| Sucrose is high purity carbohydrates and important energy sweeteners in food industry, and is the world's largest production in sugar industry. Sucrose is non-reducing sugar linked by the glycosidic bond ofα-D-glucose C1 andβ-D-fructose C2, containing three primary alcohol hydroxyl and five secondary alcohol hydroxyl groups. Various derivatives (i.e: sucrose fatty acid ester, sucralose, sucrose polyether and polyurethane resin) can be obtained through the chemical reaction of the hydroxyl group with the etherification, esterification, substitution, decomposition and condensation polymerization. Sucrose could be exploited as the surface active agent, detergent, plastic, medicine, new additives and various products by physical, chemical, and biological way. Thus, exploring new territory of high value added products of sucrose has the vital significance.In this paper, the new functional additives STOC, prepared from acidified sucrose by the thermochemical method, were comprehensive researched, including the preparation process and characteristics. The main contents and results were as follows:The STOC was prepared by different dry and wet process, and the principal component analysis and structural equation model were used to statistically analyze every index. These results showed traditional and vacuum dry process were superior to microwave dry process, and high pressure reactor process was superior to pulse electric field process in yield, and the yield of dry and wet process increased within the 100-160 oC with a subsequent decrease. However, the resinification and carbonation reaction occurred under more than 160 oC in high pressure reactor process. The principal component analysis and structural equation model showed the vacuum dry process was more suitable for the preparation of STOC. The absorption value at 420nm significantly positive correlated with reducing sugar and the absorption value at 294nm, and significantly negative correlated with pH value. The absorption value at 420nm significantly negative correlated with total sugar content, and significantly positive correlated with pH value. Absorbance and total sugar content were the more representatives of its characteristics.Using the the heating temperature, holding time, the citric acid concentration and ammonia water amount and concentration as the index, the yield and DPPH scavenging ability of STOC was studied and optimized. The single factor experiments showed the heating temperature, holding time and citric acid concentration were key factors.The Box-Behnken design (BBD) was used to optimize the above critical factors, the optimal technological parameters were obtained as follows: the heating temperature 162 oC, the holding time 0.95h, the citric acid concentration 0.94%. The experimental values (83.91±1.82%) of yield was coincidental with those predicted. The heating temperature 167 oC, the holding time 1.05h, the citric acid concentration 1.04%, the DPPH scavenging ability was 88.61±2.13%.The pH value stability, moisture absorption and retentation, heat stability and DPPH scavenging ability of STOC were studied to analyze the physicochemical characteristics. The results showed the stability of STOC was poor in alkaline environment, and better in neutral and acidic conditions. The biggest moisture absorption was 81.78% under temperature 30 oC, relative humidity 95%, and the biggest moisture retentation was 9.71% under relative humidity 30%. DSC analysis illustrated that the acidified sucrose thermal denaturation curve had two narrow peak, contained two substances; however, the STOC thermal denaturation curve had a bigger absorption peaks, including plenty of similar substances having the thermal denaturation temperature at 144.53 oC. The DPPH scavenging ability of STOC prepared at 100 oC was very lower due to the lower reaction rate and content of STOC. But, the DPPH scavenging ability of STOC prepared at the optimum process was 95.96% when the concentration was 40mg/mL, and the IC50 was 2.81 mg/mL. With the reaction temperature increasing, the color rate, red and yellow index, and turbidity were on the rise, and the optical rotations to drop. The color rate was 15000 EBC, red index was 8.158, yellow index was 9.116, the optical rotation was 0.717±0.120, and turbidity was 2.180±0.160 IU under the optimal technological parameters.The STOC ingredients were separated by the gel column and active-carbon adsorption column, using HPLC and ion chromatography to monitor the carbohydrate content and molecular weight of STOC or separation. The results showed active-carbon adsorption column was superior to Sephadex G-100 and Bio-gel P-2 column in separation of STOC, but the recovery and yield of STOC was low. HPLC and ion charmatography analysis showed STOC contained monosaccharide (glucose and fructose), sucrose, 1-kestose and more polymerization degree oligosaccharides.The hydrolysis and GC-MS were used to analyze the STOC and the ingredients of active-carbon adsorption column separation. Results showed 1,6-dehydration-α-D-pyranoglucose, 1,6-dehydration-β-D-furanglucose and 1,6-dehydration-β-D-pyrano- glucose were the main ingredinets.The methylation analysis indicated that most of fructosyl were incorporated into C1 and C6, and a few part incorporated into C2, C3 and C4 to form branched structure. The infrared spectrum showed the STOC contained functional group characteristics of the sugar. The pyrolysis products of STOC prepared from different temperature was furan, ketones, aldehyde, furan ketone, pyrazole, and anhydride. Acidified sucrose contained 12%-15% water, and D-glucose and fructose was produced after the short-term hydrolysis reaction. And with the heating and acid effect, the reaction of dehydration, thermal degradation and the sugar complex reaction were happened, the fructosyl cation and glucosyl anion were formed by the scission of glycosidic bond. And then the fructosyl cation reacted with the hydroxyl to form oligosaccharide, linking with one location hydroxyl of fructose formed 1-ketose, six location hydroxyl of fructose formed 6-ketose, 6′location hydroxyl of glucose formed neoketose. Thus, reaction could occur with sucrose, glucose (also formed by the scission of sucrose), and to form more molecular weight oligosaccharides by polymerization.Antibacterial ability and antibiotics titer evaluation of STOC were appreciated by microbiological assay of antibiotics. Moreover, it could conclude that the orders of the antibacterial ability were as follows: Staphylococcus aureus > Escherichia coli > Bacillus subtilis > Micrococcus luteus, and no antibacterial effect to Aspergillus niger and Rhizopus nigricans. The effect of STOC on total anaerobes, beneficial bacterium (bifidobacterium and lactobacillus), major flora (bacteroides) and pathogen (enterobacter) of human intestinal was evaluated in batch cluture using STOC or glucose as the only carbon source. The 24 h in vitro fermentation experiments revealed that STOC affected the growth of gut bacteria during mixed culture growth and increased the absorbance of culture. The products prepared from 140-160 oC were more suitable for intestinal microbial growth; Lactobacilli and bifidobacteria were increased in the anaerobic bacteria enumerated by the STOC, and bacillus and enterobacter were certainly inhibited.
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