DP profile	M180	M150	M100	M050	M040

DP > 8	46.6 ± 4%	54.7 ± 4%	67.8 ± 4%	90.6 ± 4%	88.5 ± 4%
DP 8	3.9 ± 2%	4.8 ± 1.5%	4.5 ± 1.5%	1.5 ± 1%	2.0 ± 1%
DP 7	9.5 ± 2%	9.1 ± 1.5%	7.0 ± 1.5%	1.5 ± 1%	2.4 ± 1%
DP 6	11.4 ± 2%	8.4 ± 1.5%	6.1 ± 1.5%	1.4 ± 1%	1.8 ± 1%
DP 5	5.9 ± 2%	4.7 ± 1.5%	3.3 ± 1.5%	1.3 ± 1%	1.3 ± 1%
DP 4	6.4 ± 2%	5.5 ± 1.5%	3.7 ± 1.5%	1.1 ± 1%	1.4 ± 1%
DP 3	8.3 ± 2%	6.7 ± 1.5%	4.2 ± 1.5%	1.0 ± 1%	1.4 ± 1%
DP 2	6.2 ± 2%	4.8 ± 1%	2.5 ± 1%	0.8* ± 1%	0.9* ± 1%
DP 1	1.8 ± 1.5%	1.3 ± 1%	0.7* ± 1%	0.8* ± 1%	0.3* ± 1%

*MINIMUM VALUE = 0%

Each of these maltodextrins has at least 45% DP 10 or greater malto-oligosaccharide. Other suitable malto-oligosaccharide starting materials can include other malto-oligosaccharides, such as MALTRIN® M440, MALTRIN® M4510, MALTRIN® M580, MALTRIN® M550, and MALTRIN® M700, as well as corn syrup solids, such as MALTRIN® M200, MALTRIN® M250, and MALTRIN® M360.

In some embodiments of the invention, the starting material can include a limit dextrin. Limit dextrins are discussed in more detail in U.S. Pat. No. 6,670,155, assigned to Grain Processing Corporation and incorporated by reference in its entirety. Alternatively, or in addition thereto, the starting material may include another dextrin that comprises a starch that has been partially hydrolyzed by an alpha amylase enzyme but not to the theoretical or actual limit. Such dextrins are referred to herein as “prelimit dextrins.”

In accordance with some embodiments of the invention, at least a portion of the starting material is hydrogenated. Suitable teachings regarding the production of hydrogenated starch hydrolyzates, specifically malto-oligosaccharides, can be found in U.S. Pat. Nos. 7,728,125; 7,595,393; 7,405,293; 6,919,446; and 6,613,898, each entitled “Reduced Malto-Oligosaccharides” and assigned to Grain Processing Corporation, and incorporated by reference in their entireties. Generally, when a starting malto-oligosaccharide mixture is catalytically hydrogenated, the reduced malto-oligosaccharide mixture thus formed may have a DP profile that is not substantially altered as compared with the DP profile of the starting malto-oligosaccharide mixture. Other hydrogenated starch hydrolyzates may be employed.

The reaction mixture may include mixtures of the foregoing materials, all of which are contemplated as starch hydrolyzates suitable for use as starting materials,

The starch hydrolyzate as described hereinabove is dextrinized in the presence of a lower molecular weight saccharide, i.e., a saccharide having a degree of polymerization ranging from 1 to 4. The saccharide is denoted as separate ingredient from the starch hydrolyzate, even though starch hydrolyzates themselves typically include some amounts of DP 1-4 materials. Preferably, the saccharide is dextrose, optionally in combination with one or more other saccharides, such as maltose, maltotriose or maltotetraose. The dextrose may be in the form of a monohydrate.

