Tuesday, August 20, 2013

Welcome back everyone. I've already talked about all purpose and whole wheat flour before. It's time to continue my topic about whole wheat flour. Let's refresh for a while. :)

All Purpose flour is a type of wheat flour which was made by grinding only from the endosperm of wheat. Whole wheat flour is one type of flour which is made from wheat flour which is composed of 99% wheat grain. It is made by grinding the whole grain of wheat including the bran and the germ. Why does people even bother to include the bran and the germ?

Before answering that question, I'll tell you a short story about wheat flour. At the beginning, people always
remove the bran and the germ during the process of making white flour in order to extend its shelf life. The bran and the germ contain oil and high moisture content which causing oxidation process. The oxidation process can make the flour become rancid and make its shelf life shorter. During the extraction process, about 40% of the original wheat grain was removed. Too bad, by removing the bran and the germ making the white flour lack of nutrition and vitamins. So, with advanced technology, people start to enrich the flour with many vitamins and mineral in order to improve the nutrition content of white flour.

Lately, there have been many researches that showed if the bran and the germ of whole wheat naturally contain many nutrition which can improve the health benefit of the flour itself. Since then, people start to think about whole grain flour. I don't want to talk about eating whole wheat bread causing weight lost, or something like that. I only want to tell a story about this because many of food journals and researches, classified whole grain as a functional food or super food because its  health benefits. Hmm... What is functional food?

Functional Food

In the last decade, preventive medicine has undergone a great advance. Research has demonstrated that nutrition plays a crucial role in the prevention of chronic diseases [Lopez-Varela et al. 2002 in Otles and Ozlem. 2006]. People prefer to do preventive method than get sick and treat it with the medicine. From that fact, we have what we call as functional foods. Functional food is a modified food that claims to improve health or well being by providing benefit beyond that of the traditional nutrient.

Functional food can be whole food or food product with additional or enhanced nutrition which will improve its health benefit.  Functional foods for health are an important part of an overall healthy life style that includes balanced diet and physical activity. But. functional foods are not medicine or "magic bullets" that can make a disease disappear. This foods only will provide many potentially health benefits and the best advice is to include variety of foods on our daily diet.

There are some functional components inside functional foods. Some example of those functional components are :
  • Carotenoid, such as beta carotene, lutein, and lycopene
  • Dietary fiber, such as insoluble fiber, beta glucan, soluble fiber, whole grains
  • Fatty acid, such as monosaturated fatty acids, and polyunsaturated fatty acid
  • Flavonoids, such as anthocianins, and flavanols
  • Isothiocyanates, such as sulforaphane
  • Minerals, such as calcium, magnesium, and selenium
  • Phenolic acidm, such as caffeic acid
  • Sulfides
  • Sterols
  • Polyols
  • Prebiotic, such as Fructooligosaccharides
  • Probiotic, such as Lactobacilli and Bifidobacteria
  • Phytoestrogens, and
  • Vitamins 
Source : http://www.docstoc.com/docs/7273082/Functional-Food-Guide-Pyramid

Wow. so many of them. What are they? I could write a book and not a blog anymore if i explain them one by one. It is complicated. I still remember few years ago, I and my friends suddenly got a headache when we studied this topic for the first time. And I just got another headache.
So, Let's back to the topic. Whole wheat flour. Why does whole wheat flour can be categorized as functional food?

Whole Wheat as a Functional Food

Whole wheat flour is made from whole wheat grains. Whole grains could be an important source of dietary antioxidants, dietary fiber, minerals, and vitamins.

First. Wheat bran cereals could be an  important source of dietary antioxidant. Wheat bran contains phenolic acid which is functioned as antioxidant. Phenolic acid occur naturally in plants. This acid are primarily found in the seeds and skins of fruit  as well. Once ingested, the phenolic acids get absorbed when they reach intestinal tract.  Pheolic acid works to prevent free radical damage in body by protecting the cells in the body.

Second. Whole wheat grain contains pretty high dietary fiber. Based on USDA Nutrient Standard Reference Database, whole wheat flour has higher content of dietary fiber (10.1 grams/100 grams flour) than regular white flour (2.7 grams/100 grams flour). There are 2 types of dietary fiber, which is soluble fiber ( can be dissolved in water, and fermented in colon) and insoluble fiber ( can not be dissolved in water). Both of them are good and needed for body's health.

