Pea proteins with improved flavour, production method, and industrial uses

Abstract

The invention relates to pea proteins having improved flavour, a method of producing same involving wet grinding, and the use of these proteins in a food or pharmaceutical composition.

Claims

1. A pea protein product, having a 3-methylbutanal content greater than 3000 ppb.

2. The pea protein product as claimed in claim 1, wherein the benzaldehyde content is greater than 60 ppb.

3. A process for the extraction of pea proteins, comprising the steps of: a) adding peas to an aqueous solution, the temperature of which is between 70° C. and 90° C. in order to obtain a water/pea suspension; b) heat treatment of the suspension obtained during stage a), the temperature of said suspension being maintained between 70° C. and 90° C. for 2 to 4 min; c) cooling the peas of the suspension obtained during stage b); d) milling the peas resulting from stage c) in an aqueous medium in order to obtain an aqueous suspension of milled peas; and e) extraction of proteins from the aqueous suspension obtained during stage d) so as to separate the proteins from the other constituents of the aqueous suspension of stage d).

4. The process as claimed in claim 3, wherein the cooling stage c) is carried out in a new aqueous solution after draining that used during stages a) and b).

5. The process as claimed in claim 3, wherein the pH of the aqueous solution of stage a) is adjusted to between 8 and 10.

6. The process as claimed in claim 3, wherein the pH of the aqueous suspension of milled peas at the end of stage d) is adjusted to between 8 and 10.

7. A pea protein product, obtained by the extraction process as claimed in claim 3.

8. A food or pharmaceutical composition, comprising the pea protein product according to claim 1.

9. A food or pharmaceutical composition, comprising pea proteins obtained by the extraction process as claimed in claim 3.

Description

EXAMPLE 1: PREPARATION OF A PEA PROTEIN ACCORDING TO THE INVENTION

(1) 0.8 kg of peas are employed. The external fibers of the peas are first of all separated from the seeds by crushing (mechanical separation of the external hull and the pea seed) and skin removal (sorting of the external hulls and of the pea seeds using compressed air). The peas are placed in a receptacle containing 1.6 liters of demineralized water heated to 80° C. The temperature of 80° C. is maintained for 3 minutes. The peas are separated from the aqueous solution by filtration on a sieve, the mesh size of which is 2 mm. The peas are subsequently placed for 5 minutes in a second receptacle containing 1.6 liters of demineralized water, the temperature of which is regulated at a temperature of 7° C. This cooling is continued until the temperature of the peas is less than or equal to 10° C. The peas are separated from the aqueous solution by filtration on a sieve, the mesh size of which is 2 mm. The peas, weighing 1.3 kg due to absorption of water, are introduced into the chamber of a mill of Robot Coupe Blixer 4VV type. Milling of the pea is carried out at maximum speed for 1.5 minutes. Then, still while milling at maximum speed, 2.7 liters of demineralized water are added over a period of 3 minutes. Finally, the milling is continued for a period of 0.5 minute. A homogeneous water/pea milled product titrating 20% DM is obtained in the end. This milled product is centrifuged for 5 min at 5000 g. The supernatant, in which the proteins are concentrated, is adjusted to pH 5 and then heated at 60° C. for 10 min in order to cause the proteins to flocculate. The protein flock is recovered by centrifuging at 5000 g for 5 min. The flock is resuspended in a volume of water which makes it possible to obtain a fluid suspension in order to be able to correct its pH to 7 with hydrochloric acid. This flock is subsequently lyophilized. A pea protein titrating 81% protein/DM and 95% DM is obtained. The final product is referenced “Pea protein of the invention according to example 1”.

