Different Concentrations Of Citric Acid Research Articles

Ensuring Photocatalyst Properties on Cellulosic Fabric by Using Citric Acid Modified with TiO2 Degussa P25 Nanoparticles

Citric acid, which is a type of polycarboxylic acid, is environmentally friendly, and non-harmful and it can be used as a cross-linker. Titanium dioxide (TiO2) nanoparticle is a catalyst that provides many properties for textile products with its large surface area. Present study, a mixture was prepared with different concentrations of citric acid and commercial TiO2 Degussa P25 nanopowder suspensions. Two different curing temperatures (120°C and 140°C) were applied to the cotton fabrics in the pad-dry-cure method. The adhesion of the chemicals to the fiber surface was confirmed by scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometer (FT/IR) analysis. The yellowing effect caused by citric acid on cotton fabrics was eliminated with white TiO2 nanoparticles. Methylene blue was used for staining the samples. Color analyses were performed with a spectrophotometer to determine photocatalytic properties of the samples. It was determined that the samples treated with a mixture of 30 g/L citric acid and TiO2 suspensions were the most discolored samples after exposure to solar light. The photocatalyst properties of the samples were further improved by removing the aggregation of TiO2 NPs on the fiber surface with the washing procedure.

Effect of Particle Size and Citric Acid Concentration on the Yield and pH of Butterfly Flower (Clitoria ternatea L.) Extract

This research aimed to determine the effect of differences in butterfly pea flower particle size and citric acid concentration on butterfly pea flower extraction, including yield and pH value analysis. The results showed that the particle size of butterfly pea flowers and the concentration of citric acid affected the yield. pH analysis showed that only treatments with different concentrations of citric acid affected the pH of butterfly pea flower extract. The highest yield in the treatment (7.52) and the highest pH (4,74). The above treatment can only be used for acidic food products, and citric acid can be replaced with food additives that lower the pH value but do not affect the taste so that it can be applied to all types of food.

Photodegradation stability of huminated European pine (Pinus sylvestris L.) microveneers

Abstract Humins are heterogeneous and polydisperse furanic macromolecules derived from sugar biorefinery. Improving wood properties by humination has become of interest recently. This study examined the photodegradation stability of European pine sapwood microveneers modified with humins at different concentrations of citric acid (CA) and succinic acid (SA) as reaction catalysts, e.g., 1.5 %, 3 %, and 4.5 % wt.%. The photostability of huminated wood was assessed after 48 h, 96 h, and 144 h of exposure to the accelerated weathering test by means of mass loss and finite-span tensile strength. The results were compared with unmodified and also unweathered samples. The FT-IR spectroscopy showed apparent changes in the chemical structure of wood by humination modifications. The weight percentage gains of the samples increased with increasing the concentration of the catalyst. While no differences were observed between the samples after two weeks of the water leaching. The strength losses of weathered microveneers were, however, mostly reduced by humin-based formulas containing catalysts, where the microveneers modified with 1.5 % and 3 % CA showed respectively 32 % and 41 % lower strength loss values than the unmodified samples after 144 h of weathering. Overall, the results showed a high potential for humins to protect wood against photodegradation.

Application of sodium alginate-based edible coating with citric acid to improve the safety and quality of fresh-cut melon (Cucumis melo L.) during cold storage.

The safety and quality of fresh-cut melons is reduced by a series of decay processes by enzymatic browning and microbial contamination. This study aimed to assess the impact of a 2% sodium alginate-based edible coating (ALC) combined with different concentrations of citric acid (CA; 0.5%, 1%, 2%, and 3%) on the microbial safety and physical quality of fresh-cut melons during a 7-day storage period at 10°C. The findings revealed that the combination of ALC and 3% CA was successful in preventing the growth of pathogenic bacteria (Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus) and natural microflora on fresh-cut melons during storage. In addition, treating fresh-cut melons with ALC containing 3% CA improved their quality by reducing browning and softening during storage at 10°C. Based on these findings, it can be concluded that using ALC with 3% CA is an effective method to improve the safety and quality of fresh-cut melons.

