Behavior of Peruvian carrot (Arracacia xanthorrhiza) and cassava (Manihot esculenta) starches subjected to the heat-moisture treatment

Peruvian carrot and cassava starches were isolated, adjusted to 30 and 35% moisture, and heatedat 90°C for 8 h. Structural and physicochemical characteristics of the treated starches wereevaluated and compared. High performance anion exchange chromatography with pulsedamperometric detector (HPAEC-PAD), gel permeation chromatography (GPC), and amylosecontent, revealed that the HMT did not change the chemical structures of the starches. A largeagglomeration of granules was observed from SEM, particularly in the Peruvian carrot starch.Crystalline patterns in Peruvian carrot and cassava starches changed from B to C and CAto A,respectively. Relative crystallinity decreased from 30 to 25% in Peruvian Carrot starch, andincreased from 35 to 37% in cassava starch adjusted to 30% moisture. SF and peak viscositydecreased, breakdown was almost completely eliminated (particularly in the Peruvian carrotstarch), and final viscosity increased. WAI and WSI increased as moisture levels of bothstarches increased. Gelatinization temperatures increased and enthalpy decreased. Degrees ofgelatinization increased as the moisture level increased, reaching 33 and 72% in the cassavaand Peruvian carrot starches, respectively. HMT strengthened the intra- and intermolecularinteractions of starches and increased their stability during heating and shearing, but also causeda partial gelatinization in the starches, particularly in Peruvian carrot starch.

New insights into the structural characteristics of irradiated crotamine

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Overexpression of mitochondrial uncoupling protein 1 (UCP1) induces a hypoxic response in Nicotiana tabacum leaves

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characterization of the hemoglobins and globins of Synbranchus marmoratus Bloch, 1795 (Pisces, Synbranchidae)

1. 1. Total hemolysates of Synbranchus marmoratus Bloch, 1795, captured in Vitoriana, district of Botucatu, State of São Paulo, Brazil, were submitted to agar-starch gel electrophoresis on glass slides using 42 mM-Tris 1.7 mM EDTA-6.1 mM borate buffer, pH 8.8, for the gel and 10 mM borate-1.7 mM NaOH buffer, pH 8.6, for the cuvette. 2. 2. Three distinct hemoglobin bands were detected, with Hb I being of the cathodic type. 3. 3. Cellulose acetate electrophoresis in 800 mM Tris-2.1 mM EDTA buffer, pH 8.9, containing 6 M urea and 2.25 mM β-mercaptoethanol indicated the presence of four globin chains denoted α 1, α 2, β and γ. 4. 4. It is suggested that the probable tetrameric constitution of the hemoglobin of Synbranchus marmoratus Bloch, 1795 is Hb I (α 2 2γ 2), Hb II (α 2 1γ 2) and Hb III (α 2 1β 2). © 1986.

Validation of a HPLC method for determination of glutamine in food additives using post-column derivatization

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of the betaine content of feed ingredients using high-performance liquid chromatography

A series of studies was conducted to establish a methodology for the accurate and efficient determination of betaine in different feed ingredients. The final methodology involves an extraction step in which the feed sample is heated for 3h in a methanolic KOH solution using a Goldfisch apparatus. Impurities are removed by the addition of activated charcoal and concentrated (36%) HCl. After centrifugation the extractant is passed through a strong cation exchange resin (Dowex 50W-X12, H+). The betaine retained in the column is eluted with 1.5 N HCl. A 2 nil aliquot of the elute is air dried and reconstituted with 1 ml of deionised water. HPLC separation with a cation exchange column (Partisil SCX-10) is used for the separation of betaine from other compounds. The mobile phase is kept constant at 50mm KH2PO4 in water, and eluted compounds are detected by UV absorbance (200nm). The flow rate is maintained at 1.5ml min(-1). This assay is very accurate over the range of betaine concentrations from 15 to 650 mug ml(-1), with a lower detection limit in feeds of approximately 500 mug g(-1) when 4g of sample is extracted. Recovery assays done with standard betaine hydrochloride and hard red wheat resulted in a consistent recovery of 80%. Betaine content was quantified in several feed ingredients, including alfalfa (1.77 mg kg(-1)), wheat (3.96 mg kg(-1)), wheat middlings (4.98 mg kg(-1)) and poultry meal (0.77 mg kg(-1)). Betaine in corn and soybean meal was not detectable by this method, even when 16g of sample was used (<125 mg kg(-1)). Betaine present in several feed ingredients should influence choline supplementation to animal feeds and may have implications for human health. (C) 2002 Society of Chemical Industry.