RESUMEN
Sterilization and clarification are essential to produce wine of high quality and stability, microfiltration is a serious candidate for both purposes. In this work, microfiltration of fermented mulberry wine was evaluated for the first time. Four different commercial membranes, of two different materials (PES, PVDF) and two different nominal pore sizes (0.22 µm and 0.45 µm) were employed. Pore blocking model was used to identify the fouling mechanism, foulant constituents were revealed by FT-IR spectra. The effect of microfiltration on permeate quality of mulberry wine was also involved. The results indicated that cake formation was the dominant mechanism during steady-state of mulberry wine microfiltration, independently on the membrane property. The fouling layer was mainly composed of protein and polysaccharides, which induced basically reversible overall filtration resistance. Microfiltration delivered a superior clarity, highly polydisperse and light-color mulberry wine with a satisfactory sterilization stability. It preserved the main basic properties and organic acid contents of mulberry wine while resulted in certain loss of volatile compounds, especially esters and alcohols. This work has provided a scientific reference for producing mulberry wine, a modern functional beverage.
RESUMEN
A novel intestinal-targeted carrier for pH-responsive protection of lactic acid bacteria in stomach and rapid release of lactic acid bacteria in small intestine is successfully developed. The proposed carrier is composed of a Ca-alginate/protamine (CAP) composite shell and a Lactobacillus-casei-encapsulated Ca-alginate (CA) core. The carriers are prepared simply by a coextrusion minifluidic and subsequent adsorption method. The CAP composite shell offers not only improved protection for Lactobacillus casei to guarantee the endurance and survival in the stomach but also satisfactory intestinal-targeted characteristics to guarantee the rapid release of Lactobacillus casei in the small intestine. In the stomach, where there is an acidic environment, the diffusion channels delineated by the CA networks in the CAP composite shell of the carriers are choked with protamine molecules; as a result, it is hard for the gastric acid to diffuse across the CAP composite shell and thus the encapsulated Lactobacillus casei inside carriers can be efficiently protected. However, when they come to the small intestine, where there is a neutral environment, the carriers dissolve rapidly because of the cooperation between protamine and trypsin; consequently, the encapsulated Lactobacillus casei can be quickly released. The proposed CAP composite carrier provides a novel mode for developing efficient protection systems, responsive controlled-release systems, and intestinal-targeted drug delivery systems.
Asunto(s)
Alginatos/química , Calcio/química , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Intestinos/microbiología , Lacticaseibacillus casei/química , Probióticos/química , Animales , Portadores de Fármacos/metabolismo , Sistemas de Liberación de Medicamentos/instrumentación , Ácido Glucurónico/química , Ácidos Hexurónicos/química , Concentración de Iones de Hidrógeno , Ácido Láctico/metabolismo , Lacticaseibacillus casei/metabolismo , Ratones , Probióticos/administración & dosificaciónRESUMEN
The aim of this study was to investigate and compare the microbial community structures of eubacteria and archaea in the pit mud of Chinese Luzhou-flavor liquor from the wall (C(w)) and bottom (C(b)) of cellar through nested PCR-denaturing gradient gel electrophoresis (DGGE). The Shannon-Wiener index (H) calculated from the DGGE profiles showed that the community diversities of eubacteria and archaea in samples from C(b) were almost higher than that from C(w). In addition, cluster analysis of the DGGE profiles revealed that some differences were found in the microbial community structure in samples from different locations. The closely relative microorganisms of all eubacterial 16S rRNA gene sequences fell into four phyla (Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria), including 12 genera and 2 uncultured eubacteria. Moreover, 37.1% eubacteria were affiliated with Clostridium. Particularly, genus Acinetobacter was absent in all samples from C(b) but present in all samples from C(w). The closely relative microorganisms of all archaeal 16S rRNA gene sequences fell into four genera, which included Methanobrevibacter, Methanoculleus, Methanobacterium and Methanosaeta, while the dominant archaea in samples from C(w) and C(b) were similar. Results presented in this study provide further understanding of the spatial differences in microbial community structure in the pit mud, and is of great importance for the production and quality improvement of Luzhou-flavor liquor.