Carbon dots on LAPONITE® hybrid nanocomposites: solid-state emission and inter-aggregate energy transfer.

This study delves into the photoluminescent characteristics of solid-state hybrid carbon dots/LAPONITE® (CDLP). These hybrid materials were synthesized using the hydrothermal method with a precise pH control set at 8.5. The LAPONITE® structure remains intact without structural collapse, and we detected the possible deposition of carbon dots (CDs) aggregates on the clay mineral's edges. The use of different concentrations of citric acid (10-, 6-, 2- and 1-times weight/weight of LAPONITE® mass, maintaining the 1 : 1 molar ratio with ethylenediamine) during synthesis results in different CDs concentrations in CDLP-A (low precursors concentration) and CDLP-D (high concentration) with an amorphous structure and average size around 2.8-3.0 nm. The CDLP displayed visible photoluminescence emission in aqueous and powder, which the last underwent quenching according to lifetimes and quantum yield measurements. Low-temperature measurements revealed an enhancement of the non-radiative pathways induced by aggregation. Energy transfer modelling based on Förster-Dexter suggests an approximate mean distance of 9.5 nm between clusters of CDs.

Crosslinked hydrogel loaded with chitosan-supported iron oxide and silver nanoparticles as burn wound dressing

Burns can result in infection, disability, psychosocial and economic issues. Advanced wound dressings like hydrogel absorb exudate and maintain moisture. Considering the antimicrobial properties of silver nanoparticles and iron oxide nanoparticles, the efficiency of cross-linked hydrogel loaded with chitosan-supported iron oxide and silver nanoparticles for burn wounds repair was investigated in animal model. Cellulose hydrogel dressing made from carboxymethylcellulose and hydroxyethylcellulose crosslinked with different concentrations of citric acid (10, 15, 20, and 30%) was produced. The physicochemical characteristics of the synthetized hydrogels including Fourier-Transform Infrared spectroscopy, Thermal behavior, Swelling properties, and Scanning Electron Microscope (SEM) were evaluated. The silver nanoparticles and iron nanoparticles were produced and the characteristics, cytotoxicity, antimicrobial activities and their synergistic effect were investigated. After adding nanoparticles to hydrogels, the effects of the prepared wound dressings were investigated in a 14-day animal model of burn wound. The results showed that the mixture comprising 12.5 ppm AgNps, and IONPs at a concentration ≤100 ppm was non-cytotoxic. Moreover, the formulations with 20% CA had a swelling ratio of almost 250, 340, and 500 g/g at pHs of 5, 6.2, and 7.4 after one hour, which are lower than those of formulations with 5 and 10% CA. The total mass loss (59.31%) and the exothermic degradation happened in the range of 273–335 °C and its T m was observed at 318.52 °C for hydrogels with 20% CA. Thus, the dressing comprising 20% CA which was loaded with 12.5 ppm silver nanoparticles (AgNPs) and 100 ppm iron oxide nanoparticles (IONPs) indicated better physicochemical, microbial and non-cytotoxic characteristics, and accelerated the process of wound healing after 14 days. It was concluded that the crosslinked hydrogel loaded with 12.5 ppm AgNPs and 100 ppm IONPs possesses great wound healing activity and could be regarded as an effective topical burn wound healing treatment.

Control of Fluoride Pollution in Cemented Phosphogypsum Backfill by Citric Acid Pretreatment.

Using phosphogypsum (PG) as the aggregate of cemented backfill is an economical and effective method of PG utilization. However, the stability and performance of cemented backfill are challenged by the rich fluoride content in PG. In this study, the effects of citric acid pretreatment on PG defluorination, backfill performance and environmental behavior were investigated by washing PG with different concentrations of citric acid and washing times. The results showed that the citric acid pretreatment could significantly reduce the fluoride content in PG and promote the hydration reaction with the binder, thus greatly reducing the usage and cost of the binder in actual production. Considering the efficiency of defluorination, the optimal citric acid concentration and washing times were determined to be 4% and 7-8 times, respectively. In addition, after citric acid pretreatment, the viscosity and setting time of the backfill slurry and the porosity of the backfill reduced, and the strength of the backfill improved, which was conducive to slurry pipeline transportation and underground mine stability. Finally, a further analysis of environmental behavior was conducted and it was found that the citric acid washing greatly reduced the content of fluoride in the bleeding water of slurry and the backfill leachate, which met the integrated wastewater discharge standard in China. The results of this study can provide important guidance for the large-scale recycling and environmental management of PG.

