RESUMO
AIMS: Pit mud is essential for the quality and yield of Chinese Luzhou-flavoured liquor. A reliable and fast method based on the use of microbial indicators combined with environmental factors coupled with metrology tools is needed to discriminate and classify different maturity levels of Luzhou-flavoured pit muds. METHODS AND RESULTS: Firmicutes, Bacteroidetes, Actinobacteria, Lactobacillus, Bacillus, Methanosarcina, Methanocorpusculum, Methanoculleus and Clostridium kluyveri were microbial indicators in Luzhou-flavoured pit muds. They were detected by real-time quantitative PCR. Environmental factors investigated included moisture content, pH, total acid and ammonia nitrogen. Principal component analysis (PCA) and partial least square-discriminant analysis were employed to explore the structure of the data and construct discrimination and classification models by reduction in the data dimensionality. Pit muds were distinguished and classified as new, trend to-be aged and aged. Moisture content and pH were significantly negatively correlated with new pit mud, while pH, total acid, amino nitrogen, Firmicutes, Bacteroidetes, Actinobacteria, Methanosarcina, Methanoculleus and C. kluyveri were significantly positively correlated with aged pit mud. CONCLUSIONS: Microbial indicators combined with environmental factors coupled to metrology tools can reliably and quickly discriminate and classify different maturity levels of Luzhou-flavoured pit muds. SIGNIFICANCE AND IMPACT OF THE STUDY: Modern techniques and metrology tools verified the correctness of the traditional sensory evaluation used in controlling the quality of pit mud, and will contribute to distinguishing different maturity levels of Chinese Luzhou-flavoured pit muds.
Assuntos
Bebidas Alcoólicas/microbiologia , Fermentação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Actinobacteria/metabolismo , Bacillus/genética , Bacillus/isolamento & purificação , Bacillus/metabolismo , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Bacteroidetes/metabolismo , Firmicutes/genética , Firmicutes/isolamento & purificação , Firmicutes/metabolismo , Aromatizantes , Humanos , Concentração de Íons de Hidrogênio , Lactobacillus/genética , Lactobacillus/isolamento & purificação , Lactobacillus/metabolismo , Methanomicrobiaceae/genética , Methanomicrobiaceae/isolamento & purificação , Methanomicrobiaceae/metabolismo , Methanomicrobiales/genética , Methanomicrobiales/isolamento & purificação , Methanomicrobiales/metabolismo , Methanosarcina/genética , Methanosarcina/isolamento & purificação , Methanosarcina/metabolismo , PaladarRESUMO
The confined modes of surface plasmon polaritons in boxing ring-shaped nanocavities have been investigated and imaged by using cathodoluminescence spectroscopy. The mode of the out-of-plane field components of surface plasmon polaritons dominates the experimental mode patterns, indicating that the electron beam locally excites the out-of-plane field component of surface plasmon polaritons. Quality factors can be directly acquired from the spectra induced by the ultrasmooth surface of the cavity and the high reflectivity of the silver (Ag) reflectors. Because of its three-dimensional confined characteristics and the omnidirectional reflectors, the nanocavity exhibits a small modal volume, small total volume, rich resonant modes, and flexibility in mode control.