green pepper
ingredient / ingredient-green-pepper-ja
ピーマン / green pepper (Japanese piman) / Capsicum annuum
Green pepper is the fruit of a sweet-pepper cultivar of Capsicum annuum called (piman) in Japan. Research has examined how bitterness, astringency, and green aroma overlap perceptually, and how bitterness changes when combined with seasonings that include egg yolk.
On this page (6 sections)
Reading the bitterness
The Japanese piman is the fruit of a sweet-pepper cultivar of Capsicum annuum. It is spoken of as the archetypal thing children dislike, yet what its bitterness actually comes from is a surprisingly recent question. A 2012 announcement by the researchers involved records isolating quercitrin from a compound detected only in the conventional cultivar, and states that on its own it tasted astringent. They then explain that what was perceived as the bitterness of piman was the astringency of quercitrin combined with the aroma of 2-isobutyl-3-methoxypyrazine. What goes by the name of bitterness is written here as an overlap of taste and aroma.
The softening side has been measured too. Adding egg yolk or egg white to a liquid made by grinding raw piman and mixing it with water at 1:3, and having 20 people rate it on a 7-point scale, the yolk lowered the bitterness significantly more than the white. In the same system, yolk mixed with vinegar and left for about 1 day was significantly more effective than yolk alone. The kitchen sense that mayonnaise works has a line drawn to it from the compositional side.
How well it works is not decided by the formulation alone. When egg-yolk mayonnaises differing only in their emulsion state were added to the piman liquid and rated by 20 people, the smaller particle size corresponding to factory production lowered the bitterness significantly more than the larger size corresponding to a hand-made one. All of these, though, are summaries of company announcements, with the amounts added and the exact figures unconfirmed, and what was evaluated was piman liquid rather than a dish. They cannot be carried straight over to a plate of stir-fry.
Sources for this overview
タキイ種苗×お茶の水女子大学 共同研究成果「ピーマンの苦味成分」を解明
Checked for this overview: The researchers’ announcement that quercitrin alone tasted astringent and that it was perceived as bitterness when combined with the pyrazine aroma
Checked for this overview: Egg yolk lowered the bitterness significantly more than egg white / Acid-denatured yolk was significantly more effective than yolk alone / The small emulsion particle size lowered the bitterness significantly more than the large one
Other names: Capsicum annuum (la, identification medium)
Structured claims — open a section to read each claim's confidence, evidence and limits
Sensory (6)
Scope: Juice extraction, compositional analysis, and taste evaluation of a conventional cultivar and 「こどもピーマン」 (Kodomo Piman).
Note: On the product-release page, the number of tasters, scale, concentration, and statistical values for the taste evaluation are not given. This is not treated as the sole bitterness mechanism for green pepper in general.
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ingredient-green-pepper-ja —has_perceived_bitterness_associated_with→ "The developers' own 2012 announcement describes isolated quercitrin alone as astringent, and states that the astringency of quercitrin combined with the aroma of 2-isobutyl-3-methoxypyrazine was perceived together as the bitterness of green pepper."Scope: Green pepper liquid evaluated by 20 Kewpie researchers (12 men, 8 women).
Note: Figure 1 in the corporate-release abstract shows mean values, standard deviations, and significant differences at the 5% level, but the amount added and exact numerical values are not given. This is not a direct comparison of a cut green pepper dish.
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ingredient-green-pepper-ja —has_perceived_bitterness_suppressed_by→ "Egg yolk. In a 7-point sensory evaluation by 20 panelists of a liquid made by crushing raw green pepper and mixing it with water at 1:3, with egg yolk or egg white added, the bitterness-reducing effect was significantly higher for egg yolk than for egg white."Scope: A comparison of egg-yolk-type mayonnaise, varied only in emulsion state, added to green pepper liquid.
Note: Figure 2 in the corporate-release abstract shows mean values, standard deviations, and significant differences at the 5% level, but the particle size, amount added, and exact numerical values are not given. This is not a comparison of commercial product brands.
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ingredient-green-pepper-ja —has_perceived_bitterness_affected_by→ "The emulsion particle size of egg-yolk-type mayonnaise. In a sensory evaluation by 20 panelists of mayonnaise added to green pepper liquid, the small particle size equivalent to factory production showed a significantly higher bitterness-reducing effect than the large particle size equivalent to homemade production."Scope: A 7-point sensory evaluation by 20 panelists of acid-denatured egg yolk and egg yolk added to green pepper liquid.
Note: Figure 3 in the corporate-release abstract shows mean values, standard deviations, and significant differences at the 5% level, but the formulation of egg yolk and vinegar, the amount added, and exact numerical values are not given. This is not a recommendation for a home procedure of letting it sit for about 1 day.
Show data
ingredient-green-pepper-ja —has_perceived_bitterness_suppressed_by→ "Acid-denatured egg yolk. A sample made by mixing egg yolk with vinegar and letting it sit for about 1 day showed a significantly higher bitterness-reducing effect on green pepper liquid than egg yolk alone."Scope: Bitter gourd and green pepper. Sensory evaluation of samples heat-cooked with mayonnaise or edible vegetable oil (the number of people and the method are not in the abstract), and evaluation of bitterness by a taste sensing system for the group with mayonnaise and the group without. Limited to a conference abstract
Note: The abstract gives no panel size, statistics or numbers. It describes bitter gourd and green pepper without separating them. The taste sensing system values are not to be equated with human sensory evaluation. The mechanism of adsorption was, at the time of the abstract, a speculation still being confirmed. This is research by a company (a mayonnaise manufacturer). As a conference abstract, it has not been peer reviewed. The samples used mayonnaise at the stage of heat cooking; it was not added afterward to a finished dish.
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ingredient-green-pepper-ja —has_perceived_bitterness_suppressed_by→ "Heat cooking with mayonnaise. Samples of bitter gourd and green pepper heat-cooked with mayonnaise had reduced bitterness in sensory evaluation compared with samples heat-cooked with edible vegetable oil. The bitterness values from a taste sensing system (an electronic taste sensor) were also clearly lower in the group with mayonnaise than in the group without. The authors speculate that emulsified particles in the mayonnaise may adsorb the bitter components."Scope: Green pepper (50 g stir-fried, and a liquid made by adding an equal amount of water to green pepper, grinding it in a food processor and filtering it). The sensory evaluation was by 20 people, comparing deep-roasted sesame dressing against a control of equivalent salt on stir-fried green pepper. A company's (Kewpie's) own dressing. Limited to a conference abstract
Note: The abstract gives no sensory scores or test method. The control was an equivalent amount of salt, not water, so the effect of saltiness is subtracted. The abstract states that which part of the dressing (oil, vinegar, egg yolk or sesame) was effective has not been examined. The taste sensing system values are not to be equated with human sensory evaluation. Seasoning with the dressing after stir-frying is close to the situation of adding it afterward to a finished dish. As a conference abstract, it has not been peer reviewed.
Show data
ingredient-green-pepper-ja —has_perceived_bitterness_suppressed_by→ "Deep-roasted sesame dressing. A sample in which 50 g of green pepper was stir-fried and then seasoned with 7.5 g of deep-roasted sesame dressing had significantly lower bitterness than a control seasoned with an equivalent amount of salt, in a sensory evaluation by 20 people. Instrumental analysis also showed reduced bitterness and odor in the stir-fried green pepper. When the dressing was added to a liquid made by adding an equal amount of water to green pepper, grinding and filtering it (raw), the bitterness by the taste sensing system (especially bitter aftertaste) was lower and the characteristic odor of green pepper was significantly reduced (2-isobutyl-3-methoxypyrazine is listed among the keywords of the abstract)."