Comparative effects of pectin and hydrolyzed pectin coating as pre-frying treatments on acrylamide formation in potato chips.

This study aimed to compare the effects of pectin and hydrolyzed pectin coating as pre-frying treatments on acrylamide content and quality characteristics of fried potato chips. The hydrolyzed pectin with molecular weight (Mw) of 8.81 ± 0.49 kDa was obtained through partial degradation of pectin (Mw: 747.57 ± 6.73 kDa) using pectinase. Results showed that both pectin and hydrolyzed pectin coating significantly inhibited acrylamide formation and inhibition rates exceeded 90 %. Hydrolyzed pectin had stronger inhibitory activity against acrylamide formation than pectin, especially when the concentration of hydrolyzed pectin was >2 %, its inhibitory rate exceeded 95 %. Compared to pectin coating, hydrolyzed pectin coating endow fried potato chips with smaller browning, higher crispness, less moisture but higher oil content. Overall, hydrolyzed pectin had better application prospects than pectin in inhibiting acrylamide formation of fried potato chips.

Heat treatment of galangin and kaempferol inhibits their benefits to improve barrier function in rat intestinal epithelial cells.

Flavonols are bioactive substances in plant foods. In this study, two flavonols galangin and kaempferol were heated at 100°C for 30 min prior to assessing their effects on barrier function of rat intestinal epithelial (IEC-6) cells. Both heated and unheated flavonols (2.5-20 µmol/L dosages) were nontoxic to the cells up to 48 h post-treatment, and could promote cell viability values to 102.2-141.2% of control. By treatment with 5 µmol/L flavonols for 24 and 48 h, the treated cells time-dependently showed better improved physical and biological barrier functions than the control cells without any flavonol treatment, including higher transepithelial electrical resistance and antibacterial effect but reduced paracellular permeability and bacterial translocation. The results from real-time PCR and western-blot assays indicated that the cells treated with heated and unheated flavonols of 5 µmol/L dosage had up-regulated mRNA (1.13-1.81 folds) and protein (1.15-5.11 folds) expression for zonula occluden-1, occludin, and claudin-1 that are vital to the tight junctions of the cells. Moreover, protein expression of RhoA and ROCK were down-regulated into 0.41-0.98 and 0.40-0.92 folds, respectively, demonstrating a Rho inactivation that led to enhanced cell barrier integrity via the RhoA/ROCK pathway. Overall, galangin was more active than kaempferol to perform three biofunctions like improving cell barrier function, up-regulating tight junctions protein expression, and down-regulating RhoA/ROCK expression. Moreover, the heated flavonols were less effective than the unheated counterparts to perform these biofunctions. It is concluded that this heat treatment of galangin and kaempferol could inhibit their benefits to improve barrier function of IEC-6 cells.

Barrier-promoting efficiency of two bioactive flavonols quercetin and myricetin on rat intestinal epithelial (IEC-6) cells via suppressing Rho activation.

Polyphenols are beneficial to human health because of their bio-activities. In this study, two flavonols quercetin and myricetin with or without heat treatment at 100 °C for 30 min were assessed for their barrier-promoting efficiency in rat intestinal epithelial (IEC-6) cells. The results indicated that the heated and unheated flavonols at dose levels of 2.5-20 µmol L-1 had a nontoxic effect on the cells treated for 24 and 48 h but enhanced the values of cell viability larger than 100% (especially at a dose level of 5 µmol L-1). Moreover, the cells exposed to these flavonols of 5 µmol L-1 for 24 and 48 h had improved barrier integrity compared to the control cells without any flavonol treatment, reflected by enhanced transepithelial electrical resistance and anti-bacterial effect but decreased paracellular permeability and bacterial translocation. Moreover, the results from both mRNA and protein expression verified 1.1-3.4 fold up-regulation of zonula occludens-1, occludin, and claudin-1 that are critical to tight junctions and barrier function of cells. Furthermore, the expression of other two proteins RhoA and ROCK in the treated cells was also down-regulated, demonstrating suppressed Rho activation and consequently barrier promotion via the RhoA/ROCK signaling pathway. Overall quercetin, due to its lower molecular polarity, mostly gave higher barrier-promoting efficiency than myricetin, while the heated flavonols were always less efficient than the unheated counterparts to promote barrier integrity of IEC-6 cells. It is thus highlighted that flavonols can provide barrier-promoting effects on intestinal epithelial cells with a promoting efficiency dependent on flavonol polarity; however, heat treatment especially excessive heat treatment of plant foods might lead to damaged flavonol activity.

