Transfer kinetics of labeled aroma compounds from liquid media into coffee beans during simulated wet processing conditions.

The transfer kinetics of three labelled compounds (butanal, 2-phenyethanol, isoamyl acetate) was studied from a liquid medium into the coffee beans during simulated wet processing using four media (M) (M1: contained dehulled beans, M2: contained demucilaginated beans, M3: contained depulped beans, M4: contained depulped beans with yeast). Trials were carried out at 25 °C, under agitation and for five time periods (0, 6, 12, 24 and 48 h), and then the labelled volatiles were analyzed by SPME-GC-MS. The three labelled molecules were transferred into the coffee beans with different mass transfer rates; reaching at 12hrs in the M4, 0.2 ± 0.03, 11.2 ± 0.66 and 1.3 ± 0.04 µg/g of coffee respectively for butanal, 2-phenyethanol and isoamyl acetate. The parchment resistance significantly affected the mass transfer of the 2-phenylethanol. Butanal and isoamyl acetate underwent metabolic reactions, which decreased their amount in the coffee beans. Furthermore, an interaction between molecules and the yeast was observed and decreased significantly the butanal's transfer.

Impact of blanching, sweating and drying operations on pungency, aroma and color of Piper borbonense.

Low pungency, high aromatic potential and red color, give to Piper borbonense its originality when compared to Piper nigrum. Effects of blanching, sweating and drying on these characteristics were assessed. The three operations had no impact on the concentration of piperine and essential oil but affected the composition of essential oil slightly and considerably affected the color of the pepper. The "wet process", including blanching, sweating and drying, had the largest impact on the composition of aroma, increasing para-cymene content by 89% and reducing safrole content by 33% in dried pepper compared to fresh. Blanching increased the drying rate thus reducing drying time. Drying had a major impact on color, which changed from red to brown. The biggest differences observed led to reductions of 2.2, 7.9 and 8.4units in L∗, a∗ and b∗ values, when chromatic values measured in fresh pepper were compared to those of dried pepper.

Impact of fermentation on nitrogenous compounds of cocoa beans (Theobroma cacao L.) from various origins.

Tangential filtration technique was used to separate and quantify three different fractions of nitrogenous compounds depending on their molecular size, during cocoa fermentation. On every phenotype and origin analyzed, protein profile of non-fermented samples was similar. During fermentation course, proteins get degraded with a concomitant increase in amino acids content. Peptides between 3 and 10 kDa were observed at low levels. A strong correlation between amino acids and ammonia nitrogen, a fermentation marker was found. Attention was drawn on each fraction, and enabled to point out other phenomenon occurring during fermentation. The migration of some nitrogenous compounds towards the bean shell during fermentation was demonstrated. Acetone treatment of cocoa powder prior to SDS-PAGE led to losses of nitrogenous compounds. This result gives clues on the tanning phenomenon carried out by polyphenols on nitrogenous compounds, phenomenon which increases during fermentation.

Near infrared spectroscopy as a new tool to determine cocoa fermentation levels through ammonia nitrogen quantification.

Fermentation is a key step in obtaining fine cocoa through the formation of potent aroma precursors. The fermentation level of cocoa beans is traditionally assessed by measuring the amount of ammonia nitrogen (NH3) using the time-consuming Conway technique. Near infrared spectroscopy (NIRS), a rapid and efficient tool, was used to analyze NH3 levels in several hundred cocoa samples at different fermentation levels from six geographical origins. Fermentation levels were expressed as the number of fermentation days and sum of temperatures. The correlation between Conway results and NIRS spectra enabled the development of a reliable and accurate NIRS calibration to determine NH3 content. We confirm that NH3 is produced during fermentation and its amount depends on the fermentation time, sum of temperatures and geographical origin. NIRS could be used by chocolate manufacturers as a routine method to sort cocoa samples according to their level of fermentation.

Climatic factors directly impact the volatile organic compound fingerprint in green Arabica coffee bean as well as coffee beverage quality.

