How to Use Kestose: In Yogurt, Coffee and Cooking, and Why to Watch Out for “Acidity × Long Heating”

Have you bought kestose but aren’t sure how best to eat it? Is it enough to mix it into yogurt? Will heat change it if you put it in coffee? Can you use it in cooking? You probably have a few questions.

In short, for yogurt and drinks, you can simply add it and stir. There is just one thing to keep in mind when cooking: rather than heat itself, watch out for the combination of “long heating of something sour.”

In this article, you will learn three things:

• How to add kestose to yogurt, drinks and cooking
• Why acidity matters in cooking, even though kestose is described as heat-resistant
• Tips for using it in sour dishes such as sweet-and-sour sauce

First, a note on where this article stands. The product page only says, “Add about one sachet a day to yogurt or drinks, or eat it as is.” It gives no guidance on cooking or heating. The cooking information in this article is Aidaya Shoten’s own summary, based on experiments and papers on fructooligosaccharides, a related group of sugars. It is not based on experiments with kestose alone or with Aidaya Shoten’s products.

The basics: adding one sachet to your own dish is easiest

The basic way to use kestose is to add one sachet (3 g) a day directly to something you are about to eat or drink.

Aidaya Shoten’s Kestose comes in packs of 30 sachets of 3 g. One sachet is a guide for one person, so adding one sachet to your own bowl of yogurt or cup takes the guesswork out of the amount.

If you add it to a whole pot of food, it becomes hard to tell how much one serving contains. So even when cooking, we recommend adding it after serving the finished dish into your own bowl.

In yogurt: just stir it in

For yogurt, simply add one sachet and stir.

1. Put the amount of yogurt you will eat into a bowl
2. Add one sachet of kestose on top
3. Stir lightly with a spoon

It has a mild sweetness, so it is also good when you want a little extra sweetness. Yogurt is sour, but because it is eaten cold, big changes are thought to be unlikely (this is not based on an experiment with yogurt itself). We recommend stirring it in just before eating.

In coffee, tea, milk or soy milk

For drinks, too, just add one sachet and stir.

• Coffee or tea: add one sachet to your cup and stir
• Milk or soy milk: stir it in the same way, whether cold or warm

Many people wonder, “Is it okay in hot coffee?”

A review paper on kestose (Kadota et al., 2020) states that kestose has excellent heat resistance. A study using lab solutions (Le et al., 2022) also showed that kestose tends to be more stable to heat the closer it is to neutral, and less stable as acidity increases.

“pH” is a scale for sourness. 7 is neutral, and the lower the number, the more sour (acidic). According to materials from the US FDA (Food and Drug Administration), lemon juice is 2.00–2.60, milk is 6.40–6.80 and soy milk is 7.00.

Specifically, in a solution at pH 5 and 90°C, it took about 62 minutes for half of the kestose to break down. At pH 7 and 90°C, it took about 134 minutes.

The pH of coffee has been reported as 4.85–5.13 in samples made from light-roast beans (Rao and Fuller, 2018). This is close to the pH 5 used in the lab.

Based on these results, Aidaya Shoten’s view is as follows. It doesn’t take very long to finish a cup of coffee. Compared with a rate where half breaks down over about an hour, big changes are thought to be unlikely during one drink. We have not checked the pH of tea, but it is also drunk over a short time. However, neither result comes from an experiment with the drinks themselves.

Milk and soy milk are close to neutral, so warming them is thought to be one of the less worrying cases.

In cooking: watch “acidity × long heating” more than heat

When cooking, the thing to watch is not heat itself, but the combination of “long heating of something very sour.”

Why does acidity matter if papers describe kestose as heat-resistant? Because sugars like kestose tend to “break apart more easily when acidity is strong and the temperature is high.”

“Breaking apart” here means kestose turning back into sugar (sucrose) and fructose. In experiments, kestose in fructooligosaccharides was observed breaking down into sugar and fructose. What forms is sugar and fructose; this is a change in composition in which the amount of kestose decreases. It is not a finding about effects on the body.

In other words, the closer to neutral, the more stable it is to heat; the stronger the acidity and the longer the high temperature continues, the more it breaks apart. The figure below organizes this idea along two axes.

Another study (L’Homme et al., 2003) also reported that fructooligosaccharides break down mainly under acidic conditions, and more so as the temperature rises.

