Chemical profiles of three varieties of germinated rice based on LC-MS and their antioxidant activity

In this study,chemical profiles in different germinated rice extracts (GREs) using different solvent extraction ratio were investigated.Three varieties of germinated rice (GR), including germinated white rice(GWR), germinated black rice (GBR) and germinated red rice(GRR) were extracted using 70and 100% ethanol(v/v). Both extracts were characterized for their chemical profiles using liquid chromatography-electrospray ionization−quadrupole−time−of−flight mass spectrometry (LC−ESI−Q−TOF−MS). The content of γ−aminobutyric acid (GABA), total phenolic content (TPC), and antioxidant activities were also determined. The chemical profiles of GREs are composed of organic acids, amino acids, vitamins, flavonoids,and phenolic compounds. The GABA content of all rice varieties presented the same pattern in both ethanolic extracts. The TPC of GRE extracted by 70% ethanol (v/v) showed significant higher amount than that in the 100%v/vethanolic extract(p<0.05). The highest TPC was obtained from GBR, followed by GRR and GWR, respectively(p<0.05). The antioxidant activity from three assays, including DPPH, ABTS, and FRAP showed higher activities in the 100% v/vethanolic extracts than their 70% v/v counterparts(p<0.05). The phenolic content showed a low positive Pearson correlation with antioxidant activities, however,the strong positive Pearson’s correlation coefficients were observed among these activities (r= 0.846-0.935). The results suggested that the GR was composed of potential bioactive compounds such as GABA and other phytochemical contents possessing high antioxidant bioactivity which can be used as functional food or as part of nutraceutical products

Utilization of Layer-by-Layer Interfacial Deposition Technique to Improve Freeze-Thaw Stability of Oil-in-Water Emulsions

The freeze–thaw stability of 5 wt% hydrogenated palm oil-in-water emulsions (pH 3) containing droplets stabilized by sodium dodecyl sulfate (SDS)–chitosan–pectin membranes was studied. The multilayered interfacial membranes were created using an electrostatic layer-by-layer deposition method. The ζ-potential, mean particle diameter, fat destabilization, apparent viscosity and microstructure of the emulsions were used to examine the influence of freezing on their stability. Emulsions containing oil droplets stabilized only by SDS were highly unstable to droplet coalescence when either the oil phase became partially crystallized or the water phase crystallized. Emulsions containing oil droplets stabilized by SDS–chitosan membranes were stable to droplet coalescence, but unstable to droplet flocculation. Emulsions containing droplets stabilized by SDS–chitosan–pectin membranes were stable to both droplet coalescence and flocculation. The interfacial engineering technology utilized in this study could lead to the creation of food emulsions with improved stability to freeze–thaw cycling