US2273183A - Process for the removal of skins of filbert nuts - Google Patents

Description

Patented Feb. 17, 1942 PROCESS FOR THE REMOVAL OF SKINS OF FILBERT NUTS Edward B. Edes, Lebanon, Oreg.

N Drawing. Application March 22, 1940, Serial No. 325,368

4 Claims.

My process relates to other edible nuts as well as filberts. Heretofore, according to my knowledge of the art, the removal of the skins from the nut meats of filberts was accomplished by immersion of the nut kernels in an alkaline solution, preferably brought to and held at boiling point, so as to expedite the process; and the time fixed for such immersion was from 1 to 7 minutes, with a longer period being required if unheated alkaline solution is used. The purpose of such procedure probably was to efiect complete saponification of the oleaginous component of the nut skins; such component apparently being considered as constituting the medium providing the adherence of the skin to the nut meat.

I have discovered, however, that if'removal of the skin is attempted by an alkaline solution discoloration of the nut meat from its normal ivory color to a color resembling more or less dark mahogany will result and besides the removal of the skin is not facilitated. This discoloration is plainly seen in the marginal portion of the nut meat, if the kernel be cut crosswise to its growth axis. The discoloration may penetrate the marginal portion of the nut meat to a depth of sth of an inch. I further discovered that this discoloration of the nut is speeded and intensified by the immersion of the nut kernels in a hot or boiling alkaline solution.

The object of my invention is to accomplish the removal of the skins from the kernels without injury or discoloration of the nut meat.

My experiments show that the use of an alkaline solution appears necessary as a preliminary step for efiecting the loosening of the skins from the nut meats, and saponification of the oleaginous component of the skin is thus produced; but it is my belief that the skin contains only a small amount of oil.

I have discovered that a safe, and likewise effective way of removing the skins is to subject the nut kernels to successive immersions, first, for a limited time, in a weak, cold, alkaline solution, and then for a limited time, in a weak acid solution.

By my process the kernels are first immersed in a solution at normal temperature of approximately 3% caustic soda (sodium hydroxide), or equivalent reagent, for a period of from 1 to 4 minutes, depending upon the thickness of the skins, and the variety of the filberts to be treated, which must be taken into account by the operator. He must determine the required time of immersion, by previous tests made with a sample of nuts taken from the volume of nuts to be treated. This sample must be immersed in the alkaline solution for the minimum period, and then a kernel taken out and cut across its axis of growth and the cut surface of the nut observed. 1f immersed for too long a period of time in the alkaline solution, discoloration of the marginal portion of the nut meat will appear as above mentioned, and the time must be shortened. This step may also be controlled by watching the alkaline solution. When this begins to acquire a color resembling dark mahogany, such indicates that alkaline solution immersion has progressed to the extent permissible, and the kernels should be immediately removed from the solution. On the other hand, the immersion must also be for a suiflcient period to render the second step of my process effective for loosening the skins.

I have successfully used solutions made up with borax, carbonate of soda, or bicarbonate of soda. In short, any chemical may be employed to make the solution which I will designate this solution as an alkaline solution.

The temperature of the solution may be that of the atmosphere prevailing at the time my process is used.

The time limit of immersion of the nut kernels in the alkaline solution is critical, and therefore the time must be limited to a shorter period than would efiect deleteriously the nut meat.

The immersion of the nut kernels in the alkaline solution does not loosen the skin from the nut meat so that the skin may be removed by a dislodging force, as for example by the impingement upon the kernels of a stream of water under pressure, or equivalent procedure.

The immersion of the kernels in the alkaline solution merely puts the kernels in condition for having their skins loosened by the next step of my process. This step consists in immersing the kernels in a weak--approximately 2 to 4% acid solution hydrochloric, acetic, and citric acids have been successfully used by me for a period of from 1 to 4 minutes; the required length of immersion in the acid solution is to be determined as hereinafter stated.

Before placing the kernels in the acid solution, after their immersion in the alkaline solution, they should, preferably be thoroughly washed, so as to rinse ofi the alkaline solution adhering to the kernels, thereby reducing the cost of acid solution required by my process by avoiding waste of acid solution in the neutralizing of the alkaline solution adhering to the kernels.

