Process for treating yeast with B-1, 3-glucanase to produce microcapsules for enclosing hydrophobic liquids

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The yeast cell wall of microcapsules which is used in the present invention is a physically and chemically relatively strong film comprising glucan, mannan, chitin or the like, and as a result of extensive research conducted by the inventors on method of controlling the strength of the cell wall without damaging the function to protect the core material which should be possessed by the microcapsules, it has been found that a large amount of the hydrophobic liquid can be rapidly contained in the yeast cells by treating the yeast cells in an alkaline aqueous solution for a given period with heating and stirring or treating the yeast cells with an enzyme which dissolves the cell wall and then mixing the thus treated cells with the hydrophobic liquid to be confined therein, followed by encapsulation and that physical strength as microcapsules and release of the liquid contained therein can be freely controlled by changing the treating conditions depending on usages of the capsules.
Thus, the present invention has been accomplished.
It depends on usages of microcapsules which treatment should be employed, but when the microcapsules are used for pressure-sensitive copying papers, the treatment with enzyme is preferred, taking into consideration the time required for the treatment and the coloration of yeast.
The process for producing microcapsules of the present invention fundamentally comprises the following steps: (1) a step of preparing a dispersion of yeast cells, (2) a step of treating yeast cells with an alkaline aqueous solution or an enzyme, (3) a step of preparing a hydrophobic liquid and mixing the hydrophobic liquid with the dispersion of yeast cells, and (4) a step of encapsulation with heating and stirring.
The steps (2) and (4) can be simultaneously carried out.
If desired, steps of washing, dehydration, drying and the like of yeast cells can be incorporated into the above steps.
PH of the alkaline aqueous solution used for controlling the strength of yeast cell wall is usually at least 8, preferably 9