A História da Alimentação: balizas historiográficas

Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

Localization and dynamics of amylose-lipophilic molecules inclusion complex formation in starch granules

Inclusion complex formation between lipophilic dye molecules and amylose polymers in starch granules is investigated using laser spectroscopy and microscopy. By combining confocal laser scanning microscopy (CLSM) with spatial resolved photoluminescence (PL) spectroscopy, we are able to discriminate the presence of amylose in the peripheral region of regular and waxy granules from potato and corn starch, associating a clear optical fingerprint with the interaction between starch granules and lipophilic dye molecules. We show in particular that in the case of regular starch the polar head of the lipophilic dye molecules remains outside the amylose helix experiencing a water-based environment. The measurements performed on samples that have been extensively washed provide a strong proof of the specific interaction between lipid dye molecules and amylose chains in regular starch. These measurements also confirm the tendency of longer amylopectin chains, located in the hilum of waxy starch granules, to form inclusion complexes with ligands. Through real-time recording of CLSM micrographs, within a time frame of tens of seconds, we measured the dynamics of occurrence of the inclusion process between lipids and amylose located at the periphery of starch granules

Assessment of the influence of amylose-LPC complexation on the extent of wheat starch digestibility by size-exclusion chromatography

<p>Amylose forms inclusion complexes with lysophosphatidylcholine (LPC), that decrease the susceptibility of amylose to amylase degradation. This study on the influence of complexation on starch susceptibility to amylase explains the nature of this protective effect. Wheat starch suspensions (9% w/w) containing 0.5-5% LPC were subjected to hydrolysis by porcine pancreatic a-amylase at 37 degrees C for several digestion times. The digesta were analysed by size-exclusion chromatography (SEC). The molar mass distribution was closely dependent on the digestion time and amount of LPC. This study precisely demonstrates the alteration of the digestion profile of starch on a molecular level, influenced by amylose-LPC complexation; however the effect depends on the digestion time. During 15 and 30 min digestion, inclusion complexes not only protect amylopectin in the initial hydrolysis stage, but also demonstrate lower susceptibility of the molecular amylose complexes to amylase hydrolysis. Digestion for 240 min resulted in a lower oligosaccharide peak concentration, in the presence of a high LPC concentration, which is related to less degradation of complexed amylose fraction. (C) 2013 Elsevier Ltd. All rights reserved.</p>

Influence of lysophosphatidylcholine on the gelation of diluted wheat starch suspensions

<p>Starch is an omnipresent constituent which is used for its nutritional and structuring properties. Recently concerns have been raised since starch is a source of readily available glucose which is tightly correlated with diabetes type II and obesity. For this reason, the possibilities for modulating the digestibility of starch while preserving its functional properties were investigated; therefore the focus of this paper is on starch gelatinization and the effect of lysophosphatidylcholine (LPC) on the structuring properties of wheat starch. The effect of LPC on thermal properties and viscosity behavior of starch suspensions was studied using DSC and RVA, respectively. The influence on granular structure was observed by light microscopy. The RVA profile demonstrated no viscosity increase at high LPC concentrations which proves intact granular structure after gelatinization. LPC in intermediate concentrations resulted in a notable delay of pasting; however the peak and end viscosities were influenced as well. Lower LPC concentrations demonstrated a higher peak viscosity as compared with pure starch suspensions. DSC results imply that inclusion complexes of amylose LPC might be formed during pasting time. Since the viscosity profiles are changed by LPC addition, swelling power and solubility of starch granules are influenced as well. LPC hinders swelling power and solubility of starch granules which are stimulated by heating. (C) 2012 Elsevier Ltd. All rights reserved.</p>

High performance alkyd resins synthesized from postconsumer PET bottles

The glycolytic recycling of waste PET presents a challenge for the production of secondary value-added products, such as alkyd resins. A way to overcome the unsatisfactory mechanical, drying and chemical resistance properties of alkyds obtained from difunctional glycolyzates was proposed. Waste PET was glycolyzed using multifunctional alcohols: glycerol (G), trimethylolethane (TME), trimethylolpropane (TMP) and pentaerythritol (PE), giving tetra- and hexa-functional glycolyzates and, for comparison, using diethylene glycol (DEG), propylene glycol (PG) and dipropylene glycol (DPG) giving di-functional glycolyzates. The obtained glycolyzates were examined by 1H and 13C NMR, FTIR spectroscopy and elemental analysis and further used in the synthesis of alkyd resins. The properties of the prepared alkyd resins (acid, hydroxyl and iodine values, color, average molar masses and molar mass distributions, viscosity, drying time, hardness, flexibility, gloss, adhesion and chemical resistance) were investigated with respect to the functionality and the structure of the used glycolyzates. Alkyd resins derived from multifunctional glycolyzates (TME and TMP) showed considerably enhanced properties compared to those produced from difunctional glycolyzates and also to conventional general purpose resins

Lipase-Catalyzed Ring-Opening Copolymerization of ε‑Caprolactone and β‑Lactam

The enzymatic ring-opening copolymerization of ε-caprolactone (ε-CL) and β-lactam by using Candida antarctica lipase B (CAL-B) as catalyst was studied. Variation of the feed ratios of 25:75, 50:50, and 75:25 of ε-CL/β-lactam was performed. The products contain poly­(ε-CL-<i>co</i>-β-lactam) and the homopolymers of poly­(ε-CL) and poly­(β-lactam). The structure of the copolymers was determined by MALDI-ToF MS. Poly­(ε-CL-<i>co</i>-β-lactam) has an alternating and random structure consisting of alternating repeating units with oligo­(ε-CL) or oligo­(β-lactam). The highest fraction of the alternating copolymers resulted from the reaction with a feed ratio 50:50. The copolymer is a semicrystalline polymer with a <i>T</i>_m at 124 °C and <i>T</i>_gs at −15 and 50 °C. Interestingly, the copolymer also demonstrated cold crystallization at 29 and 74 °C, after quenching the sample from the melt in liquid nitrogen

The influence of amylose-LPC complex formation on the susceptibility of wheat starch to amylase

<p>This study was aimed to assess the role of lysophosphatidylcholine (LPC) in the development of slowly digestible starch (SOS). The influence of LPC, on the enzymatic degradation of diluted 9% wheat starch suspensions (w/w) was investigated, using an in vitro digestion method. Wheat starch suspensions containing 0.5-5% LPC (based on starch) were heated in a Rapid Visco Analyser (RVA) till 95 degrees C and subjected to enzyme hydrolysis by porcine pancreatic a-amylase at 37 degrees C for several digestion periods. In vitro digestion measurements demonstrated that complexing starch with 5% LPC leads to a 22% decrease in rate of reducing sugar compared to the reference while the samples containing 0.5% LPC showed an equal digestibility comparable to the control. A clear decrease in the formation of reducing sugars was observed in presence of 2-5% LPC, since the results after 15 min digestion imply the formation of SDS due to the formation of amylose-LPC inclusion complexes. The DSC measurements proved the presence of amylose-LPC inclusion complexes even after 240 min digestion demonstrating the low susceptibility of amylose-V complexes to amylase. (C) 2013 Elsevier Ltd. All rights reserved.</p>