Đồ án Production of fructose syrup from Jerusalem artichoke

totally fermented by colonic microflora. The short-chain fatty acids and lactate produced by fermentation contribute 1.5 kcal per gram of inulin or oligofructose. Inulin and oligofructose are used to replace fat or sugar and reduce the calories of foods like ice cream, dairy products, confections and baked goods.  Other carbohydrates: Little information is available on the concentration of various other carbohydrates in the tuber and tops of the Jerusalem artichoke. Stauffer et al. found that cellulose content of the tuber (as measured by acid detergent solubilization) ranged from 33-40% in carbohydrate-extracted pulp (dry basis) for four strains. Hemicellulose levels were found to be between 2.3 and 13%. The cellulose content in the aerial parts was found to be 20-40% of dry weight. The hemicellulose content of the tops has been observed to decrease as the plant develops, evidence of pectin and starch in the tubers and tops of the artichoke have been mentioned in the literature; however, quantitative data was not available.  Dynamic of accumulation of sugars in tops and tubers: Table 8 shows the changes in water-soluble carbohydrate accumulation and the distribution between tops and tubers of nine late-maturing cultivars. The sugars were stored in the stalks until the end of September and then, during October, were rapidly transferred to the tubers. The total sugar content of the plants achieved a maximum value in September during flowering and then remained constant up to the middle of November. Only when the rainfall in September was sufficient to promote increased photosynthesis, as in 1984, was there a further increase of sugar in the tubers. In an early-maturing cultivar (D-19 of INRA collection) the sugar accumulation and distribution were similar, but occurred a month earlier. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 23 Table 8: Changes in accumulation of water-soluble carbohydrates in tops and tubers of Jerusalem Artiochoke. Average of nine-maturing varieties.  Location and development of polyfructans: It has been found that inulin and inulides are present in all parts of the artichoke plant, with the possible exceptions of the upper parts of stems, petioles, and leaves. Bachmanowa, findings show also that carbohydrate distribution in the tuber is non-uniform, with a higher concentration in the central core (~16-18%) and concentration decreasing as the radial distance from the centre increases (to about 8-10% w/w, wet basis). Though the mechanisms and factors which control fructose metabolism in the Jerusalem artichoke are still not completely understood, a fairly complete model has been put forth by Edelman and Jefford. The model is summarized in Figs 10 and 11. These researchers give special significance to the trisaccharide, lV-fructosylsucrose (FS) as a key intermediate in the production of long-chain inulides. This intermediate is formed by the transfer of a fructose moiety from one sucrose molecule to another, which liberates glucose (see Step 1, Fig. 10). The step is catalyzed by sucrose-sucrose 1 F -fructosyltransferase (SST). The terminal fructosyl residue on the trisaccharide is transferred to a sucrose molecule within the storage vacuole by β(2→1)Fructan: (2→1)fructan 1-fructosyltransferase (FFT) located on the tonoplast (Step 2). Repeated transfer of a fructose monomer to the growing polyfructan occurs (Step 3) until chain termination takes place. This sequential transfer can lead to inulin (dp~35) since precipitated sphero-crystals of this material have been optically visualized within the vacuole. Both SST and FFT are specific for their substrates and contain no hydrolytic activity. Thus, hydrolytic inulases β(2 ~ 1)Fructan 1-fructanohydrolases are also present, which catalyze the depolymerization of the polyfructans. Two such enzymes with similar properties have been described (hydrolases A and B), which are distinguished by their relative activities on inulin and the inulides. These enzymes break only the β(2 ~ 1) linkage between a terminal fructosyl group and its adjacent fructose residue (see Fig. 11, Step 1). Fructose is then transported into the cell cytoplasm at the expense of energy (Step 2). The FFT enzyme at this point is free to transfer fructosyl groups among the chain ends of the oligosaccharides within the vacuole, while PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 24 hydrolases continue to liberate fructose. Therefore, the final result is a rapid decrease of the average chain length of the polymers. It is found that fluctuations in chain length occur with no net loss of carbohydrate from the tuber. With this in mind, and the fact that all inulides and inulin are terminated by a sole glucose residue, it is apparent that some mechanism must allow for the interconversion of glucosyl and fructosyl residues since their ratios must change. The Edelman and Jefford model can account for this by hexosephosphate isomerase activity in the traditional pathways of sucrose synthesis (Step 4 in Fig. 10; Step 3 in Fig. 11). At the onset of tuber initiation in late summer, there is a great shift of sucrose translocation toward the subterranean parts of the plant. The tubers rapidly enlarge, with a concomitant increase in polyfructans. FIG 10. