Showing posts with label Food tech. Show all posts
Showing posts with label Food tech. Show all posts

Saturday, September 21, 2013

Baking Powder vs. Baking Soda

10:11 PM by Selly No comments
Few weeks ago, someone asked me what is the difference between baking soda and baking powder? Why does people need it to bake a cake and cookies? Why do some recipes need baking powder only, but the others need both of them? How does actually this thing work? Hmm... good question. Yeast, baking powder and baking soda, all of them are leavening agent which are needed to make the cake, bread, and the cookies rise up in volume during baking process.

Leavening agent is a substance which is causing expansion of dough and batters by the release of gasses within such mixtures, producing baked products with porous structures (Encyclopedia Britanica, 2013). Yeast is the most popular leavening agent, especially for making breads products. Based on fermentation process, yeast will use fructose, glucose, and other simple sugar that are present in the dough ingredients as its food. Yeast's enzymes will break down the sugar and produce alcohol and carbon dioxide as by-product. The alcohol will evaporate during the baking process. Meanwhile, the carbon dioxide will trapped inside the dough and cause the bread to rise. Yeast fermentation need time to leaven the bread. Meanwhile, cake and cookies need something fast. That's why, we have chemical leavening agents which are baking powder and baking soda.

Baking Soda

Baking soda is one of chemical leavening agent which is actually chemically named bicarbonate (HCO3‑). 
This bicarbonate is usually bound with another molecule such as sodium or pottasium and ammonium. In the market, it usually present as Sodium bicarbonate (Mostly Natrium bicarbonate or NaHCO3). With the presence of water, Sodium bicarbonate will react with any acidic material and release Carbon dioxide gas (CO2). The heat from the baking process will be the catalyst to speed up the reaction process.

NaHCO3 + HCl ----> NaCl + H2CO3
( H2CO3 is called Carbonic acid and this acid is unstable so it will automatically separate into water and carbon dioxide)

  H2CO3 ----> H2O + CO2

Because it is an acid-base reaction, in order to be able to produce gases, baking soda definitely needs acid. With the presence of acid, baking soda can react  and produce gas during the baking process. That's why, most of the cake recipes that use acidic ingredients will need baking soda as the leavening agent. Acidic ingredients that can induce the reaction of baking soda include : Cream of Tartar (COT), lemon juice (or other fruit juice), yogurt, buttermilk, vinegar, molasses, etc. The more acidic the ingredients, the more baking soda that are needed. and This is a diagram of the acidic level of some common ingredients of baking product. But be careful. Too much baking soda can cause the product has a soapy and bitter taste.
Source : Potter, J. 2010

Baking Powder

Nowadays, in modern baking process, baking powder is more famous than baking soda. Baking powder is actually a chemical leavening agent which is contained baking soda, dry acid, and starch. By adding some water, baking powder become wet  and will produce carbon dioxide gas. Baking powder doesn't need additional acidic ingredients on the batter because it has dry acid on baking powder itself.
Baking powder contain starch as well to increase the shelf life by absorbing moisture and preventing sodium bicarbonate and dry acid inside baking powder react prematurely. That's why, baking powder can always be substitute by mixing 1/2 tsp Cream of Tartar + 1/4 tsp baking soda + 1/4 tsp corn starch for each tsp baking powder that are needed on the recipe.

In the market, there are 2 different type of baking powder which are single acting and double acting baking powder. Single acting baking powder contain only 1 acid and 1 base and will cause only 1 reaction. This single acting baking powder will react and cause a bubble soon after all the dry and wet ingredients are mixed. So, if the food is not baked as soon as possible after all the ingredients are mixed, we will lose all the bubbles and the food becomes flat. Single acting baking powder is not common on the market. Commercial baking powder mostly are double acting baking powder. Double acting baking powder contain 2 acid and will cause 2 step of acid-base reaction during the whole process. Fist acid is fast-acting acid which will react with presence of liquid. That's why, the first step will happen during the mixing process. The example for this kind of acid are : cream of tartar and calcium acid phosphate. Meanwhile, the second step will happen during the baking process because the second acid is slow-react acid or heated-activated acid. The example of this kind of acid are : sodium aluminium phosphate, sodium aluminium sulfate, and sodium acid pyrophosphate. This double acting baking powder are commonly available on the market and more reliable than single acting baking powder.