COMPARATIVE EXAMPLE 1: PREPARATION OF A PEA PROTEIN ACCORDING TO THE PRIOR ART WO2015071499

(2) 0.8 kg of peas are employed. The external fibers of the peas are first of all separated from the seeds by crushing (mechanical separation of the external hull and the pea seed) and skin removal (sorting of the external hulls and of the pea seeds using compressed air). The peas are then subjected to lactic fermentation in drinking water containing 10.sup.8 cfu of the Lactobacillus fermentum strain. The fermentation was carried out in anaerobic mode, in a closed chamber, containing 400 kg of peas per m.sup.3, without degassing, at 40° C., until a pH of 4.2 was reached. The peas are subsequently separated from the fermentation medium by filtration and are then rinsed with an equivalent volume of demineralized water. The peas are introduced into the chamber of a mill of Robot Coupe Blixer 4VV type. Milling of the pea is carried out at maximum speed for 1.5 minutes. Then, while still milling at maximum speed, a certain amount of demineralized water is added over a period of 3 minutes in order to reach approximately 20% DM in the end. Finally, the milling is continued for a period of 0.5 minute. A homogeneous water/pea milled product is obtained. This milled product titrating approximately 20% DM is centrifuged for 5 min at 5000 g. The supernatant, in which the proteins are concentrated, is heated at 75° C. for 15 sec. The supernatant is subsequently adjusted to pH 4.7 in order to obtain an isoelectric flocculation of the proteins. The protein flock is recovered by centrifuging at 5000 g for 5 min. The final product is lyophilized, which product will be referenced “Pea protein of the prior art according to comparative example 1”.

COMPARATIVE EXAMPLE 2: PREPARATION OF A PEA PROTEIN ACCORDING TO THE PRIOR ART WO2017120597

(3) 90 g of Nutralys® S85F (commercial pea protein isolate) is mixed with 750 g of drinking water in a stirred receptacle. The pH is adjusted to 9 by addition of 6N sodium hydroxide and the mixture is thus stirred for 5 min. A sufficient amount of 4M CaCl.sub.2 is subsequently added in order to obtain a concentration of CaCl.sub.2 of 30 mM. The pH is subsequently adjusted to 4.6 with 6N hydrochloric acid. The solution is centrifuged for 5 min at 2200 g. The supernatant is removed and the pellet is washed by introduction of an amount of water corresponding to 15 times the weight of pellet. The solution is centrifuged again for 5 min at 2200 g. The pellet is recovered and then lyophilized. The final product will be referenced “Pea protein of the prior art according to comparative example 2”.

EXAMPLE 2: METHODOLOGY OF A SENSORY PANEL WHICH MAKES IT POSSIBLE TO DISTINGUISH THE FLAVORS OF PEA PROTEINS

(4) The panel is made up of 30 people who are experts in tasting pea protein in water.

(5) The products were suspended at 5% by weight in Evian® brand water, with 0.3% by weight of sucrose, and homogenized using a hand-held blender.

(6) They are subsequently presented to the panelists at ambient temperature.

(7) The tasting conditions were as follows:

(8) in the sensory analysis laboratory: individual tasting cubicles, white walls, calm atmosphere (to facilitate concentration); white light (to have exactly the same view of the product); at the end of the morning or the afternoon (to be at the height of the sensory capabilities); products rendered anonymous with a three-figure code (to prevent the code from influencing the assessment of the products); products presented in a random order (to prevent order and persistence effects).
The methodology employed to compare the products was Free-Choice Profiling (Williams and Langron, 1984). It is a matter of comparing the products with one another by carrying out a succession of gradings: the panelists choose the descriptors which seem to them to be the most relevant for distinguishing the products from one another and grade the products according to these descriptors, as shown in the table below:

(9) TABLE-US-00001 not quite quite Sensory perceived weak weak medium strong strong descriptor 0 1 2 3 4 5 Pea smell 457 678 910 133 452 . . .
The list of the descriptors presented to the panelists was as follows:

(10) TABLE-US-00002 acidic cooked oats cardboard citrus butter fruits acidulated stock chemical almond fermented bitter cereals glue floral cheese astringent mild toasted coconut yeast burnt spicy flour detergent fresh rancid walnut salty milky metallic apple grainy/ sandy sweet pea paper wet mop potato soap crushed dust earth vegetable dried pea mashed rice potato

EXAMPLE 3: CONCLUSIONS OF THE COMPARISON OF THE DIFFERENT PROTEINS

(11) The organoleptic evaluations carried out using the methodology described in example 2 are summarized in the table below.

