The formation of β-damascenone during shochu manufacture was investigated by quantifying β-damascenone at each stage of manufacturing. Steamed sweet potato has a low level of free β-damascenone (0.02-0.1 µg/g). During fermentation, β-damascenone was produced in small quantities that were degraded by yeast. Thus, the second mash accumulates little free β-damascenone (approximately 17 µg/L). The concentration profile in the fractionated distillate showed that β-damascenone was produced during heating. Most β-damascenone in shochu was formed during distillation, not during steam heating and fermentation. It is suggested that the level of β-damascenone in shochu could be increased by reducing the pH of the second mash and prolonging the distillation period. Sweet potato cultivars differed in total free and hydrolyzed β-damascenone content and there was a strong association between each cultivar and its shochu β-damascenone content. The selection of the sweet potato cultivar is important for determining the quantity of β-damascenone in a shochu brew.
Nu c l e a r ma g n e t i c r e s o n a n c e NMR I n f r a r e d I R Ul t r a v i o l e t UVMi c h a e l i s c o n s t a n t K� I n h i b i t i o n c o n s t a n t K� Di s s o c i a t i o n c o n s t a n t K� Mo l e c u l a r we i g h t M�Bo i l i n g p o i n t b p Me l t i n g p o i n t mp I s o e l e c t r i c p o i n t p I Ra t e o f f l o w ( Re t a r d a t i o n f a c t o r ) R�Re t e n t i o n t i me t� Estimation of the mechanism for cis and trans rose oxides formation in sweet potato shochu.Kazunori Takamine Cis and trans rose oxides (rose oxide) detected in sweet potato shochu were 0.8 ~ 4.6μg/L and 0.3 ~ 1.9μg/L, respectively. The aroma threshold value of rose oxide in a 25% ethanol solution and sweet potato shochu was 0.35μg/L and 14μg/L, respectively. The aroma of rose oxide was evaluated as a sweet, floral, and rose-like flavor. Rose oxide was not included in a first moromi-mash and a sweet potato. Linalool, nerol, geraniol, and α -terpineol were not converted to rose oxide though citronellol was in the model moromi (pH4.2, 15 % alcohol) incubated for five days at 30 ℃ .The distillation process and the pH 3.5 or less in the model moromi promoted conversion from citronellol to rose oxide. It was found that koji mold and Saccharomyces cerevisiae were not able to convert citronellol to rose oxide. The bioconversion of citronellol from geraniol was not koji mold but S. cerevisiae. Our results indicated that citronellol bioconverted from geraniol by S. cerevisiae during the fermentation process was further converted to rose oxide by an acid-catalyzed reaction. Also, we confirmed that this chemical conversion was promoted by distillation. Key words:
The interaction forces between a platinum dichloride complex and DNA molecules have been studied using atomic force microscopy (AFM). The platinum dichloride complex, di-dimethylsulfoxide-dichloroplatinum (II) (Pt(DMSO)Cl), was immobilized on an AFM probe by coordinating the platinum to two amino groups to form a complex similar to Pt(en)Cl, which is structurally similar to cisplatin. The retraction forces were measured between the platinum complex and DNA molecules immobilized on mica plates using force curve measurements. The histogram of the retraction force for λ-DNA showed several peaks; the unit retraction force was estimated to be 130 pN for a pulling rate of 60 nm/s. The retraction forces were also measured separately for four single-base DNA oligomers (adenine, guanine, thymine, and cytosine). Retraction forces were frequently observed in the force curves for the DNA oligomers of guanine and adenine. For the guanine DNA oligomer, the most frequent retraction force was slightly lower than but very similar to the retraction force for λ-DNA. A higher retraction force was obtained for the adenine DNA oligomer than for the guanine oligomer. This result is consistent with a higher retraction activation energy of adenine with the Pt complex being than that of guanine because the kinetic rate constant for retraction correlates to exp(FΔx - ΔE) where ΔE is an activation energy, F is an applied force, and Δx is a displacement of distance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.