GB2095534A

GB2095534A - Green fodder preservative

Info

Publication number: GB2095534A
Application number: GB8204407A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-03-30
Filing date: 1982-02-15
Publication date: 1982-10-06
Also published as: SE8200625L; DE3208134C2; NO820977L; SE454477B; NL191824C; FI63328C; NO154542B; NO154542C; DK159365C; FR2502468A1; GB2095534B; FR2502468B3; FI810979L; NL191824B; DK142182A; FI63328B; DE3208134A1; NL8200629A; DK159365B

Abstract

The composition contains a @ constituent which increases the concentration of hydrogen ions, and @ a benzoic acid a salt or derivative thereof such as p-hydroxybenzoic acid or its esters. The amount of the constituent @ may be 40-98% by weight and the amount of the benzoic acid constituent 2-60% by weight. Specified constituents @ are formic acid or a mineral acid, or formates with acid phosphates.

Description

SPECIFICATION A preservative composition for the preservation of grown fodder and e Ifi The present invention relates to a preservative composition for the preservation of green fodder and the like, the composition containing a constituent which increases the concentration of hydrogen ions in the fodder to be preserved, e.g. a mineral acid or formic acid, or salts of formic acid together with an acidic phosphate compound.

The use of acids as preservatives in the preservation of green fodders is a commonly known method of preparing a silage of high quality. The best known and most reliable procedure is based on the AlV process, according to which the pH of the fodder mass is lowered to the range 3-4 by means of an acid addition. Initially, only strong mineral acids, such as a mixture of hydrochloric acid and sulfuric acid, were used in the AIV process, but later they have been replaced in particular by formic acid. Formic acid has also been used as a salt the cation of which is calcium, magnesium or sodium, together with a phosphate such as urea phosphate and/or monocalcium phosphate.

Owing to the buffering effect of the fodder to be preserved, even obtaining a pH of 4 directly by means of an acid addition has in practice proven to be inadvisable because of the large amount of acid addition required. Obtaining the desired pH range is therefore left to depend on acid-forming fermentation in the fodder, the most advantageous fermentation being pure lacticacid fermentation, which is caused by lactic-acid bacteria highly resistant to acidity.The essential significance of the acid addition is thus primarily the facet that the increasing of acidity promotes pure lactic-acid fermentation by reducing or inhibiting the growth and activity of microbes which tolerate acidity less and cause harmful fermentation, and above all of butyricacid bacteria which sharply lower the quality and useful value of the fodder and cause great losses of nutrients. The objective is thus to reduce or inhibit the competing of other microbes with lactic-acid bacteria for a joint source of energy, the sugars of the fodder material being such a source of energy.

An ideal preservative thus consists of a substance or a composition which, in addition to an immediate decreasing effect on the pH, specifically combats, without having an adverse effect on pure lactic-acid fermentation, the vital activities of the micro-organisms which compete with the lactic-acid bacteria for the source of energy. In this case the desired final level of acidity is reached as advantageously as possible by converting sugars of the fodder material to lactic acid with maximal efficiency and minimal consumption of sugars.

The preservatives or preservative compositions known thus far have not been observed to have properties which specifically inhibit harmful types of fermentation and favor lactic-acid fermentation in the manner described above, but their advantageous effect has been limited to that which is explainable by the increase caused by them in the concentration of hydrogen ions.

Now it has been surprisingly observed in accordance with the present invention that by combining a constituent which increases the concentration of hydrogen ions, and a benzoic acid constituent, a very effective preservative composition can be produced. Thus the Invention relates to a preservative composition for the preservation of green fodder and the like, the composition containing a constituent which increases the concentration of hydrogen ions in the fodder to be preserved, e.g. a mineral acid or formic acid, or a salt of formic acid together with an acidic phosphate compound, and the invention is characterized in that the composition also contains a benzoic acid constituent, which can be in the form of benzoic acid or its salt or derivative.The ratios of the constituents can vary in such a manner that the preservative composition contains approx. 40-98% by weight the constituent which increases the concentration of hydrogen ions and approx. 2-60% by weight a benzoic acid constituent calculated as benzoic acid.

