WO2007097625A2 - Process and device for preparing pre-fried or deep-fried starch containing food products - Google Patents

Process and device for preparing pre-fried or deep-fried starch containing food products Download PDF

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Publication number
WO2007097625A2
WO2007097625A2 PCT/NL2007/050073 NL2007050073W WO2007097625A2 WO 2007097625 A2 WO2007097625 A2 WO 2007097625A2 NL 2007050073 W NL2007050073 W NL 2007050073W WO 2007097625 A2 WO2007097625 A2 WO 2007097625A2
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WO
WIPO (PCT)
Prior art keywords
food product
starch containing
containing food
fried
moisture content
Prior art date
Application number
PCT/NL2007/050073
Other languages
French (fr)
Other versions
WO2007097625A3 (en
Inventor
Christianus Petrus Verberne
Eugenius Paulus Henricus Maria Schijvens
Original Assignee
Agrotechnology And Food Innovations B.V.
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Application filed by Agrotechnology And Food Innovations B.V. filed Critical Agrotechnology And Food Innovations B.V.
Publication of WO2007097625A2 publication Critical patent/WO2007097625A2/en
Publication of WO2007097625A3 publication Critical patent/WO2007097625A3/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3554—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for determining moisture content
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
    • A23L19/10—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops
    • A23L19/12—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops of potatoes
    • A23L19/18—Roasted or fried products, e.g. snacks or chips
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
    • A23L19/10—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops
    • A23L19/12—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops of potatoes
    • A23L19/18—Roasted or fried products, e.g. snacks or chips
    • A23L19/19—Roasted or fried products, e.g. snacks or chips from powdered or mashed potato products
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
    • A23L5/10—General methods of cooking foods, e.g. by roasting or frying
    • A23L5/11—General methods of cooking foods, e.g. by roasting or frying using oil
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L7/00—Cereal-derived products; Malt products; Preparation or treatment thereof
    • A23L7/10—Cereal-derived products
    • A23L7/117—Flakes or other shapes of ready-to-eat type; Semi-finished or partly-finished products therefor
    • A23L7/13—Snacks or the like obtained by oil frying of a formed cereal dough
    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
    • A47J37/00—Baking; Roasting; Grilling; Frying
    • A47J37/12—Deep fat fryers, e.g. for frying fish or chips
    • A47J37/1266—Control devices, e.g. to control temperature, level or quality of the frying liquid
    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
    • A47J37/00—Baking; Roasting; Grilling; Frying
    • A47J37/12—Deep fat fryers, e.g. for frying fish or chips
    • A47J37/1228—Automatic machines for frying and dispensing metered amounts of food
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/359—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using near infrared light

Definitions

  • the present invention relates to a process and a device for preparing pre-fried or deep-fried starch containing products wherein product properties are monitored on-line. These product properties are used to control the process for preparing the pre-fried or deep-fried starch containing food product.
  • the moisture content of pre-fried starch containing food products is an important parameter for the manufacturing process of the pre- fried starch containing food product and usually is one of the specifications that the end-product has to comply with.
  • Processes and devices for preparing pre-fried starch containing food products are well known in the art, cf. for example US 5.700.508, US 5.885.639, US 6.152.023, US 6.746.704 and the prior art cited therein.
  • the moisture content can only be effectively controlled by determining the moisture content during or shortly afterwards the food product has been subjected to the pre-frying process step and using the moisture data to control the pre-frying process step which results in reduced fluctuations of the moisture content of the end-product.
  • NIT Near Infrared Transmission
  • NIR Near Infrared Reflection
  • the pre-fried end product is subjected to a on line reflection measurement.
  • this method suffers from the disadvantage that only the moisture content of the exterior of the end product is determined. Since the exterior, i.e. the crust, of the pre-fried food product has a far lower moisture content than the interior of the pre-fried food product, the data obtained are not very reliable.
  • US 6.339.727 discloses a process of and an apparatus for controlling the distribution of potato chips across the width of a fryer in a commercial potato chips manufacturing line, wherein a plurality of substantially uniform potato slices are fed to a fryer by means of a conveyor. After being fried, the fried potato chips are discharged from the fryer exit, where a plurality of sensors detect the moisture content of the fried potato chips as a function of the location across the width of the fryer thereby generating signals that are representative for the moisture content. These signals are compared with a predetermined set of signals to determine whether variations in moisture content is present among the fried potato chips as a function of the location across the width of the fryer.
