Ascorbic Acid Solution Research Articles

Influence of exogenous ascorbic acid and glutathione priming on mitochondrial structural and functional systems to alleviate aging damage in oat seeds

BackgroundLoss of vigor caused by seed aging adversely affects agricultural production under natural conditions. However, priming is an economical and effective method for improving the vigor of aged seeds. The objective of this study was to test the effectiveness of exogenous ascorbic acid (ASC) and glutathione (GSH) priming in the repairing of aged oat (Avena sativa) seeds, and to test the hypothesis that structural and functional systems in mitochondria were involved in this process.ResultsOat seeds were artificially aged for 20 days at 45 °C, and were primed with solutions (1 mmol L− 1) of ASC, GSH, or ASC + GSH at 20 °C for 0.5 h before or after their aging. Seed germination, antioxidant enzymes in the ASC-GSH cycle, cytochrome c oxidase (COX) and mitochondrial malate dehydrogenase (MDH) activities, and the mitochondrial ultrastructures of the embryonic root cells were markedly improved in aged oat seeds through post-priming with ASC, GSH, or ASC + GSH, while their malondialdehyde and H2O2 contents decreased significantly (P < 0.05).ConclusionOur results suggested that priming with ASC, GSH, or ASC + GSH after aging could effectively alleviate aging damage in oat seeds, and that the role of ASC was more effective than GSH, but positive effects of post-priming with ASC and GSH were not superior to post-priming with ASC in repairing aging damage of aged oat seeds. However, pre-priming with ASC, GSH, or ASC + GSH was not effective in oat seeds, suggesting that pre-priming with ASC, GSH, or ASC + GSH could not inhibit the occurrence of aging damage in oat seeds.

Exogenously-applied Salicylic Acid and Ascorbic Acid Modulate some Physiological Traits and Antioxidative Defense System in Zea mays L. Seedlings under Drought Stress

THIS WORK was undertaken to evaluate the effects of salicylic acid (SA) (0.0 and 0.5 mM) and ascorbic acid (AsA) (0.0 and 100 ppm) on enzymes activity, soluble sugars, and some physiological traits of maize seedlings (Zay mays L.) under drought stress using PEG-6000. In general, under drought conditions, significant reduction in plant biomass and photosynthetic pigments was detected. On the other hand, soluble sugars (glucose, fructose and sucrose), soluble proteins, antioxidant enzymes activity [catalase (CAT), ascrobate peroxidase (APOX) and superoxide dismutase (SOD)], glutathione (GSH), proline and malondialdehyde (MDA) contents were increased significantly under drought as compared to control. Shoots of tested plants were more affected by drought stress than roots. Seed presoaking in AsA or SA solutions resulted in massive increase in growth parameters, chlorophyll contents, osmoprotectants (soluble sugars, free amino acids and soluble proteins), antioxidant enzymes activity [ascrobate peroxidase (APOX) and superoxide dismutase (SOD)] and non-enzymatic antioxidants [carotenoids, and glutathione (GSH)] content as compared to control. Conversely, proline, catalase (CAT) and malondialdehyde (MDA) content were decreased significantly. The present study established that, both salicylic acid and ascorbic acid alleviate drought stress in maize plants which could attribute to the increased in osmotic solutes and antioxidative capacity of maize plants.

