Method of preparing reduced fat foods

A method of preparing reduced fat foods is provided which employs a retrograded, hydrolyzed, heat-treated, and fragmented, amylose starch. Amylose is precipitated and hydrolyzed with acid or .alpha.-amylase, solubles are removed by a heat treatment and the resulting solids are then fragmented to form an aqueous dispersion that is useful in replacing fat in a variety of food formulations. The amylose can be derived from a native starch which contains amylose, e.g. common corn starch and high amylose corn starch, by gelatinizing the starch followed by precipitation of the amylose.

FIELD OF THE INVENTION 
This invention relates to food formulations in which at least a portion of 
the fat and/or oil is replaced by a carbohydrate. 
BACKGROUND OF THE INVENTION 
Lenchin et al. U.S. Pat. No. 4,510,166 discloses converted starches having 
a DE less than 5 and certain paste and gel characteristics which are used 
as a fat and/or oil replacement in various foods, including ice cream and 
mayonnaise. The converted starches are described as dextrins, 
acid-converted starches (fluidity starches), enzyme-converted starches and 
oxidized starches. It is also disclosed that if the converted starches are 
not rendered cold-water soluble by the conversion, they are pregelatinized 
prior to use or cooked during use. 
A product bulletin entitled "Paselli SA2; The Natural Alternative to Fats 
and Oils" (AVEBE b.a., Foxhol, Holland, Ref. No. 05.12.31.167 EF) 
discloses the use of a low-DE-hydrolysate (DE less than 3) made from 
potato starch as a replacement for fifty percent of the fat with an amount 
of the low-DE-potato starch hydrolysate plus water (starch hydrolysate at 
28% dry solids) equal to the amount of fat replaced. 
Richter et al. U.S. Pat. Nos. 3,962,465 and 3,986,890 disclose the use of 
thermoreversible gels of a starch hydrolysate (formed by enzymatic 
hydrolysis) as a substitute for fat in a variety of foods, including cake 
creams and fillings, mayonnaise and remoulades, cream cheeses and other 
cheese preparations, bread spreads, pastes, meat and sausage products, and 
whipped cream. 
Chiu U.S. Pat. No. 4,971,723 discloses partially debranched starch prepared 
by enzymatic hydrolysis of the .alpha.-1,6-D-glucosidic bonds of the 
starch, comprising amylopectin, partially debranched amylopectin and up to 
80% by weight, short chain amylose and that the partially debranched 
starch is useful in a variety of ways depending upon the degree of 
debranching. It is disclosed that a waxy maize starch (or other waxy 
starch) can be partially debranched (i.e. to 25% to 70% short chain 
amylose) to yield sufficient short chain amylose to form a thermally 
reversible gel in an aqueous starch suspension. It is further disclosed 
that the same degree of debranching of waxy starches is preferred for 
lending a fat-like, lubricating texture to an aqueous starch dispersion. 
PCT Publication No. WO 91/07106, published May 30, 1991, discloses a method 
of preparing a food grade, insoluble bulking agent from starch that is 
also disclosed to be useful as a bulking or texturizing agent in low-fat 
food formulations. The method of preparing the starch comprises a 
retrogradation process followed by enzymatic (e.g., .alpha.-amylase) or 
chemical (e.g., acid) hydrolysis of amorphous regions in the retrograded 
product. In this process, amylose is allowed to retrograde from a solution 
of gelatinized starch. The hydrolysis is then undertaken to reduce or 
eliminate amorphous regions in the retrograded product. 
SUMMARY OF THE INVENTION 
In one aspect, this invention relates to a method of preparing a 
heat-treated and fragmented amylose starch hydrolysate comprising: 
gelatinizing and retrograding an amylose starch in the presence of an 
aqueous medium to prepare an aqueous slurry of retrograded amylose; 
hydrolyzing said retrograded amylose to a degree sufficient to permit 
physical fragmentation to form a particle gel comprised of a minor amount 
of said retrograded amylose in a major amount of an aqueous medium; 
physically separating said hydrolyzed and retrograded amylose from an 
aqueous medium at an elevated temperature to remove a water-soluble 
hydrolysate fraction with said aqueous medium to produce a hydrolyzed and 
retrograded amylose free of water-soluble hydrolysate products; 
physically fragmenting a minor amount of said hydrolyzed and retrograded 
amylose essentially free of water-soluble hydrolysate products in a major 
amount of an aqueous medium to produce a particle gel thereof. 
In another aspect, this invention relates to a food formulation having a 
reduced level of fat and/or oil comprising a mixture of a foodstuff and a 
particle gel as a replacement for at least a substantial portion of the 
fat and/or oil of said foodstuff, said particle gel comprising a minor 
amount of a retrograded, hydrolyzed, heat-treated, and fragmented, amylose 
starch and a major amount of an aqueous liquid. 
In another aspect, this invention relates to a method of formulating a food 
containing a fat and/or oil ingredient comprising replacing at least a 
substantial portion of said fat and/or oil ingredient with a particle gel 
as a replacement for at least a substantial portion of the fat and/or oil 
of said foodstuff, said particle gel comprising a minor amount of a 
retrograded, hydrolyzed, heat-treated, and fragmented, amylose starch and 
a major amount of an aqueous liquid. 
By "retrograded, hydrolyzed, heat-treated, and fragmented, amylose starch" 
is meant a starch material comprised of amylose which has been subjected 
to gelatinization and retrogradation of the amylose followed by hydrolysis 
and heat-treatment (in the presence of water) to solubilize and remove 
water-soluble hydrolysate materials and then physically fragmented. The 
hydrolysis and fragmentation will be sufficient to produce a hydrolysate 
which will form an aqueous dispersion having the characteristics of a 
particle gel. The retrograded, hydrolyzed, heat-treated and fragmented 
amylose starch will preferably have only a minor amount (e.g. less than 
about 25%, preferably less than 10% and more preferably less than about 5% 
by weight on a dry solids basis) of hot-water solubles (e.g. the amount of 
solubles at 90.degree. C.). The amount of hot-water solubles can be 
determined as in PCT Publication No. WO 91/12728, published Sep. 5, 1991, 
at pages 55 and 56, but with the use of water maintained at an elevated 
temperature (e.g. 90.degree. C.). 