Facile auto combustion synthesis of CuO nanoparticles and their structure-opto-dielectric and photodetection performances: An effect of different citric acid concentrations

Copper oxide (CuO) belongs to the p-type semiconductors family and have several applications in various fields like solar cell, supercapacitor, dielectrics, data storage, biomedical, optoelectronics, etc. Hence, in the current work, we have prepared the nanoparticles (NPs) of CuO by flash combustion route using different concentrations of citric acid (CA). XRD analysis confirms the phase of the synthesized CuO NPs. A vibrational study also approves the synthesis of NPs of CuO. A systematic reduction in peak intensities and increase of FWHM was noticed in XRD and FT-Raman patterns, which indicates the size reduction with increasing the CA concentrations in CuO. The particle size determined by the W-H plot was observed to be reduced from 25 to 19 nm. SEM analysis confirms the morphology and approximate size of the prepared NPs. The CA concentrations enhanced the energy gap from 2.5 eV to 2.9 eV. The dielectric study shows the enhancement in dielectric constant with CA concentrations/size reduction, and its value lies between 95 and 110. The AC electrical conductivity also improved with CA concentration and frequency. The increasing concentrations of CA fuel led to a decreased photocurrent, and the γ values for 1 g and 3 g CA added CuO NPs based photodetector were obtained ∼ 0. 77 and 0.95. This means that at higher CA concentrations, the size is reduced, resulting in the reduction of traps in the device. Also, the photosensitivity of CuO has been improved with light intensity; however, it was found to be lower for 3 g CA-added CuO compared to 1 g CA-added CuO NPs-based photodetectors. Results indicate that the prepared NPs are of tremendous application in optoelectronic devices.

Effects of Slice Thickness and Pre-Treatment Concentration on the Quality Characteristics of Solar Dried Pineapple

The overall goal of this study was to determine the quality changes (vitamin C retention, browning, rehydration ratio) that occur during solar drying of pineapple as influenced by different processing conditions (slice thickness and pre-treatment concentration). Pineapple fruits were sliced to varying thicknesses (5 and 10 mm), pre-treated at different concentrations of citric acid (2, 5, and 10 g/l), and dried for 2 days in a Hohenheim model type solar tunnel dryer until a safe moisture level about ≤15% was reached. Samples were analyzed for changes in quality characteristics using standard AOAC methods. Dried pineapple slices were found to differ significantly in terms of browning scores and vitamin C retention (p≤0.05) while no differences were observed in the rehydration ratio (p>0.05). Slice thickness and pre-treatment concentration were observed to have a significant interaction effect on the browning score/index of pineapple slices during drying (p≤0.05). Overall vitamin C concentration increased for samples during the drying process with the maximum vitamin C concentration being 36.85 mg/100 g recorded in 5mm thickness samples pre-treated with 5% citric acid solution. Maximum vitamin C retention was recorded in samples sliced to 5mm thickness and pre-treated with 5 g/l citric acid solution (15.68) while minimum vitamin C retention (2.41) was recorded in 5mm slices treated with a 10 g/l citric acid solution. Rehydration ratio ranged from 1.60 to 2.53. There was no significant difference between the rehydration ratio between the different treatments at P≤0.05. The lowest browning index was observed in samples sliced to 10 mm thickness and treated at 5 g/l while the highest browning index was observed in samples sliced to 5mm and treated at 5 g/l of citric acid. The best-optimized conditions obtained for the given criteria were 5 mm slice thickness and 2 g/l pre-treatment concentration based on a maximum desirability of 0.639. For the optimized combination of drying parameters, the vitamin C content, the rehydration ratio, and the browning were 9.14, 2.43 and 0.47, respectively.

