Patent Application
20180368451
Fried crisps, equipment and method for making same is described herein. More specifically, this descriptions relates to a pulsed electric field and method for preparing fried crisps from fruits or vegetables.
Some fruits and vegetables are often difficult to subject to frying processes in the production of shelf stable snack foods. For example, produce comprises high amounts of reducing sugars, sucrose, starch, and/or solids may be difficult to fry to a shelf stable moisture content without significant burning.
Sweet potatoes are rich in fiber, protein, vitamins, minerals, starch, and antioxidants. However, due to their high reducing sugar content and acrylamide (>1000 ppb) levels following dehydration, their use in snack foods has been limited to vacuum frying technology, which is not always economically feasible. Conventional frying process are generally limited to use of only fresh produce and result in highly variable acrylamide contents, ranging from 500-2,000 ppb, for example, and diminished orange coloring. Thus, they are difficult to fry atmospherically to a shelf stable moisture content as they turn dark at around 2.5% moisture content. There is a need for an alternate solution to process these such produce without the high costs of vacuum frying and without the variability and inconsistent product resulting from conventional frying. In particular, given the popularity of kettle cooked potato chips, there is a need for a solution that produces the kettle cooked products' crisp sensation with a consistently appealing look and taste.
Provided herein are ready-to-eat fried crisps manufactured directly from raw sliced fruits or vegetables (i.e., produce). The crisps are shelf-stable and light in color despite the reducing sugar content present in the raw produce.
Below is a simplified summary of this disclosure meant to provide a basic understanding of some aspects of the products and methods described herein. This is not an exhaustive overview and is not intended to identify key or critical elements or to delineate the scope of the description. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description below.
In one aspect, disclosed herein is a method for making produce crisps comprises the steps of applying a pulse electric field to a plurality of raw whole produce in a pulsed electric field treatment chamber, the treatment chamber comprising a treatment space between a negative and a positive electrode, the negative and positive electrodes oriented in a vertical configuration; slicing the pulsed produce into slices; immediately blanching the slices in a water solution at a temperature of above 145° F. to form blanched produce slices; and frying the blanched produce slices to form a plurality of produce crisps with a shelf stable moisture content and an oil content of between about 28% to less than 44%.
In another aspect, a pulsed electric field treatment chamber comprises: an inner chamber comprising a predetermined water solution level; an upper conveyor belt having at least its bottom surface below the predetermined water solution level; a lower conveyor belt entirely below the predetermined water solution level; and a negative electrode opposite a positive electrode on either side of the lower conveyor belt, the negative electrode and the positive electrode oriented vertically and the negative electrode fully submerged within the predetermined water solution level, wherein said chamber is configured to provide a pulsed electric field to a treatment space between the bottom surface of the upper conveyer belt and a top surface of the lower conveyor belt, and between the negative electrode and the positive electrode.
Other aspects, embodiments and features of the invention will become apparent in the following written detailed description and accompanying drawings.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition is expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. When used in the appended claims, in original and amended form, the term “comprising” is intended to be inclusive or open-ended and does not exclude any additional, unrecited element, method, step or material. The term “consisting of” excludes any element, step or material other than those specified in the claim. As used herein, “up to” includes zero, meaning no amount (i.e., 0%) is added in some embodiments. The term “immediately” means as soon as practicable, without any intervening step(s).
As used herein, produce refers to fruits and/or vegetables grown by farming. In one embodiment, produce refers to root vegetables comprising solids in an amount between about 10% to about 40%. In one embodiment, produce refers to root vegetables comprising solids in an amount greater than about 30% by weight of the produce. In one embodiment, produce refers to root vegetables comprising solids in an amount between about 30% to about 40% by weight of the produce. In one embodiment, produce refers to root vegetables comprising solids in an amount between about 10% to about 25% by weight of the produce. In one embodiment, produce refers to root vegetables comprising solids in an amount between about 10% to about 20% by weight of the produce. In one embodiment, the raw produce for use with the method and product described herein comprises a high reducing sugar concentration of greater than about 0.05% to about 4.0%. In one embodiment, the sucrose content is greater than about 1% and up to about 6%. In one embodiment, the produce may comprise one or more of sweet potatoes, apples, beets, carrots, pumpkins, parsnips, taro root, and yucca.