What an experiment showed: sweet-and-sour pork sauce and simmered dishes

This idea is based on a 2003 study by Atsuko Nakamura of Tokyo Kasei Gakuin University, which looked at how fructooligosaccharides changed in sweet-and-sour pork and simmered dishes.

The study used a commercial fructooligosaccharide: a mix of kestose (three sugar units), nystose (four sugar units) and others, not kestose alone.

The results were as follows.

What was tested	Sourness (pH)	Result
Sweet-and-sour sauce alone (boiled for 4 minutes, then left for 10 minutes)	2.8	Oligosaccharides decreased by about 83%
Sweet-and-sour pork with the other ingredients	4.6	Decrease of 13.5%
Simmered dish (heated for 10 minutes, then left for 10 minutes; the broth reached 100°C)	4.7–5.6	No change

Even with the same sweet-and-sour pork, the amount dropped sharply when only the sauce was boiled, but the decrease stayed at 13.5% when it was cooked with the other ingredients. Adding the ingredients raised the pH by more than 1 (making it less sour), which reduced the decrease. The paper suggests that there was no change in the simmered dish because its broth was only weakly acidic.

The author concluded that paying attention to pH during cooking helps preserve the oligosaccharides, and stated that heating the sweet-and-sour sauce on its own first is not advisable.

That is the research. What follows is Aidaya Shoten’s own summary. Based on these results, we think it is safest, in dishes that use sour ingredients, to add kestose at the end of cooking, or after turning off the heat. The next section explains specifically how to add it.

Where to add it: six situations

Here is a one-page summary of where to add it. In each case, one sachet is a guide for one person.

Yogurt and drinks were covered above. Here we explain the other three.

Homemade dressing

Homemade dressings made with vinegar or lemon are very sour. However, because they are not heated, there is thought to be little concern. In an experiment simulating stomach acid (pH 2.2, 37°C, 30 minutes), breakdown was relatively slow, and it was reported to be fairly stable as long as the temperature was not high. However, a change in which the proportion of sugar rose by about 18% was observed (Nakamura, 2003). This is not an experiment with dressing itself.

• Put vinegar (or lemon juice), oil, salt and so on into a bowl or container
• Add one sachet of kestose along with them
• Mix well (make only as much as you will eat)

When making several servings, add one sachet per person.

Finishing miso soup or simmered dishes

In Nakamura’s experiment, no change was seen in the broth of a simmered dish (pH 4.7–5.6). Miso soup itself was not tested, but since it is a soup without strong acidity like vinegar, big changes are thought to be unlikely. However, if you add it to the pot, it is hard to tell how much is in one serving.

So we recommend serving into your bowl first, then adding one sachet and stirring, rather than adding it to the pot. Since it isn’t simmered in the pot, the effect of heating is also thought to be smaller.

For sweet-and-sour sauce, add it “with the other ingredients” or “after turning off the heat”

Sweet-and-sour sauce, like that used for sweet-and-sour pork, is very sour, so this is a situation to be careful with.

• Don’t add kestose when boiling the sauce on its own first: boiling only the sour liquid was the condition that caused the biggest decrease in the experiment
• When coating the other ingredients: the moisture from the ingredients softens the sourness. Add it after the ingredients are in
• The easiest way is to add it after turning off the heat: turn off the heat at the end and stir in one sachet

For dishes like jam, where sour fruit is simmered for a long time, the same idea applies: adding it after turning off the heat is thought to be the safer choice.

What has not been confirmed

The following could not be confirmed in our research:

• Experiments on how kestose alone changes during cooking
• Experiments using coffee or tea themselves
• Changes in baked goods, such as sweets baked in an oven
• How easily it dissolves, and specific guidance on storage

The cooking information above is only a summary of ideas based on experiments and papers on fructooligosaccharides. It does not mean “if you do this, this will always happen.” When in doubt, the most reliable choice is to add it as is, to yogurt or drinks.

Common questions

Q. How much should I use per day?

We suggest one sachet (3 g) a day of Aidaya Shoten’s Kestose. There is no need to add two or more sachets at once.

Q. What happens if I use too much?

Some warning labels on foods containing oligosaccharides say, “Eating too much, or depending on your constitution or condition, may loosen your stools” (Japan’s Ministry of Health and Welfare list of approved Foods for Specified Health Uses, 1998). Kestose may also loosen your stools depending on your constitution. Start with one sachet a day and see how your body responds.

