0.1, more preferably at least 0.2 and most preferably at least 0.5, and preferably at most 100, more preferably at most 50, even more preferably at most 20 and most preferably at most 10.

[0025] In one embodiment, the batter comprises at least 10 wt% water, based on the total weight of the first coating composition. Preferably, the batter comprises at least 20 wt% water, more preferably at least 30 wt% water, even more preferably at least 35 wt% water and most preferably at least 40 wt% water, and preferably at most 80 wt% water, more preferably at most 70 wt% water, even more preferably at most 65 wt% water and most preferably at most 60 wt% water, based on the total weight of the batter.

[0026] In one embodiment, the batter may further comprise a food-grade additive. Examples of such food-grade additives includes protein, sugars, (dietary) fibers, cross-linking agents, preservatives, flavouring agents, rheology modifiers such as xanthan and colouring agents.

[0027] In one embodiment of the invention, the batter comprises at least 1 wt% of the food-grade additive. Preferably, the batter comprises at least 2 wt% food-grade additive, more preferably at least 5 wt% food-grade additive, even more preferably at least 10 wt% foodgrade additive and most preferably at least 15 wt% food-grade additive, and preferably at most 50 wt% food-grade additive, more preferably at most 40 wt% food-grade additive and most preferably at most 30 wt% food-grade additive, based on the total weight of the batter.

[0028] The amounts of starch, food-grade additives and any other components add up to 100% by weight of the batter.

[0029] In optional step (f) of the inventive process, the batter is applied to the core of the potato food product to obtain the potato food product. The application of the batter can be performed using any method known in the art. Such application methods include submerging and spraying.

[0030] In one embodiment, the temperature in step (f) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (g) is below the gelatinization temperature of the potato starch. Preferably, the temperature in step (f) is the same as the temperature in step (b).

[0031] The invention further pertains to a product obtained with the above process for preparing a batter. In one embodiment, the product is a batter. Preferably, the product or the batter comprises a non-modified starch and / or modified starch obtained with the above process.

[0032] The invention further pertains to a potato food product comprising a core and a coating covering the core, wherein the core is obtained by mechanical peeling. With “mechanical peeling” is meant to remove the skin or outer layer of a vegetable in particular a potato. Mechanical peeling can be performed using abrasive means such as stiff brushes, carborundum rollers or revolving bowls or drums with abrasive surfaces; and non-abrasive means such as stationary knives or razor-like blades. Preferably, mechanical peeling is performed using abrasive means, more preferably using carborundum rollers. When the core of the inventive food product is obtained using mechanical peeling, the native nature of the core is intact as opposed to steam peeling which is commonly used. Steam peeling generally leads to heating of the potato surface, gelatinization of the potato periphery and subsequent drying of the surface to create a leathery surface layer also referred to as the “cooking ring”. Such a cooking ring is not formed when mechanical peeling is applied. Such a cooking ring is generally present at the outer ends in potato fries, which may take up to 10% of the total surface of the potato fries. Applying a batter or coating to the leathery surface may lead to a lower uptake and less uniform application of the coating, whereas a mechanically peeled core generally has a more uniform distribution of the batter. This generally leads to an improved crunchiness, a reduced water release and a more controlled fat uptake. Moreover, such leathery surfaces may lead to blister formation during par-frying and / or frying of potato fries.

[0033] In addition, the (mechanical) peel comprises starch in its native form, which can be isolated. The isolated starch can be used in the inventive food product in modified and / or unmodified form. The side stream from the steam peeling process comprises starch which can generally not be isolated and re-used, but instead is used in animal feed or bio-digestion. By mechanical peeling of the potatoes, over 95% of the potatoes can be used as raw materials with significantly less waste being formed. Furthermore, mechanical peeling requires less energy and (boiler) water, which reduces the environmental impact of the mechanical peeling process and consequently the whole potato fries producing process. Also, steam peeling is generally performed at a higher temperature than mechanical peeling, which may increase undesirable microbial growth. Moreover, mechanical peeling does not require safety measures for dealing with processing steam.