Effect of Citric Acid Modification on Physio‐Chemical, Structural, Rheological, Thermal Properties, and In Vitro Digestibility of Amaranthus paniculatus (Rajgeera) Starch

AbstractIn this study, starch is treated with different concentrations of citric acid (CA, 5, 10, 20, and 30 g/100 g dry basis) which leads to the production of citrate starch. The effect of CA concentration on physio‐chemical, structural, rheological, thermal properties, and digestibility is analyzed. A Fourier transform infrared (FTIR) spectroscopy Stands for FTIR peak at 1728 cm−1 is observed, indicating ester bond formation between CA and starch molecules. A nonsignificant change in the crystalline pattern is observed between native and citrate starch, whereas a decrease in relative crystallinity from 15.75% to 6.91% is observed. With the increase in the degree of substitution, gelatinization decreases, and gelatinization's enthalpy (ΔH) decreases from 13.72 to 9.63 J g−1. The rapid digestible starch (RDS) decreases by CA treatment, whereas slow digestible starch (SDS) and resistant starch (RS) increase significantly from 32.81 g/100 g dry basis to 39.45 g/100 g dry basis and 9.87 g/100 g dry basis to 25.26 g/100 g dry basis, respectively.

Characterization of citric acid crosslinked chitosan/gelatin composite film with enterocin CHQS and red cabbage pigment

A chitosan/gelatin composite packaging film with antioxidant activity, bacteriostatic activity and pH responsiveness was prepared. Red cabbage pigment (RC) and enterocin CHQS were added as actives. In addition, different concentrations of citric acid (CA) were selected as crosslinking agents. Before that, in order to improve the yield of enterocin CHQS and simplify the purification process, we cloned and expressed CHQS in E. coli BL21 (DE3), resulting in an approximately 10-fold increase in yield. The appearances of the films were uniform and transparent with some UV-blocking ability. The results of antioxidant experiments of the films showed that the antioxidant capacity of the films was significantly increased by the addition of RC. Ammonia sensitivity experiments showed that the films could respond to volatile ammonia. Cross-linking improved the thermal stability, water sensitivity and photosensitivity of the films. FTIR and XPS revealed the mode of interaction between CHQS, CA, RC and the composite film structure. FTIR, XPS and XRD confirmed the cross-linking effect of CA. Atomic force microscopy showed that the addition of CA significantly increased the roughness of the film surface. The release experiments of RC showed that the cross-linking of CA promoted the release of active substances from the film and avoided the excessive release due to the dissolution breakage of the film. In addition, bacteria inhibition experiments showed that the addition of CA increased the antimicrobial properties of the films The experiments demonstrated that CHQS was effectively released and the bacteriocins in the films were stably preserved. • Citric acid crosslinking improved smart packaging film properties. • Enterocin CHQS and red cabbage were added as active ingredients. • The water resistance of films containing citric acid improved significantly. • Enterocin CHQS might be kept stably in the films and released effectively.

Effect of Citric Acid Cross Linking on the Mechanical, Rheological and Barrier Properties of Chitosan.

In this study, acetic acid (AA-2% w/v), a combination of acetic acid and citric acid (AA-1% w/v + CA-1% w/w), and three different concentrations of citric acid (CA-2, 4 and 6% w/w) were used to create chitosan solution. The FTIR analysis showed the presence of residual CA in all the CA-containing samples where no trace of AA was observed. The tensile strengths of the CA-containing samples were lower than the AA samples. Whereas the values for the elongation at break of the CA samples were higher than the AA samples, which kept increasing with an increasing CA content due to the plasticizing effect from residual citric acid. The elongation at break values for 4 and 6% CA-containing samples were 98% higher than the AA samples. The samples prepared with CA showed shorter LVE regions that reduced with an increasing CA concentration compared to the AA samples. Different acid concentrations did not have a large effect on the gelation time. However, CA-containing samples showed higher viscosities as compared to the AA-containing solution, which increased with an increasing CA content. The water vapour transmission rates of the CA-containing samples were lower than the others. All the chitosan solutions suppressed the growth of the two test strains, and none of the variants reached an abs 600 nm at 0.2.