If a mixture of saccharides is employed, the average DP of the mixture should be in the range of 1 to 4, preferably 1 to 3, and even more preferably 1 to 2. Mixtures of saccharides that can be employed include MALTRIN® M250 and MALTRIN® M360, Alternatively, the derivatizing saccharide may be maltose, maltotriose or maltotetraose in the presence or absence of dextrose. However, dextrose is the preferred saccharide. Most preferably, the dextrose is present as 100% of the weight of the saccharides having a DP ranging from 1 to 4, but dextrose may be present in any relative amount, such as 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20% or 10% by weight of saccharide having a DP from 1 to 4. Preferably, if a mixture of saccharides having a DP of 1 to 4 is employed, the saccharid.e includes dextrose or maltose in an amount of at least 50% by weight of the total saccharides having a DP of four or less.

Typically, an organic acid catalyst is also combined with the above noted ingredients. In one form, the organic acid catalyst is citric acid. Other acids may also be used as a catalyst, such as acetic acid, adipic acid, fumaric acid, gluconic acid, lactic acid, malic acid, phosphoric acid, and tartaric acid, or other food-grade acids.

The ingredients may be provided in varying amounts. For example, in one form, about 60 to about 80 wt. % dextrose or other saccharide may be combined with about 20 to about 40 wt. % maltodextrin or other hydrolyzate and a catalytic amount of citric acid, such as about 1 wt. %. In another form, about 70 wt. % dextrose is combined with about 30 wt. % maltodextrin and a catalytic amount of citric acid. In yet another form, about 75 wt. % dextrose is combined with about 25 wt % maltodextrin and a catalytic amount of citric acid. When describing the percentages of the starch hydrolyzate and the saccharide, these percentages refer to percentages on a dry solids basis. In other embodiments, the percentages of saccharide to hydrolyzate may be 10%/90%; 20%/80%; 30%/70%; 40%/60%; 50%50%; 60%/40%; 70%/30%; 80%/20%; or 90%/10%, or any desired range of ratios among these percentage ratios (e.g., 80%-90% saccharide and 10-20% hydrolyzate). For example, the maltodextrin may be present in an amount of 25%-75% based on the total weight of maltodextrin and dextrose.

Other ingredients (besides water) may be absent, or may be present in trace amounts, or alternatively in some embodiments other ingredients are added. For example, polyols need not be added and in many embodiments are not added. it is hypothesized that water or dextrose acts as a replacement for the external plasticizers.

As supplied, the starch hydrolyzate and saccharide ingredients may have 5-15% moisture content, and in some cases 5-10% moisture content. The ingredients used in this method may contain their natural equilibrium moisture so that it is not necessary to dry the ingredients prior to use, Alternatively, the ingredients may be partially dried to remove some of the moisture content. It is hypothesized that the moisture content of the ingredients serves two purposes, including reducing the melting point of the mixture (thereby functioning as a plasticizer) and reducing the viscosity of the melt, thus allowing any trapped air to easily escape. As a result, the bubbling problem which is predominant in dry state reactions is ameliorated.

The reaction can take place in any reaction vessel or apparatus suitable for derivatizing the starch hydrolyzate with the saccharide. In one form, glucose monohydrate, maltodextrins and catalytic amount of citric acid are placed in a conventional pyrodextrin reactor, as illustrated at reference number 10 inFIG. 1. The reaction may take place in a single pot reactor or may be moved between reaction vessels. The reaction may take place as a batch-type reaction or a continuous process.

After blending the ingredients, heat is applied at a temperature range of about 120-170° C. to allow the ingredients to “wet.” More preferably, a temperature range of about 140-160° C. is used. After allowing the ingredients to “wet” for few minutes, moderate and controlled vacuum is applied to the mixture, as illustrated at reference number 12. For example, a vacuum of about 10 to about 25 inches of mercury, more preferably about 10-20 inches of mercury and even more preferably 15 to 18 inches of mercury is applied into the system. It is hypothesized that this controlled vacuum helps remove air pockets within the ingredient mixture without greatly affecting the moisture content. It is believed that the removal of air further helps to prevent bubbling when the mixture eventually melts. By moderating the amount of vacuum and the temperature range, water may be removed slowly and may permit the moisture to act as plasticizer in place of sorbitol. Additionally, the vacuum drives the reaction chemistry through the removal of water from the system. The reaction may be completed within 2-4 hours.

