Levels Of Sodium Hypochlorite Research Articles

Physicochemical and Morphological Properties of Litchi Seed Starch Oxidized by Different Levels of Sodium Hypochlorite

AbstractNon‐conventional starch sources have emerged as an interest due to their inherent physicochemical properties similar to conventional starches. This study aimed to enhance the value of non‐conventional litchi seed starch by employing anoxidizing process using different concentrations of sodium hypochlorite (NaOCl)(0.5, 1.5, 2.5, 3.5, 4.5%). The carbonyl and carboxyl content of oxidized starch was in the range of (0.019 – 0.323%) and (0.044 – 0.425%) showing an increase with the increasing concentration of NaOCl. The native and oxidized starches were further characterized for their functional and structural properties. The amylose content of native starch was 21.52% which was reduced to (19.34 – 13.43%) upon oxidation. The water and oil absorption capacities increased with theoxidation level. The swelling power(g/g) and solubility (g/100g) for native starch were 16.17 and 16.20 and 9.5 and 31.40 for modified starch. The oxidized starch produced clearer pastes. Scanning electron microscopy revealed surface erosion and cavities in oxidized starch granulesat higher concentrations. The oxidized starch showed higher relative crystallinity. FTIR was further used to assess structural changes in starches. Therefore, it can be concluded that oxidation significantly altered the characteristics of litchi seed starch, expanding its potential applications in various industries.

Stabilization of Pickering emulsions by oxidized starch/zein nanoparticle complexes

In this study, oxidized starch (OS)/zein nanoparticles (ZNP) complexes were prepared and used to stabilize Pickering emulsions. The effect of starch oxidation using three levels of sodium hypochlorite (2.0%, 3.0%, 4.0% active chlorine, dry basis) on the properties of OS/ZNP complexes and complex-stabilized Pickering emulsions were evaluated. The interaction between oxidized starch and zein nanoparticles was confirmed by X-ray diffractometry (XRD) and Fourier transform infrared (FT-IR) spectrometry. The presence of oxidized starch improved the wettability of OS/ZNP complexes. The optimum contact angle (θ) of OS/ZNP complexes was 90.88°, when starch was oxidized with 3.0% active chlorine (3.0% OS). The appearance, micromorphology and oil droplet-size distribution suggested that OS/ZNP complex-stabilized Pickering emulsions were formed. Rheological measurements indicated that Pickering emulsions showed shear-thinning behavior. Furthermore, the viscoelasticity of Pickering emulsions was dependent on the oxidized starch and oil fractions. Stability test showed that the stability of Pickering emulsion can be improved by increasing the oil fraction from 20% to 50%, and Pickering emulsion stabilized by 3.0% OS/ZNP complexes had the highest stability. This work provides information on OS/ZNP complex-stabilized Pickering emulsions.

Characterization and Antibacterial Properties of Autoclaved Carboxylated Wood Nanocellulose.

Cellulose nanofibrils (CNFs) were obtained by applying a chemical pretreatment consisting of autoclaving the pulp fibers in sodium hydroxide, combined with 2,2,6,6-tetramethylpiperidinyl-1-oxyl-mediated oxidation. Three levels of sodium hypochlorite were applied (2.5, 3.8, and 6.0 mmol/g) to obtain CNF qualities (CNF_2.5, CNF_3.8, and CNF_6.0) with varying content of carboxyl groups, that is, 1036, 1285, and 1593 μmol/g cellulose. The cytotoxicity and skin irritation potential (indirect tests) of the CNFs were determined according to standardized in vitro testing for medical devices. We here demonstrate that autoclaving (121 °C, 20 min), which was used to sterilize the gels, caused a modification of the CNF characteristics. This was confirmed by a reduction in the viscosity of the gels, a morphological change of the nanofibrils, by an increase of the ultraviolet-visible absorbance maxima at 250 nm, reduction of the absolute zeta potential, and by an increase in aldehyde content and reducing sugars after autoclaving. Fourier-transform infrared spectroscopy and wide-angle X-ray scattering complemented an extensive characterization of the CNF gels, before and after autoclaving. The antibacterial properties of autoclaved carboxylated CNFs were demonstrated in vitro (bacterial survival and swimming assays) on Pseudomonas aeruginosa and Staphylococcus aureus. Importantly, a mouse in vivo surgical-site infection model on S. aureus revealed that CNF_3.8 showed pronounced antibacterial effect and performed as good as the antiseptic Prontosan wound gel.

Properties of jackfruit seed starch oxidized with different levels of sodium hypochlorite

ABSTRACTThe effect of active chlorine concentrations (1–5%) on the properties of jackfruit seed starch was investigated. Both the carbonyl and carboxyl contents of the oxidized starches generally increased with progressive increases in the active chlorine concentration. No evidences of alteration in the morphology and X-ray diffraction pattern were observed after oxidation, while the decrease in relative crystallinity was found. The swelling power of the oxidized starch tended to decrease with the active chlorine levels, particularly at a low level of active chlorine (1–3%). No significant differences in the peak temperature (Tp) and the end temperature (Te) were found between the native and the oxidized starches, while the oxidized starches had lower onset temperatures (To). Parameters, such as pasting temperature, peak viscosity, and setback, decreased with the concentration of active chlorine. In addition, lower syneresis and turbidity were found in all oxidized starches during refrigerated storage compared to the native starch.

