Potential Production of Healthier Protein Isolate from Broiler Meat using Modified Acid-Aided pH Shift Process

Protein isolates from broiler meat were produced using acid-aided process (AP) with some modifications including prewashing prior to pH shift process (PW), homogenisation with 5 mM citric acid plus 8 mM CaCl₂ (CA) and homogenisation with 5 % ethanol (EA). Significant reduction of total cholesterol, nucleic acids and haemoproteins with improved protein yield and whiteness of the isolate was obtained from all modified process (p?<?0.05). CA was the most effective method in elimination of cholesterol (p?<?0.05). However, PW was the best way to remove nucleic acids and haem proteins (p?<?0.05). Among modified processes, CA gel tended to show the highest breaking force, deformation and whiteness but PW gel had the lowest expressible drip (p?<?0.05). EA possessed a negative effect on gel-forming ability. Therefore, CA or PW was a promising means to produce functional protein isolate with reduced nucleic acids, haem pigments and cholesterol.     

Physicochemical and gelling properties of short-bodied mackerel (Rastrelliger brachysoma) protein isolate prepared using alkaline-aided process

This study demonstrated the characteristics and gel properties of short-bodied mackerel (Rastrelliger brachysoma) surimi prepared by the conventional washing process and protein isolate prepared by alkaline solubilization process without and with prewashing. A decrease in Ca²⁺-ATPase activity (P < 0.05), with changes in the tryptophan fluorescence intensity of natural actomyosin, was observed in protein isolate from alkaline solubilization process. However, higher reactive sulfhydryl (SH) content was found in protein isolate, compared with that in conventional surimi (P < 0.05). Generally, the higher amounts of lipid and myoglobin in fish mince were removed by using the alkaline-aided process, compared with the conventional process (P < 0.05). Protein isolate from the alkaline solubilization process formed gels with higher breaking forces than conventional suirmi, especially with 2-step heating (40 °C, 30 min/90 °C, 20 min) (P < 0.05). The lowest expressible moisture was found in the gel of protein isolate prepared by alkaline solubilization process (P < 0.05). However, the highest whiteness was found in the conventional surimi gel prepared by 2-step heating (P < 0.05). Protein isolate prepared by the alkaline solubilization process yielded superior gels compared with the conventional surimi. Therefore, it can be concluded that the gelling properties of surimi or protein isolate are governed by the physicochemical properties of proteins and are affected by processing conditions.     

Plasma nano-modification of poly(ethylene terephthalate) fabric for pigment adhesion enhancement

Poly(ethylene terephthalate) (PET) fabrics were modified by treating with radio frequency (RF) plasma of different gases, including argon (Ar), nitrogen (N2), oxygen (O2) and sulfur hexafluoride (SF6), under varied power (50-150 watt) and time period (0.5-20 min). Observations indicated that plasma has affected the morphology and roughness of PET fiber surface in the nano-scale level. After plasma treatment, test patterns were printed by inkjet printer directly onto the sample surface. The enhancement of color printing performance on PET fabric by plasma treatment was evaluated by color spectroscopy. The surface nano-modified PET fabrics by Ar, N2, O2, and SF6 plasmas all exhibited enhanced color yield. AFM, SEM, FTIR-ATR and XPS results suggested that the improved pigment color yield was neither clearly contributed by the wettability of the fabrics nor the polar group induced onto the fiber surfaces but rather mainly by the alteration of surface roughness.     

Physicochemical properties and gel-forming ability of surimi from three species of mackerel caught in Southern Thailand

Physicochemical and gelation properties of surimi prepared from three species of mackerel were investigated. The highest whiteness with the lowest redness index corresponding to the lowest myoglobin content especially its oxidised form, metmyoglobin, was found in short-bodied mackerel (Rastrelliger brachysoma) surimi (p < 0.05). Frigate mackerel (Auxis thazard) surimi contained the highest lipid content (p < 0.05). The pH of all surimi was in the range of 6.58–6.80. The highest sulfhydryl group and Ca²⁺-ATPase activity was found in natural actomyosin extracted from short-bodied mackerel surimi (p < 0.05). The highest TCA-soluble peptide content was found in frigate mackerel surimi gels (p < 0.05). Kamaboko gel of short-bodied mackerel surimi exhibited the highest breaking force with the lowest expressible drip (p < 0.05). Heating regime had no effect on deformability of gels from Indian mackerel (Rastrelliger kanagurta) and short-bodied mackerel but not for frigate mackerel. The highest metmyoglobin content with the lowest whiteness was found in frigate mackerel surimi gel (p < 0.05). Therefore, short-bodied mackerel was the best suited for the production of surimi with superior functional attributes including whiteness and gel-forming ability.     

