Methods for increasing the digestibility of proteins in food and protein components and foods containing the same.

Abstract

Invention details;

Description

Method for improving protein digestibility in food, protein composition and food containing the same Technical Field

[0001] The invention relates to a method for improving protein digestibility in food, a protein composition and food containing the same, and belongs to the technical field of formula milk powder. Background Art

[0002] Among the three major energy-supplying nutrients, protein has aroused great interest due to its important roles in mammalian cubs, such as providing energy, promoting height, inhibiting bacteria and infection, and promoting mineral absorption.

[0003] The huge difference in protein composition between cow's milk and human milk reflects the differences in physiological characteristics and growth patterns of different species, and the nutritional value they bring is also different.

[0004] Generally, protein in food can only be absorbed after being hydrolyzed into amino acids and short peptides. Since saliva does not contain enzymes that hydrolyze proteins, protein digestion begins in the stomach, but primarily occurs in the small intestine. The enzyme that digests protein in the stomach is pepsin, which breaks it down into peptones, small amounts of peptides, and amino acids. The optimal pH for pepsin to function is 1.8-3.5. Pepsin has a coagulating effect on casein, and once formed, the curds remain in the stomach for a long time, facilitating digestion and absorption, which is very important for infants. Protein digestion in the small intestine is primarily accomplished by various proteases secreted by the pancreas (such as trypsin), which rapidly break down proteins in the small intestine into amino acids and short peptides that can be absorbed by the small intestinal epithelial cells.

[0005] It is generally believed that casein will clump together in the stomach, causing it to stay there for a long time, prolonging the gastric emptying time and the time it takes for protein to digest and absorb. The highly acidic environment in the stomach and the combined action of digestive enzymes destroy the casein micelles, which then react with acid and pepsin to form clots. Increasing the proportion of β-casein can reduce the size of the clots. However, because the spatial structure of whey protein is not easily destroyed in the stomach, existing studies have reported that whey protein is not easily digested in the stomach. Only after entering the small intestine can it be completely degraded into free amino acids and absorbed for use by the body. There is a difference in the spatial structure of α-lactalbumin and β-lactoglobulin. It is more likely to form a loose structure in the presence of gastric acid. Therefore, whether increasing the proportion of α-lactalbumin can improve digestibility is a very debatable issue.

[0006] Although protein has the above-mentioned advantages and digestibility, the digestibility of protein-containing foods such as ordinary infant formula is still not as good as breast milk during digestion by infants and young children, and needs to be improved urgently.

[0007] Summary of the Invention

[0008] In order to solve the above technical problems, the purpose of the present invention is to provide a method for improving the digestibility of protein in food, by controlling the composition and content range of protein in food, so that the protein has good digestibility.

[0009] To achieve the above object, the present invention first provides a method for improving the digestibility of protein in food, which is to control the content of α-lactalbumin in the food to about 10.5%-51.0%, and the content of β-casein in the food to about 10.0%-40.0%, wherein the above contents are all calculated based on the total protein content of the food as 100%.

[0010] According to a specific embodiment of the present invention, preferably, the content of α-lactalbumin is controlled to be about 15.0%-51.0%.

[0011] According to a specific embodiment of the present invention, preferably, the content of β-casein is controlled to be about 12.0%-40.0%, more preferably about 15.0%-40.0%.

[0012] According to a specific embodiment of the present invention, preferably, the method further comprises: controlling the content of α-lactalbumin in the food to about 15.0%-32.0%, and controlling the content of β-casein in the food to about 20.0%-32.0%, wherein the above contents are based on the total protein content of the food as 100%.

[0013] According to a specific embodiment of the present invention, preferably, the method controls the content of α-lactalbumin in the food to about 21.0%-32.0%, and the content of β-casein to about 26.0%-32.0%, and the above contents are all based on the total protein content of the food as 100%.

[0014] According to a specific embodiment of the present invention, preferably, the method controls the content of α-lactalbumin in the food to about 21.0%-32.0%, and the content of β-casein to about 29.0%-32.0%, and the above contents are all based on the total protein content of the food as 100%.

[0015] According to a specific embodiment of the present invention, preferably, the method further comprises: controlling the content of whey protein in the food to be above about 30.0%, for example, 35.0%-90.0%, preferably about 35.0%-70.0%, more preferably about 40.0%-70.0%, and further preferably about 55.0%-65.0%, all of the above contents being based on the total protein content in the food as 100%.

[0016] According to a specific embodiment of the present invention, preferably, the method further comprises: controlling the casein content in the food to be above about 10.0%, for example, 10.0%-65.0%, preferably about 30.0%-65.0%, more preferably about 30.0%-60.0%, and further preferably about 35.0%-45.0%, all of the above contents being based on the total protein content in the food as 100%.

[0017] According to a specific embodiment of the present invention, the content of whey protein and the content of casein in the food can be controlled simultaneously. Preferably, the content of whey protein in the food is controlled to be about 35.0%-70.0%, and the content of casein is controlled to be about 30.0%-65.0%, for example, 60.0% and 40.0%, 35.0% and 65.0%, 50.0% and 50.0%, 70.0% and 30.0%, all of the above contents are calculated based on the total protein content of the food as 100%.

[0018] According to a specific embodiment of the present invention, preferably, the method is to control the content of whey protein in the food to about 55.0%-65.0%, the content of casein to about 35.0%-45.0%, and:

[0019] The content of α-lactalbumin in the food is controlled to about 32.0%, and the content of β-casein is controlled to about 32.0%. Alternatively, the content of α-lactalbumin in the food is controlled to about 29.0%, and the content of β-casein is controlled to about 32.0%. Alternatively, the content of α-lactalbumin in the food is controlled to about 21.5%, and the content of β-casein is controlled to about 29.0%. The content of α-lactalbumin in the food is controlled to about 21.0%, and the content of β-casein is controlled to about 26.0%. The above contents are all based on the total protein content of the food as 100%.

[0020] The method provided by the present invention can significantly improve the digestibility of protein (especially whey protein) in food by controlling the content of α-lactalbumin (the proportion of total protein) and the content of β-casein (the proportion of total protein) in food.

[0021] According to a specific embodiment of the present invention, improving the digestibility of protein refers to improving the digestibility of animal-derived protein, such as protein derived from animal milk, especially protein derived from cow's milk.

[0022] According to a specific embodiment of the present invention, preferably, the improvement of protein digestibility in food includes at least one of the following: improving the digestibility of whey protein, increasing the types of released free amino acids, increasing the proportion of released essential amino acids EAA in the released free amino acids, increasing the production of small molecule peptides, increasing the types of characteristic peptide segments produced, and in particular increasing the proportion of released essential amino acids EAA in the released free amino acids.

[0023] According to a specific embodiment of the present invention, the food can be adult food, children's food or infant food based on the applicable population; and can be milk powder or liquid milk, such as adult milk powder, children's milk powder, infant formula milk powder, etc. based on the type.

[0024] The present invention also provides a protein composition, wherein, based on 100% of the total protein content of the protein composition, the protein composition contains approximately 10.5%-51.0% of α-lactalbumin and approximately 10.0%-40.0% of β-casein. The protein composition is capable of improving the digestibility of protein in food and can be used to implement the method for improving the digestibility of protein in food provided by the present invention, as a component combined with other ingredients to produce a food.

