Why is flour not as fragrant as before? Is it safe to add additives? The truth is...

Flour is a food we often eat. Dumplings, steamed buns, flower rolls, steamed stuffed buns, cakes, etc. are all inseparable from it.

However, recently it has also been shackled by "technology and hard work". There are some videos about flour "technology and hard work" on the Internet. The video bloggers say that different types of flour and additives in flour are harmful to health, which makes many people feel uneasy: they can't even eat noodles with peace of mind!

What are the nutritional values ​​of different flours? Are additives in flour safe? How to choose flour?

01

What is wheat fragrance?

When choosing wheat flour, many people prefer to choose the one with a good smell, thinking that the one with wheat aroma is good. 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 Danish wheat varieties or local varieties, and identified a total of 72 volatile components. The aroma of wheat flour from different varieties will also be different.

2. Origin environment

Even the same variety of wheat will have a different aroma if grown under different water, soil, climate, cultivation measures and other conditions.

3. Storage conditions

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

4. Impact of refining process

Since the wheat cortex contains more volatile components or volatile component precursors, the higher the degree of wheat flour refining, the more germ and bran are removed, the fewer types of volatile substances in the wheat flour, and the overall flavor continues to weaken, that is, the wheat flavor will deteriorate. Many people feel that the flour nowadays is not as fragrant as before, and a large part of the reason is because of the refining process. Most of the flour we eat now has been refined, and the wheat flavor will indeed be lost. However, many of the flours we ate at home decades ago were not so finely processed, and there was a lot of whole wheat flour, so the wheat flavor was indeed stronger.

02

What are the differences between different flours?

Flour is made from crushed wheat grains, and the structure of wheat grains includes bran, endosperm, hypocotyl and germ, of which the cortex (including the outer skin and endosperm) accounts for 14.5%~18.5%, the endosperm accounts for 77%~85%, and the embryo accounts for 1.1%~3.9%.

During the processing process, 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, that is, the bran (the skin of the wheat), endosperm and germ (the sprout of the wheat) are all ground into flour, which is what we often call whole wheat flour. The characteristics of whole wheat flour are that it has not been refined, and more bran and germ are retained, and the nutritional value is higher, because the minerals, vitamins and other nutrients of wheat are mainly concentrated in the bran. The disadvantage is that it tastes rough, and many people think it is not delicious.

2. Plain flour

If the bran of wheat is removed and the flour is mainly made of endosperm, it is ordinary flour, which is mainly distinguished from the whole wheat flour mentioned 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 protein content, there are high-gluten, low-gluten and medium-gluten. Usually, the protein content of high-gluten flour is above 12.2%, medium-gluten flour is around 11%, and the protein content of low-gluten flour is generally less than 10%. The higher the protein content, the more chewy the dough is. The lower the protein content (the more starch), the looser and softer the dough is, and the less chewy it tastes.

3. Wheat core flour

If the outer layer of the endosperm is removed with higher processing precision and the central area is used for grinding, the flour produced is wheat core flour. It is a flour with higher processing precision than refined flour, and its characteristics are white powder and good gluten quality. However, since only the endosperm is left, except for starch, there are very few vitamins and minerals left, so its nutritional value is the lowest. Due to its white color, some manufacturers also call it "snowflake flour".

4. Germ powder

If the endosperm is removed and only the germ part is ground into powder, germ flour is obtained.

In fact, compared to whole wheat flour, ordinary flour, wheat core flour, and germ flour are all refined flours, but the degree of refinement is different.

Many people may wonder why flour needs to be so refined and differentiated?

On the one hand, some flours are indeed needed for processing. 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, and low-gluten flour is suitable for making cakes and moon cakes. This is a need for processing, so that everyone can buy the right flour when using it.

On the other hand, many of them are the result of marketing. For example, wheat core flour and germ flour are actually refined flours, but they are made by merchants for marketing differentiation.

03

How to choose flour?

1. Healthy choice, whole wheat flour is the first choice

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 more nutritional loss. For example, wheat core flour and germ flour actually have lower nutritional value.

2. If you like aroma, you can choose whole wheat flour. In terms of taste, whole wheat flour is usually more fragrant.

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

3. If you like a soft and tender texture, choose refined flour. In terms of taste, refined flour is better than whole wheat flour.

Whole wheat flour usually has a rougher and harder texture due to its high dietary fiber content, and is more difficult to digest. If you prefer a softer texture, you can choose flour that is whiter in appearance and has a higher precision. Some people with poor gastrointestinal digestion can also choose refined flour.

4. Cost-effective, choose ordinary flour

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

04

Should I worry about food additives in flour?

