Chapter 2
Maltodextrins and Low-Dextrose-Equivalence Corn Syrup Solids Production and Technology for the Flavor Industry
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Melanie M . Kenyon and Robert J . Anderson Grain Processing Corporation, 1600 Oregon Street, Muscatine, IA 52761 Maltodextrins are nonsweet soluble carbohydrates that are used in flavor encapsulation and throughout the food industry. This paper presents information on how maltodextrins are produced, their chemical and phy sical properties, and the functional characteristics that make maltodextrins useful to the flavor industry.
Encapsulation and drying of flavors are dependent on the performance of encapsulating agents. These agents should: 1. 2. 3.
Protect the active ingredient from oxidation, caused by heat, l i g h t , humidity, and other substances over a long shelf l i f e . Prevent the evaporation of v o l a t i l e components. Provide the a b i l i t y to put the active ingredient into a freeflowing powder for ease of handling and incorporation into dry food systems (King, T. et a l . , 1976).
To provide these functions, the encapsulating agent should have the following properties (King et a l . , 1976): emulsion s t a b i l i z i n g c a p a b i l i t i e s ; film-forming a b i l i t y ; low hygroscopicity; low v i s c o s i t y ; and the a b i l i t y to release the active ingredient upon hydration as well as be of r e l a t i v e l y low cost and i n r e l i a b l e supply. Maltodextrins and low DE corn syrup solids can be an important part of the matrix system for the encapsulation and drying of flavors. D e f i n i t i o n of Maltodextrins and Corn Syrup Solids The FDA defines maltodextrin (C Hi2C>5) Η£θ (CAS. Reg. No. 9050-36-6) as nonsweet, n u t r i t i v e saccharide polymers that consist of D-glucose units linked primarily by alpha-1-4 bonds and that have dextrose equivalence (DE) less than 20. They are prepared as white powders or concentrated solutions by p a r t i a l hydrolysis of corn starch with safe and suitable acids and/or enzymes (48FR51911, Nov. 15, 1983). 6
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0097-6156/88/0370-0007$06.00/0 1988 American Chemical Society
In Flavor Encapsulation; Risch, S., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
FLAVOR
8
ENCAPSULATION
Maltodextrins are generally recognized as safe (GRAS) as a d i r e c t human food ingredient at levels consistent with current good manufac turing practices (21 CFR 184.1444). Corn syrup solids ( 0 Η χ 0 5 ) η 2 ° ( « S « 68131-37-3) are defined by the FDA as dried glucose syrups (21 CFR 168.121) i n which the reducing sugar content (DE) i s 20.0 or higher. Corn syrup solids are presently under GRAS review along with other sweeteners and table syrups. H
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C A S
R e
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Production of Maltodextrins and Corn Syrup Solids Maltodextrins and corn syrup solids are produced from starch, usually corn. The starch, which i s almost pure carbohydrate, i s cooked or pasted to open the granule and then hydrolyzed. Products can be made by hydrolyzing with acid or enzymes or with a combination of acid and enzymes. After the desired amount of hydrolysis has occurred, the reaction i s stopped, and the product i s f i l t e r e d to remove insoluble materials and then dried. Maltodextrins and corn syrup solids are most often defined by their dextrose equivalence (DE). DE i s a measure of the degree of hydrolysis of the starch molecule which compares the reducing power of the sugar groups as compared to the reducing power of an equal weight of glucose present. Other methods that are used to characterize maltodextrins and corn syrup solids include l i q u i d chromatography which can be used to quantify the r e l a t i v e amounts of shorter chain polymers found i n a p a r t i c u l a r DE product. Maltodextrins and corn syrup solids are made up of polymers of anhydroglucose units having varied chain lengths rather than one p a r t i c u l a r polymer size (Table I ) . Table I. Typical Carbohydrate P r o f i l e (Carbohydrate analysis by HPLC, % by weight ) Degree of Polymerization, DP 1 2 3 4 5 6 7 8 9 10 Above 10
Maltodextrins and Corn Syrup Solids 20 DE 5 DE 15 DE 10 DE 0.2 0.3 0.6 0.6 0.6 1.0 1.2 0.8 0.5 0.3 93.9
0.5 2.7 4.3 3.7 3.1 5.7 7.1 4.5 3.1 1.6 63.7
0.7 4.5 6.6 5.3 4.4 8.6 9.8 4.9 2.9 0.3 52.0
2.3 7.9 9.6 6.2 5.5 12.7 9.8 2.5 0.2 0.1 43.2
The average molecular weight decreases as the DE of a maltodextrin increases, but even at low DE's, i t i s much smaller than the o r i g i n a l starch: 5 DE - 3600; 10 DE - 1800; 15> DE - 1200; 20 DE - 900.
In Flavor Encapsulation; Risch, S., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
2.
KENYON & ANDERSON
Corn Syrup Solids
9
This r e l a t i v e molecular size difference between starch and the hydrolysis sugars gives maltodextrins and corn syrup solids their valuable functional properties for the flavor industry.
