Ultrasound-assisted extraction of hemicelluloses from grape pomace using response surface methodology.

An ultrasound-assisted procedure was applied to the extraction of hemicelluloses from grape pomace at a mild temperature (20°C). A Central composite design (CCD) was employed to optimize the ultrasound-assisted extraction (UAE) of hemicelluloses from grape pomace with the aim to maximize their extraction yield, and, also, the obtention of the main polymers forming this fraction: Xyloglucans (XLG), Mannans (MAN) and Xylans (XN). Extraction time (X1), solid:liquid ratio (X2) and KOH concentration (X3) were the variables used to optimize the process. The conditions that maximize (1) the extraction yield of hemicelluloses and the contents of (2) XLG, (3) MAN and (4) XN, were: (1) X1=2.6h; X2=1:48 (w/v); X3=0.4M, (2) X1=2.9h; X2=1:57 (w/v); X3=2.25M, (3) X1=2.7h; X2=1:58(w/v);X3=2.2M, and (4) X1=3h; X2=1:60 (w/v); X3=2.3M, respectively. Under these conditions, the maximum extraction yield of hemicelluloses, XLG, MAN and XN contents were: ∼7.9±0.2%, ∼3.6±0.02%, ∼1.1±0.04% and ∼1.2±0.02%, respectively. Close agreement between experimental and predicted values was found. The results suggest that the ultrasound-assisted extraction could be a good option for the extraction of hemicellulosic polysaccharides from grape pomace at industrial level.

Effect of power ultrasound application on aqueous extraction of phenolic compounds and antioxidant capacity from grape pomace (Vitis vinifera L.): experimental kinetics and modeling.

The kinetics of both conventional (mechanical stirring, 200rpm) and acoustic (55±5kHz, 435±5W/L) aqueous extraction of total phenolic content and antioxidant capacity from grape pomace by-products (Vitis vinifera L.) have been experimentally evaluated and modeled at different extraction temperatures (20, 35 and 50°C). A gradual and significant increase of total phenolic content and antioxidant capacity of the extracts was observed as the temperature increased, the highest values being obtained in the case of the extraction assisted acoustically. According to the results, the acoustic assistance of the extraction process led to aqueous extracts with phenolic and antioxidant characteristics similar to those obtained with mechanical stirring, working under lower temperature conditions and during less operating time. Specifically, the conventional extraction of total phenolics at 35 and 50°C did not differ significantly from extractions assisted with power ultrasound at 20 and 35°C, respectively; and the acoustic process required approximately 3, 4 and 8 times less time, at 20, 35 and 50°C, than the conventional extraction to obtain extracts with similar characteristics. The extraction curves obtained for total phenolic content and antioxidant capacity, measured by the ABTS and FRAP methods, were properly represented by a modified Weibull model for both conventional and acoustic extractions within the temperature range 20-50°C, presenting an average percentage of explained variance⩾97.9%, and an average mean relative error⩽7.0%. A high correlation (r(2)⩾0.992) was observed between the experimental and simulated values for all the quality attributes in study.

Ultrasound-assisted extraction of pectins from grape pomace using citric acid: a response surface methodology approach.

An ultrasound-assisted procedure for the extraction of pectins from grape pomace with citric acid as the extracting agent was established. A Box-Behnken design (BBD) was employed to optimize the extraction temperature (X1: 35-75°C), extraction time (X2: 20-60 min) and pH (X3: 1.0-2.0) to obtain a high yield of pectins with high average molecular weight (MW) and degree of esterification (DE) from grape pomace. Analysis of variance showed that the contribution of a quadratic model was significant for the pectin extraction yield and for pectin MW whereas the DE of pectins was more influenced by a linear model. An optimization study using response surface methodology was performed and 3D response surfaces were plotted from the mathematical model. According to the RSM model, the highest pectin yield (∼32.3%) can be achieved when the UAE process is carried out at 75°C for 60 min using a citric acid solution of pH 2.0. These pectic polysaccharides, composed mainly by galacturonic acid units (<97% of total sugars), have an average MW of 163.9 kDa and a DE of 55.2%. Close agreement between experimental and predicted values was found. These results suggest that ultrasound-assisted extraction could be a good option for the extraction of functional pectins with citric acid from grape pomace at industrial level.

Accuracy of sentinel lymph node biopsy after neo-adjuvant chemotherapy in patients with locally advanced breast cancer and clinically positive axillary nodes.

