FOOD COMPOSITION TABLE FOR USE IN EAST ASIA
PART I
PROXIMATE COMPOSITION, MINERAL AND VITAMIN CONTENTS OF EAST ASIAN FOODS

EXPLANATION ON FOOD COMPOSITION TABLE
PART I

Sources of Data. In compiling the data collected on Asian foods, emphasis was put on critical evaluation of local data already available within the region, and determining the nutrient-gaps remaining to be filled. Whenever possible, the appropriate local data were applied in deriving a representative value for each individual food commonly used in the East Asian region. In other cases, arrangements were made for analysis of 59 Asian foods by the Wisconsin Alumni Research Foundation, Inc., in the USA, and of 155 Asian foods by the Food Industry Research and Development Institute, in Taiwan, to fill gaps in nutrient information. Special funds were provided by NIH for this work done by these two organizations.

When food samples were not available on time for analysis, or original data were negligible, calculated or imputed values of the same food from other regions, with the identical scientific names, were applied when such substitution proved useful and reasonable. Such data are indicated by parentheses throughout this food composition table. For certain imported foods, values from countries of origin are applied, and no parentheses are used. For food indigenous to certain areas, when only local analyses are available, such analyses, if reasonable, as well as local names, have been applied. Some local foods for which analytical data were not found are not listed in the food table.

Cases in which a single analysis was available, and values were in doubt, are indicated by a question mark. A nutrient column left blank signifies no available analytical data, or the omission of questionable data.

Because many Asian foods or food products are preserved by sun-drying whenever feasible, such uncooked products are presented as nearly as possible in rehydrated form. It is hoped that in the near future, as studies are made to determine the loss of nutrients during cooking, these products can be calculated into cooked products.

Useful references concerning food composition data, from which representative values of Asian foods presented here were derived, are listed as Appendix 6.

Nomenclature Used. Because of differing local names, scientific names are used as the basis for data entry, in compilation of the analytical data of Asian foods.

Most of the English names used in this food table are those suggested in the “Standardized Plant Names”, prepared for the American Joint Committee on Horticulture, and the “Dictionary of Economic Plants”, by J.C. Th. Uphof. Other references cited in Appendix 7, concerning the botanical nomenclature of Asian foods, also prove useful.

Food Groups. The foods selected for inclusion in the table are grouped into 14 major groups, as listed below, according to local eating habits. Such groupings have also been used in the African regional food composition table. The quantitative data of each food grouping of different segments or population in each world-region, therefore, can be assessed. Comparison can also be made between regions, with regard to their consumption habits, patterns, and levels of different groups, as well as their food trends.

In classifying foods belonging to Group 2 (Starchy Roots, Tubers and Fruits), two criteria were applied. First, those starchy foods, whose total carbohydrate “by difference” content, in terms of the raw product, is 20% or over, and which are consumed in substantial amounts, are included in this group. Second, those starchy foods of which the amount consumed is very limited, and which are used as fruits or vegetables, are classified as fruits or vegetables, respectively. For the convenience of the users, cross-indexes are applied.

Food Groups

Food Energy. The specific physiological energy factors used in other regional food composition tables (Appendix 1) have been adopted for use in calculating the food energy in this table. In view of the great variety of dietary patterns in Asia and because of inadequate existing studies on the digestability of Asian foods by Asian subjects, the Atwater system of calculating energy values, expanded as shown in the U.S. Department of Agriculture Handbook No. 74, “Energy Value of Foods--Basis and Derivation”, has been used.

Protein. Protein values are computed from the nitrogen content, as determined by the Kjeldahl method, multiplied by a conversion factor. Since most of the proteins contain approximately 16 percent nitrogen, a 6.25 factor is generally used for conversion of nitrogen to protein. For certain other foods in which the percentage of nitrogen in protein differs, the following specific factors for converting nitrogen to protein, as originally suggested by Dr. Breese Jones,¹ were used here as well as in the previous regional food tables for Africa and Latin America.

¹ Jones, D.B.: Factors for converting percentages of nitrogen in foods and feeds into percentage of protein. U.S. Dept. Agric. Cir. 183, 22 pp. (Slightly revis. edit.), 1941.

Because the consumption of mushrooms, fungi, and seaweeds is very common in Asian countries, special analyses on these food items were made by the Wisconsin Alumni Research Foundation, Inc., with regard to the percentage of non-protein nitrogen present. It was found that approximately 29%, or one-third of the nitrogen in the mushrooms and fungi, and about 20%, or one-fifth of the nitrogen in seaweeds, are counted as non-protein nitrogen.

In calculating the protein value for these products in the protein column, the nonprotein nitrogen in excluded. In order to avoid overestimating their carbohydrate content, crude protein (including nitrogenous matter and nonprotein nitrogen) was used for calculating the carbohydrate by difference of these products in the food table.

Carbohydrate. Carbohydrate in the food table presents the total carbohydrate by difference including fiber--that is, the sum of moisture, protein, fat, and ash is subtracted from 100. Nitrogen-free-extract can be calculated by subtracting crude fiber from carbohydrate.

Minerals. Calcium, phosphorus, and iron values given in this table represent the total content of each nutrient, without deduction for the unutilized portion.

Although leafy green vegetables, which are consumed in large quantities by Asians, contain considerable amounts of calcium, all of the calcium appearing in these products may not be fully utilized, due to the presence of oxalic acid or of phytates. Studies, therefore, are needed of the oxalic acid and phytate content, and the available iron in various commonly used Asian foods.

