TREHALOSE-RICH YEAST EXTRACT

Abstract

The present invention relates to a method for preparing a trehalose-rich yeast extract, said method comprising a step in which yeast cells are enzymatically disrupted by use of one or more proteases. The present invention further relates to a novel trehalose-rich yeast extract obtainable by the method of the invention. The novel trehalose-rich yeast extract comprises an amount of at least 15% (w/w) trehalose, based on dry matter. The invention also relates to the use of the novel trehalose-rich yeast extract as an additive in a cosmetic, pharmaceutical, food or beverage product.

Claims

1. Method for preparing a trehalose-rich yeast extract comprising a trehalose content of at least 15% (w/w) based on dry matter, said method comprising (a) fermenting yeast cells in a suitable medium; (b) subjecting the yeast cells to abiotic stress; (c) subjecting the yeast cells to a temperature of at least 70° C. to inactivate yeast enzymes; (d) incubating the yeast cells with a least one peptidase enzyme; and (e) removing non-soluble cell components after peptidase treatment; and (f) obtaining the trehalose-rich yeast extract.

2. The method of claim 2, wherein the yeast cells belong to the genus Saccharomyces, and more preferably Saccharomyces cerevisiae.

3. The method of claim 1, wherein step (b) includes culturing the yeast cells at an increased temperature, preferably at a temperature of at least 40° C.

4. The method of claim 1, wherein peptidase treatment in step (d) includes incubation with at least one endopeptidase and/or at least one exopeptidase.

5. The method of claim 1, wherein peptidase treatment in step (d) is carried out at a pH of 4-9.

6. The method of claim 1, wherein removing non-soluble cell components after protease or peptidase treatment in step (e) includes centrifugation.

7. The method of claim 1, wherein said method further comprises drying the trehalose-rich yeast extract obtained in step (f).

8. Trehalose-rich yeast extract obtainable by a method of claim 1.

9. Trehalose-rich yeast extract, comprising a trehalose content of at least 15% (w/w) based on dry matter.

10. Trehalose-rich yeast extract of claim 9, wherein the trehalose content is at least 20%, at least 25%, or at least 30% (w/w) based on dry matter.

11. Trehalose-rich yeast extract of claim 9, wherein the trehalose content is at least 30%, at least 35%, at least 40% (w/w) or at least 45% (w/w) based on dry matter.

12. Trehalose-rich yeast extract of claim 9, wherein the protein content is at least 20%, more preferably at least 25% (w/w) based on dry matter.

13. Trehalose-rich yeast extract of claim 9, wherein the RNA content is between 1-30% (w/w) based on dry matter.

14. Pharmaceutical composition, cosmetic composition, food product or beverage product comprising the trehalose-rich yeast extract of claim 9.

15. Use of a trehalose-rich yeast extract of claim 9 as an additive in a pharmaceutical, cosmetic, food product or beverage product.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0053] FIG. 1 shows a schematic overview of a preferred embodiment for preparing a trehalose-rich yeast extract powder according with the invention and prepared in accordance with Example 1 described herein below.

EXAMPLE

[0054] The following example is provided in order to illustrate the invention. It should however be understood that the scope of the invention is not limited by the example. A skilled person will understand that several modifications can be made without deviating from the scope of the invention.

Example 1: Preparation of a Trehalose-Rich Yeast Extract

[0055] S. cerevisiae strain ATCC 204508 was grown in YPD medium (1% yeast extract, 2% peptone, and 2% glucose) overnight at 30° C. Next morning, fresh YPD-medium was added to the yeast cells to provide an OD600 of 0.1. The cells were cultured at 30° C. until an OD600 of 1.0 was reached. Subsequently, the exponentially growing yeast cell culture was subjected to a heat shock by increasing the growth temperature from 30° C. to 40° C. for 4 hours. The yeast cells were harvested using standard separators and washed twice with water.

[0056] In this way, a yeast cell substrate having a dry matter of about 18% and a trehalose concentration of about 9% (w/w) based on dry matter was obtained. The yeast substrate was heated to 90° C. for 1 hour to inactivate inherent yeast enzymes. Afterwards, a peptidase was added (Corolase 7089, AB Enzymes GmbH, Darmstadt, Germany) at a concentration of 0.5% (w/w) based on dry matter yeast substrate. The dry matter content was determined using a Moisture Analyzer (Mettler-Toledo GmbH, Gieβen, Germany).

[0057] The hydrolysis reaction was incubated at 55° C. for 3 hours under vigorous stirring. The pH was maintained at pH 7 using a 10% sodium hydroxide solution. The hydrolyzed mixture was then separated using a standard lab centrifuge (10 minutes, 4700 g, room temperature, Heraeus Multifuge X3R, ThermoFisher Scientific). The solid pellet was removed to gain the aqueous trehalose-rich yeast extract.

[0058] In order to get a dried and powdered product, the aqueous phase was then sterilized by heating to 90° C. for 30 minutes, and spray-dried using a Mini Spray Dryer B-290 from Büchi Labortechnik GmbH (Essen, Germany) with a constant input temperature between 133-136° C. and output temperature at 93 ±2° C. The final powdered product was analyzed for its trehalose content resulting in a concentration of 25.3% (w/w) trehalose of dry matter.