  • the moisture content of the fried potato chips is determined by using a M55 moisture sensor head that is used in the NIR-mode. Consequently, according to US 6.339.727, the moisture content of all fried potato chips, i.e. the final product, is determined and variations thereof with the predetermined values is used to determine how the potato slices are distributed on the conveyor which transports the potato slices to the fryer. The variations are therefore not used to directly control the frying process itself or to control the amount of heat to which the potato slices are subjected.
  • GB A 2.078.938 discloses a process of and an apparatus for determining the moisture content in a food product such as biscuits, i.e. the final product of a baking process, wherein a the moisture content of the food product is determined by radiation transmission, e.g. at the outlet of a baking oven, wherein radiation is employed at which moisture absorbs said radiation, e.g. a wave length of about 1200 nm.
  • the moisture content data are not used to control the baking process.
  • the present invention provides a process and a device for continuously measuring product parameters such as moisture content and fat content during the preparation process by NIT, wherein the data obtained are used to control the preparation process.
  • the present invention relates to a process for preparing a pre-fried or deep-fried starch containing food product, wherein: (a) a pre-cut starch containing food product is subjected to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-fried or deep-fried stage, wherein the moisture content between the fresh state and the pre-fried or deep-fried stage is reduced by 5 to 99 %, relative to the moisture content of the fresh state of the pre-cut starch containing food product;
  • step (b) a sample from the pre-cut starch containing food product is transferred during step (a) to a near- infrared transmission measuring means to measure the moisture content of the sample;
  • the present invention further relates to a device for preparing a pre-fried or deep- fried starch containing food product, said device comprising:
  • a heating means for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre- fried or deep-fried state;
  • a bypass for transferring a sample of the pre-cut starch containing food product to a near-infrared transmission measuring means to measure the moisture content of the sample;
  • control means for controlling the heating process to which the pre-cut starch containing food product is subjected in dependence of the measured moisture content of the sample.
  • Fig. 1 shows schematically a device for preparing a pre-fried starch containing food product according to the present invention.
  • the term "deep fried stage” is intended to define a stage wherein the starch containing food product is converted into a ready-to-eat state. For example, slices of potato can be “deep fried” to crisps.
  • the term "reference moisture content” is the moisture content that fulfils a certain process or product specification that is set before the process according to the invention is conducted. For example, pre-fried French fries must have a moisture content of about 60 to about 70 wt.% which according to the invention is then to be considered as the "reference moisture content”.
  • a fresh starch containing food product is to be understood as a food product comprising at least 10 wt.% of starch, based on the total weight of the food product. Preferable, the starch content is at least 12 wt.%.
  • the process according to the present invention is useful for several starch containing food products.
  • potatoes that are used for the production of French fries have preferably a moisture content that ranges from about 70 to about 85 wt.%, preferably from about 73 to about 82 wt.%, more preferably from about 76 to about 80 wt.%.
  • the end product has usually a moisture content that ranges from about 60 to about 70 wt.%. Consequently, the moisture content during the heating process must then be reduced by about 0 wt.% to about 30 wt.%, preferably by about 4 to about 27 wt.%, more preferably by about 8 to about 24 wt.%.
  • the end product has a moisture content that ranges from about 1 to about 3 wt.%. In that event, the moisture content during the heating process must then be reduced by about 96 to about 99 wt.%. According to the invention, it is therefore preferred that the moisture content between the fresh state and the pre-fried or deep-fried stage is reduced by about 0 to about 99 wt.%, relative to the moisture content of the pre-cut starch containing food product. Preferably the moisture content is reduced by about 1 to about 99 wt.%, more preferably about 5 to about 99 wt.%.
  • the moisture content is preferably reduced by about 0 to about 30 wt.%, more preferably about 4 to about 27 wt.%, even more preferably by about 8 to about 24 wt.%.
  • the moisture content is preferably reduced by about 96 to about 99 wt.%. Al the ranges for the reduction of moisture content are relative to the moisture content of the pre-cut starch containing food product.
  • the fat content of the food product will increase and this property can also be used to control the heating process.
  • high fat contents are usually not desired because of health risks and the like.
  • the fat content of pre-fried starch containing food products is within the range of 1 to 6 wt.%, based on the total weight of the food product.
  • the fat content of the deep-fried starch containing food products is preferably within the range of about 1 to about 40 wt.%.
  • the pre-fried or deep-fried starch containing food product is subjected to a cooling step (e).
  • a cooling step the moisture content is further reduced.
  • the quantity of the reduction is largely dependent from the cooling conditions, the size and shape of the food product and the like. It will however be understood by the person skilled in the art that the principles of monitoring the moisture content during the heating step can also be applied during the cooling step. Accordingly, during the cooling step a sample of the pre-fried or deep- fried starch containing food product is optionally transferred to a near-infrared transmission measuring means to measure the content of the sample, wherein the measured moisture content is compared with a reference moisture content.
