Addition Of Sorbic Acid Research Articles

Improved performance of layered double hydroxide/hydrogenated nitrile rubber composites by addition of sorbic acid

AbstractLayered double hydroxide (LDH) was in situ modified by sorbic acid (SA) and used to reinforce hydrogenated nitrile rubber (HNBR) by direct blending method. SA connected LDH and HNBR via grafting/coordination mechanism. The results showed that SA could effectively improve the interaction between LDH and HNBR and significantly improve the dispersion of LDH in the rubber matrix. In addition, zinc sorbate (ZDS) formed by the reaction of SA and zinc oxide (ZnO) could self‐polymerize with the initiation of Dicumyl peroxide to form poly‐zinc sorbate, which is conducive to the reinforcement of rubber. The LDH/HNBR composite with SA loading of 20 phr has the best comprehensive mechanical properties, including tensile strength of 39.31 MPa, tear strength of 62.38 kN/m, shore A hardness of 85.1°, and elastic modulus of 20.14 MPa, which is significantly better than the LDH/HNBR composite without addition of SA. Our work provides a practicable and effective methodology for in situ modification of LDH and fabrication of high‐performance rubber composites.

Ion-paired pirenzepine-loaded micelles as an ophthalmic delivery system for the treatment of myopia

Myopia is one of the most common ocular disorders for which standard treatments, such as refractive surgery, often involve invasive procedures. Pirenzepine (PRZ), a muscarinic receptor antagonist, has been recognized as a promising candidate for the treatment of myopia, but possesses poor ocular bioavailability. The overall objective of this study was to prepare PRZ-sorbic acid complexes suitable to be encapsulated into micelles with high efficiency for optimal ophthalmic delivery. The results demonstrated that sorbic acid, used as the counter ion, had the most significant effects in increasing the octanol–water distribution coefficient of PRZ as well as improving its corneal permeability in vitro among various counter ions tested. In vivo absorption results showed that a 1.5 times higher bioavailability was achieved by the addition of sorbic acid at a 1:1 ratio. Cytotoxicity studies in vitro and biocompatibility studies in vivo indicated that the micelles did not cause significant toxicities to the eyes.

Aqueous photochemical degradation of BDE-153 in solutions with natural dissolved organic matter

The compound 2,2′,4,4′,5,5′-hexabrominated diphenyl ether (BDE-153) is an intermediate photolytic product in the degradation of highly brominated diphenyl ethers to lower brominated forms. Herein, we report the effects of two natural organic matter (NOM) sources, Suwannee River fulvic acid (SRFA) and Pony Lake fulvic acid (PLFA), on BDE-153 photolysis in water. The rate constant (k) and half-life of BDE-153 was 2.26 × 10−2 min−1 and 30.72 min under UV–Vis irradiation (direct photolysis at λ > 290 nm). The k value for BDE-153 decreased markedly in the presence of NOM with a larger decrease in the presence of PLFA than SRFA. Electron spin resonance (ESR) demonstrated generation of free radicals in the photolytic process that mainly involved 1O2 and OH. The biomolecular k values for reaction of 1O2 and OH with BDE-153 were 3.65 × 106 and 7.70 × 108 M−1 s−1, respectively. The contribution of OH (28.7–31.0%) to the indirect photolysis of BDE-153 was higher than for 1O2 (12.9–14.9%). The photolytic rate of BDE-153 in oxygen-rich (aerated) solution was much slower than in oxygen-poor (nitrogen-sparged) conditions, demonstrating that 3NOM* is a more effective reagent for degradation of BDE-153 than 1O2. Addition of sorbic acid (a 3NOM* quencher) significantly reduced the photolytic rate of BDE-153 confirming the important role of 3NOM* in indirect photolysis. In the presence of NOM, BDE-153 indirect photolysis was facilitated mainly by reaction with 3NOM* and OH. To the best of our knowledge, this is the first comprehensive investigation of indirect photolysis of BDE-153 in water containing NOM.