Coffee grown at high elevations fetches a better price than that grown in lowland regions. This study was aimed at determining whether climatic conditions during bean development affected sensory perception of the coffee beverage and combinations of volatile compounds in green coffee. Green coffee samples from 16 plots representative of the broad range of climatic variations in Réunion Island were compared by sensory analysis. Volatiles were extracted by solid phase micro-extraction and the volatile compounds were analysed by GC-MS. The results revealed that, among the climatic factors, the mean air temperature during seed development greatly influenced the sensory profile. Positive quality attributes such as acidity, fruity character and flavour quality were correlated and typical of coffees produced at cool climates. Two volatile compounds (ethanal and acetone) were identified as indicators of these cool temperatures. Among detected volatiles, most of the alcohols, aldehydes, hydrocarbons and ketones appeared to be positively linked to elevated temperatures and high solar radiation, while the sensory profiles displayed major defects (i.e. green, earthy flavour). Two alcohols (butan-1,3-diol and butan-2,3-diol) were closely correlated with a reduction in aromatic quality, acidity and an increase in earthy and green flavours. We assumed that high temperatures induce accumulation of these compounds in green coffee, and would be detected as off-flavours, even after roasting. Climate change, which generally involves a substantial increase in average temperatures in mountainous tropical regions, could be expected to have a negative impact on coffee quality.

Effect of mycorrhization on the accumulation of rishitin and solavetivone in potato plantlets challenged with Rhizoctonia solani.

The effect of colonization with the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum on the content of rishitin and solavetivone was determined in potato plants cv. Goldrush challenged with Rhizoctonia solani. Mycorrhization stimulated significantly the accumulation of both phytoalexins in roots of plantlets challenged with R. solani but did not influence phytoalexin levels in non-challenged plantlet roots. No accumulation of solavetivone or rishitin was detected in shoots. In Petri dish bioassays, rishitin and solavetivone inhibited mycelial growth of R. solani.

Examination of the contaminants and performance of animals fed and bedded using de-inking paper sludge.

In the noncereal-producing areas, there is not enough straw to supply the amount required for animal bedding. However, pulp and paper mills produce tons of wood fiber wastes, including de-inking paper sludge (DPS), in which most toxic compounds are at their detection limit. Among the detected compounds in DPS, aluminum, copper, and polycyclic aromatic hydrocarbons (PAHs) are present and were selected as model molecules. In this context, broilers were submitted to a diet containing 0, 5, and 10% of their ration as DPS. In addition, broilers and pigs were grown on de-inking paper sludge and wood shavings beddings. The presence of aluminum and copper were evaluated in blood and bones, whereas the presence of PAHs was evaluated in fat, liver, meat, and urine or blood of broilers and pigs. Animal performances were also investigated. DPS bedding did not increase aluminum or copper contents of blood or bones or PAHs in animal tissues. Animal performances and health were similar on DPS and wood shaving beddings. Using DPS as bedding material provides an integrated source of disposal of DPS and animal manure.

Changes of volatile compounds during heating of bacuri pulp.

The formation of volatile compounds from precursors or through chemical rearrangement during heat treatment of bacuri pulp at fruit natural pH were studied using simultaneous distillation/extraction (SDE) technique. An increase of the quantities of oxygenated and hydrocarbon terpenes and, to a lesser degree, aldehydes, was observed after SDE at pH 3, relative to the other extraction methods used, SDE at neutral pH and solid phase extraction (SPE). More particularly, linalool, linalool furanoxides, alpha-terpineol, hotrienol, nerol oxide, nerol, and geraniol were isolated in more important quantities after the first treatment than after the others. These results can be partially explained by the hydrolysis of glycosidically bound compounds previously identified in bacuri. Other pathways such as polyol rearrangements were also involved. The formation of linalool and alpha-terpineol was probably the result of the rearrangement of 2,6-dimethyloct-1-ene-3,7-diol. Moreover, it was assumed that oxidation reactions occurred during SDE at pH 3; more particularly, linalool pyranoxides partially resulted from nonenzymatic oxidation of linalool. When SDE was performed at pH 3, an increase of furfural and 4-methoxy-2,5-dimethyl-3(2H)-furanone was noticed. The modifications of the concentration of aliphatic aldehydes, known as lipid oxidation compounds, and of fatty acid esters were in good agreement with the observed decrease of palmitic and linoleic acid concentrations during this treatment. Moreover, important amounts of 2-acetyl-1-pyrroline were found in the SDE extract recovered at pH 7.

