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In last years,consumers pay more attention to natural and body-friendly pigments. There is a great tendency to promote and popularize natural dyes instead of synthetics. But instability of these natural pigments has many negative impacts on application. However,melanoidins,high molecular weight brown nitrogenous polymers formed at the end of the Maillard reaction,are increasingly studied by scholars ascribe to its enormous biological activity. They are normally formed during heat processing of foods. This brown-colored compounds may be a natural pigment due to its desirable dark brown and biological activity.what’s more,its ability is superior to other natural pigments. On the other hand,this compounds’ isolation and purification are the key step for further use and biological maintenance in various kinds of industries. However,the selection of methods is mainly dependent on their structure. It is necessary to seek out some effective modification or advanced technologies to update and even take place of the traditional methods, among which a large quantity of ways about extraction is time-consuming. Hence,this review summarizes extraction methods of melanoidins,exploring the recent literature regarding the feasibility of emerging extraction methods and as a new potential natural pigment.

Activated-hydrochar (AHC) derived from sugarcane bagasse was synthesized by hydrothermal carbonization (HTC) using phosphoric acid and sodium hydroxide (NaOH) as activators. The properties of AHC were systematically characterized by elemental analysis, BET, SEM, FTIR, XPS and zeta potential, and applied to evaluate the adsorption ability of methylene blue (MB) by batch adsorption tests. The MB adsorption isotherm and kinetics of AHC were well described by the Langmuir model and pseudo-second-order kinetic model. Characteristic analysis suggested electrostatic attraction, hydrogen bonding and π-π interactions were the main contributors to MB adsorption. Analysis of mass transfer mechanisms demonstrated the adsorption process towards MB by AHC involved intra-particle diffusion to some extent. Thermodynamic studies indicated MB adsorption was an endothermic, spontaneous process associated with a disorder increase at the solid-liquid interface. The maximum adsorption capacity of AHC for MB was 357.14 mg g

In this study, a novel polyethyleneimine (PEI) modified MOF-derived carbon adsorbent (PEI@MDC) was proposed, which exhibited significant adsorption capacity for Congo Red (CR) in aqueous solutions. FT-IR and XPS results showed that PEI was successfully grafted onto MDC, increasing the content of amine groups on the surface of MDC. The adsorption process conformed to the Langmuir isotherm adsorption model and pseudo-second-order kinetic equation, indicating that the adsorption of CR on PEI@MDC was covered by a single layer, and the adsorption process was controlled by chemical processes. According to the Langmuir model, the maximum adsorption capacity at 30 °C was 1723.86 mg g

We present a simple, low-cost method for producing activated-carbon materials from sugarcane tips (ST) via two-step pre-carbonization and KOH activation treatment. After optimizing the amount of KOH, the resulting ST-derived activated carbon prepared with a KOH to PC-ST mass ratio of 2 (ACST-2) contained 17.04 wt% oxygen and had a large surface area of 1206.85 m2 g−1, which could be attributed to the large number of micropores in ACST-2. In a three-electrode system, the ACST-2 electrode exhibited a high specific capacitance of 259 F g−1 at 0.5 A g−1 and good rate capability with 82.66% retention from 0.5 to 10 A g−1. In addition, it displayed a high capacitance retention of 89.6% after 5000 cycles at a current density of 3 A g−1, demonstrating excellent cycling stability. Furthermore, the ACST-2//ACST-2 symmetric supercapacitor could realize a high specific energy density of 7.93 W h kg−1 at a specific power density of 100 W kg−1 in 6 M KOH electrolyte. These results demonstrate that sugarcane tips, which are inexpensive and easily accessible agricultural waste, can be used to create a novel biomass precursor for the production of low-cost activated carbon materials for high-performance supercapacitors.

The effect of Maillard reaction browning factors on the color enhancement of membrane clarification non-centrifugal cane sugar (M-NCS) in storage was explored. During storage, the color of M-NCS gradually browned and blackened. pH, the contents of glucose, fructose, protein, total amino acids and 5-hydroxymethylfurfural (5-HMF) decreased significantly. Meanwhile, the moisture content, relative percentages of volatile Maillard reaction products (MRPs) and the content of 3-deoxyglucosone (3-DG) increased during storage. The sucrose content remained stable. Correlation analysis shows all browning factors were significantly correlated with color. Multivariate data analysis results demonstrated that the compound effects of volatile MRPs, 3-DG, pH, glucose and total amino acids led to the color change of stored M-NCS. The order of effect on the color change of stored M-NCS was volatile MRPs > 3-DG > pH > glucose > total amino acids.

