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Chapter 1. Introduction
1
1)
Scope and properties of Amino Acid Composition Tables
Scope
Protein is a polymer of amino acids and serves as a component of body tissues, enzymes, hormones,
etc., and is also an essential substance as a nutrient and as a source of energy. The nutritional value of
protein is mainly determined by the types and amount (composition) of constituent amino acids.
Therefore, the total intake of amino acids (protein intake) as well as the balance of amino acid
composition plays important roles when taking in proteins.
To that end, the Amino Acid Composition Tables summarizes the protein content and amino acid
composition of foods consumed by people on a daily basis as a basic material utilized for qualitative
evaluation of protein in foods.
Therefore, the current Composition Tables aims at a wide range of applications in various related
fields as a basic material which can be utilized for consideration of food policy, in the field of
research and education, etc., on top of the maintenance and promotion of public health.
2)
Properties
The Amino Acid Composition Tables lists the standard component values (composition) of amino
acids in important foods regularly consumed in Japan.
It is known that the component values of amino acids vary in accordance with various factors,
including the type, species, growing environment, processing method, etc. of plant/animal/fungus as
raw material. The component values listed in the current Composition Tables are values considered
representing the national average intake in a normal diet throughout the year in Japan, which were
determined based on the analysis values of samples obtainable from markets in Japan by normal
means, taking into account the variation factors for amino acid component values. In the Tables, one
set of standard component values is listed for one food product in principle.
3)
Background
The Amino Acid Composition Tables was first formulated and released as the Amino Acid
Composition of Food in Japan in 1966 by the Resources Council, Science and Technology Agency
(current Subdivision on Resources, Council for Science and Technology, Ministry of Education,
Culture, Sports, Science and Technology (MEXT)). In response to the diversification in diet,
improvement in the analytical technology, etc., the Amino Acid Composition Tables then underwent
drastic revision as part of a follow-up of the Standard Tables of Food Composition in Japan Fourth
Revised Edition, and in 1986, were released as the Revised Amino Acid Composition of Food
(hereinafter referred to as “Revised Amino Acid Composition Tables”).
In December 2010, the Subdivision on Resources, Council for Science and Technology, MEXT
summarized and released the Amino Acid Composition of Foods - 2010 - (hereinafter referred to as
“Amino Acid Composition Tables 2010”), along with the formulation of the Standard Tables of Food
Composition in Japan - 2010 - (hereinafter referred to as “Composition Tables 2010”).
Additionally, the Subdivision on Resources established the Expert Committee on Food Components
and has since endeavored to expand the information related to amino acid composition taking into
account factors including the change in diet in recent years. As a result, Standard Tables of Food
Composition in Japan - 2015 - (Seventh Revised Edition) - Amino Acids - (hereinafter referred to as
“Amino Acid Composition Tables 2015”) was summarized associated with the formulation of Standard
Tables of Food Composition in Japan - 2015 - (Seventh Revised Edition) (hereinafter referred to as “Food
Composition Tables 2015”) in December 2015.
1
Released Amino Acid Composition Tables are summarized in Table 1.
Table 1 History of the Amino Acid Composition Tables
Name
Amino Acid Composition of Food in Japan
Revised Amino Acid Composition of Food in Japan
Amino Acid Composition of Foods - 2010 Standard Tables of Food Composition in Japan - 2015 (Seventh Revised Edition) - Amino Acids -
4)
2
Released
Year
No. of foods
1966
1986
2010
157
295
337
2015
1558
Outline of review of the Amino Acid Composition Tables 2010
The changes from the Amino Acid Composition Tables 2010 to the Amino Acid Composition Tables
2015 include an increase in the number of foods by 1221, review of the item number, arrangement,
food name, etc. of food listed to be consistent with the Food Composition Tables 2015, and new
assignment of index numbers to foods. Additionally, from the viewpoint of ensuring convenience for
the users with the increased number of foods listed, the component values calculated from the ratio of
raw materials and those estimated from the composition tables available overseas were newly listed
for some foods. The components are the same as those in the Amino Acid Composition Tables 2010.
Standard Tables of Food Composition in Japan - 2015 - (Seventh Revised Edition) Amino Acids The weights of amino acids listed in the current Composition Tables are shown as per 100 g of edible
portion (Amino Acid Table 1) and per 1 g of reference nitrogen (Amino Acid Table 2), consistent
with the Food Composition Tables 2015.
Additionally, the weights per 1 g of protein, calculated as the sum of amino acid residues (Amino
Acid Table 3) and per 1 g of protein, calculated from reference nitrogen (Amino Acid Table 4, new
Table) are tabulated, resulting in a total of four Tables. The Tables are made available on the MEXT
website (see the notes below for the details of Tables available on the website). Reference nitrogen is
calculated by subtracting the following amount of nitrogen from the total nitrogen to approximate the
nitrogen in protein as possible: a) nitrogen in nitrate for Vegetables, b) nitrogen in nitrate and caffeine for
Teas, c) nitrogen in caffeine for Coffee, and d) nitrogen in caffeine and theobromine for Cocoa and
Chocolates. Therefore, the total nitrogen is the same amount as the reference nitrogen for foods that
do not contain nitrate, caffeine or theobromine. Data are presented as the amount of amino acids, not
as the amount of amino acid residues.