In another aspect, this invention relates to an aqueous dispersion useful 
as a replacement for fats and/or oils comprising a major amount by weight 
of water and a minor amount by weight of a retrograded, hydrolyzed, 
heat-treated, and fragmented amylose starch, the degree of hydrolysis and 
fragmentation of said starch being sufficient to form a particle gel of 
said dispersion. 
The terms "foodstuff" and "food", as used herein, are intended to broadly 
cover nutritional and/or functional materials that are ingested by humans 
in the course of consuming edible fare. The term "fats and/or oils" is 
intended to broadly cover edible lipids in general, specifically the fatty 
acid triglycerides commonly found in foods. The terms thus include solid 
fats, plastic shortenings, fluid oils (and fully or partially hydrogenated 
oils), and the like. Common fatty acid triglycerides include cottonseed 
oil, soybean oil, corn oil, peanut oil, canola oil, sesame oil, palm oil, 
palm kernel oil, menhaden oil, whale oil, lard, and tallow. The technology 
of fats and/or oils is described generally by T. H. Applewhite, "Fats and 
Fatty Oils", Encyclopedia of Chemical Technology, Vol. 9, pp. 795-831 
(Kirk-Othmer, eds., John Wiley & Sons, Inc., New York, N.Y., 3d ed., 
1980), the disclosure of which is incorporated by reference. 
The use of the terms "major" and "minor" in context together in this 
specification is meant to imply that the major component is present in a 
greater amount by weight than the minor component, and no more nor less 
should be inferred therefrom unless expressly noted otherwise in context. 
DETAILED DESCRIPTION OF THE INVENTION 
The retrograded, hydrolyzed, heat-treated, and fragmented amylose starch is 
made by the sequential steps of gelatinization, retrogradation, 
hydrolysis, heat treatment, and fragmentation of a starch material 
containing amylose. Starch is generally comprised of a highly-branched 
glucan having .alpha.-1,4 and .alpha.-1,6 linkages, denominated 
amylopectin, and a substantially linear glucan, having almost exclusively 
.alpha.-1,4 linkages, denominated amylose. Methods of determining the 
amounts of each are referenced in R. L. Whistler et al., Starch: Chemistry 
and Technology, pp. 25-35 (Academic Press, Inc., New York, N.Y., 1984), 
the disclosure of which is incorporated by reference. As used herein, the 
term "amylose" includes native amylose and, unless otherwise expressly 
noted in context, modified amylose. Examples of modified amylose include 
acid-modified amylose, enzyme-modified amylose (e.g. .alpha.-amylase, 
.beta.-amylase, isoamylase, or pullulanase) and chemically substituted 
amylose, provided the levels of chemical substitution (e.g. 
hydroxypropylation, crosslinking, etc. ) are insufficient to prevent 
precipitation and enzymatic hydrolysis of the amylose to the desired 
degree. Starches having a substantial proportion (i.e. at least 15% by 
weight) of amylose are preferred and examples of these include the common 
non-mutant starches of cereals, tubers and legumes, e.g. corn, wheat, 
rice, potato, tapioca, and pea. Preferred for use herein are starches 
derived from corn (Zea mays) such as common corn starch and high amylose 
corn starch, each of which are examples of starches containing greater 
than 15% amylose. Examples of such starches from high amylose corn include 
HI-SET.RTM. C and HYLON.TM. (each about 55% amylose by weight) and 
HYLON.TM. VII (about 70% amylose by weight), all available from National 
Starch and Chemical Corporation, Bridgewater, N.J. 
In certain embodiments, the starch is comprised of a major amount of 
amylose. In such embodiments, the starch employed is from a mutant variety 
of native starch which contains a major amount of amylose or is obtained 
by fractionation of amylose from a starch variety containing both amylose 
and amylopectin. Methods for the fractionation of amylose and amylopectin 
from native starch are disclosed in, for example, Etheridge U.S. Pat. No. 
3,067,067. 
If the starch chosen as a starting material is not in pre-gelatinized or 
instant form, the starch must be gelatinized or pasted prior to 
precipitation of the amylose. The gelatinization or pasting process 
disrupts, at least in substantial part, the associative bonding of the 
starch molecules in the starch granule. This permits the amylose to 
associate and precipitate. This disruption is accomplished by heating a 
slurry of the starch to a sufficient temperature for a sufficient length 
of time depending upon the inherent resistance of the particular starch to 
gelatinization and the amount of moisture present in the slurry. The 
slurry will typically be comprised of a major amount of water (i.e. at 
least 50% by weight) and a minor amount of the starch starting material 
(i.e. less than about 50% by weight). Preferably, the starch slurry will 
contain at least about 5% starch, typically between about 7% to about 10% 
starch. The pH of the slurry will generally be substantially neutral, i.e. 
from about 3.5 to about 9 and more preferably from about 6 to 8, to 
minimize hydrolysis of the starch molecules. The time, temperature, slurry 
solids, and pH should be optimized to gelatinize the starch, yet minimize 
hydrolysis of the starch. 
The appropriate temperature, pressure and period of treatment needed to 
provide a starch paste is preferably obtained by processing aqueous starch 
slurries in equipment commonly known in the art as steam injection heaters 
or jet cookers. In such equipment, superatmospheric steam is injected and 
mixed with a water slurry of starch in a throat section of a jet. Upon 
contact with the injected steam, the starch granules are uniformly and 
thermally treated under turbulent conditions whereupon the starch granules 
are gelatinized and solubilized. Examples of steam injection heaters 
wherein the temperature, pressure and feed rate can be regulated to 
provide the desired starch pastes are disclosed in U.S. Pat. Nos. 