Partial Characterization of Tamarind (Tamarindus indica L.) Kernel Starch Oxidized at Different Levels of Sodium Hypochlorite

The effects of different levels of sodium hypochlorite (1–4 g/100 g dry solids active chlorine) on the physicochemical, pasting, and structural properties of tamarind kernel starches were investigated. The isolated starch had low traces of non-starch components, such as protein, fat, and ash, indicating its purity. Both the carboxyl and carbonyl contents in the oxidized starches increased significantly with the increase in chlorine concentration. The introduction of carboxyl and carbonyl groups resulted in significantly lower amylose content. The swelling power of oxidized starches was significantly lower than native starch and the solubility values increased when the chlorine concentration increased at all the measured temperatures. The percentage of light transmittance increased progressively after oxidation. Pasting properties showed that in treatments at high active chlorine concentrations, the peak viscosity decreased more drastically than in treatments at low chlorine concentration, indicating a greater degradation of starch. The morphology of the starches was not altered after oxidation. After oxidative treatment no change in the X-ray diffraction pattern was observed but intensity of the peaks increased. Therefore, tamarind kernel being underutilized raw material, has a great potential as a non-conventional source of starch and desirable properties of this starch can be enhanced by oxidation for applications in food industry.

The influence of ultrasound on the degree of oxidation of hypochlorite-oxidized corn starch

Oxidized corn starch was prepared with and without sonication at different levels of sodium hypochlorite (0–2 g active chlorine/50 g starch) and treatment time (15 and 30 min). Gel permeation chromatography revealed that weight average molecular weight decreased while polydispersity index increased with increase in active chlorine concentration and treatment time. It was found that carbonyl and carboxyl contents, and swelling power of oxidized corn starch generally increased with progressive increase in active chlorine level, treatment time and in the presence of sonication. A reversed trend was observed for the solubility. Peak viscosity was found to decrease with increase in active chlorine concentration to a threshold level of 1 g active chlorine/50 g starch, after which peak viscosity increased as the active chlorine level was increased. Breakdown values and final viscosities were increased and decreased respectively with progressive increase in active chlorine concentration. These phenomena became significant as the starch was subjected to sonication and longer treatment time.

Clospore: A Liquid Medium for Producing High Titers of Semi-purified Spores of Clostridium difficile

Clostridium difficile continues to cause infections in healthcare and other settings. Its spores survive well indoors and require sporicidal chemicals for infection control. However, proper testing of disinfectants is impeded due to difficulties in obtaining viable spores of high enough quality and titers to meet current regulations for sporicidal claims. A new liquid medium (Clospore) has been developed, based on a systematic review of the compositions of 20 other available media. C. difficile spores grown in the new medium and treated with a mixture of lysozyme and trypsin yielded final suspensions with > 10(9) CFU/mL of viable spores, with a purity of > 91% as tested by spore-staining and phase-contrast microscopy. The spores showed a biological decay rate of about 0.1 log10/month when dried on metal disks and stored indoors (air temperature 23 +/- 2 degrees C; relative humidity 52.76 +/- 15.08%). Heating the purified spore suspensions to 70 degrees C for 10 min to inactivate any vegetative cells showed no spore activation or inactivation. The spores could be stored for at least 14 months either refrigerated (4 degrees C) or frozen (-20 or -80 degrees C) in 50% (v/v) ethanol with virtually no loss in viability. The resistance of the enzyme-treated spores to three levels of sodium hypochlorite (1000, 3000, and 5000 ppm), using a standardized quantitative carrier test, was almost identical to that of the spores concentrated by centrifugation alone. The described procedure has been successfully applied to four standard (ATCC) and six clinical strains of C. difficile.

Physico–chemical, morphological, and pasting properties of Pine nut (Araucaria angustifolia) starch oxidized with different levels of sodium hypochlorite

AbstractThe objective of this work was to study the effect of process temperature and active chlorine concentration on the main properties of Pine nut starch (PN). Samples of PN were oxidized with sodium hypochlorite at concentrations varying from 0.5 to 4.0 g active chlorine/100 g starch, at temperatures varying from 20 to 45°C according to a central composite rotational design, analyzing the results using response surface methodology. The concentration of active chlorine had an effect on the WSI, the quantity of carboxyl and carbonyl groups, the AM content and the percentage of light transmittance (650 nm) of the PN. The effect of temperature was observed on the water solubility index, the quantity of carbonyl groups and the percentage of light transmittance (650 nm) of the PN. Oxidation was more intense in the starch treated with 3.5% active chlorine.

