Determination of perfluorinated compounds (PFCs) in solid and liquid phase river water samples in Chao Phraya River, Thailand

Perfluorinated compounds (PFCs), especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are fully fluorinated organic compounds, which have been used in many industrial applications. These chemicals have contaminated surface water all over the world even in developing countries like Thailand. The previous study showed the contamination in Chao Phraya River in 2006 and 2007. The purposes of this field study were to determine the solid and liquid phase of PFCs contamination in Chao Phraya River and to compare the changes of PFC concentration in 2008. Surveys were conducted in the lower reach of Chao Phraya River in the industrialized area. A solid phase extraction (SPE) coupled with HPLC-ESI-MS/MS were used for the analysis for ten PFCs. Ten PFCs were analyzed to identify the contamination in both solid and liquid phases. PFCs were detected in both the solid and liquid phase in every sample. PFOA was the most dominant PFC while PFPA and PFOS were also highly detected in most samples. The average loadings of PFPA, PFOA and PFOS in Chao Phraya River were 94.3, 284.6 and 93.4 g/d, respectively. PFOS concentrations did not show differences between 2006 and 2008. However, PFOA concentrations were higher in 2008/5/26, while comparing other samplings. The ratio of solid:liquid PFPA (2.1:1.0) [(ng/g)/(ng/L)] was lower than PFOA (13.9:1.0) [(ng/g)/(ng/L)] and PFOS (17.6:1.0) [(ng/g)/(ng/L)]. The shorter chain (more hydrophilic) PFC was better to dissolve in water rather than adsorb onto suspended solids. PFOS also showed more potential to attach in the suspended solids than PFOA.     

Effect of Drying Methods on Odorous Compounds and Antioxidative Activity of Gelatin Hydrolysate Produced by Protease from B. amyloliquefaciens H11

Gelatin hydrolysates with antioxidative activity produced by protease from Bacillus amyloliquefaciens H11 with different hydrolysis times were prepared. Alpha-amino group content and antioxidative activities increased with increasing hydrolysis time (p < 0.05). When gelatin hydrolysate prepared with hydrolysis time of 3 h (GH-3H) was subjected to freeze drying and spray drying, the powder obtained from spray drying showed a decrease in antioxidant activity as measured by DPPH and ABTS radical scavenging activities, ferric-reducing antioxidant power, and metal chelating activity. Spray-dried gelatin hydrolysate (GH-3H-SD) showed higher whiteness with lower fishy odor and off-odor associated with fermentation. This was concomitant with the decreases in several odorous compounds in the sample, except for nonanal, which was higher in comparison with the powder obtained by freeze drying. Thus, spray drying could be an effective drying method to improve color and reduce undesirable odor of gelatin hydrolysate.     

Polyisoprene modified poly(alkyl acrylate) foam as oil sorbent material

Biorenewable polyisoprene latex obtained from natural rubber, Hevea brasiliensis, was used to prepare the reusable polyisoprene–poly(alkyl acrylate) foam for petroleum‐based liquid absorption. The foam was produced via latex vulcanization and cured by steaming. The effect of various types of poly(alkyl acrylate) such as poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), and poly(butyl acrylate) (PBA) on oil sorption capacity of the foam were studied. Scanning electron microscope (SEM) images showed interconnected open‐cell macrostructure with the foam porosity greater than 75% and good compression set. The oil sorption capacity of the foam was in the range of 2.0–16.6 g g^?1. The addition of poly(alkyl acrylate) enhanced hydrophobicity and oil sorption capacity of the foam. The absorbed oil was easily recovered by squeezing and the foam can be reused up to 30 sorption–desorption cycles and still preserve high quality sorption. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42688.     

One‐step latex compounding method for producing composites of natural rubber/epoxidized natural rubber/aminosilane‐functionalized montmorillonite: enhancement of tensile strength and oil resistance

Montmorillonite (Mt) was intercalated with cetyltrimethylammonium bromide and functionalized with three types of aminosilane (3‐aminopropyltrimethoxysilane, n‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane and 3‐[2‐(2‐aminoethylamino)ethylamino]propyltrimethoxysilane). The modified Mt was compounded with natural rubber (NR)/epoxidized natural rubber (ENR) via one‐step latex compounding. The effect of the modified Mt content on the oil resistance and mechanical properties of the NR/ENR/modified Mt composites was investigated. The X‐ray diffraction patterns of the composites showed partial intercalation/exfoliation of the modified Mt in the rubber matrix. Cryogenic fracture and X‐ray fluorescence results revealed highly dispersed modified Mt in the composites in the presence of 10 phr ENR. All three aminosilane groups slightly improved the oil resistance, with the long‐alkyl‐length group producing the greatest improvement. The addition of a small amount of modified Mt improved both oil resistance and tensile strength by increasing in the average diffusion path length in the NR matrix and enhancing the interaction between the modified Mt and the epoxide groups in ENR. The addition of 1.0 phr of modified Mt increased the tensile strength by 18% and decreased the elongation at break by 12% compared with a neat NR/ENR blend. © 2017 Society of Chemical Industry     

Biochemical and gelling properties of tilapia surimi and protein recovered using an acid-alkaline process

The biochemical and gel properties of tilapia surimi prepared by a conventional washing method and protein isolated using alkaline-acid-aided processes were studied. Solubility and recovery of protein was found to be highest by using a conventional method, followed by an alkaline- and acid-aided process, respectively. Decreases in myoglobin and lipid contents were found in alkaline- or acid-aided process when compared to the conventional process (p < 0.05). The highest breaking force and deformation of kamaboko and modori gels was found in the gels prepared by the conventional washing method. Higher expressible water and whiteness were found in modori gels when compared to kamaboko gels. TCA-soluble peptide contents of conventional surimi gels were lower than those of acid- and alkaline-recovered protein gels. Degradation of myofibrillar protein was observed in acid-isolated protein. Microstructure of kamaboko gels showed more compact network than in modori gels in both conventional surimi and protein recovered using the pH-shift process.     

Re-extraction,Recovery, and Characteristics of Skin Gelatin from Farmed Giant Catfish

This study was aimed to investigate the re-extraction process for gelatin recovery from the skin of farmed giant catfish. The first extraction was done by incubating the acid-treated fish skin at 45 °C for 12 h. The remnant was re-extracted at temperatures of 60–90 °C for 1–12 h. The gelatin yield of the first extraction was 10.14%, while the re-extraction at high temperature provided higher recovery (19.5%). Low band intensity of α₁ and α₂ chains of gelatin was observed when it was re-extracted at high temperature for a longer time. The absorption bands of amide I and II from both extracted gelatins were similar. Low-transition temperature with high transition enthalpy of gelatin extracted at 90 °C was observed. The obtained results suggested that the re-extraction process could be applied as a supplemental step for other sources to obtain high recovery with the desired properties.