3,197,337; 3,219,483; and 3,133,836. More uniformly solubilized starch 
pastes are obtained by use of the steam injection heater in combination 
with a holding zone such as coiled tubing or a pressurized tank 
constructed to minimize liquid channeling. Other pasting equipment, e.g. 
heat exchangers, homogenizers, cookers, votators, sizeometer cookers, 
kettle cookers, etc., may be employed provided the pasting conditions can 
be adequately maintained. 
The starch solution may also be treated to remove impurities therefrom. 
Treatment with, for example, activated carbon will remove residual 
proteins and lipids that may contribute to off-flavors and/or colors. 
The gelatinized starch is then optionally treated with a debranching 
enzyme, i.e. an enzyme capable of hydrolyzing the 1,6-glucosidic bond of 
amylopectin without significant capability of hydrolyzing the 
1,4-glucosidic bond. Enzymes from a variety of sources are capable of 
debranching amylopectin. U.S. Pat. No. 3,370,840 (Sugimoto et al.) 
describes sources of debranching enzymes, the disclosure of which is 
incorporated herein by reference. Examples of useful enzymes include 
pullulanases derived from bacteria of the genus Aerobacter (e.g. E.C. 
3.2.1.41 pullulan 6-glucanohydrolase) and isoamylases derived from 
bacteria of the genus Pseudomonas (e.g. E.C. 3.2.1.68 glycogen 
6-glucanohydrolase). Particularly useful enzymes include thermostable 
enzymes, e.g. thermostable pullulanases as disclosed in PCT Publ. No. WO 
92/02614, published Feb. 20, 1992, the disclosure of which is incorporated 
by reference, and which are obtained from members of the genus Pyrococcus. 
The debranching enzyme may be in solution during debranching or it may be 
immobilized on a solid support. 
The debranching enzyme preparation should be as specific as possible for 
the hydrolysis of the 1,6-glucosidic bond of amylopectin and amylose. 
Thus, the enzyme preparation, if it contains a mixture of enzymes, is 
preferably essentially free of enzymes capable of hydrolyzing 
.alpha.-1,4-glucosidic bonds. Minimizing hydrolysis of 
.alpha.-1,4-glucosidic bonds will help to minimize the amounts of dextrose 
and soluble oligomers produced during debranching. Because these soluble 
saccharities are not believed to contribute to the functionality of the 
debranched material, minimizing their production will enhance the yield of 
functional material. 
The debranching enzyme is allowed to act upon the solubilized starch 
containing amylopectin. The optimum concentration of enzyme and substrate 
in the debranching medium will, in general, depend upon the level of 
activity of the enzyme which, in turn, will vary depending upon the enzyme 
source, enzyme supplier, and the concentration of the enzyme in commercial 
batches. When the isoamylase E.C. 3.2.1.68, derived from Pseudomonas 
amyloderamosa, available from Sigma Chemical Co., St. Louis, Mo., is 
employed, typical conditions include the treatment of a starch solution at 
5% to 30% by weight starch solids with about 50 units of enzyme, per gram 
of starch, for a period of about 48 hours to obtain substantially complete 
debranching. 
The optimum pH and temperature of the debranching medium will also depend 
upon the choice of enzyme. The debranching medium may, in addition to the 
water used to solubilize the starch, contain buffers to ensure that the pH 
will be maintained at an optimum level throughout the debranching. 
Examples of useful buffers include acetates, citrates, and the salts of 
other weak acids. With the isoamylase described above, the pH is 
preferably maintained at about 4.0 to 5.0 and the temperature from about 
40.degree. C. to about 50.degree. C. With the thermostable pullulanase 
described above, the pH is preferably maintained between 5 and 7 and the 
optimum temperature should be between 85.degree. C. and 115.degree. C. 
The debranching is allowed to proceed until the desired degree of 
debranching has been obtained. The precise degree of debranching needed to 
obtain the desired particle gel of the debranched amylopectin starch may 
vary depending upon the source of the starch and the precise properties 
desired in the resulting gel. Preferably, the degree of debranching is 
sufficient to convert more than about 80% of the amylopectin in the starch 
to short chain amylose and, more preferably, at least about 90% of the 
amylopectin. 
In preferred embodiments, essentially all of the amylopectin is converted 
to short chain amylose. The amount of short chain amylose can be measured 
by gel permeation chromatography as set forth in U.S. Pat. No. 4,971,723, 
wherein short chain amylose is calculated from the relative area of the 
peak obtained within the molecular weight range of 500 to 20,000. Thus, 
preferably less than 20% of the amylopectin that was originally present 
will be present as molecular species having a molecular weight in excess 
of 20,000 g/mol, and most preferably, essentially no amylopectin having a 
molecular weight in excess of 20,000 g/mol will remain. (It should be 
noted that if amylose is present, at least a portion thereof may be 
debranched to produce molecules above the 20,000 g/mol cut-off and 
molecules below the 20,000 g/mol cut-off. To measure how much of the 
material eluting between 500 g/mol and 20,000 g/mol is debranched 
amylopectin and how much is debranched amylose, it may be necessary to 
fractionate the starting starch into its amylose and amylopectin fractions 
and then debranch and elute each fraction separately.) 
The solution of debranched starch may also be treated to remove impurities 
therefrom. Treatment with, for example, activated carbon will remove 
residual proteins and lipids that may contribute to off-flavors and/or 
colors. 
The solution of gelatinized, and optionally debranched, starch is then 
allowed to form a precipitate of retrograded starch. Generally, the 
solution will be cooled from the temperature at which the starch is pasted 
to reduce the solubility of the gelatinized starch therein. The solution 
will typically be held at elevated temperature (e.g. 65.degree. C. to 
90.degree. C.) until substantial equilibrium is achieved between the 
supernatant and the precipitate. The precipitate can be isolated from the 
supernatant, e.g. by centrifugation, prior to fragmentation, but isolation 
from the supernatant is not necessary to form a useful product. 