The development of volatile compounds and their precursors during the dehydration process of membrane-clarified sugarcane juice to non-centrifugal sugar (NCS) was investigated. Head-space solid phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) coupled with chemometrics was employed to assess the differences at the various stages of the dehydration process. A total of 111 volatile compounds were identified, among which 57 were endogenous compounds from sugarcane juice and displayed an attenuated abundance in the first 30 min. Typical oxygen and nitrogen heterocyclic compounds, including furans and pyrazines, and aldehydes derived were found to be the main volatiles contributing to the formation of NCS characteristic aroma, with phenols, alcohols, esters, acids, and sulfur compounds as supplementary odor. Free amino acids and reducing sugars were identified as important precursors for the aroma development process. The low temperature (90–108 °C) and micro vacuum condition (−0.03 MPa) approach used in this study could be an alternative option for the manufacture of NCS.

Dextranase from Chaetomium gracile is generally considered safe for use in the sugarcane industry. Herein, a truncated and codon-optimised α-dextranase gene from C. gracile was successfully cloned and expressed in Saccharomyces cerevisiae for the first time. The optimum conditions of fermentation was achieved when the maximum dextranase activity reached to 58.45 U/mL after 48 h in shake flasks. The optimal pH and temperature were 5.5 and 60 °C, respectively. The recombinant dextranase remained stable between pH 4 and 6 and temperature between 55 and 60 °C. The findings in the present study could facilitate large-scale production of food-grade recombinant dextranase for use in the sugar industry.

The effect of pretreatment of sugarcane juice and juice composition on the performance of a ceramic membrane with pore size of 20 nm has been studied. Pretreatment options assessed included heating juice (60, 75 and 90 °C) with and without sedimentation at specified pHs (7.2, 7.5 and 7.8) and using evaporator supply juice (ESJ). The average permeate flux at 75 °C and pH 7.8 for limed juice, and partially clarified juice, and ESJ were 278 L/m2h, 248 L/m2h and 160 L/m2h in that order. It was shown that with ESJ, where the juice is boiled, there are higher proportions of crystalline and microcrystalline phases, and other impurities which reduces the efficiency of the membrane filtration process as the cake resistance (1.17 × 1012/m) is 1.7 times higher than of the partially clarified juice. With respect to the juice quality, the results of the permeate derived from the partially clarified juice at 75 °C, show that the lowest pH value of 7.2 gave the largest impurity reduction, though liming at pH 7.5 would be the preferred treatment for industrial application because of pH drop during processing. The fouling mechanism for the partially clarified juice was shown to be the combined cake filtration-complete blocking model.

Purpose d-psicose-3-epimerase (DPEase) catalyses the isomerisation of d-fructose to d-psicose, a rare sugar in nature with unique nutritional and biological functions. An effective industrial-scale method is needed for d-psicose production. Herein, the expression of a neutral and a slightly acidic pH DPEase in Bacillus subtilis was evaluated. Methods Two DPEase genes from Clostridium bolteae and Dorea sp. were separately expressed in B. subtilis via plasmid pSTOP1622, and an extra P43 promoter was employed to the expression cassette. The fermentation conditions of the engineered B. subtilis strains were also optimised, to facilitate both cell growth and enzyme production. Result The introduction of P43 promoter to the two DPEase genes increased enzyme production by about 20%. Optimisation of fermentation conditions increased DPEase production to 21.90 U/g at 55 °C and 24.01 U/g at 70 °C in B. subtilis expressing C. bolteae or Dorea sp. DPEase, equating to a 94.67% and 369.94% increase, respectively, relative to controls. Conclusion Enhanced DPEase production was achieved in B. subtilis expressing C. bolteae or Dorea sp. DPEase genes.

The development of post-haze in concentrated sugarcane juice (CSJ) during storage is a common problem which appears sporadically and usually without obvious cause. In the current study, sediment components in hazed CSJ were investigated. Thermogravimetric analysis demonstrated that the sediment was primarily composed of organic materials. Fourier transform infrared spectra showed that polysaccharides, proteins, esters, colloids, and polyphenols were the primary components of the sediment. Scanning electron micrographs and energy-diffusive X-ray spectra also indicated that the sediment was mainly composed of organic materials. A small amount of inorganic elements, such as Na, Mg, Al, Si, and S, were also found in the sediment. Moreover, CaCO3 crystal was unexpectedly detected in the sediment. This study is the first to investigate the components of sediment in hazed CSJ.

