New Technology for Invert Sugar and High Fructose Syrups from Sugarcane
Total Page:16
File Type:pdf, Size:1020Kb
Indian Journal of Chemical Technology Vol. 8, January 200 I, pp. 28-32 New technology for invert sugar and high fructose syrups from sugarcane J K Gehl awat Raha Gchlawat Sugar Academy, 248, R K Vihar, I P Extension, Delhi 110092, In dia Receil·ed 28 Jun e 1998; accepred 13 No1'e111ber 2000 The in vert sugar is an cquimolar mixture of glucose and fructose. It may be obtained on hydrolys is of sucrose under milder conditi ons using st rong cationi c res in s. The fru ctose contelll may be incre::tsed to about 60 per cent level by a partial removal of glu cose from invert sugar using th e tec hnique of column chromatography. The re sultant product is called hi gh fructose syrups (HFS) whi ch is traditi onal ly produced from starch. HFS may be produced from sucrose wi th econom ic adva ntage by thi s novel process. The production of invert sugar and hi gh fructose sy rups from suc rose (cane juice) is cost effec ti ve. It has been co mmercialized in In dia . This paper discusses the sa li ent features of thi s novel technology, which results in an effective 25 per cent increase in the sweetener output from the same quantity of sugarcane as molasses as a waste product is avoided. In vert Sugar of high purity (+98 DE) starch hydrolysates usi ng In vert sugar finds applications for biscuits, immobilized glucose isomerase as th e catalyst. The confectionery, beverages, bakery , several other food equ ilibrium mixture thu s obtained contain s about 42 and pharmaceutical formu lations. Traditionally, invert per cent fructose and 58 per cent glucose. sugar is produced from sucrose using minerals acids Commercially acceptable syrups must possess like H2S0 4 and HCI. This conventional method minimum 55 per cent fr uctose content. This is suffers from low conversion efficiency (65-70 per ach ieved by enrichment of fructose content in th e cent), hi gh ash content and undesirable products (7-8 mixture through column chromatography. Geh lawat per cent). Moreover, the invert syrup thu s obtained is has been a strong supporter of production of HFS on dark in colour. In view of these drawbacks of the large scale in Indi a to supplement the supply of cane 8 10 traditional process, attempts have been made to sugar • • The production of hi gh fructose syrups from develop alternate methods to produce invert su gar sucrose through its cationic inversion has been 11 und er relatively milder process conditions. Enzymatic suggested • hydrolysis of sucrose with in ve rtase has been Cane juice is the principal source of sucrose. The 1 3 recommended in the literature • • Recentl y, the use of raw cane juice may be clarified by membrane an immobilized invertase as a catalyst in a fixed-bed techniques like ultrafiltration to el iminate organic reactor is claimed to produce invert sugar sy rups of impurities and by electrodialysis to remove inorgani c . I . ? 4 12 16 I11 g 1 punty-· . salts • • The sucrose soluti on (c larifi ed cane juice) thu s obtained may be inverted in a fix ed bed reactor Inversion of sucrose may be carried out using of strong cation res ins as di sc ussed by Seema and ca tioni c res in s. Strong cationic resin s behave as 17 18 Geblawat and Sinha and Gehlawat . Nea rly equ al catalysts in liquid media. They possess catalytic amou nts of glucose and fr uctose are formed with properties comparable to strong acids. Thus, by cation resins in H+ form. Interestingly, theCa++ form choosi ng a cation resin of· proper acidity and porosity, of the same res in is found to separate glucose from any degree of sucrose inversion could be achieved 9 fructose in column chromatography' . without the introd ucti on of any electrolyte into the 5 6 syrup · . The inversion of sucrose usin g strong cation Inversion of sucrose present in refined cane juice is resins is a cheaper process for invert sugars and hi gh the most economical meth od of obtaining eq uimolar 7 fru ctose syrups . mixtures of glucose and fru ctose which on enri chment through the column chromatographic technique High Fructose Syrups produces the cheapest and superior grades of hi gh During the past three decades, high fructose syru ps fructose syrups. Thus, in India, HFS from cane juice (HFS ) have emerged as cheaper alternati ve may compete favou:·ab ly with the syrups obtained 17 20 sweeteners. They are manufactured by isomerization from corn in countries like USA ' . Fig. 1 shows two GEHLAWAT: INVERT SUGAR AND HIGH FRUCTOSE SYRUPS FROM SUGARCANE 29 c,z Hn o,, H~ /Invertase .