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 25 The SST enzyme appears to be the controlling factor of this process. This is supported by the findings that SST activity disappears rapidly from the tubers when growth has ceased. In addition, SST activity quickly falls off within a few days when growing tubers are freshly harvested. Invertase activity has also been shown to increase substantially during tuberization; however, Edelman and Jefford dispute its role in fructan metabolism. The hydrolytic enzymes also increase in activity during tuber maturation yet remain at high levels during dormancy. When tubers are freshly harvested and stored at low temperatures (~ 2°C), the hydrolase activity of the tissues seems to be accelerated. Field studies which have followed the transitory levels of various carbohydrates during Jerusalem artichoke development can be easily explained in terms of these enzymatic effects. In studies on the time dependent concentration of inulides of varying length during plant maturation it was found that separate polyfructans with DP > 7 could not be quantified due to insufficient resolution given by the gas-liquid chromatographic system used for analysis. However, it could be seen that monosaccharides and oligomers of DP 1-5, though initially present in large amounts, steadily decreased during plant maturation and tuber filling. Concurrently, longer-chain inulides and inulin increased in concentration. This process is reversed at approximately the 16th week FIG 11. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 26 after sprouting (i.e. tuber maturation), at which point high-molecular weight carbohydrates are broken down to short-chain oligomers. These results closely follow the anticipated flux in fructosyltransferase and hydrolase activity. As a consequence of general chain length reduction occurring with little change in total carbohydrate levels, it would be expected that fructose/glucose (F/G) ratios should decrease upon termination of tuber filling. This result has been observed by a number of workers is shown in Table 9. Fleming and GrootWassink have reported constant F/G ratios in their study on the development of the Jerusalem artichoke. However, this observation is considered as anomalous and is attributed to specific agronomic conditions such as rainfall. It has been found that relative fructose concentrations rarely fall below 70% during normal fall harvest periods. A typical comparison of the relative abundance of monosaccharides, inulides, and inulin is shown in Table 10 for two strains of tubers grown in three successive seasons. The level of monosaccharides is generally low, although this may vary in relation to enzyme activity. Since the polymerization mechanism releases, free glucose whereas the hydrolytic steps liberate fructose, the relative concentrations of these monosaccharides are highly dependent upon the age at harvest and storage time of the sample. The levels of oligosaccharides and inulin are also closely related to these parameters for reasons discussed earlier. It is important to note the extreme variations in carbohydrate make-up witnessed across the two artichoke strains and, within the same strain, across the three seasons. It is apparent that the variety of the plant and prevailing seasonal conditions in the year it is grown elicit a great effect on Jerusalem artichoke composition. It has been reported that glucose and fructose are generated in the leaves of the Table 9: PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 27 artichoke plant and polymerization first occurs in the stem as the carbohydrate is translocated toward the developing tubers, thus, the interest has been placed on the artichoke stalks as possible sources of carbohydrate in addition to (or in place of) the tubers. 1.2.2. Protein content: Total nitrogen and protein levels in the Jerusalem artichoke remain relatively constant during plant growth. Table 11 compares the concentration of protein and various amino acids contained in the tubers and tops with that of potato tubers and forage beet roots. It was found that aerial parts of the artichoke contain a greater proportion of protein than do the tubers; however, crude protein levels in the tops may decrease if harvesting is substantially delayed. The Jerusalem artichoke contains a similar amount and distribution of amino acids as the fodder beet but amino acid levels in the potato tuber are almost consistently greater. The quality of this protein for human and livestock consumption will be discussed in the second part of this review. Table 11: 1.2.3. Minerals: The tubers of the Jerusalem artichoke contain a considerable amount of minerals. According to Conti and Eihe, ash content in the tuber is 1.2-4.7% and 4.7% of dry weight respectively. This value is equivalent to the ash content found in potato tubers. Reports by Rashchenko, that mineral content of the tuber increases to 32% of dry weight during plant growth probably reflects the consumption of storage carbohydrates in the tuber rather than any increases in ash levels. Table 10: PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 28 Vegetative biomass of this plant is found to contain two to three times the amount of ash than the tubers. Leaves are especially abundant in ash, where 12-16% of the total dry matter is of this material. A comparison between the mineral composition of the Jerusalem artichoke and the potato is given in Table 12. The level of each component in both plants is similar in most cases with the exceptions of Na, Fe, and Si oxides, the increased levels of Fe2O3 (triple that found in the potato) give the artichoke significance for the prevention of anaemia in livestock. 1.2.4. Vitamins: The levels of Vitamin C and H-carotene (precursor to Vitamin A) are found at their maximum during July and August for both the tubers and tops. Leaves exhibit the highest concentrations in July, with 371 mg/kg (d.m.) and 1662 mg/kg (d.m.) for carotene and Vitamin C respectively. The stems are generally 3-10 times lower in these concentrations than the leaves. The tubers have been found to contain the lowest levels of Vitamin C at 150 mg/kg (d.m.). Although the vitamin content of the tuber is much lower than that found in the leaves, it still exceeds values reported for potato tubers by approximately a factor of four. These results are highly dependent on the phase of development, climatic conditions and cultivation characteristics. 