I found this interesting video on youtube about baking soda and baking powder.


Why do some recipes need both baking soda and baking powder?
Hmm.... It's a good question. For example : buttermilk muffin would need both baking soda and baking powder. Why? There are many explanation that i found on the internet. Most of them said that is because of the acid. If the recipe is a bit acid or contain a lot of acid ingredients but you don't want your muffin has sour taste because it contains too much acid, than baking soda is needed to neutralize the acid ingredients. Meanwhile, baking powder will be functioned as leavening agent. That's the theory. Now, let's play with them. :)

My small experiment
Yesterday, I tried to make buttermilk muffin. This is the original recipe from Allrecipes. From one recipe, I divided the batter into 12 portion. Each portion is enough for 1 normal muffin or 2-3 mini muffins. I took 4 portion out of it, and gave a different treatment for each of them. First treatment : no leavening agent at all. Second treatment : only baking soda. Third treatment : only baking powder. Fourth treatment : baking soda and baking powder. I just want to see the difference between all of them. (I made bacon muffin from the rest of the batter) Of course I divide the amount of leavening agent into 12 as well. It was not easy tough. After mixing well all those different the batter, I poured them into small muffin tin and bake them. Same temperature, same time. And this is the result.


1 : No baking soda and baking powder
2 : Baking  powder only
3 : Baking soda only
4 : Both baking soda and baking powder.

Like I was expected, buttermilk muffin without baking soda and baking powder will come out flat and sour. Same thing with buttermilk muffin with baking powder only. It will rise and leaven but still sour because the acid from buttermilk was not neutralized with baking powder. The buttermilk muffin number 4 rise well and doesn't have sour taste like buttermilk muffin number 1 and 2. But, buttermilk number 3 was not like I was expected. I was expecting that muffin with baking soda will a little bit flat and not sour because I was hoping the acid from buttermilk will react fast with baking soda and the the muffin will lose the gas during baking process because of the fast reaction of baking soda. But my muffin leavened pretty well. The taste of the muffin turned out not like i was expected as well. It is bitter and soapy. I think I gave too much baking soda for my batter.

One more thing that make me curious. The color of the muffin. Why does muffin with baking soda has darker color than muffin without baking soda? As we can see on the pictures above, the muffins number 3 and 4 are are darker and more brown than muffins number 1 and 2. What did baking soda do during the baking process? After hours looking for the answer, It turned out that baking soda increase alkalinity on the batter and enhance the maillard reaction during the baking process.

Maillard reaction is one of non-enzymatic browning reaction that happened  when amino acid from protein and simple sugar break down and recombine into another components which will give brown color and unique intense flavor and aroma. This reaction is usually triggered by heat. Simple example for this reaction is browning process on cookies, cake, bread, roasted chicken, etc. There are a lot of factors that can affect maillard process, including pH or the acidity of the ingredient. Maillard reaction will accelerate in alkaline environment (pH >7) and acidic environment (pH <7) can inhibit the reaction. Baking soda is alkaline and I know my muffin is alkaline as well. (I was adding too much baking soda as well. It was proved with the soapy and nasty taste). That's why the color of the muffin number 3 (only using baking soda) is very brown. Meanwhile, muffins number 1 and 2 (without baking soda) are very pale because the acid from buttermilk inhibit the browning reaction. 