Diels‐Alder adduct of sorbic acid and methyl ester of soyabean oil as substitute to conventional dimer acids

PurposeThe purpose of this paper is to synthesise new fatty dicarboxylic acid half ester (NFAHE) C25, which can be used as substitute to dimer/trimer acids commonly used (C36, 54) as basic raw materials for manufacture of polyamides for printing inks or as curing agents for epoxy paints and adhesives. This could be an economically viable synthesis by which the user could manufacture the finished products from relatively low cost raw materials.Design/methodology/approachVegetable oils have several double bonds that undergo large number of reactions. Diels‐Alder addition is one of them. Dimer acids have been produced by using these double bonds by reaction of two fatty acid molecules. Maleic acid, acrylic acid has also been used for this purpose. Sorbic acid is a derivative of alcohol and hence a renewable raw material. It is relatively less used by the coating chemists due to its relatively limited availability due to restricted uses.FindingsIt was found that sorbic acid reacts easily with unsaturated fatty acids. Its solubility in fatty acids and esters is limited. A common solvent that can be removed easily after the reaction was necessary. Cyclohexanone was found to meet this requirement. The resultant half ester of dicarboxylic acid could be easily converted to polyamides for curing epoxies.Practical implicationsThe user can manufacture his own dibasic/tribasic acid as a first step. As a source of methyl esters of fatty acids with iodine value about 110 to 130, vegetable oils such as soyabean oil can be used. Low value acid oils obtained from vegetable oil refining are also suitable. Bio diesel could be used directly. To account for large saturated fatty acids in bio diesel, corresponding trimer may be produced by appropriate addition of sorbic acid to fatty acid.Originality/valueThe process allows a manufacturer to develop low cost formulations for bulk products using simple chemistry that can be integrated in the existing process.

Significantly improved performance of rubber/silica composites by addition of sorbic acid

Sorbic acid (SA) was used to improve the performance of styrene–butadiene rubber (SBR)/silica composites by direct blending. The mechanisms for the significantly improved performance were studied by X-ray photoelectron spectroscopy, X-ray diffraction and by the determinations of bound rubber content and crosslink density. The strong interfacial bonding between silica and the rubber matrix resulted from SA-intermediated linkages. Significantly improved dispersion of silica by virtue of the interactions between silica and SA was found. Formation of zinc disorbate during compounding of composites was confirmed. The effects of SA content on vulcanization behavior, morphology, mechanical properties and abrasion loss of composites were studied. Significantly improved mechanical properties of SA-modified SBR/silica composites were demonstrated. Changes in vulcanization behavior, morphology and performance were correlated with the interactions between silica and SA and the largely improved dispersion of silica.

In vivo measurement of cytosolic and mitochondrial pH using a pH-sensitive GFP derivative in Saccharomyces cerevisiae reveals a relation between intracellular pH and growth

The specific pH values of cellular compartments affect virtually all biochemical processes, including enzyme activity, protein folding and redox state. Accurate, sensitive and compartment-specific measurements of intracellular pH (pHi) dynamics in living cells are therefore crucial to the understanding of stress response and adaptation. We used the pH-sensitive GFP derivative 'ratiometric pHluorin' expressed in the cytosol and in the mitochondrial matrix of growing Saccharomyces cerevisiae to assess the variation in cytosolic pH (pHcyt) and mitochondrial pH (pHmit) in response to nutrient availability, respiratory chain activity, shifts in environmental pH and stress induced by addition of sorbic acid. The in vivo measurement allowed accurate determination of organelle-specific pH, determining a constant pHcyt of 7.2 and a constant pHmit of 7.5 in cells exponentially growing on glucose. We show that pHcyt and pHmit are differentially regulated by carbon source and respiratory chain inhibitors. Upon glucose starvation or sorbic acid stress, pHi decrease coincided with growth stasis. Additionally, pHi and growth coincided similarly in recovery after addition of glucose to glucose-starved cultures or after recovery from a sorbic acid pulse. We suggest a relation between pHi and cellular energy generation, and therefore a relation between pHi and growth.

