Propionic acid based preservative agent for animal and vegetable products
The present invention relates to a preservative agent based on propionic acid, suitable for animal and vegetable products, and to the preparation and use of the same. The preservative agent is obtained by fermentation of whey or components of whey.
1. A method for preparing a preservative agent suitable for animal and vegetable products, comprising the following steps:
(i) forming a substrate consisting of whey or components of whey, an agent for avoiding microbial contamination and an alkaline buffer;
(ii) treating the substrate obtained in (i) with alginate beads; and
(iii) fermenting the substrate obtained in (ii) with live cells of co-immobilized propionic acid bacteria and lactic acid bacteria while adding a base.
2. A method according to claim 1 , wherein, in step (i) calcium carbonate is used as alkaline buffer.
3. A method according to claim 1 , wherein, in step (iii) a slurried solution of calcium hydroxide (Ca(OH) 2 ) is used as base.
4. A method according to claim 1 , wherein, in step (i) benzoic acid and/or sorbic acid are used to avoid microbial contamination.
5. A method according to claim 1 , wherein, the live cells of propionic acid and lactic acid bacteria in step (ii) have a concentration of 6.00 to 11.00 log 10 cfu/ml of preservative agent.
6. A method according to claim 1 , wherein, the fermentation product obtained in step (iv) has a pH of 4.5-5.5.
7. The method of claim 1 , comprising the further step of preparing the fermentation product as a preservative agent for preserving animal and vegetable products.
8. The method according to claim 7 , wherein the preservation agent is prepared for the ensilage of grass.
9. The method of claim 1 , comprising the further steps of:
(iv) concentrating the fermentation product thus obtained and optionally adding C 1-8 monocarboxylic acids; and
(v) adding live cells of propionic acid bacteria and/or lactic acid bacteria having antimicrobial activity to the thus obtained fermentation product.
10. A method according to claim 9 , wherein, step (iv) further comprises adding substances for the survival of bacteria, to the fermentation product.
11. The method of claim 10 , wherein the substances are glycerol and casamino acids.
12. The method of claim 1 , comprising the further steps of:
(iv) concentrating the fermentation product thus obtained and adding C 1-8 monocarboxylic acids; and
(v) adding live cells of propionic acid bacteria and/or lactic acid bacteria having antimicrobial activity to the thus obtained fermentation product.
13. A method according to claim 12 , wherein, the fermentation product obtained in step (iv) is concentrated.