[0034] The inventive potato food product comprises a core which is obtained by mechanical peeling. Such mechanical peeling leads to potato food products which can be recognized per se and discriminated from steam peeled cores of conventional food products. In one embodiment, the core comprises straight and / or corner cuts at the ends of the inventive food product. In one embodiment, at least 50% of the potato food products have a core comprising straight and / or corner cuts at the ends, preferably at least 80%, more preferably at least 90% and most preferably at least 95% of the potato food products have a core comprising straight and / or corner cuts at the ends. The straight and corner cuts can be determined using light microscopy and scanning electron microscopy. It is noted that steam peeled potato food products have a core with generally a smooth and curved form at the ends of the steam peeled products.

[0035] In one embodiment of the invention, the inventive food product comprises a 1-layer structure on all sides of the food product. With “1-layer structure” is meant that in a scanning electron microscope (SEM) one layer is identified on top of the (potato) core. A steam pealed core results in a 2-layer structure at least at the outer ends of the food product, namely the leathery starch-based core periphery and the coating.

[0036] The potato food product of the invention comprises a core and a coating covering said core. With the wording “covering” is meant that the core is covered on all sides by the coating. In one embodiment, the coating may comprise air pockets or bubbles. It is noted that despite the presence of such air pockets the integrity and coverage of the coating is not negatively impacted, and fat migration to the core during frying or frying is generally impeded.

[0037] The food product of the invention comprises a core. The core is generally edible and can be any core known in the art. The core can have any shape and form known in the art such as a mash, a paste or a solid food substrate. In one embodiment, the core is potato. Preferably, the potato is a potato suitable for use in potato-based food products such as French fries and (sweet) potato wedges.

[0038] In one embodiment, the potato food product comprises at least 5 wt% core, based on the total dry weight of the potato food product. Preferably, the inventive food product comprises at least 10 wt% core, more preferably at least 20 wt% core, even more preferably at least 30 wt% core and most preferably at least 40 wt% core, and preferably at most 90 wt% core, more preferably at most 80 wt% core and most preferably at most 70 wt% core, based on the total dry weight of the food product. This value is determined by separating the coating from the core e.g. by using a knife, and weighing the core.

[0039] In one embodiment, the core comprises at least 10 wt% water, based on the total weight of the core. Preferably, the core comprises at least 20 wt% water, more preferably at least 30 wt% water, even more preferably at least 35 wt% water and most preferably at least 40 wt% water, and preferably at most 80 wt% water, more preferably at most 70 wt% water, even more preferably at most 60 wt% water and most preferably at most 50 wt% water, based on the total weight of the core. The core generally comprises a higher amount of water than the coating of the inventive food product. The coating enables a significantly lower water loss during frying or frying, which generally renders a juicier food product with an improved texture. Moreover, the food product may maintain its heat for a longer period of time.

[0040] In one embodiment, the core comprises at most 10 wt% fat, based on the total dry weight of the core. Preferably, the core comprises at most 8 wt% fat, more preferably at most 5 wt% fat, even more preferably at most 3 wt% fat and most preferably at most 2 wt% fat, and preferably at least 0.1 wt% fat, more preferably at least 0.2 wt% fat and most preferably at least 0.5 wt% fat, based on the total dry weight of the core. The total dry weight is defined as the total weight of the core without water. The amount of fat can be determined with methods known in the art including organic solvent extraction. An example of such a technique is the ISO 6492 method. A piece of the core is taken to use in the method.

[0041] The potato food product of the invention comprises a coating. The coating can be any coating known in the art and suitable for use in potato food products. Such coatings may comprise starch, modified starch, (plant-based) protein, dextrins, rheology modifiers such as xanthan, fat and other suitable additives.

[0042] The coating of the inventive food product can have any thickness known in the art, and generally has a thickness of at least 50 .m. Preferably, the thickness of the coating is at least 100 .m, more preferably at least 200 .m and most preferably at least 250 .m, and preferably at most 2 mm, more preferably at most 1.5 mm and most preferably at most 1.2 mm. The thickness of the coating can be determined using light microscopy and scanning electron microscopy.

[0043] In one embodiment, the food product comprises at least 5 wt% coating, based on the total dry weight of the food product. Preferably, the inventive food product comprises at least 10 wt% coating, more preferably at least 20 wt% coating, even more preferably at least 30 wt% coating and most preferably at least 40 wt% coating, and preferably at most 90 wt% coating, more preferably at most 80 wt% coating and most preferably at most 70 wt% coating, based on the total dry weight of the food product. This value is determined by separating the coating from the core e.g. by using a knife, and weighing the coating.