Sucrose syrup reuse during one‐ and multi‐stage osmotic dehydration of pineapple

AbstractMulti‐stage osmotic dehydration of pineapple with sucrose syrups in gradually increasing concentration was experimentally evaluated and compared to the single‐stage dehydration process. Also, osmotic solutions were reused for five osmotic dehydration cycles, without syrup reconditioning treatment. Single‐ and multi‐stage osmotic treatments were carried out for 2 hr at 40°C. Changes in pH, total acidity, and content of soluble solids, water, and ascorbic acid, in fruit and osmotic solutions, were analyzed. Water loss decreased with cycles of syrup reuse in one‐stage treatments and remained almost unchanged in multi‐stage treatments. Dry matter content of pineapple fruit during four‐stage osmotic dehydration cascade (40, 50, 55, and 60 °Bx) was increased respect to one‐stage dehydration at 40 and 60 °Bx. With regard to retention of syrup characteristics, multi‐stage dehydration reached a better performance as compared with the single‐stage dehydration and through the syrup reuse could become a more economical, environmentally friendly process.Practical applicationsOsmotic dehydration allows to reduce the fruit water content with energy saving and conservation of fruit characteristics, but also involves some negative aspects. Syrup management is usually the most important technological problem in the osmotic dehydration process on an industrial scale. Osmotic solution recycling could contribute to the solution of this problem. In this study, the effectiveness of pineapple osmotic dehydration in multi‐stage and single‐stage, with syrup reuse, were compared. The research show: (1) multi‐stage treatment was the most effective for the retention of syrup properties; (2) syrup reuse did not affect the dehydrated pineapple characteristics through multi‐stage dehydration. Thus, results indicated the proposed dehydration operation is of easy implementation, economically and environmentally friendly.

Initial Treatment, Sublimation Drying and Storage Time of Sweet Pepper Crisps. Physico-Chemical Quality − Part I

Abstract The paper presents the impact of the initial processing, cultivar, and storage time on the physico-chemical quality of freeze-dried crisps. Sweet pepper after initial washing and crushing was subjected to further four combinations of the initial processing. The first combination included freezing, the second one blanching in 98°C and 2-minutes time, the third one -dehydration in 2% solution of ascorbic acid and the fourth one -dehydration in 2% solution of sodium chloride. Both types of dehydration were carried out in 70°C for 20 minutes with a 1:4 participation of raw material to osmotic solution. Blanched and dehydrated raw materials were subjected to freezing in -18°C for 24 hours. After the completed process of freezing, the samples were moved to a freezer-drier and were dried by sublimation in -18°C and the reduced pressure of 63 Pa. Based on the research analyses a significant variability of physico-chemical properties of the obtained freeze-dried sweet pepper with regard to a cultivar, processing type and storage time were reported. Freeze-dried yellow sweet pepper was the most similar to the fresh raw material. It was dehydrated in the ascorbic acid solution. The storage time considerably influenced the reduction of the quality properties of sweet pepper crisps.

Initial Treatment, Sublimation Drying and Storage Time of Sweet Pepper Crisps. Microbiological Quality − Part II

Abstract The paper presents the impact of the initial processing, cultivar, and storage time on the physical and chemical quality of freeze-dried sweet pepper crisps. Sweet pepper after initial washing and crushing was subjected to further four combinations of the initial processing. The first combination included freezing, the second one blanching in 98°C and 2-minutes time, the third one -dehydration in 2% solution of ascorbic acid and the fourth one - dehydration in the 2% solution of sodium chlo-ride. Both types of dehydration were carried out in 70°C for 20 minutes with a 1:4 participation of raw material to osmotic solution. Blanched and dehydrated raw materials were subjected to freezing in -18°C for 24 hours. After the completed process of freezing, the samples were moved to a freezer-drier and were dried by sublimation in -18°C and the reduced pressure of 63 Pa. The research that was carried out proved that the microbiological quality of the obtained sweet pepper lyophilizes was significantly affected by the cultivar, treatment type and storage time. These factors significantly diversified the number of micro-organisms in sweet pepper crisps. No initial processing before sublimation drying caused a considerably average increase of the number of psychrophile and mesophilic bacteria in crisps from both sweet pepper cultivars. A considerable reduction of their total number took place during blanching and dehydration in the ascorbic acid solution and sodium chloride solution. Additionally, along with the storage time, reduction of the total number of psychrophilic, mesophilic bacteria, fungi and yeasts was reported.

