* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Amino Acids [PDF:247KB]
Survey
Document related concepts
Nitrogen cycle wikipedia , lookup
Ribosomally synthesized and post-translationally modified peptides wikipedia , lookup
Catalytic triad wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Citric acid cycle wikipedia , lookup
Butyric acid wikipedia , lookup
Fatty acid synthesis wikipedia , lookup
Metalloprotein wikipedia , lookup
Point mutation wikipedia , lookup
Proteolysis wikipedia , lookup
Peptide synthesis wikipedia , lookup
Genetic code wikipedia , lookup
Amino acid synthesis wikipedia , lookup
Transcript
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. 2 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 4 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)”. 5 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. 6 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. 7 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. 8 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 14 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