[0025] According to a specific embodiment of the present invention, preferably, based on 100% of the total protein content of the protein composition, the protein composition contains about 15.0%-51.0% of α-lactalbumin.

[0026] According to a specific embodiment of the present invention, preferably, based on the total protein content of the protein composition as 100%, the protein composition contains about 12.0%-40.0% β-casein, more preferably about 15.0%-40.0%, and even more preferably about 20.0%-32.0%.

[0027] According to a specific embodiment of the present invention, preferably, based on 100% of the total protein content of the protein composition, the protein composition contains about 21.0%-32.0% of α-lactalbumin and about 26.0%-32.0% of β-casein.

[0028] According to a specific embodiment of the present invention, preferably, based on the total protein content of the protein composition as 100%, the protein composition contains about 21.0%-32.0% alpha-lactalbumin and about 29.0%-32.0% beta-casein. For example, based on the total protein content of the protein composition as 100%, the protein composition contains about 32.0% alpha-lactalbumin and about 32.0% beta-casein, or, the protein composition contains about 29.0% alpha-lactalbumin and about 32.0% beta-casein, or, the protein composition contains about 21.5% alpha-lactalbumin and about 29.0% beta-casein, or, the protein composition contains about 21.0% alpha-lactalbumin and about 26.0% beta-casein.

[0029] According to a specific embodiment of the present invention, preferably, based on the total protein content of the protein composition as 100%, the content of whey protein in the protein composition is about 30.0% or more, for example, 35.0%-90.0%, preferably about 35.0%-70.0%, more preferably about 40.0%-70.0%, and further preferably about 55.0%-65.0%.

[0030] According to a specific embodiment of the present invention, preferably, based on the total protein content of the protein composition as 100%, the casein content in the protein composition is controlled to be above about 10.0%, for example, 10.0%-65.0%, preferably about 30.0%-65.0%, more preferably about 30.0%-60.0%, and further preferably about 35.0%-45.0%.

[0031] According to a specific embodiment of the present invention, the content of whey protein and the content of casein in the protein composition can be controlled simultaneously. Preferably, the content of whey protein in the protein composition is controlled to be about 35.0%-70.0%, and the content of casein is controlled to be about 30.0%-65.0%, for example, 60.0% and 40.0%, 35.0% and 65.0%, 50.0% and 50.0%, or 70.0% and 30.0%.

[0032] According to a specific embodiment of the present invention, preferably, the above-mentioned protein composition is prepared from one or more raw materials including liquid milk, milk powder, whey protein powder, and casein powder. The above-mentioned raw materials can also be derived from whey powder, lactoferrin, hydrolyzed protein, etc.; liquid milk includes whole milk and / or skim milk; the raw materials of the protein composition can also contain lactose. Among them, milk powder preferably includes whole milk powder (or whole milk powder) and / or skim milk powder (or skim milk powder); the whey protein powder preferably includes concentrated whey protein powder with different protein contents and whey protein powder with different α-lactalbumin contents; the casein powder preferably includes casein powder with different β-casein contents. Among them, milk powder, whey protein powder, and casein powder are used as sources of protein, and their addition amounts are to meet the content range requirements of whey protein and the content range requirements of casein. Whey protein powder and casein powder are used as sources of α-lactalbumin and β-casein, respectively, and their respective addition amounts are to meet the respective contents of α-lactalbumin and β-casein.

[0033] It should be noted that the protein composition of the present invention can be prepared by pre-mixing various raw materials to obtain a composition, which is then added to food as a single component, or various raw materials constituting the protein composition can be added to food separately.

[0034] According to a specific embodiment of the present invention, the protein composition of the present invention can be obtained by mixing various raw materials. Specifically, the preparation method of the protein composition of the present invention comprises mixing at least one of the following protein powders and / or milk powders:

[0035] (1) Whey protein powder with an α-lactalbumin content of 25% to 55% can be called a whey protein powder with a low α-lactalbumin content;

[0036] (2) Whey protein powder with an α-lactalbumin content of 75%-95% can be called whey protein powder with a high α-lactalbumin content;

[0037] (3) Whey protein powder with a β-casein content of 35%-70% can be called low β-casein whey protein powder;

[0038] (4) Whey protein powder with a β-casein content of 40%-80% can be called high β-casein whey protein powder;

[0039] (5) Whey protein powder with a protein content of 60%-95%;

[0040] (6) Milk powder with a protein content of 15%-50% (preferably skimmed milk powder).

[0041] According to a specific embodiment of the present invention, preferably, the α-lactalbumin content of the whey protein powder (1) with low α-lactalbumin content used in the preparation process is 30%-50%, more preferably 35%-45%, and further preferably 38%-42%.

[0042] According to a specific embodiment of the present invention, preferably, the α-lactalbumin content of the whey protein powder (2) with a high α-lactalbumin content used in the preparation process is 80%-95%, more preferably 85%-95%, and further preferably 90%-95%.

[0043] According to a specific embodiment of the present invention, preferably, the β-casein content of the whey protein powder (3) with low β-casein content used in the preparation process is 40%-65%, more preferably 45%-60%, and further preferably 50%-55%.

[0044] According to a specific embodiment of the present invention, preferably, the β-casein content of the whey protein powder (4) with a high β-casein content used in the preparation process is 45%-80%, more preferably 50%-75%, further preferably 55%-70%, and further preferably 60%-65%.

[0045] According to a specific embodiment of the present invention, preferably, the protein content of the whey protein powder (5) used in the preparation process is 65%-90%, more preferably 70%-85%, and further preferably 75%-80%.

[0046] According to a specific embodiment of the present invention, preferably, the protein content of the milk powder (6) used in the preparation process is 20%-45%, more preferably 25%-40%, and further preferably 30%-35%.

[0047] According to a specific embodiment of the present invention, the specific content ranges of the above-listed whey protein powder with low α-lactalbumin content (1), whey protein powder with high α-lactalbumin content (2), whey protein powder with low β-casein content (3), whey protein powder with high β-casein content (4), whey protein powder (5), and milk powder (6) can be used in any combination and are not limited to the combinations specifically listed above.

[0048] According to a specific embodiment of the present invention, preferably, the method for preparing the above-mentioned protein composition comprises mixing at least one of the following protein powders and / or milk powders:

[0049] Whey protein powder with a 41% alpha-lactalbumin content, such as that from Arla, Denmark;

[0050] Whey protein powder with an alpha-lactalbumin content of 92.3%, such as that from Angop;

[0051] Whey protein powder with a 53% beta-casein content, such as that from Kerry, Ireland;

[0052] Whey protein powder with a 63.2% beta-casein content, such as Arla's product from Denmark;

[0053] Whey protein concentrate (WPC80) with 80% protein content, such as that from Wheyco of Germany;

[0054] Skimmed milk powder with a protein content of 33.5%, such as Fonterra's product.

[0055] The present invention also provides a food containing the above-mentioned protein composition provided by the present invention to improve the digestibility of the protein contained therein, and, based on the total protein content of the food being 100%, the food contains about 10.5%-51.0% of α-lactalbumin and about 10.0%-40.0% of β-casein.

[0056] According to a specific embodiment of the present invention, preferably, based on 100% of the total protein content of the food, the food contains about 15.0%-51.0% of α-lactalbumin.