The Tables are prepared as follows: firstly the weight of each amino acid per 1 g of reference
nitrogen (Amino Acid Table 2) is determined based on analytical data, imputed data, or other data,
and then the weight of each amino acid per 100 g of edible portion (Amino Acid Table 1) is
calculated by multiplying by the weight of reference nitrogen. The “Protein, calculated as the sum of
amino acid residues” in Amino Acid Table 3 is calculated as the amount of dehydrated condensates
of each amino acid (the sum of each amino acid residue).
The “Protein, calculated from reference nitrogen” in Amino Acid Table 4 is calculated by
multiplying the nitrogen-protein conversion factors by the amount of reference nitrogen. The data of
each amino acid in Amino Acid Table 3 and Amino Acid Table 4 are also calculated using the data in
Amino Acid Table 2. The name of each Table is as follows.
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Amino Acid Table 1:
Amino acids per 100 g of edible portion
Amino Acid Table 2:
Amino acids per g of reference nitrogen
(note)
Amino Acid Table 3
:
Amino acids per g of protein, calculated as the sum of amino acid
residues (only released online)
Amino Acid Table 4:
Amino acids per g of protein, calculated from reference nitrogen
(only released online)
(Note): “Amino Acid Table 3” was described as “Amino acids per g of protein of edible portion” in
the Amino Acids Composition Tables 2010.
1)
Listed foods
(1) Classification and arrangement of food groups
The classification and arrangement of food groups are as shown below, according to the Food
Composition Tables 2015.
1 Cereals, 2 Potatoes and starches, 3 Sugars and sweeteners, 4 Pulses, 5 Nuts and seeds, 6 Vegetables,
7 Fruits, 8 Mushrooms, 9 Algae, 10 Fish, mollusks and crustaceans, 11 Meat, 12 Eggs, 13 Milk and
milk products, 14 Fats and oils, 15 Confectionaries, 16 Beverages, 17 Seasonings and spices, 18
Prepared foods
(2) Outlines
Foods have been selected under the following concepts used at the time of formulation of the
Revised Amino Acid Composition Tables and the Amino Acid Composition Tables 2010:
[1] Foods with high protein content and with large intake;
[2] Raw materials shall be those in a form closer to the form consumed; such as fish in fillet
not whole and,
[3] Regularly consumed processed foods with possibly altered amino acid composition.
On formulating the Amino Acid Composition Tables 2015, while ensuring the consistency with
the Food Composition Tables 2015 and utilizing the data in the Revised Amino Acid
Composition Tables and the Amino Acid Composition Tables 2010, reviews were made from
the viewpoint of ensuring convenience for users including the addition of newly analyzed foods
and estimates from similar foods or food composition tables available overseas. Specifically,
[1] For main foods widely consumed in Japan, selection is made from foods not listed in the
Amino Acid Composition Tables 2010 and foods newly listed in the Food Composition
Tables 2015;
[2] Foods not listed in the Food Composition Tables 2015 are not listed in the Amino Acid
Composition Tables 2015 in principle, excluding foods in Table 4;
[3] For foods with analysis values for “Raw”, the composition values of “Boiled”, “Baked”,
etc. per 100 g of edible portion are estimated based on it;
[4] Among unanalyzed foods, for foods unable to be estimated by [3] above and with similar
foods in food composition tables of foreign countries etc., the component values are
estimated using the data for the similar foods; and,
[5] Among unanalyzed foods, for processed foods with known raw material blending ratio and
amino acid component values, the component values are estimated using such values.
The estimated values derived by the method in [3], [4] or [5] do not reflect changes to the amino
acid composition by cooking nor differences between the foods available in Japan and overseas,
and therefore are listed in parenthesis. It is also described in the Remarks that the value is an
estimated value.
3
For the methods in [3] and [4], the estimated values are derived by applying the amount of each
amino acid per 1 g of reference nitrogen (per 1 g of nitrogen for overseas database) of the
referencing food to the amount of reference nitrogen of the subject food 1) 2). The referenced
food is shown in the Remarks for [3] and in Chapter 3 for [4]).
For the method in [5], the estimated values are derived by (a): multiplying the raw material
blending ratio by the amount of each amino acid per 100 g of edible portion of raw material that
constitutes at least 1% of total protein for the subject food and adding them up, (b): multiplying
the raw material blending ratio by the amount of protein per 100 g of edible portion of the
relevant raw material and adding them up, (c): dividing (a) by (b), and (d): multiplying the
amount of protein per 100 g of edible portion of the subject food by (c). The raw material
blending ratio used is those listed in Chapter 3 of the Food Composition Tables 2015.
As a result, the number of foods listed in the Amino Acid Composition Tables 2015 is 1558
(Table 1), as shown in Table 2 by food group.
Table 2 Number of foods listed in food group
Food group
No. of foods (Table 1)
1
Cereals
139
2
Potatoes and starches
32
3
Sugars and sweeteners
1
4
Pulses
81
5
Nuts and seeds
38
6
Vegetables
264
7
Fruits
102
8
Mushrooms
43
9
Algae
36
10
Fish, mollusks and crustaceans
320
11
Meat
233
12
Eggs
16
13
Milk and milk products
51
14
Fats and oils
5
15
Confectionaries
16
Beverages
8
17
Seasonings and spices
63
18
Prepared foods
4
122
Total
1558
(3)Notes on foods
See the Notes on Food Group in the Food Composition Tables 2015 for a detailed description
on each food.