BACKGROUND: Feasibility and accuracy of sentinel node biopsy (SLNB) after the delivery of neo-adjuvant chemotherapy (NAC) is controversial. We here report our experience in NAC-treated patients with locally advanced breast cancer and clinically positive axillary nodes, and compare it with the results from our previous randomized trial assessing SLNB in early-stage breast cancer patients. PATIENTS AND METHODS: Sixty-four consecutive patients with large infiltrating tumor and clinically positive axillary nodes received NAC and subsequent lymphatic mapping, SLNB and complete axillary lymph node dissection (ALND). The status of the sentinel lymph node (SLN) was compared to that of the axilla. RESULTS: At least one SLN was identified in 60 of the 64 patients (93.8%). Among those 60 patients, 37 (61.7%) had one or more positive SLN(s) and 23 (38.3%) did not. Two of the patients with negative SLN(s) presented metastases in other non-sentinel nodes. SLNB thus had a false-negative rate, a negative predictive value and an overall accuracy of 5.1%, 91.3% and 96.7%, respectively. All these values were similar to those we reported for SLNB in the settings of early-stage breast cancer. CONCLUSION: SLNB after NAC is safe and feasible in patients with locally advanced breast cancer and clinically positive nodes, and accurately predicts the status of the axilla.

Tumor fibroso solitario doble gigante de localización mesocólica. Extirpación radical / Solitary fiborus tumour double with mesocolon localization. Radical extirpation

El hemangiopericitoma descrito inicialmente como un distintivo de neoplasia de tejidos blandos, posiblemente de origen peritocítico y que durante años parecía que este patrón de crecimiento no era específico por englobar lesiones no relacionadas (benignas y malignas) y siendo dicha lesión considerada más como diagnóstico de exclusión. Dentro del heterogéneo grupo de neoplasias HPC-like, tres clases de lesiones podrían ser individualizadas. La primera corresponde a los que ocasionalmente presentan características HPC-like (sarcoma sinovial). Los de 2ª clase muestran evidencia clara de mioide/pericítica y corresponden a los verdaderos PCS, con clínica benigna por lo general (glomangiopericitoma /miopericitoma, miofibromatosis infantil y un subgrupo sinosales HPCs). La 3ª es el grupo lesional del tumor solitario (fibroso o celular). La definición de hemangiopericitoma se va dejando pues como categoría vacía. Presentamos un caso de Tumor Fibroso Solitario tipo celular de localización mesocólica, doble y separados por 1-2 cm de mesocolon y que fue posible erradicarlo quirúrgicamente en su totalidad. Tumor vascular y potencialmente maligno, de muy escasa presencia mesentérica pura. Anteriormente denominado hemangiopericitoma siendo en la actualidad considerado como tumor fibroso solitario de tipo fibroso o celular. Destacamos el tamaño de ambas tumoraciones mesocólicas, hasta ahora no descritas y que desde el punto de vista histológico pueden considerarse como no agresivas (AU)

The hemangiopericitoma (HPC) was initially described as a soft tissue tumour that probably came from the peritocitic cells. For many years the growing pattern involved benign and malignant lesions, and their diagnosis were made based on exclusion criteria. In this heterogeneous group of tumours, three types can be described. The first one corresponds to those tumours that occasionally present HPC-like characteristics (sinovial sarcoma). The second class clearly show the characteristics of peritocitic/miode cells. They are the true HPC tumours and they usually are benign (glomangiopericitoma/miopericitoma, paediatric miofibromatosis, and a subgroup of sinosal HPC). And the third class involves the solitary tumour (fibrous or cellular). So the definition of HPC is left as an empty category. We present a case of a cellular type solitary fibrous tumour with a double localization at mesocolon, separated by 1-2 centimeters, that was completely surgically removed. It was a vascular tumour, potentially malignant and with a very low pure mesenteric component. It was previously called HPC (benign or malignant), but it is actually considered as a solitary fibrous tumour. We would like to emphazise the size of both mesocolic tumours, that have not been previously described, and thatfrom an histological point of view they can be considered as non aggressive (AU)

Effects of supercritical carbon dioxide (SC-CO(2)) oil extraction on the cell wall composition of almond fruits.

Extraction of oil from almond fruits using supercritical carbon dioxide (SC-CO(2)) was carried out at 50 degrees C and 330 bar on three sets of almonds: raw almond seeds, raw almond kernels, and toasted almond seeds. Three different oil extraction percentages were applied on each set ranging from approximately 15 to 16%, from approximately 27 to 33%, and from approximately 49 to 64%. Although no major changes were detected in the fatty acid composition between fresh and partially defatted samples, carbohydrate analysis of partially defatted materials revealed important changes in cell wall polysaccharides from almond tissues. Thus, at low extraction percentages (up to approximately 33%), pectic polysaccharides and hemicellulosic xyloglucans were the main type of polymers affected, suggesting the modification of the cell wall matrix, although without breakage of the walls. Then, as supercritical fluid extraction (SCFE) continues and higher extraction rates are achieved (up to approximately 64%), a major disruption of the cell wall occurred as indicated by the losses of all major types of cell wall polysaccharides, including cellulose. These results suggest that, under the conditions used for oil extraction using SC-CO(2), fatty acid chains are able to exit the cells through nonbroken walls; the modification of the pectin-hemicellulose network might have increased the porosity of the wall. However, as high pressure is being applied, there is a progressive breakage of the cell walls allowing the free transfer of the fatty acid chains from inside the cells. These findings might contribute to providing the basis for the optimization of SCFE procedures based on plant food sources.