[0057] According to a specific embodiment of the present invention, preferably, based on the total protein content of the food being 100%, the food contains about 12.0%-40.0% β-casein, more preferably about 15.0%-40.0%, and even more preferably about 20.0%-32.0%.

[0058] According to a specific embodiment of the present invention, preferably, based on 100% of the total protein content of the food, the food contains about 21.0%-32.0% of α-lactalbumin and about 26.0%-32.0% of β-casein.

[0059] According to a specific embodiment of the present invention, preferably, the whey protein content in the food is about 30.0% or more, for example, 35.0%-90.0%, preferably about 35.0%-70.0%, more preferably about 40.0%-70.0%, and further preferably about 55.0%-65.0%, and the above contents are all calculated based on the total protein content in the food as 100%.

[0060] According to a specific embodiment of the present invention, preferably, the casein content in the food is about 10.0% or more, such as 10.0%-65.0%, preferably about 30.0%-65.0%, more preferably about 30.0%-60.0%, and further preferably about 35.0%-45.0%.

[0061] According to a specific embodiment of the present invention, preferably, the content of whey protein and the content of casein in the food can be controlled simultaneously. Preferably, the content of whey protein in the food is controlled to be about 35.0%-70.0%, and the content of casein is controlled to be about 30.0%-65.0%, for example, 60.0% and 40.0%, 35.0% and 65.0%, 50.0% and 50.0%, or 70.0% and 30.0%.

[0062] According to a specific embodiment of the present invention, preferably, the total protein content of the food is about 10.20-16.10g / 100g, such as 10.20g / 100g, 10.50g / 100g, 11.00g / 100g, 12.00g / 100g, 13.00g / 100g, 14.00g / 100g, 15.00g / 100g, 15.80g / 100g, 16.10g / 100g, and the total protein content can also be a range consisting of the above specific contents as endpoints, such as 10.20-15.80g / 100g, 1 0.20-15.00g / 100g, 10.20-14.00g / 100g, 10.20-13.00g / 100g, 10.20-12.00g / 100g, 10.20-11.00g / 100g, 10.20-10.50g / 100g, 10.50-16.10g / 100g, 10.50-15.80g / 100g, 10.50-15.00g / 100g, 10.50-14.00g / 100g, 10.50-13.00g / 100g, 10.50- 12.00g / 100g, 10.50-11.00g / 100g, 11.00-16.10g / 100g, 11.00-15.80g / 100g, 11.00-15.00g / 100g, 11.00-14.00g / 100g , 11.00-13.00g / 100g, 11.00-12.00g / 100g, 12.00-16.10g / 100g, 12.00-15.80g / 100g, 12.00-15.00g / 100g, 12.00-14.00 g / 100g, 12.00-13.00g / 100g, 13.00-16.10g / 100g, 13.00-15.80g / 100g, 13.00-15.00g / 100g, 13.00-14.00g / 100g, 14.00 -16.10g / 100g, 14.00-15.80g / 100g, 14.00-15.00g / 100g, 15.00-16.10g / 100g, 15.00-15.80g / 100g, 15.80-16.10g / 100g wait.

[0063] According to a specific embodiment of the present invention, preferably, the content of α-lactalbumin in the food is about 1.50-5.30 g / 100 g, and the content of β-casein is about 2.00-5.20 g / 100 g.

[0064] According to a specific embodiment of the present invention, the food may contain different amounts of α-lactalbumin and β-casein, wherein:

[0065] The content of α-lactalbumin can be 1.50g / 100g, 2.00g / 100g, 2.20g / 100g, 2.40g / 100g, 3.00g / 100g, 3.30g / 100g, 4.00g / 100g, 4.60g / 100g, 5.00g / 100g, 5.30g / 100g; the content of α-lactalbumin can also be a range with the above specific contents as endpoints, for example, 1.50-2.00g / 100g, 1.50-2.20g / 100g, 1.50-2.40g / 100g, 1.50-3.00g / 100g, 1.50-3.30g / 100g, 1.50-4.00g / 100g, 1.50-4.60g / 100g, 1.50-5.00g / 100g, 1.50-5.30g / 100g, 2.00- 2.20g / 100g, 2.00-2.40g / 100g, 2.00-3.00g / 100g, 2.00-3.30g / 100g, 2.00-4.00g / 100g, 2.00-4.60g / 100g, 2.00-5.00g / 100g, 2.00-5.30g / 100g, 2.20-2.40g / 100g, 2.20-3.00g / 100g, 2.20-3.30g / 100g, 2.20-4.00g / 100g, 2.20-4.60g / 100g, 2.20-5.00g / 100g, 2.20-5.30g / 100g, 2.40-3.00g / 100g, 2.40-3.30g / 100g, 2.40-4.00g / 100g, 2.40-4.60g / 100g, 2.40-5 .00g / 100g, 2.40-5.30g / 100g, 3.00-3.30g / 100g, 3.00-4.00g / 100g, 3.30-4.60g / 100g, 3.30-5.00g / 100g, 3.30-5.30g / 100g, 4.00-4.60g / 100g, 4.00-5.00g / 100g, 4.00-5.30g / 100g, 4.60-5.00g / 100g, 4.60-5.30g / 100g, 5.00-5.30g / 100g, etc.;

[0066] The content of β-casein can be 2.00g / 100g, 2.50g / 100g, 3.00g / 100g, 3.50g / 100g, 4.00g / 100g, 4.50g / 100g, 5.00g / 100g, 5.20g / 100g; the content of β-casein can also be a range with the above specific content as the endpoint combination, such as 2.00-2.50g / 100g, 2 .00-3.00g / 100g, 2.00-3.50g / 100g, 2.00-4.00g / 100g, 2.00-4.50g / 100g, 2.00-5.00 g / 100g, 2.00-5.20g / 100g, 2.50-3.00g / 100g, 2.50-3.50g / 100g, 2.50-4.00g / 100g, 2 .50-4.50g / 100g, 2.50-5.00g / 100g, 2.50-5.20g / 100g, 3.00-3.50g / 100g, 3.00-4.00 g / 100g, 3.00-4.50g / 100g, 3.00-5.00g / 100g, 3.00-5.20g / 100g, 3.50-4.00g / 100g, 3 .50-4.50g / 100g, 3.50-5.00g / 100g, 3.50-5.20g / 100g, 4.00-4.50g / 100g, 4.00-5.00g / 100g, 4.00-5.20g / 100g, 4.50-5.00g / 100g, 4.50-5.20g / 100g, 5.00-5.20g / 100g, etc.

[0067] The contents of the above-mentioned α-lactalbumin and β-casein can be combined or other specific combinations, for example: the content of α-lactalbumin is 2.38g / 100g, and the content of β-casein is 3.20g / 100g; or, the content of α-lactalbumin is 3.343g / 100g, and the content of β-casein is 4.13g / 100g; or, the content of α-lactalbumin is 3.43g / 100g , the content of β-casein is 4.61g / 100g; or, the content of α-lactalbumin is 4.642g / 100g, and the content of β-casein is 5.122g / 100g; or, the content of α-lactalbumin is 5.117g / 100g, and the content of β-casein is 5.127g / 100g; or, the content of α-lactalbumin is 1.795g / 100g, and the content of β-casein is The content of α-lactalbumin is 2.386g / 100g; or, the content of α-lactalbumin is 2.224g / 100g and the content of β-casein is 3.036g / 100g; or, the content of α-lactalbumin is 1.572g / 100g and the content of β-casein is 2.102g / 100g; or, the content of α-lactalbumin is 2.208g / 100g and the content of β-casein is 3.027g / 100g. g / 100g; or, the content of α-lactalbumin is 3.355g / 100g, and the content of β-casein is 3.363g / 100g; or, the content of α-lactalbumin is 1.585g / 100g, and the content of β-casein is 2.097g / 100g; or, the content of α-lactalbumin is 5.264g / 100g, and the content of β-casein is 2.108g / 100g, etc.