  • the difference between the moisture content of the sample as obtained during or after the cooling step and that of the reference moisture content can then be used to control the cooling step.
  • the moisture content, measured during or after the heating step is optionally compared with a reference moisture content.
  • the difference between the moisture content of the sample as obtained during or after the heating step and that of the reference moisture content can then be used to control the cooling step.
  • the pre-cut starch containing food product is selected from the group consisting of potato, cassava, maize, cereals such as wheat and corn, and rice. More preferably, the pre-cut starch containing food product is potato.
  • the size of the pre-cut starch containing food product may vary widely and is dependent from the end product. For example, if French fries are to be prepared, the pre-cut starch containing food product will have a bar-like appearance. But if crisps are to be prepared, the pre-cut starch containing food product will have a thin slice-like appearance.
  • the pre-cut starch containing food product may be processed into a shaped fresh starch containing product and then subjected to the heating step.
  • the pre-cut starch containing food product may be processed, formed and extruded into the shaped fresh starch containing food product, optionally dried and then subjected to the heating step.
  • the pre-cut starch containing food product is processed into an extruded starch containing food product prior to step (a).
  • the pre-cut starch containing food product may be subjected to a blanching step prior to step (a).
  • the blanching step if preferably performed in hot water at a temperature of about 50° to about 95°C, preferably about 60° to about 90 0 C, during about 1 to about 30 minutes.
  • the blanching step is conducted at relatively low temperature, i.e. about 50° to about 70°°, this step is preferably performed for about 10 to about 30 minutes.
  • relatively high temperature i.e. about 70° to about 90 0 C
  • this step is preferably performed for about 1 to about 10 minutes.
  • the blanching step is preferably conducted if the pre-cut starch containing food product is potato. If the intended end product is a deep-fried food product, the heating step (a) is preferably conducted in edible or vegetable oil at a temperature of about 160° to about 190 0 C. If the intended end product is a pre-fried food product, the heating step (a) is preferably performed in edible or vegetable oil at a temperature of about 160° to about 190 0 C. After step (a), it is preferred that the pre-fried or deep-fried product is cooled as disclosed above, optionally frozen and packaged.
  • Fig. 1 shows schematically a device for preparing a pre-fried starch containing food product according to the present invention.
  • the device 1 comprises a conveying means 2 for conveying the food product through the device.
  • the conveying means 2 could be in any suitable form to transport the food product through the device, such as an endless conveyor belt or shaker conveyer.
  • conveying means 2 could also be a stream of liquid, such as a flow of frying fat in a deep frying arrangement.
  • Suitable devices are known in the art and for example disclosed in US 6.152.023.
  • the device further comprises a filling station 4 wherein a pre-cut starch containing food product is transferred to the conveying means.
  • filling station 4 is meant any apparatus suitable to supply a pre-cut starch containing food product to the conveying means and could comprise any preprocessing of the food product prior to the heating step. Therefore some examples of a filling station 4 are a hopper, a blanching device and a apparatus for performing a dipping step.
  • the conveying means 2 transports the food product to a heating unit 6.
  • the heating unit 6 is arranged for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-fried state.
  • the heating unit 6 can comprise a pre-drying unit 8 for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-dried state, and a deep-frying unit 10 for subjecting the pre- cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a pre-dried state into a pre-fried or deep-fried state.
  • the heating unit 6 could comprise only a pre-drying unit 8 or a deep-frying unit 10 dependent on the food product to be processed.
  • a heating unit 6 is a commonly known device and therefore not discussed in more detail.
  • samples of the pre-cut starch containing food product are taken from the conveying means 2 by means of a bypass 12.
  • the samples could be taken from the conveying means 2 by means of flaps in the conveying means 2, by blowing samples out of the stream of food product or by a chameleon principle.
  • options to take a sample out of the product stream are drawing system in the belt that periodically opens with the consequence that a little proportion of the production drops in a bypass belt that feeds the measuring unit 14, a blowing system that blows a sample out of the stream or a picking system that grabs the product from the production stream.
  • the bypass 12 transfers each sample of the pre-cut starch containing food product to a near-infrared transmission measuring unit 14.
  • the bypass 12 could be in the form of a shaker conveyer or any other conveyer device which prepares the samples to be measured.
  • the near-infrared transmission measuring unit 14 measures the moisture content of the sample. The measured moisture content is supplied to a control unit 16.
  • the measurement could be performed on a non-cooled product, which enables to make a simple bypass 12, as no cooling means are necessary in the bypass, and which enables to measure the moisture content very quickly after leaving the heating unit 6.