Optionally, the resulting product may then be further processed to adjust the pH, as illustrated at reference number 14. The product may then also be purified, as illustrated at reference number 16, using one or more conventional purification techniques, including, but not limited to, carbon filtration, ion exchange, or chromatographic methods. Finally, the purified material may be spray dried, as illustrated at reference number 18, to achieve a final purified and dried product, as illustrated at reference number 20.

The process may be operated to provide a product having any suitable digestibility. A digestibility of from 10-20% is preferred in many embodiments, although other digestibility values are contemplated. Those skilled in the an will appreciate that various process parameters may he adjusted to affect the digestibility of the resultant product. Digestibility may be determined via a procedure adapted from Muir and O'Dea, “Measurement of resistant starch: factors affecting the amount of starch escaping digestion in vitro,”Am. J Clinical Nutrition56:123-27 (1992), incorporated by reference in its entirety. Generally, this procedure includes the following steps and incorporates the reagents specified below:

- 1. Weigh 0.1 g of sample carbohydrate (dsb) into 50 mL centrifuge tubes.
- 2. Add 2 mL water to each tube & vortex gently
- 3. Cook sample in a boiling water bath for 15 minutes and cool.
- 4. Add 1 mL pepsin/HCl solution & vortex gently.
- 5. Incubate for 30 minutes at 37° C.
- 6. Neutralize with 0.5 mL NaOH.
  perform steps 7a-10a on zero time sample.
- 7a. Add 5 mL 0.2M sodium acetate buffer & vortex
- 8a. Centrifuge at 3620 rpm for 10 minutes.
- 9a. Decant supernatant into a 50 mL centrifuge tube.
- 10a. Bring up to 10 mL volume with 0.2M sodium acetate buffer & vortex.
- 11a. Measure glucose.
  proceed with steps 7-13 on other time interval samples.
- 7. Add 5 mL 0.2M sodium acetate buffer and 1 mL of enzyme solution & vortex.
- 8. Incubate for specified time at 37° C. in a shaking water bath.
- 9. At specified time interval, quench sample at 100° C. for 10 minutes.
- 10. Centrifuge at 3620 rpm for 10 minutes.
- 11. Decant supernatant into a 50 mL centrifuge tube.
- 12. Bring up to 25 mL volume with 0.2M sodium acetate buffer & vortex.
- 13. Measure glucose
- 14. Digestibility is determined as the amount of glucose measured as a percentage of the original starch, each measured on a dry starch basis.

Reagents

Pepsin/HCl solution—Add 0.5 g of pepsin (1:10,000, Sigma P-7000) to 400 mL deionized water. Adjust to pH 2.0 with HCl. Add to 500 mL volumetric flask and bring up to volume with water. Store in refrigerator.

Sodium acetate buffer 0.2M—Add 16.408 g of anhydrous sodium acetate to 500 mL deionized water. Adjust to pH 5.0 with glacial acetic acid. Add to 1 liter volumetric flask and bring up to volume with water,

Enzyme solution—Place 0.24 g amyloglucosidase (Sigma A-7255) and 1.0 g α-amylase (Sigma A-6880) in a 100 mL volumetric flask Bring up to volume with 0.2M sodium acetate buffer, pH 5.0. Final solution will be 28 U/mL amyloglucosidase and 10 mg/mL α-amylase.

