Sugar Industry Technologists Sixty Third Annual Technical Conference

Vancouver, Canada, May 16-19, 2004


Direct Production of Refined Sugar and Value Added

Products from Sugar Cane Mills


By

Dr. Chung Chi Chou

Author/editor: “Cane Sugar Handbook and “Handbook of Sugar refining”

Dr. Chou Technologies, Inc., President

e-mail: Drchouusa@gmail.com

web site: www.esugartech.com


And

Robert J. Kwok

John H. Payne, Inc., President

robertjkwok@gmail.com


Introduction


The cane sugar industry has traditionally been designed to produce raw sugar which is further processed into refined sugar by energy intensive sugar refining processes. In many countries plantation white sugar is produced using sulphitation or carbonation processes. The beet industry on the other hand is designed to produce direct refined sugar. There have been numerous studies conducted on the nature of colorants, polysaccharide and inorganic profile of sugar process streams over the past 30 years. However, very few research priorities have been directed to develop a sugar process that will produce the same quality sugar at cane sugar factories as in sugar refineries. Significant energy can be saved if refined sugars can be produced directly from sugar mills.

Dr. Chou, who was the Managing Director of Sugar Processing Research Institute (SPRI) during 1999-2000, organized and directed a team of scientists and engineers to conduct a research project with specific objective to produce white sugar directly from sugar cane mills. With cooperation from Appelxion of France, the team succeeded in their effort and developed the SPRI–Applexion Technology (SAT) process to produce white sugar with color of less than 200 ICUMSA, using clarified juices from a cane sugar mill in Louisiana. Combining the SAT process (patented) with the new Cti process (Patent pending), refined sugar is produced directly from cane sugar mills. In addition value added antioxidant is recovered as a by-product from the Cti process.


The SAT Process (Patented)


The SAT process is an improvement of the New Applexion Process (NAP) in which clarified juice is ultra filtered through membrane. The SAT process uses two Food Drug Administration (FDA) approved processing aids in combination with the UF membrane filtration to remove non-sugar components, including those colorants and ash, which are preferentially occluded into the sugar crystals during crystallization.

The SAT process was developed to produce sparkling white sugar directly from cane sugar mills without sulphitation, carbonation, and floatation processes. Tests done at SPRI using bench scale boiling pan and at Audubon Sugar Institute using pilot scale pan have produced white sugar color of less than 200 ICUMSA with an input clarified juice of 11,000 ICU and 82 purity. In many sugar producing countries, where the juice quality is poor (below 80 purity), the SAT process will produce sugar between 400 to 750 ICU. In these cases the low color sugar is re-melted and further decolorized before sugar boiling to produce refined sugar. The UF membrane system has a pore size of 0.02 microns. Typical system is designed with permeate recovery between 85 to 90%. The retentate juice from the UF system can be returned to the juice clarifier or sent to an alcohol distillery if one is available at the plant. A flow diagram of the SAT process is shown in Figure below.






The Cti Process (Patent Pending)


The Cti process, a patent pending technology, consists of two special resin systems in series for production of various grades of refined sugar products depending on the feed materials to the process, and for recovery of value added antioxidants. The Cti process is much less capital intensive as compared to other conventional processes and is environmentally friendly with no dark brine waste disposal problem. In comparison the conventional decolorization processes have various disadvantages such as: powdered carbon process has filterability problem, granular carbon system is very capital intensive, and ion exchange resin system has brine disposal problem.


The Cti process flow diagram is shown in Figure 1.







The following various grades of refined sugar can be produced from the Cti process:


  1. White Sugar (80/150 ICUMSA color) via decolorization of sugar mill lime clarified juice to a maximum color of 3000 ICUMSA before sugar boiling. Recovery of value added sugarcane extracts (Antioxidant) is completed via regeneration of resins and deashing of waste regenerants, when needed.

  2. Refined Sugar (12/35 ICUMSA color) from sulphitation sugar factories via decolorization of A, B and/or C sugars (a maximum color of 1000) as shown in Figure 2. The decolorized sugar liquor with color of 150/200 is then crystallized to give refined sugar. Value added sugarcane extracts (antioxidant) is recovered via regeneration of resins and deashing of waste regenerants.





  1. Refined Sugar (12/35 ICUMSA color) from VLC raw sugar without conventional decolorization process (Figure 3). The color of VLC raw sugar should be less than 1000 ICUMSA color.


  1. Liquid Sugar (15/35 ICUMSA color) via decolorization of “off” white sugar (500 max. ICUMSA color) from sulphitation factories to a color of 50/100 color, which can then be further decolorized by powdered activated carbon to 15/35 color of sugar liquor for the beverage industry (Figure 4). Value added sugarcane extracts (antioxidant) can also be recovered via regeneration of resins as above.