  • a fast determination of the moisture content enables to improve the controlling of the heating process in the heating unit 6 and consequently the quality of the food product.
  • the control unit 16 is arranged for controlling the heating process to which the pre-cut starch containing food product is subjected in dependence of the measured moisture content of the sample. For example, if the measured moisture content is higher than a reference moisture content, more moisture has to be evaporated. This could be done by lowering the speed of the conveying means in the heating unit 6, increasing the operating temperature in the heating unit 6 or decreasing the air humidity in the heating unit 6 or adapting a combination of said parameters.
  • the device could comprise a cooling unit 18 to convert the pre-cut starch containing food product from a pre-fried state into a pre-package state. The moisture content of the food product decreases during the cooling process in the cooling unit 18. Normally, the moisture content of the final food product is specified and defines the quality of the product.
  • parameters of the cooling process could be taken into account to control the process such that the moisture content of the final food product is within a specified range.
  • Process parameters which have a relationship with the cooling process in the cooling unit 18 are the air temperature in the cooling unit 18, the air humidity, the speed of the airflow over the food product, the thickness of the food product or the speed of the conveyer belt. With these parameters a prediction could be made of the release of moisture due to the cooling process. The release of moisture could be used to adapt the value of the reference moisture content in the control unit. The parameters could be measured with a thermometer, hydrometer and airflow meter. The thickness of the food product could be inputted by an operator or measured with suitable devices.
  • the respective measured parameters are supplied to the control unit 16 to determine new values of control parameters of the heating unit 6, such a the speed of the conveying means in the heating unit 6, the operating temperature in the heating unit 6, the air humidity in the heating unit 6.
  • the operating temperature could be the air temperature or deep fry fat temperature.
  • the controller unit 16 could be arranged to control the cooling process in the cooling unit 18, by adapting the speed of the conveyer belt, humidity, air temperature, air flow or any other suitable parameter which influences the release of moisture during the cooling process.
  • the control unit 16 could be in the form of dedicated hardware or a general purpose computer. In the latter case, a computer program is executed on the computer which determines in response to the measured moisture content or any other process parameters, new control parameters for the heating process in the heating unit 6 and/or cooling process in the cooling unit 18.
  • the conveying means 2 according to the invention is meant the whole system of conveying devices to transport the food product through the apparatus. Therefore, the heating unit 6, bypass and cooling unit 18 could comprise different and separate conveying means.

Abstract

The present invention relates to a process and a device for preparing pre-fried or deep-fried starch containing products wherein product properties are monitored on-line. These product properties are used to control the process for preparing the pre-fried or deep-fried starch containing food product. The product property that is monitored is in particular moisture content, using near infrared transmission.

Description

Process and device for preparing pre-fried or deep-fried starch containing food products
Field of the invention
The present invention relates to a process and a device for preparing pre-fried or deep-fried starch containing products wherein product properties are monitored on-line. These product properties are used to control the process for preparing the pre-fried or deep-fried starch containing food product.
Background of the invention
The moisture content of pre-fried starch containing food products such as pre- fried French fries is an important parameter for the manufacturing process of the pre- fried starch containing food product and usually is one of the specifications that the end-product has to comply with. Processes and devices for preparing pre-fried starch containing food products are well known in the art, cf. for example US 5.700.508, US 5.885.639, US 6.152.023, US 6.746.704 and the prior art cited therein. The moisture content can only be effectively controlled by determining the moisture content during or shortly afterwards the food product has been subjected to the pre-frying process step and using the moisture data to control the pre-frying process step which results in reduced fluctuations of the moisture content of the end-product. Obviously, such measurements must proceed relatively fast since the duration of the pre-frying process step is rather short. In the prior art, moisture contents of food products were determined by employing near infrared spectroscopy, wherein two different methods can be distinguished, i.e. Near Infrared Transmission (NIT) or Near Infrared Reflection (NIR). In the NIT method, pre-fried food product is homogenised and subjected to an on line transmission measurement. However, this method suffers from the disadvantage that it is relatively slow. Moreover, homogenising pre-fried starch containing food products such as pre-fried French fries is difficult thereby leading to unreliable results. In addition, the number of samples that can be measured within the time span of the pre- fry process step is rather limited.
In the NIR method, the pre-fried end product is subjected to a on line reflection measurement. However, this method suffers from the disadvantage that only the moisture content of the exterior of the end product is determined. Since the exterior, i.e. the crust, of the pre-fried food product has a far lower moisture content than the interior of the pre-fried food product, the data obtained are not very reliable.