Wheat bran contains high insoluble fiber.  Insoluble fiber is a fiber (Non-starch polysaccharide) that is found in the cell walls of plants. This fiber can not be digested and absorbed but it will remain in large intestine before passing out in the feces. Even this fiber can not be absorbed, it has great ability to absorb water, and bind the other residues to itself. This process ensuring the feces soft and bulky. That's why, it is good to prevent constipation which is bad to digestive health and can irritate the intestine. Some research said that insoluble fiber helps to balance intestinal pH (acid-alkaline balance), stimulate friendly bacterial flora and fermentation process in large intestine, produce short-chain fatty acid, and reduce the risk of colon cancer.  Wheat bran itself contains 42.8 grams dietary fiber / 100 grams flour. Pretty high, isn't it? To maintain digestive health, it is recommended to consume at least 30 grams dietary fiber/ day for average adults.

Third.  In whole wheat grains, many vitamins and mineral are concentrate in bran and germ. Wheat bran and germ contain high vitamins especially B vitamins  (except vitamins B12), and mineral such as Iron, Calcium, Magnesium, and Selenium. This will cause whole wheat flour has more vitamins and mineral contains than regular white flour. For example : whole wheat flour has 0.502 mg Thiamin (Vit B1)/ 100 grams flour, meanwhile unenriched all purpose flour has only 0.120 mg / 100 grams flour. Whole wheat flour contains 4.957 mg Niacin (Vit B3) / 100 grams flour, meanwhile regular white flour only contains  only 1.250 mg/ 100 grams flour.
Vitamin Content of Whole Wheat Flour
Source : USDA Nutrient Standard Reference Database

Vitamin Content of Unenriched All Purpose Flour
Source : USDA Nutrient Standard Reference Database

Because of this problems, there is a rule that white flour has to be enriched with vitamin B in order to fortified micronutrients that are lost during processing and milling. B Vitamins is very important to support maintenance of mental function, cell growth, and to help the regulation of metabolism and hormone synthesis. B Vitamin, especially B1 deficiency causing a disease named beri-beri.

Whole wheat grains contains a lot of minerals as well, such as Calcium, Iron, Selenium, Magnesium, and Phosphorus. The bran itself contains Iron, Calcium, and Phosphorus. Therefore, whole wheat flour has higher mineral content than regular white flour.

Calcium can reduce risk of osteoporosis. Magnesium can support maintenance of normal muscle and nerve function. Selenium  can help to neutralize free radicals which may damage cell and supports maintenance of immune and prostate health. Iron is part of protein and enzymes which can help carry oxygen in blood and help maintenance of muscle and cell growth in the body.
Mineral Content of Whole Wheat Flour
Source : USDA Nutrient Standard Reference Database

Mineral Content of Unenriched All Purpose Flour
Source : USDA Nutrient Standard Reference Database

 Beside all those good advantage, whole wheat flour still have some disadvantage which are :
  • Whole wheat flour has shorter shelf life than regular white flour. The wheat germ has higher fat content than the endosperm which is causing whole wheat flour has more fat than white flour. That is why without proper storage whole wheat flour can become bad and rancid because of fat oxidation. The shelf life of whole wheat flour is about 6 months-1 year in the freezer if stored in tightly sealed plastic containers and only few months in a cabinet.
  • Whole wheat flour contains phytic acid which may limit the absorption of Calcium and Iron. Phytic acid, in food science world, is one of chelating agent. Chelating agent has a great ability to bind with metal ions such as Calcium and Iron. This ability may help to stabilize food color, aroma, and texture. In whole wheat grains, calcium and iron are bound to phytic acid and make them insoluble and limit their absorption in the body.
  • Whole wheat flour can not form gluten as good as white flour. I think i already explained the reason on my previous post about all purpose flour vs. whole wheat flour.  The bran on whole wheat flour can do some physical disruption of expanded gluten matrix. Bran can cut trough gluten matrix during the kneading or mixing and thus will weaken the gluten structure formed. Beside that, it is possible that there is a competition between bran and gluten protein to absorb water during the process. It will decrease the gluten that formed because gluten formation definitely needs water. Wheat germ contains a substance called glutathione as well. Glutathion is common called as a gluten inhibitor which is able to limit the development of gluten.

Wow. There are a lot of thing that we can talk about whole wheat flour. And there are still a lot more of it. A day won't be enough. Nowadays, we can find a lot of whole wheat product in the market. Bread, pasta, cake, pancakes, cereals, etc. Personally, white bread is still my favorite. But I don't mind changing to whole wheat pasta, or making cake or pancake using whole wheat flour (using a good ratio combination of flour of course). For me, the most important thing is to have a balance and wide variety of food on my daily diet. How about you? :-)

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