1.2.5. Moisture: Moisture content within the tuber and forage material is extremely dependent upon the irrigation and precipitation characteristics during cultivation of the crop. Due to the thin epidermal layer which surrounds the tuber, the Jerusalem artichoke is poorly protected against moisture loss. Thus, water content of the plant may represent only the current equilibrium between tubers and the surrounding soil. However, no evidence has been presented against the possibility that moisture content is pre-determined during tuber growth. Generally the level of moisture fluctuates closely at about 80% of the total tuber wet weight. The pH of the press juice obtained from the tubers is reported to be approximately 6.5. A number of organic acids have been identified in the juice, which include p-hydroxybenzoic acid, chlorogenic, vanillic, gentisic, p-coumaric, caffeic, and ferrulic acids. The relative levels of these Table 12: PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 29 acids are found to be variable, especially during storage, where total and organic acids have been reported to increase over a period of 5 months at 20°C. 2. Inulinase: Inulin is hydrolysed by enzymes known as inulinases. Inulinases are classified into endo- and exo-inulinases, depending on their mode of action. Endo-inulinases (2,1- -D-fructan fructanohydrolase; EC 3.2.1.7) are specific for inulin and hydrolyse it by breaking bonds between fructose units that are located away from the ends of the polymer network, to produce oligosaccharides. Exo-inulinases ( -D-fructohydrolase; EC 3.2.1.80), split terminal fructose units in sucrose, raffinose and inulin to liberate fructose (Onodera and Shiomi 1988; Uchiyama 1993; Ohta et al.2002). FIG 12. Mechanism of the inulin hydrolysis by inulinases 3. Saccharomyces cerevisiae: Saccharomyces cerevisiae is a unicellular organism. The cells have a diameter of approximately 3-5 micrometer and resemble plant and animals cells with respect to complexity in spite of their small size. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 30 FIG 13. Micrographs of S. cerevisae Scientific classification:  Kingdom: Fungi  Phylum: Ascomycota  Subphylum: Saccharomycotina  Class: Saccharomycetes  Order: Saccharomycetales  Family: Saccharomycetaceae  Genus: Saccharomyces  Species: S. cerevisiae Life cycle: There are two forms in which yeast cells can survive and grow: haploid and diploid. o The haploid cells undergo a simple life cycle of mitosis and growth, and under conditions of high stress will generally simply die. o The diploid cells (the preferential “form” of yeast) similarly undergo a simple life cycle of mitosis and growth, but under conditions of stress can undergo sporulation, entering meiosis and producing a variety of haploid spores, which can proceed on to mate. Nutritional requirements: All strains of S. cerevisiae can grow aerobically on glucose, maltose, and trehalose and fail to grow on lactose and cellobiose. However, growth on other sugars is variable. It was shown that galactose and fructose were two of the best fermenting sugars. The ability of yeasts to use PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 31 different sugars can differ depending on whether they are grown aerobically or anaerobically. Some strains cannot grow anaerobically on sucrose and trehalose. All strains can utilise ammonia and urea as the sole nitrogen source, but cannot utilise nitrate since they lack the ability to reduce them to ammonium ions. They can also utilise most amino acids, small peptides and nitrogen bases as a nitrogen source. Histidine, Glycine, Cystine and Lysine are, however, not readily utilised. S. cerevisiae does not excrete proteases so extracellular protein cannot be metabolized. Yeasts also have a requirement for phosphorus, which is assimilated as a dihydrogen phosphate ion, and sulfur, which can be assimilated as a sulfate ion or as organic sulfur compounds like the amino acids methionine and cysteine. Some metals like magnesium, iron, calcium, zinc also are required for good growth of the yeast. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 32 Chapter 2: Processing technology of fructose syrup from Jerusalem artichoke: Production-line schema PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 33 Chapter 3: Processes in the fructose syrup production-line from Jerusalem artichoke I. Preliminary treatment: 1. Aim: Preparation 2. Transformation of raw materials: 2.1. Physical changes: The mass of material decreases because impurities are eliminated. The shape of material is a little bit changed due to this treatment. 2.2. Chemical changes: Moisture content of material increases, the content of solid solubles decrease because of the diffusion in the washing treatment. 3. Affecting factors: Time requirement for the washing: If time is long, the impurities are lesser. However, composition and texture of the feedstock are changed and sometimes they are negative. Machine and methods of the treatment also effect on the operation. 4. Technical parameters: FIG 14. Washing equipment PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 34 Water temperature: 60 o C – 70oC. Time required: 1 – 2 minutes. II. Cutting: 1. Aim: Preparation 2. Transformation of raw materials: The mass of material decreases. The shape of material is changed due to this treatment. The size is reduced. 3. Affective factors: Texture of the material (firmness, crispness…) effects on the operation and the choosing method. Equipment and methods of the cutting also affect on this treatment. III. Milling: 1. Aim: Preparing the feedstock for the later extraction. We are known that the more surface areas you have, the easier the extraction will be. 2. Transformation of raw materials: Physical changes are sufficient. The size is decreasing while surface areas increase. The temperature of material rises in the milling. 