Q. I’m limiting my sugar intake. Can I use it?

If you have received dietary instructions from a doctor or need to limit your sugar intake, please talk to your doctor before adding it to your diet.

Q. Is morning or evening better?

The product description does not specify a time of day. Add it to yogurt or drinks at whatever time is easiest for you to keep up.

Summary

Here are the three key points of this article:

• For yogurt and drinks, just add one sachet and stir. Adding one sachet to your own bowl or cup makes the serving easy to judge
• In cooking, watch “acidity × long heating” more than heat. No change was seen in the simmered-dish experiment, while boiling something sour (sweet-and-sour sauce alone) is said to break kestose down into sugar and fructose (in experiments with fructooligosaccharides)
• When in doubt, add it to the finished dish. For sweet-and-sour sauce, add it with the other ingredients or after turning off the heat

Something you can do today: try adding one sachet to your morning yogurt or coffee. It is just one small addition to your usual meal, so it is easy to keep up.

Related articles:

• How is kestose made? It starts with sugar, and “trisaccharide” means three linked sugar units
• What’s the difference between kestose and lactic acid bacteria or bifidobacteria supplements? “Food” vs. “the bacteria themselves”
• Fermented foods at every meal: easy pairings with miso, natto, pickles and yogurt

Why not add kestose to your daily diet?

Of the information above, the cooking and heating information is Aidaya Shoten’s own summary based on experiments and papers on fructooligosaccharides. It does not show the effects of Aidaya Shoten’s products or give official usage instructions for them.

Aidaya Shoten’s Kestose contains 100% kestose, the smallest oligosaccharide, made of three sugar units. Each pack has 30 sachets of 3 g. We suggest one sachet a day, added to yogurt or drinks. It has a mild sweetness. Depending on your constitution, it may loosen your stools. If you would like a simple way to start including it in your daily meals, please take a look.

• Kestose 3 g × 30 sachets (one-time purchase)
• Kestose 3 g × 30 sachets (subscription)

Please see the product pages for prices and other details.

Sources

• Nakamura A. “Changes in sugars in sweet-and-sour pork and simmered dishes using fructooligosaccharides.” Bulletin of Tokyo Kasei Gakuin University. No. 43, 49-53 (2003; in Japanese). A mix of kestose, nystose and others was used (not kestose alone). https://www.kasei-gakuin.ac.jp/tkgu_cms/wp-content/uploads/2022/04/43N49.pdf
• Le HP, et al. “Thermal Stability of Fructooligosaccharides Extracted from Defatted Rice Bran.” Foods 11(14):2054 (2022). Results in lab buffer solutions, not in foods themselves. https://pmc.ncbi.nlm.nih.gov/articles/PMC9324758/
• L’Homme C, et al. “Kinetics of hydrolysis of fructooligosaccharides in mineral-buffered aqueous solutions.” J Agric Food Chem 51(1):224-228 (2003) https://agris.fao.org/search/en/records/65dfda3f0f3e94b9e5dcdd22
• Kadota Y, Kitaura Y, Endo A, Tochio T. “Elucidation of the various physiological functions of kestose and efforts toward its practical application.” Journal of the Japanese Society of Nutrition and Food Science. 2020;73(4):123-131 (in Japanese). The authors include members of a company’s R&D department, and some authors receive research funding from that company. https://www.jstage.jst.go.jp/article/jsnfs/73/4/73_123/_pdf
• US FDA, “Approximate pH of Foods and Food Products” (2007; reposted PDF) https://riverstonehealth.org/wp-content/uploads/FDA-Approximate-pH-of-Foods.pdf
• Rao NZ, Fuller M. “Acidity and antioxidant activity of cold brew coffee.” Scientific Reports 8:16030 (2018). Coffee pH (measured in samples from light-roast beans). https://pmc.ncbi.nlm.nih.gov/articles/PMC6207714
• Japan Ministry of Health and Welfare, “On approval of labeling for Foods for Specified Health Uses” (April 15, 1998; warning label for foods with xylooligosaccharides as the functional ingredient; in Japanese) https://www.mhlw.go.jp/www1/houdou/1004/h0415-1.html

This article provides general information about diet. It is not intended to diagnose, treat or prevent any disease. If you have concerns about your health, have a medical condition, or have symptoms that continue, please consult a doctor.