Effect of Cu/Mn-Fortification on In Vitro Activities of the Peptic Hydrolysate of Bovine Lactoferrin against Human Gastric Cancer BGC-823 Cells.

Bovine lactoferrin hydrolysate (BLH) was prepared with pepsin, fortified with Cu2+ (Mn2+) 0.64 and 1.28 (0.28 and 0.56) mg/g protein, and then assessed for their activity against human gastric cancer BGC-823 cells. BLH and the four fortified BLH products dose- and time-dependently had growth inhibition on the cells in both short- and long-time experiments. These samples at dose level of 25 mg/mL could stop cell-cycle progression at the G0/G1-phase, damage mitochondrial membrane, and induce cell apoptosis. In total, the fortified BLH products had higher activities in the cells than BLH alone. Moreover, higher Cu/Mn fortification level brought higher effects, and Mn was more effective than Cu to increase these effects. In the treated cells, the apoptosis-related proteins such as Bad, Bax, p53, cytochrome c, caspase-3, and caspase-9 were up-regulated, while Bcl-2 was down-regulated. Caspase-3 activation was also evidenced using a caspase-3 inhibitor, z-VAD-fmk. Thus, Cu- and especially Mn-fortification of BLH brought health benefits such as increased anti-cancer activity in the BGC-823 cells via activating the apoptosis-related proteins to induce cell apoptosis.

Effect of the Plastein Reaction in Presence of Extrinsic Amino Acids on the Protective Activity of Casein Hydrolysate against Ethanol-Induced Damage in HHL-5 Cells.

Casein hydrolysates (CH) were prepared using papain and modified by the plastein reaction (CH-P) in the presence of extrinsic phenylalanine (CH-P-Phe) or tryptophan (CH-P-Trp). The in vitro protective activity of CH and its modified products against ethanol-induced damage in HHL-5 cells was investigated. The results showed that the modification by the plastein reaction reduced the amino group content of CH. However, the modification by the plastein reaction in the presence of extrinsic amino acids could enhance the antioxidant, proliferative, cell cycle arresting, and anti-apoptosis activity of CH. Biological activities of CH and its modified products in the HHL-5 cells varied depending on the hydrolysate concentration (1, 2, and 3 mg/mL) and treatment time (24, 48, and 72 h). Generally, higher biological activities were found after cell treatment with CH or its modified products at concentration of 2 mg/mL for 48 h compared to other treatments. In addition, CH modified in the presence of tryptophan (CH-P-Trp) showed higher biological activity than that modified in the presence of phenylalanine (CH-P-Phe). Based on the obtained results, it can be concluded that casein hydrolysates with enhanced biological activity and potential health benefits can be produced by papain and the plastein reaction with the incorporation of extrinsic amino acids.

Copper or Manganese Supplementation Endows the Peptic Hydrolysate from Bovine Lactoferrin with Enhanced Activity to Human Gastric Cancer AGS Cells.

A lactoferrin hydrolysate (LFH) was generated from bovine lactoferrin by pepsin, mixed with Cu2+ and Mn2+ at 0.64-1.28 and 0.28-0.56 mg/g protein, respectively; and then their in vitro effects on human gastric cancer AGS cells were assessed. With incubation times of 24 or 48 h, LFH and its Cu2+/Mn2+ mixtures at 10-30 mg/mL in dose-dependent manner inhibited cell growth; and more, these mixtures showed higher activities than LFH alone. Cell treatments of LFH and the mixtures (25 mg/mL) for 24 h could arrest cell cycle at G0/G1-phase, damage mitochondrial membrane integrity, and induce apoptosis, while the mixtures were also more powerful than LFH to exert these three effects. Higher Cu2+/Mn2+ supplementation level resulted in higher growth inhibition, cell cycle arrest, mitochondrial membrane potential disruption, and apoptosis induction; furthermore, Mn2+ was notable for its higher efficacy than Cu2+ to increase these four effects. Western-blot assay results revealed that four apoptosis-related proteins Bad, Bax, cytochrome c, and p53 were up-regulated, and both caspase-3 and caspase-9 also were cleaved and activated; moreover, two autophagy-related proteins LC3-II and cleaved Beclin-1 were down- and up-regulated, respectively. It is thus concluded that Cu2+ and especially Mn2+ could endow supplemented LFH with increased anti-cancer effects in AGS cells, with two proposed events as enhanced apoptosis induction (via activating apoptosis-related proteins) and autophagy inhibition (via activating autophagy-related proteins).

