FI63852C - FOERFARANDE FOER SKALNING AV FRUKTER OCH GROENSAKER - Google Patents

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Jj & i6 (11) UTLÄGGNINGSSKRIFT 00 (3 5 2 • C (4S) p ^ Ί ^ ^ (51) Kv.ik? /Int.a.3 A 23 N 7/01 FINLAND — FINLAND (21) PVMnttlhtkenw · —Ptt « nt * mMcn <n (790U6l (22) Hkk * ml «pftlvt - Anattknlnffdag 12.02.79 ^ '(23) Alkuptlvt — Glkl | hM * da {12.02.79 (41) Tullut JulklMkd - Bllvlt offwttllg] _Q qQ γρ I * rM «Xh.ni. ·» Nlhd.ilulpwwn „rnant · ocn ngiltiritynliin Anaftku utlagd och utUkrtftan puMlearad 31.05.83 (32) (33) (31) Pyydetty« wcdkeM * —B «| ird prtoritM 17.02.78

Denmark-Darmark (DK) 7 2 2/78 (71) Aktieselskabet De Danske Spritfabrikker, Raffinaderivej 10, 23ΟΟ K ^ benhavn S, Denmark-Danmark (DK) (72) Peter Fog Laursen, K ^ benhavn, Denmark-Danmark (DK) ) (7M Oy Kolster Ab (5 ^) Method for peeling fruit and vegetables - Förfarande för skalning av frukter och grönsaker

The invention relates to a method for peeling fruits and vegetables by heating with aqueous alkali.

In known methods for peeling fruits and vegetables by heating with aqueous alkali, sodium hydroxide or potassium hydroxide has been used as the alkali, as it has been considered necessary to use the strongest possible alkali to remove the skins. However, the method has significant drawbacks, such as requiring too long a heating to give a suitable degree of peeling, which makes it expensive in terms of thermal energy and only suitable for peeling fruits and vegetables which are desired when cooked but less suitable for peeling fruits and vegetables. are not cooked or softened, e.g., because they are mechanically treated after peeling, which is difficult to do with a soft material, e.g., chopping the onion and cutting the potatoes into chips.

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It is also known to peel fruits and vegetables by heating with aqueous solutions of ammonium salts, which are clearly weaker alkalis than sodium and potassium hydroxide. However, this method is very inconvenient or expensive, because in practice it can only be carried out in pressure vessels, because ammonia is otherwise removed when heated.

According to the invention, it has now been found that the disadvantages of the known methods for peeling fruits and vegetables can be eliminated by using, in whole or in part, potassium carbonate and / or potassium phosphate as alkali. This results in faster peeling than using sodium or potassium hydroxide and thus better utilization of the capacity of the device and can be used with open tanks.

Peeling of fruits and vegetables in this context means the removal of the outermost cell layer from the plant in question, this outermost layer having either the character of an actual peel that is clearly distinguishable from the rest of the fruit or vegetable, such as potatoes and apples, or the outermost layer , such as in an onion with no sharp line between a dry and juicy skin.

Peeling of fruits and vegetables is not normally carried out to a degree of peeling of 100%, i.e. the peeling would be 100% removed from the surface, as this takes too long and then changes the interior of the fruit or vegetable. In general, it can be calculated that the degree of peeling to 80-100% is satisfactory, depending on the plant species.

The invention is further illustrated by the following examples, all of which are performed by immersing the fruits or vegetables in a heated aqueous alkaline solution and are kept there until the estimated acceptable degree of peeling is reached. They are then removed from the peeling liquid and rinsed with water and the peeled surface is measured as a percentage.

Example 1 Potatoes Bintje potatoes were used and the peeling liquid was kept at 90 ° C. The chemicals used were 9 g K 2 CO 2 / l and 56 g KOH / l. This resulted in an exfoliation rate of 85% in six minutes. If potassium hydroxide 3 63852 is used alone at a concentration giving the same potassium ion concentration, namely 63 g KOH / l, only a degree of peeling of 65% was achieved in six minutes.

The comparison required an exfoliation time of eight minutes to reach the same exfoliation percentage when the chemicals used were the corresponding sodium compounds at a concentration that gives the normality of the same enrichment solution, namely 7 g Na 2 CO 3 / l and <40 g NaOH / l.

Example 2

The fact that potassium ion alone as a difference from sodium ion is not decisive for the result is seen in an additional comparative experiment using Bintje potatoes of a different origin than in Example 1 and again keeping the peeling liquid at 90 ° C. When the chemicals used were 69 g and 42 g KOH / 1, a peel rate of 75% was achieved in six minutes, whereas only a peel rate of 35% was achieved when the chemicals used were 74.5 g KCl / 1 and 42 g KOH / 1.

Example 3 Potatoes Bintje potatoes were used and the peeling liquid was kept at 90 ° C. The chemicals used were 40 g K 2 PO 4 and 46 g KOH / l. This resulted in a 90% degree of peeling in six minutes.

The comparison required an exfoliation time of eight minutes to reach the same degree of exfoliation when the chemicals used were the corresponding sodium compounds at a concentration that gives the same exfoliation solution normality, namely 31 g Na 2 PO 3 / l and 33 g NaOH / l.

Example 4 Apples Spartan apples were used and the peeling liquid was kept at 70 ° C. The chemicals used were 35 g K2CO3 / 1 and 21 g KOH / 1. A degree of peeling of 85% was reached in six minutes.

When the chemicals used were the corresponding sodium compounds at a concentration that gives the normality of the same exfoliating solution, namely 27 g Na 2 CO 3 and 15 g NaOH / l, it took 10 minutes to reach a degree of exfoliation of 80%.

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Example 5 Apples Spartan apples were used and the peeling liquid was kept at 70 ° C. The chemicals used were 35 g KgPO 4 and 18 g KOH / l. In this case, a degree of peeling of 90% was reached in six minutes.

In comparison, a peeling time of 10 minutes was required to achieve 85% peeling when the corresponding sodium compounds were used at a concentration which gives the normality of the same peeling solution, namely 27 g Na 2 PO 3 and 13 g NaOH / l.

Example 6 Apples Springrove apples were used and the peeling liquid was kept at 70 ° C. When the chemicals used were 69 g and 28 g KOH / l, a 100% peel rate was reached in six minutes. In contrast, when the chemicals were 74.5 g KCl and 28 g KOH, no peeling was achieved at all in six minutes.

Example 7 Onion Zittauer onion was used and the peeling liquid was kept at 80 ° C. When the chemicals used were 9 g and 14 g KOH / l, an exfoliation rate of 85% was reached in six minutes.

A treatment time of 10 minutes was required to reach the same degree of exfoliation when the chemicals used were the corresponding sodium compounds at a concentration which gives the same exfoliation fluid normality, namely 7 g of Na 2 CO 3 and 10 g of NaOH / l.

Example 8 Onion Zittauer onion was used and the peeling liquid was kept at 80 ° C. When 35 g of K 2 PO 2 was used as the chemical, a degree of peeling of 85% was reached in six minutes. The use of 27 g of Na 2 PO 4 / l gave a degree of peeling of 70% in 10 minutes.

Example 9 Onion Stuttgarter onion was used and the peeling liquid was kept at 70 ° C. When 71 g of K 2 PO 2 / l (giving a normality of 1) was used as the chemical, a peel rate of 90% was reached in 10 minutes. 84 g KOH / 1, which gives the same exfoliation solution, gives a degree of exfoliation of 10% in 10 minutes, and 60 g NaOH / 1, which also gives the normality of the same exfoliation solution, gives an unsatisfactory 30% degree of exfoliation in 10 minutes.