Effect of combined methods of preservation on the naturally occurring microflora of avocado purée

The effects of combining techniques such as addition of sorbic acid, modification of water activity ( a w), reduction of pH, modification of the packaging atmosphere and control of the storage temperature on the microbiological shelf life of avocado purée were evaluated during four months of storage. Results show that the addition of 300 mg/kg of sorbic acid can extend the stability of the product native microflora for storage periods of up to four months. Vacuum packaging as well as storage at 4 °C was also found to have a significant influence over the control of yeast and mould populations and could preserve avocado purées during 112 days without addition of antimicrobial. The addition of maltose to reduce a w to 0.96 resulted in slightly more stable purées but would impart important changes to the product palatability.

Degradation of the Lauric acid oils

The composition, properties, uses and degradation of the lauric acid oils have been discussed. Coconut and palm kernel oil contain approximately 40% medium chain fatty acids (C6:0–C12:0). The medium chain fatty acids in these oils are readily degraded by filamentous fungi belonging to the following genera, Penicillium, Aspergillus, Cladosporium, Fusarium, Trichderma and Monascus to give the methyl ketone one carbon atom less. This type of spoilage has been described as ketonic rancidity. Ketonic rancidity caused by Penicillium crustosum can be controlled by the total absence of fungal spores, a temperature less than 4°C, water activity less than 0·91; the addition of sorbic acid at 1000 mg/kg or by the absence of oxygen. Coconut oil is a better substrate for ketonic rancidity than palm kernel oil due to the higher concentration of medium chain fatty acids in the former.

Hay desiccation and preservation with potassium sorbate, potassium carbonate, sorbic acid and propionic acid

Three experiments were conducted to ascertain the effectiveness of sorbic acid or potassium sorbate in hastening the drying of cut alfalfa, thus decreasing the interval from cutting to baling, and to evaluate the effectiveness of sorbic acid or potassium sorbate compared with dry control or propionic acid as a forage preservative by measuring and comparing storage temperature, dry matter and chemical composition of treated and untreated alfalfa hay before and after storage. Second-harvest alfalfa was cut at the early bud stage, wilted in the field to approximately 30% moisture, and baled with the addition of various treatments. Treatments consisted of wet control 0.25, 0.5, 1, 2 and 4 g potassium sorbate kg −1 dry matter (DM). Addition of potassium sorbate to high-moisture alfalfa hay did not improve preservation when compared with untreated hay, with comparisons based on heating during storage, DM change, and chemical composition of hay obtained from storage. A solution containing 1, 2 or 4 g potassium sorbate kg −1 DM and 4 g potassium carbonate kg −1 DM was sprayed on third-harvest bud-stage alfalfa from a sprayboom mounted on the push-bar of a self-propelled mower conditioner. Forage loss of moisture during drying was monitored at regular intervals, and hay was baled into conventional rectangular bales when moisture reached 30%. Addition of potassium carbonate and potassium sorbate to alfalfa hay at cutting did decrease drying time and improved preservation when compared with untreated hay, with comparisons based on field drying time, heating during storage, DM change and chemical composition of hay obtained from storage. Second-harvest alfalfa was cut at the early-bud stage, wilted in the field to approximately 35% moisture and baled with the addition of various treatments. Treatments consisted of wet control, 5, 10, 15 g sorbic acid kg −1 DM and 15 g propionic acid kg −1 DM. Addition of sorbic acid to alfalfa hay at baling did not improve preservation when compared with untreated hay with comparisons based on heating during storage and DM losses. However, alfalfa hay harvested at 30% and treated with 15 g propionic acid kg −1 DM had interior bale temperatures that followed a similar pattern of dry control.