Aromatic phosphorodiamidate curing agent for epoxy resin coating with flame-retarding properties

Two organophosphorus-based diamines containing aromatic moieties has been synthesized and used as a curing and flame retarding agent for epoxy resin coatings. This agent functions not only as a crosslinking materials in the Epon 828 epoxy resin curing process but also as a fire retarding compound to produce thin films or composites upon curing. Phenyl phosphonic ethylene diamine diamide (PPEDD) was synthesized via condensation of phenylphosphonic dichloride (PPDC and ethylenediamine (EDA)). Likewise, phenyl phosphonic p-phenylene diamine diamide (PPPDD) was synthesized via condensation of PPDC and p-phenylenediamine (PDA). Kinetics studies of the curing reaction of the two phosphorodiamidates were carried out in comparison with the corresponding non-phosphorus containing reference crosslinking agents, EDA and PDA. Thermal stability of the cured epoxy were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Moreover, flame retardant properties of the materials was investigated by limiting oxygen index (LOI) measurements. The results show that epoxy resin cured with phosphorodiamidate possesses higher thermostability than that of the non-phosphorus containing counterpart. This is evident by a significantly higher amount of char formed upon burning. More importantly, the LOI of 27 and 31 was observed in the PPEDD-cured epoxy resin and PPPDD-cured epoxy resin compared with those prepared from non-phosphorus curing agents (20 for EDA and 21 for PDA). This was obtained only with approximately 2–3 wt.% of phosphorus content.     

Conductive Poly(3-methylthiophene) Thin Films

The work described herein represents an efficient method in the deposition of poly(3-methylthiophene),P3MeTh,thin films utilizing a microwave plasma system in combination with a simultaneous doping with iodine.It was envisaged that,an alternative poly(3-methylthiophene),P(3MeTh),with an electron donating methyl substituent,would reduce the degree of ring opening which reportedly occur to a certain extent during the plasma polymerization process of its parent compound polythiophene.An alkyl substituent would also increase the solubility of the materials.P(3MeTh)thin film deposition has been performed utilizing microwave-induced plasma polymerization in order to directly grow films on glass substrates.Moreover,simultaneous doping of the so-formed polymer with iodine has been carried out as opposed to the post-synthesis doping method.This is aimed to prolong electrical conducting lifetime of the materials.The synthesized films were characterized by attenuated total reflection fourier transform infrared(ATR FT-IR)spectroscopy and energy dispersive X-ray spectroscopy(EDS)to confirm the incorporation of iodine dopant into the films.Scanning electron microscopy showed uniformly deposited films.It has been observed that the electrical conductivity of the doped film is 2 orders of magnitude higher than the undoped counterpart.The doped fabricated films exhibited UV-vis spectra indicative of increased π-conjugation(536 nm).Furthermore,electrical conductivity of the in situ doped P(3MeTh)is more highly sustained over a longer period of time.     

Functional properties of pH-shifted protein isolates from bigeye snapper (Priacanthus tayenus) head by-product

The functional properties of pH-shifted protein isolates from bigeye snapper head were evaluated. Alkaline isolate showed a superior salt-solubility and gel forming ability to acid counterpart as indicated by a regular gel structure (i.e., imaged by scanning electron microscope) with higher gel strength and lower expressible drip (p < 0.05). Acid isolate exhibited higher surface hydrophobicity (p < 0.05) and thereby improved interfacial properties. Emulsifying activity index of acid isolate was lower than commercial whey protein and egg-white (p < 0.05) but its emulsion stability was better (p < 0.05). Both protein isolates had lower foamability than commercial proteins but their foam stability was not different (p > 0.05).     

Chemical deterioration and discoloration of semi-dried tilapia processed by sun drying and microwave drying

Drying methods can affect the chemical deterioration and discoloration of fish muscle. This study aimed to monitor the effect of microwave drying at different effective powers in comparison with sun drying on the physicochemical changes of semidried tilapia. Lipid deterioration, protein oxidation and discoloration of semidried tilapia (Oreochromis niloticus) muscle processed by sun drying and microwave drying were investigated. Results of the study revealed that the pH of microwaved tilapia was higher than that of the sun-dried tilapia (p?p?p?p?p?p?a* value with a significantly decreased redness index (p?相似文献   

Improved radical scavenging activity and stabilised colour of nipa palm syrup after ultrasound-assisted glycation with glycine

The effects of ultrasound-assisted glycation with 1 m glycine at room temperature in comparison with thermal glycation on the colour and radical scavenging activity of nipa palm (Nypa fruticans Wurmb.) syrup were investigated. The pH of both treatments decreased with increasing reaction time. The browning development occurred after induction period of 10 min for thermal glycation and 60 min for ultrasound-assisted glycation. A shorter time of ultrasound rendered the syrup light brown to amber in colour with some green. With long-term ultrasound, the syrup turned brighter, yellower and greener. The increased DPPH^· scavenging activity of the thermal syrup was due to the brown pigments as shown by a marked increase in the A₄₂₀ and a* value. The scavenging activity of ultrasound-treated syrup was improved by 53–57% due to the accumulation of UV-intermediate products as shown by a higher A₂₉₄/A₄₂₀. Thus, ultrasonication for 30–60 min was recommended in order to prevent dark colour development of the final syrup.