Well, there are many fun facts about baking soda and baking powder. I personally would like to have both of them on my kitchen. They're quite handy for a lot of thing, not only for baking cake. Even baking soda can be used for a small science adventure with the children. For making volcano eruption for example. But make sure to store and keep them in a dry place to prevent premature reaction in the storage. There is an easy way to test the effectiveness of baking powder. Just mix 1 tsp baking powder with 120 ml warm water. If there're any bubbles  then the baking powder is still good. For baking soda, just mix 1/4 tsp baking soda with 2 tsp vinegar and see if there's any bubbles appear immediately.  Have fun in the kitchen. :-)


References :

Tuesday, August 20, 2013

Little Secrets about Whole Wheat Flour (All Purpose Flour vs. Whole Wheat Flour Part 2)

10:56 AM by Selly No comments
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? :-)

References :

Tuesday, August 13, 2013

All Purpose Flour vs. Whole Wheat Flour

2:48 PM by Selly 1 comment
Today, I want to talk about something geeky. It's about wheat flour. Few weeks ago, my friend asked me if she can substitute all purpose flour with whole wheat flour for her cake. I'm pretty sure, a lot of bakers can give her a good answer. But some of us maybe do not quite sure about it or maybe never even heard about whole wheat flour. It tickles me for days. I decided to do some small research, read my old books, and open my university final essay. Oh yeah. I learned about this kind of thing back than in university. But it was like 7 or 8 years ago and I haven't touched it again for that period of time. I'm a little bit rusty now.  But let's see how far i can remember and refresh my memory. First, let's talk about wheat flour. :)

Wheat Flour

Wheat flour is product that is made from wheat by removing the brown surface coating (the bran) and the
embryo (the germ) and reducing the particle size (by grinding and sifting) into a fine product. It can be used and even the largest ingredients for many kind of baked product, for example, bread, cake, biscuit, cookies, crackers. Wheat flour has a very important protein which is called gluten. Gluten plays very important role to give specific characteristic for each baked product. It gives elasticity and extensibility of the product.

Gluten is formed by 2 kinds of protein which are gliadin and glutenin. Gliadin will give elasticity to the dough, and glutenin will give firm and tough texture at the dough. With presence of water and kneading process, gliadin and glutenin will make crosslinks and bond together to create a stretchy, net-like matrix.  The protein content and the quality of gluten in flour is dependent on the type of wheat that were used. Therefore,  based on protein and gluten content, basically there are 3 types of flour which are :
  • Strong flour (made from hard grain with high protein contents that give elastic but inextensible gluten. The protein contents of strong flour is usually in the range 10.5-14.5%. This kind of flour is perfect for making bread)
  • Medium flour (made from wheat with medium protein contents or mixed from hard and soft wheat. The protein content of medium flour is usually in range 8.5-10.5%.)
  • Weak flour (made from wheat with lower protein contents that give more extensible but less elastic gluten. The protein contents of soft flour is usually less than 8.5%. This flour is perfect for biscuit productions)
As you know, nowadays there're a lot of type of flour in the market. Not only soft, medium and hard flour anymore. We can find self rising flour, cake flour, all purpose flour, semolina, durum, pastry flour, whole wheat flour, bread flour, gluten flour, bleached flour, and instant flour. The most common flour that i can find in the store nearby are all purpose flour, self raising flour, whole wheat flour, and instant flour for cake and for bread. I don't want to talk about self raising and instant flour. They already contained some raising agent such as baking powder or yeast. Let's talk about all purpose flour and whole wheat flour. Nowadays, they are the most common type of flour. What are they?

All purpose flour

All purpose flour is the most widely used flour. It comes from the finely ground part of the wheat kernel called the endosperm. The endosperms were separated from the bran and germ during milling process.

All purpose flour is made from blend of high gluten wheat and low gluten wheat so it has protein content in range 9-12% (depend on the brand). That's why all purpose flour can be categorized as medium-strong flour. All purpose flour can be used universally for a wide range of food products such as yeast bread, cakes, cookies, biscuit, pastry, doughnut, and many thing else.

Is all purpose flour the same with regular plain wheat flour? The answer is yes, it is. Regular plain wheat flour have protein content in range between 9-12% like all purpose flour. In here, Netherlands, I won't be able to find flour with "All purpose flour" written on its package. I only can find patent tarwebloem (fine wheat flour) or volkoren tarwebloem (whole wheat flour). Or self rising flour, bread flour, and cake flour. But i always buy patent tarwebloem which i consider it as all purpose flour because it is regular plain flour with protein content 11 grams/100 grams flour. I will use it for making any kind of food such as cake, cookies, doughnut, bread, even for thickening agent in cream soup.