(12) The products tested are the pea proteins produced according to example 1 and comparative examples 1 and 2, as well as two commercial proteins: Nutralys® S85F and Pisane® B9.

(13) TABLE-US-00003 Sensory analysis Sample Pea flavor Bitter flavor Nutralys ® S85F 4 4 Pisane ® B9 4 4 Pea protein of the 1 1 invention according to example 1 Pea protein of the prior 4 4 art according to comparative example 1 Pea protein of the prior 4 4 art according to comparative example 2
It is observed that the pea protein obtained by the process of the invention exhibits a “pea” flavor and a “bitter” flavor which are much lower than those of the pea proteins of the comparative examples and of the commercial pea proteins tested. The pea protein of the invention can thus be advantageously introduced into a food or pharmaceutical composition as a result of its neutral taste.

EXAMPLE 4: METHODOLOGY FOR ANALYSIS BY ITEX GC/MS IN ORDER TO QUANTIFY THE CONTENT OF 3-METHYLBUTANAL AND BENZALDEHYDE IN THE PEA PROTEIN

(14) Analysis by In-Tube Extraction (ITEX) followed by gas chromatography coupled with mass spectrometry (GC/MS) makes it possible to quantify the contents of volatile organic compounds in the pea protein.

(15) First of all, an extraction of the compounds is carried out with the succession of following stages:

(16) 1. 0.5 g of pea protein sample to be analyzed and 10 ml of an acetone/water (80/20) mixture are introduced into a 15 ml vial 2. stirring is carried out at ambient temperature (approximately 20-25° C.) for 30 min and then the mixture is left to separate by settling by leaving to stand 3. the supernatant liquid phase is recovered by filtration on a 0.45 μm filter in a 10 ml vial of headspace type 4. the acetone/water phase is evaporated to dryness under a stream of nitrogen 5. the headspace vial is closed
An analysis by ITEX GC/MS is subsequently carried out. The commercial apparatus used is a Bruker Scion SQ 456-GC GC/MS equipped with a CTC CombiPal autosampler with ITEX option.
The ITEX analysis parameters are as follows: Syringe temperature 100° C. Trap temperature 40° C. Incubation temperature 100° C. Stirring speed 500 rpm Extraction volume 1000 μl Extraction number (Extraction strokes) 200 Extraction rate 1000 μl/s Pull-up delay 2000 ms Desorption temperature 300° C. Desorption rate 100 μl/s Injection rate 100 μl/s Trap cleaning temperature 300° C. Trap cleaning time 20 min
The GC/MS analysis parameters are as follows: Column Vf-Wax 30 m*0.25 mm; df 0.25 μm Prog T° C.: 3 min at 50° C., 5° C./min up to 230° C., 20 min at 230° C. Split mode injector 1:10 250° C. Helium: 1 ml/min
Finally, the integration of the data obtained on the GC/MS chromatogram is carried out by selectively metering 3-methylbutanal and benzaldehyde. In order to do this, standard samples of these products are used and the procedure is carried out according to the general knowledge of a person skilled in the art.
The results obtained with the commercial samples and with the samples obtained in the preceding examples of this patent application are presented in the table below:

(17) TABLE-US-00004 ITEX GC/MS analysis (in ppb) Sample 3-Methylbutanal Benzaldehyde Nutralys ® S85F 1614 31 Pisane ® B9 526 37 Pea protein of the 3562 68 invention according to example 1 Pea protein of the prior 597 24 art according to comparative example 1 Pea protein of the prior 2022 51 art according to comparative example 2
By correlating the results of the sensory analysis of example 3 and the results obtained by ITEX GC/MS analysis, it is apparent that the sample obtained according to the invention is the only one to exhibit a 3-methylbutanal content of greater than 3000 ppb and a benzaldehyde content of greater than 60 ppb.
It is thus apparent that the proteins exhibiting a high content of 3-methylbutanal and of benzaldehyde have a better organoleptic quality, in particular as regards the “bitter” and “pea” flavors, in comparison with that of the pea proteins of the comparative examples and of the commercial pea proteins tested.