REINFORCED PECTIN-DES BIOPLASTIC WITH DIFFERENT CONCENTRATION OF CITRIC ACID

The constant demand for synthetic plastics has led to the accumulation of plastic waste in nature due to its non-biodegradable attributes. In this study, the properties of pectin as biodegradable bioplastic were enhanced using Deep Eutectic Solvent (DES) as a plasticiser with concentrations of citric acid as a crosslinker that was ranged from 1% to 4%. The physical characteristic and mechanical properties of bioplastics were determined using the thickness test and the tensile test. The sample with 3% citric acid showed the highest thickness value (0.25±0.01 mm). The results showed that the increase in the concentration of citric acid increased the film’s flexibility, thereby influencing the properties of the bioplastic film obtained. The highest citric acid concentration at 4% showed the highest flexibility with 29.02±2.99 MPa, 2.73±0.38% and 10.14±0.88 MPa for tensile strain, tensile stress and Young’s Modulus values, respectively. The presence of peak OH, C=O and C-O from Fourier Transform Infrared (FT-IR) spectroscopy outlined the formation and showed the interactions between the pectin, DES and citric acid in the bioplastic that was produced. In conclusion, the properties of bioplastic/pectin/DES were altered with the different concentrations of citric acid either as a crosslinker or as a plasticiser to become a new green alternative to synthetic plastics.

Synthesis and detailed characterization of sustainable starch‐based bioplastic

AbstractThere is an urgent requirement of replacing the environmentally hazardous petroleum‐based plastics with sustainable and efficient starch‐based bioplastics. Development and detailed characterization of the biodegradable bioplastics from plant‐based polysaccharides such as starch is essential to reduce plastic pollution in the environment. In this research, bioplastics were developed from an equivalent blend of starch from two different sources namely rice and potato (1:1, w/w), crosslinked with different concentrations of citric acid (CA). The effect of CA cross‐linking of starch‐based bioplastics was investigated on its physicochemical and functional properties. The X‐ray diffraction (XRD) spectra revealed that the synthesized bioplastics were amorphous in nature with broad diffraction peaks. Further, the peak at 1716 cm−1 in Fourier transform infrared (FTIR) spectra indicated the formation of ester bonds in CA cross‐linked bioplastics. Atomic force microscopy (AFM) revealed the surface roughness of the bioplastics decreased with increasing concentration of CA. Mechanical and thermal properties of bioplastics were characterized using universal testing machine, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), respectively.

A pH-responsive, biocompatible, and non-toxic citric acid cross-linked polysaccharide-based hydrogel from Salvia spinosa L. offering zero-order drug release

Salvia spinosa seeds hydrogel (SSH) was chemically cross-linked with four different concentrations of citric acid (CA), i.e., 1.25%, 2.5%, 5.0%, and 10.0%. The fabrication of CA cross-linked SSH (CA-cl-SSH) was confirmed through Fourier transform infrared spectroscopic analyses. The CA-cl-SSH appeared thermally as stable as SSH. The CA-cl-SSH was found pH-sensitive and exhibited maximum swelling in deionized water (DW) as compared to the buffers of pH 1.2, 6.8, and 7.4 following the order pH 1.2 < pH 6.8 < pH 7.4 < DW. Stimuli-responsive swelling and deswelling (on-off switching) behavior of CA-cl-SSH (2.5% CA) was found reversible at pH 7.4 and 1.2, in DW and normal saline, and DW and ethanol. CA-cl-SSH sustained the release of aceclofenac following the zero-order kinetics and non-Fickian diffusion mechanism. The in vivo radiographic images revealed the presence of CA-cl–SSH–based tablet formulation in GIT for 9 h. Hemocompatibility studies confirmed the non-thrombogenic and non-hemolytic potential of CA-cl-SSH. Acute oral toxicity study presented its safety profile owing to the absence of any mortality and toxic effects. Therefore, it can be concluded that CA-cl-SSH is a novel stimuli-responsive, biocompatible, and non-toxic polysaccharide-based biomaterial having the potential for the development of sustained-release drug delivery system following zero-order kinetics.