Fast room temperature cloud point extraction procedure for spectrophotometric determination of phosphate in water samples

A novel fast room temperature cloud point extraction (RT-CPE) procedure for preconcentration and spectrophotometric determination of phosphate based on the heteropoly blue formation was developed. The proposed method includes the formation of yellow molybdoantymonatophosphoric heteropoly complex, its extraction into Triton X-100 micellar phase obtained at room temperature and reduction of heteropoly complex by ascorbic acid solution in ethanol and absorbance measurement of heteropoly blue at 790 nm. Under optimal conditions (1% (v/v) of Triton X-100 and 0.05 M of ammonium benzoate for initiating of RT-CPE; 0.13 M ethanolic solution of ascorbic acid for reduction of heteropoly complex and dilution of surfactant rich phase), the calibration graph is linear in the range of phosphate concentrations of 1.58–63 μg L−1. The proposed RT-CPE procedure has been successfully applied to preconcentration phosphates and its spectrophotometric determination in water samples.

Effect of Chemical Pretreatment on Drying Kinetics and Physio-chemical Characteristics of Yellow European Plums

ABSTRACT Drying of plums to prunes is an important postharvest processing step, as it results in a product with higher nutrient density, increased shelf life, and significantly greater antioxidant and fiber content. However, due to the waxy layer present on the plums surface having low permeability toward moisture, plum dries very slowly which is an energy-demanding process. Therefore, to breakdown waxy layer on the surface and enhancement of skin moisture diffusivity, two genotypes (V91074 and V95141) of Yellow European Plums (YEPs) were dipped in 1% (w/v) of Ascorbic Acid (AA), Citric Acid (CA), and Potassium Meta-bisulfite (KMS) solution for 1 min at 40°C. The pretreated YEPs were dried at three different temperatures (50°C, 60°C, and 70°C) until a final moisture content of approximately 30% (wet basis) was reached. It was observed that treated samples (AA and KMS) dried faster as compared to untreated samples, except for CA treatment where no significant difference in drying time was observed. One model cannot be selected for describing the thin layer drying characteristics of YEPs. Five out of 11 models used were found to be a perfect fit for genotype V91074 and genotype V95141, respectively. Pretreatment had a significant effect on effective moisture diffusivity (Deff). Deff for untreated and treated plum samples ranged between 4.6 × 10−11 to 8.6 × 10−11 (m2/s) and 4.9 × 10−11 to 9.1 × 10−11 (m2/s). The drying temperature had a significant effect on phenolic content and antioxidant activity, whereas no significant effect of pretreatment was observed.

Effects of Anti-browning Treatments on the Polyphenol Oxidase and Antioxidant Activity of Fresh-Cut Potatoes by Using Response Surface Methodology

Fresh-cut potatoes are a good option for consumers who want a healthy diet but have limited time to prepare meals. However, the polyphenol oxidase enzyme released during cutting of potatoes reacts with phenolic compounds, causing browning. Cold storage can slow down this reaction to some extent, but it cannot prevent it. Enzymatic browning lowers polyphenol content and reduces consumer appreciation of freshly cut potatoes stored in the refrigerator for later preparation of a meal. For this reason, studies to minimise negative changes in fresh-cut potatoes during cold storage are important. The quality of freshly cut potatoes immersed in ascorbic acid and collagen hydrolysate solutions was investigated to obtain maximum storage time by using response surface methodology. Colour, polyphenol oxidase (PPO) activity and antioxidant activity were monitored to estimate quantitative changes of the product over refrigerated storage. The binary effects of collagen hydrolysate and ascorbic acid slowed polyphenol oxidase activity and prevented browning of potato surface colour. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging effect increased with the use of collagen hydrolysate and ascorbic acid at the beginning of storage and decreased at the end of storage. ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) radical cation scavenging effect increased with the use of collagen and ascorbic acid during storage. The treatment of collagen hydrolysate and ascorbic acid in fresh-cut potatoes was successful in slowing PPO activity at the end of storage. Optimal conditions slowing down PPO activity at the end of storage are collagen 0.22% and ascorbic acid 0.30%.

