Peptides containing tryptophan

Abstract

The present invention relates to a composition comprising a tryptophan-containing peptide and having a Trp/LNAA ratio of more than 0.1 for decreasing eating or appetite during or after stress.

Claims

1. A method for reducing eating or deceasing appetite comprising administering to a person in need of said reducing eating or decreasing appetite, a lysozyme hydrolysate comprising Trp-containing peptides, wherein the lysozyme hydrolysate is characterized by having a molecular Trp/Large Neutral Amino Acid (LNAA) ratio of higher than 0.15 and a degree of hydrolysis (DH) of between 5 and 45; and wherein the hydrolysate is administered to the person during a time when the person is experiencing stress.

2. The method according to claim 1 wherein the stress is acute stress.

3. The method according to claim 1 wherein the lysozyme hydrolysate is in the form of a food, beverage, or dietary supplement.

4. The method according to claim 3 wherein the food is in the form of a beverage.

5. The method according to claim 3 wherein the dietary supplement is in the form of a tablet, capsule, soft gel, gelcap, liquid or powder.

6. The method of claim 1 wherein the lysozyme is hen egg lysozyme.

7. The method of claim 2 wherein the lysozyme is hen egg lysozyme.

8. The method of claim 3 wherein the lysozyme is hen egg lysozyme.

9. The method of claim 4 wherein the lysozyme is hen egg lysozyme.

10. The method of claim 5 wherein the lysozyme is hen egg lysozyme.

Description

LEGENDS TO THE FIGURE

(1) FIG. 1 The total food intake during interview preparation following tryptophan-rich hydrolyzed (M) and placebo protein (K) intake.

MATERIALS AND METHODS

(2) Materials

(3) Subtilisin under the commercial name of Protex 6L was obtained from Genencor (Leiden, The Netherlands). Lysozyme was obtained as Delvozyme L (22% dry matter) from DSM Food Specialities (Delft, The Netherlands).

(4) Amino Acid Analysis

(5) Amino acid analyses were carried out according to the PicoTag method as specified in the operators manual of the Amino Acid Analysis System of Waters (Milford, Mass., USA). To that end samples were dried and directly derivatised using phenylisothiocyanate. The derivatised amino acids present were quantitated using HPLC methods as described. As during the usual acid hydrolysis Trp and Cys are destroyed, special methods were used to quantitate these two amino acids. To prevent Cys degradation during hydrolysis, this amino acid is first oxidized to cysteic acid using hydrogen peroxide and then quantitated. The analysis of tryptophan is based on a slightly modified Waters procedure. In this procedure an aliquot of the peptide solution is dried under vacuum and then hydrolysed during 1 hour at 150 degrees C. under nitrogen in 4M methane sulphonic acid containing 0.2% tryptamine. The reaction product is directly quantitated using HPLC equipped with an Alltech Altima C18 column and fluorescence detection.

(6) Degree of Hydrolysis

(7) The Degree of Hydrolysis (DH) as obtained during incubation with the various protolytic mixtures was monitored using a rapid OPA test (Nielsen, P. M.; Petersen, D.; Dambmann, C. Improved method for determining food protein degree of hydrolysis. Journal of Food Science 2001, 66, 642-646).

(8) The following Examples illustrate the invention further.

EXAMPLES

Example 1

Hydrolysing Lysozyme using Protex to Produce a Tryptophan-Rich Hydrolysate

(9) A solution containing 10% (w/w) pure lysozyme was adjusted to pH 8.2 using NaOH and heated to 52 degrees C. Hydrolysis was started by adding 25 microliter of Protex/g of protein present. Under continuous stirring and maintaining the pH at 8.2, the hydrolysis was continued for 5.5 hours to yield an almost clear solution without a visible precipitate. After a heating step to inactivate the Protex activity, a sample was taken for DH analysis. The DH of the solution turned out to be almost 30%. The heat treated solution was ultra-filtrated over a 10 kDa filter to yield a completely clear liquid (tryptophan-rich hydrolysate or tryptophan-rich hydrolyzed protein.

Example 2

Reduction of Stress-Induced Snacking Using a Tryptophan-Rich Hydrolysate

(10) The study was conducted according to a double-blind placebo-controlled crossover design. During two experimental sessions, each of 42 participants visited the laboratory to monitor their food intake before and after acute stress exposure and following either tryptophan-rich hydrolyzed protein (THP, see Example 1) or placebo protein (PLC) intake. The order of the dietary condition was counterbalanced over the two test days with a washout period of at least one week.

(11) Before each test day participants were instructed to refrain from alcohol for at least 36 hours and to fast 12 hours before the sessions; only water or tea without sugar was permitted.

(12) After arrival, volunteers consumed either the THP or PLC drink. Then, participants were enabled to rest (reading or watching TV) for 2 hours. While seated in a separated room, each participant was then instructed to prepare for an interview to an unknown University staff-member panel. During this 5 minutes preparation phase, participants had free access to pre-weighed portions of snack foods and were instructed to eat as much as they wished. After the preparation phase, each pair of participants was brought together in a larger experimental room to conduct a 15 minute stress-inducing interview. After completion of the stress-inducing interview procedure, participants had 5 minutes of free access to pre-weighed portions of snack foods.

(13) Dietary Manipulation

(14) During both experimental sessions, a drink was consumed containing either tryptophan-rich egg protein hydrolysate, THP (DSM Delft; The Netherlands) or placebo casein protein hydrolysate (PLC, DSM Delft; The Netherlands). Key characteristics of the product are given in Table 1.

(15) TABLE-US-00001 TABLE 1 Composition of the standard protein (PLC) and tryptophan- rich protein hydrolysate (TPH) condition. Source Product (g) Trp (mg) TRP/LNAA (mol/mol) PLC 4 g/200 ml 32 0.02 TPH 4 g/200 ml 235 0.21

(16) TABLE-US-00002 TABLE 2 Amino acid profile of the protein used Amino acid profile (g) TPH PLC Isoleucine 143 152 Leucine 231 300 Phenylalanine 105 148 Tyrosine 137 176 Valine 131 204 Tryptophan 235 32

(17) Food Intake

(18) To measure snacking behavior, participants were presented with a food tray before (preparation) and after stress exposure; containing pre-weighed portions of snack foods (mini candy bars, pretzels and nuts). Each time after preparation and after completion of the public speaking (interview) task, the food container was weighted to determine the total amount of food intake.

(19) Results

(20) Analyses revealed a main Treatment effect (P=0.037), indicating a total reduction of food intake of 21 g after the THP (34 g27 g) compared to PLC (55 g50 g) (see FIG. 1) which demonstrates that lysozyme hydrolysate and other tryptophan-containing hydrolysate which comprises tryptophan-containing peptide decreases snacking behaviour during stress.