Organic acid treatment for removal of epiphytic Ulva L. attached to Sargassum fusiforme seedlings

The attachment of epiphytes to Sargassum fusiforme seedings has become a serious problem in S. fusiforme aquaculture. In this study, we investigated the effect of citric acid on the attachment of Ulva lactuca to S. fusiforme seedlings. Seedlings of S. fusiforme were treated with different concentrations of citric acid (0.05 mol·L−1, 0.08 mol·L−1, 0.15 mol·L−1) for different times (1, 3 and 5 min) and the death rate of the attached U. lactuca was measured. Citric acid treatment caused the death of U. lactuca, with the death rate increasing gradually with increasing concentrations of citric acid and treatment time. However, treatment with a high concentration of 0.15 mol·L−1 citric acid for 5 min impaired electron transfer of the S. fusiforme seedlings, decreasing photosynthesis and causing irreversible damage to the seedlings, and eventually resulting in the rotting and subsequent death of the seedlings. Treatment of the S. fusiforme seedlings with 0.08 mol·L−1 citric acid for 3 min was an optimal condition for the complete removal of epiphytic U. lactuca. Furthermore, subsequent culture of the treated seedlings by this optimal condition in the presence of 1.5 mg/L α-naphthaleneacetic acid during the recovery process was conducive to the normal growth of the S. fusiforme seedlings.

Citric acid as environment friendly crease-resistance finishing agent for silk fabric combined by ß-cyclodextrin

PurposeThe purpose of this paper is to assess the possibility of cross-linking silk fabric using citric acid (CA) as the cross-linking agent and nano-TiO2 (NTO) particles as a catalyst at low temperature and under UV irradiation. This paper also assesses the possibility of treated samples with suitable combinations of CA and NTO to impart multiple functional properties such as self-cleaning and antimicrobial properties.Design/methodology/approachIn this research, ß-cyclodextrin (ß-CD) grafted onto silk fabric using CA as a crosslinking agent and NTO particles as a catalyst through a pad-dry-cure technique and with UVA irradiation. The effects of different concentrations of CA, ß-CD and NTO particles on some properties of the treated samples are evaluated, and the optimum finishing conditions are obtained. The author also investigated the washing durability of the modified product after ten times of washing.FindingsThe results showed that CA plays the role of a linking agent through an esterification reaction with the hydroxyl groups of both ß-CD and silk fabrics and improves the durability of materials on the textile surface. Also, the silk fabrics treated with CA only were found to have excellent photocatalytic properties and better antibacterial activity than the control sample and the fabrics treated with a mixture of ß-CD/CA.Originality/valueThis study was conducted to achieve multiple functions such as antibacterial and photocatalytic activities, good dry crease recovery angle and wet crease recovery angle behavior without a significant adverse effect on the Yellowness index and tensile properties for treated silk fabrics.

Changes in biomass, photosynthetic efficiency, and total lipid content of Nannochloropsis oculata in response to metabolic intermediates and antioxidant

To study the effects of exogenous metabolic intermediates and antioxidant on Nannochloropsis oculata microalgae strain, the growth performance, biomass productivity, photosynthetic efficiency, and total lipid content were investigated by lab-scale cultivation experiments. Specifically, N. oculata was cultured in f/2 medium supplemented with different concentrations of citric acid or malic acid (0.050, 0.150, 0.750 g L−1) and KI (0.025, 0.050, 0.100, and 0.500 g L−1) to examine the physiological and biochemical effects on the widely distributed marine algae N. oculata. Results showed that the biomass and photosynthetic efficiency showed a downward trend with increasing citric acid and malic acid concentrations, and the low concentrations of metabolic intermediate treatments could enhance the lipid accumulation. The highest lipid content (0.295 or 0.245 g total lipid per gram of dry biomass) was found in cells treated with 0.15 g L-1 of citric acid and malic acid, which was about 28.45% and 6.99% higher than that growing in the culture lacking metabolic intermediates. Compared with malic acid, citric acid had better effect. Furthermore, potassium iodide (KI), an antioxidant, could also boost the lipid content of N. oculata with slight declining biomass productivity, and the highest lipid content (0.300 g total lipid per gram of dry biomass) was found in cells treated with 0.100 g L-1 of KI, which was about 28.08% higher than that growing in the culture lacking KI, indicating that KI may be a potential factor to increase the lipid content of algae cells. These findings not only provide insight into the response mechanism of N. oculata to exogenous metabolic intermediates and antioxidant but also help further broaden the key regulatory factors involved in the lipid accumulation within algal cells.