[0044] In one embodiment of the invention, the starch in the coating is at least 60 wt% gelatinized. With “gelatinization” or “gelatinized” reference is made to the phenomenon occurring when starch is exposed to water and heat in which starch granules primarily absorb water, swell and eventually burst out to form a gel. Preferably, the inventive coating comprises starch which is at least 70 wt% gelatinized, more preferably at least 80 wt% gelatinized and most preferably at least 90 wt% gelatinized, and preferably at most 100 wt% gelatinized, more preferably at most 99 wt% gelatinized and most preferably at most 95 wt% gelatinized. The degree of gelatinization can be determined using any suitable method known in the art. Examples of suitable methods include light microscopy and electron microscopy. The advantage of gelatinized starch is that amylopectin may form a glassy structure which contributes to the crispiness of the coating of the potato food product.

[0045] In one embodiment, the coating comprises at least 1 wt% fat, based on the total dry weight of the coating. Preferably, the coating comprises at least 2 wt% fat, more preferably at least 3 wt% fat, even more preferably at least 4 wt% fat and most preferably at least 5 wt% fat, and preferably at most 50 wt% fat, more preferably at most 45 wt% fat and most preferably at most 40 wt% fat, based on the total dry weight of the coating. The total dry weight is defined as the total weight of the coating without water. The amount of fat can be determined with methods known in the art including organic solvent extraction. An example of such a technique is the ISO 6492 method. This value is determined by separating the coating from the core e.g. by using a knife, and using the coating.

[0046] In one embodiment, the coating comprises a starch. The starch can be any starch known in the art and suitable for use in coatings for potato food products. Examples of suitable starches include rice starch, corn starch, wheat starch, pea starch and potato starch. The starch can be unmodified or modified. Also two or more starches are contemplated. In one embodiment, the starch is a non-modified or modified starch obtained from the mechanical peel.

[0047] In one embodiment, the coating comprises at least 20 wt% starch, more preferably at least 30 wt% starch, even more preferably at least 40 wt% starch and most preferably at least 50 wt% starch, and preferably at most 99 wt% starch, more preferably at most 95 wt% starch, even more preferably at most 90 wt% starch and most preferably at most 80 wt% starch, based on the total dry weight of the coating. The amount of starch can be determined using any suitable method known in the art. Examples of a suitable method include spectrophotometric methods such as the method of NEN-EN-ISO 15914. This value is determined by separating the coating from the core e.g. by using a knife, and using the coating.

[0048] In one embodiment, the coating comprises at least 0.1 wt% protein, based on the total dry weight of the coating. Preferably, the coating comprises at least 0.2 wt% protein, more preferably at least 0.5 wt% protein, even more preferably at least 1.0 wt% protein and most preferably at least 15 wt% protein, and preferably at most 40 wt% protein, more preferably at most 30 wt% protein, even more preferably at most 25 wt% protein and most preferably at most 20 wt% protein, based on the total dry weight of the coating. Various methods have been described in literature to determine the protein content. For the purposes of this application, the Kjeldahl method is used to determine the nitrogen content, which is then converted to protein content. The Kjeldahl is well established and well known to the person skilled in the art. In this application the Kjeldahl method is performed by hydrolyzing a sample using H2SO4 at 420°C for 2 hours, during which the proteins will be converted to ammonia. The generated ammonia is distilled off and the amount of nitrogen is measured by titration. The amount of protein is calculated by multiplying the nitrogen content by the conversion factor of 6.25 (nitrogen to protein factor).

[0049] In one embodiment, the coating comprises at most 10 wt% water, based on the total weight of the coating. Preferably, the coating comprises at most 9 wt% water, more preferably at most 8 wt% water, even more preferably at most 6 wt% water and most preferably at most 5 wt% water, and preferably at least 0.1 wt% water, more preferably at least 0.2 wt% water, even more preferably at least 0.5 wt% water and most preferably at least 1 wt% water, based on the total weight of the coating.

