Alexandre Schuler

Yeast species involved in artisanal cachaça fermentation in three stills with different technological levels in Pernambuco, Brazil

Both the taste and aroma of cachaça, an alcoholic beverage produced by yeast fermentation of sugar cane, are influenced by yeast metabolites and volatiles. The knowledge of yeast population dynamics during the fermentation process will help to establish the basis for quality control of alcoholic beverage. In the present work, the population dynamics of three fermentation processes, with differing levels of technological sophistication, were studied. Saccharomyces cerevisiae was found to be the dominant species, but Candida milleri (Candida humilis), Pichia caribbica, Pichia guilliermondii and Zygosaccharomyces fermentati (Lachancea fermentati) were also significantly involved. In addition, four new yeast species that are not represented in NCBI/EMBL nucleotide database were found. These yeasts were classified as Candida sp., Candida drosophilae-like, Candida ubatubensis-like and Zygosaccharomyces sp. In fermentation trails at laboratory scale, all species were found to contribute to the production of volatiles. Thus it is probable that product quality is strongly dependent on population dynamics during the fermentation process.

Influência do manejo do rebanho, das condições higiênicas da ordenha e da fase de lactação na composição química do leite de cabras Saanen

The objective of this trial was to evaluate the effect of lactation stage in the chemical and physical characteristics of milk from Saanen goats as well as to investigate the effects of flock management, milking sanitary conditions, and lactation phase in the milk fatty acid profile. Twenty goats were randomly assigned to four groups of five animals each. Flock management differed by the presence or absence of males in the groups while milking sanitary conditions differed either by a poor or by a good milking hygiene. Milk samples were collected at 35, 85 and 135 days of lactation. Results showed that milk yield was as expected at 135 days of lactation; peak milk production was observed at 35 days of lactation and decreased linearly as lactation progressed. Milk yield, milk fat content, and milk acidity all changed according to the lactation stage. Milking sanitary conditions and flock management did not affect the milk fatty acids profile. However, milk fatty acids profile differed at different lactation stages with the greatest content of saturated fatty acids at 85 days of lactation.

Static Magnetic Fields Enhancement of Saccharomyces cerevisae Ethanolic Fermentation

Magnetic effects induced in ethanolic fermentation by Saccharomyces cerevisiae strain DAUFPE‐1012 were studied during a 24 h exposure to 220 mT steady magnetic fields (SMF) at 23 ± 1 °C, produced by NdFeB rod magnets. The magnets were attached diametrically opposed (N to S) to a cylindrical tube reactor. The biomass growth in the reactor culture media (yeast extract + glucose 2%) during 24 h was monitored by measurements of optical density, which was correlated to cell dry weight. Ethanol concentration and glucose level were measured every 2 h. The pH of the culture media was maintained between 4 and 5. As a result, biomass (g/L) increased 2.5‐fold and ethanol concentration 3.4‐fold in magnetized cultures ( n = 8) as compared with SMF nonexposed cultures ( n = 8). Glucose consumption was higher in magnetized cultures, which correlated to the ethanol yield.

Influence of nitrogen supply on the production of higher alcohols/esters and expression of flavour-related genes in cachaça fermentation.

This study provides the first attempt to analyse the influence of ammonium supplements on sugar-cane juice fermentation and the flavour profile in a cachaça industrial process. The objective was to find a relationship between higher alcohol/ester content and the transcription levels of the main genes involved in production of these compounds under cachaça fermentation. Sugar-cane juice with a low amount of assimilable nitrogen (81 mg N/L), was further supplemented with mid-range or high concentrations of ammonium sulfate. Overall, higher alcohol production was reduced by ammonium supplementation, and this can be correlated with a general downregulation of genes encoding decarboxylases and dehydrogenases of the Ehrlich pathway. The production of acetate esters was enhanced by mid-range ammonium supplementation and the production of acyl esters by high ammonium supplementation. The acyl esters could be correlated with expression of alcohol acyl-transferase EEB1 and the acyl esterase IAH1.

Influence of static magnetic fields on S. cerevisae biomass growth

Biomass growth of Saccharomyces cerevisiae DAUFPE-1012 was studied in eight batch fermentations exposed to steady magnetic fields (SMF) running at 23oC (± 1oC), for 24 h in a double cylindrical tube reactor with synchronic agitation. For every batch, one tube was exposed to 220mT flow intensity SMF, produced by NdFeB rod magnets attached diametrically opposed (N to S) magnets on one tube. In the other tube, without magnets, the fermentation occurred in the same conditions. The biomass growth in culture (yeast extract + glucose 2%) was monitored by spectrometry to obtain the absorbance and later, the corresponding cell dry weight. The culture glucose concentration was monitored every two hours so as the pH, which was maintained between 4 and 5. As a result, the biomass (g/L) increment was 2.5 times greater in magnetized cultures (n=8) as compared with SMF non-exposed cultures (n=8). The differential (SMF-control) biomass growth rate (135%) was slightly higher than the glucose consumption rate (130 %) leading to increased biomass production of the magnetized cells.

Profile of milk fatty acids from moxotó goats fed with different levels of manicoba (Manihot Glaziovii Muel Arg.) silage

The objective of this work was to evaluate the effects of the manicoba silage use (Manihot glaziovii Muel Arg.) in different roughage:concentrate ratios (30:70; 40:60; 50:50 and 60:40 %) on the fatty acids profile of the milk from Moxoto goats. Eight multiparous goats with approximately 60 post-birth days and weigh 44 kg on average were used in a Double Latin Square with four treatments, four periods and four animals. Each period lasted 15 days with 10 days of adaptation to experimental diets and 5 days of milk collection. The results of the fatty acids analyses were submitted to the analysis of variance (ANOVA) and regression. An increasing linear effect for the miristic acid (C14:0) and decreasing for the linoleic acid (C18:3) was observed in function of the silage levels in diet. The milk fat presented high contents of desirable fatty acids (C18:0 + unsaturated acids), considered as nutritionally important due to their benefits to the human health. It could be concluded that the manicoba silage could be included in the diet with the participation of up to 60%, presenting a nutrient supply of high nutritional value.

Preliminary Phytochemical Profile and Characterization of the Extract from the Fruits of Xylopia frutescens Aubl. (Annonaceae)

Abstract The chemical composition of essential oils extracted from Xylopia frutescens Aubl. (Annonaceae) fruit (collected in Pernambuco, Brazil) was examined by TLC and GC/MS. TLC analysis detected compounds from the flavonoid and terpenoid groups. GC/MS detected 23 terpenoid compounds, in which the principal components were germacrene D (24.2%), linalool (12.1%), β-pinene (8.0%), cis-sabinene hydrate (7.9%), trans-pinocarveol (7.8%), α-copaene (7.0%) and limonene (5.6%). Other constituents found were sabinene, m-cymene, 1,8-cineole, β-ocimene, perillene, cis-sabinol, α-campholenal, isopinocamphone, terpinen-4-ol, verbenone, trans-carveol, carvone, perillyl alcohol, α-cubebene, β-cadinene and elemol. Most of these compounds have not been detected in fruit extracts of X frutescens before; therefore this study represents the most comprehensive analysis to date of the chemical components in the fruits of this plant.