Physicochemical properties of heat-moisture treated, sodium stearate complexed starch: The effect of sodium stearate concentration

Amylose‑sodium stearate (SS) complexes (2, 5 and 8%) in heat-moisture treated potato starch (HPS) were evaluated for their physicochemical properties. Based on the DSC thermograms, the amylose - SS complexes were successfully formed with high thermal stability, indicated by a melt temperature (T_peak) of ≥ 112 °C for type I and ≥125 °C for type II complexes. Addition of 2% SS resulted in a single endothermal peak of the complexes, while 5 and 8% led to the formation of type I and II complexes with much higher enthalpy (ΔH) values. The XRD curve confirmed that the complexes were successfully formed. The pasting temperature increased from 66 °C for native to 91 °C for HPS145 complexed starch with 5% SS. Furthermore, the swelling power could be largely decreased, and the granular structure preserved. In addition, the inclusion complexation with SS on (HPS) succesfully improved the cook stabiliy.

Cobalt chromium-layered double hydroxide, α- and β- Co(OH)2 and amorphous Cr(OH)3: synthesis, modification and characterization

Cobalt-chromium layered double hydroxide (CoCr LDH), α- and β- Co(OH)₂ and amorphous Cr(OH)₃ have been synthesized under different reaction conditions. The obtained CoCr LDH was modified by stearic acid (SA) and sodium stearate (SS). The obtained samples have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Ultraviolet-visible- (UV-Vis), Fourier transform infrared- (FTIR) and Energy-dispersive X-ray- (EDX) spectroscopy. The influence of reaction conditions on product composition, structural and optical properties of the samples have been discussed in detail. The basal spacing of CoCr-LDH increased from 7.366 Å to 7.428 Å and 25.214Å after the intercalation by stearic acid and sodium stearate, respectively. The average particles size by SEM analyze was estimated to be approximately 100-150 nm and 30-50 nm for CoCr-LDH_0.6M(90°C) and CoCr-LDH_0.6M(90°C)/SS nanostructures, respectively. Mixed hydroxides like α- and β- Co(OH)₂ have been obtained along with LDH at lower pH value (pH ∼ 7). The number of diffraction peaks corresponding to β-Co(OH)₂ has increased with relatively decreasing of Co²⁺ ions in the reaction medium. At high chromium concentrations (Co²⁺:Cr³⁺ = 1:3 and 1:5), amorphous Cr(OH)₃ were formed in the experiment.

Synthesis, characteristics and evaluation of antioxidant activity of [1-(tannin-ether)-ethyl]stearate

The [1-(tannin-ether)-ethyl]stearate (TEES) was synthesized by two-stage process successfully. 1-Chloroethyl tannin ether (CTE), as an intermediate, was initially prepared with tannic acid (TA) and paraldehyde. Then, the TEES was synthesized by sodium stearate and CTE in the presence of FeCl3-PEG-400 as phase-transfer catalyst. Synthetic conditions were optimized. The structural characteristics of TEES were analyzed by FTIR, 1H NMR and UV-vis techniques. And the thermal stability of TEES was investigated. Moreover, the antioxidant activity of TEES for linseed oil was evaluated and compared with other substance such as TA and butylated hydroxyanisole (BHA). The results showed that the yield reached 88.19 wt% (theoretical value: 88.80 wt%, relative deviation: 0.80 ± 0.34%) under the optimized condition, in which the ratio of TA: FeCl3: PEG-400 was 1 g: 0.09 g: 0.693 mL, the reaction temperature and time was 75 °C and 240 min, respectively. The antioxidant activity of TEES was higher than TA and comparable to BHA in linseed oil. The POV of oil samples with TEES, TA and BHA were 63.4, 201.3 and 84.2 meq/kg after 20 days, respectively. The reason of this was relate to the better oil solubility of TEES and its unique structure. More importantly, the interaction between the TEES and SC was weaker than that of TA and SC by the fluorescence experiment.