After the skins have been loosened from the nut meats they may be removed by placing the processed kernels in a body of water subjected to vigorous agitation; or by the impingement up- 7 on the kernels of streams of water under pressure.

The loosening of the skins by the acid immersion so that they will readily separate from the nut meats, may be determined by placing a few of the kernels in a jar filled with water and vigorously shaking the jar. If the two steps of my process have been properly performed, the skins of the kernels will soon become detached from the nut meats and will be seen floating in the water.

If the skins do not become detached from the nut meats by this test, then either the immersion of the kernels in the alkaline or saponifying solution, or their immersion in the acid solution,,or both immersions have not been properly timed. In this connection attention must again be called to the fact that the proper limitation of the immersion of the nut kernels in the alkaline solution is a critical procedure. But slightly excessive immersion of the kernels in the acid solution is negligible.

Because of the variance in the thickness of skins in dryness and other factors in different varieties and crops of nuts, it is impossible to specify fixed periods for the immersions of the kernels in either solution; but the operator must himself more or less fix the periods of said immersions by applying his knowledge gained by experience in practising my process. In other words, the operator will by experience learn to fix such periods approximately by the appearance of the nuts or their kernels; and then by taking a sample of the volume of nut kernels to be processed and giving this sample a laboratory treatment in accordance with the requirements of my process as above described, the time periods for each immersion may be readily and safely fixed for the treatment of the whole volume of nut kernels. After the nut meats are taken from the acid solution, they must be thoroughly Washed to remove all adhering acid solution. But this is accomplished in the removal of the skins from the nut meats by the application of a skin dislodging force through water as the medium as above mentioned.

While I have described my process with reference to the removal of the skins of filberts, my invention is not to be limited to these, but covers any kind of nuts, the skins of which may be re moved by my process.

I claim:

1. The process of removing the skins of nut meats, which comprises immersing the meats with the skins thereon in a'solution of approximately 3% of one of the alkalis of the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate and borax for a period of from one to four minutes, removing the nut meats and rinsing the same in water, immersing the nut meats in a bath of about 2% to 4% solution of an acid of the group consisting of hydrochloric, acetic and citric acids for a period of from one to four minutes, removing the nut meats from the last mentioned bath, and then subjecting the material to a forcible action of water to remove the skins.

2. The process of removing the skins of nut meats, which comprises immersing the nut meats with the skins thereon in a solution of approximately 3% of one of the alkalis of the group con- I sisting of sodium hydroxide, sodium carbonate,

sodium bicarbonate and borax for a period of from one to four minutes, removing the nut meats and immersing the nut meats in a bath of about 2% to 4% solution of an acid of the group consisting of hydrochloric, acetic and citric acids for a period of from one to four minutes, removing the nut meats from the last mentioned bath and then subjecting the material to a forcible action of water to remove the skins.

3. The process of removing the skin of nut meats which consists in immersing the nut meats with the skins thereon in a solution of approximately 3% of one of the alkalis of the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate and borax, limiting the period of such immersion so as to prevent marginal discoloration of the nut meats, removing the nut meats from said solution, then immersing the nut meats in a 2% to 4% solution of an acid-of the group consisting of hydrochloric, acetic and citric acids, and continuing such 1mmersion until looseness of the skins of the nut meats is manifested, and then efiecting the removing of the skins from the nut meats by water applied with a dislodging force.

4. The process of removing the skin of nut meats which consists in immersing the nut meats with the skins thereon in a solution of approximately 3% of one of the alkalis of the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate and borax, limiting the period of such immersion so as to prevent marginal discoloration of the nut meats, removing the nut meats from said solution, rinsing the same in water, then immersing the nut meats in a 2% to 4% solution of an acid of the group consisting of hydrochloric, acetic and citric acids, and continuing such immersion until looseness of the skins of the nut meats is manifested, and then effecting the removing of the skins from the nut meats by water applied with a dislodging force.

EDWARD B. EDES.