[1] Foods shown in the column of Amino Acid Composition Tables 2015 in Table 3 are those
that cannot be clearly collated with foods listed in the Revised Amino Acid Composition
Tables. Therefore, amino acids per g of reference nitrogen (Amino Acid Table 2) for the
relevant foods are listed for foods listed in the column of Revised Amino Acid
Composition Tables. The component values of amino acids for Amino Acid Table 1,
Amino Acid Table 3 and Amino Acid Table 4 were calculated based on it, using the
amount of reference nitrogen, etc., obtained from the 5th Enlarged Composition Tables and
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the Composition Tables 2010.
Table 3
Correspondence table I for foods in the Amino Acid Composition Tables 2015 and
Revised Amino Acid Composition Tables
Amino Acid Composition Tables 2015
Item No.
10100
10237
10241
10292
10321
11003
11109
11150
11204
11240
Revised Amino Acid Composition Tables
Food name
Fish, righteye flounder, brown sole, raw
Fish, puffer, purple puffer, cultured, raw
Fish, yellowtail*, mature, raw
[*Syn. five-ray yellowtail]
Mollusks, Pacific oyster, cultured, raw
Crustacean, Kuruma prawn, cultured, raw
Rabbit, meat, lean, raw
Horse, meat, lean, raw
Pork, medium type breed, loin, without
subcutaneous fat, raw
Goat, meat, lean, raw
Guinea fowl, meat without skin, raw
Item No.
08-060
08-138
Food name
Righteye flounder, raw
Puffer, raw
08-141-a
Yellowtail, wild, mature, raw
08-179-a
08-219-a
09-004
09-034
Oyster, raw
Prawn, Kuruma prawn, raw
Rabbit, meat
Horse, meat
09-068
Pork, loin, without fatty meat
09-095
09-090
Goat, meat
Guinea fowl, meat
[2] Foods shown in the column of Amino Acid Composition Tables 2015 in Table 4 are those
not listed in the Food Composition Tables 2015, and only the item numbers that appear in
the Amino Acid Composition Tables are assigned. Amino acids per g of reference nitrogen
(Amino Acid Table 2) for the foods are the amino acid composition of foods listed in the
column of Revised Amino Acid Composition Tables (note that the component values
analyzed at the time of formulating the Amino Acid Composition Tables 2010 were listed
for “Mutton, loin, without subcutaneous fat, raw (11245)” and “Lamb, loin, without
subcutaneous fat, raw (11246)”).
The component values of amino acids in Table 1 are calculated by:
(a) deriving the amount of reference nitrogen using the amount of protein listed in Amino
Acid Table 1 of the Revised Amino Acid Composition Tables and the
nitrogen-protein conversion factors listed in Table 8 for foods other than those listed
in b) and c) below;
(b) deriving the amount of reference nitrogen using the pre-revision nitrogen-protein
conversion factor for “Sunflower seeds, dried (05038)” since its nitrogen-protein
conversion factor was revised in the 5th Enlarged Composition Tables; or,
(c) using the amount of reference nitrogen obtained by analyzing at the time of
formulating the Amino Acid Composition Tables 2010 are listed for “Mutton, loin,
without subcutaneous fat, raw (11245)” and “Lamb, loin, without subcutaneous fat,
raw (11246)”.
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Table 4
Item No.
01144
01145
05038
05039
09048
11245
11246
Correspondence table II for foods in the Amino Acid Composition Tables 2015 and
Revised Amino Acid Composition Tables
Amino Acid Composition Tables 2015
Nitrogen-protein
Food name
conversion
factor
Common wheat, instant Chinese
5.70
noodles, dried by frying
Common wheat, instant Chinese
5.70
noodles, dried by hot air
Sunflower seeds, dried
5.30 *
Hazel nuts, roasted
5.30
Algae, "Wakame", fruit-bearing
leaves, blanched and salted
6.25
products, salted
Mutton, loin, without
6.25
subcutaneous fat, raw
Lamb, loin, without
6.25
subcutaneous fat, raw
Revised Amino Acid Composition Tables
Item No.
01-031-a
01-031-c
06-019
06-021
Food name
Common wheat, instant Chinese
noodles, dried by frying
Common wheat, instant Chinese
noodles, dried by hot air
Sunflower seeds, dried
Hazel nuts, roasted
15-036-a
"Wakame", fruit-bearing leaves,
blanched and salted products, salted
09-092-a
Mutton, without fatty meat, loin
09-092-b
Lamb, without fatty meat, loin
* Changed from “5.40” in the 5th Enlarged Composition Tables.
(4) Name, classification, arrangement, item number and index number of foods
The name, classification, arrangement and item number of foods conform to those in the Food
Composition Tables 2015. Index numbers were newly assigned to each food. The index
numbers are common with those in the Food Composition Tables 2015 etc. Since the number of
foods listed varies depending on the composition table, there are index numbers that do not
appear in the current Composition Tables.
2)
Components
(1) Components and their arrangement
The arrangement of components is as shown below.