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Functional Properties Emulsion S t a b i l i z a t i o n . Emulsion droplet size and s t a b i l i t y are c r i t i c a l for the production of encapsulated flavor o i l s , Maltodextrins and corn syrup solids do not have "true" emulsifying c a p a b i l i t i e s ( l i p o p h y l l i c / h y d r o p h y l l i c properties). They are made up of glucose units, but the average chain length i s also too small to s t a b i l i z e normal levels of c i t r u s o i l s or other o i l carried flavors by v i s c o s i t y . For these reasons, maltodextrins are usually combined with other true emulsifying matrix materials such as gum arabic or spec i a l l y modified starches to achieve the necessary emulsion s t a b i l i t y . The amount of the emulsifying agent necessary w i l l vary depending on i t s a b i l i t y to emulsify, the l e v e l of o i l to be encapsulated, the production system used, and the desired s t a b i l i t y when the encapsulated o i l i s used. Film-Forming Properties. In the encapsulation of flavors, the quality of the end product i s affected by both how quickly the matrix material forms a film or selective membrane around the flavoring agent, and by the quality of the matrix f i l m and i t s a b i l i t y to protect the flavoring agent. Menting and Hoogstad (1967) studied the e f f e c t of increasing matrix concentrations on v o l a t i l e s retention using one maltodextrin. They reported an increase i n solids increased the rate at which a selective film formed to capture the v o l a t i l e s . Bangs and Reineccius (1981) studied the influence of maltodextrin DE on the retention of v o l a t i l e flavor compounds; they found that the average retention of combined v o l a t i l e components decreased with an increase i n the DE of the maltodextrin. Reineccius and Bangs (1985) also reported that an optimum feed solids content may vary depending on the composition of the solids and the c h a r a c t e r i s t i c s of the flavor components. Subramaniam (1984) reported an increase i n protection of encapsulated orange o i l during storage with an increase i n DE of the matrix s o l i d s . These references and others point to a need for further study to relate the properties of maltodextrins and corn syrup solids films to their a b i l i t i e s as flavor encapsulating agents. Hygroscopic!ty. Maltodextrins and low DE corn syrup solids are very nonhygroscopic. Therefore, flavors dried with these products are free-flowing powders. Hygroscopicity does increase with higher DE's. Figure 1 shows the physical changes i n several DE products that had equilibrated at various r e l a t i v e humidities. V i s c o s i t y . V i s c o s i t y and s o l u b i l i t y may be the two most important c h a r a c t e r i s t i c s of an encapsulation matrix ingredient. The increase in solids to the dryer at a constant s o l i d s / f l a v o r r a t i o can greatly increase the economic e f f i c i e n c y of an operation. Most processing systems have a maximum v i s c o s i t y at which they can operate. Proper atomization may also affect the flavor retention (Reineccius and Bangs 1985). The low v i s c o s i t y of maltodextrins and corn syrup solids i s shown i n Figure 2. The v i s c o s i t y of these products
In Flavor Encapsulation; Risch, S., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
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FLAVOR
STARCH
5 DE
10 DE
F i g u r e 1. Effect Characteristics.
of
20 DE
ENCAPSULATION
42 DE
Relative
H u m i d i t y on
5 DE 10 OE • 15 DE • 20 DE
Physical
* D
/
1000
.3-
100
10
0
À
10
20
30
40
50
ι
60
70
% Solids
Figure Solids
2. V i s c o s i t y of M a l t o d e x t r i n and Corn Solutions at Varied Percent Solids.
In Flavor Encapsulation; Risch, S., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
Syrup
2.
Corn Syrup Solids
KENYON & ANDERSON
11
decreases with increasing DE's. Maltodextrins and corn syrup solids also exhibit Newtonian v i s c o s i t y , decreasing i n v i s c o s i t y as they are heated. Maximum solids levels for encapsulation may also be reached at the s o l u b i l i t y l i m i t s of the matrix ingredients. Above these l i m i t s , the l e v e l of flavor compound may be out of r a t i o with the active matrix polymers, so the retention of flavor decreases (Reineccius and Bangs 1 9 8 5 ) . Insoluble materials may also a f f e c t the quality of encapsulating f i l m by i n t e r f e r i n g with the continuous f i l m matrix. Maltodextrins and corn syrup solids w i l l demonstrate good s o l u b i l i t y i n the following solids range: 5 DE - 3 0 - 4 5 % ;
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10
DE
- 45-55%;
1 5 DE
- 50-65%;
2 0 DE
60-75%.
Flavor Release. Encapsulated flavors find uses throughout the food industry. One major example would be beverage dry mixes. Maltodextrins and corn syrup solids have excellent cold water s o l u b i l i t y , so their use i n encapsulated flavors w i l l provide a rapid release of flavors used i n beverage applications. Maltodextrins and low DE corn syrup solids also have very l i t t l e flavor or sweetness of their own, form clear solutions, and v i r t u a l l y disappear once i n an application. Low Cost-Reliable Supply. Maltodextrins and corn syrup solids carry a much lower cost than almost a l l other encapsulating matrix ingre dients. They are produced both i n the U.S. and i n foreign countries by several suppliers, so they are readily available. When used alone or as one of a combination of encapsulation matrix ingredients, maltodextrins and corn syrup solids are an e f f e c t i v e part of the encapsulating system.
Literature Cited 1.
King, W.; Trubiano, P.; Perry, P . , Food Prod. Devel., 1 9 7 6 , 1 0 ,
2.
Menting, L . C., and Hoogstad, B . , J. Food Science, 1 9 6 7 , 3 2 ,
3.
Bangs, W., and Reineccius, G. Α . , J. Food Science, 1 9 8 1 , 4 7 ,
4.
Reineccius, G. Α . , and Bangs, W., Perf. Flavor, 1 9 8 5 ,
5.
Subramaniam, Α . , Thesis, University of Minnesota, Minnesota,
54,
56-57.
87-90. 254-259.
9,
1984.
RECEIVED December 29, 1987
In Flavor Encapsulation; Risch, S., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
27-29.