Heating (e.g. to about 70.degree. C.) of the particles while in contact 
with the aqueous medium to dissolve at least a portion of the mass of the 
particles and then cooling of the suspension/solution can also be employed 
in forming the particle gel of this invention. This heating to an elevated 
temperature and then reformation of the particles tends to make the 
particles resistant to melting or dissolving when an aqueous dispersion of 
the particles is exposed to heat in processing, e.g. in a pasteurization 
step. In general, the higher the temperature to which the particles in the 
liquid medium are heated (and thus the greater the amount of precipitate 
that is redissolved), the higher the temperature at which the resulting 
aqueous dispersion of the particles will be stable. Repetition of the 
dissolving and reformation may improve the temperature stability of the 
resulting aqueous dispersion. 
It is also advantageous to heat the precipitate to redissolve a substantial 
portion of the low melting polysaccharides and then treat the heated 
suspension of precipitate with acid or enzyme to hydrolyze soluble 
polysaccharides in the solution. (It may also be advantageous to filter 
the slurry while hot to remove soluble polysaccharides or their 
hydrolysates.) The dissolving and reprecipitation steps alone improve the 
stability of the aqueous dispersion by increasing the amount of the 
fragmented precipitate which remains as insoluble fragments in an aqueous 
dispersion that is exposed to heat. Further, a slow rate of heating and/or 
cooling (e.g. from about 0.005.degree. C./min. to about 0.5.degree. 
C./min. for each) may be advantageous. However, the remaining soluble 
fraction of the precipitate can associate to form relatively large 
particles that are present in the precipitate after fragmentation and that 
can contribute a "chalky" or "gritty" texture to the dispersion. Treatment 
of the heated suspension/solution of the precipitate with acid or enzyme 
to hydrolyze a substantial portion of the soluble fraction can reduce or 
eliminate such large particles. Typical treatment conditions will involve 
mild hydrolysis catalyzed by acid, e.g. in a solution of 0.1 N HCl for one 
hour, or, preferably, by enzyme, e.g. .alpha.-amylase. 
The precipitated amylose is then hydrolyzed with an acid (e.g. a mineral 
acid such as hydrochloric acid or sulfuric acid) or treated with an 
.alpha.-amylase enzyme, i.e. an endo-enzyme capable of hydrolyzing the 
1,4-glucosidic bond of amylose and amylopectin to yield products having an 
.alpha. configuration. The acid or enzyme is allowed to act upon the 
precipitated amylose and thereby hydrolyze those regions in the 
precipitate that are susceptible to hydrolysis. The optimum concentration 
of acid or enzyme and substrate in the hydrolysis medium will, in general, 
depend upon the level of activity of the acid enzyme which, in turn, will 
vary depending upon the acid strength or enzyme source, enzyme supplier 
and the concentration of the enzyme in commercial batches. Typical 
treatment conditions will involve mild hydrolysis catalyzed by acid, e.g. 
in a solution of 0.1 N HCl for one hour, or, preferably, by enzyme, e.g. 
.alpha.-amylase. 
The .alpha.-amylase can be from a variety of sources. Common sources of 
.alpha.-amylase are bacterial, e.g. Bacillus subtilis, or fungal, e.g. 
Aspergillus oryzae, or mammalian, e.g. human salivary, porcine pancreatic, 
etc. The optimum pH and temperature of the hydrolysis medium will also 
depend upon the choice of enzyme. The hydrolysis medium may, in addition 
to the water used in the hydrolysis of the starch, contain buffers to 
ensure that the pH will be maintained at an optimum level throughout the 
hydrolysis. Examples of useful buffers include acetates, citrates, 
phosphates, and the salts of other weak acids. With porcine pancreatic 
.alpha.-amylase, the pH is preferably maintained at about 6.0 to 8.0 and 
the temperature from about 20.degree. C. to about 30.degree. C. 
The hydrolysis is allowed to proceed until the desired degree of hydrolysis 
has been obtained. The precise degree of hydrolysis needed to obtain the 
desired particle gel of the fragmented amylose starch may vary depending 
upon the source of the starch and the precise properties desired in the 
resulting gel. Typically, the degree of hydrolysis will be such that 
fragmentation of the product will yield a gel that exhibits a transition 
from a region of substantially constant dynamic elastic modulus (G') 
versus shear strain to a region of decreasing G' versus shear strain, said 
transition being at a shear strain of less than about 50 millistrain, and 
preferably less than about 10 millistrain. The transition indicates 
fracture of the particle network within the particle gel and is typically 
a sharp transition. The dynamic elastic modulus can be measured with a 
Bohlin model VOR Rheometer, from Bohlin Rheologi, Inc., East Brunswick, 
N.J. 
The hydrolysis medium is essentially aqueous. Generally, it will contain no 
more than a trace, if any, of organic solvents (e.g. ethanol). Organic 
solvents may react with the saccharide by-products (e.g. dextrose to form 
at least traces of ethyl glucoside), may otherwise affect the hydrolysis 
reaction (e.g. solvent effects) and/or may contaminate the starch 
hydrolysate product. 
The progress of the hydrolysis may be followed by taking small samples of 
slurry from an in-progress batch of the starch hydrolysate, adjusting the 
pH of the slurry (e.g. to 4-5), isolating the solid starch hydrolysate 
residue from the slurry sample, and mechanically disintegrating the 
residue under the conditions intended for the batch as a whole. The yield 
stress of a 20% aqueous dispersion can then be measured to determine if 
the acid-hydrolysis has progressed to a desired degree (typically from 
about 100 pascals to about 3,000 pascals, preferably at least about 300 
pascals). Also, samples of insoluble residue can be isolated for a 
determination of peak molecular weight (or weight average molecular 
weight) by gel permeation chromatography or of supernatant for dextrose 
content and the results used as a measure of the degree of hydrolysis; 
both molecular weight (particularly M.sub.w) and dextrose content should 
correlate well with yield stress of the resulting starch hydrolysate upon 
fragmentation for a given set of reaction conditions (i.e. acid 
concentration, starch solids concentration, and hydrolysis time and 
temperature). 