Comparative experiments of fibril formation from whey protein concentrate with homogeneous and secondary nuclei.

Two types of special structures, homogeneous and secondary nuclei, form during fibril formation. The structural and functional properties of amyloid fibrils in whey protein concentrate (WPC) with different ratios of added homogeneous nuclei to secondary nuclei were investigated. Thioflavin T fluorescence analysis and kinetic equations indicated that two types of nuclei could accelerate WPC fibrillation compared with WPC self-assembling into amyloid fibrils, thereby reducing the lag time and increasing the number of fibrils. However, there were considerable differences in the nucleation-inducing capability of WPC fibrillation between homogeneous and secondary nuclei. The number of fibrils formed by adding homogeneous nuclei was higher than that obtained with secondary nuclei, the increase in the Th T fluorescence intensity induced by homogeneous nuclei was 1.83-fold much than secondary nuclei. Meanwhile, secondary nuclei yielded a 2.71-fold faster aggregation rate of WPC than homogeneous nuclei, particularly during the first hour of thermal treatment (protein mass ratio of nuclei to WPC 1:1). The gelation time of WPC after secondary nuclei addition was shorter, from 10 h (WPC (2.0/6.5)) to 4 h (WPC + HN) to 2 h (WPC + SN); however, the gel microstructure of WPC after the addition of homogeneous nuclei was denser, yielding a preferred water holding capacity.

Gas sensitivity and sensing mechanism studies on Au-doped TiO2 nanotube arrays for detecting SF6 decomposed components.

The analysis to SF6 decomposed component gases is an efficient diagnostic approach to detect the partial discharge in gas-insulated switchgear (GIS) for the purpose of accessing the operating state of power equipment. This paper applied the Au-doped TiO2 nanotube array sensor (Au-TiO2 NTAs) to detect SF6 decomposed components. The electrochemical constant potential method was adopted in the Au-TiO2 NTAs' fabrication, and a series of experiments were conducted to test the characteristic SF6 decomposed gases for a thorough investigation of sensing performances. The sensing characteristic curves of intrinsic and Au-doped TiO2 NTAs were compared to study the mechanism of the gas sensing response. The results indicated that the doped Au could change the TiO2 nanotube arrays' performances of gas sensing selectivity in SF6 decomposed components, as well as reducing the working temperature of TiO2 NTAs.

A Pt-doped TiO2 nanotube arrays sensor for detecting SF6 decomposition products.

The detection of partial discharge and analysis of SF6 gas components in gas-insulated switchgear (GIS) is important for the diagnosis and operating state assessment of power equipment. The use of a Pt-doped TiO2 nanotube arrays sensor for detecting sulfur hexafluoride (SF6) decomposition products is proposed in this paper. The electrochemical pulse deposition method is employed to prepare the sensor array. The sensor's response to the main characteristic gaseous decomposition products of SF6 is evaluated. The gas sensing characteristic curves of the Pt-doped TiO2 nanotube sensor and intrinsic TiO2 nanotube arrays sensor are compared. The mechanism of the sensitive response is discussed. Test results showed that the Pt-doped nanoparticles not only change the gas sensing selectivity of the TiO2 nanotube arrays sensor with respect to the main characteristic SF6 decomposition products, but also reduce the operating temperature of the sensor.

[Isolation, identification and characterization of an atrazine degrading bacterium].

An atrazine-degrading bacterial strain named L-6 was isolated from the sludge mixture of the sewage treatment plant by cultivating in raw water with limited nutrition and aeration and was domesticated steadily using SBR (Sequencing Batch Reactor) for two months. The degradation rate of atrazine in inorganic liquid culture medium with atrazine as the sole source of nitrogen could reach 89.2% after 96 hours. The cells showed shape of long rod under scanning electron microscope. After extraction of genomic DNA and PCR amplification, the 16S rRNA gene sequences were used for homology analysis and construction of phylogenetic trees. The results suggested that the 16S rRNA gene sequence of L-6 had up to 99% homology with those of many strains of Pseudomonas strains in GenBank database. With physiological and biochemical reactions, the strain L-6 was identified as Pseudomonas sp. Carbon use test indicated that L-6 can utilize glucose, fructose and citric acid sodium as carbon sources, but could not use sucrose, lactose or starch. The optimum degradation conditions were optimized as following:temperature 30 degrees C, initial pH 7-9.