PROFIL GELATINISASI DAN KOMPONEN ANTIOKSIDAN TEPUNG KETAN HITAM TERMODIFIKASI DENGAN ANNEALING

This research aims to study and characterize the effect of the annealing conditions (temperature and heating duration) on the gelatinization profile and antioxidant components of annealing-modified black glutinous rice flour (ABGRF). This experiment used a 2x3 factorial design consisted of temperature factor (54 and 58°C) and heating duration factor (4, 5, and 6 hours) with 2 replications. Research results showed that both factors and their interactions significantly affected all parameters of the gelatinization profile and antioxidant component of ABGRF (except through viscosity). Compared to its native, ABGRF showed an increase in peak viscosity, through viscosity (except treatment 54°C:5 hours), peak time and pasting tem-perature, indicated ABGRF resistance improvement to the heating process. Generally, the temperature treatment increment increased breakdown, setback, and final viscosity, but the heating duration increment decreased those values. The variation of ABGRF gelatinization profiles increased the diversification potential of BGRF-based food products. Annealing caused an overall decrease in ABGRF antioxidant ability. ABGRF produced by 54°C:4 hours treatment had the highest amount of antioxidant components (total anthocyanins contents 103.78±2.24 mg C3GE/100 g, total phenolic compounds 241.65±1.98 mg GAE/100 g, DPPH 267.14± 3.23 mg AAE/100 g, FRAP 473.94±1.43 mg AAE/100 g), thus using it as ingredients in functional food is more recommended, especially as composite flour for bread and cake.

Dual-frequency ultrasound for ultrasonic-assisted esterification

The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X-ray, RVA, DSC, freeze-thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X-ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (ΔH gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze-thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz ˃ 25 kHz ˃ 40 kHz ˃ N starch).

Dual-frequency ultrasound for ultrasonic-assisted esterification

The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X-ray, RVA, DSC, freeze-thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X-ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (ΔH gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze-thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz ˃ 25 kHz ˃ 40 kHz ˃ N starch).

Preparation and characterization of pH-sensitive methyl methacrylate-g-starch/hydroxypropylated starch hydrogels: in vitro and in vivo study on release of esomeprazole magnesium

In the present study, novel hydrogels were prepared through graft copolymerization of methyl methacrylate onto starch and hydroxypropylated starch for intestinal drug delivery. The successful grafting has been confirmed by FTIR, NMR spectroscopy, and elemental analysis. Morphological examination of copolymeric hydrogels by scanning electron microscopy (SEM) confirms the macroporous nature of the copolymers. The high decomposition temperature was observed in thermograms indicating the thermal stability of the hydrogels. To attain a hydrogel with maximum percent graft yield, the impact of reaction variables like concentration of ceric ammonium nitrate as initiator and methyl methacrylate as monomer were consistently optimized. X-ray powder diffraction and differential scanning calorimetric analysis supported the successful entrapment of the drug moiety (esomeprazole magnesium; proton pump inhibitor) within the hydrogel network. Drug encapsulation efficiency of optimized hydrogels was found to be >78%. Furthermore, swelling capacity of copolymeric hydrogels exhibited a pH-responsive behavior which makes the synthesized hydrogels potential candidates for controlled delivery of medicinal agents. In vitro drug release was found to be sustained up to 14 h with 80-90% drug release in pH 6.8 solution; however, the cumulative release was 40-45% in pH 1.2. The gastrointestinal transit behavior of optimized hydrogel was determined by gamma scintigraphy, using (99m)Tc as marker. The amount of radioactive tracer released from the labeled hydrogel was minimal when the hydrogel was in the stomach, whereas it increased as hydrogel reached in intestine. Well-correlated results of in vitro and in vivo analysis proved their controlled release behavior with preferential delivery into alkaline pH environment.