3. Affective factors: The size of the tuber particles and extraction temperature usually are controlled to maximize the extractability of inulin and fructans while minimizing the extraction of low molecular weight nitrogen-containing material and minerals. The type of machine and parameters also affect on the efficient of the milling. 4. Technical parameters: The size of material after milling is less than 0.125 mm. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 35 FIG 15. Operating principle of Hammer mill Operating principle of hammer mill: The material to be crushed enters the hammer mill through gravity feed hopper having an adjustable slide to control the feed material. The material is crushed between the hammers and serrated liners. A powerful blower in hammer mill continuously sucks the ground material through a screen classifier and conveyed through the pipe into the cyclone for bagging. The blower maintains constant airflow in the Hammer Mill chamber in order to obtain a cool product and continuously cleans the screens, thus increasing the output. Particle size of the ground material can be varied over a large range by using sieves with the desired openings of hammer mill. IV. Extraction: 1. Aim: Getting the inulin from Jerusalem artichoke. 2. Transformation of raw materials: 2.1. Physical changes: The temperature of materials increases. The elevated temperature also increases the rate of solubilization of the inulin, inactivates any enzymes present which may interfere with later processing and results in extraction of lower quantities of nitrogen-containing extractables. The diffusion of water on the mass of material and the diffusion of dissolved agents on the water. The viscosity of the solution increases because the macromolecules-inulins rise. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 36 2.2. Chemical changes: Several reactions can occur such as Maillard, hydrolysis, browning reaction… 2.3. Physical chemical changes: Solid phase changes into liquid phase The evaporation of volatile agents 3. Affective factors: The size of materials in particularly or the surface area in generally affects on the extraction as mentioned on the milling part. The size of the tuber particles and extraction temperature usually are controlled to maximize the extractability of inulin and fructans while minimizing the extraction of low molecular weight nitrogen-containing material and minerals. The temperature of solvent:  If the temperature is high, the extraction process occur quickly but the cost of the energy is also high;  If the temperature is low, the extraction process occur slowly, the productivity is low The extraction time, the solvent:solid ratio also effect on this operation. 4. Technical parameters: Method: Conventional extraction (1 stage extraction). Solvent: Hot water.  Ernst Hoeln et al. (1983): Inulin is only sparingly soluble in water at temperatures below about 50 0 C. At higher temperatures, however, the solubility increases substantially, so that it is preferred to effect the solubilization at an elevated temperature above about 50 0 C.  Suitable to that viewpoint, Wei Lingyun et al. (2007) assumed that the optimal conditions for maximizing inulin extraction yield (83.6%) were at natural pH for 20 min at 76.65 0 C and solvent:solid ratios of 10.56:1 (v/w). While PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 37 V. Filtration: 1. Aim: Removing solid phase material, such as solid and cell debris, from the aqueous inulin solution. 2. Transformation of raw materials: Physical changes: are predominant  The mass and volume of material decrease.  The temperature of material also decreases. 3. Affective factors: Properties of materials: The viscosity of filtered solution is high, time requirement for this step is also long. Temperature for the filtration: The higher temperature is, the easier filtration is. That due to viscosity decreases when temperature increases. However, the quality of the filtered solution is lesser because of the undesirable reactions with or without enzyme catalysts. Pressure used for filter, other parameters and equipment for the filtration also effect on the process. 4. Technical parameters: In order to remove the phase from the solution, we can use cheese-cloth or tissue paper for the filtration. In industry, they use plates and frames equipment with cheese-cloth for thix process. FIG 16. Operating principle of plates and frames equipment PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 38 FIG 17. Plates and frames VI. Ultrafiltration: 1. Aim: Purify and concentrate the filtered inulin from other contaminants. There are two mechanisms for two ultrafiltration steps in the processing.  Firstly, after filtration step, the filtered inulin solution then is subjected to a simultaneous concentration and purification step while amino acids, peptides, minerals and other contaminants of low molecular weight than inulin and related fructans are removed from the solution. This simultaneous concentration and purification step may be affected by any convenient membrane technique whereby the contaminants are allowed to pass through the membrane with part of the aqueous phase while the inulin and related fructans are retained in the concentrated solution.  Secondly, after hydrolysis step, the hydrolysis step results in a fructose solution which contains higher molecular weight species, including unhydrolyzed or only partially hydrolyzed inulin and related fructans, as well as the fructose, glucose and minor amounts of higher saccharides which are formed by hydrolytic breakdown of the inulin. The higher molecules will be withdrawed and fructose will be obtained from this process. 2. Transformation of raw materials: 2.1. Physical changes: The mass and volume of material decrease. The temperature of material also decreases. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 39 2.2. Chemical changes: Constituents of material change inconsiderable. However, concentration of chemical compounds significantly changes. 3. Affective factors: A molecular weight cut-off in the range of about 500 to about 2000 usually is employed. At the lower end of this range, a high yield of inulin and related fructans of low purity is obtained while, at the upper end of this range, a low yield of inulin and related fructans of high purity is obtained. The extent to which the inulin solution is concentrated depends upon purity and yield considerations. As the degree of concentration increases, the purity increases but the yield decreases as some fructans pass through the membrane. On the other hand, as the yield increases, the purity decreases due to the effects of concentration/equilibrium dynamics on non-fructose structures. 4. Technical parameters: A molecular weight cut-off in the range of about 500 to about 2000 usually is employed. FIG 18. Ultrafiltration equipment PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 40 4.1. First ultrafiltration step: A molecular weight cut-off in the range of about 1000 has been found to provide a convenient balance of yield and purity. The extract is filtered under pressure (about 50 psi) until about 10% of the original volume remained in the cell. The filtrate fraction is discarded. The retentate fraction is withdrawn from the cell, and the cell was wash with an equal volume of distilled at 40 o C to remove any remaining inulin. The washed water was mixed with the retentate fraction. 4.2. Last ultrafiltration step: The same ultrafiltration membrane is used, p = 50 psi. Filter until about 30% of the volume remained in the cell. VII. Hydrolysis: Conventional method: 1. Aim: Break down the inulin and related fructans to produce fructose syrup. 2. Transformation of raw materials: 2.1. Physical changes: The viscosity of feed material decreases. The temperature of feed material increases. 2.2. Chemical changes: Constituent and concentration of feed material change. The hydrolytic reaction mainly occurs. Inulin and related fructans are broken down to fructose and glucose. There are some reactions: Maillard, browning reaction… 2.3. Chemical physical changes: Boiling and evaporation of water PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 41 2.4. Biological changes: Micro-organisms are inhibited 2.5. Chemical biological changes: Inactivating enzymes. 3. Affective factors: Temperature, pH and other conditions of feed material effect on the operation. Temperature increases, pH decreases, the hydrolysis happens easilier. Property of feed material and equipment also effect on the process. 4. Technical parameters:  Z. Duvnjak et al. (1987): - Catalyst: Sulphuric acid (H2SO4) - pH 2.6 - Temperature 800C - Time 135 minutes  Other researchers, S. Schorr-Galindo et al. (1995), have a different hydrolytic regime: - Catalyst: Sulphuric acid (H2SO4) - pH 2 - Temperature 1200C - Time 30 minutes  This method (using acid as a catalyst) occurs under stringent regime (either high temperature or long time). As the result, the yield decreases, the quality of the hydrolysate also lessens. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 42 Inulinase enzyme method: 1. Aim: Break down the inulin and related fructans to produce fructose syrup. 2. Transformation of raw materials: 2.1. Physical changes: The viscosity of solution decreases. 2.2. Chemical changes: The mainly reaction is enzymatic hydrolysis reaction. 2.3. Biological changes: Micro-organisms are inhibited because benzoic acid is added in the operation. 3. Affective factors: Temperature, pH and other conditions of feed material effect on the operation. Temperature increases, pH decreases, the hydrolysis happens easilier. Property of feed material and equipment also effect on the process. Kind of enzyme: single enzyme or mixed enzymes, free enzyme or immobilized enzyme, endo or exo enzyme also affect on the process. 4. Technical parameters:  Ernst Hoehn et al. (1983) use free inulinase from Kluyveromyces fragilis. The inulinase was in the form of a preparation containing 1000 units/ml of extract wherein 1 unit liberates 1 g of hexose per minute using sucrose as a substrate at pH 5 and 50 0 C. - 0.15% (v/v) inulinase - pH 5 – 6 - Temperature 500C - Time 2 hours  Sarote Sirisansaneeyakul et al. (2007) use mixed inulinases from Aspergillus niger and Candida guilliermondii. The inulinase activity was 0.2 unit/g substrate PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 43 wherein 1 unit of inulinase activity was defined as the quantity liberating 1µmol of fructose in 1 minute, from 0.5% (w/v) solution of inulin standard in 0.5M McIlvaine buffer at pH 5.0 and 40 0 C. - Initial substrate concentration of about 50 g/l - The mold and the yeast enzymes is mixed in the inulinases activity ratio of 5:1 (but the total activity of inulinases used in the reaction was always the same at 0.2 unit/g) - pH 5.0 - Temperature 400C - Time 25 hours - They claimed that the mold and yeast crude inulinases, mixed the activity ratio 5:1 proved superior to individual crude inulinases in hydrolyzing inulin to fructose because the enzyme mixture provided a better combination of endo- and exo-inulinase activities than did the crude extracts of either the mold or the yeast individually. [S] = inulin concentration, I = inulinases, YF/S = fructose yield based on inulin, QF = volumetric productivity of fructose – ; Where [S0] and [St] are concentrations of inulin at time 0 and t, respectively – ; Where [Ft] and [F0] are concentrations of fructose at time t and 0, respectively Table 13: PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 44 S0 was always measured by the phenol–sulfuric acid method prior to hydrolysis. For above calculations, St was estimated as follows: Where the concentrations of the products with DP1–5 were estimated by HPAEC–PAD 2.1. C. H. Kim