After the desired degree of hydrolysis is obtained, the acid is neutralized 
or the .alpha.-amylase enzyme in solution is deactivated, e.g. by heating 
to denature the enzyme. The hydrolysis medium may be concentrated by 
removal of water therefrom, e.g. by evaporation, to facilitate 
precipitation. 
If the amylose starch chosen as a starting material is relatively low in 
amylose content, e.g. less than 40% amylose, it may be useful to stage the 
hydrolysis reaction. This staging will involve an initial hydrolysis 
period at less than 70.degree. C., e.g. at 60.degree., for a time 
sufficient to hydrolyze and leach from the retrograded material a 
significant amount of amorphous and low melting starch. The initial 
hydrolysis period is then followed by a second hydrolysis period during 
which the temperature of the reaction slurry is maintained above 
70.degree. C., preferably above 90.degree. C. The starch hydrolysate from 
the initial period can be isolated from the reaction slurry and then 
reslurried for the second hydrolysis period, but there is no need for such 
isolation between the stages. 
As an alternative to hydrolysis at above 90.degree. C., the starch can be 
hydrolyzed at temperatures below 70.degree. C. and then heated, in aqueous 
slurry at a substantially neutral pH, to a temperature above 90.degree. C. 
for a time sufficient to raise the melting onset temperature to at least 
90.degree. C. when measured at 20% starch hydrolysate solids. The starch 
hydrolysate can be isolated from the reaction slurry and reslurried for 
such treatment or the reaction slurry, after neutralization, can simply be 
heated above 90.degree. C. Such heat treatment will typically involve 
holding a slurry comprised of a major amount of water and a minor amount 
of starch hydrolysate at a substantially neutral pH, e.g. a pH of about 
3-8, preferably about 4-7, and at a temperature between about 90.degree. 
C. and about 130.degree. C. for about 1/2 hour to about 3 hours. The 
resulting starch hydrolysate can then be isolated as described more fully 
below. 
The starch hydrolysis product of the slurry is isolated as the solid phase 
residue by separation thereof from the aqueous phase of the slurry. 
Techniques for such isolation include filtration (e.g. horizontal belt 
filtering), centrifugation (e.g. disk, decanter or solid bowl), 
sedimentation, and other suitable dewatering operations. It is 
advantageous to maintain the slurry at an elevated temperature (e.g. 
90.degree. to 130.degree. C.) during isolation to keep the undesirable 
saccharides in solution. It should be noted that a solid bowl centrifuge 
has been found to be one of two most practical means of isolating the 
solid phase residue by sedimentation. 
The principles .and modes of operation of imperforate bowl centrifuges are 
described by A. C. Lavanchy and F. W. Keith, "Centrifugal Separation", 
Encyclopedia of Chemical Technology, Vol. 5, pp. 194-233 (Kirk-Othmer, 
eds., John Wiley & Sons, Inc., New York, N.Y., 3d ed., 1979) and P. A. 
Schweitzer, Handbook of Separation Techniques for Chemical Engineers, pp. 
4-60 to 4-88 (McGraw Hill, New York, N.Y., 1988), the disclosures of each 
of which are incorporated herein. (It should be noted that Schweitzer uses 
the term "Solid-Wall Basket Centrifuge".) 
It has been found that microfiltration is an effective means of separating 
an insoluble starch hydrolysate residue from an aqueous slurry thereof 
which also contains a relatively large amount of dissolved species, e.g. 
salt and saccharides. Microfiltration is described generally in D. R. Paul 
and G. Morel, "Membrane Technology", Encyclopedia of Chemical Technology, 
Vol. 15, pp. 92-131 (Kirk-Othmer, eds., John Wiley & Sons, Inc., New York, 
N.Y., 3d ed., 1981), the disclosure of which is incorporated herein by 
reference. 
Typically, a liquid including small dissolved molecules is forced through a 
porous membrane. Large dissolved molecules, colloids and suspended solids 
that cannot pass through the pores are retained. Components retained by 
the membrane are collectively referred to as a concentrate or retentate. 
Components which traverse the membrane are referred to collectively as 
filtrate or permeate. Diafiltration is a microfiltration process in which 
the retentate is further purified or the permeable solids are extracted 
further by the addition of water to the retentate. This process is 
analagous to washing of a conventional filter cake. The use of 
microfiltration removes salts formed by the neutralization of the alkaline 
solution and other molecular species small enough to pass through the 
membrane. 
Ultrafiltration is generally described and discussed by P. R. Klinkowski, 
"Ultrafiltration", Encyclopedia of Chemical Technology, Vol. 23, pp. 
439-461 (Kirk-Othmer, eds., John Wiley & Sons, New York, N.Y., 3d ed., 
1983), the disclosure of which is incorporated by reference herein. 
Ultrafiltration is a pressure-driven filtration on a molecular scale. The 
porous membrane typically has a pore size ranging from 0.005 to 20 
micrometers (or microns). While a distinction is often made in the 
separation art between ultrafiltration (pore size range of 2 to 20 
nanometers) and microfiltration (pore size greater than 20 nanometers), 
the terms will be used interchangeably herein unless expressly noted 
otherwise. 
The acid in the slurry can be neutralized either before or after isolation 
of the hydrolysate. Any food grade alkali (e.g. sodium hydroxide, soda 
ash, potassium hydroxide, etc.) can be used to neutralize the slurry, 
preferably to a pH of from about 4 to about 5. However, it may be 
advantageous (in terms of obtaining a desirably bland flavor for the 
hydrolysate) to (i) only partially neutralize the slurry to a weakly 
acidic pH (e.g. from about 2.0 to about 3.5) and (ii) then hold the slurry 
at a moderately elevated temperature (e.g. 25.degree. C. to 75.degree. C.) 
for a short period of time (e.g. 15 minutes to 24 hours), prior to 
isolation, followed by washing and then neutralization of the solid 
hydrolysate residue to a substantially neutral pH (e.g. about 4.5 to about 
5.0). This acid washing of the starch hydrolysate is particularly 
advantageous when employed in the context of microfiltration of the starch 
hydrolysate slurry Using a ceramic microfiltration membrane contained 
within an acid resistant (e.g. polyvinyl chloride) housing. 