US 6.339.727 discloses a process of and an apparatus for controlling the distribution of potato chips across the width of a fryer in a commercial potato chips manufacturing line, wherein a plurality of substantially uniform potato slices are fed to a fryer by means of a conveyor. After being fried, the fried potato chips are discharged from the fryer exit, where a plurality of sensors detect the moisture content of the fried potato chips as a function of the location across the width of the fryer thereby generating signals that are representative for the moisture content. These signals are compared with a predetermined set of signals to determine whether variations in moisture content is present among the fried potato chips as a function of the location across the width of the fryer. If such variations are present, they are used to alter the distribution of the potato slices on the conveyor in such a manner that the differences between the measured moisture content and the moisture content according to the predetermined set of signals is reduced. The moisture content of the fried potato chips is determined by using a M55 moisture sensor head that is used in the NIR-mode. Consequently, according to US 6.339.727, the moisture content of all fried potato chips, i.e. the final product, is determined and variations thereof with the predetermined values is used to determine how the potato slices are distributed on the conveyor which transports the potato slices to the fryer. The variations are therefore not used to directly control the frying process itself or to control the amount of heat to which the potato slices are subjected.
GB A 2.078.938 discloses a process of and an apparatus for determining the moisture content in a food product such as biscuits, i.e. the final product of a baking process, wherein a the moisture content of the food product is determined by radiation transmission, e.g. at the outlet of a baking oven, wherein radiation is employed at which moisture absorbs said radiation, e.g. a wave length of about 1200 nm. The moisture content data, however, are not used to control the baking process. The present invention provides a process and a device for continuously measuring product parameters such as moisture content and fat content during the preparation process by NIT, wherein the data obtained are used to control the preparation process.
Summary of the invention
The present invention relates to a process for preparing a pre-fried or deep-fried starch containing food product, wherein: (a) a pre-cut starch containing food product is subjected to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-fried or deep-fried stage, wherein the moisture content between the fresh state and the pre-fried or deep-fried stage is reduced by 5 to 99 %, relative to the moisture content of the fresh state of the pre-cut starch containing food product;
(b) a sample from the pre-cut starch containing food product is transferred during step (a) to a near- infrared transmission measuring means to measure the moisture content of the sample;
(c) the moisture content of the sample is compared to a reference moisture content; and
(d) the difference between the moisture content of the sample and the reference moisture content being used to adjust the amount of heat to which the pre-cut starch containing food product is subjected.
The present invention further relates to a device for preparing a pre-fried or deep- fried starch containing food product, said device comprising:
(a) a conveying means;
(b) a filling station wherein a pre-cut starch containing food product is transferred to the conveying means;
(c) a heating means for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre- fried or deep-fried state; (d) a bypass for transferring a sample of the pre-cut starch containing food product to a near-infrared transmission measuring means to measure the moisture content of the sample; and
(e) control means for controlling the heating process to which the pre-cut starch containing food product is subjected in dependence of the measured moisture content of the sample.
Short description of drawings
The present invention will be discussed in more detail below, using exemplary embodiments, with reference to the attached drawing, in which
Fig. 1 shows schematically a device for preparing a pre-fried starch containing food product according to the present invention.
Detailed description of the invention
The term "deep fried stage" is intended to define a stage wherein the starch containing food product is converted into a ready-to-eat state. For example, slices of potato can be "deep fried" to crisps. The term "reference moisture content" is the moisture content that fulfils a certain process or product specification that is set before the process according to the invention is conducted. For example, pre-fried French fries must have a moisture content of about 60 to about 70 wt.% which according to the invention is then to be considered as the "reference moisture content". According to the present invention, a fresh starch containing food product is to be understood as a food product comprising at least 10 wt.% of starch, based on the total weight of the food product. Preferable, the starch content is at least 12 wt.%.
The process according to the present invention is useful for several starch containing food products. For example, potatoes that are used for the production of French fries have preferably a moisture content that ranges from about 70 to about 85 wt.%, preferably from about 73 to about 82 wt.%, more preferably from about 76 to about 80 wt.%. In the production of pre-fried French fries, the end product has usually a moisture content that ranges from about 60 to about 70 wt.%. Consequently, the moisture content during the heating process must then be reduced by about 0 wt.% to about 30 wt.%, preferably by about 4 to about 27 wt.%, more preferably by about 8 to about 24 wt.%. However, if the potatoes are used for the production of ready-to-eat starch containing food products, e.g. crisps, the end product has a moisture content that ranges from about 1 to about 3 wt.%. In that event, the moisture content during the heating process must then be reduced by about 96 to about 99 wt.%. According to the invention, it is therefore preferred that the moisture content between the fresh state and the pre-fried or deep-fried stage is reduced by about 0 to about 99 wt.%, relative to the moisture content of the pre-cut starch containing food product. Preferably the moisture content is reduced by about 1 to about 99 wt.%, more preferably about 5 to about 99 wt.%.
