Xiaohong Lan

Effects of high hydrostatic pressure and high pressure homogenization processing on characteristics of potato peel waste pectin

To better understand the effects of high pressure processing on potato peel waste pectins, the structural characteristics, physicochemical properties, and morphological features of the pectin treated with high hydrostatic pressure (HHP) and high pressure homogenization (HPH) at 200 MPa for 5 min were studied. The potato peel waste pectins subjected to high pressure treatments exhibited increased galacturonic acid contents as well as decreased esterification degree, (Gal + Ara)/Rha ratio, and molecular weight. Furthermore, the potato peel waste pectins treated with high pressure had an increased viscosity and improved emulsifying properties. The morphological features, determined by atomic force microscopy, shown the degradation of side chains of the pectin induced by high pressure treatments. The results suggest that high pressure processing is an efficient technique to modify pectin from potato peel waste to a thickener or stabilizer agent, but high pressure homogenization shows a better effect.

The effect of temperature on the physicochemical properties and lamellar structure of canna starch subjected to enzymatic degradation

Canna starch was degraded thermally and enzymatically with or without α-amylase (Bacillus subtilis) at increasing temperatures (50–60 °C). Considerable disruption of the starch granules was found in enzymatically degraded canna starch (EDCS) compared to native canna starch (NCS), while only some swollen starch granules were observed in thermally degraded canna starch (TDCS) even at the critical gelatinization temperature (60 °C). With respect to physicochemical properties, both thermal and enzymatic degradation reduced the swelling power (SP) due to the internal rearrangements within the starch granules. Increased temperature narrows the gelatinization range of canna starch subjected to thermal and enzymatic degradation, however these treatments have different effects on the enthalpy. Small angle X-ray scattering (SAXS) investigation reveals that the lamellar order becomes less pronounced with enhanced temperature, both in TDCS and EDCS, however, a reduced ΔL from the correlation function indicates that the lamellar thickness distribution of TDCS and EDCS are narrower than their native counterpart.

Application of two-phase lamellar model to study the ultrastructure of annealed canna starch: A comparison with linear correlation function

Canna starch was annealed at sub-gelatinization temperature (50°C) with different annealing time. Small angle X-ray scattering (SAXS) was used to estimate the ultrastructure of the annealed starches with the combined two-phase lamellar model and one-dimensional correlation function. The results showed that, upon annealing, water preferably swelled the amorphous regions of canna starch granules while maintained the part of crystalline region, resulted in an increase in amorphous thickness (da) and lamellar repeat distance (d). Power law plots indicates that a mass fractal (self-similar) structure was observed in canna starch, and annealing induces a less compact structure compared to native canna starch (NCS). Correlation analysis showed that no correlation was existed between annealing time and lamellar peak area, width of peak, and volume crystallinity. However, due to the initial degradation of the amorphous region, the volume crystallinity increased significantly with the increase of crystalline thickness (dc).

Investigating lignin from Canna edulis ker residues induced activation of α-amylase: Kinetics, interaction, and molecular docking

The lignin isolated from C. edulis ker residues showed a significant activating effect on α-amylase. Further studies revealed that the isolated lignin formed a 1:1 complex with α-amylase through hydrogen bonding and quenched fluorescence of α-amylase with a static quenching procedure. Binding with lignin led to conformational and granular size changes of α-amylase. Two-dimensional nuclear Overhauser spectroscopy (2D-NOESY) spectra suggested that OH in G units and β-O-4 structure were the major binding sites of lignin on the α-amylase molecule. Molecular docking studies indicated that the binding residue on α-amylase for lignin was not the same as for chloride ions, and the major binding force was hydrogen bonding. Furthermore, the docking results also showed the structural change of lignin induced by α-amylase. Thus, this work provided a new insight into the interaction between lignin from Canna edulis ker residues and α-amylase, which may be beneficial to apply lignin in the food industry.

Preparation and Oxidation Stability Evaluation of Tea Polyphenols‐Loaded Inverse Micro‐Emulsion

Compared to synthetic antioxidants, tea polyphenols (TPs) has its own advantages in edible oil industry, however, the hydrophilic properties have restricted its applications. In this study, the ternary phase diagram of TPs-loaded micro-emulsion (ME) system was constructed, in which glyceryl monooleate (GMO), Tween80, linoleic acid as the surfactants, ethanol as the co-surfactant and soybean, corn, sunflower oil as the oil phase, have been used for the preparation of ME. The results indicated that a composition of ME (57.5% oil, 18% Tween80, 18% GMO, 4% Linolic acid, and 2.5% water+ethanol) could dissolve maximum water and could stable for 2 mo at room temperature with an average diameter of 6 to 7 nm, as detected by means of dynamic light scattering (DLS). The loaded of TPs into ME led to an increase of particle size to 15 to 16 nm, due to increased polarity of the water phase. The antioxidant capacity of TPs in ME was characterized by the peroxide value (POV) method. The addition of 1% water phase with 0.1 g/mL TPs could retain the POV at low value for 30 d at accelerating temperature 50 °C. Meanwhile, comparing the three edible oil, ME with corn oil has lower conductivity and higher value of POV during the storage. This work provides an efficient and environmentally friendly approach for the preparation of TPs-loaded ME, which is beneficial to the application of TPs in edible oil.