Bread is a food made by grinding and heating a grain (generally wheat). Wheat flour as the main raw material, yeast, eggs, oil, nuts, etc. as auxiliary materials, add water to prepare the dough, after fermentation, molding, molding, baking, cooling and other processes processed from the baked food.
Bread can also be categorized into two types, namely, staple food bread and dessert bread. It can be divided into four categories: "soft bread," "crispy bread," "candied bread," and "hard bread." According to raw materials can be divided into white bread, whole wheat bread and multi-grain bread.
[calories]: The calories generated by food are calories. The calories used in nutrition are kcal, and the calories are the calories needed to make one kilogram of water rise by one degree Celsius. 1 gram of protein in the body absorbs and oxidizes to produce 4 kcal of calories, 1 gram of sugar in the body absorbs and oxidizes to produce 4.1 calories, and 1 gram of fat absorbs and oxidizes in the body to produce 9.3 kcal of calories. From the above figures, the calorie content of food can be calculated from its composition. For example, for every two loaves, there are 11.1 grams of carbohydrates, 0.6 grams of fat, and 3.1 grams of protein, then 1 pound of bread. The heat generated is as follows:
ã€Carbohydrates】: 16×11. 2×=716. 8 kcal
[fat]: 16×0. 6×9=86. 4 kcal
Protein: 16×3. 1×4=198. 4 kcal
[total]: 1001. 6 kcal
Each person has the minimum amount of calories he needs to maintain his life. Usually men need 1,700 kcal per day. Women need 1400 kcals a day. In addition, due to different occupations, each person consumes different energy. Therefore, they need another calorie. The additional calories are between 1000 and 3,000 kcal. As for the calories required by children, Its age is divided, but also depends on the size of the body and the number of activities to decide. The following table shows the average number of calories needed per day:
1650 kcal for children before age 6
6 to 10 years old 2300 kcal
10 to 14 years old 2700 kcal
Women 2300~2750 kcal
Male 2750~5000 kcal
For people who consume more energy, such as miners, blacksmiths, and sawmillers, the calorie requirement is also higher than the average person. Each person may need more than 5,000 kcal per day.
Dietary value
Bread is the most complete nutrient content in human food. The reason is that the nutrient that is usually lacking in bread is fat, but when it comes to bread, it is often added with butter or Macchia. Because its main ingredient is carbohydrates, people like to eat together with foods high in fat or protein. The nutritional value of wholegrain bread is different from that of white bread. The differences are as follows:
White bag and whole wheat bread ingredients comparison
Water Protein Fat Starch Cellulose Minerals
White bread 40. 0 6. 5 1. 0 51. 2 0. 3 1. 0
Whole wheat bread 45. 0 6. 3 1. 2 44. 8 1. 5 1. 2
From the above table, it can be seen that the white bread contains higher protein than whole wheat bread, and the fat content is lower.
Digestibility
After cooking or baking flour protein is easier to digest, because the gluten it produces is easily in contact with the digestive juice, so bread is easier to digest than other foods. Wheat protein is the best among all cereals, but it is still a second-class protein because it cannot be fully utilized in the body. Therefore, we should add animal protein together when we eat. However, the nutritional value of bread added with milk powder during production is even higher.
Fat is usually easily absorbed. The digestibility of fat is affected by its melting point. The melting point of fat in wheat is 50°F. It is usually liquid, so it is easily digestible. Because the fat in wheat is concentrated in the germ, germ bread More digestible than regular bread.
Digestion of bread starts from the oral cavity. The digestion of saliva changes the starch to dextrin and maltose. The amount of conversion depends on the complete degree of chewing of the bread. Therefore, the fresh bread has little contact with saliva because of its high moisture content. The degree of digestion in the oral cavity is also less, but the degree of digestion of the baked toast bread or biscuit in the mouth is relatively complete, because when the chewing, the dry food promotes the secretion of saliva to completely blend the saliva.
The bread stays in the stomach for about 3.5 hours until its protein properties change. Fresh bread forms a thicker piece in the stomach and is less likely to be saturated with digestive juices. In the small intestine, the digestion of starch and protein in the bread is complete, and absorption takes place here.
Comparison of digestibility of various types of food and bread
Types of food Energy available for protein, fat, carbohydrates (%)
Milk Products Milk Cream Cheese 97 95 98 93
Grains (including bread), vegetables, eggs, fruits, meat, and fish, dried beans compared with meat, protein loss (about one-fifth), the more obvious cereals. However, the absorption rate of mineral salts is certain, so although the mineral content of whole wheat bread is high, it cannot be completely absorbed. Absorption of protein varies according to the amount of carbohydrates contained in the food. With this diet (if whole wheat bread), the protein absorption rate is as high as 95%.
When whole wheat bread is digested, the absorption rate of nutrients is not as good as that of white bread because of its high fiber content. The similar fiber material will prevent digestive juice and nutrients tightly together.
Maipi is important for stimulating the small intestine, especially for some people. The incomplete absorption of nutrients in whole wheat flour is due to the incomplete milling. If the wheat skin is also as fine as the flour, its absorption rate will increase, and its mineral salts will be more easily absorbed. So at present, everyone loves to use refined flour.