If the fresh starch containing food product is to be prepared into a pre-fried starch containing food product, the moisture content is preferably reduced by about 0 to about 30 wt.%, more preferably about 4 to about 27 wt.%, even more preferably by about 8 to about 24 wt.%.
If the fresh starch containing food product is to be prepared into a ready to eat starch containing snack product like crisps, the moisture content is preferably reduced by about 96 to about 99 wt.%. Al the ranges for the reduction of moisture content are relative to the moisture content of the pre-cut starch containing food product.
During the heating process, the fat content of the food product will increase and this property can also be used to control the heating process. However, high fat contents are usually not desired because of health risks and the like. Usually and preferably, the fat content of pre-fried starch containing food products is within the range of 1 to 6 wt.%, based on the total weight of the food product.
The fat content of the deep-fried starch containing food products is preferably within the range of about 1 to about 40 wt.%.
After the heating step, it is preferred that the pre-fried or deep-fried starch containing food product is subjected to a cooling step (e). During this cooling step the moisture content is further reduced. However, the quantity of the reduction is largely dependent from the cooling conditions, the size and shape of the food product and the like. It will however be understood by the person skilled in the art that the principles of monitoring the moisture content during the heating step can also be applied during the cooling step. Accordingly, during the cooling step a sample of the pre-fried or deep- fried starch containing food product is optionally transferred to a near-infrared transmission measuring means to measure the content of the sample, wherein the measured moisture content is compared with a reference moisture content. The difference between the moisture content of the sample as obtained during or after the cooling step and that of the reference moisture content can then be used to control the cooling step. Alternatively, the moisture content, measured during or after the heating step, is optionally compared with a reference moisture content. The difference between the moisture content of the sample as obtained during or after the heating step and that of the reference moisture content can then be used to control the cooling step.
According to the invention, it is preferred that the pre-cut starch containing food product is selected from the group consisting of potato, cassava, maize, cereals such as wheat and corn, and rice. More preferably, the pre-cut starch containing food product is potato. The size of the pre-cut starch containing food product may vary widely and is dependent from the end product. For example, if French fries are to be prepared, the pre-cut starch containing food product will have a bar-like appearance. But if crisps are to be prepared, the pre-cut starch containing food product will have a thin slice-like appearance. Optionally, the pre-cut starch containing food product may be processed into a shaped fresh starch containing product and then subjected to the heating step. In particular when odd-shaped food products are desired, e.g. biscuits, cookies, pretzels, crackers, snacks, "wokkels" or "rosti", the pre-cut starch containing food product may be processed, formed and extruded into the shaped fresh starch containing food product, optionally dried and then subjected to the heating step. Hence, according to a preferred embodiment of the present invention, the pre-cut starch containing food product is processed into an extruded starch containing food product prior to step (a).
According to another preferred embodiment of the present invention, the pre-cut starch containing food product may be subjected to a blanching step prior to step (a). The blanching step if preferably performed in hot water at a temperature of about 50° to about 95°C, preferably about 60° to about 900C, during about 1 to about 30 minutes. In particular, if the blanching step is conducted at relatively low temperature, i.e. about 50° to about 70°°, this step is preferably performed for about 10 to about 30 minutes. On the other hand, if the blanching step is conducted at relatively high temperature, i.e. about 70° to about 900C, this step is preferably performed for about 1 to about 10 minutes. The blanching step is preferably conducted if the pre-cut starch containing food product is potato. If the intended end product is a deep-fried food product, the heating step (a) is preferably conducted in edible or vegetable oil at a temperature of about 160° to about 1900C. If the intended end product is a pre-fried food product, the heating step (a) is preferably performed in edible or vegetable oil at a temperature of about 160° to about 1900C. After step (a), it is preferred that the pre-fried or deep-fried product is cooled as disclosed above, optionally frozen and packaged.
Fig. 1 shows schematically a device for preparing a pre-fried starch containing food product according to the present invention. The device 1 comprises a conveying means 2 for conveying the food product through the device. The conveying means 2 could be in any suitable form to transport the food product through the device, such as an endless conveyor belt or shaker conveyer. However, conveying means 2 could also be a stream of liquid, such as a flow of frying fat in a deep frying arrangement. Suitable devices are known in the art and for example disclosed in US 6.152.023.
