The thesis was presented on the 29 March, 2006
Approved by NCAA on the 29 June, 2006
– 0.85 Mb / in romanian
6.15 Mb /
membrane, coloring matter, inverse osmosis, ultrafiltration, anthocyanins
The goal of the paper is to elaborate a new technology of anthocyanins coloring matter manufacturing using new procedures based on membranes, semipermeable.
The process of obtaining raw materials (the anthocyanins extract) was performed following the formula below:
- weet husks of grapes→H2O solvent (Duty of water 1:1) (Initial t = 20ºC)→Yeast dredge (1.5% C = 65 mln/ml) Fermentation with periodical mixing
- The process getting the initial coloring matter of anthocyanins through the proposed method diminishes considerably the concentration of the ballast substances which are directly proportional with the osmotic pressure of the solution which in turn increases the efficiency of the bar-membrane process of concentration.
- To purify the coloring matter from the ballast substances and other polluting elements we used a new method based on ultra-filtration membranes. For research we used the following ultra-filtration membrane: УАМ-300 (tip БТУ 0,5/2 type, tubular, element’s surface 0.5 m2, working pressure not exceeding 0.7 Mpa, the preferred pH – 4…8), which in turn allows us to carry out the process at a high productivity rate 70…40 dm3/m2 h and with a sufficient retention of the biopolymers (polysaccharides with 95…96%, proteins with 66.8 …92.1%). The optimal processing parameters are: the pressure difference 0,15 … 0,25 MPa, the tangential flow speed 2…3 m/s, the filtration cycle – 22 h, the regeneration cycle – 2 h. The process of anthocyanins purification based on the ultrafiltration membranes, though it reaches the goal set has a specific disadvantage, membrane absorption of polluting elements and decrease of work capacity.
- To eliminate this shortcoming and to perform the process in semiflow we elaborated the technological procedures of regeneration of the semipermeable membranes and the optimal parameters. The membrane regeneration technology:
- washing with water (t 10…20°C) for 30 min;
- washing with a special solution (over-measure of NaOH till pH 8 and 150 g of detergent that doesn’t make foam to 10 dal of solution) at the temperature 20…30°C, pressure 0.1 …0.2 MPa, tangential flow of 4…5 m/s, for 120 min;
- rinse with water (t 10…20°C) for 30 min at the pressure 0.1 – 0.7 MPa.
One of the stages in the technology of producing the coloring matter of anthocyanins is the process of solution concentration. To concentrate the anthocyanins coloring matter, a new method was used based on inverse osmoses of the membranes. In the research two types of inverse osmoses membranes were used: МГА-95, МГА-100.
The study of the inverse osmoses process allows us to state that to concentrate the coloring matter it is rational to use МГА-95 membranes of the type ЭРO with a selectivity (after NaCl) of 95%. The process of concentration should be performed in the semi-period regime. The initial coloring matter volume for one cycle of concentration should be sufficient so that the concentration of 10…12 times (depending on anthocyanins concentration in the initial coloring matter) to be performed during 6 h. The pressure at the surface of the membrane is sufficient to be from P 2-4 MPa. The coloring matter concentrate must be evacuated from the installation once it has reached the necessary concentration level (20…25 gr/dm3). The maximal possible concentration of anthocyans on osmos-invers membranes is 20-25 g/dm3 indifferently of basical anthocyans concentration in first coloring matter. Simultaneously, the concentrate from the installation should be substituted with an initial coloring matter. The obtained concentrate should be cooled off for the tartaric acid crystals sedimentation, acid which appeared as a result of coloring matter concentration 7 – 12 times.
There were elaborated the technologies of anthocyanins coloring matter production based on semipermeable membranes. For implementation in the production process, a technological instruction has been elaborated.