Amino Acid Table 1: Water, protein, protein calculated as the sum of amino acid residues each
amino acid, total amino acids, ammonia
Amino Acid Table 2: Each amino acid, total amino acids, ammonia, nitrogen-protein conversion
factor for protein calculated as the sum of amino acid residues
Amino Acid Table 3 and Amino Acid Table 4: Amino acid, total amino acids, ammonia
(2) Amino acids (Note)
[1] Data on the following 18 amino acids are included (19 amino acids for Fish, mollusks and
crustaceans, and Meat): isoleucine, leucine, lysine, sulfur-containing amino acids
(methionine, cystine), aromatic amino acids (phenylalanine, tyrosine), threonine,
tryptophan, valine, and histidine as essential amino acids that cannot be synthesized in the
body at all or sufficiently, and arginine, alanine, aspartic acid, glutamic acid, glycine,
proline, and serine as other amino acids. In addition, hydroxyproline is listed for Fish,
mollusks and crustaceans and Meat.
Asparagine and glutamine are hydrolyzed into aspartic acid and glutamic acid, respectively,
during protein hydrolysis, i.e., the pretreatment for amino acid analysis, and because it is
impossible to distinguish asparagine from aspartic acid or glutamine from glutamic acid
present in protein, asparagine and glutamine are included into aspartic acid and glutamic
acid, respectively. Cystine is a sum of cysteine and cystine (consisting of two cysteine
molecules), and is expressed as an amount of half-cystine. Amino acids constituting the
protein and free amino acids are not differentiated.
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The name, symbol and molecular weight (Mw) of amino acids are listed in Table 5.
(Note): See the explanation of amino acids (Page 15).
Table 5 Amino acids and their symbols and molecular weights
Amino acid
Mw
Symbol
Isoleucine
Ile
131.17
Leucine
Leu
131.17
Lysine
Lys
146.19
Methionine
Met
149.21
Cystine
Cys-Cys
240.30
120.15
Half-cystine
Phenylalanine
Tyrosine
Threonine
Phe
Tyr
Thr
165.19
Tryptophan
Trp
204.23
Valine
Val
117.15
Histidine
His
155.16
Arginine
Arg
174.20
Alanine
Ala
89.09
Aspartic acid
Asp
133.10
Glutamic acid
Glu
147.13
Glycine
Gly
75.07
Proline
Pro
115.13
Serine
Ser
105.09
Hydroxyproline
Hyp
131.13
sulfur-containing amino acids
SAA
–
aromatic amino acids
AAA
–
181.19
119.12
(Reference)
[2] The amino acids are arranged with essential amino acids first in alphabetical order, and
then non-essential amino acids in alphabetical order, in principle. Because part of
methionine and phenylalanine can be nutritionally replaced by cystine and tyrosine,
respectively, cystine is placed after methionine and tyrosine after phenylalanine.
Histidine is an essential amino acid because children cannot synthesize it in their bodies.
However, adults can synthesize histidine in their bodies, setting histidine apart from other
essential amino acids. For that reason, histidine is placed next to valine.
Arginine can be recognized as an essential amino acid or as a semi-essential amino acid
depending on the type of animal. For that reason, arginine is placed between essential
amino acids and non-essential amino acids to facilitate comparison with other non-essential
amino acids.
Additionally, a subtotal column is added for methionine and cystine as sulfur-containing
amino acids and for phenylalanine and tyrosine as aromatic amino acids, where the subtotal
amount was shown as “Amino acids, total”.
[3] The measurement methods for amino acids are outlined in Table 6.
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Table 6 Measurement methods for amino acids
Subject amino acids
General amino acids*
Hydroxyproline
Ammonia
Item
Measurement
method
Hydrolysis
condition
Measurement
method
Cystine
Methionine
Tryptophan
Hydrolysis
condition
Measurement
method
Hydrolysis
condition
Outline
Column chromatography (with amino acid automatic analyzer)
6 mol/L hydrochloric acid (containing 0.04%
2-mercaptoethanol)
110°C, 24 hours
[Measurement method for foods analyzed for the Revised
Amino Acid Composition Tables]
6 mol/L hydrochloric acid (containing 0.04%
2-mercaptoethanol)
100°C, 24 hours
Column chromatography (with amino acid automatic analyzer)
After oxidizing with performic acid,
6 mol/L hydrochloric acid
130-140°C, 20 hours
[Measurement method for foods analyzed for the Revised
Amino Acid Composition Tables]
After oxidizing with performic acid,
6 mol/L hydrochloric acid (containing 0.04%
2-mercaptoethanol)
150°C, 20 hours
High performance liquid chromatography
Barium hydroxide (containing thiodiethylene glycol)
110 °C, 12 hours
* Isoleucine, leucine, lysine, phenylalanine, tyrosine, threonine, valine, histidine, arginine, alanine,
aspartic acid, glutamic acid, glycine, proline, and serine
(3) Water and protein (protein, calculated from reference nitrogen)
From the viewpoint of ensuring convenience for users, regarding water and protein, the values
listed in the Food Composition Tables 2015 are included except for foods shown in Table 4. The
component values of foods shown in Table 4:
(a) conform to the 4th Composition Tables for foods other than those listed in b) or c) below.
