抹茶の神話と、緑茶の137倍の抗酸化物質が含まれているという主張

The methanol extraction of the powder vs the water extraction of the green tea may not be as bad a comparison as you would first think.
The water extraction of the green tea is what the person actually consumes, so it is easy to then prepare this sample for the chromatography and assess what is present.
The matcha powder is fully consumed, so it needs to be understood what is present in the powder. To see what is present, the powder needs to be prepared in such a way that the chromatography method can detect what compounds are present. This usually takes form in a methanol extraction.
The methods and comparison are fine, the only caveat that should be included is that while there may be 137x the compounds present in match vs green tea, there is the very real possibility (and high probability) that the body would not be able to extract that full amount.

Hi Marc, First of all, you do need to be careful about generalizing. Ichibancha or first flush and nibancha or second flush, refers only to the specific flush, and says nothing about cultivation or production. Given the exact same amount of exposure to sunlight and the same tea field, I would say that first flush leaves have more of all components. If you shade the leaves, there will be less exposure to sunlight so more theanine and less catechin. Most farmers allow their second flush to grow longer (resulting in more sunlight exposure) to get a larger crop yield, so the tendency is for more catechin. But I would say the second flush also has less caffeine.

Hi Ian,
Is it accurate that Shincha/Ichibancha sencha has less caffeine, less catechins but higher amino acids (I assume that by higher amino acids, people refer mainly to L-theanine ) than Nibancha harvested sencha ?

My understanding is that catechins are actually produced from L-theanine with the help of direct/full sun exposure. Since Shincha/ichibancha means spring harvest, such leaves have seen little sun exposure, so I’d expect the claim of higher L-theanine and lower amount of catechins to be accurate. However, I’m not so sure about lower amount of caffeine. The reason I say that, is because gyokuro which generally has higher amounts of L-theanine than sencha, also has higher amounts of caffeine than sencha.

As far as I know the effects of green tea relies on the ratio of three main components : theanine, catechins and caffeine.

I’m looking to find the general ratios of the above in both ichibancha and nibancha. Off the top of my head, as far as Nibancha, I’d assume lower amounts of L-theanine, higher amounts of catechins and lower amounts of caffeine.

Am I mistaken ?

Many thanks

Hi Marc, I am not a food scientist, so I am speaking only with knowledge as someone who has read a lot about this in Japanese. “Sencha Nagashima” is almost certainly a product name, not a type of sencha, so I am going assume that the “high fired” term you use is 火入れ in Japanese, hi-ire, what we call “green roasting” here on Yunomi, and a process where you heat sencha in a roaster on low heat for a short time so as not dry it out more without actually roasting it. This has the effect of reducing moisture from unrefined tea leaves (aracha) at 5% to 1-2%, imparting a sweet toastiness without removing too much of the vegetal flavor, and allows for storage of 6-18 months much less decline in quality.

I do know that roasting the leaf to the point of hojicha reduces the amount of caffeine and reduces the catechin in the leaf. How much green roasting reduces this is something I do not know though.You can see the general difference between sencha and hojicha here: https://yunomi.life/blogs/japanese-tea-guide/japanese-tea-nutrition-chart

I’ll take a look to see if any Japanese research has been done on this hi-ire process.

This question is about Japanese sencha :

Mood wise I benefit from most first-flush sencha, but one ; sencha Nagashima which is a high-fired tea. I suspect this lack of effect has to do with it being high-fired. I’ve seen an HPLC analysis of that tea and it’s been found to have a high amount of polyphenols – though this is a bit vague as there are many types of polyphenols present in sencha.

Do you think the high-firing process causes polymerization ? This might explain why it’s been found to have a high amounts of polyphenols and why I don’t get the mood benefit from this one tea.

This question is about Japanese sencha.

I’ve been drinking sencha for 9 years now. I drink sencha for the overall experience and the effect it has on my mood and overall health. Most sencha improve my mood.

One type of sencha however, doesn’t produce that effect – it is high-fired sencha (i.e. Sencha Nagashima). I’m wondering why that is ? I’ve seen an HPLC analysis of that tea and it has a high amount of polyphenols – though, that is somewhat vague, as there are many types of polyphenols in sencha.

I’m pretty sure it has to do with it being high-fired where other sencha teas I drink aren’t.

Could the high-fired process cause polymerization ? That might explain why it has a high amount of polyphenols and why I don’t benefit from that tea.

Thank you