In order to improve the quality, various food additives are also used in the flour processing process. Common ones include gluten enhancers, the typical representative of which is azodicarbonamide, and whitening agents, such as benzoyl peroxide.

The video says that these additives are harmful to health. Is this true?

1. Benzoyl peroxide

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

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

Any additive must undergo safety assessments by countries around the world before being approved for use, and a "safety factor" must be determined based on the safety assessment, usually one hundred times, to obtain a "safe dose" for humans.

The experimental data of this safety assessment is shared by all countries. However, when it comes to specific management, each country will make choices based on its own actual situation. For example, the United States believes that it is necessary to add benzoyl peroxide, a flour whitening agent, to flour, so it allows its use; while China believes that it is unnecessary, so it prohibits its use.

In fact, benzoyl peroxide is still allowed to be used as a flour improver in many countries around the world. 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. Using it in flour can make the flour more chewy and elastic, thereby improving the taste of bread, and also has a certain bleaching effect. Many people worry that azodicarbonamide is unsafe. In fact, from the evaluation results of azodicarbonamide by 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., it is safe to use azodicarbonamide in flour according to the standards, and it will not cause cancer.

Azodicarbonamide is used in flour, and its degradation products are not carcinogenic to humans. Some online statements compare it to veterinary drugs, and say that "the toxicity of azodicarbonamide decomposition products exceeds the standard by 90 times", which is completely misleading. Another reason why some people think it is unsafe is that they are worried that companies will use it excessively.

First of all, my country has strict limits on the use of azodicarbonamide in flour. According to the national standard "Standard for the Use of Food Additives" (GB2760-2014), the use of azodicarbonamide is in wheat flour, and the maximum amount is 0.045g/kg. Adding azodicarbonamide to wheat flour, if the amount does not exceed 0.045g/kg, is in line with national standards, unquestionable, and is also part of normal production, without any illegal or irregular issues. If it is used in excess, it is illegal.

Secondly, azodicarbonamide is not something that producers can add at will as some people say. If too little is added, the gluten-enhancing effect is insufficient, and the dough is prone to bursting and cracking when baked. If too much is added, the dough is too chewy, and the bubbles cannot expand when baked, 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 it is possible that some small businesses and workshops may abuse it, it cannot be banned because of this, right? If someone runs a red light or drives under the influence, do we need to ban people from driving? As for some countries not using azodicarbonamide, it is just because of different risk management or better alternatives. A country's ban does not necessarily mean it is unsafe, which is also common in the food industry.

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

As long as you buy flour from a regular brand, you can rest assured.

References:
[1]MCWILLIAMS,M.and MACKEY,AC(1969),Wheat Flavor Components. Journal of Food Science,34:493-496.https://doi.org/10.1111/j.1365-2621.1969.tb12068.x

[2] Liu Liwei, Feng Guohua, Liu Dongtao, et al. Volatile substances of new wheat varieties in the Xumai series[J]. Barley and Cereal Science. 2022, 39(2).

[3] Zhang Yu, Zhang Kangyi, Zhang Guozhi. Comparative study on the flavor of green wheat and wheat[J]. Journal of Henan University of Technology (Natural Science Edition). 2020, (2). DOI: 10.16433/j.1673-2383.2020.02.010

[4] Hu Xigui, Jiang Xiaoling, Wang Yuquan, et al. Comparative study on aroma components of wheat flour from different sources[J]. Hubei Agricultural Sciences, 2017, 56(12): 2332-2336. DOI: 10.14088/j.cnki.issn0439-8114.2017.12.033.

[5] Fu Qiang. Study on volatile components of wheat flour during storage[D]. Jiangsu: Nanjing University of Finance and Economics, 2012. DOI:10.7666/d.y2129126.

[6] Zhu Yin, Teng Jian. A review of the research on volatile components in wheat products[J]. Food Industry Science and Technology, 2023, 44(2): 436-444. DOI: 10.13386/j.issn1002-0306.2022020104. GB/T 1355-2021 Wheat flour GB/T 8607-1988 High-gluten wheat flour GB/T 8608-1988 Low-gluten wheat flour

[7] China Food and Health Information Exchange Center, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention, Scientific Research Institute of National Grain and Material Reserves Administration, etc. Scientific consensus on whole grains and health (2021) [J]. Chinese Journal of Preventive Medicine, 2021, 55(12): 1383-1386. DOI: 10.3760/cma.j.cn112150-20210616-00587.

Author: Ruan Guangfeng, Director of the Science and Technology Department of the Kexin Food and Nutrition Information Exchange Center

Review | Zhang Na, Associate Researcher, Doctoral Supervisor, Peking University School of Public Health