The Mathematic Model, Mechanism Analysis Of Low Methoxyl Pectin Gels And Pectin Production Based On The Aspen Plus Technology

A systematic study was made of the gelation of low methoxyl pectin (LMP) as the following aspects:the gel strength of different calcium ions, pH and pectin concentration were determined by Texture Analyzer, and the mathematical models were established for the gel strength under different factors. In order to analyze the mechanism of gels under different factors, the Rheometer was used to mensurate storage shear modulus (G') and loss shear modulus (G"). In addition, Aspen Plus was used to design the process of pectin factory production, material balance, equipment parameters simulation, and provide practical guidance for the production of apple pectin. The results show that:1?The mathematical model on gel strength of [Ca2+], applied the function of Doseresp which showed a similar to microbial growth curve. The mathematical model on the gel strength of pectin concentration was the BiDoseresp function.2?Because of without junction zone formation or it was not meet the amount of gels, gels was in a state of liquid-like when the [Ca2+] content was below 8.00 mg/g. With the increasing of [Ca2+], gel strength increased in the range of 16.00-40.00 mg/g. And when the [Ca2+] was in the range of 40.00-64.00 mg/g, gels could be more elastic and stable. However, even though gels could form in the range of 64.00-88.00 mg/g of [Ca2+], the surface of gels were rougher and rougher. Above 88.00 mg/g [Ca2+], pre-gelation could take place during or immediately after gel preparation that changed the gel structure.3?When pH was in the range of 3.10-5.00, in addition to hydrophobic interactions and hydrogen bonding interaction, Ca-bridges at subsequent free dissociated carboxyl groups were significantly strengthen the gel strength. Gel strengths were fluctuated in the vicinity of 22.00 g. With the increasing of pH beyond 5.00, hydrogen bonds between undissociated carboxyl groups gradually disappeared and hydrophobic interactions were so weak that the gel strength was about 8.22g. When the pH increased to 6.62, the strong electrostatic repulsion between pectin chains leaded to pectin gradually depolymerization.4?The BiDoseresp function implied that when increased the pectin concentration, because of the increase in cross-linking junctions between the pectin chains, gel strength were increased in the range of 6.00-25.00 g/L. If increased the sucrose content, gel strength would increase. It may be due to sucrose provided more hydroxyl groups to stabilize the structure of junction zones and promote hydrogen bonds to immobilize free water.5?Apple pectin production flow chart, equipment parameters, and energy consumption information were designed by Aspen Plus. According to the simulation results, the direct cost was calculated to show that the production per kg of pectin consumed 2.56 kg of ethanol,1.50 kg of citric acid, and 11.22 kg of steam.