The effect of temperature, water activity and sorbic acid on ketone rancidity produced by Penicillium crustosum Thom in coconut and palm kernel oils

In a model system medium‐chain fatty acids (MCFA) C6–C12 in coconut and palm kernel oil are converted to methyl ketones, one carbon atom less than the parent fatty acids, by two strains of Penicillium crustosum Thom. Conversion rates of up to 32% were seen for decanoic acid at 25°C. The optimum temperature for ketone production was 25°C in liquid suspension culture. Coconut oil contains 3.23 mmol/g MCFAs compared with 2.34 mmol/g for palm kernel oil. Coconut oil is more prone to fungal spoilage (growth and ketone production) than palm kernel oil. The main end product of fermentation was 2‐undecanone reflecting the high concentration of dodecanoic acid in the substrates. Ketonic rancidity is fungal engendered. The reaction can be controlled by reducing the temperature (4°C), reducing the water activity (0.91) or by addition of sorbic acid (20 mmol/l).

Effects of Sorbic Acid and Temperature on Survival and Reproduction of Western Spruce Budworm (Lepidoptera: Tortricidae)

A bioassay was used to determine how addition of sorbic acid (0.63 and 1.26% dry mass) to an artificial diet affected survival of Choristoneura ocddentalis Freeman through all life stages of three generations. Development time of larvae and pupal weight were monitored. Development on diets with 0 or 1.26% sorbic acid was evaluated for insects that were held at 22 and 25°C. Experimental data were used to estimate population growth on the various diets tested. Addition of sorbic acid to the diet resulted in more rapid larval development and larger pupae, but survival through the pupal stage and viability of eggs were reduced. Decreasing the sorbic acid concentration from 1.26 to 0.63% greatly reduced the negative effects on survival, particularly in the F1 and F2 generations. Many of the pupae from the diet containing 1.26% sorbic acid exhibited morphological abnormalities characterized by deformed or missing wing pads. For diets with no sorbic acid. the 25°C temperature was clearly better than 22°C for C. ocddentalis survival, development time, and pupal weights. However, population growth at 22°C was better on the 1.26% sorbic acid diet.

SODIUM NITRITE AND SORBIC ACID EFFECTS ON Clostridium botulinum TOXIN FORMATION IN CHICKEN FRANKFURTER‐TYPE EMULSIONS

ABSTRACT C. botulinum growth and toxin production and residual nitrite depletion were studied in a mechanically deboned chicken meat (MDCM) frankfurter‐type product, during 27°C temperature abuse. A series of three trials were conducted in order to determine the effects of sodium nitrite and sorbic acid on the above parameters. Low nitrite concentrations (20 and 40 μg/g), did not influence C botulinum growth and toxin production. The addition of sorbic acid (0.2%) to these nitrite levels resulted in a significant extention of the time necessary for toxin to develop. The 0.1% sorbic acid level was ineffective. Nitrite concentrations of 156 μg/g doubled the time necessary, for botulinal toxin production, as did 0.2% sorbic acid alone. The magnitude of toxin production delay was increased five fold when 156 μg/g nitrite and 0.2% sorbic acid were combined. Nitrite depletion, was rapid during processing and 27°C incubation. Low residual nitrite concentrations were present for a longer time in nitrite‐sorbic acid combination treatments, indicating that the presence of sorbic acid may delay depletion of residual nitrite. Gas production and spoilage of the product followed the same rate of development as toxin.