(b) The component value of protein was calculated based on the nitrogen-protein conversion
factor revised in the 5th Enlarged Composition Tables for “Sunflower seeds, dried
(05038)”.
(c) The component values of water and protein conform to the re-analyzed component values
for “Mutton, loin, without subcutaneous fat, raw (11245)” and “Lamb, loin, without
subcutaneous fat, raw (11246)”.
The measurement methods in the Food Composition Tables 2015 pertaining to the foods
listed in the current Composition Tables are outlined in Table 7.
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Table 7 Measurement methods for water and protein
Component
Measurement method
Water
Air drying method, vacuum drying, or Karl-Fischer method
Protein
Calculated by multiplying the amount of nitrogen quantified by the improved Kjeldahl method or
the combustion method (improved Dumas method) by the “nitrogen – protein conversion factors”
(Table 8). For Coffee, caffeine is quantified separately and nitrogen originating from caffeine is
subtracted prior to calculating. For Cocoa and Chocolates, caffeine and theobromine are quantified
separately and nitrogen originating from them is subtracted prior to calculating.
For Vegetables, the total nitrogen including nitrate nitrogen is quantified using the salicylic acid
added improved Kjeldahl method, and nitrate nitrogen quantified separately is subtracted prior to
calculating. For Teas, the amount of nitrogen originating from caffeine and nitrate nitrogen are
subtracted prior to calculating.
Table 8 Nitrogen – protein conversion factors
Food group
1 Cereals
4 Pulses
5 Nuts and seeds
6 Vegetables
11 Meat
13 Milk and milk products
14 Fats and oils
17 Seasonings and spices
Food name
Amaranth
Common oats
oatmeal, raw3)
Barley3)
Common wheat
whole flour3)
wheat flour3), French bread, “Udon” (thick wheat noodles),
“Somen” (thin wheat noodles), yellow alkaline noodles,
macaroni and spaghetti3), “Fu” (wheat gluten cake),
wheat gluten,
outer steamed wheat “Jiaozi” (Chinese meat dumpling) dough,
outer steamed wheat “Shumai” (Chinese meat dumpling)
dough
wheat germ4)
Rice3), Rice products
(excluding “Sekihan” (steamed rice with adzuki beans or cowpeas))
Rye3)
Soybeans3), Soy products
Almonds3)
Brazil nuts3), Peanuts
Other nuts3)
Flax seeds, Pumpkin seeds, Poppy seeds, Sesame seeds3),
Watermelon seeds, Lotus seeds, Sunflower seeds
Soybeans, immature, Soybean sprouts
Peanuts (immature beans)
Gelatin5), Cartilage (Pork)
Liquid milk3), Dairy products including cheese, other
Butter3), Margarine3)
Soy sauce, Miso
Foods other than the above
9
Conversion
factor
5.30
5.83
5.83
5.83
5.70
5.80
5.95
5.83
5.71
5.18
5.46
5.30
5.30
5.71
5.46
5.55
6.38
6.38
5.71
6.25
(4) Protein, calculated as the sum of amino acid residues
Protein calculated as the sum of amino acid residues are the amount of dehydrated condensates
of amino acids based on the amino acid composition.
Protein, calculated as the sum of amino acid residues per 100 g of edible portion (g)
=∑ {amount of amino acid per 100 g of edible portion (g) × (molecular weight of the amino acid –
18.02)/molecular weight of the amino acid}
(5) Conversion factor for protein calculated as the sum of amino acid residues from reference
nitrogen
The conversion factor for protein calculated as the sum of amino acid residues is values derived
as the total amount of each amino acid residue from reference nitrogen per 1 g of reference
nitrogen.
When deriving the amount of protein for food, multiplying the conversion factor by the amount
of reference nitrogen of the food provides a more accurate amount of protein than the amount of
protein calculated by the conventional method where the conventional nitrogen-protein
conversion factor (Table 8) is multiplied by the amount of reference nitrogen.
(6) Ammonia
It is considered that a large majority of ammonia is generated during the hydrolysis process of
protein, mainly from amide groups in glutamine and asparagine, except those contained as
ammonia in food in small amounts. The amount of ammonia is listed in the Composition Tables
as information useful for estimating the amount of amino acids in an amide state.
Consideration was given to including the amount of ammonia into the amount of protein as
amide nitrogen from these amino acids. However, currently, there is not sufficient information
on the ratio of ammonia originating from amide groups and the calculated values of protein is
almost the same even if regarded in an amide state. Therefore, it was decided to provide the
amount of ammonia in a separate column as a reference.
Assuming all the amino acids quantifiable as glutamic acid or aspartic acid are in an amide state,
if subtracting ammonia for these amino acids leaves any remaining ammonia, the remaining
amount was shown in the Remarks as “Surplus ammonia”.
This “Surplus ammonia” is considered to be originating from non-protein nitrogen-containing
compounds. Especially for Vegetables, it was identified that part of nitrate nitrogen was
converted to ammonia during the process of quantifying amino acids, and it is considered that a
relatively large amount of “Surplus ammonia” originates from nitrate nitrogen.
(7) Remarks
In addition to the above-mentioned matters, names of raw materials of prepared food, blending
ratio of main raw materials, etc. were shown in the Remarks.