The device further comprises a filling station 4 wherein a pre-cut starch containing food product is transferred to the conveying means. It should be noted that with filling station 4 is meant any apparatus suitable to supply a pre-cut starch containing food product to the conveying means and could comprise any preprocessing of the food product prior to the heating step. Therefore some examples of a filling station 4 are a hopper, a blanching device and a apparatus for performing a dipping step. The conveying means 2 transports the food product to a heating unit 6. The heating unit 6 is arranged for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-fried state. The heating unit 6 can comprise a pre-drying unit 8 for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-dried state, and a deep-frying unit 10 for subjecting the pre- cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a pre-dried state into a pre-fried or deep-fried state. It should be noted the heating unit 6 could comprise only a pre-drying unit 8 or a deep-frying unit 10 dependent on the food product to be processed. A heating unit 6 is a commonly known device and therefore not discussed in more detail.
After the food product has been subjected to the heating process in the heating unit 6, samples of the pre-cut starch containing food product are taken from the conveying means 2 by means of a bypass 12. The samples could be taken from the conveying means 2 by means of flaps in the conveying means 2, by blowing samples out of the stream of food product or by a chameleon principle. In other words options to take a sample out of the product stream are drawing system in the belt that periodically opens with the consequence that a little proportion of the production drops in a bypass belt that feeds the measuring unit 14, a blowing system that blows a sample out of the stream or a picking system that grabs the product from the production stream. The bypass 12 transfers each sample of the pre-cut starch containing food product to a near-infrared transmission measuring unit 14. The bypass 12 could be in the form of a shaker conveyer or any other conveyer device which prepares the samples to be measured. The near-infrared transmission measuring unit 14 measures the moisture content of the sample. The measured moisture content is supplied to a control unit 16.
The measurement could be performed on a non-cooled product, which enables to make a simple bypass 12, as no cooling means are necessary in the bypass, and which enables to measure the moisture content very quickly after leaving the heating unit 6.
A fast determination of the moisture content enables to improve the controlling of the heating process in the heating unit 6 and consequently the quality of the food product.
The control unit 16 is arranged for controlling the heating process to which the pre-cut starch containing food product is subjected in dependence of the measured moisture content of the sample. For example, if the measured moisture content is higher than a reference moisture content, more moisture has to be evaporated. This could be done by lowering the speed of the conveying means in the heating unit 6, increasing the operating temperature in the heating unit 6 or decreasing the air humidity in the heating unit 6 or adapting a combination of said parameters. Optionally, the device could comprise a cooling unit 18 to convert the pre-cut starch containing food product from a pre-fried state into a pre-package state. The moisture content of the food product decreases during the cooling process in the cooling unit 18. Normally, the moisture content of the final food product is specified and defines the quality of the product. To enhance the process, parameters of the cooling process could be taken into account to control the process such that the moisture content of the final food product is within a specified range. Process parameters which have a relationship with the cooling process in the cooling unit 18 are the air temperature in the cooling unit 18, the air humidity, the speed of the airflow over the food product, the thickness of the food product or the speed of the conveyer belt. With these parameters a prediction could be made of the release of moisture due to the cooling process. The release of moisture could be used to adapt the value of the reference moisture content in the control unit. The parameters could be measured with a thermometer, hydrometer and airflow meter. The thickness of the food product could be inputted by an operator or measured with suitable devices. The respective measured parameters are supplied to the control unit 16 to determine new values of control parameters of the heating unit 6, such a the speed of the conveying means in the heating unit 6, the operating temperature in the heating unit 6, the air humidity in the heating unit 6. The operating temperature could be the air temperature or deep fry fat temperature.
Optionally the controller unit 16 could be arranged to control the cooling process in the cooling unit 18, by adapting the speed of the conveyer belt, humidity, air temperature, air flow or any other suitable parameter which influences the release of moisture during the cooling process. The control unit 16 could be in the form of dedicated hardware or a general purpose computer. In the latter case, a computer program is executed on the computer which determines in response to the measured moisture content or any other process parameters, new control parameters for the heating process in the heating unit 6 and/or cooling process in the cooling unit 18. It should be noted with the conveying means 2 according to the invention is meant the whole system of conveying devices to transport the food product through the apparatus. Therefore, the heating unit 6, bypass and cooling unit 18 could comprise different and separate conveying means. Several embodiment of the present invention have been described above by way of exemplary embodiments. Various modifications and variations for the elements described with respect to these embodiments may be made by the skilled person without departing from the scope of the present invention, which is defined by the appended claims.

