Fabrication and characterization of soy β-conglycinin-dextran-polyphenol nanocomplexes: Improvement on the antioxidant activity and sustained-release property of curcumin

In this study, glycated soy β-conglycinin (β-CG) stabilized curcumin (Cur) composites were fabricated by a unique reversible self-assembly character of β-conglycinin-dextran conjugates (β-CG-DEX). Intrinsic fluorescence and far-UV CD spectra revealed that glycation did not affect the self-assembly property of β-CG in the pH-shifting treatment. The structure of β-CG-DEX could be unfolded at pH 12.0 and reassembled during acidification (from pH 12.0 to 7.0). Meanwhile, β-CG-DEX-3d, which was incubated at 60 °C for 3 days, exhibited a high loading capacity (123.4 mg/g) for curcumin, which far exceeds that (74.90 mg/g) of β-CG-Cur. Moreover, the reassembled β-CG-DEX-3d-Cur showed eminent antioxidant activity of approximately 1.5 times higher than that of free curcumin. During the simulated gastrointestinal condition, compared with β-CG-Cur, β-CG-DEX-3d-Cur nanoparticles showed a more stable and sustained release of curcumin. Thus, β-CG-DEX has immense potential to become a new delivery carrier for hydrophobic food components by means of a self-assembly strategy.

Effect of centrifugal pre-treatment on flavor change of cloudy orange juice: Interaction between pectin and aroma release

Cloud loss of orange juice could be effectively inhibited by centrifugal treatment, but it can induce flavor changes, which become a new challenge for the industry. This work aims to investigate the effect of centrifugation on flavor changes in orange juice and explore its possible mechanism. Taste- and aroma-related attributes were analyzed, and pectin was characterized. Results indicated that pH (4.00), total soluble solid (9.67 °Brix), titratable acidity (0.42%), sucrose (44%), fructose (29%), and glucose (27%) were less affected by centrifugation (P > 0.05). However, aroma compounds significantly changed (P < 0.05), where terpenes and alcohols tended to be distributed in pulp and serum after centrifugation, respectively. Pearson correlation analysis showed that aroma compound distribution induced by centrifugation was highly related to chelator-solubilized pectin fraction and sodium carbonate-solubilized pectin fraction (|R| > 0.9). In general, centrifugation clearly changed aroma of orange juice, which was mainly affected by pectin characteristics.

Study of fucoidans as natural biomolecules for therapeutical applications in osteoarthritis

Osteoarthritis (OA) is the most prevalent articular chronic disease. Although, to date there is no cure for OA. Fucoidans, one of the main therapeutic components of brown algae, have emerged as promising molecules in OA treatment. However, the variability between fucoidans makes difficult the pursuit of the most suitable candidate to target specific pathological processes. By an in vitro experimental approach in chondrocytes and fibroblast-like synoviocytes, we observed that chemical composition of fucoidan, and specifically the phlorotannin content and the ratio sulfate:fucose, seems critically relevant for its biological activity. Nonetheless, other factors like concentration and molecular weight of the fucoidan may influence on its beneficial effects. Additionally, a cell-type dependent response was also detected. Thus, our results shed light on the potential use of fucoidans as natural molecules in the treatment of key pathological processes in the joint that favor the development of rheumatic disorders as OA.

Structural, thermal and rheological properties of gluten dough: Comparative changes by dextran, weak acidification and their combination

Dextran-containing sourdough has been exploited in breadmaking, obtaining additive-free bread of high quality. Effect of dextran, weak acidification and their association on gluten dough structure, thermal properties and rheology was investigated. Electrophoresis (SDS-PAGE) showed that dextran and acids both lowered the band intensity in the high molecular weight area (Mw > 175 kDa) and size exclusion (SE-HPLC) revealed that weak acidification induced a decrease of 4.73% of the glutenin macropolymer (GMP) content. The higher free thiol (SH) was observed after dextran addition, further suggesting the hindered glutenin polymerization. Fourier transform infrared spectroscopy (FTIR) found that dextran and weak acidity caused increased β-turn and decreased β-sheet structures, suggesting a gluten of lower coherence and resistance to extension. Weakened thermal stability and viscoelasticity were subsequently detected by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic rheology. However, structural, thermal and rheological properties of the weakly acidified group were improved by the associated dextran.

Effects of ultrasound irradiation on the characterization and bioactivities of the polysaccharide from blackcurrant fruits

In this study, the influence of ultrasound irradiation on the characterization and bioactivities of the polysaccharide from blackcurrant fruits (BCP, molecular weight: M_w = 3.26 × 10⁴ kDa) was investigated. Two degraded polysaccharides (U-400, M_w = 1.89 × 10⁴ kDa, and U-600, M_w = 1.32 × 10⁴ kDa) were obtained by different ultrasound powers of 400 W and 600 W, respectively. Compared with BCP, U-400 and U-600 showed 63.52% and 68.85% reductions in the particle size (Z_avg), respectively; moreover, the dynamic viscosity of BCP was reduced by 27.88%, and 33.63%, separately. The reducing sugar content and thermal stability increased with the increase of ultrasound intensity. The degraded polysaccharides contained the same monosaccharide species as those of BCP but at different molar ratios. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic analysis confirmed that the degraded polysaccharides and BCP exhibited the similar structural features, which were mainly composed of six glycosidic bonds. A reduction in surface area of the flake-like structure was observed in the degraded polysaccharides compared to that of BCP, and they had no triple helix structure. Furthermore, the precise structural characteristics of U-600 were identified by 2D NMR analysis. The results of the bioactivity assays indicated that the ultrasound irradiation could evidently enhance the antioxidant (hydroxyl and superoxide radicals scavenging, lipid peroxidation inhibition, and DNA damage protection activities), α-amylase and α-glucosidase inhibition activities of BCP. These activities increased in the order of U-600 > U-400 > BCP. In particular, the DNA protection and α-amylase inhibition activities for U-600 were 52.19 ± 1.34% and 75.98 ± 0.77%, respectively, which were 2 times higher than those of BCP. U-600 prepared with the higher-intensity ultrasound exhibited the best physicochemical properties and bioactivities among the three polysaccharides. These results suggested that ultrasound irradiation was an efficient, green method to produce value-added polysaccharide for use in functional food or medicine.