  1. Refined Soft Brown Sugar This product can be manufactured from tail end strike of refined/white sugar boiling (Figure 3 & 5)


  1. As an excellent alternative to conventional granular carbon/bone char/ion exchange resin for final decolorization before evaporation and crystallization to produce refined sugar in a typical refinery. Sugar liquor after phosphatation/carbonation can be fed directly to the Cti resin system to avoid further need of GAC or PAC decolorization. (Figure 5)





  1. In Conjunction with SAT Process to produce 100% refined sugar from sugar mills particularly when the clarified juice color is higher than 11,000 ICU and purity is lower than 77 (Figure 6).




  1. Energy Cane Sugar Plant - Combination of SAT and Cti processes is particularly applicable for an energy cane plant where electricity, alcohol, fertilizer and value added antioxidants are the major products (Figure 7). In the Energy Cane sugar mill the process of producing refined sugar is greatly simplified since only two boiling system is used in the raw house. The retentate juice from the SAT system is added to the B-molasses and used as feedstock to produce fuel ethanol at the alcohol distillery. The refined sugar crystallization is also simplified with no Remelt recovery system. The #2 syrup from the continuous centrifugal is returned to either the Cti column, or is sent back to the raw house to be reprocessed into A massecuite. The filtered juice from the vacuum mud filter can also be sent back to the distillery for production of fuel ethanol.







Antioxidants from Sugarcane


Recent research has demonstrated the relationship between the aging process and the damaging effects of free radicals on tissue cells, and the beneficial impact on blood plasma antioxidant capacity of the increased daily intake of antioxidant-rich foods. In recent publications (1, 2), the ORAC analysis was performed on a series of sugarcane products with the results ranging from some 5,000 (ORAC units/100g dried solids) to over 35,000, indicating strong antioxidant properties, comparable, if not superior, to those previously reported for the top-antioxidant-rich fruits.


USDA scientists have recommended a daily intake of 3,000 to 5,000 ORAC units. The Oxygen Radical Absorbance Capacity (ORAC) method, to quantify the antioxidant property, was developed by USDA research laboratories several years ago, and since has then been used to rank (ORAC units/100g) common foods. Prunes (5,770), raisins (2,830), and blueberries (2,400) top the list, trailed by such health food industry favorites as kale (1.770), spinach (1,260) and Brussels sprouts (980) (3).


Antioxidants in concentrated sugarcane extracts obtained from cane juice, using the Cti process was found to contain over one million ORAC units/100g dried solids (1, 2). Table below shows analysis of antioxidant for three extracts (2 from USA and 1 from China). Besides ORAC units, analysis was also performed on polyphenols and cathechin. The % of polyphenols is comparable to that of grape seeds extract.




Antioxidant Analysis


ORAC unit on dried basis, other on samples as received basis at about 67 brix


Extracts (origin)

ORAC unit/100 grams

Polyphenols %

Total cathechin %

#1 (USA)

1.26 million

19.05

1.26

#2 (USA)

1.36 million



#3 (China)

2.61 million

17.47

0.80




In two Japanese studies published in 2001 and 2002 Sugar Technologists Technical Proceedings (4, 5), sugarcane extracts were found to have many other beneficial physiological functions as shown below:


  1. Phylactic Effects (promotion of resistance against virial and bacterial infections)

  2. Vaccine Adjuvant Effect (stimulates the immune response and increase effectiveness of the vaccine)

  3. Protection Effects on liver injuries

  4. Antioxidative Activities (one gram contains 12,000 ORAC units)

  5. Enhanced Growth of animal

  6. Anti-coccidial infection in chickens


Extraction of Antioxidants from Sugarcane Using Cti Process


The extraction process includes the following steps:


  1. Decolorization of clear liquor, and removal of antioxidants, being part of colorants, by filtering through an adsorbents resin. The decolorized and antioxidants depleted clear liquor is returned back to the factory for crystallization to produce various food sugar products.

  2. Recovery of antioxidants from and regeneration of, adsorbent resin by washing the resin with aqueous sodium hydroxide solutions, etc., producing antioxidant extract solution containing color, antioxidants, sodium and hydroxyl ions.

  3. Removal of sodium and hydroxyl ions by filtering the above antioxidant extract solution through cationic exchange resins, producing antioxidant enriched functional food products.

  4. Regeneration/reactivation of spent cationic exchange resins by passing hydrochloric acid solution through spent cationic exchange resins.


The yield of antioxidants range from 0.01% to 0.02% on the weight of cane depending on the color of feed material to the Cti process.


