Chapter 4
Encapsulation
of
Orange O i l
Use of Oligosaccharides from α-Amylase Modified Starches of Maize, Rice, Cassava, and Potato 1
1
Downloaded by UNIV OF MONTANA on January 25, 2016 | http://pubs.acs.org Publication Date: May 31, 1988 | doi: 10.1021/bk-1988-0370.ch004
G. E . Inglett, P. Gelbman , and Gary A. Reineccius
Agricultural Research Service, U.S. Department of Agriculture, Northern Regional Research Center, 1815 North University Street, Peoria, IL 61604 Oligosaccharides were prepared by the action of alpha-amylase on ordinary corn, waxy corn, amylomaize VII corn, rice, wheat, cassava and potato starches; their compositions, were measured by HPLC on a HPX-42A column. The oligosaccharides were used to encapsulate single-fold orange oil at an optimum infeed concentration and to achieve maximum flavor retention during spray drying. A l l the oligosaccharides provided ideal viscosity for the infeed mixtures. The spray-dried samples were analyzed for total oil, surface oil, moisture content, shelf l i f e and for emulsion stability by observing optical density changes with time on a centrifuged aqueous mixture. Retention of orange o i l during spray drying was best with wheat and amylomaize VII oligosaccharides, whereas waxy corn and cassava oligomers appear to be best for shelf l i f e . Numerous materials are commercially available f o r use as flavor encapsulating agents v i a spray drying (4). However, each of these materials has one or more l i m i t a t i o n s . Chemically-modified starches ( i . e . , having emulsifying properties) have been shown to y i e l d excellent retention of v o l a t i l e s during drying (4), but provide poor protection to oxidation (7). The p a r t i a l l y hydrolyzed starches (e.g., maltodextrins and glucose syrup s o l i d s ) provide excellent protection against oxidation of the encapsulated flavor but give no emulsification and y i e l d poor retention of v o l a t i l e s (_1). Gum arabic provides excellent emulsif i c a t i o n and good retention of v o l a t i l e s but provides limited protection against oxidation (7). In recent years, cost and a v a i l a b i l i t y have also been deterrents to the use of gum arabic. While select blends of commercially available c a r r i e r s may provide acceptable retention and s h e l f - l i f e , the search continues to develop a superior flavor c a r r i e r at an acceptable cost. To t h i s end, we have enzymatically hydrolyzed various starches and evaluated t h e i r p o t e n t i a l for use as f l a v o r encapsulating materials. 1
Current address: Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108 ^ c h a p t e f n Q ts u b j e c t t Qυ
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Published 1988 American Chemical Society
In Flavor Encapsulation; Risch, Sara J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
30
FLAVOR
ENCAPSULATION
Materials and Methods
Downloaded by UNIV OF MONTANA on January 25, 2016 | http://pubs.acs.org Publication Date: May 31, 1988 | doi: 10.1021/bk-1988-0370.ch004
Preparation of oligosaccharides. Waxy corn (Frodex 25, American-Maize Products Co., Hammond, IN), ordinary corn (Maltrin M-250, Grain Processing Corp., Muscatine, IA) and potato (Avebe America Inc., Hopelawn, NJ) hydrolysates were obtained commercially. Wheat, cassava, r i c e , and amylomaize VII starches were enzymatically hydrolyzed using a thermally stable alpha-amylase from B a c i l l u s licheniformis (E.C.3.2.1.1; 1,4-alpha-D-glucan glucanohydrolase; Taka-Therm L-340 from Biotech Products D i v i s i o n of Miles Laboratories, Inc., Elkhart, IN). While the procedure for hydrolysis was detailed previously (3), a b r i e f outline follows. Glucose syrup s o l i d s from wheat, r i c e , and cassava starches. A starch suspension was prepared by mixing 250 g of the starch with 580 mL of d i s t i l l e d water (30% w/w). The water contained 87 ppm of calcium (0.32 g per L CaCl2.2H 0). The pH of the s l u r r y was adjusted to 6.0 with 1.0 Ν NaOH. Thermally stable alpha-amylase from B a c i l l u s licheniformis was added to the s t i r r e d suspension (0.20 mL, 68,000 Modified Wohlgemuth Units (MWU), per 250 g of starch) at 50°C; the suspension was heated to 95°C i n a 2-L round-bottomed flask with continuous s t i r r i n g i n a bath containing ethylene g l y c o l . The conversion was allowed to proceed for 1 hr or u n t i l the desired degree of hydrolysis was obtained. After the desired conversion time, 0.1% of Darco G-60 and 2% of J.M. Hyflo F i l t e r Cel (based on solution weight) were mixed into the solution with continuous s t i r r i n g . The pH was adjusted to 3.5-4.0 with 0.2 Ν s u l f u r i c acid and the mixture was heated at 95°C f o r 10 min to inactivate the remaining enzyme. The pH was raised to 6.5 with 1 Ν NaOH, and the mixture was f i l t e r e d hot through a bed of f i l t e r - a i d on Whatman No. 1 paper i n a Buchner funnel under vacuum. The r e s u l t i n g f i l t r a t e s were dried i n a Model GA-31 Pulvis Mini Spray Dryer (Yamato, Northbrook, I L ) . 2
