Five aliphatic carbonyl compounds and two methoxypyrazines (MPs) were identified as olfactory dominant green odorants in macerated grape cluster stems of Vitis vinifera var. Cabernet Sauvignon and Chardonnay by a gas chromatography eluate sniffing and dilution analysis technique. Quantitative analysis of these odorants and related volatiles showed that the MP content of the stems was higher than those of the berry or leaf samples, though the aliphatic carbonyl compound content of the stems was not as high as the other parts. The addition of blended stems to the vinification process increased the MP content of the wine, but the identified aliphatic green odorants of the macerated stems were not detected in the wine. Keywords: Grape stem odorant; Cabernet Sauvignon; Chardonnay; methoxypyrazine; stemmy flavor; Vitis vinifera; wine

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Steam treatment of Cabernet Sauvignon, Merlot, Pinot noir, and Muscat Bailey A grape cluster stems eliminated >95% of the extractable methoxypyrazines (MPs) from the stems. Steaming of the Cabernet Sauvignon grape stems increased the levels of extractable flavonoid phenolics, the molecular weight distribution and degree of polymerization of which, as estimated by a gel permeation HPLC analysis, were lower than those of nonsteamed stems in a model must solution. Red wines fermented with steamed stems added showed higher absorbance values at 520 nm than those fermented with nonsteamed stems added and also showed lower MP levels than those fermented with nonsteamed stems. The addition of steamed stems increased the level of flavonoid phenolics detectable in the wines. The levels of phosphoric acid (phosphorus), potassium, and calcium were increased as a result of the addition of stems.

Linalyl-/J-glucoside (LBG), a-terpinyl-0-glucoside (TBG), neryl-0-glucoside (NBG), and geranyl-/?-glucoside (GBG) in sweet potatoes were identified as TMSderivatives from their MS fragmentation patterns and retention times. Amountsof these monoterpene alcohol-/?-glucosides were from 36.9//g/kg sweet potato of LBGto 189.7//g/kg sweet potato of TBG. On the other hand, 75.8 /tg/1 distillation residue of TBGand traces of other monoterpene alcohol-/?-glucosides occurred in the distillation residue. j?-glucosidase (j?-D-glucoside glucohydrolase, EC 3.2. 1.21) in shiro-koji were purified using />-nitrophenyl-/?-glucoside (PNPG), and three active fractions, one major fraction and two very minor fractions, were found. The Kmagainst GBBwas 2.4mMand the Ki against glucose was 7.6 mM.Relative activity in the 20% ethanol solution was 68%. Shiro-koji /?-glucosidases were active on tested /J-glucosides except for LBGand TBG.

Kansho-shochu flavor (KSF) was found in the neutral fraction and was eluted by hexane-ethyl acetate (9 : 1) from a silica gel column. There were several monoterpene alcohols such as linalool, aterpineol, citronellol, nerol and geraniol in the KSF. These monoterpene alcohols contributed to the sensory property of KSF. On the other hand, there were glycosidically bound geraniol and nerol in steamed sweet potatoes. In a model system of shochu mash, geraniol and nerol were transformed into linalool and a-terpineol through heat treatment and into citronellol by the shochu yeast. These results suggest that the monoterpenealcohol glycosides in steamed sweet potatoes were hydrolyzed by glycosidic enzymes in the shiro-koji of shochu mash. Subsequent transformation of the liberated nerol and geraniol into linalool and a-terpineol by the steam distillation process was also indicated.Kansho-shochu (sweet potato spirit) has a very characteristic flavor, fresh sweet potato spirit smelling sweet and very favorable. However, this desirable flavor is lost during