Effects of Syrup Solution with Different Concentrations of Citric Acid on Quality and Storage Life of Canned Litchi

Litchi fruit is a drupe or stone fruit. It is conical, heart-shaped or spherical with a thick leathery, indehiscent pericarp at maturity. Litchi is known for its pleasant flavour and juicy aril with attractive red colour pericarp. It is an excellent source of vitamins and minerals. Litchi fruits are generally eaten fresh because of their very short storage life and it ripens quickly, short production period and shelf life. Such fruit may be converted into value-added products such as juice, jelly, squash, canned litchi, nuts, and frozen litchi. The most common process to preserve litchi is canning. The aim of this study was to evaluate the quality and storage of canned litchi affected by syrup solution with different citric acid concentrations. The experiment was conducted at the laboratory of Postharvest Technology Department, ACARE, Yezin Agricultural University by using a randomized complete block design with four replications. The treatments were the litchi flesh and syrup which consisted of sucrose, distilled water without citric acid is treated as control and others are treated with citric acid (0.2% and 0.4%) filled in a glass jar stored at room temperature. Data on total soluble solid, pulp firmness, pulp colour (a*), total titratable acidity, pH, total sugar, reducing sugar, non-reducing sugar, ascorbic acid, total phenolics content and microbial analysis were collected and analysed. The canned litchi slightly increased in pulp colour with a slightly decrease in pH value. The more the citric acid% in canned litchi is, the more the pulp colour changed with the decrease in pH value along the storage periods is. There were no significant changes in total soluble solid and pulp firmness of canned litchi till the end of the storage. There was decreased in total sugar, non-reducing sugar and total titratable acidity. However, there were increased in reducing sugar, ascorbic acid and total phenolics content. There was no occurrence of total viable count, yeasts and moulds in canned litchi throughout the storage periods.

Simultaneous Dyeing and Finishing of Cotton Fabric in Presence of Starch Nanoparticles as Reinforcement Agent Using Citric Acid Based Finishing Formulation

ABSTRACT To augment high performance, coloration and functional finishing onto cotton fabrics; novel approach for simultaneous dyeing and finishing in addition to reinforcement effect were applied by conventional pad-dry-cure method in one step. This was done to explore the potential of reduction in energy consumption and production time as well as dyes and chemicals. For this purpose, our previously prepared starch nanoparticles (SNPs) as a reinforcement biopolymer were incorporated in cross-linking formulation of cotton fabrics embracing different concentrations of citric acid and cationic dyes, i.e., Methylene Blue and Crystal Violet in presence of sodium hypophosphite as a proficient catalyst at 1500C for 2 minutes. Evaluation of the treated fabric performance with respect to color strength (K/S), fastness properties to light, rubbing and perspiration, add on %, dry wrinkle recovery angles, tensile strength, fabric stiffness, antibacterial effect and ultraviolet protection factor were appraised. It is seen from the obtained results that; the simultaneously dyed and finished fabric in presence of SNPs showed higher color strength, dry wrinkle recovery angle, tensile strength, fabric stiffness, antibacterial and UPF functionalities in addition to considerable light, rubbing and perspiration fastness in comparison with untreated fabric. Besides, FTIR spectra exhibited the chemical structure of treated fabrics with respect to the presence of the ester crosslinking and functional groups of cationic dyes in questions in comparison with untreated fabric. The durability of the imparted functional properties was confirmed also by washing test.