By "microporous ceramic membrane" is meant any ceramic layer (including 
"supported layer articles") having micropores and sufficient structural 
integrity to withstand the pressure needed to isolate the insoluble starch 
hydrolysate residue from the liquid phase of the aqueous slurry over a 
desired period of time (e.g. from 15 minutes to 24 hours). It is believed 
that the high pressure used to isolate the insoluble starch hydrolysate 
residue creates turbulent flow at the membrane's surface which prevents 
small particles in the slurry from "blinding off" the pores of the 
membrane (as has been observed with conventional filtration equipment as 
discussed below). 
A typical microporous ceramic membrane is comprised of a microporous 
ceramic article having at least one macroscopic passage therethrough 
(typically a cylindrical article having cylindrical passages) 
substantially parallel to the axis of symmetry of the cylindrical article. 
While the article may be "microporous" itself, the ceramic cylinder may 
act principally as a support (i.e. in a "supported layer article") for a 
microporous layer (or layers with regard to multi-passage articles) which 
covers the surfaces defined by the passages through the ceramic article. 
The porosity of the ceramic article, and any microporous layer associated 
therewith as described above, can be varied as desired, with the pore size 
of any such layer being smaller than that of the article. In typical 
operation, such a ceramic filter element (i.e. cylindrical and microporous 
ceramic article) is contained in hollow cylindrical housing and slurry is 
fed into the passages under pressure through a feed manifold that prevents 
leakage into the housing. The exit of the isolated starch hydrolysate 
residue from the passages at the other end of the ceramic filter element 
is controlled by an exit manifold which also prevents leakage into the 
housing where the filtrate or permeate is contained. Ceramic filter 
elements and their use are described in "Solve Tough Process Filtration 
Problems with Ceraflo Ceramic Systems", a technical bulletin, Lit. No. 
SD113, 2/89 89-418, published (1989) by Millipore Corporation, Bedford, 
Mass., the disclosure of which is incorporated by reference. 
The isolated amylose hydrolysate is typically dried (e.g. to a low moisture 
content, typically 3-12%) after isolation to allow for handling and 
storage prior to further processing. Examples of drying techniques include 
spray drying, flash drying, tray drying, belt drying, and sonic drying. 
The dried hydrolysate may be hygroscopic. Thus, some rehydration during 
handling and storage may occur. Depending upon the precise composition of 
the hydrolysate and the conditions (including length of time) of storage, 
steps to maintain the moisture at a low content may be necessary (e.g. 
moisture barrier packaging and/or control of humidity in the storage 
environment). If the moisture content is allowed to rise too far (e.g. 
greater than about 20%, or possibly greater than 15%), bulk handling 
problems and/or microbiological stability problems might arise. 
The retrograded, hydrolyzed, and heat-treated amylose starch is subjected 
to a physical fragmentation as by mechanical disintegration, i.e. 
fragmented. The degree of fragmentation will be sufficient to cause the 
material to form a particle gel in an aqueous medium. The mechanical 
disintegration of the hydrolysate may be carried out in several ways, as 
by subjecting it to attrition in a mill, or to a high speed shearing 
action, or to the action of high pressures. Disintegration is generally 
carried out in the presence of a major amount by weight of a liquid 
medium, preferably water. Although tap water is the preferred liquid 
medium for the dispersion of fragmented amylose starch hydrolysate, other 
liquids are suitable provided sufficient water is present to hydrate the 
fragmented amylose starch hydrolysate and, thus, result in a dispersion 
having the characteristics of a particle gel. Sugar solutions, polyols, of 
which glycerol is an example, alcohols, particularly ethanol, isopropanol, 
and the like, are good examples of suitable liquids that can be in 
admixture with water in the liquid medium. Typically, however, the amylose 
starch hydrolysate will be physically fragmented in potable water. 
The mechanical disintegration is preferably accomplished by subjecting an 
aqueous dispersion of the hydrolysate to high shear, e.g. in a Waring 
blender or a homogenizer such as that disclosed in U.S. Pat. No. 4,533,254 
(Cook et al.) and commercially available as a MICROFLUIDIZER.TM. from 
Microfluidics Corporation, Newton, Mass., or a homogenizer such as the 
RANNIE.TM. high pressure laboratory homogenizer, Model Mini-lab, type 8.30 
H, APV Rannie, Minneapolis, Minn. Homogenizers useful in forming 
suspensions or emulsions are described generally by H. Reuter, 
"Homogenization", Encyclopedia of Food Science, pp. 374-376, (M. S. 
Peterson and A. H. Johnson, eds., AVI Publ. Co., Westport, Conn., 1978), 
L. H. Rees and W. D. Pandolfe, "Homogenizers", Encyclopedia of Food 
Engineering, pp. 467-472 (C. W. Hall et al., eds., AVI Publ. Co., 
Westport, Conn., 1986), and W. C. Griffin, "Emulsions", Encyclopedia of 
Chemical Technology, Vol. 8, pp. 900-930 (Kirk-Othmer, eds., John Wiley & 
Sons, Inc., New York, N.Y., 3d ed., 1979), the disclosures of which are 
incorporated herein by reference. 
The temperature of the amylose starch hydrolysate during the fragmentation 
step should be maintained below the temperature at which a major portion 
of the hydrolysate will dissolve in the aqueous medium. However, the heat 
treatment to remove water-soluble hydrolysate material should make the 
remaining retrograded material relatively insensitive to elevated 
temperatures. Thus, it will probably not be necessary to cool the material 
during disintegration. Whatever method is used, the disintegration is 
carried out to such an extent that the resulting finely-divided product is 
characterized by its ability to form a particle gel in the liquid medium 
in which it is attrited or in which it is subsequently dispersed. 