Pathological effects of sodium hypochlorite administration through drinking water in male Japanese quails (Coturnix japonica)

Fifty male Japanese quails of 40 days of age were divided into five equal groups viz. A, B, C, D, and E. Drinking water supplemented with sodium hypochlorite at dose level of 0, 25, 50, 200, and 400 mg chlorine/L, respectively was offered for 6 weeks. At the end of week 6 when no clinical signs of toxicity of sodium hypochlorite appeared, the birds in groups B and C were shifted to 100 mg chlorine/L drinking water, and this level was increased fourfold (400, 1600, 6400 mg chlorine/L drinking water) every week, till i.e., 10th week (70 day). Afterwards all the birds were killed. Depression and anorexia were prominent clinical signs observed. Reduction in feed intake, body weight, and hematological parameters appeared in a dose-dependant manner. Decreased serum total proteins and weights of liver, heart, and kidneys were recorded in birds receiving high levels of sodium hypochlorite. Intoxicated birds were emaciated. Decreased weight and volume of the testes were observed in birds receiving high levels of sodium hypochlorite. However, birds receiving 400 mg chlorine (group E) had smaller but functional testes. Birds receiving higher level of chlorine (groups B and C) had decreased weight and volume of testes, atrophied seminiferous tubules, and arrested spermatogenesis. It was concluded that sodium hypochlorite at high levels, that is, 6400 mg/L in drinking water is toxic to the quails; therefore, it should be used with caution in poultry farming as drinking water disinfectant.

Partial characterization of banana starches oxidized by different levels of sodium hypochlorite

Chemical, physical, physicochemical and functional properties of oxidized banana starch by different levels of sodium hypochlorite (0.25–2.0% active chlorine) were studied. The content of carboxyl and carbonyl groups in the oxidized starches increased when chlorine concentration increased, however the level of carboxyl groups was higher than carbonyl groups because carbonyl groups were formed during the reaction were transformed to carboxyl groups. The L* factor was used to characterize the whiteness of the oxidized starches. When chlorine concentration increased the whitness increased too, but at the highest chlorine concentration the L* values were not different ( α=0.05). The oxidation carried out with a chlorine concentration between 0.25 and 1.0% produced starches with a viscosity peak higher than its native counterpart, however when the active chlorine concentration increased (1.25–2.0%) an inverse pattern was obtained; high chlorine concentration cleaved the starch chains and the peak viscosity decreased. The gelatinization temperature ( T p) of oxidized starches was higher than its native counterpart, but at the highest active chlorine concentration a decreased in the T p value was obtained. The enthalpy values of the oxidized starches were lower than the native starch and in general those values decreased when active chlorine concentration increased. These results agree with those obtained from viscoamylography since starch degradation is carried out with high chlorine concentration. The swelling power of the oxidized starches measured at low temperatures was lower than its native counterpart and the water solubility index increased when temperature and chlorine concentration increased.

Physicochemical properties of common and waxy corn starches oxidized by different levels of sodium hypochlorite

Physicochemical properties of common and waxy corn starches oxidized by different levels of sodium hypochlorite

Physicochemical properties of common and waxy corn starches oxidized by different levels of sodium hypochlorite

Structure and physicochemical properties of oxidized common and waxy corn starches by different levels of sodium hypochlorite (0.25–3.0% active chlorine based on dry starch weight) were studied. The oxidized common corn starch generally had a higher carboxyl content but a similar carbonyl content compared with the oxidized waxy corn starch. The introduction of carboxyl and carbonyl groups promoted starch hydration and swelling. The gelatinization temperature of the oxidized starches increased but the enthalpy remained unchanged. Oxidation at low concentrations of chlorine (≤1.0%) produced starch with significantly higher peak and final viscosities and less breakdown as measured by Micro Viscoamylography. The carboxyl groups formed hemiacetal crosslinks that strengthened the starch integrity. However, as more amylose and amylopectin were degraded at higher oxidation levels, the depolymerization of starch molecules overrode the effects of crosslinking. Both amylose and amylopectin were oxidized and degraded during oxidation but amylose was more susceptible to oxidation.

Establishment of Tetranychid Mites in vitro

Procedures were developed to determine if live, adult two-spotted spidermites (Tetranychus urticae Koch) could be surface disinfested before being introduced into in vitro cultures of torenia (Torenia fournieri L.). Three time periods (5, 10, and 15 minutes) and five levels of sodium hypochlorite (0.05% to 0.25%) were evaluated. Surface disinfestation was accomplished by agitating 2 × 3 cm pieces of infested bean leaves in sodium hypochlorite solutions and then drying in a mite drier apparatus. All sodium hypochlorite concentrations disinfested the mites completely, however high concentration levels were lethal to the mites. Exposure periods of 10 and 15 minutes also significantly increased mortality. For optimum disinfestation of two-spotted spidermites with minimum mortality, a concentration of 0.05% sodium hypochlorite and 0.05% Tween-20 for 5 minutes should be used.