Comparative analyses of three pretreatments on color of kiwifruits during hot air drying

Color is one of the most important quality attributes for agricultural products due to its great influence on consumers’ appetite. Effects of pretreatments, including blanching with hot water, osmosis with sucrose solution, and soaking with ascorbic acid solution on the color of kiwifruit slices were investigated during hot air drying, and three models (i.e. zero-order, first-order and Weibull models) were used to describe the color change kinetics of soaking samples. The results illustrated that color parameters (L*, a* and b*) of dried kiwifruit slices were improved significantly by immersing in sucrose solution or ascorbic acid solution before drying, whereas immersing in hot water for long time led to severe color deterioration. For un-pretreated samples, the Weibull model was the best to describe change kinetics of L* and a* values with R2 =0.974 and 0.996, respectively, while the zero-order model was best for the changes of ΔE value (R2 =0.996). For samples immersed in 1% ascorbic acid solution for 15 min, change kinetics of L* and ΔE values were best fitted to zero-order models with R2 =0.988 and 0.972, respectively. ΔE of dried samples without pretreatment was 12.55, but decreased by approximately 16.33% when samples soaked in 1% ascorbic acid solution for 15 min before drying. Keywords: color, computer vision system, kinetic model, ascorbic acid, sucrose DOI: 10.25165/j.ijabe.20201302.5489 Citation: Xu R Z, Zhou X, Wang S J. Comparative analyses of three pretreatments on color of kiwifruits during hot air drying. Int J Agric & Biol Eng, 2020; 13(2): 228–234.

Диэлектрлі беттерде антибактериалды мысқұрамды наноқабықшаларды алу

Activation of the surface of cotton fabrics before obtaining a chemical copper film is recommended to be carried out by precipitation of dispersed copper particles. For this purpose, physical and chemical processes occurring in thin layers of copper chloride solutions under the influence of the visible spectrum of electromagnetic solar radiation are used. In this case, copper chlorides interact with cellulose, which is the main component of the fabric, forming copper monochloride. It is shown that this interaction occurs from exposure to sunlight. After that, the fabric is moistened with a solution of ascorbic acid and again exposed to solar radiation. Electrons located in a semiconductor under the influence of solar photons receive additional energy and oxidize the copper element, and the free spaces that appear in this case are filled with electrons depending on the oxidation of ascorbic acid. As a result of these processes, a shell containing copper particles that can catalyze the chemical copper is formed on the surface of the tissue.

Dispersion of chitosan nanoparticles stable over a wide pH range by adsorption of polyglycerol monostearate

We have developed stable chitosan colloids over a wide pH range without cross-linkers or gelling agents. The colloid was prepared using chitosan nanoparticle obtained from pulverization of bulk chitosan powder, followed by surface treatment using small amount of ascorbic acid (AA) and polyglycerol monostearate (PGMS) in water. Chitosan nanoparticles were well dispersed in a diluted AA solution due to the protonation of the chitosan chain on the surface. And then, the addition of PGMS led them to exhibit highly stable dispersion even in alkali conditions and 50 °C. The hydrodynamic diameter of the colloid was monitored using dynamic light scattering and the real image of the colloid was obtained using cryo-electron microscope measurement. This chitosan colloid will be useful for developing food ingredients or drug carrier templates that should be stable over a wide pH range.

Structural, magnetic and dielectric studies of siderite nano-particles synthesized by hydrothermal method

Siderite or ferrous carbonate [Formula: see text] is a well-known mineral and finds applications in various fields such as dietary supplement to treat anemia and in petroleum drilling fluids for [Formula: see text] removal. The FeCO3 nano-particles are synthesized by hydrothermal method using aqueous solutions of iron sulfate, ascorbic acid and ammonium carbonate with a molar ratio of 1:1:3, respectively, and heating at [Formula: see text]C for 1.5 h in Teflon-lined stainless steel autoclave. The recovered sample is characterized by several techniques. The powder XRD indicates the hexagonal crystal system and the average crystallite size of 17.32 nm are obtained from the Scherrer’s formula and 18.98 nm is obtained from the Williamson and Hall formula. The TEM images suggest the spherical nature of the nano-particles. The EDX confirms the elemental presence of iron, carbon and oxygen. The impedance and dielectric studies are carried out within 20 Hz–2 MHz range at room temperature. The complex impedance plot, i.e. the Nyquist plot, is composed of one semicircle indicating the contribution from the grain only. The Jonscher’s power-law is applied to AC conductivity data. The VSM data at room temperature and at low temperature, i.e. 20–300 K range, suggests a weak antiferromagnetic nature of the sample.