The amylose starch hydrolysate particles which make up the particle gel can 
be analyzed in a variety of ways. Rheological measurements can be made to 
determine the theological characteristics of the resulting dispersion. 
Typically, the aqueous dispersion of amylose starch hydrolysate particles 
will exhibit a transition in dynamic elastic modulus (G') versus shear 
strain at less than about 50 millistrain, and preferably less than about 
10 millistrain, said transition being from a substantially constant G' 
versus shear strain to a decreasing G' versus shear strain. The transition 
indicates fracture of the particle network within the particle gel and is 
typically a sharp transition. 
It should also be noted that mechanical disintegration may be sufficient to 
produce an aqueous dispersion having the desired particle gel 
characteristics, but still leave a sufficient number of particles of 
sufficient size to exhibit a "particulate" or "chalky" mouthfeel when 
ingested. Such chalkiness can be reduced by the mild hydrolysis discussed 
above or by reducing the particle size of the starch hydrolysate before, 
during or after mechanical disintegration so that substantially all 
(typically at least about 95%, preferably at least 99%) of the hydrolysate 
will pass a U.S. #325 mesh sieve (i.e. substantially all particles are 
less than 45 microns). An example of a milling device suitable for such 
size reduction is a TROST.TM. Air Impact Mill from Gatlock, Inc., Newton, 
Pa. 
The use of the retrograded, hydrolyzed, heat-treated and fragmented, 
amylose starch hydrolysate allows for the replacement of a substantial 
portion (e.g. from 10% to 100% by weight) of the fat and/or oil in a food 
formulation. The precise level of replacement that is possible without 
significantly decreasing the organoleptic quality of the food will 
generally vary with the type of food. For example, in a French-style salad 
dressing, it is generally possible to completely replace the oil component 
that is normally present. In other types of foods, e.g. frostings, icings, 
cream fillings, ice cream, margarine, etc., a major amount of the fat 
and/or oil (e.g. about 50% to about 80%) can be replaced with little 
effect on the organoleptic desirability of the food. Examples of typical 
foods in which fat and/or oil can be replaced include frostings (e.g. 
icings, glazes, etc.), creme fillings, frozen desserts (e.g. ice milk, 
sherbets, etc. ), dressings (e.g. pourable or spoonable salad and/or 
sandwich dressings), meat products (e.g. sausages, processed meats, etc.), 
cheese products (e.g. cheese spreads, processed cheese foods), margarine, 
fruit butters, other imitation dairy products, puddings (e.g. mousse 
desserts), candy (e.g. chocolates, nougats, etc. ), and sauces, toppings, 
syrups and so on. 
Generally, it will be desirable to remove sufficient fat from a given food 
formulation to achieve a reduction in calories of at least one-third per 
customary serving or make a label claim of "cholesterol-free". (In this 
regard, see, for example, the list of standard serving sizes for various 
foods published in Food Labelling; Serving Sizes, 55 Fed. Reg. 29517 
(1990) (to be codified at 21 C.F.R. 101.12), the disclosure of which is 
incorporated herein by reference, and the restrictions on labeling 
"cholesterol-free" at Food Labelling; Definitions of the Terms Cholesterol 
Free, Low Cholesterol and Reduced Cholesterol, 55 Fed. Reg. 29456 (1990)). 
It should also be noted that the fat removed from a particular formulation 
may be replaced with an equal amount by weight of an aqueous dispersion of 
fragmented amylose starch hydrolysate, but that such equality may not be 
necessary or desirable in all instances. Further, it may be desirable to 
remove fat and add another ingredient (e.g. a gum, polydextrose, a 
protein, etc.) along with the aqueous dispersion of starch hydrolysate. 
While this invention is generally directed to the replacement of fat and/or 
oil in a food formulation, it is of course within the contemplation of 
this invention that a fragmented, amylose starch hydrolysate will be used 
in an entirely new formulation to which it contributes fat-like 
organoleptic qualities but is not, in the strictest sense, replacing a 
pre-existing fat or oil ingredient. Moreover, it is contemplated that the 
fragmented amylose starch hydrolysate will have utility as a thickener, 
bodying agent, or the like in foods that normally do not have a 
significant fat or oil component. 
In general, the fragmented amylose starch hydrolysate will be incorporated 
into the food as an aqueous dispersion, typically comprised of a major 
amount (i.e. greater than 50% by weight) of water or other liquid medium 
and a minor amount (i.e. less than 50% by weight, typically 10% to 40%) of 
amylose starch hydrolysate solids. Alternatively, the isolated amylose 
starch hydrolysate can be mixed with the food along with water and then 
subjected to disintegration in those instances when the other ingredients 
of the food are capable of withstanding the condition of disintegration, 
e.g. a salad dressing or imitation sour cream. 
It is contemplated that commercial production and use may involve 
hydrolysis, mechanical disintegration, and drying (e.g. spray drying) of 
the fragmented starch hydrolysate to produce an item of commerce. This 
item of commerce will then be purchased by a food processor for use as an 
ingredient. To incorporate the dried, fragmented, amylose starch 
hydrolysate into a food product, it may be useful and/or necessary to 
further mechanically disintegrate the starch hydrolysate while dispersing 
it into the foodstuff in which it will be employed. However, the 
techniques employed for such mechanical disintegration should not need to 
be nearly as vigorous as the original mechanical disintegration prior to 
drying. 
As noted above, the terms "food" and "foodstuffs" are intended broadly, as 
relating to both nutritional and/or functional food ingredients. It is 
contemplated that one or more food ingredients may be mixed with the 
aqueous dispersion of fragmented amylose starch hydrolysate, or even dry 
mixed with the hydrolysate prior to mechanical disintegration. 
