What is the nutrition of different flours? Is it safe to have additives in flour? How to choose flour?

   01

   What is wheat fragrance?

   When choosing wheat flour, many people like to choose the fragrant one, and think that the one with wheat fragrance is the best. The aroma components of wheat flour are mainly some hydrocarbons and alcohols. The factors that affect the smell of flour are as follows:

   1. Different varieties of wheat have different aromas.

   A study analyzed the aroma of 81 wheat varieties or local varieties in Denmark, and identified a total of 72 volatile components, and the aroma of different varieties of wheat flour will also be different.

   2. Production environment

   Even if the same variety of wheat is planted under different conditions such as water and soil, climate, and cultivation measures, the aroma will be different.

   3. Storage conditions

   Generally speaking, the newer the wheat, the stronger the aroma of the wheat. Fresh wheat is better both in terms of smell and nutrition. Due to storage conditions, such as temperature, humidity, gas composition, microorganisms and storage time, wheat flour will gradually lose its original fragrance and produce various odors, musty, sour and "ha" odors, and the color will become dark.

   4. The influence of refining process

   Since the wheat cortex contains more volatile components or volatile component precursors, the higher the degree of refining of wheat flour, the more the germ and bran are removed, the types of volatile substances in wheat flour are reduced, and the overall flavor is also weakening, that is, wheat Fragrance will deteriorate. Many people think that the current flour is not as fragrant as before, and a large part of the reason is because of refined processing. Most of the flour we eat now has been refined and processed, and the aroma of wheat will indeed be lost. However, many flours eaten at home a few decades ago were not so finely processed, and there are many whole wheat flours, and the aroma of wheat will indeed be more thicker.

   02

   What is the difference between different flours?

   Flour is made by grinding wheat grains, and the structure of wheat grains includes bran, endosperm, hypocotyl and germ, of which the cortex (including the outer skin and aleurone layer) accounts for 14.5%~18.5%, and the endosperm accounts for 77%~ 85%, embryos accounted for 1.1% to 3.9%.

   

   In the process of processing, different "flours" are formed according to the different parts of the wheat used, such as whole wheat flour, wheat core flour, snowflake flour, standard flour, etc.

   1. Whole Wheat Flour

   If the whole wheat is ground into flour, the bran (wheat skin), endosperm and germ (wheat bud) are all ground into flour, which is what we often call whole wheat flour. The characteristic of whole wheat flour is that it has not been refined, retains more bran and germ, and has higher nutritional value, because the minerals, vitamins and other nutrients of wheat are mainly concentrated in the bran. The disadvantage is that the taste is rough, and many people will find it unpalatable.

   2. Plain flour

   If the bran of the wheat is removed and the flour is mainly made of endosperm, it is ordinary flour, which is mainly distinguished from the whole wheat flour above. According to how much bran is removed (the degree of refining), it can be divided into ordinary flour, standard flour and refined flour. According to the different protein content, there are high gluten, low gluten and medium gluten. Normally, the protein content of high-gluten flour is above 12.2%, that of medium-gluten flour is around 11%, and that of low-gluten flour is generally less than 10%. The higher the protein content, the more chewy the dough, and the lower the protein (more starch) means the looser and softer the dough, and the less chewy the taste.

   3. Wheat Flour

   If higher processing precision is used to remove the outer part of the endosperm, and the more central part is used for grinding, the flour produced is wheat core flour. It is flour with higher processing precision than refined flour. It is characterized by white powder and good gluten quality. But because there is only endosperm, except for starch, there are very few vitamins and minerals left, so its nutritional value is the lowest. Because of its white color, some manufacturers also call it "snow powder".

   4. Germ powder

   If the endosperm is also removed and only the germ part is used to grind it into powder, germ powder is obtained.

   In fact, compared with whole wheat flour, ordinary flour, wheat core flour, and germ flour are all refined flour, but the degree of refinement is not the same.

   

   Many people may wonder why flour should be so refined?

   On the one hand, some flours do need to be processed. For example, high-gluten flour and low-gluten flour, high-gluten flour is suitable for making dumplings, medium-gluten flour is suitable for making steamed buns, low-gluten flour is suitable for making cakes, moon cakes, etc. This is the need for processing, and it is convenient for everyone to buy suitable flour for use.

   On the other hand, a lot of it is the result of marketing. For example, wheat core flour and germ flour are actually refined flour, but they are made by merchants for marketing differentiation.

   03

   How to choose flour?

   1. Healthy options, preferably whole wheat flour

   In terms of nutrition, whole wheat flour is the best. Whole wheat flour retains the bran and germ, and the dietary fiber, minerals, vitamins and other nutrients are better preserved. If you value health, it is recommended to choose whole wheat flour as much as possible . Moreover, the higher the degree of refinement, the greater the loss of nutrients. Like wheat core powder and germ powder, the nutritional value will actually be reduced.

   2. If you like the fragrance, you can choose whole wheat flour in terms of taste, usually whole wheat flour is more fragrant.