Claims

Claims
1. A process for preparing a pre-fried or deep-fried starch containing food product, wherein: (a) a pre-cut starch containing food product is subjected to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-fried or deep-fried stage, wherein the moisture content between the fresh state and the pre-fried or deep-fried stage is reduced by 5 to 99 %, relative to the moisture content of the fresh state of the pre-cut starch containing food product;
(b) a sample from the pre-cut starch containing food product is transferred during step (a) to a near-infrared transmission measuring means to measure the moisture content of the sample;
(c) the moisture content of the sample is compared to a reference moisture content; and
(d) the difference between the moisture content of the sample and the reference moisture content being used to adjust the amount of heat to which the pre- cut starch containing food product is subjected.
2. The process according to claim 1, wherein the moisture content of the pre-cut starch containing food product is 70 to 85 wt%, based on the total weight of the pre-cut starch containing food product.
3. The process according to claim 1 or claim 2, wherein the fat content of the pre- fried or deep fried starch containing food product is 1 to 40 wt.%, based on the total weight of the pre-cut starch containing food product.
4. The process according to any one of the preceding claims, wherein the process further comprises (e) cooling the food product, and (f) determining the moisture of the cooled food product content according to steps (b) - (d).
5. The process according to any one of the preceding claims, wherein the pre-cut starch containing food product is selected from the group consisting of potato, cassava, maize, wheat and rice.
6. The process according to any one of the preceding claims, wherein the pre-cut starch containing food product is subjected to a blanching step prior to step (a).
7. The process according to any one of the preceding claims, wherein the pre-cut starch containing food product is processed into an extruded starch containing food product prior to step (a).
8. A device for preparing a pre-fried starch containing food product, said device comprising:
(a) a conveying means;
(b) a filling station wherein a pre-cut starch containing food product is transferred to the conveying means;
(c) a heating means for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-fried or deep-fried state;
(d) a bypass for transferring a sample of the pre-cut starch containing food product to a near-infrared transmission measuring means to measure the moisture content of the sample; and
(e) control means for controlling the heating process to which the pre-cut starch containing food product is subjected in dependence of the measured moisture content of the sample.
9. Device according to claim 8, wherein the heating means comprises: (cl) pre-drying means for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a fresh state into a pre-dried state; (c2) deep-frying means for subjecting the pre-cut starch containing food product, carried by the conveying means, to an amount of heat during a sufficient period of time to convert the pre-cut starch containing food product from a pre- dried state into a pre-fried or deep-fried state.
10. Device according to claim 8 or claim 9, wherein the control means further is adapted to control at least one out of: - speed of the conveying means in the heating means;
- operating temperature in the heating means;
- air humidity in the heating means.
11. Device according to any one of claims 8 - 10, wherein the device further comprises:
(f) a cooling means to convert the pre-cut starch containing food product from a pre-fried or deep-fried state into a pre-package state.
12. Device according to any one of claims 8 - 11, wherein the device further comprises measuring means to measure a parameter having a relationship with the converting process in the cooling means, and wherein the control means further are adapted to control the heating process in dependence of said parameter.
PCT/NL2007/050073 2006-02-21 2007-02-21 Process and device for preparing pre-fried or deep-fried starch containing food products WO2007097625A2 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107593834A (en) * 2016-07-12 2018-01-19 日清食品控股株式会社 The forming method of frying product mixture
CN111257271A (en) * 2020-03-02 2020-06-09 滕州市界河镇农业综合服务中心 Potato autofilter device based on spectrum technique
EP3541765B1 (en) 2016-11-18 2021-08-18 Knauf Gips KG Process and apparatus for calcination of gypsum

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2078938A (en) * 1980-06-27 1982-01-13 United Biscuits Ltd Measurement of moisture content
US6339727B1 (en) * 1998-12-21 2002-01-15 Recot, Inc. Apparatus and method for controlling distribution of product in manufacturing process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2078938A (en) * 1980-06-27 1982-01-13 United Biscuits Ltd Measurement of moisture content
US6339727B1 (en) * 1998-12-21 2002-01-15 Recot, Inc. Apparatus and method for controlling distribution of product in manufacturing process

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107593834A (en) * 2016-07-12 2018-01-19 日清食品控股株式会社 The forming method of frying product mixture
EP3541765B1 (en) 2016-11-18 2021-08-18 Knauf Gips KG Process and apparatus for calcination of gypsum
CN111257271A (en) * 2020-03-02 2020-06-09 滕州市界河镇农业综合服务中心 Potato autofilter device based on spectrum technique
CN111257271B (en) * 2020-03-02 2020-10-09 滕州市界河镇农业综合服务中心 Potato autofilter device based on spectrum technique

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