+ + Sucrose INVERSION Glucose Fructose t Invert SugarT J Adsorp-tion . , Chromatography~ c::Y + (/) .......0 c::Y u (/) :J c 0 L.. 0 u c lL ·-....... ~ 0 1J u <-9:;: c::Y a .r:. L.. c::Y u .~ lL '-- a L.. :J L.. c Q_ lL w Enzymatic ~ High Fructose Isomerization Syrups Jl l.__. For- Sates Glucose ~ t (C6 H1005) n H .fd•[3Amytases rtC6H1206 + Starch HYDROLYSIS Glucose Fig. !-Chemistry and method of productionof fructose and high fructose syrups alternate schemes for the production of fr uctose and a reasonably fast reaction and complete inversion high fructose syrups. occurs within about 30 min under optimum This paper describes recent developments for the conditions. This technology has been commercialized 22 production of invert sugar and high fructose syrups. with excellent results . The details of the process 20 Table 1 gives data on relati ve sweetness of common have been reported elsewhere . Invert sugar is sugars and Table 2 provides typical composition of obtained on hydrolysis of sucrose. The final syrup commercial grades of high fructose syrups. contains about 75-80 per cent dry solids (mixture of glucose and fructose). It has a relative sweetness of New Technology for Invert Sugar 120 as compared to sucrose as 100 (Table I). Fig. 3 India has taken a lead in developing new processes for shows the process flowsheet. Scheme A is for the invert sugar. The National Research and Development production of syrtip from refined cane juice during the Corporation (NRDC) is marketing the enzyme season. Scheme - B is with crystal sugar as the raw process developed by Bhabha Atomic Research material that may be used during the off season. Centre (BARC). A few plants have been set up based 1 on thi s technolog/ • lndian I~stitut e of Technology, Cheaper Syrups from Cane juice Kanpur, has developed a novel process based on resin Traditionally high fructose syrups are produced 7 20 technolog/·' · . Fi g. 2 shows the kinetics of from the hydrolysates of starch. The extracti on of hydrolysis of sucrose usin g strong cati onic resins. lt is starch from corn (maize) is a complex process. 30 INDIAN J. CHEM. TECHNOL., JANUARY 2001 lOQr-------------------------------, Table I - Relative sweetness of sugars; 15 °C, 15 % solution Sugar Relative sweetness Glucose Fru ctose Cane sugar (sucrose) 100 X Sue rose Fructose (crystalline: 100%) 178 l> Glucoso D-glucosc (crystalline: I 00 %) 70 (I) 0 Fructose Invert sugar ( 100 %) 123 0 E 60 Medium invert (50 %) 110 c HFS (90 wt %) 125-130 0 HFS (55 wt %) 105- 110 Ill HFS (42 wt %) 95- 100 0 Q_ 40 42 DE Glucose syrup 45 E 0 u Maltose 35 Lactose u Res in : RDL-90-7 t5 ::J Flow ra\e.SOml(min Table 2-Typical compositions of commerci al grades of HFS "8 20 pH•S.3 ;Temp = 60'C '- Q_ Suc r ose soln. 300fo(w/v 55 to60 % HFS 90 % HFS %sol ids 77.00 80.00 0~----~~--~~~~==~--~ % ash (sulphated), DS 0.03 0.03 o.o 30.0 % Fructose, DS 55-60 90.00 Tim<2 (min) % D-glucose, DS 4 1-36 7.00 Fig. 2- ln vc rsion of sucrose in a resin bed % other saccharides. DS 4.00 3.00 Moreover, the subsequent processes such as As regards the economics of invert sugar from enzymati c hydrolysis of starch to glucose and its refined cane juice, it may be mentioned that there is partial isomerization to fructose are far more complex no loss of sucrose, like it takes place to the extent of reactions. On the other hand the extraction of sucrose about 2 per cent in molasses in th e case of crystal either from sugarcane or sugarbeet and its inversion to sugar. Consequently the yield is hi gher by about 2 per obtain equ imolar mixtures of glucose and fructose are cent. Moreover, invert syrup contains about 20 per rel atively simple operations. Fig. 4 shows a schematic cent water and possesses higher sweetness. Hence, flow diagram for a commercial process. invert sugar from cane juice is much cheaper than It may be note.d that realizable starch content in crystal sugar. mai ze is about 60 per cent. At its current price of Rs.S,SOO per metric tonne, the material cost of starch Huge Market Potential for In vert Sugar and HFS work s out to about Rs.9,000 per metric tonne. As sweeteners, invert sugar and hi gh fructose Similarly, the practical range of sucrose content in sy rups can replace sucrose 1n almost all its mature cane is 13- 15 per cent. About 2 per cent sucrose appl ications. Functionally, they possess more is lost with bagasse during juice extraction. Hence, the desirable properties than sucrose and are much realizable sucrose content in refined juice may be 12 sweeter. In fact, chemically, invert sugar is same as per cent on an average.