The use of adsorbent resin in studies of the nature of sugar colorants and for decolorization has been previously reported (6, 7)


Test Results


Tests 1 to 4 show the results of extraction and decolorization experiments performed on sugar cane syrup.



Test 1. – Extraction of Antioxidant from Sugar Cane Syrup


Adsorbent: Vendor A


Feed: Louisiana Sugar Cane Syrup, pH 6.2, Brix 46.5, Color 8,400 ICU


Fraction

pH

BV

Color*

% Decolorization

F-1

7.5

1.0

747

91

F-2


0.7



F-3

6.3

0.7

1183

86

F-4


0.9



F-5


0.8



F-6

6.1

0.4

2498

70


* Normalized to 46.5 Brix





Test 2 – Extraction of Antioxidants from Sugar Cane Syrup


Adsorbent: Vendor B


Feed: Louisiana Sugar Cane Syrup, Brix 35-40, Color 8,100 ICU


Fraction

pH

BV

Color**

% Decolorization

F-1


2.6

3997

50

F-2


2.2

4485

44.6

F-3


2.2

6687

17.3


** Normalized to 35 Brix



Test 3 – Decolorization Experiment


Adsorbent Resin: Vendor A


Feed: Affined Raw Sugar Liquor, Color 402 ICU, Brix 35-40


Fraction

BV

Color

% Decolorization

F-2

4

107

73

F-5

10

158

61

F-8

16

168

58

F-12

24

198

51



Adsorbent Resin: Vendor B


Fraction

BV

Color

% Decolorization

F-2

4

222

45

F-5

10

276

31

F-8

16

286

29



Test 4 – Decolorization Experiment


Adsorbent Resin: Vendor A


Feed: Affined Raw Sugar liquor, Color 310 ICU, Brix 35-40


Fraction

BV

Color

% Decolorization

F-3

6

121

61

F-7

14

152

51

F-21

42

198

36


Adsorbent Resin: Vendor B


Fraction

BV

Color

% Decolorization

F-3

6

216

30

F-7

14

247

20

F-21

42

277

11



The above test results indicate that the decolorization capacities of resins vary significantly depending on the suppliers. It is obvious that the higher the syrup feed color, the higher the recoverable antioxidants.



Antioxidant Products from Sugarcane Extract


The following are examples of the use of antioxidants in food formulation/application.


  1. Antioxidant as dietary daily supplement


Based on USDA scientists a daily requirement of 4,000 ORAC is needed.

Concentrated sugarcane extract contains 12,000 ORAC/g

1 gram = 3 capsules (soft gels)

1 kilo of antioxidant extract will make 3,000 capsules of 4,000 ORAC. It has been estimated that the market price of the antioxidant from the sugar cane may be as high as US$ 60/Kg.


1 gram of concentrated antioxidant also contains about 250 mg of polyphenols

Each capsule would therefore contain about 80 mg of polyphenols. This is comparable to grape seed extract.


  1. Antioxidant fortified/enriched dietary syrup


Add antioxidant into edible molasses to make 1,500 ORAC per table spoon (15 ml). One table spoon a day will meet about 40% of daily requirement.


  1. Antioxidant fortified/enriched soft brown sugar


1 Kg antioxidant to mix with 3,000 lbs of soft brown sugar. This will make a soft sugar fortified with 4,000 ORAC/lb of sugar.






Conclusion


The SAT and Cti processes have been shown to be attractive technologies for production of various refined sugar products and antioxidant directly from cane sugar mills. The use of these processes will significantly reduce energy consumption in refined sugar production and alleviate environmental problem. Recovery of value added antioxidant during the decolorization process is an added economic advantage.







References Cited


  1. Saksa and Chou, Antioxidant Properties of Sugarcane Extracts, First Biennial World Conference on Recent Development in Sugar Technologies, May 16-17, 2002, Florida, USA.

  2. Koge, Saska and Chou, Asian Functional Food (Nutraceutical Science & Technology Series) Marcel Dekker Publishing Company – pending, 2004

  3. Top antioxidant foods, USDA Agriculture Research Magazine, Feb 1999 Issue

  4. Nagai, Mizutani and Iwabe, 2002 Physiological Functions of Sugarcane Extracts. Proc. Sugar Ind. Technol. pp 97-104

  5. Koge, Nagai, Ebashi and Ewabe, Physiological Functions of Sugarcane Extracts-Growth Promotion, 2002. Proc. Sugar Ind. Technol. pp 285-292

  6. Chou and Rizzuto, The acidic Nature of Sugar Colorants, Proceedings of the1972 Technical Session On Cane Sugar Refining Research, Agricultural Research Service, U. S. D. A.

  7. Rothchild, Decolorization by Adsorption with A non-Functional Resin, 1993 Proc. Sugar Ind. Technol. pp 305-324.