In one embodiment, the produce consists of sweet potatoes. With further regard to the above challenges of processing produce such as sweet potatoes, the sugar profile of raw sweet potatoes (prior to treating steps described herein) should be noted. Though their name might imply otherwise, sweet potatoes are actually very different from white potatoes. Though they have in common the presence of reducing sugars—glucose, sucrose and fructose, the sugar profile of sweet potatoes versus white flesh potatoes is actually so different that sweet potatoes cannot be expected to behave in the same way as regular, or white, potatoes. Indeed, sweet potatoes pose more challenges in their processing due to the different sugar profile. The content of sucrose is roughly ten times higher in sweet potatoes than in white potatoes. By way of example, raw white chipping potatoes comprise an amount of about 0.1% reducing sugars and about 0.05% sucrose, whereas sweet potatoes contain between 1% to 6% sucrose. Sweet potatoes are also high in beta-amylase and high in glucose. Thus, processes involving dehydration to shelf stable moisture contents are more challenging for sweet potatoes. Color in sweet potatoes is not only subject to Maillard reactions but also further influenced by caramelization, a type of non-enzymatic browning, and is not fueled by the presence of amino acids unlike Maillard browning. Table 1 reflects the caramelization temperatures of the reducing sugars in sweet potatoes.
Brown pigments generated through the caramelization process can be controlled by the process described herein using a low temperature frying profile as described below. Using the process described herein, all sugars are reduced by roughly 50%, regardless of the particular variety of sweet potato. All sugars are affected equally and observe a proportional reduction using the method described herein.
Several embodiments for snack foods described herein and methods for making same will now be described with reference to the figures. Unless otherwise noted, like elements will be identified by identical numbers throughout all figures.
One embodiment of the method described herein will now be discussed with reference to
With reference to
After washing 10 but before any slicing, the whole raw produce is subjected to a pulsed electric field (“PEF”) 20 to enhance mass transfer. Electroporation enables the extraction of intracellular substances from the cells of the raw produce. The treatment chamber is arranged to receive the produce in solid phase, with a liquid transport carrier, past at least two electrodes, where the pulse generator is arranged to apply a PEF to a treatment space between the electrodes. In one embodiment, the process is continuous and raw whole produce is conveyed on a conveyor belt system to and through the PEF equipment, where the treatment space receiving the PEF is across a portion of a conveyor belt submerged in the liquid transport carrier. During test runs, a 30-kV unit was used at a repetition rate of 300 Hz at 12 feet/minute.
In one embodiment, the applied electric field is a pulsed electric field in the form of rectangular or (exponential) mono polar (bipolar) pulses. In one embodiment, the whole raw produce is subjected to an electric field strength of at least about 0.8 kV/cm. In one embodiment, the whole raw produce is subjected to an electric field strength of between about 0.8 to about 3.0 kV/cm. In one embodiment, the electric field strength ranges from about 1.1 to about 2.0 kV/cm. In one embodiment, the electric field strength ranges from about 1.5 to about 2.2 kV/cm. In one embodiment, about 1,000 pulses per second are applied. In one embodiment, the number of pulses applied is between about 70 to about 80.
Based on data on the frequency dependency of conductivity of intact and permeabilized plant tissues, a coefficient Zp, designated the disintegration index, was used to determine a suitable PEF treatment level. A Zp value, or disintegration index, of about 0.2 to about 0.35 is used herein and may be determined using the following formula:
Z
p=1−b*[(K′h−K′l)/Kh−Kl)];b=Kh/K′h;0≤Zp≤1
Where Kl, K′l=electrical conductivity of untreated and treated materials, respectively, in a low-frequency field (1-5 kHz); Kh, K′h=electrical conductivity of untreated and treated materials, respectively, in a high-frequency field (3-50 MHz). For intact cells, Zp=0; for total cell disintegration, Zp=1.
Raw produce is fed into the unit 70 below the upper conveyor belt 74, above the lower conveyor belt 76. Flights 75 on the upper conveyor belt 74 ensure that the produce remains below the predetermined water solution level 72 when the produce is moved by the upper conveyor belt 74 along the produce flow direction indicated by the arrow in
With reference back to
Immediately after slicing 30 (i.e., without any intervening step following slicing), the slices are subjected to a blanching step 40 in a turbulent environment comprising continuous agitation with water and air injection, free of mechanical agitation. In one embodiment, blanching is performed at temperatures of above about 145° F. for less than about 6 minutes. In one embodiment, blanching is performed at temperatures of above about 160° F. In one embodiment, blanching is performed at temperatures of above about 160° F. and about 180° F. In one embodiment, the blanching is performed for between about 2 to about 5.5 minutes. In one embodiment, the blanching is performed at between about 145° F. to about 195° F. for between about 1 to about 6 minutes. In one embodiment, the blanching is performed at between about 160° F. to about 180° F. for between about 3 to about 4 minutes. Dense produce comprising higher amounts of starch may require longer blanching times. In certain embodiments, the blancher selected may comprise a rotary blancher with a substantially sealed housing and a water supply for injecting water or steam into the blancher to heat the blancher and maintain the temperature at the set point temperature. As used herein, a turbulent environment is one configured to keep slices separated during blanching. Slice agitation may be performed, for example, using a screw within a water chamber comprising a water recirculation rate configured to recirculate water to keep slices separated. During test runs, a rotary drum blancher and a blower manufactured by Lyco Manufacturing Inc.® was used.
