Umami Intensity Research Articles

干ししい茸の水もどし条件について

Dried Shiitake mushrooms rehydrated under various conditions were cooked and erences between the cases of Donko and Koshin varieties, the cooked mushrooms which soak ed at 5°C for 5h or more and at 25°C for 5 to 15h were preferable. On the whole, the mushr ooms soaked at 40°C were evaluated to be not preferable, however, some of them soaked for a short time were relatively preferable. The impression for taste of the cooked Shiitake was correlated with the intensities of umami and bitterness. The increase of umami h eightened the impression score for taste. On the other hand, bitterness provided bad effec t on its score. The score for intensity of umami in cooked dried Shiitake was correlated with the concentrations of 5'-GMP and glutamic acid. The content of hydrophobic amino ac ids in dried Shiitake cooked after long time soaking at high temperature were enough to cause bitter taste. Since the mushrooms, which generated much 5'-GMP and contained le ss hydrophobic amino acids, were scored highly for taste and consequently gained a good overall estimate, it was suggested that the soaking for a shorter time at lower temperature was desirable. However, the one soaked for too short time was not thoroughly reh ydrated, so scored lower points for texture and consequently not prefered. (Received Jul. 7, 1988)

The effects of phosphatase treatment of yellowtail muscle extracts and subsequent addition of IMP on flavor intensity.

The effects of phosphatase treatment of yellowtail Seriola quinqueradiata muscle extracts and the subsequent addition of inosine 5'-monophosphate (IMP) were investigated to elucidate the role of IMP as a flavor substance in fish meat. The treatment of extracts from the fresh white muscle with acid phosphatase resulted in a remarkable decline of flavor intensity (umani, thickness, sourness, fresh fish flavor, and overall taste quality). IMP added back to the enzyme-treated extracts restored the flavor intensity, depending on the concentrations. There was a slight increase in umami intensity at 0.125μmol/ml of IMP and in thickness intensity together with the umami at 0.25μmol/ml. The addition of IMP at 0.5μmol/ml resulted in significant recoveries of all flavor attributes. When 2μmol/ml of IMP was added, the extract showed the maximum flavor intensity; higher levels of IMP did not enhance the intensity any more.

MEASUREMENT OF THE RELATIVE TASTE INTENSITY OF SOME L‐α‐AMINO ACIDS AND 5′‐NUCLEOTIDES

SUMMARY— Intensity of glutamate‐like and/or inosinate‐like taste (umami in Japanese) of various flavor amino acids and flavor nucleotides was studied using sensory analysis and always found proportional to that of monosodium glutamate (MSG) and disodium 5′‐inosinate (IMP), respectively. By application of this fact to a previously obtained equation expressing the relationship between the taste intensity of MSG‐IMP mixture and that of MSG alone, the intensity of umami of the mixture of any flavor amino acids and nucleotides could be expressed as an elementary equation: y = u +γ uv, where u and v are the concentrations of amino acids and nucleotides in terms of the concentrations of MSG and IMP, respectively, in the mixture; y is the equivalent concentration of MSG alone; and γ is a positive constant. Interrelationships within each group of substances were additive.