Fabrication of tough, self‐recoverable, and electrically conductive hydrogels byin situreduction of poly(acrylic acid) grafted graphene oxide in polyacrylamide hydrogel matrix

ABSTRACTDeveloping electrically conductive hydrogels with good electronic properties and excellent mechanical performance is significant to their potential applications. In this article, we present a strategy to fabricate tough, self‐recoverable and electrically conductive hydrogels containing reduced graphene oxide (rGO). Poly(acrylic acid) grafted graphene oxide (GO‐g‐PAA) was synthesized and incorporated into chemically crosslinked polyacrylamide (PAM) networks to obtain GO‐g‐PAA/PAM hydrogels, which were further treated with ascorbic acid solution at ambient temperature to give rGO‐g‐PAA/PAM hydrogels. The interfacial interaction between GO/rGO and hydrogel matrix was improved by reversible hydrogen bonds between the grafted PAA chains and PAM matrix. Consequently, both GO‐g‐PAA/PAM and rGO‐g‐PAA/PAM hydrogels exhibited improved tensile properties, excellent energy dissipation, and rapid self‐recovery. Thein situchemical reduction of GO‐g‐PAA in hydrogel matrix endowed rGO‐g‐PAA/PAM hydrogels with satisfactory electrical conductivity and obvious resistance change upon stretching. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48781.

Predictive factors for inadequate bowel preparation using low-volume polyethylene glycol (PEG) plus ascorbic acid for an outpatient colonoscopy

Low-volume polyethylene glycol (PEG) plus ascorbic acid solutions are widely used for bowel cleansing before colonoscopy. This study aimed to investigate the pre-endoscopic predictive factors for inadequate preparation in subjects receiving low-volume PEG plus ascorbic acid. A prospective study was performed at Gangnam Severance Hospital, Korea, from June 2016 to December 2016. All participants received low-volume PEG plus ascorbic acid solutions for outpatient colonoscopy. The split-dose bowel preparation was administered in subject with morning colonoscopy while same day bowel preparation was used for afternoon colonoscopy. 715 patients were enrolled (mean age 56.1 years, 54.4% male), of which 138 (19.3%) had an inadequate bowel preparation. In multivariable analysis, cirrhosis (OR 4.943, 95% CI 1.191–20.515), low (less than 70%) compliance for three-day low-residual diet (OR 2.165, 95% CI 1.333–3.515), brown liquid rectal effluent (compared with clear or semi-clear effluent) (OR 7.604, 95% CI, 1.760–32.857), and longer time interval (≥2 hours) between last defecation and colonoscopic examination (OR 1.841, 95% CI, 1.190–2.849) were found as an independent predictors for inadequate preparation. These predictive factors may be useful in guiding additional intervention to improve quality of bowel preparation.

Preclinical pharmacokinetics of M10 after intragastrical administration of M10-H and M10-Na in Wistar rats

As a myricetin derivative, M10 is a potent agent of anti-chronic colonic inflammation. It has better activity than myricetin in preventing azoxymethane/dextran sulfate sodium - induced ulcerative colitis. Here, we introduce a sensitive quantification method based on ultra performance liquid chromatography-tandem mass spectrometry for the determination of M10-H and M10-Na in Wistar rat plasma. Samples were treated with L - ascorbic acid and phosphate buffer solution to maintain stability and with acetonitrile to remove the proteins in the plasma. The supernatant was separated with BEH C18 column and eluted with ultrapure water and acetonitrile both containing 0.1% formic acid. The detection was performed by a triple quadrupole mass spectrometer with positive electrospray ionization mode in multiple reactive monitoring. This method was validated for the carryover effect, selectivity, accuracy, precision, matrix effect, stability, and recovery. A linear correlation was established between concentration and response by the calibration curves over 10–2000 ng·mL−1 (r > 0.99). This method was applied to a pharmacokinetic study of intragastrical administration of M10-H and M10-Na in Wistar rats. In addition, the relative bioavailability of M10-H to M10-Na in Wistar rats was 60 ± 19%, calculated by the ratio of area under concentration (AUC) of M10-H to M10-Na after intragastrical administration of a single dose (100 mg·kg−1 for M10-H and M10-Na, respectively) in Wistar rats.