Maltodextrin from high-amylose corn starch. A suspension of high-amylose corn starch (Amylomaize VII, a product of American Maize Products Co., Hammond, IN) was prepared by mixing 250 g (20% w/w) with 1000 mL of water containing 87 ppm of calcium (0.32 g per L CaCl2.2HoO). The starch was gelatinized i n a jet-cooker at 280-290°F (30-40 l b of steam pressure). The gelatinized starch s l u r r y was collected i n a Dewar f l a s k , and the pH was adjusted to 6.0 with 1.0 Ν NaOH. Alpha-amylase (Taka-Therm L-340, 0.2 mL per 250 g of starch at 90-95°C) was added to the s t i r r e d suspension, and then heated to 95°C i n a 3-L round-bottomed f l a s k with continuous s t i r r i n g i n a bath containing ethylene g l y c o l . The conversion was allowed to proceed for 1 hr or u n t i l the desired degree of hydrolysis was obtained. The malto-oligosaccharides were processed as described e a r l i e r (3). HPLC analysis of starch hydrolysates. The oligosaccharide compositions of the various starch hydrolysates used i n t h i s study were determined by high performance l i q u i d chromatography (HPLC). An automated l i q u i d chromatographic system used i n t h i s study
In Flavor Encapsulation; Risch, Sara J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
Downloaded by UNIV OF MONTANA on January 25, 2016 | http://pubs.acs.org Publication Date: May 31, 1988 | doi: 10.1021/bk-1988-0370.ch004
4.
INGLETT E T AL.
Encapsulation of Orange Oil: Use of Oligosaccharides
31
consisted of a Spectra Physics (San Jose, CA) Model 8700XR pump c o n t r o l l e r and an organizer (SP8750S) for the solvent delivery system; a Model 410 d i f f e r e n t i a l refractometer (Waters Associates, Milford, MA); and a Spectra Physics computing integrator (SP4270). The column was an Aminex HPX-42A (300 χ 7.8 mm) from Bio-Rad Laboratories (Richmond, CA), held at 85°C i n a column heater (Bio-Rad Laboratories, No. 125-0425). The method and quantitation has been detailed by Inglett (3). Oligosaccharide compositions of the various starch hydrolysates are shown i n Table I. The reducing sugar contents (expressed as dextrose equivalents, DE) were estimated from the hydrolysate compositions by dividing the content of each oligomer by i t s DP and adding the eight numbers. The following are the estimated DE values: ordinary corn, 25; waxy corn, 24; amylomaize, 17; wheat, 26; r i c e , 27; potato, 18; and cassava, 24. Maltodextrins are defined by the FDA as having DE less than 20; syrup s o l i d s are defined as dried glucose syrups i n which the DE i s 20 or higher. Spray drying. Single f o l d Valencia peel o i l without antioxidant was provided by Fries and F r i e s (Cincinnati, OH). A quantity of orange o i l corresponding to 25% (by weight) of the c a r r i e r s o l i d s was added to a 50% s o l i d s aqueous solution of each enzyme-modified starch. The orange o i l emulsion was homogenized using a Greer Co. (Hudson, NH) laboratory high shear mixer f o r 3 min immediately p r i o r to spray drying. A Niro U t i l i t y Dryer (Columbia, MD) equipped with a 12 cm diameter r a d i a l vane c e n t r i f u g a l atomizer (24,000 rpm) was used for spray drying. Drying conditions were standardized at an i n l e t a i r temperature of 200 + 5°C and an exit a i r temperature of 100 + 3°C using cocurrent flow. Under these conditions, the dryer was evaporating about 12 Kg water per hour. Analysis of Spray Dried Samples. Moisture content was determined in duplicate v i a toluene d i s t i l l a t i o n and t o t a l v o l a t i l e o i l by Clevenger (JO. Surface o i l was measured by Soxhlet extraction (2). S h e l f - l i f e was determined by gas chromatography (6); the end of s h e l f - l i f e was the time taken (at 37°C storage) to reach a limonene epoxide concentration of 2 mg/g o i l . Results and Discussion A l l hydrolyzed starches r e a d i l y went into solution at 50% s o l i d s . The v i s c o s i t i e s of a l l solutions were quite low (
Table I. Oligosaccharide Compositions Prepared from Starches by Thermal Stable Alpha-Amylase Actions*
Downloaded by UNIV OF MONTANA on January 25, 2016 | http://pubs.acs.org Publication Date: May 31, 1988 | doi: 10.1021/bk-1988-0370.ch004
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