A ceramic membrane is applied to improve the clarification of sugarcane juice and reduce or eliminate the usage of chemicals in sugar industry. Although membrane fouling is unavoidable, fouling can be solved by understanding its mechanism and developing an effective approach to regenerate membranes. Mathematical model prediction, scanning electron microscopy (SEM), and atomic force microscopy (AFM) during membrane fouling indicated that the dominant fouling during ultrafiltration of limed raw sugarcane juice was caused by cake formation on the membrane surface. Energy-dispersive X-ray spectrometry (EDX) and Fourier-transform infrared spectrometry (FTIR) revealed that polysaccharides, proteins, aliphatics, sucrose, phenols, phosphorus, silicon, and few metal elements, such as calcium, magnesium, aluminum, potassium, and sodium, were the compositions of foulants primarily responsible for fouling. An effective membrane cleaning method was proposed on the basis of these findings. The fouled membrane was successively cleaned with tap water, 1.0% NaOH and 0.5% NaClO mixture, and 0.5% HNO3 solution. The flux recovery ratio was higher than 96.6%, and this value indicated the high repeatability, efficiency, and feasibility of this cleaning method. This method has also helped identify the compositions of foulants on membranes and vice versa.

Concentrated sugarcane juice (CSJ) is considered as one of the healthy sugar products, and so a potential feedstock in beverage formulations and soft drinks. However, irreversible aggregates, which are unattractive to the customer, are found with CSJ derived from the membrane filtration during storage. This study examined the formation of aggregates during the concentration of sugarcane juice to CSJ, and during CSJ storage. The concentration process for the formation of the aggregates goes by 3 stages, with polysaccharides interacting with phenolics and then proteins to form complexes which bind non-covalently to SiO2. For stored CSJ, inorganic compounds (mainly SiO2) were the main constituents in aggregates accounting for 43.14 % (w/w), followed by proteins, phenolics, polysaccharides, organic acids, and lipids. The results obtained with stored CSJ/NCS indicate that the proteins interact with phenolics and polysaccharides to form the flocs which then co-precipitate with SiO2 and calcium salts. The polishing of sugarcane juice with a multifunctional adsorbent in combination with the membrane filtration process could be a prospective approach solve the haze/aggregation problems associated with the CSJ, and further promotes their application in beverage formulations.

The differences in the source and structure of xylans make them have various biological activities. However, due to their inherent structural limitations, the various biological activities of xylans are far lower than those of commercial drugs. Currently, several types of molecular modification methods have been developed to address these limitations, and many derivatives with specific biological activity have been obtained. Further research on structural characteristics, structure-activity relationship and mechanism of action is of great significance for the development of xylan derivatives. Therefore, the major molecular modification methods of xylans are introduced in this paper, and the primary structure and conformation characteristics of xylans and their derivatives are summarized. In addition, the biological activity and structure-activity relationship of the modified xylans are also discussed.

Dextran causes negative impact on the normal production of sugar industry. Traditional removal methods have many disadvantages. 6-alpha-d-glucan-6-glucanohydrolase (EC 3.2.1.11) from Chaetomium gracile without food safety concern could remove dextran, but it has low level of enzyme production. The present study aimed to improve α-dextranase activity to meet industry demand. Consequently, α-dextranase activity reached 242.8 U/mL when fermentation condition was 29 °C, pH 6.0 and 220 rpm. Meanwhile, ten glass beads were added to fermentation medium when fermentation time was 12 h, which improved enzyme activity by 135.5% with the highest activity. Purified α-dextranase exhibited excellent thermal stability and surfactants tolerance. α-Dextranase from C. gracile could remove dextran by 46.6% in mixed sugarcane juice and 14.1% in clarified sugarcane juice. It had similar dextran removal efficiency with commercial enzymes. These evaluations showed that α-dextranase had great potential in removing dextran in sugar industry.

A ceramic ultrafiltration membrane is applied to treat sugarcane juice, to improve the quality of the clarified juice, and to reduce or eliminate the usage of chemicals in the sugar industry. Although membrane fouling is unavoidable, fouling can be solved by understanding its mechanism to develop optimal operating and cleaning strategies. In this study, four combined fouling models, namely cake–narrowing–blocking, cake–narrowing, cake–blocking, and narrowing–blocking, were developed and employed to elucidate the ceramic membrane (0.05 μm) fouling mechanisms during the ultrafiltration of limed sugarcane juice. Results showed that the fitting of the combined models was better than that of any of the individual models. Ceramic membrane fouling during sugarcane juice ultrafiltration was complex possibly because of the involvement of several fouling mechanisms instead of one model. The dominant fouling mechanism was cake layer formation followed by pore constriction, and the rate of existence of pore blocking was the lowest among the combinations.