Bond methylation analysis may be performed in accordance with the procedures outlined in flakomori, S. I.,J. Blochem55:205-08 (1964), as modified by Kim et al.,Carbohydrate Research341:1061-64 (2006). Generally, in the methylation analysis, the material subject to analysis is exhaustively methylated using methyl iodide. This converts the free hydroxyl group to methyl ether. The methylated product is then exhaustively hydrolyzed with acid catalysis, thus creating a hydroxyl group at places where a glycosidic bond once existed. The product is then analyzed and the positions of the hydroxyl groups then determined. This represents where linkage points existed in the original products. The data is reported as t-glc, 2-glc, 3-glc, 4-glc, 6-glc, 3,4-glc, 4,6-glc, 2,6-glc+3,6-glc, 2,4-glc, 3,4,6-glc, 2,3,6-glc, where “t-gic” indicates a monomer resulting from a terminal glucose group, “2-glc” indicates a monomer resulting from a linkage at the 2-carbon position on the glucose ring, and so on. Plural denominations signify multiple branching points on the glucose ring; for instance, “3,4-glc” indicates a monomer formed where a branch point had existed at the 3- and 4-positions. The reducing end is subjected to another chemical step to render the reducing end similar to a similarly substituted interior unit (thus, for instance, a 1-4 linked oligomer resolves to t-glc and 4-glc). Other possible linked structures (2,3-glc or 2,3,4,6-glc) are believed to be formed in very small amounts. The methylation data does not differentiate between alpha and beta bonds, so methylation does not exactly correspond with digestibility as indicated above, but generally the larger number of 1-4 bonds and 1-6 bonds signifies greater digestibility.

A comparison of various resistant dextrins is shown below in Table 1. More specifically, Example 1 is the material resulting from the above described processing techniques. The extruded sample was produced from a prior art extrusion technique, while the polydextrose sample was produced by the large scale technique as discussed in the background. The FIBERSOL sample and NUTRIOSE samples are samples of commercially available products, also discussed in the background.

TABLE 1

Comparison of resistant dextrins.

				Poly-
Example 1	Extruded	FIBERSOL	NUTRIOSE	dextrose

%	10-20	30-40	4	15	5
Digesti-
bility
% glucose	5-8	5	0.4		0-4
DE	14-18	10-13	8-12	2-10	0-8
Mw	3200-3800	3500-5000	3200	800-6000	1300
1-4/1-6	36/27	60/20	48/25	56/38	predom.
linkages					1-6

no significant differences in ash, protein, fat, SO₂content or pH

In subsequent examples, glucose was reacted with maltodextrin using citric acid as a catalyst. In the process, a mixture of the ingredients was fed into the reactor without pre-drying. Various exemplary mixtures were prepared as found in Tables 2-4, and further processed as described below.

TABLE 2

Composition of Example 2

	Ingredient	% of total feedstock

	Dextrose monohydrate	64.35
	Maltodextrin (10 DE)	34.65
	Citric acid anhydrous	1.0

TABLE 3

Composition of Example 3 (1885-77-02A)

	Ingredient	% of total feedstock

	Dextrose monohydrate	74.25
	Maltodextrin (10 DE)	24.75
	Citric acid anhydrous	1.0

TABLE 4

Composition of Example 4

	Ingredient	% of total feedstock

	Dextrose monohydrate	69.3
	Maltodextrin (10 DE)	29.7
	Citric acid anhydrous	1.0

The starting ingredients had moisture content of about 10%, The reactor was heated to 180 to 190° C. under mixing without vacuum to allow moisture and trapped air bubbles to escape. Then under vacuum of about 10 to 12 inches of mercury, the mixture was allowed to react at between 140-160° C. for 2 to 4 hours, Under those conditions, glucose and other low molecular weight saccharides and the maltodextrin polymerized to higher MW polymer with mixture of glucosidic bonds. The moisture content at the completion of the reaction was about 2%.

In subsequent examples, following the processing steps shown inFIG. 1 and as described above, the following blends were prepared. The blends were not pre-dried. During reaction, vacuum was held at 15-18 in mercury and not allowed to exceed 20 in mercury. The reacted material was dropped or transferred to a cooling belt and, after cooling, ground to desired particle size. The resulting compositions are illustrated below in Table 5.