[0068] According to a specific embodiment of the present invention, the food can be adult food, children's food or infant food based on the applicable population; and can be milk powder or liquid milk, such as adult milk powder, children's milk powder, infant formula milk powder, etc. based on the type.

[0069] According to a specific embodiment of the present invention, in the above-mentioned method for improving the digestibility of protein in food, protein composition or food, based on the total protein content as 100%, the contents of α-lactalbumin and β-casein can be controlled in different ranges, wherein the content range of α-lactalbumin is c%-51.0%, and the content range of β-casein is d%-40.0%. In addition, the content ranges of α-lactalbumin and β-casein can be selected separately or in combination (i.e., the content range of α-lactalbumin is c%-51.0%, and the content range of β-casein is d%-40.0%). a%-51.0%, and at the same time, the content range of β-casein is b%-40.0%), wherein c is any value between 10.5-51.0, preferably an integer, that is, the content range of α-lactalbumin can be 11.0%-51.0%, 13.0%-51.0%, 15.0%-51.0%, 17.0%-51.0%, 19.0%-51.0%, 21.0%-51.0%, 23.0%-51.0%, 25.0%-51.0%, 27.0%-51.0%, 28.0%-51.0%, 29.0%-51.0%, 30.0%-51.0%, 31.0%-32.0%, 33.0%-33.0%, 34.0%-35.0%, 36.0%-37.0%, 38.0%-39.0%, 39.0%-39.0%, 40.0%-41.0%, 41.0%-42.0%, 43.0%-43.0%, 44.0%-45.0%, 46.0%-47.0%, 48.0%-49.0%, 49.0%-50.0%, 50.0%-51.0%, 51.0%-51.0%, 52.0%-51.0%, 53.0%-51.0%, 54.0%-51.0%, 55.0%-51.0%, 56.0%-51.0%, 57.0%-51.0%, 58.0%-51.0%, 59.0%-51.0%, 60.0%-61.0%, 61.0%-61 1.0%, 29.0%-51.0%, 31.0%-51.0%, 33.0%-51.0%, 35.0%-51.0%, 37.0%-51.0%, 39.0%-51.0%, 41.0%-51.0%, 43.0%-51.0%, 45.0%-51.0%, 47.0%-51.0%, 49.0%-51.0%, etc.; d is any value between 10.0-40.0, preferably an integer, that is, the content of β-casein can range from 11 .0%-40.0%, 13.0%-40.0%, 15.0%-40.0%, 17.0%-40.0%, 19.0%-40.0%, 21.0%-40.0%, 23.0%-40.0%, 25.0%-40.0%, 27.0%-40.0%, 29.0%-40.0%, 31.0%-40.0%, 33.0%-40.0%, 35.0%-40.0%, 37.0%-40.0%, 39.0%-40.0%, etc.The above-mentioned content ranges of α-lactalbumin and β-casein can be combined or included in the numerical range within the above-mentioned ranges, for example: based on the total protein content of the food / protein composition as 100%, the food / protein composition contains 15.0%-32.0% α-lactalbumin and 26.0%-32.0% β-casein, or the food / protein composition contains 15.0%-32.0% α-lactalbumin and 29.0%-32.0% β-casein, or The food / protein composition contains 16.0% to 32.0% alpha-lactalbumin and 20.0% to 32.0% beta-casein, or the food / protein composition contains 16.0% to 32.0% alpha-lactalbumin and 26.0% to 32.0% beta-casein, or the protein composition contains 16.0% to 32.0% alpha-lactalbumin and 29.0% to 32.0% beta-casein, or the food / protein composition contains 21.0% -32.0% α-lactalbumin and 20.0%-32.0% β-casein, or the food / protein composition contains 21.0%-32.0% α-lactalbumin and 26.0%-32.0% β-casein, or the food / protein composition contains 21.0%-32.0% α-lactalbumin and 29.0%-32.0% β-casein, or the food / protein composition contains 29.0%-32.0% α-lactalbumin and 26.0%-32.0% β-casein, The food / protein composition contains 20.0%-32.0% β-casein, or the food / protein composition contains 29.0%-32.0% α-lactalbumin and 26.0%-32.0% β-casein, or the food / protein composition contains 29.0%-32.0% α-lactalbumin and 29.0%-32.0% β-casein, or the food / protein composition contains 29.0%-32.0% α-lactalbumin and 32.0% β-casein. In addition to α-lactalbumin and β-casein, the above-mentioned food / protein composition also contains other types of protein.

[0070] According to a specific embodiment of the present invention, in the above-mentioned method for improving protein digestibility in food, protein composition, or food, the content of whey protein and casein can be controlled within different ranges, based on the total protein content as 100%. Preferably, the content of whey protein in the food / protein composition is controlled to be 55.0%-90.0%, and the content of casein is controlled to be 10.0%-45.0%; more preferably, the content of whey protein in the food / protein composition is controlled to be 55.0%-80.0%, and the content of casein is controlled to be 20.0%-45.0%; further preferably, the content of whey protein in the food / protein composition is controlled to be 55.0%-70.0%, and the content of casein is controlled to be 30.0%-45.0%; further preferably, the content of whey protein in the food / protein composition is controlled to be 55.0%-65.0%, and the content of casein is controlled to be 35.0%-45.0%. The sum of the content of whey protein and casein is not required to be 100%.

[0071] The technical solution of the present invention has the following beneficial effects:

[0072] (1) The technical solution of the present invention can significantly improve the digestibility of whey protein in food, especially infant formula. (2) The technical solution of the present invention can release more types of free amino acids. (3) The technical solution of the present invention can increase the release ratio of essential amino acids EAA. (4) The technical solution of the present invention can produce more small molecule peptides during the digestion process. (5) The technical solution of the present invention can produce more characteristic peptide segments. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] 1 to 6 respectively show the results of releasing small molecule peptides from the samples of the protein compositions of Examples 1 to 5 and Comparative Example 1 in an in vitro gastric digestion experiment. DETAILED DESCRIPTION

[0074] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0075] Description of raw materials for Examples and Comparative Examples:

[0076] The skimmed milk powder is produced by Fonterra Group and has a protein content of 33.5%.

[0077] WPC80 is a concentrated whey protein powder with a protein content of 80%, purchased from Wheyco, Germany.

[0078] The whey protein powder with low α-lactalbumin content had an α-lactalbumin content of 41% and was purchased from Arla Corporation of Denmark.

[0079] The whey protein powder with high α-lactalbumin content has an α-lactalbumin content of 92.3% and is purchased from Angrapur Company of the United States.

[0080] The whey protein powder with low β-casein content had a β-casein content of 53% and was purchased from Kerry, Ireland.