Whole Wheat Flour

Whole wheat flour is one type of 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. That's why it is called whole wheat flour. Because whole wheat flour contains all part of the grain, its color is darker and more brownish than regular plain flour.


I tried to take a picture of both type of flour. The left one is all purpose flour, and the right one is whole wheat flour.  As we can see, whole wheat flour has some brownish particle mixed in the flour. That stuff are wheat bran. The bran can not be grained as well as the endosperm. That's why it gives whole wheat flour a rougher texture than all purpose flour. 

What's the difference between all purpose and whole wheat flour?

Based on USDA Nutrient Standard Reference Database, whole wheat flour has higher protein content than all purpose flour. It has 13.21 grams protein/ 100 grams flour meanwhile all purpose flour only has 10.33 grams protein/ 100 grams flour. So, does it mean that whole wheat flour has higher gluten than all purpose flour? The answer is NO. Whole wheat flour has lower gluten than all purpose flour. Hey, how come?? 

Back to the definition and the raw material of each flour. Whole wheat flour is made from whole grain including the bran and the germ. The bran and the germ itself contain some protein. But all purpose flour is made only from the endosperm.  Let's consider that about 3 grams protein content difference are from the bran and the germ. So basically, the endosperm has the same protein content, which can be assumed they both has same gluten content. But why whole wheat flour product can not form gluten as well as all purpose flour product? Once again, it is because of the bran and germ. 

Before we're talking about bran, let's back to how gluten formed for a while. Gluten is formed from 2 proteins which is gliadin and glutenin which will interact with presence of water during stirring or kneading process. There are some factor which can affect gluten formation. One of them is the presence of bran and germ. The bran 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 need water. 

Meanwhile, wheat germ contains a substance called glutathione. In world of baked product, glutathion is common called as a gluten inhibitor because it can limit the development of gluten. That's why,  it is always suggested to add bread flour or gluten flour to make whole wheat bread to keep the texture of the bread. 

I did a small experiment on my kitchen using all purpose and whole wheat flour. I made 2 recipes of orange muffins. One was using all purpose flour and the other was using whole wheat flour (I was using whole wheat flour only 3/4 part of total flour and using all purpose flour for the rest). I was using the exact same recipe for both muffins except the type of flour. 



This is the result. The muffin on left side on both pictures is made using all purpose flour (let's call it muffin A) and the other is made using whole wheat flour (let's call it muffin B). The texture of muffin A is softer than muffin B. Inside and outside. The color of muffin A is lighter than muffin B. The most interesting is the difference of their shape. Muffin A is more compact than muffin B. As we can see in the picture, the top part of muffin B is wider than muffin A. It seems that the batter spreading too much during the baking process. I think it is because the gluten that formed in muffin B is not strong enough to hold the shape of the muffin like in muffin A. Muffin B is crumbly a lot as well even though it is heavier and more dense than muffin A.

I did some preference test as well. I asked my friends and my family to try them and compare which one is they like more. Most of them choose muffin A because it is softer than muffin B. I personally prefer muffin B than muffin A because for me the bran that presence in muffin B give a unique taste and texture in my mouth. But overall they are edible, acceptable, and taste great. 

So, answering the very first question. Can we substitute all purpose flour with whole wheat flour? Yes we can. But it would be better if we do not substitute the whole part of flour with whole wheat flour. It is needed in order to keep the texture and shape of the product. Some reference said substitute 70% and add the rest with all purpose flour or gluten flour. Meanwhile, other reference said 50:50 is good. And it is depend on the type of baked product. Too bad i do not have time and material to do all those experiment. I was thinking to do the experiment with dinner roll and playing with the amount of whole wheat flour for my muffin. But this is good enough to satisfy my curiosity. :)

Why  does whole wheat flour exist? What is the advantage adding bran and germ into the flour?

See you on part 2 with the answer :)

References : 




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