RESUMO
Deuterium labelling of the non-labile protium atoms in starch granules has been achieved for the first time, by growing genetically modified yeast on deuterated media. Mass spectrometry of the glucose monomers from digested starch showed 44 % average deuteration of the non-labile protium when grown on partially deuterated raffinose (with average deuteration 48 %); yielding starch with 26 % average overall deuteration. Non-labile deuteration was also demonstrated using D2O solvent in the culture medium. Solid-state NMR revealed that deuteration was not evenly distributed across the monomer, being highest at the C6 carbon and lowest at the C1 carbon. SANS revealed two structural features at q = 0.05 Å-1 and 0.4 Å-1, the first corresponding to a lamellar repeat of approximately 12-13 nm while the latter is consistent with B-type crystalline polymer packing. Furthermore, solvent contrast variation SANS analysis yielded a contrast match point of 66 mol% D2O indicative of approximately 30-35 % average deuteration of the bulk granules, consistent with mass spectroscopy. When coupled with the more traditional process of exchange of labile protium in the hydroxyl groups by D2O solvent exchange, the biosynthesis of highly deuterated starch opens new opportunities for neutron scattering experiments involving multicomponent starch-based systems.
Assuntos
Deutério , Amido , Amido/química , Amido/metabolismo , Amido/biossíntese , Deutério/química , Saccharomyces cerevisiae/metabolismo , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Rafinose/química , Rafinose/metabolismoRESUMO
The presence of antinutrients and undesirable flavours in kidney bean flour poses challenges to consumer acceptance. Although extrusion can mitigate antinutrients to some extent, its impact on reducing beany flavour in bean flour remains underexplored. This study investigated the effects of injecting acetic acid or sodium carbonate solutions at three concentration levels (0.05, 0.1, 0.15 mol/L), in conjunction with three temperature profiles (40/60/80/80/90, 40/60/80/90/110, 50/70/90/110/130 °C) and two feed moisture levels (25, 30 %), on the removal of antinutrients (condensed tannins, trypsin inhibitor activity, phytic acid, raffinose family oligosaccharides) and reduction of volatile compounds that contribute to beany flavour in whole kidney bean flour. The results showed that all concentrations of acetic acid and sodium carbonate solutions effectively reduced condensed tannins compared to water, especially at 130 °C extrusion temperature. Introducing acetic acid and sodium carbonate solutions at a concentration of 0.15 mol/L led to 72 and 90 % reduction of total raffinose family oligosaccharide content, respectively, in contrast to the 17 % reduction observed with water alone. The incorporation of sodium carbonate solution reduced the total volatile compounds by 45-58 % as compared with water (23-33 %) and acetic acid (11-27 %). This reduction was primarily due to the reduction of aldehydes, alcohols, and aromatic hydrocarbons. These results indicate that injecting sodium carbonate solution during extrusion can effectively reduce antinutrients and beany flavour compounds in kidney bean flour.
Assuntos
Ácido Acético , Carbonatos , Farinha , Manipulação de Alimentos , Phaseolus , Ácido Fítico , Paladar , Farinha/análise , Carbonatos/química , Manipulação de Alimentos/métodos , Ácido Fítico/análise , Phaseolus/química , Proantocianidinas/análise , Rafinose/química , Temperatura , Concentração de Íons de Hidrogênio , Compostos Orgânicos Voláteis/análiseRESUMO
The study investigates the efficacy of an enzymatic preparation primarily with α-galactosidase activity for improving the quality of white sugar from poor-quality sugar beets. Focused on overcoming raffinose accumulation challenges in sugar beets, especially those harvested prematurely or stored for extended periods, an innovative exploration of enzymatic application in an industrial setting for the first time was conducted. By integrating theoretical calculations and experimental data, the findings reveal that α-galactosidase preparation notably diminishes raffinose content in beet juice, thus enhancing the sucrose yield and overall sugar quality. A reliable method to process lower-quality beets, promising enhanced efficiency in sugar production, was presented. The study also highlights the economic benefits of incorporating enzyme preparation into the production process, demonstrating a notable return on investment and underscoring the potential of enzymatic treatments to address industry challenges.
Assuntos
Beta vulgaris , Rafinose , alfa-Galactosidase , Rafinose/química , Rafinose/metabolismo , Beta vulgaris/química , alfa-Galactosidase/metabolismo , alfa-Galactosidase/química , Açúcares/química , Açúcares/metabolismo , CatáliseRESUMO
Soaking pulses in water is a traditional practice widely used both by many households and by the food industry, and depending on the specific conditions used, can effectively reduce α-galactosides. Monitoring changes in α-galactoside content in pulses under different steeping conditions can provide insights into the degradation mechanisms and help overcome the barrier to consumption caused by digestive problems. In this study, we analyzed the impact of steeping at different temperatures (30, 45, 60, 75, and 90 °C) and at different pH (4.0, 5.0, and 6.0) on α-galactosides content in chickpeas, lentils, and beans. Our results showed that the lower the pH, the faster the α-galactosides were reduced. Moreover, steeping at lower temperatures (30 °C and 45 °C) favored hydrolysis of α-galactosides, whereas steeping at higher temperatures (60, 75, and 90 °C) favored diffusion. Soaking at 45 °C at a pH of 4.0 for 3 h resulted in acceptable levels of α-galactosides (less than 1 g/100 g), i.e. a reduction of up to 65 % in chickpeas, 85 % in lentils, and 52 % in beans.
Assuntos
Cicer , Lens (Planta) , Oligossacarídeos , Rafinose , Temperatura , Concentração de Íons de Hidrogênio , Hidrólise , Rafinose/química , Rafinose/análise , Oligossacarídeos/química , Oligossacarídeos/análise , Lens (Planta)/química , Cicer/química , Manipulação de Alimentos/métodos , Galactosídeos/química , DifusãoRESUMO
A series of intricate and dynamic physiological healing processes are involved in the healing of skin wounds. Herein, a multifunctional hydrogel is firstly designed and constructed by L-arginine-grafted O-carboxymethyl chitosan (CMCA), catechol-modified oxidized hyaluronic acid (DOHA), and dopamine nanoparticles (pDA-NPs). pDA-NPs were loaded in hydrogel for inherently powerful antimicrobial properties and could be as a cross-linking agent to construct hydrogels. Raffinose (Raf) was further incorporated to obtain CMCA-DOHA-pDA2@Raf hydrogel for its function of modulating epidermal differentiation. The hydrogel has good physicochemical properties and could promote cell proliferation and migration, which shows superior hemostatic capabilities in animal models of hemorrhage. The hydrogel significantly promoted wound healing on rat skin defect models by upregulating VEGF and CD31 and decreasing IL-6 and TNF-α, stimulating neovascularization and collagen deposition in epithelial structures. This multifunctional hydrogel implies the potential to be a dynamic wound dressing.