Due to limited analyses being done in cooked foods, it is noted, quite often, that analyses reported on cooked products show higher in calcium and sometimes in iron than in the corresponding raw products. The reasons, such as the cooking water, cooking utensils, or other factors, remain unknown, and need further investigation. It is advisable for laboratories undertaking food analyses to provide detailed information on the foods and their condition at the time of cooking.

Sodium and Potassium. Analyses done for sodium and potassium in East Asian foods are used directly in this food table. Whenever such data were not available, calculated or imputed values from other regional sources have been applied.

Vitamin A. In accordance with the recommendations made by the joint FAO/WHO Expert Group on “Requirements of Vitamin A, Thiamine, Riboflavin, and Niacin,” (FAO, Report Series No. 41, 1967) the vitamin A values in this food table are expressed in terms of “retinol”, which refers to vitamin A alcohol, and the “beta-carotene equivalent”.

The conversion factors used for calculating these from International Units or from micrograms of vitamin A activity, listed below, are the same as applied in the previous regional food table for use in Africa.

When analytical data for vitamin A are reported in International Units (I.U.), the following factors were used for conversion to micrograms of retinol, beta-carctene, and other carotenoids.

If the values were expressed in micrograms of vitamin A activity, the following factors were used for conversion of micrograms of retinol, beta-carotene, and other carotenoids to a common denominator of micrograms of retinol.

One mcg. vitamin A value = 1 mcg. retinol
One mcg. beta-carotene = 0.5 mcg. retinol
One mcg. other total mixed carotenoids = 0.25 mcg retinol

The estimated distributions of sources of vitamin A activity in various foods (as suggested for use in the Latin American food composition table, and adopted by the FAO/WHO Expert Group in the meeting concerning requirements of vitamin A) are listed as follows:

Estimated Distribution of Sources of Vitamin A Activity in Various Foods

These estimates have been applied in calculating retinol and beta-carotene equivalents in this food table.

Ascorbic Acid. Ascorbic acid values are expressed in terms of total ascorbic acid, instead of reduced ascorbic acid.

Refuse. The percentage of refuse (inedible portion) in 100 grams of food gross, or as purchased weight, is included in the first column of the food table.

Inedible portion was determined in 70 Asian foods by the Food Industry Research and Development Institute in Taiwan, and in about 385 foods were voluntarily studied by the local nutritionists in Burma, Thailand, Singapore, and Indonesia. These data were used in calculation of the food values in terms of gross or as purchased weight.

The portion considered inedible varies from place to place, and consumer to consumer. In this table, the nature of the inedible portion is specifically described to aid the reader and permit him to arrive at his interpretation of total food value.

Conversion Factors of Weight Units Used in East Asia. For the convenience of users in various Asian areas, the factors for converting weights commonly used in Asia to metric and avoirdupois equivalents, were compiled and attached as Appendix 2.

SUMMARY AND RECOMMENDATIONS

This East Asian food composition table is the first of a series of regional food tables in which an attempt has been made to fill in nutrient-gaps as much as possible during three years of research. It is also the first regional table which, in one single publication, includes data on amino acids, fatty acids, trace elements, certain B-vitamins, sodium and potassium. It also provides information on the inedible portion of numerous indigenous foods, increasing its usefulness in evaluating the food consumption of Asian people in this region.

Of a total 1629 items selected for inclusion, 1037 are derived from edible plants. Fruits, vegetables, and starchy roots, tubers represent 726 items; cereals and grain products 110 items; grain legumes and legume products 111 items; nuts and seeds 71 items; and sugars and syrups 18 items.

Various food consumption studies in Asia indicate that cereals and grain products contribute the bulk of food energy. More studies of the amino acid composition and of the biological values of the proteins of these cereals and grain products are therefore needed.

The study of the phytin content in such grain products is also important because an immeasurable binding of calcium and other minerals to phytin interferes with their full utilization.

Considerable amounts of calcium and iron are contributed by leafy green vegetables. Study of the factors affecting the high calcium and iron content reported in foods is essential, whether or not that high content is due to contamination during sampling, or conditions under which foods were produced, or the nature of the food itself. Moreover, the oxalic acid content of fruits and vegetables should be determined, because it interferes with effective utilization of calcium.

Continuing efforts should be made to evaluate local methods of food preparation, cooking, processing, and milling in relation to their effect on nutrients.

Information on the coefficient of digestibility of East Asian foods in human subjects living in Asia is urgently needed, for use in deriving specific energy factors in calculating the calorie value of protein, fat, and carbohydrate in various foods.

It is strongly recommended that local laboratories undertaking food analysis programs be encouraged to utilize the latest standardized analytical procedures, and to maintain their effort to provide now missing data on nutrients of locally grown or processed foods, since the food composition table is the basic tool for evaluating dietary intake in relation to the nutritional status of population groups.

For future use, local food scientists are urged to identify indigenous foods in terms of the accepted scientific names as well as common names. They should describe fully the analytical methods applied, and the variety, maturity, time of harvest, length of exposure in the market, part of sample analyzed, and the part considered inedible, for these directly affect the nutrient values reported.

In compilation of this Asian food table, it was noted that many indigenous foods, sometimes not wisely used, are not only rich in certain essential nutrients, but also practical and economical for menu planning consistent with local eating habits. Such foods should be advocated for greater daily use, and some would be valuable in formulating infant foods and/or protein-supplements, as well as for determining agricultural production goals.

TERMS AND SYMBOLS

Note: Special thanks are expressed to Mrs. Barbara B. Crumpler for her valuable assistance in typing the whole manuscript and the entire food composition table.