   Because most of the wheat-flavored substances are in the bran and germ, the whole wheat flour is not only particularly fragrant when kneading noodles, but also obviously more fragrant than ordinary flour after cooking.

   3. I like the soft and tender taste, choose refined flour in terms of taste, refined flour will be better than whole wheat flour.

   Because whole wheat flour has a lot of dietary fiber, it usually tastes rougher and harder, and the digestive burden will be greater. If you like a softer taste, you can choose flour with a whiter appearance and higher precision. Some people with poor gastrointestinal digestion can also choose refined flour.

   4. High cost performance, choose ordinary flour

   The reason why wheat core flour and germ flour are expensive is actually because rare things are more expensive. After all, the center of the endosperm and the germ are only a small part of the wheat grain.

   04

   Need to worry about food additives in flour?

   In order to improve the quality, various food additives are also used in the flour processing process. The common ones are gluten-enhancing agents, typically azodicarbonamide, and whitening agents, such as benzoyl peroxide.

   1. Benzoyl Peroxide

   Some people usually like pink and white flour when they buy flour. In order to meet the needs of consumers, flour manufacturers may use whitening agents, and the common one is benzoyl peroxide.

   Benzoyl peroxide (BPO is a commonly used food additive. In addition to whitening, it also accelerates the post-ripening of wheat flour (also known as ripening, ripening and aging), inhibits the mildew of wheat flour, and improves the yield of wheat flour. rate and other effects. Benzoyl peroxide was once a whitening agent and improver widely used in my country. However, my country banned the use of benzoyl peroxide in flour on May 1, 2011. Many people will think that it is because It is not safe. In fact, this is a complete misunderstanding. The reason why benzoyl peroxide is banned as a flour improver is mainly because public opinion thinks it is unnecessary, not because of safety issues.

   Before any additive is approved for use, it must undergo safety assessments by countries all over the world, and a "safety factor" is determined on the basis of the safety assessment, usually one hundred times, so as to obtain a "safe dose" for humans.

   The experimental data for this safety assessment is shared among countries. However, when it comes to specific management, each country will make choices according to its actual situation. For example, the United States believes that it is necessary to add flour whitening agent benzoyl peroxide to flour, so it is allowed to use; while China thinks it is not necessary, so its use is prohibited.

   In fact, at present, benzoyl peroxide is still a flour improver allowed to be used in many countries internationally. For example, the Codex Alimentarius Commission JECFA, the United States, Singapore and Japan all allow benzoyl peroxide to be used as a flour improver.

   2. Azodicarbonamide

   Azodicarbonamide is also a commonly used flour improver. It can make the flour more chewy and elastic when used in flour, thereby improving the taste of bread, and it also has a certain bleaching effect. Many people worry that azodicarbonamide is not safe. In fact, from authoritative food safety management agencies around the world, including the Joint Expert Committee on Food Additives (JECFA) of the Food and Agriculture Organization of the United Nations and the World Health Organization, the US Food and Drug Administration (FDA), the European Food Safety Authority (EFSA, 2005), etc. ; Judging from the evaluation results of azodicarbonamide, the safety of using azodicarbonamide in flour according to the standard is guaranteed, and it will not cause people to get cancer.

   Azodicarbonamide is used in flour, and its degradation products are not carcinogenic to humans. Some statements on the Internet compare it with veterinary drugs, and say that "the toxicity of the decomposition product of azodicarbonamide exceeds the standard by 90 times", which is completely misleading. One reason for others to consider it unsafe is the fear that businesses will overuse it.

   First of all, my country has strict restrictions on the use of azodicarbonamide in flour. According to the national standard "Standards for the Use of Food Additives" (GB2760-2014), the scope of use of azodicarbonamide is wheat flour, and the maximum usage is 0.045g/kg. If the amount of azodicarbonamide added to wheat flour does not exceed 0.045g/kg, it is in line with the national standard and is beyond reproach, and it is also a normal production, and there is no problem of violation of laws and regulations. It is illegal to use in excess.

   Secondly, azodicarbonamide is not like some people say, producers can add it at will. If you add less, the gluten-enhancing effect will be insufficient, and the dough will easily burst and crack during baking. If you add too much, it will be too chewy, and the air bubbles will not be able to open during baking, and the bread will be small and hard. Therefore, in actual production, there are strict technical requirements for adding azodicarbonamide, and companies will not add it casually. .

   Although the possibility of abuse by some small businesses and small workshops cannot be ruled out, it cannot be banned because of this, right? Do people need to be prohibited from driving if they run red lights or drink and drive? As for some countries, azodicarbonamide is not used because of poor risk management. The same, or there are better alternatives, and banning a certain country does not necessarily mean that it is unsafe, which is also common in the food industry.

   

   Talc powder is indeed a food additive, but it is not allowed to be used in flour, and it is illegal to use it. However, borax and borax are not food additives at all, but illegal additives, which are strictly prohibited from being used in food.