[0050] In one embodiment, the coating comprises an additive. The additive can be any additive known in the art. Such additives include other starch, pigments, (inorganic) fillers, fibers, proteins, flavouring agents, anti-oxidants, preservatives, herbs, salt, rheology modifiers such as xanthan, sugars and colouring agents.

[0051] In one embodiment of the invention, the coating comprises at least 1 wt% of the additive. Preferably, the inventive coating comprises at least 2 wt% additive, more preferably at least 5 wt% additive, even more preferably at least 10 wt% additive and most preferably at least 15 wt% additive, and preferably at most 60 wt% additive, more preferably at most 50 wt% additive and most preferably at most 40 wt% additive, based on the total dry weight of the coating. The amounts of starch, fat, water, additives and any other components add up to 100% by weight of the coating. The amounts of the core and the coating add up to 100% by weight of the potato food product.

[0052] In a further embodiment, the potato food product is frozen.

[0053] The invention further pertains to a process for preparing a potato food product comprising a core and a coating covering the core, wherein the core is obtained by mechanical peeling, comprising the steps of:

[0054] (a) mechanically peeling a potato to obtain a potato body and a potato peel;

[0055] (b) cutting the potato body to form the core of the potato food product;

[0056] (c) comminuting the potato peel to obtain a starch-containing side stream;

[0057] (d) separating starch from the starch-containing side stream to obtain a non-modified starch;

[0058] (e) modifying the obtained starch to obtain a modified starch;

[0059] (f) adding the modified starch and optionally the non-modified starch to a batter;

[0060] (g) optionally applying the batter to the core of the potato food product to obtain a potato food product; and

[0061] (h) optionally pre-frying the potato food product.

[0062] The process of the invention for preparing the inventive potato food products requires less energy and water compared to the use of the conventional steam peel process. The inventive process also enables the use of significantly more of the potato as raw material for food products and other products compared to steam peal processes. Also, steam peeling is generally performed at a higher temperature than mechanical peeling, which may increase undesirable microbial growth. Moreover, mechanical peeling does not require safety measures for dealing with processing steam. Additionally, mechanical peeling does not emit smell, (hissing) sound and steam to the environment as opposed to steam peeling.

[0063] In step (a) of the inventive process, potato is mechanically peeled to obtain a potato body and a potato peel. Mechanical peeling of potatoes can be performed using any method known in the art for peeling potatoes. Mechanical peeling can be performed using abrasive means such as stiff brushes, carborundum rollers or revolving bowls or drums with abrasive surfaces; and non-abrasive means such as stationary knives or razor-like blades. Preferably, mechanical peeling is performed using abrasive means, more preferably using carborundum rollers.

[0064] In one embodiment, the temperature in step (a) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C.

[0065] In step (b), the potato body is cut to form the core of the potato food product. Cutting of the potato body can be performed using any method known in the art. Examples of such potato cutters include straight cutters, wedge cutters, crinkle cutters and spiral cutters. The cutters can create strips in any desired form and in any desired thickness.

[0066] In one embodiment, the temperature in step (b) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (b) is the same as the temperature in step (a).

[0067] In step (c), the potato peel obtained in step (a) is comminuted to obtain a starch-containing side stream. Comminution refers to the process of reducing the size of the potato peel. Comminution of the potato peel can be performed using any method known in the art. Examples of such comminution methods include cutting, meshing and grinding. Two or more comminution steps are contemplated. Comminution can be carried out without adding water and by adding water. In one embodiment, other potato starch-containing side streams may be added before, during or after step (c) of the inventive process. Examples of such starch- containing side stream can be starch from potato cut side stream from cutting peeled potatoes, reject streams from mechanical and optical sorters and cut potatoes which are not according to specifications.

[0068] In one embodiment, the temperature in step (c) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (c) is the same as the temperature in step (a).

[0069] In step (d), starch is separated from the starch-containing side stream to obtain non-modified starch. Starch can be separated using any method known in the art. Examples of separation methods include filtering, cyclone separation, centrifuging and decanting. Preferably, the non-modified starch obtained in step (d) is a native starch.

[0070] In one embodiment, the temperature in step (d) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (d) is below the gelatinization temperature of the potato starch. Preferably, the temperature in step (d) is the same as the temperature in step (c).