The Preservative Effects of Sorbic Acid for Fish Sausage

Sorbic acid has been used as antiseptic for fish sausage, since the use of AF-2 [2-(furyl)-3-(5-nitro-2-furyl) acrylamide], which had been one of the effective preservatives for fish sausage, was prohibited in July of 1974. Therefore, the preservative effects of sorbic acid for fish sausage was reinvestigated in connection with pH value and storage temperature of the sausage. The results obtained are as follows.1) At storage temperature of 30°C, the shelf life of fish sausage with the pH values of lower than 5.9 was about one week. Additions of sorbic acid to the sausages at the level of 0.1 and 0.2% prolonged their shelf lives for one and two weeks respectively.2) At storage temperature of 10°C, the sausages with about 6.2 of pH did not show any sign of spoilage for the test period of 7 weeks without regard to the addition of sorbic acid. The same results were obtained at the elevated storage temperature of 15°C.3) From these results, it was presumed that fish sausages added at the level of 0.2% of sorbic acid could be preserved for at least two months at about 10°C, if the pH is adjusted to the suitable pH range in which sorbic acid shows effective bacteriostatic action.

Microbiological and Sensory Evaluation of a Dehydrated Turkey Meat Product

A dehydrated turkey meat product, “turkey jerky,” was prepared and tested for acceptance using microbial and sensory methods. Jerky was prepared with and without the addition of sorbic acid and evaluated organoleptically and microbiologically during five and seven months storage, respectively. Untreated samples of 18 and 30% moisture content were stored at both 5 and 25° C. Evaluation of untreated samples showed continuous microbial development in the 30% moisture product stored at 25° C. Sporadic recoveries of low levels of coagulase positive staphylococci and streptococci were made. Sorbic acid treated jerky samples were negative for food-borne pathogens and yielded low levels (< 100/g.) of organisms. Taste panel results indicated a preference for the 30% moisture product over the 18% moisture products when microbial growth in the 30% samples was controlled by refrigeration (5° C.) and/or sorbic acid treatment (0.07%).

A Bacteriological Study on the Effect of 2- (2-Furyl) -3- (5-nitro-2-furyl) -acrylamide and Sorbic Acid on the preservability of Vienna Sausage

The preservability of Vienna sausage, using the legally approved synthetic germicide 2- (2-furyl) -3- (5-nitro-2-furyl) -acrylamide (AF-2) and the preservative sorbic acid (SOA) was studied using laboratory produced samples. Results obtained were as follows.1. Tests for the presence or absence of Neto development, organoleptic tests, measurement of the numbers and species of bacteria developing at 10°C and 30°C and pH measurement revealed that preservability decreased according to the order of addition of pH depressing agent→addition of AF-2·SOA→addition of SOA→addition of AF-2→no addition. The highest degree preservability was achieved in samples coated with AF-2+SOA+pH depressing agent where the optimal pH was 5.9. However, considerable variation was noted in preservability among various samples of the same lot. Periods of maximal preservability also differed more than 10 days.2. The effect of addition of the synthetic germicide, (2- (2-Furyl) -3- (5-nitro-2-furyl) -acrylamide), and a preservative (sorbic acid) manifested itself at the optimal pH and cold temperatures. The maximal effect was obtained when the fundamental aspects of hygienic handling from production to sales were fulfilled. The actual preservation results were noted to be the total sum of all additives and handling procedures.3. The bacterial flora was definitely different between those samples containing the synthetic germicide plus preservative and those without additions. While lactobacilli were predominant in the former; micrococci, corynebacteria and lactobacilli were predominant in the latter. Alcaligenes species appeared and increased with elongated preservation times.

Prevention of Rancidity

The composition, properties, uses and degradation of the lauric acid oils have been discussed. Coconut and palm kernel oil contain approximately 40% medium chain fatty acids (C6:0–C12:0). The medium chain fatty acids in these oils are readily degraded by filamentous fungi belonging to the following genera, Penicillium, Aspergillus, Cladosporium, Fusarium, Trichderma and Monascus to give the methyl ketone one carbon atom less. This type of spoilage has been described as ketonic rancidity.Ketonic rancidity caused by Penicillium crustosum can be controlled by the total absence of fungal spores, a temperature less than 4°C, water activity less than 0·91; the addition of sorbic acid at 1000 mg/kg or by the absence of oxygen. Coconut oil is a better substrate for ketonic rancidity than palm kernel oil due to the higher concentration of medium chain fatty acids in the former.