Among the food ingredients which may be included in the food formulations 
of this invention are flavors, thickeners (e.g. starches and hydrophilic 
colloids), nutrients (e.g. carbohydrates, proteins, lipids, etc.), 
antioxidants, antimicrobial agents, non-fat milk solids, egg solids, 
acidulants, and so on. 
Hydrophilic colloids can include natural gum material such as xanthan gum, 
gum tragacanth, locust bean gum, guar gum, elgin, elginares, gelatin, 
Irish moss, pectin, gum arabic, gum ghatti, gum karaya and plant 
hemicelluloses, e.g. corn hull gum. Synthetic gums such as water-soluble 
salts of carboxymethyl cellulose can also be used. Starches can also be 
added to the food. Examples of suitable starches include corn, waxy maize, 
wheat, rice, potato, and tapioca starches. 
Non-fat milk solids which can be used in the compositions of this invention 
are the solids of skim milk and include proteins, mineral matter and milk 
sugar. Other proteins such as casein, sodium caseinate, calcium caseinate, 
modified casein, sweet dairy whey, modified whey, and whey protein 
concentrate can also be used herein. 
For many foods, it is accepted practice for the user to add the required 
amount of eggs in the course of preparation and this practice may be 
followed just as well herein. If desired, however, the inclusion of egg 
solids, in particular, egg albumen and dried yolk, in the food are 
allowable alternatives. Soy isolates may also be used herein in place of 
the egg albumen. 
Dry or liquid flavoring agents may be added to the formulation. These 
include cocoa, vanilla, chocolate, coconut, peppermint, pineapple, cherry, 
nuts, spices, salts, flavor enhancers, among others. 
Acidulants commonly added to foods include lactic acid, citric acid, 
tartaric acid, malic acid, acetic acid, phosphoric acid, and hydrochloric 
acid. 
Generally, the other components of the various types of food formulations 
will be conventional, although precise amounts of individual components 
and the presence of some of the conventional components may well be 
unconventional in a given formulation. For example, the conventional other 
components for foods such as frozen desserts and dressings, are described 
in European Patent Publication No. 0 340 035, published Nov. 2, 1989 (the 
pertinent disclosure of which is incorporated herein by reference), and 
the components and processing of table spreads is disclosed in Lowery U.S. 
Pat. No. 4,869,919, the disclosure of which is incorporated by reference. 
A particularly advantageous use of the fragmented starch hydrolysates 
described herein may be the use thereof to replace a portion of the 
shortening used in a layered pastry article. In layered pastry articles 
(Danish, croissants, etc.), layers of a bread dough are assembled with a 
"roll-in" placed between the layers. The roll-in commonly contains a 
"shortening" (i.e. a fat and/or oil component) from an animal (e.g. 
butter) or vegetable (e.g. partially hydrogenated soybean oil) source. The 
assembled article, optionally containing a filling or topping, is then 
baked to form a finished pastry. At least a portion of the shortening of 
an otherwise conventional roll-in can be replaced with an aqueous 
dispersion of fragmented, amylose hydrolysate, preferably in admixture 
with an emulsifier (e.g. mono-and/or di-glycerides), and used to make a 
layered pastry. 
The following examples will illustrate the invention and variations thereof 
within the scope and spirit of the invention will be apparent therefrom. 
All parts, percentages, ratios and the like are by weight throughout this 
specification and the appended claims, unless otherwise noted in context.

EXAMPLES 
EXAMPLE 1 
High amylose starch (HI-SET C, National Starch and Chemical Co.) was first 
solubilized at 7% dry solids by weight by heating a slurry thereof in 
water in a pressure vessel to about 150.degree. C. The resulting solution 
was cooled to room temperature (about 25.degree. C.) and allowed to stir 
for 20 hours during which time a thick mass of crystals precipitated. Acid 
(HCl in an amount of 0.45-0.46 meq/gm of slurry) was added and hydrolysis 
of the crystals in the slurry was carried out at 70.degree. C. for the 
time indicated below. The insoluble product was isolated by centrifugation 
with a water wash (at room temperature) to remove low molecular weight 
solubles. The results of two separate replicates hydrolyzed for different 
time periods are shown below, where Mw is weight average molecular weight 
by gel permeation chromatography. All values in the table below can be 
determined as in PCT Publication No. WO 91/12728, published Sep. 5, 1991. 
______________________________________ 
Time Mw Insolubles (wt %) 
Yield Stress (Pas) 
______________________________________ 
6 hr 8,581 22.1 910 
4 hr 10,203 32.6 1165 
______________________________________ 
The products were fragmented at 20% dry starch hydrolysate solids at 8,000 
psi in a Microfluidizer homogenizer at 60.degree. C. The DSC endotherm of 
the 6 hour product was very broad beginning at about 80.degree. C. and 
ending at about 138.degree. C. This endotherm appeared to consist of two 
domains which peak at about 100.degree. C. and about 115.degree. C., 
respectively. The material in the higher temperature domain can be 
isolated by washing the the material with water in a pressurized vessel at 
a temperature above 100.degree. C., e.g. from about 105.degree. C. to 
about 110.degree. C. 
EXAMPLE 2 
High amylose starch (HI-SET C, National Starch and Chemical Co.) was first 
solubilized at 8.0% dry solids by weight by heating a slurry thereof in 
water in a pressure vessel to about 162.degree. C. The resulting solution 
was cooled to room temperature (about 25.degree. C.) and allowed to stir 
for 20 hours during which time a thick mass of crystals precipitated. Acid 
(HCl in an amount of 0.44 meq/gm of slurry) was added and hydrolysis of 
the crystals in the slurry was carried out at 69.degree. C. for four hours 
after which the solution was neutralized to pH 4.3 with 1.5N sodium 
hydroxide. The insoluble product was isolated by microfiltration of the 
slurry while the slurry was held at 94.degree. to 95.8.degree. C. The DSC 
endotherm of the resulting product appeared to consist of of a single 
domain which peaked at about 120.degree. C.