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Spontaneous Fermentation (spontaneous + fermentation)
Selected AbstractsVolatile compounds after spontaneous fermentation of musts from Vitis vinifera cv. Albariño grapes cultivated in different origins from Rías Baixas AOC, SpainFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2006S. Zamúz Abstract White wines experimentally produced from the white grape variety Albariño from three different areas from Rias Baixas AOC, north-western Spain, have been analysed in this study. The contents of terpenes, C13 -norisoprenoids, alcohols, acetates and ethyl esters were determined by GC,MS. The Albariño wines from O Rosal are characterized by a high content of higher alcohols, while wines from Val do Salnés show the highest concentrations of free terpenes, acetates and ethyl esters; and wines of Condado do Tea show the highest concentrations of C13 -norisoprenids, principally due to the ,-ionone. Two principal components accounting for 90.7% of the total variance were calculated by means of a principal components analysis (PCA), and the graphical representation of these two components allows grouping the wines according their respective origins. Volatile compounds with fruity and floral odours showed the highest odour activity values, contributing in a great measure to the aroma of Albariño wines. Copyright © 2006 John Wiley & Sons, Ltd. [source] A comparison of the physicochemical, microbiological and aromatic composition of Traditional and Industrial Leben in TunisiaINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2010OLFA SAMET-BALI Traditional Tunisian Leben (TL) was produced according to the traditional method. Physicochemical and microbiological characteristics and major aromatic compounds were studied and compared to industrial Leben (IL) and experimental Leben (EL). The results show a decrease in lactose content and pH value and an increase in lactic acid during spontaneous fermentation. TL and EL were characterised by higher protein, lactose and ash contents but were less fatty and acidic than IL. Lactic acid bacteria (LAB) and yeasts present in TL were responsible for lactic acid fermentation and aroma development. The LAB and yeast counts in TL were higher than that in EL and IL. Dynamic headspace extraction procedure shows the existence of four major volatile compounds: acetaldehyde, ethanol, diacetyl and acetoin in TL, IL and EL. However, TL has the most important quantity of aroma. [source] Saccharomyces cerevisiae wine yeast populations in a cold region in Argentinean Patagonia.JOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2002A study at different fermentation scales Aims: To study the diversity and dynamics of indigenous Saccharomyces wine populations during Malbec spontaneous fermentation, a representative Patagonian red wine, at both industrial and laboratory scale. Methods and Results: Two molecular techniques, including restriction fragment length polymorphism of mitochondrial (mt) DNA and polymorphism of amplified , interspersed element sequences, were used for characterization of indigenous yeasts at strain level. The mtDNA restriction patterns showed the major discriminative power; however, by combining the two molecular approaches it was possible to distinguish a larger number of strains and, therefore, draw more representative conclusions about yeast diversity. Although a great diversity of wild Saccharomyces cerevisiae strains was observed, only nine represented more than half of the total Saccharomyces yeast biota analysed; five of these were common and took over the Malbec must fermentation in both vinifications. Conclusions: Many different indigenous S. cerevisiae strains were identified; nevertheless, the dominant strains in both industrial and laboratory vinification processes were just a few and the same. Significance and Impact of the Study: Small-scale fermentation appears to be a valuable tool in winemaking, one especially helpful in evaluating microbiological aspects of as well as possible interactions between inoculated selected strains and native strains. [source] Characterization of Biogenic Amines and Factors Influencing Their Formation in Traditional Chinese SausagesJOURNAL OF FOOD SCIENCE, Issue 6 2010Shiling Lu Abstract:, Biogenic amines in 42 traditional Chinese sausage samples obtained from different regions were determined by HPLC. The result showed that cadaverine was the major amine, followed by tyramine and putrescine. A total of 4 groups of samples were identified on the basis of total amines by cluster analysis. Group A included samples showing low amine contents (76.5 to 220 mg/kg) and accounted for 28.5% of the sausages examined. Group B included samples with moderate amine contents (220 to 600 mg/kg) and accounted for 45.2%. Group C included 11.9% of the samples showing high total biogenic amines contents (600 to 1000 mg/kg) and group D contained 14.28% of the samples showing very high levels of biogenic amines (higher than 1000 mg/kg). High correlation coefficients were found between the total counts of,Enterobacteria,and concentrations of total biogenic amines (r,= 0.73). Sanitary quality of raw materials and the specific flora are import factors influencing biogenic amines formation in traditional Chinese sausages. Practical Application: Biogenic amines are considered potentially harmful substances to human health worldwide and are usually found in fermented sausage.Traditional Chinese sausage is one form of spontaneously fermented sausage and manufactured in small-scale plants following spontaneous fermentation. Little information, however, exists on the traditional Chinese sausage. [source] Effect of Modified Enzymatic Catalysis on the Extraction of Diosgenin from Dioscorea zingiberensis C.,H.CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2007Wright Abstract Multi-enzymatic catalysis combined with acid hydrolysis is studied in order to enhance the efficiency of the enzymatic catalysis and reduce the mass transfer resistance from starch and cellulose in the extraction of diosgenin from Dioscorea zingiberensis C.,H. Wright. The cellulase is modified by polyethylene to increase its optimal reaction temperature and pH value. The modified cellulase shows better thermostability and resistance to alkali. The modified cellulase, , -amylase and , -glycosidase are used to construct the multi-enzyme and multi-enzyme catalysis is used as a pretreatment process. Compared to primary industrial techniques including acid hydrolysis, spontaneous fermentation and enzymatic catalysis, conventional techniques are optimized by using multi-enzymatic catalysis together with acid hydrolysis because of the higher reaction efficiency and lower levels of manipulation required. The purity of the product is more than 96,% with this technique, and the melting point is 205,207,°C. The diosgenin yield rate and the extraction rate reached are 2.43,% and 98,%, respectively. IR and 1H NMR spectroscopy were used to confirm the structure of the product. [source] | ||||||||||