Another important nutrient of bread is vitamins and mineral salts. Its content in all parts of wheat is different. Wheat has the lowest protein content in the endosperm, but the closer it is to the wheat husk, the higher its protein content is. Therefore, the proportion of protein contained in high-gluten flour is higher. In the protein-containing part of wheat, it also contains a large amount of iron, vitamins and niacin. The protein contained in the germ. There are many iron and vitamins. The amount of vitamin B contained in the cotyledons also exceeds that contained in the bran. This principle was discovered during the Second World War. The cotyledons of wheat can be separated and added to the various flours in various countries. This is a great achievement of the Valley Research Association in World War II. Cotyledons only weigh 1.5% in wheat, but they contain about 59% of vitamin B.
Phytic acid has a great influence on the flour making process. Because this acid contained in bran will form insoluble calcium salts in the body during digestion. Calcium combined with phytic acid in the body comes from food, such as milk and eggs. Therefore, incorporation of insoluble calcium salts can lead to the formation of rickets due to the lack of calcium. During the Second World War, this phenomenon had occurred in Ireland, because it used whole wheat flour and lacked other supplementary foods. The effect of absorption of calcium phytate in the United States is gradually understood due to long-term research. When eighty-five percent of refined flour is used, seventy-two grams of calcium are added per bag (in lieu of lime). Ninety percent of refined flour was later used when adding calcium in fourteen bags. This standard has been in use since 1946.
When 85% of flour is refined, the content of phytic acid (Phytic acid) is three times higher than that of 72% flour, and that of whole wheat flour is up to six times. The iron content of cereals is up to the skin.
Iron content of flour
The degree of refinement (flour) The content of iron (mg/100)
100% 3. 1
85% 2. 2
80% 1. 7
70% 1. 4
It can be seen that the amount of iron in flour without added additives varies depending on the degree of refinement.
The following table points out that the whole wheat flour contains more iron than white flour. However, the amount of iron absorbed in the body varies depending on the needs of the human body and the iron content of food. Not all iron contained in whole wheat bread is absorbed because it is difficult to absorb such a complex organic molecular structure. Whole-wheat bread contains a protein that is not found in white bread. This protein makes iron insoluble, which impedes the absorption of iron in the small intestine. Whole wheat bread contains phytic acid, and the formed phytic acid is completely insoluble. In addition, phosphoric acid and iron also form insoluble iron phosphate. Therefore, a small amount of iron should be added to various flours.
vitamin
A. Vitamin A--In the ordinary white bread, there is almost no existence of vitamin A. If bread is made from unbleached flour, there may be a small amount of carotene present in the dough. But when baked, they are destroyed by oxidation. The amount of vitamin A in the germ bread is also very slight. Although it contains a relatively large amount of carotenoids, the germ is more susceptible to heat and it is substantially lost after baking. In particular, butter was added to the production process and no vitamin A was included after baking.
B. Vitamin B - The most important B1 (antineuroinflammatory), B2, and niacin in bread. In addition to the above three, there are four or more complex vitamin Bs present in food, such as vitamin B6 pantothenic acid, biotin, and folic acid, but all are missing in bread.
In 85% of the refined flour, although some vitamin B is still contained, approximately one-fifth is lost during baking. Although modern studies have not learned up to one-fifth. However, if baking soda is used as an expanding agent, all vitamin B is destroyed.
Vitamin B1 is sometimes lacking because of abnormalities in the digestive tract, such as gastric or intestinal ulcers.
Whole wheat bread and germ bread are highly recommended because they contain more vitamin B1.
If bread is used with enough yeast, it can supplement the deficiency of vitamin B1. However, adding 30 to 60 grams per 280 pounds of flour is not very useful, but only increases the B1 content.
Wheat germ contains more B1 and B2, but yeast has more B2 than B1. Vitamin B2 is more stable than B1, although both are stable to heat.
Some things about wholemeal bread:
(a) Whole-grain bread containing no germ contains less vitamin B2 than germ-containing whole-grain bread, but more than white bread.
(b) The nutritional value of germ bread is not as high as most people think. The content of vitamin B1 is only slightly more than normal whole wheat bread, but it is several times larger than white bread.
a. Vitamin B2-- contains riboflavin in all germ breads, but contains less in white bread.
b. Niacin acid - is contained in wheat, yeast and germ.
c. Vitamin B6 - less in wheat and more in yeast.
If the content of yeast in the bread reaches the actual percentage of 0.4%, the content of vitamin B2 is enough to supply the body's needs.
When making bread with a chemical bulking agent, it is easy to destroy vitamin B1. At present, many of these breads are eaten by people with stomach problems. Therefore, the lack of B1 is worth noting.
C. Vitamin C - Vitamin C is not included in cereals.
Existing people are trying to promote a kind of tomato bread, but vitamin C is extremely unstable, so whether the final product contains vitamin C is a problem.
But vitamin C can enhance the taste of bread. For example, eating bread or biscuits together with orange juice or orange juice tastes excellent.
If there is a secondary baking method, vitamin C does not exist at all, because of the oxidation in the dough, not the nature of vitamins.
D. Vitamin D - exists in two forms, D2 and D3, initially dissolved in a vegetable oil that can be used for bread. After baking, vitamin D still remains. If two pounds of dough originally contained 280 units of vitamin D, they still contain 24