10
3)
Procedure of presenting values
The method of presenting values conforms to the rules below (see Table 9).
The unit of water, protein and protein by amino acid composition (protein, calculated as the sum of amino
acid residues) is g, and the values are shown to the first decimal place.
The unit of amino acids, total amino acids and ammonia is mg, and the values are shown as integers
(values less than 10 are shown to the first decimal place).
Values shown with decimal places are rounded off to the last decimal place presented. Values shown as
integers are rounded off at the third digit from the left to have two significant digits.
For each component, “0” indicates the value being less than 1/10 of the minimum listing value or not
detected, and “Tr (trace)” indicates the value contained is 1/10 or greater of the minimum value listed yet
less than 5/10.
Estimated values are shown in parentheses [see “2 1) (2) Outline of listed foods” for estimated
values].
Table 9 Procedure of presenting values
Item
Water
Protein
Protein, calculated as the
sum of amino acid residues
Amino acids
Amino acids, total
Ammonia
4)
Decimal places
in presentation
Unit
g
mg
Rounding method
1
Round off the second decimal place.
0
(1 for values less than
10)
Values shown as integers are rounded off at
the third digit to have two significant digits.
Values shown to the first decimal place are
rounded off at the second decimal place.
Cooking and preparation conditions
The cooking conditions used in the current Tables are essentially the same as those used in the Food
Composition Tables 2015. Basic cooking conditions are predetermined assuming general home cooking
(small-scale cooking). Cooking methods used in the current Tables are boiled, steamed, baked, sautéed, and
deep-fried, and the following foods are newly added in this revision: breaded and fried, and floured and
deep fried fish, mollusks and crustaceans, breaded and fried pork (“Tonkatsu”), floured and deep-fried meat,
tempura (fried with batter<= a mixture of flour, egg and water>) of sweet potato, eggplant and fish,
mollusks and crustaceans, microwaved sweet corn and glazed carrot. Boiling is done as preparation of
cooking, and the resultant broth is discarded. It includes post-boiling handling such as draining in a
colander or hand-squeezing after cooling.
Unheated preparation methods include bleached in water, soaked in water, and salted. Usually, preparation
of food accompanies the addition of condiments, yet condiments are not added in the current Composition
Tables, except for boiled macaroni and spaghetti, glazed carrot, and salted pickles, because it is difficult to
generalize the kind and amount of condiments to be used. See the Food Composition Tables 2015 for the
outline of cooking conditions for each food.
11
References
1)
Hitomi Suga, Kentaro Murakami, Satoshi Sasaki: Development of an amino acid composition database
and estimation of amino acid intake in Japanese adults. Asia Pacific Journal of Clinical Nutrition. Vol.
22, No. 2, p. 188-199 (2013)
2)
Yuki Kato, Rei Otsuka, Tomoko Imai, Fujiko Ando, Hiroshi Shimokata: Estimation of Dietary Amino
Acid Intake in Community-dwelling Middle-aged and Elderly Individuals Using a Newly Constructed
Amino Acid Food Composition Table. Japanese Journal of Nutrition and Dietetics, Vol. 71, No. 6, p.
299-310 (2013)
3)
FAO (the Food and Agricultural Organization of the United Nations)/WHO (the World Health
Organization): Energy and protein requirements, Report of a Joint FAO/WHO AdHoc Expert
Committee. WHO Technical Report Series. No. 522, FAO Nutrition Meetings Report Series, No.52
(1973)
4)
FAO: Amino acid content of foods and biological data on proteins. Nutritional Studies, No. 24 (1970)
5)
Merrill, A.L. and Watt, B.K.: Energy value of foods-basis and derivation-Agricultural Research
Service United States Department of Agriculture. Agriculture Handbook. No. 74 (1955)
12
[Reference]
Explanation
1
Amino acids
Amino acid is usually a general term for a compound that has an amino group (-NH2) and a carboxyl
group (-COOH) in one molecule. However, depending on the type of amino acid, a secondary amino
group [-N(H)-], which was called an imino group, may exist in place of the amino group (e.g. proline).
Amino acids are present in a free form as well as in a form of peptide by binding with other amino acids
in nature. However, a large majority of amino acids are present as a protein (polypeptide) that constitutes
the body of organisms.
Foods usually originate from organisms and their metabolic products, and so a large majority of amino
acids contained in foods are amino acids in proteins.
2
Peptide and protein
Because an amino acid has an amino group and a carboxyl group in one molecule, the amino group of an
amino acid and the carboxyl group of another amino acid can be bound by dehydration condensation and
form a covalent bond. This bond is called a peptide bond. Hydrolysis of peptide in the presence of acid
or alkali yields amino acids.
Compounds where multiple amino acids are bound through peptide bonds are called peptides. A peptide
consisting of 2, 3, 4 or 5 amino acids bound through peptide bonds is called a dipeptide, tripeptide,
tetrapeptide, or pentapeptide, and so forth depending on the number of amino acids bound. Peptides
consisting of 2-20 amino acids are collectively called oligopeptides(Note), and peptides consisting of more
than 20 amino acids are called polypeptides. Protein is polypeptide, and a large majority of amino acids
present in nature exist in the form of protein.
(Note) According to IUPAC&IUBMB1983, Oxford Dictionary of Biochemistry and Molecular
Biology Second Edition 2006, etc.