[0071] Optionally, the non-modified starch is modified to obtain a modified starch. Such modification can be any modification known in the art. Such modifications include surface modification, introducing anionic, zwitterionic and / cationic groups and crosslinking. Preferably, the modified starch is a crosslinked starch. Crosslinking can be performed using phosphorcontaining crosslinking agents such as metaphosphate. Preferably, the crosslinked starches can be suitably used in batters for potato food products such as potato fries.

[0072] In step (f), the modified starch obtained in step (e) and optionally the non-modified starch obtained in step (d) are added to a batter. The batter may be any batter known in the art. In one embodiment, the batter comprises at least 20 wt% starch, more preferably at least 30 wt% starch, even more preferably at least 40 wt% starch and most preferably at least 50 wt% starch, and preferably at most 99 wt% starch, more preferably at most 95 wt% starch, even more preferably at most 90 wt% starch and most preferably at most 80 wt% starch, based on the total dry weight of the batter. The amount of starch can be determined using any suitable method known in the art. Examples of a suitable method include spectrophotometric methods such as the method of NEN-EN-ISO 15914.

[0073] In one embodiment, the batter comprises at least 20 wt% modified starch, more preferably at least 30 wt% modified starch, even more preferably at least 40 wt% modified starch and most preferably at least 50 wt% modified starch, and preferably at most 100 wt% modified starch, more preferably at most 99 wt% modified starch, even more preferably at most 95 wt% modified starch, even more preferably at most 90 wt% modified starch and most preferably at most 80 wt% modified starch, based on the total dry weight of the batter. The amount of modified starch can be determined using any suitable method known in the art. It is contemplated that the batter comprises the modified starch as the sole starch component.

[0074] In one embodiment, the batter comprises at least 20 wt% non-modified starch, more preferably at least 30 wt% non-modified starch, even more preferably at least 40 wt% nonmodified starch and most preferably at least 50 wt% non-modified starch, and preferably at most 99 wt% non-modified starch, more preferably at most 95 wt% non-modified starch, even more preferably at most 90 wt% non-modified starch, even more preferably at most 85 wt% non-modified starch and most preferably at most 80 wt% non-modified starch, based on the total dry weight of the batter. The amount of modified starch can be determined using any suitable method known in the art. The non-modified starch is generally used in combination with the modified starch. Using only non-modified starch or native starch in the batter generally leads to a coated food product, preferably a potato fry, which is sticky prior to the par-frying step and leads to agglomeration of potato fries, which is undesirable.

[0075] In one embodiment, the weight ratio of the modified starch and the non-modified starch is at least 0.01 , preferably the weight ratio is at least 0.1, more preferably at least 0.2 and most preferably at least 0.5, and preferably at most 100, more preferably at most 50, even more preferably at most 20 and most preferably at most 10.

[0076] In one embodiment, the batter comprises at least 10 wt% water, based on the total weight of the first coating composition. Preferably, the batter comprises at least 20 wt% water, more preferably at least 30 wt% water, even more preferably at least 35 wt% water and most preferably at least 40 wt% water, and preferably at most 80 wt% water, more preferably at most 70 wt% water, even more preferably at most 65 wt% water and most preferably at most 60 wt% water, based on the total weight of the batter.

[0077] In one embodiment, the batter may further comprise a food-grade additive. Examples of such food-grade additives includes protein, sugars, (dietary) fibers, cross-linking agents, preservatives, flavouring agents, rheology modifiers such as xanthan, and colouring agents.

[0078] In one embodiment of the invention, the batter comprises at least 1 wt% of the food-grade additive. Preferably, the batter comprises at least 2 wt% food-grade additive, more preferably at least 5 wt% food-grade additive, even more preferably at least 10 wt% foodgrade additive and most preferably at least 15 wt% food-grade additive, and preferably at most 50 wt% food-grade additive, more preferably at most 40 wt% food-grade additive and most preferably at most 30 wt% food-grade additive, based on the total weight of the batter.

[0079] The amounts of starch, food-grade additives and any other components add up to 100% by weight of the batter.

[0080] In optional step (g) of the inventive process, the batter is applied to the core of the potato food product to obtain the potato food product. The application of the batter can be performed using any method known in the art. Such application methods include submerging and spraying.