Composition assessment of raw meat mixtures using ultrasonics.

The use of ultrasonic velocity measurements to determine the composition of dry fermented sausages was assessed. Mixtures of ground lean and fatty tissues were prepared to cover a wide range of fat (2-90 wt.%), moisture (7-76 wt.%), and protein (2-21 wt.%) contents. The ultrasonic velocity in fat decreased on average 5.6 ms(-1) per °C increase in temperature, due to the negative temperature coefficient for fat and the fat melting, which is observed in (DSC) differential scanning calorimetry analysis. The ultrasonic velocity temperature dependence allowed the determining of the fat, moisture and protein+others content, by measuring the ultrasonic velocity in the mixtures at 4 and 25°C and using a semi-empirical equation. The explained variance was 99.6% for fat, 98.7% for moisture and 85.4% for protein+others. The results obtained show the feasibility of using ultrasonic velocity measurement to assess the composition of meat products such as dry fermented sausages, rapidly and non-destructively.

Effects of Drying Pretreatments on the Cell Wall Composition of Grape Tissues.

Pretreatments by consecutive dipping in NaOH, citric acid, and K(2)S(2)O(5) solutions help to increase the drying rate of grapes and to reduce the darkening due to enzymic and nonenzymic browning during storage of raisins. However, such pretreatments have also an important effect on the cell wall composition of grape tissues. In both skin and pulp tissues the yield of cell wall material decreased substantially with processing, by 19.7 and 22.5%, respectively. Sodium hydroxide and citric acid solutions solubilized large amounts of pectic substances and xyloglucans, whereas potassium metabisulfite solution caused minor modifications to the composition of cell wall polysaccharides. Moreover, drying pretreatments promoted important changes in the amounts of Ca and Mg associated with cell wall components, which suggested possible structural rearrangements of polymers within the wall. All of these observations were in good agreement with the main results obtained after the application of a nondegradative technique such as FTIR spectroscopy to the cell wall preparations of fresh and processed tissues.

Thin-layer chromatographic determination of catecholamines in rat plasma.

A TLC method for the quantitative determination of epinephrine, norepinephrine and dopamine in rat plasma is described. After deprotenization, catecholamines were adsorbed on acid-alumina and acetylated. The acetyl derivatives were extracted using a C18 minicolumn, resolved on HPTLC plates and quantitated by fluorescence densitometry at 415 nm, using isoprenaline as internal standard.

Simultaneous determination of vanillylmandelic, homovanillic and 5-hydroxyindoleacetic acids in human urine by thin layer chromatography.

A TLC method for the simultaneous analysis of vanillylmandelic, homovanillic and 5-hydroxyindole-3-acetic acids in urine is described. The sample is cleaned up through a cyano minicolumn and extracted with diethyl ether. The acids are resolved by high-performance TLC, visualized by Folin Ciocalteau reagent and quantificated by densitometry at 600 nm with beta-(4-hydroxy-3-phenyl) acetic acid as the internal standard.

A simple thin-layer chromatographic method for the analysis of buprenorphine in urine.

A simple and sensitive (at the ng/mL level) method for buprenorphine assay in urine is described. Buprenorphine is extracted by a C18 cartridge, derivatized with dansyl chloride, resolved by a uni-dimensional, two developing mobile phase high-performance thin layer chromatography system and quantified by fluorescence densitometry at 340 nm.

Microbial and chemical changes in 'Sobrasada' during ripening.

'Sobrasada' is a raw-cured product typical of Mallorca (Balearic Islands). Throughout its ripening process the product, like other raw-cured sausages, undergoes a series of chemical and microbial changes which lead to the formation of its desirable final characteristics. In the 'sobrasada' studied, the breeds, feeding and casings used in the Balearic Islands were employed. The evolution of different groups of microorganisms was followed: mesophylic aerobic microorganisms, lactic acid bacteria, Enterobacteriaceae, yeasts and moulds, group D Streptococcus, proteolytic microorganisms and lipolytic microorganisms. It was found that the predominant flora, from the beginning to the end, was made up of lactic acid bacteria. Conversely, Enterobacteriaceae disappeared as ripening went on, and the rest of the microbial groups studied underwent little variation along the process. An important characteristics of the product is the fast fall of pH, from values near 6·0 to values around 5·3, in the first week.