3
Amino acids present in nature
A large majority of free amino acids and amino acids that constitute peptides and polypeptides (protein)
present in nature are α-amino acids, which are amino acids where an amino group is bound to the carbon
atom to which a carboxyl group is bound [which is called 2- (or α-) carbon by the nomenclature of
organic compounds]. There also exist β-amino acids where an amino group is bound to 3- (or β-) carbon
atom, yet they do not constitute a large majority of proteins found in nature. α-Amino acids are simply
referred to as amino acids in the food data community.
4
Amino acids in proteins
Protein is a basic constituent of substances that maintain and adjust the physiological functions of tissues
in muscles, organs, blood, skeletal structure, skin, etc. as well as of enzymes, hormones, and immune
antibodies. Proteins normally consist of 20 types of amino acids, namely, in the order of the Japanese
syllabary, asparagine, aspartic acid, alanine, arginine, isoleucine, glycine, glutamine, glutamic acid,
cysteine (cysteine possesses a sulfhydryl group and a disulfide bond is formed between 2 cysteine
molecules through oxidation; the amino acid consisting of 2 cysteine molecules is called cystine; cystine
is more commonly observed than cysteine in natural proteins), serine, tyrosine, tryptophan, threonine,
valine, histidine, phenylalanine, proline, methionine, lysine, and leucine. A wide variety of proteins exist
in organisms, and a specific protein has a specific sequence of amino acids bound through peptide
bonds.
That is, the sequence of amino acids is always the same for a certain protein, which is transferred across
generations as genetic information coded in DNA (when there is a genetic difference in the sequence of
amino acids for a specific protein in the same species that is called genetic polymorphism).
13
5
Stereoisomers of natural amino acids
In amino acids, a hydrogen atom, an amino group and an atom group called a side chain are bound to the
carbon atom in the 2- (α-) position. Therefore, apart from glycine whose side chain is hydrogen, the
carbon atom in the 2-position becomes an asymmetric carbon atom, resulting in the amino acid having
stereoisomers and optical activity. According to the nomenclature recommended by IUPAC and IUBMB
(1983), stereoisomers of amino acids can be expressed as D and L, and amino acids that constitute proteins
are all L-amino acids except achiral glycine. Additionally, more commonly, the steric configuration of
substituents bound to the chiral center can be expressed by R and S. The steric configuration in regard to
the asymmetric 2-carbon as the chiral center is S for a large majority of amino acids that constitute
proteins, and R for cysteine.
Using alanine as an example, the structural formula of amino acid is shown in the Figure at the end, where
the covalent bonds related to the asymmetric 2-carbon are expressed in dash lines and wedges. This
drawing indicates that the carbon at the center is on the plane of the sheet, the carboxyl group and the
methyl group are behind the plane, and the amino group and hydrogen are in front of the plane.
Isoleucine and threonine have another asymmetric carbon atom at the 3- (β-) position, and have
stereoisomers for that asymmetric carbon as well.
6
Notation of amino acids
For amino acids, common names are widely used and their systematic names are rarely used. For their
symbols, 3-letter symbols are often used, yet 1-letter symbols are widely used especially in the field of
biochemistry to describe the amino acid sequence for proteins and peptides. See Table 10 at the end for
details.
7
Side chain of amino acids
Differences in the chemical properties of amino acids originate from differences in the side chain.
Occasionally, amino acids are categorized by the property of the side chain.
Branched-chain amino acids (the alkyl chain as the side chain is branched)
Isoleucine, leucine, valine
Acidic amino acids (there is a carboxyl group in the side chain, and their solution becomes acidic)
Aspartic acid, glutamic acid
Neutral amino acids (their solution is almost neutral)
Asparagine, alanine, isoleucine, glycine, glutamine, cysteine, serine, tyrosine, threonine,
phenylalanine, proline, valine, methionine, leucine, tryptophan
Basic amino acids (their solution becomes basic)
Arginine, histidine, lysine
Sulfur-containing amino acids (the side chain contains sulfur)
Cysteine, methionine
Aromatic amino acids (the side chain has an aromatic ring)
Tyrosine, tryptophan, phenylalanine
Hydroxyamino acids (the side chain has a hydroxyl group)
Threonine, serine, tyrosine, hydroxyproline
Acid amide amino acids (the side chain has acid amide)
Asparagine, glutamine
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8
Indispensable (Essential) amino acids
There are amino acids that an organism cannot synthesize in its body. Such amino acids are called
indispensable (essential) amino acids, and have to be taken in from food. For humans, 9 amino acids are
essential amino acids, namely, isoleucine, tryptophan, threonine, valine, histidine, phenylalanine,
methionine, lysine, and leucine.
Amino acids other than essential amino acids are called dispensable (non-essential) amino acids, and can
be synthesized in the body. There also are amino acids that can normally be synthesized in the body yet
the body fails to synthesize the amount required by the body due to physiological conditions, genetic
factors, etc. Such amino acids are sometimes called conditionally indispensable amino acids. Arginine,
cysteine (cystine), tyrosine, etc. fall under the category of conditionally indispensable amino acids.