Retentate is a by-product of the membrane clarification of sugarcane juice process and contains high sucrose concentration which is not recovered during sugar manufacturing. The lack of cost-effective treatment of retentate produced by membrane clarification is one of the main issues that hinder adoption of membrane technology in the sugar industry. The present work evaluates retentate composition and uses the information to explore effective approaches for retentate utilization. Compositional analysis revealed that the insoluble components was 6.25% of the retentate in which 48% was organics, and 52% was inorganics. Sucrose (14.9%) was the dominant component followed by reducing sugars (0.62%). Significant amounts polysaccharides (2%) and proteins (0.5%) were present in the retentate, far higher than those present in mixed juice. Lipophilic compounds (e.g., fatty acids, octacosanol, stigmasterol and β-sitosterol) were accumulated in the retentate (3.56% based on the dry substance), while the phenolic compounds content (equivalent to 1.1 mg gallic acid·g−1) was similar to that in mixed juice. Based on the retentate composition, it is proposed that a multifaceted approach can be used to harness various products from sugarcane retentate concentrate. As the carbohydrate component is the highest component in the retentate, two approaches were evaluated to add value, namely sugar recovery via the carbonation process and production of oleaginous yeast biomass from the retentate by a R. glutinis strain. Carbonation clarification was effective to clarify retentate, and it was estimated that 71.2% of sucrose can be recovered using typical sugar manufacturing processes. Biolipid derived has the potential for biodiesel production and the biomass residue had the potential to be used as a valuable feed supplement. A preliminary comparative economic analysis was conducted with the two approaches considering the value of the final products (i.e., sugar and biolipid/biodiesel) and their operating costs.

The fungus Chaetomium gracile is used for production of dextranase and removal of dextran during sugar manufacturing process, however, the productivity of dextranase is low. In this study, we investigated the influence of carbon source on dextranase production using dextrans of different sizes. Culturing C. gracile in medium containing crude dextran and use of high molecular weight of dextrans resulted in the higher yield of dextranase production (80.5 ± 4.0 U ml−1). Cells incubated in medium containing glucose as sole carbon source exhibited a high growth rate but did not produce dextranase. Based on these findings, fed-batch and two-step fermentation strategies were employed to further increase the yield of dextranase with production of 159.5 and 187.0 U ml−1, respectively.

In this study, the effects of ultrasonic parameters on the synthesis of sucrose laurate were investigated under four frequencies (20, 33, 53, and 80 kHz). Results indicated that low ultrasonic frequency increases sucrose monolaurate yield, whereas high ultrasonic frequency increases sucrose dilaurate yield. As the sound intensity increases from 0.55 to 1.04 W cm−2, the yield of sucrose laurate also increases, whereas the reaction time decreases. The yield of sucrose laurate decreased, and the reaction time prolonged with the decreasing pulse width. Both the initial production rate of sucrose monolaurate and the yield of sucrose dilaurate increased with the increasing temperature from 60 to 90 °C. However, further increase in the reaction temperature did not increase the yield of sucrose monolaurate but significantly reduced the reaction time. Sucrose laurate synthesized under ultrasonic frequency consisted of sucrose monolaurate, dilaurate, and polylaurate.

A field demonstration on the ultrafiltration of sugarcane juice for raw sugar production was conducted in a raw sugar mill in Guangxi Province, China. Heated limed sugarcane juice was processed using 0.05 μm ceramic membranes in a pilot plant with a design capacity of 5.5 m3/h. Results indicated that the ceramic membrane modules were satisfactory for sugarcane juice clarification, which yielded 119.13–142.43 L/(m2 h) of average flux under the volumetric concentration factor of 10–12 and produced clarified juice of superior quality with more than 1.2 unit rise in purity, 99.96 % reduction in turbidity, and 10.42 % removal of color. The membrane cleaning period was 10–25 h. Moreover, a high-quality product with high Pol, low color, and low ash content was obtained when the permeate juice was concentrated and crystallized to form raw sugar. However, further studies are necessary to investigate the methods of processing retentate for the recovery of sucrose and handling of wastewater generated during membrane cleaning, as well as the service life of the membrane.

The performance of a ceramic microfiltration membrane with 0.5 μm pore size in clarifying carbonated remelt syrup that was filtered by plate-and-frame filter press was investigated under different operating conditions. In total reflux experiments, using 0.5 μm ceramic membranes for treating carbonated, filtered remelt syrup at 80 °C produced steady-state fluxes of 328.4 and 293.1 L/(m2 h) at a cross-flow velocity of 5 m/s, and transmembrane pressures (TMPs) of 3.0 and 2.5 bar, respectively. Decreasing the temperature to 75 °C yielded a corresponding flux of 271.8 L/(m2 h) at a TMP of 3.0 bar. In concentration experiments, when treating 750 L of syrup, 96.7, 76.9 and 72.0 L/(m2 h) of average fluxes were obtained under three operating conditions mentioned above. All conditions produced high-quality filtered syrup. Research on membrane resistances indicated that TMP significantly affected irreversible cake resistance. The increase in cross-flow velocity decreased cake resistance but insignificantly affected pore blocking resistance. All component resistances were decreased with increasing temperature. Membrane fouling dynamics could be represented through a pseudo-first-order rate equation. Fluxes of fouled membranes were recovered by successive cleaning with de-ionized water, a 1% NaOH + 0.5% NaOCl mixed solution, and a 0.5% HNO3 solution.