Benzoic acid and its salts, as well as certain of its derivatives, are previously knovirn as preservatives, and they have also been experimented with in the preservation of green fodder.

However, with the exception of some specific cases the results of the experiments have been unsatisfactory. A possible explanation for this is that an acid addition which effectively increases the concentration of hydrogen ions has not been used in addition to the benzoic acid constituent in the previous experiments. Namely, within the amounts the use of which is acceptable both physiologically and economically, the effect of benzoic acid remains insignificant compared with the concentration of hydrogen ions, and it is entirely absent when benzoic acid is used as a salt.

On the other hand, with the preservative composition according to the present invention it is possible to obtain results which are superior to those obtained by using the constituents of the composition separately. To illustrate this, below there are presented results of grass preservation which was carried out by using various amounts of hydrochloric acid or formic acid as the constituent which increases the concentration of hydrogen ions, either without an addition of benzoic acid or by adding two different amounts of benzoic acid. In all the experiments, the benzoic acid was in the form of an ammonium salt. A similar preservation without a constituent which increases the concentration of hydrogen ions is presented for reference.

Table 1 below shows the amount of lactic acid in the fodder in percent by weight and, in parenthesis, in equivalents per one tonne of fodder.

Table 1 shows that at each of the levels of addition of "other acid", starting from zero, the amount of lactic acid formed in the fodder is more or less constant. This shows that the addition of benzoic acid did not inhibit lactic-acid fermentation. On the other hand, an increased addition of "other acid" decreased the amount of lactic acid formed, and in this respect formic acid has a stronger effect than hydrochloric acid. It can be easily observed from the amounts of lactic acid shown as equivalents in Table 1 that an equivalent addition of hydrochloric acid reduced the amount of lactic acid equivalently by about the same amount. On the other hand, an increase in the addition of formic acid equivalently reduced the amount of lactic acid definitely more.

Table 1 Lactic acid in fodder, % by weight (equiv./t) Other acid Benzoic acid, kg/t equiv./t 0 0.25 0.50 0 2.07 2.11 2.10 (230) (234) (233) 20 1.93 1.97 1.62 (214) (219) (180) HCI 40 1.75 1.77 1.73 (194) (197) (192) 60 1.55 1.46 1.52 (172) (162) (169) 20 1.71 1.83 1.80 (190) (203) (200) HCOOH 40 1.19 1.28 1.38 (132) (142) (153) 60 0.98 0.99 0.93 (108) (110) (103) Table 2 shows, in percent by weight, the concentration of reducing sugars present in the fodder at the end of the fermentation. The table shows that combining a benzoic acid addition with acids which increase the concentration of hydrogen ions decreases, at all levels of addition of the latter, the loss of sugars in types of fermentation unfavorable to preservation.The remaining amount of sugars was in the best cases equal to or even greater than that originally observed in the grass to be preserved. This can be explained only by the formation of sugars from the other carbohydrates of the fodder, sugars which remained unused in the fodder mass.

It can be clearly observed in Table 2 that the preservative composition according to the invention has the advantageous effect that it protects sugars from types of fermentation unfavorable or adverse to preservation. This effect is clearly greater when the composition is used than when its constituents are used separately.

The advantageous combined effect is most clearly shown by the lower section of Table 2. It shows that, when formic acid is used alone and when its addition is increased, the remaining amount of sugars is decreased, which is entirely contrary to the situation where hydrochloric acid is used alone. On the other hand, an examination of the effect of benzoic acid, added alone and added together with formic acid, on the remaining amount of sugar shows that the concentration of sugar at its best remained double under the effect of the benzoic acid addition (highest row), whereas, when formic acid is also present, the sugar concentration respectively remained nearly 2.5-fold as compared with the control, i.e. clearly relatively higher (two lowest rows).

