Carbohydrate profiles

Fox, A. Black, G. Fox, K. Rostovtseva, S. Determination of carbohydrate profiles of Bacillus anthracis and Bacillus cereus including identification of (9-methyl methylpentoses using gas chromatography-mass spectrometry. J. Clin. Microbiol. 1993, 31, 887-894. 

Wunschel, D. K. Fox, K. Black, G. Fox, A. Discrimination among the Bacillus cereus group, in comparison to B. subtilis, by structural carbohydrate profiles and ribosomal RNA spacer region PCR System. Appl. Microbiol. 1994,17, 625-635. 

Gilbart, J. Fox, A. Morgan, S. L. Carbohydrate profiling of bacteria by gas chromatography-mass spectrometry Chemical derivatization and analytical pyrolysis. Eur. I. Clin. Microbiol. 1987, 6,715-723. 

Figure 3.12 Metabolic profiling by capillary electrophoresis, (a) Comparative carbohydrate profiles of M. truncatula tissue obtained using 4-aminobenzonitrile derivatization, capillary electrophoresis with a 150 mM borate buffer, pH = 9, and on-column UV detection at 214 nm. (b) Anion profile from M. truncatula using capillary electrophoresis and indirect UV detection. The separation buffer was 5 mM K2C1O4, 1% Waters OFM-Anion BT, pH 8.0.

Eor obtaining neutral fraction the column was eluted with water firstly. The acidic fractions were obtained by elution of linear NaCI gradient (0-1.4 M) in water. The carbohydrate elution profile was determined using the phenol-sulphiric acid method, finally two column volumes of a 2 M sodium chloride solution in water were eluted to obtain the most acidic polysaccharide fraction. The relevant fractions based on the carbohydrate profile were collected, dialysed and lyophilized. 

Table I. Typical Carbohydrate Profile (Carbohydrate analysis by HPLC, % by weight )...

Glucose syrups, also known as com syrups in the United States, are defined by the European Commission (EC) as a refined, concentrated aqueous solution of D(+)-glucose, maltose and other polymers of D-glucose obtained by the controlled partial hydrolysis of starch (Howling, 1984). Glucose syrups were fust manufactured industrially in the nineteenth century by acid hydrolysis of starch. Hydrochloric acid was normally used, because sulphuric acid caused haze in syrups due to insoluble sulphates. The source of starch can vary in the United States corn is widely used, whereas in other parts of the world wheat, potato and cassava starch are also employed. Acid hydrolysis of starch is still used today. The method is non-specific, but if conditions are tightly controlled, it is possible to make products with a reasonably consistent carbohydrate profile. 

Refractive index (RI) is a measure of the refraction of light rays as they pass obliquely from one solution to another of different density. Refractive index is commonly used to measure the solids level of sweeteners. The refractive index of a sweetener is a function of the carbohydrate profiles, ash level, solids level and temperature of the solution. 

Table 21.1 Typical carbohydrate profile of commercial maltodextrins15...

In an acid process the slurry, containing about 35-45% starch solids, is pumped into a pressure vessel called a converter and acidified to a pH of about 2.0 with dilute hydrochloric acid at 140-160°C and a pressure of 80 psi (5.4 atm). Although acid-catalyzed hydrolysis is a rather (but not completely) random process,19,20 carefully controlled hydrolysis produces syrups in the 25 to 45 DE range with very predictable carbohydrate profiles as shown in Table 21.2.21... 

As in the case of acid-catalyzed hydrolysis, the starch molecule is hydrolyzed to the desired starting DE in a converter, but further conversion is carried out with enzymes until the final DE or carbohydrate profile is reached. This is done by adding the appropriate enzymes to the acid-converted slurry and allowing them to react in a holding vessel called an enzyme tank. Several enzymes may be used to achieve the desired carbohydrate profile. 

At completion of the enzyme conversion, the tanks are emptied in succession and the liquor is processed through filtration and carbon bleaching, as previously described, and evaporated to the proper solids level. The advent of enzyme-converted syrups lessens the importance of traditional methods of measurement, such as determination of DE. It is possible to have two syrups with the same DE and completely different carbohydrate profiles and performance characteristics, as shown in Table 21.4.31... 

Physical properties of a syrup depend heavily on its carbohydrate profile. The carbohydrate profile, in turn, is determined by the type of conversion and the nature of the enzyme treatment (previously discussed). Table 21.2 gives typical DE and carbohydrate profiles of syrups in common production today. Because enzyme treatments can provide sweeteners with different carbohydrate profiles but the same DE value, it is usual to refer to a product using more than one descriptor, e.g. a 43 DE, high-maltose syrup. This issue becomes particularly important when addressing functional differences and applications of starch-derived sweeteners. 

In addition to DE values and carbohydrate profiles, syrups are usually identified by their solids level. The traditional means of expressing the solids of a glucose/syrup is the Baume number. Extensive work comparing the Baume number to refractive index... 

As in the case of freezing point depression, boiling point elevation depends on the carbohydrate profile. In general, the boiling point is increased as the level of conversion increases. Table 21.15 shows the relationship of boiling point to solids content for various sweeteners.76... 

Figure 12.12 Carbohydrate profiles of plain and flavoured yoghurts on the Aniinex HPX-87P eoluinn, 300 x 7.8 mm. Eluant H P. Flow rate 0.6 ml min. Temperature 85°C. Detection RI at 32x. (a) Plain yoghurt, diluted 1 1 20pl. (b) Strawberry yoghurt, diluted 1 2 20pl. (c) Bluebeny yoghurt, diluted 1 1 20 pi. Peaks 1, Sucrose (and maltose in (c)) 2, Lactose 3, Glucose 4, Galactose 5, Fructose.

Prodolliet J., Bruelhart M., Lador F., Martinez C. et al. (1995a) Determination of free and total carbohydrate profile in soluble coffee. J. Ass. Off. Anal. Chem. 78(3), 749-61. 

Size exclusion chromatography (for monomer content) Carbohydrate profile Deamidated species (%)... 

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