A rapid synthesis and antibacterial property of selenium nanoparticles using egg white lysozyme as a stabilizing agent

A simple method for the rapid synthesis of selenium nanoparticles (SeNPs) by the reduction of selenium dioxide using an aqueous egg white lysozyme solution (stabilizing agent) and ascorbic acid solution (reducing agent) has been described. The formation of SeNPs is assured by characterization with UV–Vis, FT-IR, XRD and morphological characters that were observed using TEM analyses. The absorbance of the SeNPs is found at 250 nm. The TEM images show that the SeNPs are uniform and in spherical shape of size 40–60 nm. The crystalline nature of SeNPs is assured by XRD analysis. The antibacterial property of synthesized SeNPs was tested against the pathogenic bacteria, i.e., Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus pneumoniae, Proteus mirabilis and Klebsiella pneumoniae. SeNPs showed more antibacterial activity against B. subtilis (19 mm) and Streptococcus pneumoniae (15 mm) as compared with commercially available antibiotics such as streptomycin and erythromycin. The SeNPs synthesized via this process has proficient antimicrobial activity against pathogenic bacteria. SeNPs could play a significant role in pharmaceutical industries for the development of efficient antibiotic agents.

Synthesis of cerium phosphate white pigments from cerium carbonate for cosmetics

Catalytically active cerium dioxide is used as light reflection materials for cosmetic applications. In fact, cosmetics containing this pigment cause too much oxidation on the skin. Therefore, the substitute for cerium dioxide is required to prepare the cosmetics without catalytic activity. Herein, as novel white pigments for use in cosmetics, cerium phosphates were prepared from cerium carbonate with hydrothermal treatment. The chemical composition (X-ray diffraction pattern and Infrared spectrum), powder properties (scanning electron microscopy images and particle size distributions), the photo and oxidation catalytic activity, color phase (ultraviolet-visible reflectance spectra and L*a*b* values), and smoothness of the cerium phosphates were evaluated. The photocatalytic activity of the samples was assessed from the decomposition of methylene blue. The oxidation catalytic activity of samples was estimated with ascorbic acid solution. All samples prepared in this work indicated X-ray diffraction pattern of cerium phosphate hydrate. Samples prepared in this work had no photo and oxidation catalytic activities. They indicated the absorption at 300–330 nm and high reflectance within the range of visible light. Because samples indicated higher L* values than 89, these materials are possible to use as white pigments. All materials prepared in this work had higher smoothness than cerium oxide.

Antioxidant Activity of Avicennia alba Blume, (1826) Family Avicenniaceae, Leaf Extracts Using DPPH Assay