Table 2 Reducing sugars in fodder, % by weight (Sugar in fresh raw material on the average 3.57% by weight) Other acid, Benzoic acid, kg/t equiv./t 0 0.25 0.50 0 1.27 1.96 2.53 20 1.97 2.73 3.31 HCI 40 2.92 3.83 3.78 60 3.11 3.67 3.54 20 2.26 2.33 2.78 HCOOH 40 1.24 2.39 3.06 60 1.11 1.43 2.66 Table 3 shows the loss of dry matter of fodder during preservation. The experimental results shown in this table further corroborate the finding that the favorable effect of benzoic acid in the preservative composition according to the invention is more than additive. This is shown by the fact that at all levels of hydrochloric acid addition the benzoic acid constituent decreased the loss of dry matter clearly more effectively than when used alone.

That which has been disclosed above is equally valid for the loss of organic matter, since in the experiments described above no compressed juice was discharged from the silos. Thus there was no loss of minerals, and the loss of organic matter can be considered as being due to the fermentation.

Table 3 Loss of dry matter during preservation, % by weight Other acid, Benzoic acid, kg/t equiv./t 0 0.25 0.50 0 12.75 8.64 8.34 20 9.45 10.80 3.70 HCI 40 6.52 3.85 2.58 60 12.93 4.47 2.90 20 7.90 8.49 10.00 HCOOH 40 19.03 13.97 10.09 60 18.22 17.62 10.72 Table 4 shows the results of a study on ethanol fermentation. Ethanol fermentation may be one reason for the losses shown above. It can be observed from the results shown in Table 4 that, when used together with hydrochloric acid, benzoic acid decreased the formation of ethanol clearly more than when used alone, Used together with formic acid the same effect is obvious, but partly relatively smaller. The explanation for this seems to be the unexpected promoting effect which formic acid has on the formation of ethanol.

Table 4 Ethanol in fodder, % by weight Other acid, Benzoic acid, kg/t equiv./t 0 0.25 0.50 0 0.75 0.53 0.

20 0.75 0.38 0.28 HCI 40 0.46 0.23 0.09 60 0.52 0.16 0.09 20 0.75 0.52 0.27 HCOOH 40 1.42 0.95 0.26 60 1.56 1.27 0.61 In order to clarify the usability of the preservative according to the invention, the effect of larger amounts of benzoic acid on the taste and digestibility of fodder was tested. As regards acids, their effects in this respect were known previously. For testing purposes, silage was prepared from grass by adding as preservative benzoic acid, in one case 1 kg and in another case 2 kg per one tonne of fresh fodder, i.e. 0.1 and 0.2% by weight. For control, fodders were prepared without preservative and by adding 5 l of a 86-percent formic acid per one tonne of fodder.

According to a Latin square, in a taste and digestibility test performed using rams no statistically significant differences could be shown between the fodders as regards the taste of fodder or the digestibility of its organic matter. Since the animals were offered only silage, it can be concluded with good grounds that benzoic acid can be added, in an amount of at least 2 kg per one tonne of fodder, as a constituent of preservative to green fodder to be preserved.

On the basis of the above, it can be regarded as clearly shown that the preservative composition according to the invention, comprising a constituent which increases the concentration of hydrogen ions and also a benzoic acid constituent, has favorable properties which are not equally diverse in previously known preservatives for green fodder, or in combinations of the same. By using very small amounts of benzoic acid in the composition it is thus possible to decrease substantially, without worsening the result of the preservation or even with simultaneously improving the result, the use of an acid which immediately decreases the pH of the fodder. This also has an economically advantageous effect when the pH is controlled by means of an organic acid such as formic acid.When less expensive mineral acids are used, the possibility of decreasing the use of acid is especially favorable because the large amounts of these acids used conventionally have a physiologically unfavorable effect on animals when they are fed large quantities of fodder.

Since the effect and effectiveness of the constituent which controls the pH can be decreased without adverse effects, it is possible in the preservative composition according to the invention also to use as the pH-controlling constituent acidic salts or their mixtures instead of free acids.