[0081] The whey protein powder with high β-casein content had a β-casein content of 63.2% and was purchased from Arla Corporation of Denmark.

[0082] Lactose was purchased from Glanbia, USA.

[0083] Example 1

[0084] This example provides a protein composition (sample 1), the raw materials of which include (in parts by weight):

[0085]

[0086] The protein composition provided in this embodiment has a whey protein content of 60% and a casein content of 40% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0087] Example 2

[0088] This example provides a protein composition (Sample 2), the raw materials of which include (in parts by weight):

[0089]

[0090] The protein composition provided in this embodiment has a whey protein content of 60% and a casein content of 40% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0091] Example 3

[0092] This example provides a protein composition (Sample 3), the raw materials of which include (in parts by weight):

[0093]

[0094] The protein composition provided in this embodiment has a whey protein content of 60% and a casein content of 40% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0095] Example 4

[0096] This example provides a protein composition (Sample 4), the raw materials of which include (in parts by weight):

[0097]

[0098] The protein composition provided in this embodiment has a whey protein content of 60% and a casein content of 40% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0099] Example 5

[0100] This example provides a protein composition (Sample 5), the raw materials of which include (in parts by weight):

[0101]

[0102]

[0103] The protein composition provided in this embodiment has a whey protein content of 60% and a casein content of 40% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0104] Comparative Example 1

[0105] This comparative example provides a protein composition (sample 6), the raw materials of which include (in parts by weight):

[0106] 160 servings of skimmed milk powder

[0107] WPC80 70 parts

[0108] Lactose 450 parts.

[0109] The protein composition provided in this comparative example has a whey protein content of 60% and a casein content of 40% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, the content and proportion of β-casein, etc. are shown in Table 1.

[0110] Example 6

[0111] This example provides a protein composition (Sample 7), the raw materials of which include (in parts by weight):

[0112] 230 servings of skimmed milk powder

[0113] 16.5 servings of whey protein powder with high α-lactalbumin content

[0114] 300 parts of lactose.

[0115] The protein composition provided in this embodiment has a whey protein content of 35% and a casein content of 65% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0116] Example 7

[0117] This example provides a protein composition (Sample 8), the raw materials of which include (in parts by weight):

[0118]

[0119] The protein composition provided in this embodiment has a whey protein content of 35% and a casein content of 65% (based on the total protein content being 100%). The total protein content, the content and proportion of α-lactalbumin, the content and proportion of β-casein, etc. are shown in Table 1.

[0120] Comparative Example 2

[0121] This comparative example provides a protein composition (sample 9), the components of which include (in parts by weight):

[0122] 262 parts skim milk powder

[0123] WPC80 26 parts

[0124] Lactose 383.5 parts.

[0125] The protein composition provided in this comparative example has a whey protein content of 35% and a casein content of 65% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, the content and proportion of β-casein, etc. are shown in Table 1.

[0126] Example 8

[0127] This example provides a protein composition (sample 10), the raw materials of which include (in parts by weight):

[0128]

[0129] The protein composition provided in this embodiment has a whey protein content of 50% and a casein content of 50% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0130] Example 9

[0131] This example provides a protein composition (sample 11), the raw materials of which include (in parts by weight):

[0132]

[0133] The protein composition provided in this embodiment has a whey protein content of 50% and a casein content of 50% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0134] Example 10

[0135] This example provides a protein composition (sample 12), the raw materials of which include (in parts by weight):

[0136]

[0137] The protein composition provided in this embodiment has a whey protein content of 50% and a casein content of 50% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0138] Comparative Example 3

[0139] This comparative example provides a protein composition (sample 13), the raw materials of which include (in parts by weight):

[0140] 202 parts skim milk powder

[0141] WPC80 52 parts

[0142] Lactose 418 parts.

[0143] The protein composition provided in this comparative example has a whey protein content of 50% and a casein content of 50% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, the content and proportion of β-casein, etc. are shown in Table 1.

[0144] Example 11

[0145] This example provides a protein composition (sample 14), the raw materials of which include (in parts by weight):

[0146]

[0147] The protein composition provided in this embodiment has a whey protein content of 70% and a casein content of 30% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0148] Example 12

[0149] This example provides a protein composition (sample 15), the raw materials of which include (in parts by weight):

[0150]

[0151] The protein composition provided in this embodiment has a whey protein content of 70% and a casein content of 30% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, and the content and proportion of β-casein are shown in Table 1.

[0152] Comparative Example 4

[0153] This comparative example provides a protein composition (sample 16), the raw materials of which include (in parts by weight):

[0154] 121 parts skim milk powder

[0155] WPC80 86.5 parts

[0156] Lactose 525 parts.

[0157] The protein composition provided in this comparative example has a whey protein content of 70% and a casein content of 30% (based on the total protein content of 100%). The total protein content, the content and proportion of α-lactalbumin, the content and proportion of β-casein, etc. are shown in Table 1.

[0158] Example 13

[0159] This embodiment provides an infant formula milk powder containing a composition of α-lactalbumin and β-casein protein;

[0160] The infant formula milk powder comprises, by weight, 120 parts of raw cow's milk; 6 parts of whey protein powder; 30 parts of lactose; 23 parts of edible vegetable blending oil, including 13.8 parts of OPO structured fat; 4 parts of α-lactalbumin powder; 4 parts of casein; 4 parts of galacto-oligosaccharide; 2 parts of fructo-oligosaccharide; 1.2 parts of minerals; 0.35 parts of complex vitamins; 0.15 parts of choline chloride; 1.5 parts of docosahexaenoic acid; and 1.6 parts of arachidonic acid. Based on the total protein content of the formula milk powder being 100%, the content of α-lactalbumin is 18%, and the content of β-casein is 22%.

[0161] Example 14

[0162] This embodiment provides a formula milk powder for pregnant women containing a composition of α-lactalbumin and β-casein protein;

[0163] The formula milk powder comprises, by weight, 6 parts of skim milk powder; 3 parts of whey protein powder (WPC 80); 50 parts of lactose; 26 parts of edible vegetable blending oil; 5 parts of α-lactalbumin powder; 3 parts of casein; 4 parts of galacto-oligosaccharide; 2 parts of fructo-oligosaccharide; 12 parts of minerals; 0.35 parts of complex vitamins; 0.15 parts of choline chloride; 1 part of docosahexaenoic acid; and 0.16 parts of arachidonic acid. Taking the total protein content of the formula milk powder as 100%, the content of α-lactalbumin is 21%, and the content of β-casein is 26%.

[0164] Table 1

[0165]

[0166]

[0167] The following in vitro simulation of the digestion process in the stomach and small intestine of infants was used to evaluate the protein digestion of the samples provided in Examples 1-12 and Comparative Examples 1-4, including the degradation of whey protein in the stomach, the release of amino acids after digestion in the small intestine, and the production of peptides.

[0168] 1. In vitro gastric digestion experiments

[0169] 1. Sample Preparation and Processing

[0170] The method for the in vitro simulated gastric digestion experiment of the samples was based on the Dupont method with some modifications as follows:

[0171] (1) Preparation of milk sample: According to the protein content determination results, the sample concentration was adjusted to 10 mg / mL with deionized water to prepare 50 mL of milk sample, and then 1 mol / L HCl was added to adjust the pH value to 4.0, and preheated in a 37°C water bath.

