JPS5925588B2 - Method for manufacturing pectin - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing pectin.

The juice lees produced in the process of producing fruit juices such as mandarin oranges and tomatoes has traditionally been dehydrated and dried and used as livestock feed or fuel, but the energy costs required for dehydration and drying are high;
Furthermore, since the squeezed lees contains pectin, it is not preferable from the standpoint of effective use of resources.

For this reason, in recent years, attempts have been made to concentrate and recover pectin contained in squeezed lees by membrane treatment using semipermeable membranes, but none of the conventional methods It was considered impossible to put this method into practical use because a pectin film quickly adhered to the membrane surface after the treatment started, significantly reducing the water permeation rate. The present invention has been made to solve the above problems, and its purpose is to provide a practical and economical method for producing pectin using a membrane treatment method that does not cause a significant decrease in water permeation rate over time. do.

The method for producing pectin according to the present invention involves feeding a pectin-containing acidic extract as a thin laminar flow into a narrow gap between two semipermeable membranes or a semipermeable membrane and a spacer, and then concentrating it. It is characterized in that it is obtained by adding a water-miscible organic solvent to the thus obtained concentrate to precipitate pectin.

0 As the semipermeable membrane used in the present invention, since the molecular weight of pectin is usually about tens of thousands to hundreds of thousands, an ultrafiltration membrane with a molecular weight cutoff of 1 to 1 million is suitable, and here Molecular weight is calculated by membrane-treating a 0.5% aqueous solution of polyethylene glycol at a pressure of 4 Kfl/cm2 and a temperature of 205°C, using the formula (1-(polyethylene glycol concentration in permeate/
When the exclusion rate defined as polyethylene glycol concentration in the feed solution)) x 100 is 90% or more, the average molecular weight of this polyethylene glycol is taken as the molecular weight cutoff of the semipermeable membrane.

Materials for such semipermeable membranes include cellulose acetate, nitrocellulose, crosslinked polyvinyl alcohol, saponified ethylene-vinyl acetate copolymer, polyamide, polyimide, polysulfone, and polyether, since the extract is usually acidic with hydrochloric acid. ! 5 Sulfone, polyvinyl chloride, etc. are suitable. Membrane treatment methods are already known in which a liquid to be treated is supplied to a narrow gap between two semipermeable membranes or between a semipermeable membrane and a spacer to form a thin laminar flow. The membrane module is called a so-called laminar flow type membrane module.

In the present invention, for example, a rod-shaped spacer is inserted and fixed into a tubular semipermeable membrane, and the gap distance between the membrane surface and the spacer is set to 0.5 to 2 WI. The pectin-containing extract is preferably supplied at a linear velocity of 1-3 m/sec. The processing pressure for pectin-containing extract depends on the above-mentioned gap spacing and the linear velocity of the extract, but it is usually 2.
~5 Kf//d, and the treatment temperature is not particularly limited, but is usually about 20 to 30°C.
In addition, if the treatment can be carried out in a single hour, it is also possible to carry out the treatment at a temperature of 50 to 60° C. in order to reduce the viscosity of the pectin solution. If you wash the squeezed lees of mandarin oranges, tomatoes, etc. with water, press them to remove water-soluble sugars, and extract the pressed lees with hydrochloric acid,
A pectin-containing extract is obtained, but in the present invention,
Preferably, fibrous powdery pectin mass obtained by drying the pressed lees is used as the extraction raw material.

Because pectin mass contains virtually no sugar, it does not spoil, is stable, and has excellent storage and handling properties. This is because manufacturing can be carried out. To extract pectin from pectin mass, usually add 1% hydrochloric acid, which is about 30 times the weight of pectin mass.
This is carried out by heating to a temperature of 70 to 80°C and stirring.

The extract thus obtained is centrifuged and then subjected to membrane treatment as described above. Typical properties of the extract are a pectin concentration of about 0.5 to 1%, a pH of about 4 to 5, a Brix concentration of about 2 to 3, and it is usually concentrated about 5 to 10 times. Pectin is precipitated by adding approximately the same volume or more of a water-miscible organic solvent, such as ethanol, to this concentrate.
This is separated, pressed and dried to obtain pectin. If desired, the pectin thus obtained may be further purified by treatment with activated carbon, ion exchange resin treatment, etc. According to the present invention, as described above, since a pectin-containing extract is processed in a so-called laminar flow membrane module, the extract is subjected to shear force when forced to pass through a narrow gap, and thus The concentration polarization of pectin and the formation of a pectin film on the surface are effectively prevented, and as a result, according to the present invention, the water permeation rate does not significantly decrease over time, making it possible for the first time to recover pectin in a practical and economical manner. It was summer.

Example saponified ethylene monovinyl acetate copolymer (saponification degree 99
70 or more) with a molecular weight cutoff of 20,000 and an inner diameter of 11.
The outer diameter is 9.7mm at the center of the 5-inch tubular ultrafiltration membrane. A membrane module was produced by inserting and fixing a rod-shaped spacer in which the gap between the membrane and the spacer was set to 0.9w1t.

Add 30 times the amount of 1% hydrochloric acid to pectin mass and add 70 to 8
Heated to 0°C, stirred, pectin content 0.9%, Bri
x concentration 2.0, pH 4.3 extract was obtained, and this extract 5
01 at an average pressure of 2 Kft/d, temperature of 25°C, and linear speed of 2.8
The extract was concentrated to 101 m/s by circulating it through the membrane module.

Claims (1)

[Claims] 1. A pectin-containing acidic extract is supplied as a thin laminar flow into a narrowly spaced gap between two semipermeable membranes or a semipermeable membrane and a spacer, and then concentrated. 1. A method for producing pectin, which comprises adding a water-miscible organic solvent to a concentrated solution obtained by precipitating pectin. 2. The method for producing pectin according to claim 1, wherein the pectin-containing acidic extract is an extract from pectin trout.