et al. (1989) research on inulinase immobilized on chitin for production of fructose syrup form Jerusalem artichoke. Commercial inulinase (3366 units/ml) was added on chitin (336.6 units/g of chitin). After immobilization, 23% initially added activity was recovered in a chitin and inulinase complex (76.8 units/g of chitin). One unit of inulinase was defined as the amount of enzyme which liberates 1 micromole of reducing sugar per minute at 50 0 C and pH 5.0. - Batch hydrolysis: Jerusalem artichoke juice containing 100 g/l of total carbohydrate was incubated with inulinase immobilized on chitin at 40 0 C, the extent of hydrolysis attained 90% (D-fructose:D-glucose = 86:14) in 10 hours and 77.5 g/l of D-fructose was produced from the juice. - Continuous hydrolysis: The continuous hydrolysis of Jerusalem artichoke tuber juice was carried out in a packed bed reactor with inulinase immobilized on chitin at 40 0 C. Jerusalem artichoke juice containing 100 g/l of total carbohydrate was fed through the column using peristaltic pump. The maximum volumetric productivity of 61 g/l.h was obtained at residence time of 0.9 hour and conversion yield of 55%. FIG. 19 PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 45 2.2. Wei Wenling et al. (1999) use immobilized intracellular inulinase from Kluyveromyces sp. Y-85 to produce fructose syrup from Jerusalem artichoke. A portion of pro-treated macro-porus ionic polystyrene bead (D201-GM resin) was added to enzyme solution (50 units/ml). After immobilization, 320.5 units/g (wet weight) of the support and 62% were achieved. One unit of inulinase was defined as the amount of enzyme producing 1 mol of reducing sugar per minute at pH 5.0 and 50 0 C. - Continuous hydrolysis: Use packed bed column reactor 4.5% (w/v) of fructans solution (pH 5.0) from Jerusalem artichoke extract Temperature 500C Dilution rates of 1.7 – 6.8 h-1 The hydrolysis (%) of fructans was 100 – 75%, respectively and the maximum volumetric productivity (Qp) in the bed reactor 234.9 g reducing sugars.l -1 .h -1 If we concern about product yield, this volumetric productivity (234.9 g/l.h) is obviously higher than that obtained by C. H. Kim et al. (1989) (61 g/l.h). (The qualities of products of two immobilization methods are not mentioned) FIG. 20 PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 46 FIG 21. Hydrolysis of fructans of Jerusalem artichokes as a function of dilution rate in a packed bed column reactor containing immobilized inulinase from Kluyveromyces sp. Y-85. Fructan solutions (pH 5.0) of different concentrations were hydrolyzed continuously at 50°C. Symbols for fructan concentration: 2.25% (♦) and 4.5% (■) VIII. Propagation: 1. Aim: Making an optimal condition for micro-organisms’ propagation and supplying enough biomass rates for the fermentation. 2. Transformation of raw materials: Microbial changes are predominant. Micro-organisms use the food, nutrients for:  Growth  Propagation 3. Affective factors: Properties of inocula and conditions for the process: Each inoculum has an optimal condition. In the optimal condition, the growth and propagation are maximum. 4. Technical parameters: Medium for preparation of the inocula consisted of: - Glucose 10 g/l - Yeast extract 30 g/l - Peptone 3.5 g/l - KH2PO4 2 g/l PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 47 - MgSO4 1 g/l - (NH4)2SO4 1 g/l - And distilled water Growth was carried out at 33 0 C for 30 hours. This time was sufficient to ensure that the cells were in the exponential growth phase. FIG 22. Propagation equipment IX. Sterilization: 1. Aim: Creating a sterile media in order to prepare for fermentation. 2. Transformation of raw materials: 2.1. Biologycal changes: are predominant Inhibiting and destroying the microbial cell. 2.2. Physical changes: Evaporation of water in the feed material. Temperature of the media increases highly. Mass weight of the food material also decreases. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 48 2.3. Chemical changes: Some enzymatic reactions are inhibited. Several non-enzymatic reactions occur such as Maillard, hydrolytic, desamination reactions. 3. Affect factors: Conditions of the process: temperature, time of the sterilization. Methods and kinds of equipments using for the sterilization: batch or continuous sterilization, autoclave, retorted autoclave or UHT… Properties of the feed material also affect the operation. 4. Technical parameters: 2.3. Media: Hydrolyzed artichoke solution ( glucose 3.9% w/v + fructose 13.6% w/v) - 30 g/l yeast extract - 3.5 g/l peptone. - 2 g/l KH2PO4. - 1 g/l MgSO4. - 1 g/l (NH4)2SO4. - pH = 5.5 ÷ 5.6 with KOH 4N. - to = 110oC for 15 mins. 2.4. Media: hydrolyzed artichoke solution (glucose 4.11%÷4.55% [w/v] + fructose 13.4%÷14.44% [w/v]). - If the hydrolyzed artichoke solution is supplemented with glucose, the glucose concentration will be 15.7% w/v. - 10mM of CaCl2. - to = 115oC for 15 mins. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 49 FIG 23. Sterilization equipment X. Fermentation: 1. Aim: Converting glucose to a substance easily separated from fructose (ethanol) for the production of an enriched fructose syrup. 2. Transformation of raw materials: 2.1. Microbial changes: are predominant Micro-organisms use glucose and other nutrients for growth and increasing biomass. As the result of these activities, ethanol is produced. 2.2. Chemical physical changes: CO2 is produced and escape from the solution. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 50 3. Affective factors: Properties of inocula and conditions of the operation. Composition of media and micro-nutrients for growth and increasing biomass. Methods of fermentation: batch or continuous fermentation…also affect on the operation. 