[0172] (2) Preparation of simulated gastric fluid: Weigh 4.33 mg of pepsin and 23.755 mg of gastric lipase, add 45 mL of 0.15 M NaCl solution, adjust the pH to 4.0 with 1 M hydrochloric acid, and dilute to 50 mL to form simulated gastric fluid. The final concentration of pepsin in the system is 113.75 U / mL, and the final concentration of gastric lipase is 21 U / mL.

[0173] (3) Gastric digestion experiment process: 50 mL of milk sample was added to 50 mL of simulated gastric fluid in an enzyme reactor (37°C). Samples were taken at 0 h and 3 h of digestion, with 20 mL sample taken each time. The pH of the sample was adjusted to 7.0 with 1 M NaOH to terminate the reaction.

[0174] The samples of Examples 1-12 and Comparative Examples 1-4 were pre-treated in the above manner to obtain gastric digestive fluid samples at different digestion times.

[0175] 2. Semi-quantitative Analysis of Digestive Fluids

[0176] (1)SDS-PAGE:

[0177] The samples obtained at 0 h and 3 h were diluted with deionized water at a ratio of 1:1, mixed with 2× sample buffer (premixed protein sample buffer from Bio-rad) at a ratio of 1:1, and then heated to boil. The sample volume was 5 μL.

[0178] The following electrophoresis and staining methods were used:

[0179] The concentration of the separating gel was 12% (w / v), and the stacking gel was 5% (w / v). The specific formula is shown in Table 2. The electrophoresis process was performed at a constant voltage of 150 V for the stacking gel and 300 V for the separating gel. The stain was a 0.1% Coomassie Brilliant Blue R-250 solution, and the decolorizer was a mixed solution of ethanol and acetic acid. After the gel run was completed, the gel was gently removed, the electrophoresis buffer was rinsed off, and the gel was stained with Coomassie Brilliant Blue solution on a horizontal shaker for 2 h, followed by decolorization with a decolorizer until the bands were clearly visible.

[0180] Table 2 Gel composition of SDS-PAGE

[0181] Components: 12% separating gel (mL), 5% stacking gel (mL), distilled water 10.25.8, 30% Acr-Bis (29:1) 12.01.7, separating gel buffer (4X) 7.5, stacking gel buffer (4X) -2.5, 10% gel polymerization catalyst 0.30.1, TEMED 0.0120.01

[0182] (2) Semi-quantitative analysis of protein content changes: Tanon Image electrophoresis image processing software was used to perform a semi-quantitative analysis of the trend of changes in the relative content of milk protein on the electrophoretic bands of the gastric digestive fluid samples of Examples 1-5 and Comparative Example 1. The relative content of whey protein at 0 min was set as 100%, and the relative protein content at other time points was the ratio of the band area at that time point to that at 0 min.

[0183] 2. In vitro gastric and intestinal digestion experiments

[0184] 1. Sample Preparation and Processing

[0185] (1) Preparation of milk sample: Adjust the sample concentration to 10 mg / mL with deionized water to prepare 50 ml of milk sample, then add 1 mol / L HCl to adjust the pH to 4.0, and preheat in a 37°C water bath.

[0186] (2) Preparation of simulated gastric fluid: Weigh 4.33 mg of pepsin and 23.755 mg of gastric lipase, add 45 mL of 0.15 M NaCl solution, adjust the pH to 4.0 with 1 M hydrochloric acid, and dilute to 50 mL to form simulated gastric fluid. The final concentration of pepsin in the system is 113.75 U / mL, and the final concentration of gastric lipase is 21 U / mL.

[0187] (3) Preparation of simulated intestinal fluid: Weigh 0.324 mg of trypsin, 0.988 mg of chymotrypsin, 2.27 g of pancreatic lipase, and 0.66 g of bile salts, add 245 mL of 0.15 M NaCl solution, adjust the pH to 6.5 with 1 M NaOH, and dilute to 250 mL to prepare simulated intestinal fluid.

[0188] (4) Gastrointestinal digestion experimental process: 25 mL of milk sample was added to 25 mL of simulated gastric fluid in an enzyme reactor (37°C) for 2 h of gastric digestion, and then digested in simulated intestinal fluid. Samples were taken at 0 h, 2 h in the stomach, 0.25 h in the intestine, 1 h in the intestine, and 2 h in the intestine, respectively. 20 mL was sampled each time. The reaction was terminated with an enzyme preparation to obtain different digestive fluid samples. Taking "1 h in the intestine" as an example, it means that the sample was digested in simulated gastric fluid for 2 h and then digested in simulated intestinal fluid for another 1 h.

[0189] 2. Determination of free amino acids

[0190] Take 1 mL of digestion sample at each time point and dilute it with an equal volume of 10g / 100mL TCA, shake well, sonicate for 30 minutes, and let it stand for more than 2 hours; centrifuge the sample at 10,000 rpm for 30 minutes; take the supernatant and pass it through a 0.45μm membrane, and then take 400μL of the supernatant and put it into a liquid phase vial.

[0191] The amino acid content of the samples was analyzed by HPLC using a high-performance liquid chromatography system equipped with a sodium cation exchange amino acid analysis column (4×150 mm, Pickering, USA) and a phthaloyl post-column derivatization system (Pickering, USA).

[0192] Chromatographic conditions: Angilent Hypersil ODS column (5 μm, 4.0 mm × 250 mm); column temperature, 40°C; mobile phase A (pH = 7.2): 27.6 mmol / L sodium acetate-triethylamine-tetrahydrofuran (volume ratio of 500:0.11:2.5), mobile phase B (pH = 7.2): 80.9 mmol / L sodium acetate-methanol-acetonitrile (volume ratio of 1:2:2); gradient elution was used, and the elution program was: 0 min, 8% B; 17 min, 50% B; 20.1 min, 100% B; 24.0 min, 0% B; mobile phase flow rate, 1.0 mL / min; ultraviolet detector (VWD) detection wavelength was 338 nm, and proline was detected at 262 nm; amino acid content was quantified by external standard method.

[0193] 3. Determination of Peptide Fragments after Digestion

[0194] The ultrafiltration tube was first centrifuged at 5000g for 20 minutes with PBS buffer, and this step was repeated three times to achieve the purpose of cleaning; the collection tube was replaced, the sample was loaded into the ultrafiltration tube, and the sample was centrifuged at 5000g for 20 minutes to collect the flow-through; the ultrafiltration tube was then washed with 2-3mL of PBS buffer and combined with the flow-through in the third step and then dried; the peptide fragments after drying were desalted using a suitable desalting column, and the obtained sample was collected using Orbitrap Fusion TM Tribrid TMDetection was performed using a three-in-one mass spectrometer.

[0195] (1) HPLC: The dried peptide samples were reconstituted with mobile phase A (2% ACN, 0.1% FA), centrifuged at 20,000 g for 10 minutes, and the supernatant was injected. Separation was performed using a Thermo Fisher Scientific UltiMate 3000 UHPLC. The sample was first enriched and desalted on a trap column, then connected in series with a self-assembled C18 column (75 μm inner diameter, 3 μm column material > particle size, 25 cm column length) and separated at a flow rate of 300 nl / min using the following effective gradient: 0-5 min, 5% mobile phase B (98% ACN, 0.1% FA); 5-45 min, mobile phase B linearly increased from 5% to 25%; 45-50 min, mobile phase B increased from 25% to 35%; 50-52 min, mobile phase B increased from 35% to 80%; 52-54 min, 80% mobile phase B; 54-60 min, 5% mobile phase B. The end of the nanoliter liquid phase separation is directly connected to the mass spectrometer.

