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   

Argon Plasma Treatment of Tapioca Starch Using a Semi-continuous Downer Reactor

To develop a novel modification process of tapioca starch using low-pressure argon plasma treatment in a large-scale production, a semi-continuous downer reactor was designed to provide a production rate of 0.1–0.5 kg per cycle. Physicochemical and rheological properties of plasma-treated starch were investigated in order to predict the phenomena occurred during the plasma treatment. Native tapioca starch (NTS) was plasma-treated for 1, 3, or 6 cycles, which were referred to as PTS-1, PTS-3, or PTS-6 samples, respectively. Plasma treatment of the NTS resulted in a significant decrease (P?<?0.05) in paste clarity and Rapid Visco Analyzer (RVA) breakdown viscosity, and an increase in gel strength of starch. The PTS-1 had the lowest paste clarity of 39.85 %T at 650 nm and breakdown viscosity of 29.71 Rapid Visco Unit (RVU), and the highest gel strength, e.g., G′?=?5.47ω ^0.32. With increasing the number of treatment cycles, i.e., the PTS-3 and PTS-6, the paste clarity and breakdown viscosity significantly increased (P?<?0.05), while the gel strength decreased. The Fourier transform infrared (FTIR) spectroscopy via relative areas of C–O–C peaks indicated that the PTS-1 had a significant increase (P?<?0.05) in the C–O–C cross-linked bonds compared to the NTS, but the effect of depolymerization could further suppress the cross-linking reaction when the number of treatment cycle was increased. Taking an advantage of a very short residence time (less than 0.3 s) in the plasma downer reactor, the semi-continuous process of starch modification could be developed for a commercial production of non-chemically modified starch with a relatively low degree of cross-linking.     

Color and hardness of durian chips irradiated by controlled low power microwave

Durian cv. Monthong was dried by using controlled low power microwave at atmospheric pressure. Although the hardness of durian chips was higher than that obtained from microwave drying in vacuum, it was comparable to the hardness of conventional products. According to Hunter Lab color parameters, durian surfaces became lighter but their yellowness was decreased after the microwave drying. Compared between 16 and 27 W irradiations, the higher power led to the increase in lightness and yellowness. Cross-sectional micrographs revealing the porous structure confirmed that a lower hardness was obtained in the case of 16 W.     

Practical use of β-carotene-loaded nanoemulsion as a functional colorant in sausages made from goat meat surimi-like material

The potential applicability of β-carotene-loaded nanoemulsion (CNE) as a natural colorant in non-smoked sausage made from goat meat surimi-like material (GMS) was elucidated. The effect of CNE content (0–30 g 100 g⁻¹) on the physicochemical characteristic, oxidative stability and β-carotene remaining during cold storage (4 °C) was determined. The higher the CNE, the greater the a*, b* and redness index with the lower L*, and colour likeness score. CNE content had a little impact on the moisture content, a_w and pH of sausages over storage period. However, the expressible drip, breaking force and deformation were largely influenced by the CNE content. All CNE-containing sausages displayed a superior oxidative stability to control. Among CNE-incorporated samples, the lowest lipid oxidation and β-carotene degradation were noticeable in the sausage with 10 g 100 g⁻¹ CNE. Thus, the CNE at 10 g 100 g⁻¹ was a promising functional colorant for emulsion sausage made from GMS.     

Development of a compact permanent magnet helicon plasma source for ion beam bioengineering

A compact helicon plasma source was developed as a millimeter-sized ion source for ion beam bioengineering. By employing a stacked arrangement of annular-shaped permanent magnets, a uniform axial magnetic flux density up to 2.8 kG was obtained. A cost effective 118 MHz RF generator was built for adjusting forward output power from 0 to 40 W. The load impedance and matching network were then analyzed. A single loop antenna and circuit matching elements were placed on a compact printed circuit board for 50 Ω impedance matching. A plasma density up to 1.1 × 10(12) cm(-3) in the 10 mm diameter tube under the magnetic flux density was achieved with 35 W applied RF power.     

Facile preparation of polybenzoxazine-based carbon microspheres with nitrogen functionalities: effects of mixed solvents on pore structure and supercapacitive performance

In this study, polybenzoxazine (PBZ)-based carbon microspheres were prepared via a facile method using a mixture of formaldehyde (F) and dimethylformamide (DMF) as the solvent. The PBZ microspheres were successfully obtained at the F/DMF weight ratios of 0.4 and 0.6. These microspheres exhibited high nitrogen contents after carbonization. The microstructures of all the samples showed an amorphous phase and a partial graphitic phase. The porous carbon with the F/DMF ratio of 0.4 showed significantly higher specific capacitance (275.1 F∙g^‒1) than the reference carbon (198.9 F∙g^‒1) at 0.05 A∙g^‒1. This can be attributed to the synergistic electrical double-layer capacitor and pseudo-capacitor behaviors of the porous carbon with the F/DMF ratio of 0.4. The presence of nitrogen/oxygen functionalities induced pseudo-capacitance in the microspheres, and hence increased their total specific capacitance. After activation with CO₂, the specific surface area of the carbon microspheres with the F/DMF ratio of 0.4 increased from 349 to 859 m²∙g^‒1 and the specific capacitance increased to 424.7 F∙g^‒1. This value is approximately two times higher than that of the reference carbon. The results indicated that the F/DMF ratio of 0.4 was suitable for preparing carbon microspheres with good supercapacitive performance. The nitrogen/oxygen functionalities and high specific surface area of the microspheres were responsible for their high capacitance.