Following the required blanching period and temperature,
Finished fried product resulting from the above described method should comprise an oil content of about between about 30% and about 40%. In one embodiment, the finished fried product comprises an oil content of between about 32% and about 39%. In one embodiment, the finished fried product comprises an oil content of between about 35% and about 38%. In one embodiment, the finished fried product comprises an oil content of between about 38% and 39%.
Subjecting the produce to the method described herein results in a number of benefits. Across several varieties of tested sweet potatoes, the process described herein consistently delivered acrylamide levels below 250 ppb. Comparative data for different treatments can be seen in
In certain embodiments, ready-to-eat produce crisps made using the method and equipment described herein comprising or consisting of a coloring substantially equivalent to the coloring of the raw, untreated produce. In embodiments wherein the produce consists of sweet potatoes, for example, the resulting cooked crisps are sweet potato crisps substantially comprising a single color, the single color substantially the same as, or equivalent to, the natural color of the uncooked raw sweet potato. As used herein “substantially comprising a single color” means that only one single color within the base of the crisp is detectable to the naked, untrained eye. In some embodiments, though more than one gradation or shade of a color (i.e., hues) may be somewhat visible to the naked eye, the untrained eye will typically perceive a single color. For purposes of describing the favorable coloring that can only be achieved with sweet potatoes as described herein, the color is described under the standards set forth by the Hunter Lab color space.
Hunter L, a, b color space is a three-dimensional rectangular color space based on Opponent-Colors Theory. “L” indicates lightness and “a” and “b” indicate the color-opponent dimensions, further described below, based on nonlinearly compressed (e.g. CIE XYZ) coordinates. C.I. is a prefix for a listing of colorants listed according to Color Index Generic Names and Color Index Constitution Numbers as established by the Color Index International (CIE), which is a reference database jointly maintained by the Society of Dyers and Colourists and the American Association of Textile Chemists and Colorists. Thus, the color scale values are used to define the darkness/lightness of the resulting crisps.
All colors can be represented in L, a, b rectangular color space. In general, Hunter Color “L” scale values are chambers of light reflectance measurement, and the higher the value is, the lighter the color is since a lighter colored material reflects more light. Generally, the “L” axis denotes the level of white/black, or lightness, where 0 is black, 100 is white and 50 is middle gray. For the “a” (red-green) axis, positive values are red, negative values are green, and 0 is neutral. For the “b” (blue-yellow) axis, positive values are yellow, negative values are blue, and 0 is neutral. In particular, in the Hunter Color system the “L” scale contains 100 equal units of division. Absolute black is at the bottom of the scale (L=0) and absolute white is at the top of the scale (L=100). The color gray can be represented by “L” values between 0 and 100 at a and b values of zero.
In embodiments consisting of sweet potato, resulting crisps comprise an L-value of about 34 to about 65. In one embodiment, the L-value is about 44 to about 58. In another embodiment, the L-value is about 48 to about 53. In one embodiment, the a-value is about 12 to about 30. In one embodiment, the a-value is about 16 to about 25. In one embodiment, the a-value is about 18 to about 22. In one embodiment, the b-value is about 15 to about 35. Table 3 indicates color values as determined using a D25Lt Colorimeter manufactured by HunterLab. Oil content and moisture percentages are also indicated for the resulting crisps.
Unless otherwise specified, all percentages, parts and ratios as used herein refer to percentage, part, or ratio by weight of the total. Unless specifically set forth herein, the terms “a”, “an”, and “the” are not limited to one of such elements, but instead mean “at least one,” unless otherwise specified. The term “about” as used herein refers to the precise values as indicated as well as to values that are within statistical variations or measuring inaccuracies.
The methods disclosed herein may be suitably practiced in the absence of any element, limitation, or step that is not specifically disclosed herein. Similarly, specific snack food embodiments described herein may be obtained in the absence of any component not specifically described herein. Thus, the crisps described herein may consist of those listed components as described above.
Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, the range 1 to 10 also incorporates reference to all rational numbers within that range (i.e., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.
While this invention has been particularly shown and described with reference to several embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