[0196] (2) Mass spectrometry detection: The peptides separated by liquid phase were ionized by nanoESI source and then entered into tandem mass spectrometer Q-Exactive HF X (Thermo Fisher Scientific, San Jose, CA) for DDA (data-dependent acquisition) mode detection. The main parameter settings were: ion source voltage was set to 2 kV; primary mass spectrometry scanning range was 350-1500 m / z; resolution was set to 60,000; secondary mass spectrometry starting m / z was fixed at 100; resolution was 15,000. The screening conditions for the parent ion of secondary fragmentation were: charge 2+ to 6+, peak intensity greater than 10,000 and ranked in the top 30 parent ions. The ion fragmentation mode was HCD, and the fragment ions were detected in the Orbitrap. The dynamic exclusion time was set to 30 s. The AGC settings were: primary 3E6, secondary 1E5.

[0197] (3) Data Information Analysis The data from the machine were identified using the Andromeda engine integrated with MaxQuant. MaxQuant then performed quantitative analysis based on the peptide peak intensity, peak area, liquid chromatography retention time and other information related to the primary mass spectrometry, and carried out a series of statistical analysis and quality control. Filtering was completed at the spectrum level with PSM-level FDR <= 1%, and further filtering was performed at the peptide level with Peptide-level FDR <= 1% to obtain significant identification results. Then, based on the identification results, GO, COG, and Pathway functional annotations were performed on the precursor protein. Based on the quantitative results, the differential peptides between different comparison groups were calculated, and finally, the precursor proteins corresponding to the differentially enriched peptides were functionally analyzed.

[0198] Experimental results and analysis:

[0199] 1. Whey protein digestibility

[0200] The whey protein digestibility data of the samples of Examples 1-7, 9-10, 12 and Comparative Examples 1-4 in the in vitro gastric digestion experiment are shown in Table 3 and FIG1 .

[0201] Table 3

[0202]

[0203]

[0204] As can be seen from Table 3, during the in vitro gastric digestion process, compared with the samples of Comparative Examples 1-4, the samples of Examples 1-7, 9-10, and 12 of the present invention had relatively low proportions of residual whey protein at different digestion time points. This indicates that the digestion of whey protein in the in vitro stomach of Samples 1-5, 7-8, 11-12, and 15 was increased, that is, the protein compositions of Examples 1-7, 9-10, and 12 had better whey protein digestion performance than Comparative Example 1, and the effect was particularly prominent in the samples corresponding to Examples 5 and 6.

[0205] 2. Free amino acids

[0206] The types of free amino acids released from the samples of the protein compositions of Examples 1-12 and Comparative Examples 1-4 in the in vitro gastric digestion experiment include Lys, Phe, Met, Trp, Thr, Ile, Leu, Val, His, Cys-s, Tyr, Asp, Glu, Ser, Gly, Arg, Ala, Pro, EAA, NEAA, TAA, etc., among which Lys, Phe, Met, Trp, Thr, Ile, Leu, Val, His, and EAA are essential amino acids.

[0207] 3. Free essential amino acids EAA

[0208] The experimental data of the free essential amino acid EAA released by the samples of Examples 1-12 and Comparative Examples 1-4 in the in vitro gastrointestinal digestion experiment, that is, the percentage of the free essential amino acid EAA in the total free amino acids, are shown in Table 4.

[0209] EAA% = free essential amino acids / total free amino acids × 100%

[0210] Increase of EAA% after digestion = (EAA% after digestion - EAA% before digestion) ÷ EAA% before digestion

[0211] Table 4

[0212]

[0213] As can be seen from the data in Table 4: In the digestive juice obtained by in vitro gastrointestinal digestion, compared with the corresponding Comparative Examples 1-4,

[0214] the multiple of the increase in the release of essential amino acids (EAA) after digestion of the protein compositions of Examples 1-12 is greater, indicating that the technical solution provided by the present invention can generate more beneficial essential amino acids during digestion.

[0215] 4. Small molecular peptides (short peptides)

[0216] The proportion data of small molecular peptides released by the samples of the protein compositions of Examples 1-5 and Comparative Example 1 in the in vitro gastrointestinal digestion experiment are shown in Table 5 and Figures 1-6. Among them, Figures 1-5 correspond to the samples of Examples 1-5 respectively, and Figure 6 corresponds to the sample of Comparative Example 1 as a control. Among them, n-0 represents the data when sample n is not digested, Gn-120 represents the data when sample n is digested in simulated gastric juice for 120 min, In-120 represents the data when sample n is first digested in simulated gastric juice for 120 min and then digested in simulated intestinal juice for 120 min, n is 1, 2, 3, 4, 5, 6, and sample n refers to sample 1, sample 2, sample 3, sample 4, sample 5, sample 6.

[0217] Table 5 (unit: increased percentage (%))

[0218] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Short peptide Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 0 < X ≤ 10 173.37 259.80 314.59 360.41 376.76 163.99

[0219] As can be seen from the data in Table 5 and the curves in Figures 1-6: After in vitro gastrointestinal digestion, the increase ratio of small molecular peptides (0 < X ≤ 10) in the samples of the protein compositions of Examples 1-5 is significantly higher than that of the control sample (sample 6 of Comparative Example 1). Generally, it is considered that the process of protein degradation and differentiation into small molecules in the digestive tract is a gradual process. The lower the molecular weight of the peptide segment, the more beneficial it is generally considered for absorption. From this point, it can also be proved that the protein compositions of Examples 1-5 have good digestive performance. In particular, the proportion of small peptide molecules in the samples corresponding to Examples 2-5 is significantly higher than that of Comparative Example 1, indicating that when the content of α-lactalbumin is controlled at 21%-32% and the content of β-casein is controlled at 26%-32%, excellent results can be obtained in the release of small molecular peptides.

[0220] 5. Characteristic peptide segments

[0221] Table 6 shows the data on the characteristic peptides released from the samples of the protein compositions of Examples 1-5 in the in vitro gastrointestinal digestion experiment.