Frequency of infections in cirrhotic patients presenting with acute gastrointestinal haemorrhage.

The frequency of infection at the time of admission with upper gastrointestinal haemorrhage has been determined in 149 successive cirrhotic patients admitted to an intensive care unit. Infection status was investigated by clinical examination, chest X-ray, and blood, urine and ascitic fluid culture. At initial examination infection was present in 32 patients (22 per cent) and was often in the form of septicaemia or spontaneous peritonitis; the bacteria responsible were frequently digestive in origin. At endoscopy, acute lesions of gastroduodenal mucosa were more frequent among infected patients, whereas gastro-oesophageal varices and chronic gastroduodenal ulcers were more frequent among the non-infected patients. Acute mucosal lesions were observed in 70 per cent of infected patients and in 19 per cent of non-infected patients. The mortality rate was higher in infected patients. Infection and the frequency of acute mucosal lesions were related to the severity of the cirrhosis. It is suggested that these lesions could be due to stress secondary to infection.

Induction of antituberculous immunity by polysaccharidic contaminants of crude ribosomal vaccines isolated from Mycobacterium bovis, strain BCG.

Crude ribosomal fractions isolated from the BCG strain of Mycobacterium bovis are capable of inducing antituberculous immunity in CF-1 mice. These crude preparations contain varying amounts of polysaccharides in addition to ribosomal ribonucleic acid and proteins. Whereas these latter two constituents of the crude fractions were found inactive, high levels of antituberculous immunity were induced by a ribosomal sub-fraction significantly enriched with polysaccharides. These results strongly suggest that polysaccharides play an important role in the induction of antituberculous immunity in CF-1 mice immunized with crude ribosomal fractions isolated from the BCG strain and that if ribosomal proteins and/or RNA are of a certain importance, their role would be secondary (complexes providing physical support to polysaccharides, adjuvant, etc.).

Factors affecting the immunizing activity of ribosomal fractions isolated from Mycobacterium tuberculosis var. bovis strain BCG.

Levels of antituberculous immunity similar to those induced by live BCG vaccine were detected in CF1 mice immunized with ribosomal fractions isolated from Mycobacterium tuberculosis var. bovis, strain BCG, and challenged 3 weeks later with the virulent H37Rv strain of Mycobacterium tuberculosis var. hominis. The activity of the crude ribosomal preparations was found to be a function of the immunizing doses and the immunity induced by 1.0-mg doses remained at the same high level after 4 weeks of storage at 4 degrees C but decreased markedly thereafter. Dialysis and lyophilization had no detrimental effects on the activity of the crude preparations whereas purification by column chromatography on Sephadex G-200 annihilated their biological activity. Crude low-polysaccharide-containing preparations were found inactive even at the 1.0-mg dose level and results of experiments performed with crude ribosomal fractions of varying polysaccharide contents strongly suggest that polysaccharides, or RNA-polysaccharide complexes, may play an important role in the induction of immunity with crude ribosomal fractions isolated from the BCG strain of Mycobacterium tuberculosis var. bovis.

Preservation of mycobacterial suspensions at -55 degrees C.

Suspensions in dilute Sauton's medium of 14 mycobacterial strains grown under identical conditions were prepared with bacilli harvested at their midlog phase of growth,and were frozen and stored at -55 degrees C. Survivals, estimated by CFU determinations after periodic intervals of storage, showed no adverse effect of freezing and thawing on any of the strains. Effectiveness of preservation, however, varied from strain to strain and no correlation existed between effectiveness and species of mycobacteria. No noticeable changes in the virulence of the H37Rv strain and in the immunizing activity of BCG were detected after prolonged storeage. Results of experimentsperformed with two strains suspended in seven diluents suggest that some are more suitable for long-term preservation, particularly so for the more sensitive one.