9
Determination of amino acids
A large majority of amino acids in foods are present as amino acids in proteins (amino acid residues), and
only a small portion are present as free amino acids. Therefore, determination of amino acids in food requires
conversion of proteins and peptides into free amino acids through hydrolysis before measurement. The
stability and decomposability of protein or peptide against hydrolysis vary depending on the type of amino
acid. Because a large majority of amino acids are stable under acidic hydrolysis conditions, acid hydrolysis is
applied. However, because tryptophan is destroyed by acid hydrolysis, alkaline hydrolysis is used. Cysteine
can be partially destroyed by acid hydrolysis, and is converted to cysteic acid through oxidation prior to
hydrolysis. Methionine also is converted to methionine sulfone by oxidation before hydrolysis.
Acid amides, namely, glutamine and asparagine are converted to glutamic acid and aspartic acid, respectively,
during hydrolysis. Therefore, the amount of glutamic acid in the current Composition Tables is the total
amount of glutamic acid originating from glutamine and that of originally-present glutamic acid. Similarly,
the amount of aspartic acid is the total amount of aspartic acid originating from asparagine and that of
originally-present aspartic acid.
10 Evaluation of nutritional value of proteins
FAO/WHO and FAO/WHO/UNU (United Nations University) have released the standard composition of
indispensable amino acids that shall be contained in one’s diet (mg/g protein) as amino acid requirement
patterns. It is possible to evaluate the nutritional value of protein by comparing the amino acid requirement
patterns and the amount of amino acids in proteins in food. Among amino acids in proteins, those with their
amount below the amino acid requirement patterns are called limiting amino acids. Amino acid scores are
calculated by [weight (mg) of first-limiting amino acid per 1 g of protein] / [weight (mg) of the amino acid in
the requirement pattern] × 100.
When the Ministry of Health, Labour and Welfare formulated the Dietary Reference Intakes for Japanese
(2015), amino acid scores of protein taken in (average) are derived by calculating the intake of amino acids
from the protein intake by food group in the results of the National Health and Nutrition Examination Survey
and the amino acid composition of each protein. Because the so-derived amino acid scores were over 100
when referenced any of the 1973 FAO/WHO amino acid requirement pattern, 1985 FAO/WHO/UNU amino
acid requirement pattern, and the 2007 FAO/WHO/UNU amino acid requirement pattern, Japanese people
appeared to get good quality proteins from their diet.
11 Use of Amino Acid Composition Tables
By utilizing the data in the Amino Acid Composition Tables and the results of diet survey, amino acid intake
can be estimated. The intake of amino acids can be utilized for evaluating the diet and nutritional status of
individuals or groups. Especially, use of the current Composition Tables is vitally important for providing
meals with limited amount(s) of certain amino acid(s).
Although dietary reference intakes for indispensable amino acids have not yet been formulated for Japanese,
the current Composition Tables would serve as a basic material for formulating the dietary reference intakes
and for evaluating the dietary intakes.
15
Table 10 Common name, code and systematic name of amino acids that constitute proteins
(* indicates indispensable essential amino acids)
1)
Common name
Isoleucine
Leucine
2)
3-letter
code
Ile
Leu
1-letter
code
I
L
Systematic name
2-Amino-3-methylpentanoic acid
2-Amino-4-methylpentanoic acid
Lysine
Lys
K
2,6-Diaminohexanoic acid
Methionine
Met
M
2-Amino-4-(methylthio)butanoic acid
Cysteine
Cys
C
2-Amino-3-mercaptopropanoic acid
Phenylalanine
Phe
F
2-Amino-3-phenylpropanoic acid
Tyrosine
Tyr
Y
2-Amino-3-(4-hydroxyphenyl) propanoic acid
Threonine
Thr
T
2-Amino-3-hydroxybutanoic acid
Tryptophan
Trp
W
2-Amino-3-(lH-indol-3-yl)-propanoic acid
Valine
Val
V
2-Amino-3-methylbutanoic acid
Histidine
His
H
2-Amino-3-(1H-imidazol-4-yl)-propanoic acid
Arginine
Arg
R
2-Amino-5-guanidinopentanoic acid
Alanine
Aspartic acid
Ala
Asp
A
D
2-Aminopropanoic acid
2-Aminobutanedioic acid
Asparagine
Asn
N
2-Amino-3-carbamoylpropanoic acid
Glutamic acid
Glu
E
2-Aminopentanedioic acid
Glutamine
Gln
Q
2-Amino-4-carbamoylbutanoic acid
Glycine
Gly
G
Aminoethanoic acid
Proline
Pro
P
Pyrrolidine-2-carboxylic acid
Serine
Ser
S
2-Amino-3-hydroxypropanoic acid
Hydroxyproline
Hyp
-
4-Hydroxypyrrolidine-2-carboxylic acid
International Union of Pure and Applied Chemistry and International Union of Biochemistry and Molecular Biology IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN): Nomenclature and Symbolism for Amino Acids and
Peptides (Recommendations 1983) (http://www.chem.qmul.ac.uk/iupac/AminoAcid/, World Wide Web version prepared by
G. P. Moss.)
For hydroxyproline, there also exist isomers where a hydroxyl group is attached to the 3-carbon, yet the amount ratio of such
isomers is relatively small.
16
L - Alanine
D - Alanine
Figure. Stereoisomers of alanine
17