[0222] Table 6

[0223] Example 1 Example 2 Example 3 Example 4 Example 5 Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 F.QINNKIW.C 2.05E+063.24E+064.75E+051.27E+077.57E+06A.IVENNESTEYGLF.Q 4.99E+062.19E+062.82E+067.76E+062.02E+06K.GYGGVS.L 2.37E+064.07E+065.64E+064.49E+065.80E+06K.FLDDDLTDD.I 1.14E+066.07E+054.66E+052.46E+061.19E+06V.MFPPQ.S 2.27E+0 86.24E+089.43E+089.62E+087.86E+08L.TQTPVVVPP.F1.17E+082.48E+ 083.39E+083.90E+083.49E+08L.VYPPFGPIP.N6.41E+071.32E+081.43E+ 081.36E+081.81E+08L.PQNIPPL.T1.18E+081.78E+081.90E+081.21E+0 81.29E+08Q.TLALPPQP.L1.58E+073.07E+074.38E+061.02E+088.58E+07

[0224] Casein is rapidly hydrolyzed in the stomach into polypeptide fragments, and more peptides are released in the small intestine. Peptides derived from α-lactalbumin and β-lactoglobulin have also been repeatedly reported to be found in the digestive tract. Further research has shown that these peptides released from milk proteins have important physiological functions, such as regulating immune function, lowering blood pressure, inhibiting bacteria, promoting mineral absorption, regulating blood sugar metabolism, regulating appetite, acting as opioid peptides with morphine-like functions, and anti-oxidation. According to reports by Alice et al., multiple peptides with different physiological functions have been found in human body fluids after consuming milk products, such as opioid peptides derived from β-casein, ACE inhibitory peptides, and ACE inhibitory peptides derived from α-lactalbumin. Karima et al. used LC-MS / MS analysis to show that 30 minutes, 90 minutes and 120 minutes after suckling pigs ingested milk formula, a large number of peptides derived from β-casein (positions 74-91) were detected in the jejunum and ileum, respectively. These peptides have immune regulation and blood pressure lowering functions; 30 minutes and 90 minutes after ingestion, peptides of 7-15 amino acids derived from β-lactoglobulin were detected in the jejunum, and large peptides derived from β-lactoglobulin were found in the ileum, containing 23 amino acids and 40 amino acids, respectively. These peptides are related to the proliferation of spleen cells and cytokine release, and are speculated to have immune regulation functions.

[0225] Studies on breast milk have revealed a large number of peptides, and more peptides are released as digestion progresses in the infant's digestive tract. In vitro digestion studies have shown that β-casein in breast milk is the primary source of functional peptides, with 305 peptides from this source detected in undigested breast milk, and the number of peptides rising to 646 after digestion. A similar phenomenon has been observed for α-lactalbumin, with no reports of peptides from this source found in undigested breast milk, but 58 peptides reported after digestion.

[0226] Comparison of the peptides produced after in vitro gastric digestion revealed that the protein composition samples of Examples 1-5 produced some characteristic peptides, which were not found in the control sample 6 (Comparative Example 1). Further analysis of the functions of these peptides showed that the characteristic peptides produced after digestion are believed to play the following physiological functions in vivo: anti-inflammatory response, resistance to invasion of external pathogens, signal transmission in the body, etc.

[0227] From the above experimental results, we can see that:

[0228] The samples of Examples 1-7, 9-10, and 12 of the present invention all had relatively low proportions of residual whey protein at different digestion time points. The protein compositions of these Examples have excellent whey protein digestibility, especially Examples 5 and 6.

[0229] Samples of the protein compositions of Examples 1-12 were able to release a variety of free amino acids in an in vitro gastric digestion experiment.

[0230] In particular, the protein compositions of Examples 1-12 were able to release a large amount of essential amino acids after digestion, and the increase multiples of EAA release were relatively large, indicating that the protein compositions of Examples 1-12 could produce more beneficial essential amino acids during digestion.

[0231] After in vitro gastrointestinal digestion, the increase ratio of small molecular peptides (0 < X ≤ 10) in the samples of the protein compositions of Examples 1-5 was significantly increased, which was significantly better than the control sample (Sample 6 of Comparative Example 1). From this point, it can also be proved that the protein compositions of Examples 1-5 had good digestion performance. In particular, the proportion of small molecular peptides in the samples corresponding to Examples 2-5 was significantly higher than that of Comparative Example 1, indicating that excellent results could be obtained in the release of small molecular peptides when the content of α-lactalbumin was controlled at 21%-32% and the content of β-casein was controlled at 26%-32%.

[0232] Samples of the protein compositions of Examples 1-5 were able to produce characteristic peptide segments during digestion, which were not found in Sample 6 (Comparative Example 1) used as a control. Further analysis of the functions of these peptide segments showed that the characteristic peptides produced after digestion were considered to play the following physiological functions in vivo: anti-inflammatory response, resistance to invasion by external pathogens, signal transduction in the body, etc.

Claims

DEPCT6827 / 09 / 25671. A method for enhancing the digestibility of dietary proteins comprising control of the alpha-lactalbumin content in the diet to 10.5% to 51.0% and control of the beta-casein content in the diet to 10.0% to 40.0% compared to 100% of the total dietary protein content.

2. A method under claim 1 comprising control of the alpha-lactalbumin content in the diet to 15.0% to 32.0%, and control of the beta-casein content in the diet to 20.0% to 32.0% compared to 100% of the total dietary protein content.

3. A method under claim 1 comprising...

1. A method based on Claim 1 that incorporates controlling the alpha-lactalbumin content in the diet to 21.0% to 32.0%, and controlling the beta-casein content in the diet to 26.0% to 32.0% compared to 100% of the total protein content in the diet.

2. A method based on Claim 1 that incorporates controlling the alpha-lactalbumin content in the diet to 21.0% to 32.0%, and controlling the beta-casein content in the diet to 29.0% to 32.0% compared to 100% of the total protein content in the diet.

3. A method based on Claim 1 that incorporates controlling the whey protein content in the diet to 55.0% to 65%.0%, and controlling the casein content in the feed to 35.0% to 45.0%; and controlling the alpha-lactalbumin content in the feed to 32.0% and the beta-casein content in the feed to 32.0%; or controlling the alpha-lactalbumin content in the feed to 29.0% and the beta-casein content in the feed to 32.0%; or controlling the alpha-lactalbumin content in the feed to 21.5% and the beta-casein content in the feed to 29.0%; or controlling the alpha-lactalbumin content in the feed to 21.0% and the beta-casein content in the feed to 26.0%. All of the above values ​​are relative to 100% of the total protein components in the diet.

6. Method according to claim 1, in which enhancement of digestibility for protein in a diet is achieved by one or more of: enhancing the digestibility of whey protein; increasing the number of types of free-release amino acids; increasing the proportion of essential amino acids (EAAs) released among free-release amino acids; enhancing the formation of small molecule peptides; and increasing the number of types of characteristic-forming peptides.

7. Protein components that comprise 21.0% to 32%.0% of alpha-lactalbumin and 26.0% to 32.0% of beta-casein compared to 100% of the total protein components in protein composition 8. Protein composition according to claim 7, which consists of 21.0% to 32.0% of alpha-lactalbumin and 29.0% to 32.0% of beta-casein compared to 100% of the total protein components in protein composition 9. Protein composition according to claim 8, which consists of 32.0% of alpha-lactalbumin and 32.0% of beta-casein or 29.0% of alpha-lactalbumin and 32.0% of beta-casein or 21.5% of alpha-lactalbumin and 29.0% of beta-casein or 21.0% of alpha-lactalbumin.

10. Protein composition under claim 7, which includes 55.0% to 65.0% whey protein and 35.0% to 45.0% casein, compared to 100% of the total protein components in protein composition 10. Food product which includes the protein composition under claim 7 and which includes 21.0% to 32.0% alpha-lactalbumin and 26.0% to 32.0% beta-casein, compared to 100% of the total protein components in the food product 11. Food product under claim 11, which includes 55.0% to 65.0%12. Food products under claim 11 where the total protein component in the food product is 10.20 to 16.10 g / 100g; 13. Food products under claim 11 where the alpha-lactalbumin component in the food product is 1.50 to 5.30 g / 100g and the beta-casein component in the food product is 2.00 to 5.20 g / 100g; 14. Food products under claim 11 where the food product is milk powder or liquid milk.