The cell wall materials (CWMs) from sweetpotato (Ipomoea batatas cv. Kokei 14), cassava (Manihot esculenta), and potato (Solanum tuberosum cv. Danshaku) and commercial sweetpotato fiber as well as their polysaccharide fractions were analyzed for sugar composition by the high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) method. The separation of arabinose and rhamnose, and xylose and mannose, by this method has been improved using a CarboPac PA 10 column. Pretreatment of the CWMs and cellulose fractions with 12 M H(2)SO(4) was required for complete hydrolysis to occur. Commercial sweetpotato fiber was found to be mainly composed of glucose (88.4%), but small amounts of other sugars were also detected. Among the root crops, sweetpotato CWM had the highest amount of pectin and galacturonic acid. Fucose was detected only in cassava CWM and its hemicellulose fraction, while galactose was present in the highest amount in potato CWM. Among the polysaccharide fractions, it was only in the hemicellulose fraction where significant differences in the sugar composition, especially in the galactose content, were observed among the root crops.

Honey is one of the oldest sweetening foods and has economic importance, making this product attractive to adulteration with cheap sugars. This can cause a critical problem in the honey industry and a possible health risk. The present work has the aim of evaluating the authenticity of honey commercialized in two different provinces of Ecuador (Pichincha and Loja) by performing physicochemical and spectroscopic analyses. For this study 25 samples were collected from different places and markets and characterized by water, sucrose, reducing sugars and electric conductivity measurement. Also, their Raman and Infrared (IR) spectra were recorded and analysed using a Principal Component Analysis (PCA) in order to verify the quality of the honeys. In addition, a screening of several pesticides was performed in order to verify possible chemical threats to human health and honey bees. It was found that 8 samples have a deviation from the Standard established parameters. Two of them have a high difference in the content of sucrose and reducing sugars, which are located deviated from all the other samples in the PCA of the applied vibrational spectroscopy (IR/Raman), shaping two clear clusters. The results show that Raman and IR spectroscopy is appropriate techniques for the quality control of honey and correlates well with the physicochemical analyses.

Cell wall materials (CWMs) from sweetpotato, cassava, and potato starch residues were degraded using a crude enzyme solution from the culture filtrate of a Bacillus sp. isolated from soil, Bacillus sp. M4. This organism has been found to secrete polygalacturonic acid lyase (PGL) and glycan depolymerase activities, especially arabinanase, but cellulase activity was nearly absent. Sugar analysis of the solubilized product after enzyme treatment at pH 7.0 revealed that it is mainly composed of galacturonic acid, galactose, and arabinose, the sugars found commonly in the pectin fraction. This suggested the presence of a protopectinase (PPase) activity in the culture filtrate. The presence of EDTA completely inhibited PGL but PPase activity was almost retained, suggesting that the PGL is not the primary activity responsible for pectin solubilization. The mode of action of the crude enzyme was determined by terminal sugar analysis using HPAEC-PAD after hydrolysis of the reduced products. Results revealed that galactose is the main neutral sugar at the reducing terminal of the products, although rhamnose was also present in the higher molecular weight component. This suggested that at neutral pH, the primary activity in the culture filtrate of Bacillus sp. M4 is a B-type PPase, which attacked the galactan as well as rhamnogalacturonan moieties of the protopectin, resulting in the release of a soluble pectin fraction.

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Con la finalidad de contar con un tratamiento biológico alternativo al uso de los fertilizantes químicos se evaluó el potencial biofertilizantes de consorcios de cianobacterias asilados de tapetes bacterianos recolectados en el volcán Pasochoa. Se reportó la influencia del biofertilizante en el crecimiento y valor nutricional de Pasto Raygrass, empleado comúnmente en la alimentación de ganado.