4. Technical parameters: 4.1. Fermentation using mutant Saccharomyces cerevisiea ATCC 36859: Method: Batch fermentation, t o = 33 o C Initial concentration of inoculum is 0.05g (dried weight) of biomass per 100ml of medium. In 27 hours 95% of glucose is consumed yielding 89.2% of the theoretical value of ethanol. The long fermentation time is caused by a low inoculum concentration and relative slow growth rate of mutant. When initial concentration of inoculum is increased from 0.05g to 0.14g (dried weight) of biomass per 100ml of medium, glucose is eliminated from the broth in 14.5 hours yielding 1.7% (w/v) of ethanol. In both cases, fructose concentration remains constant. 4.2. Fermentation using immobilized mutant Saccharomyces cerevisiea ATCC 36859: Method: Continuous fermentation, 33 0 C The beads contained 47 g biomass per liter of alginate material. At a dilution rate of 0.106 h -1 , the glucose concentration was reduced to 0.10 from 4.55% (w/v) producing ethanol in a concentration of 2.67% (w/v). The ethanol concentration was higher than it was theoretically possible to produce from the glucose used because some fructose was also consumed, reducing its concentration to 13.27% (w/v) from 14.44% (w/v). The ethanol yield, when the total amount of carbohydrate consumed was used as the basis for the calculation is 89% of the theoretical value. At this dilution rate, the carbohydrate content of the product was 99.25% fructose and only 0.75% glucose. When the dilution rate was increased to 0.254 h -1 the fructose concentration approached its inlet value. At this dilution rate, the product contains 96% of the total sugar as fructose and 4% as glucose. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 51 Table 14: The results show that even at the highest dilution rate (0.625 h -1 ), the product contained 93% of the total sugar as fructose and only 7% as glucose. Comparing this carbohydrate composition with that in the feed (77.2% fructose and 22.8% glucose), it can be concluded that a substantial increase in the fructose/glucose ratio can be obtained from the Jerusalem artichoke juice applying this technology. Therefore, the sugar mixtures produced from these treated juices would contain much less glucose than those which would be obtained from the untreated ones. FIG 24. Fermentation equipment. With an increase in the dilution rate and the glucose and total carbohydrate concentrations in the feed, increasing amounts of glucose were passing unconverted through the reactor. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 52 In batch experiments practically no fructose was consumed because the glucose concentration was low only at the end of the experiment when it was stopped. In addition, the biomass concentration that were used were low, resulting in a relatively low glucose rate and an even lower fructose rate which was not significant enough to be observed in batch experiments. To increase the economic viability of the process it is necessary to increase the glucose conversion rate and the outlet concentration of ethanol which is a valuable co-product in this process. To attain these objectives, the cell concentration in the beads was increased to 102 g/l (approximate two times higher than the previous beads). Jerusalem artichoke juice (supplemented with glucose) which contained 15.7% (w/v) glucose and 11.9% (w/v) fructose was used as the feed in this process. The experiments with the higher bead cell concentration exhibited the same type of relationship between the glucose/fructose consumption ratios. Table 15: FIG 25. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 53 This last test showed that Jerusalem artichoke juice supplemented only with glucose can be used for the production of a product containing fructose and a relatively high concentration of ethanol in a continuous process using S. cerevisiae ATCC 36859. XI. Activated charcoal treatment: 1. Aim: Removing colour, smell reagents and contaminants that have low molecular weight. 2. Transformation of raw materials: 2.1. Physical changes: The mass of the materials decreases. 2.2. Chemical physical changes: Adsorption contaminants that have low molecular weight, colour, smell reagents on surface and inside of activated porous charcoal. 2.3. Biological: Some of micro-organisms decrease due to their adsorption on activated charcoal surface. 3. Affecting factors: Physical characteristics of activated charcoal: - Holes density - Size of holes - Structure of activated charcoal Residence time of solution throught activated charcoal column. Chemical physical characteristics of impurities which need to be removed. 4. Technical parameters:  A bed of granular carbon consisting of Pitt.Chem.CPG granular 44x40 mesh  0.5 – 2 bed volumes per hour  T = 38 – 60oC FIG 26. Activated charcoal PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 54 XII. Concentration: 1. Aim: - Preservation: Increasing the content of fructose in the solution, means that osmotic pressure will incease and storage period will be longer. - Perfection: Help the product more acceptable in trade market due to the solid content requirement. 2. Transformation of raw materials: 2.1. Physical changes: The mass of materials decreases due to evaporation The viscosity of materials encreases 2.2. Physical chemical changes: Content of soluble agents increases Evaporation of water and agents that have a lower boil temperature than water (ethanol…) 2.3. Microbiological changes: Microbes are inhibited by osmotic pressure. 3. Affecting factors: o Time requirement for concentration step lasts long, the solid content of solution increases. However, the longer concentration time, the larger cost it is. o Temperature and pressure: Temperature is high, pressure is low, the solid content will increase, however the organoleptic of product will be degraded. o Characteristics of the materials and solid content requirement also effect on the process. 