Thus it is more possible than before to discontinue the use of liquid acids and combinations of the same, which are difficult to handle and tend to cause accidents. Thus any substance, or composition of substances known per se which increases the concentration of hydrogen ions can be used as the pH-controlling constituent in the preservative composition according to the invention.

The benzoic acid constituent can be in the form of benzoic acid or its salt or as a derivative which has a similar effect as the acid or its salts. Some examples of usable derivatives are parahydroxybenzoic acid and its methyl esters and ethyl esters, which have also been approved as preservatives for foodstuffs.

The preservative composition according to the invention can be in the form of either a solid or a solution. Since benzoic acid is not soluble in acids such as hydrochloric acid and formic acid, it is suspended iri the acid as a maximally homogeneous suspension by using thickening and gelling agents known per se, e.g. agar-agar, alginates, cellulose derivatives, starch dextrin or pectin.

It is also possible to include in the preservative composition according to the invention other agents which improve the result of preservation, e.g. sugars or sugar-containing substances, lactic-acid bacteria, enzymes which break down cellulose and starch, agents which affect the aroma of the fodder, and agents which regulate the solubility of the proteins of the fodder.

A typical area of use of a preservative composition according to the invention comprises the preservation of green plant material in a space sealed off from air. Other possible applications include the preservation of grains and seeds to be stored while moist, as well as the preservation of hays and straws, in which case the preservation can, depending on the moisture content of the material, be carried out in a space either protected or unprotected from air. The proportions of the constituents in the composition can in this case vary rather widely, depending on the material in which it is used and on its properties.Thus an advantageous amount of the benzoic acid constituent in airtight preservation of fresh grass fodders is about 1 00-1000 g per one tonne of fodder, expressed as benzoic acid, and in no case should the amount of benzoic acid constituent exceed 2 kg benzoic acid per one tonne fodder. The highest proportions within the presented range are recommendable for fodder materials which contain a high amount of proteins and have a strongly predominantly alkaline mineral composition, e.g. leguminous plants. On the other hand, the smaller proportions are sufficient for low-protein materials with a less alkaline or neutral mineral composition. In a preservative composition in which formic acid is the only pH-controlling constituent it is, however, advantageous to use large amounts of benzoic acid constituent regardless of the fodder material being preserved.

The amount of the constituent which increases the acidity of the preservative composition is advantageously 20-60 acid equivalents per one tonne of fodder, when the acidity of the composition is determined by titrating it with a strong alkali to a pH value of 7. Both higher and lower amounts within the presented range are determined on the same grounds as were presented above regarding the benzoic acid constituent.

Thus the acidity-increasing constituent of a preservative composition according to the invention may vary, depending on the acid used and the use, within an approximate range of 40-98% by weight, calculated as acid, and respectively the amount of the benzoic acid constituent may vary within an approximate range of 2-60% by weight, calculated as benzoic acid.

Claims

1. A preservative composition for the preservation of green fodder and the like, the composition containing a constituent which increases the concentration of hydrogen ions in the fodder to be preserved, e.g. a mineral acid or formic acid, or salts of formic acid together with a compound of phosphorus, characterized in that the composition also contains a benzoic acid constituent, which may be in the form of benzoic acid or its salt or its derivative.

2. A preservative composition according to Claim 1, characterized in that it contains 40-98% by weight a constituent which increases the concentration of hydrogen ions and 2-60% by weight a benzoic acid constituent, calculated as benzoic acid.

3. A preservative composition according to Claim 1 or 2, characterized in that it also contains other additives known per se, such as sugars or sugar-containing substances, lactic-acid bacteria, enzymes which break down cellulose and starch, and agents which control the solubility of the proteins of the fodder.

4. A liquid-form preservative composition according to any of the above claims, in which the benzoic acid constituent is in the form of benzoic acid, characterized in that the benzoic acid is uniformly suspended in the solution with the aid of a thickening agent or a gelling agent.