[0081] In one embodiment, the temperature in step (g) is maintained at a temperature above 5°C. Preferably, the temperature is at least 10°C, more preferably at least 15°C, more preferably at least 20°C and most preferably at least 25°C, and preferably at most 65°C, more preferably at most 60°C, and most preferably at most 50°C. Preferably, the temperature in step (g) is below the gelatinization temperature of the potato starch. Preferably, the temperature in step (g) is the same as the temperature in step (b). In optional step (h), the potato food product is pre-fried or par-fried. Pre-frying or par-frying refers to the heating of the potato food product at a temperature where the starch in the batter and / or the starch present in the core is gelatinized. During the pre-frying step also a coating is formed which generally is uniformly distributed across the core and is covering the core. Such a coating may provide crunchiness to the potato food product. This heating can be performed in (vegetable) oil, in an oven, in an air-fryer, in an impingement oven or in a vacuum fryer. Preferably, the heating is performed in oil.

[0082] In one embodiment, the temperature in step (h) is maintained at a temperature above 140°C. Preferably, the temperature is at least 150°C, more preferably at least 155°C, more preferably at least 160°C and most preferably at least 165°C, and preferably at most 190°C, more preferably at most 185°C, and most preferably at most 180°C.

[0083] In one embodiment, the residence time of the potato food product during pre-frying, preferably in the oil, is at least 20 seconds. Preferably, the residence time is at least 30 seconds, more preferably at least 45 seconds and most preferably at least 60 seconds, and preferably at most 5 minutes, more preferably at most 4 minutes and most preferably at most 3 minutes. A shorter residence time is desirable as it is technically and economically more attractive.

[0084] In a further embodiment of the inventive process, the potato food product is frozen. The freezing process can be performed using methods known in the art. In one embodiment, the temperature of the potato food product is maintained at a temperature of at most 0°C. Preferably, the temperature is at most -5°C, more preferably at most -10°C, more preferably at most -15°C and most preferably at most -18°C, and preferably at least -40°C, more preferably at least -30°C, and most preferably at least -25°C.

[0085] The invention further pertains to a product obtained with the above process for preparing a food product. In one embodiment, the product is a batter. Preferably, the product or the batter comprises a non-modified starch and / or modified starch obtained with the above process.

[0086] The invention is exemplified in the following Examples.

[0087] Examples

[0088] Example 1: mechanical peeling

[0089] 200 kg of Fontane potatoes were mechanically peeled using a carborundum peeler (peeling time of 90 seconds). 168 kg of peeled potatoes with hardly any defects and 32 kg of potato peel (16% of total potato) were obtained. For comparison, 200 kg of Fontane potatoes were peeled using a conventional steam peeler. 180 kg of peeled potatoes (10% of total potato) were obtained. The peeled potatoes had more defects than the mechanically peeled potatoes.

[0090] Example 2: native starch

[0091] 20 kg of potato peel of Example 1 were suspended in water and ground in a grinder (plate distance 200 .m) in order to free the native starch. The obtained suspension is subsequently separated in a decanter unit at 3,500g for 10 minutes. The solid is dried at 50°C for 16 hours. The dried solid was white and contained native potato starch. The yield of potato starch was about 95%.

[0092] Example 3: modified starch

[0093] 2580 g of native starch of Example 2 were suspended in 4920 mL water. 75 g of sodium chloride was added to the suspension, and subsequently 1 M sodium hydroxide solution was added dropwise until the pH was 11 . The suspension was heated to 45°C and mixed, after which 18 g STMP (trisodium trimetaphosphate) was added. The reaction suspension was mixed for 5 hours at 45°C. Subsequently, 25% hydrogen sulfate solution was added dropwise to reach a pH of 5.5. The mixture was filtered over a vacuum filter (glass fiber filter P3). The solids were washed with water and filtered again over the vacuum filter. This washing step was repeated twice. A suspension of the modified potato starch was obtained (with 55 wt% dry matter).

[0094] Example 4: batter with modified starch

[0095] 1757 g of modified starch suspension of Example 3 are mixed with 1.56 g xanthan gum. This mixture is added to 1242 g water and mixed in a Magimix kitchen machine for 2 minutes to obtain the batter of Example 4 (with 30.8 wt% dry matter).