The antioxidant activity of Avicennia alba Blume, (1826) leaf extract was determined using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) Free Radical Scavenging Activity Assay. Petroleum ether and 95 % ethanol were used as solvents in two separate macerations. Only the ethanolfree extract (TSB) exhibited antioxidant activity; it showed a color change from purple to light yellow similar to positive control (ascorbic acid solution) and a decrease in absorbance relative to negative control (95% ethanol). The results of the DPPH free radical scavenging activity assay was subjected to statistical analysis using one way ANOVA then post hoc analysis results of TSB showed no significant difference vs positive control, a percentage antioxidant activity of 68.24% ± 12.23 and 76.43% ± 9.22 respectively. The ethanol-free extract (TSB) underwent phytochemical screening by test tube method where it revealed the presence of saponins, tannins, flavonoids, and glycosides. It was then subjected to column chromatography for partial purification of its chemical compounds; fractions from the eulates were collected and were pooled according to their TLC profile specifically Rf values. The fractions that showed significant spots under UV light were fractions 1 and 2; and fractions 4 and 5. These two sets of fractions were tested to DPPH free radical scavenging assay. Both fractions showed similar color change as the positive control and a decrease in absorbance relative to the negative control. Fractions 1&amp;2 showed 69.97% ± 2.439 percentage antioxidant activity which had no significant difference to the positive control with the highest antioxidant activity of 87.88% ± 3.357 .The p-value (&lt;0.01) obtained manifested that there was significant difference between the test solutions with their antioxidant activity. After DPPH assay, the most active fractions 1 &amp; 2, were subjected to FT-IR and GC-MS. Infrared spectrum showed the presence of aliphatic C-H bonds, C=O bond, and –OH bonds while the GC-MS analysis revealed five compounds which were based on the molecular ion showed at m/z = 537.4. The functional groups present in the compounds from FT-IR and GC-MS analyses and the secondary metabolites present in phytochemical screening seemed to be responsible for the antioxidant activity of Avicennia alba leaf extracts.

Antioxidant Activity of Avicennia alba Blume, (1826) Family Avicenniaceae, Leaf Extracts Using DPPH Assay

The antioxidant activity of Avicennia alba Blume, (1826) leaf extract was determined using the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) Free Radical Scavenging Activity Assay. Petroleum ether and 95 % ethanol were used as solvents in two separate macerations. Only the ethanol-free extract (TSB) exhibited antioxidant activity; it showed a color change from purple to light yellow similar to the positive control (ascorbic acid solution) and a decrease in absorbance relative to the negative control (95% ethanol). The results of the DPPH free radical scavenging activity assay were subjected to statistical analysis using one-way ANOVA then post hoc analysis results of TSB showed no significant difference vs positive control, with a percentage antioxidant activity of 68.24% ± 12.23 and 76.43% ± 9.22 respectively. The ethanol-free extract (TSB) underwent phytochemical screening by test tube method which revealed the presence of saponins, tannins, flavonoids, and glycosides. It was then subjected to column chromatography for partial purification of its chemical compounds; fractions from the eulates were collected and pooled according to their TLC profile specifically Rf values. The fractions that showed significant spots under UV light were fractions 1 and 2, and fractions 4 and 5. These two sets of fractions were tested to DPPH free radical scavenging assay. Both fractions showed a similar color change to the positive control and a decrease in absorbance relative to the negative control. Fractions 1&amp;2 showed 69.97% ± 2.439 percentage antioxidant activity which had no significant difference from the positive control with the highest antioxidant activity of 87.88% ± 3.357. The p-value (&lt;0.01) obtained manifested that there was a significant difference between the test solutions with their antioxidant activity. After the DPPH assay, the most active fractions 1 &amp; 2, were subjected to FT-IR and GC-MS. The infrared spectrum showed the presence of aliphatic C-H bonds, C=O bonds, and –OH bonds while the GC-MS analysis revealed five compounds that were based on the molecular ion showed at m/z = 537.4. The functional groups present in the compounds from FT-IR and GC-MS analyses and the secondary metabolites present in phytochemical screening seemed to be responsible for the antioxidant activity of Avicennia alba leaf extracts.

Minimally Processed for Cassava Browning Inhibition by Ascorbic Acid and Oxygen Absorbent

The objective of this study was to examine the use of ascorbic acid and oxygen absorbent as anti browning agent for minimally processed cassava. The solution of 0% and 1% (w/v) ascorbic acid combined with packaging treatment by adding oxygen absorbent (+OA) and without oxygen absorbent (-OA) were use as anti browning system. Peeled cassava was dipped in the solutions for 30 minutes then packed into polyethylene plastic with packaging treatment and stored at 5°C. The results showed that dipping in 1% ascorbic acid solutions and oxygen absorbent packaging treatment could inhibit oxidation of polyphenol oxidase (PPO) of minimally processed cassava indicated by lower Browning Index.