4. Technical parameters:  Equipment: Vacuum concentration  Temperature: 40oC – 60oC  Final solid content: up to 70% - 80% (w/v) PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 55 FIG 27. Vacuum concentration equipment PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 56 Chapter 4: Product I. Physical chemical characteristics of Product: Table 16: Table 17: Table 18: PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 57 II. Microbiological characteristics: III. Organoleptic characteristics: Color Colorless or yellowish ， light transparent and viscous liquid Smell Smell of fructose Flavor Sweet taste, no peculiar smell Total bacteria ≤1500 cfu/ml Pathogens (salmonella) Negative Mesophilic Bacteria 200 cfu/10g max Yeast 10 cfu/10g max Mold 10 cfu/10g max PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE STUDENTS: NHAN-LAN-HUY 58 Chapter 5: High-fructose syrup application Sucrose is a disaccharide comprising equimolar ratios of dextrose and fructose, covalently bonded together. In several major product applications of sucrose, the disaccharide is hydrolyzed to monomeric subunits through a process called inversion. Inversion is catalyzed either by the low pH of the product, as in carbonated beverages, or through the action of yeast enzymes, as in baked goods. Because the carbohydrate profile of HFS closely resembles that of an invert sugar, both of these applications became logical targets for HFS when fructose-containing syrups were first introduced. The major applications for HFS are now carbonated beverages and raised bakery products. Bakers found that HFS gave them finished products nearly identical to those sweetened with sucrose, was more economical to use, and was easier to handle than was sucrose. Because HFS can be obtained at higher solids levels than liquid sucrose, less space is needed to store an equivalent amount of sweetener solids. HFS is also extremely resistant to microbial spoilage because of the high solids level and the higher osmotic pressure generated by the monosaccharides. In the processing plants where the possibility of airborn yeast exists, this stability was readily welcomed. Table 19: The carbonated beverage industry is the largest user of HFS-42 and -55. The 42% fructose product is used primarily in non-cola beverages, often acidified with an organic acid system that is easier to sweeten. Many cola systems, however, use phosphoric acid, which requires the higher sweetness of HFS-55 to give the correct flavor balance; alternatively, an increased amount of HFS-42 may also be used. The carbonated beverage industry was a major contributor to the FIG 28. PRODUCTION OF FRUCTOSE SYRUP FROM JERUSALEM ARTICHOKE SUPERVISOR: VAN VIET MAN LE 59 improvement in quality of HFS products that has taken place in the last 10 years. The National Soft Drink Association developed stringent guidelines, complete with approved testing methodology for color, taste, odor, ash, fructose, other carbohydrate amounts and microbial standards. These guidelines are universally employed and have served to continually improve the quality of HFS. As a result, >90% of energy-containing carbonated beverages produced in the United States are sweetened with HFS. Flavor enhancement a natural compatibility with fruit flavors are two reasons the fruit-canning industry has become the third major user of HFS, behind carbonated beverages and baking industries. HFS is frequently blended with liquid sugar and corn syrups to get the right balance of sweetness and fruit flavor. HFS-42 is primarily used, again because of its economy and compatibility with organic acid systems. HFS is used extensively as a sweetener in dairy products like yogurt, chocolate milk and ice- cream. Quality and economy are once more the primary reasons, in addition to improve flavor perception and rapid fermentability in yogurt, and mouthfeel and viscosity in ice-cream and chocolate milk. The makers of jams, jellies and preserves are also major user of HFS. High- solids systems can be formulated by using HFS and corn syrups without the storage problem of crystallization common to sucrose and dextrose. HFS again enhances fruit flavors and stabilizes the color in these products throughout their storage life. FIG 29. References [1] Barrelt L. Scallet, Process of purifying high D.E.-very sweet syrups, Patent number 3383245, 1968 [2] C.H.KIM and S.K.RHEE, Fructose production from Jerusalem artichoke by inulinase immobilized on chitin, Biotechnology Letters Vol 11 No 3 201-206 (1989). [3] D.W. Korean and Z.Duvnjak, Continuous production of fructose syrup and ethanol from hydrolyzed Jerusalem artichoke, Journal of Industrial Microbiology 7 (1991) p. 131-136. [4] Ernst Hoehn, Production of high fructose syrup from inulin involving ultrafiltration, Patent number 406178, 1983. [5] L. Mark Hanover and S. White, Manufacturing, composition, and applications of fructose, Am. J. Clinical Nutrition 1993:58(suppl): 724S-732S [6] N. Kosaric, The Jerusalem Artichoke as an Agricultural Crop, Biomass 5 (1984) p. 1-36. [7] S.Schorr-Galindo, Fructose syrups and ethanol production by selective fermentation of inulin, Current microbiology Vol.30 (1995) p.325-330. [8] Sarote Sirisaneeyakul, Production of fructose from inulin using mixed inulinases from Aspergilus niger and Candida guilliermondii, World Journal Microbiol Biotechnol 23 (2007) p. 543-552. [9] Stephen Vuilleumier, Worldwide production of high-fructose syrup and crystalline fructose, Am. J. Clinical Nutrition 1993:58(suppl): 733S-736S [10] Wei Wenling, Continuous preparation of fructose syrups from Jerusalem artichoke tuber using immobilized intracellular inulinases from Kluyveromyces sp. Y-85, Process Biochemistry 34 (1999) p. 643-646. [11] Wei Lingyun, Studies on the extracting technical conditions of inulin from Jerusalem artichoke tubers, Journal of Food Engineering 79 (2007) p. 1087-1093. [12] Z. Duvnjak and D. W. Korean, Production of fructose syrup by selective removal of glucose from hydrolyzed Jerusalem artichoke.