[0096] Example 5: potato fries

[0097] The peeled potatoes of Example 1 were cut in strips (8.7 x 8.7 mm), blanched at 70°C for 3 minutes and dried. 500 g of dried potato fries were coated with the batter of Example 4. The batter uptake was 14.0 wt%, based on the weight of the dried potato strips. The battered potato fries were fried in sunflower oil at 175 °C for 60 seconds. The potato fries did not stick. The crispiness of the par-fried potato fries was significantly better than non-battered, par-fried potato fries.

[0098] For comparison, steam-peeled potato strips were battered and par-fried in a similar manner as described above. Both batches of par-fried potato fries were cooled and frozen. Both the mechanically peeled and the steam peeled frozen potato fries were analyzed using a scanning electron microscope (SEM). The battered potato fries according to the invention revealed the potato core and a single coating layer attributed to the applied batter. The steam peeled, battered potato fries (comparative) showed the potato core, an intermediate layer attributed to the cooking ring (obtained due to the steam peeling process), and a top layer attributed to the applied batter.

[0099] Example 6: potato cut water

[0100] Native starch was isolated according to the process described in Example 2, except that the potato starch was from potato cut water. The isolated native starch was modified according to the process of Example 3, and a batter was prepared according to the process of Example 4.

[0101] The peeled potatoes of Example 1 were cut in strips (8.7 x 8.7 mm), blanched at 70°C for 3 minutes and dried. 500 g of dried potato fries were coated with the batter of this Example. The batter uptake was 17.8 wt%, based on the weight of the dried potato strips. The battered potato fries were fried in sunflower oil at 175 °C for 60 seconds. The potato fries did not stick. The crispiness of the par-fried potato fries was significantly better than non-battered, par-fried potato fries and comparable to the par-fried potato fries of Example 5.

Claims

CLAIMS1. A process for preparing a batter comprising the steps of:(a) providing a starch-containing side stream of potato processing process;(b) optionally comminuting the starch-containing side stream;(c) separating starch from the starch-containing side stream to obtain a non-modified starch;(d) modifying the obtained starch to obtain a modified starch;(e) adding the modified starch and optionally the non-modified starch to a batter; and(f) optionally applying the batter to a food product, wherein the non-modified and modified starch are not gelatinized.

2. Process according to claim 1 wherein the starch-containing side stream is a potato peel obtained from mechanical peeling.

3. Process according to any one of claims 1 and 2 wherein the starch-containing side stream is an aqueous potato cut side stream and / or a reject stream from mechanical and optical sorters.

4. Process according to any one of claims 1 to 3 wherein the modified starch is a starch which is at least partially crosslinked.

5. A product obtained by any one of claim 1 to 4.

6. Product according to claim 5 wherein the product is a batter.

7. Product according to claim 5 wherein the product comprises a non-modified and / or a modified starch.

8. Potato food product comprising a core and a coating covering the core, wherein the core is obtained by mechanical peeling.

9. Potato food product according to claim 8, wherein the coating comprises starch and optionally fat.

10. Potato food product according to any one of claims 8 and 9, wherein the core comprises straight and / or corner cuts at the ends of the food product.

11. Potato food product according to any one of claims 8 to 11 , wherein the coating comprises starch which is at least partially gelatinized.

12. Potato food product according to any one of claims 8 to 12 comprising at least 1 wt% fat, based on the total weight of the food product.

13. Potato food product according to any one of claims 8 to 13 wherein the core comprises starch which is at least partially gelatinized.

14. Potato food product according to any one of claims 8 to 14 wherein the coating comprises modified or unmodified starch obtained from the mechanical potato peel.

15. A process for preparing a potato food product comprising a core and a coating covering the core, wherein the core is obtained by mechanical peeling, comprising the steps of:(a) mechanically peeling a potato to obtain a potato body and a potato peel;(b) cutting the potato body to form the core of the potato food product;(c) comminuting the potato peel to obtain a starch-containing side stream;(d) separating starch from the starch-containing side stream to obtain a non-modified starch;(e) modifying the obtained starch to obtain a modified starch;(f) adding the modified starch and optionally the non-modified starch to a batter;(g) applying the batter to the core of the potato food product to obtain a potato food product; and(h) optionally pre-frying the potato food product