TABLE 5

Comparison of Examples 5-7

Item and
Target	Example 5	Example 6	Example 7

Formula	Dextrose monohydrate	Dextrose	Dextrose
	(74.25%)	monohydrate	monohydrate
	Maltodextrin (24.75%)	(69.3%)	(74.25%)
	Citric acid (1%)	Maltodextrin	Maltodextrin
		(29.7%)	(24.75%)
		Citric acid (1%)	Citric acid
			(1%)
Reaction	3 hour 50 minutes	2 hours 25 minutes	3 hour
Time			45 minutes
Reaction	160° C.	160° C.	140° C.
Temperature
Glucose	8.47	9.01	17.40
Residues
PH: 2-3	2.89	2.84	2.92
Moisture	0.95	0.9	0.8
1-2.5

Bond methylation data was determined according to the procedure outlined above for Examples 5 and 6, yielding the following,

TABLE 6

Bond Methylation

	%	%
linked-glc	Example 5	Example 6

t-glc	27.5	28.6
2-glc	6.1	6.4
3-glc	7.0	7.2
4-glc	20.0	18.0
6-glc	17.9	18.6
3,4-glc	0.7	0.8
4,6-glc	10.5	9.6
2,6-glc + 3,6-	6.3	6.6
glc
2,4-glc	0.9	1.1
3,4,6-glc	1.5	1.6
2,4,6-glc	1.1	1.1
2,3,6-glc	0.4	0.5
	99.90	100.10

From the above, it was determined that the percentages of 1-4 and 1-6 bonds in the product of Example 5 were 35.8 and 38.9, respectively. In the product of Example 6, the percentages of 1-4 and 1-6 bonds were 33.5 and 39.6 respectively.

The methods described above may provide a number of advantages over previous methods for manufacturing resistant dextrins. For example, the methods described herein may eliminate the step of making a dextrin from a starch. As noted previously, those prior art processes use environment-unfriendly hazardous strong acids like hydrochloric acid to make dextrins through a dry-roasting dextrinization process and requires pre-drying of the feedstock to 2-3% moisture content and high temperature. In many of the present methods, mineral acids are not used.

Further, the presently proposed methods may eliminate the step of hydrolyzing and removing the digestible part of the dextrin made from a starch. As noted above, prior art methods generally produced materials having a significant portion which was digestible. To increase the percentage of the non-digestible dextrins in the final product, an amylase or glucoamylase or other enzyme combinations were often used to hydrolyze the digestible part to glucose or maltose so that the non-digestible part could be separated out from the digestible part by organic solvent or alcohol precipitation, membrane separation and other separation technology based on molecular size difference. Similarly, the proposed methods may reduce waste and increase yield of the finished non-digestible products because there are digestible parts that need to be removed.

The starting materials may not need to be pre-dried, as is necessary in the prior art. Additionally, the methods proposed herein may avoid the use of polyols like sorbitol. As noted above, the moisture content of the ingredients along with the processing conditions, such as the temperature ranges and vacuum ranges, permit the materials to react without excessive foaming and without the need to use polyols.

It is thus seen that a method for preparation of resistant dextrins is provided. It is believed that the dextrins thus formed may contribute to a cholesterol-lowering effect when consumed by humans or other mammals. In some embodiments, the invention contemplates providing a resistant dextrin to a mammal for purposes of reducing the blood cholesterol value.

Uses of singular terms such as “a,” “an,” are intended to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms. Any description of certain embodiments as “preferred” embodiments, and other recitation of embodiments, features, or ranges as being preferred, or suggestion that such are preferred, is not deemed to be limiting. The invention is deemed to encompass embodiments that are presently deemed to be less preferred and that may be described herein as such. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended to illuminate the invention and does not pose a limitation on the scope of the invention. Any statement herein as to the nature or benefits of the invention or of the preferred embodiments is not intended to be limiting. This invention includes all modifications and equivalents of the subject matter recited herein 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. The description herein of any reference or patent, even if identified as “prior,” is not intended to constitute a concession that such reference or patent is available as prior art against the present invention. No unclaimed language should be deemed to limit the invention in scope. Any statements or suggestions herein that certain features constitute a component of the claimed invention are not intended to be limiting unless reflected in the appended claims. Neither the marking of the patent number on any product nor the identification of the patent number in connection with any service should be deemed a representation that all embodiments described herein are incorporated into such product or service.