A comprehensive study of raw and roasted macadamia nuts: Lipid profile, physicochemical, nutritional, and sensory properties.

Macadamia nuts have high nutritional value and positive health attributes. Changes to the composition and availability of these compounds during roasting contribute to product quality. In this study, changes to the chemical composition of lipids (fatty acids, triglycerides, and free fatty acids) and other phytochemicals were analyzed, and a sensory evaluation was carried out of two major varieties of macadamia nuts planted in China, after roasting. Only small changes in fatty acid (FA) content and a slight decrease in total triglycerides (TAGs) were observed after roasting. The free fatty acid (FFA) content and the peroxide value were increased by roasting. The total available polyphenol content increased by 25.6% and the oxidative stability index of kernels increased by 21.6%. The sensory scores for taste and aroma were doubled by roasting. Overall, the sensory, nutritional quality, and oxidative stability of roasted macadamia nuts were greatly improved, compared with raw nuts.

Double Derivatization Strategy for High-Sensitivity and High-Coverage Localization of Double Bonds in Free Fatty Acids by Mass Spectrometry.

Free fatty acids (FFAs) are key intermediates of lipid metabolism that have a crucial role in many critical biological processes. The specific locations of carbon-carbon double bonds (C═C) in FFAs are often associated with distinct biological functions. Despite the rapid development of analytical techniques, identification of C═C locations in FFAs with more than three C═C bonds in complex biological matrices remains a challenge. Herein, we describe a double derivatization strategy, coupled with shotgun-mass spectrometry (MS), for unambiguous and sensitive determination of a high-coverage C═C bond (from 1 to 6) locations of FFAs. Our approach is based on combination of acetone labeling of C═C bonds and N,N-diethyl-1,2-ethanediamine (DEEA) labeling of carboxyl groups within FFAs. Acetone labeling of C═C bonds via photochemical reaction provides diagnostic ions, specific to C═C locations, and DEEA labeling of carboxyl groups significantly enhances MS response of diagnostic ions, by invoking a readily protonated tertiary amine group on FFA analytes. By exploiting this double derivatization strategy, the assignment of C═C locations of FFAs with more than three C═C bonds was achieved with high sensitivity (limit of quantitation (LOQ) 0.1-1.5 nmol/L). In contrast, such assignments were not possible by acetone labeling alone, because of the low sensitivity of diagnostic ions in negative ionization mode of MS. The applicability of our method was demonstrated by profiling of FFAs, including unsaturated FFA C═C positional isomers, in liver samples from mice with nonalcoholic fatty liver disease (NAFLD) and their lean controls. The study showed that the high-specificity and high-sensitivity method developed here is promising for accurate identification and quantitation of a wide array of FFAs in biological samples.

Finite Element Simulation Study of Ultrasonic Vibration-Assisted Tensile High-Volume Fraction SiCp/Al Composite.

Silicon carbide particle-reinforced aluminum matrix composite (SiCp/Al) has been widely used in the military and aerospace industry due to its special performance; however, there remain many problems in the processing. The present paper introduces an ultrasonic vibration tensile apparatus and a composite tensile specimen and performs Abaqus finite element simulation on high-volume SiCp/Al. The results show that the stress-strain curve increases linearly during conventional tensile strength; the intermittent vibration tensile strength is similar to the full course vibration tensile strength: The magnitude of the stress reduction increases as the amplitude of the ultrasound increases and the vibration frequency increases. The tensile rate is inversely proportional to the magnitude of the stress reduction, and in the ultrasonic parameters, the amplitude has the greatest influence on the magnitude of the stress reduction, followed by the tensile rate; additionally, the frequency has the least influence on the magnitude of the stress reduction. The experimental results show that the simulation results are consistent with the experimental results.

Profiling and quantification of aminophospholipids based on chemical derivatization coupled with HPLC-MS.

In this study, a novel strategy based on acetone stable-isotope derivatization coupled with HPLC-MS for profiling and accurate quantification of aminophospholipids (phosphatidylethanolamine and phosphatidylserine) in biological samples was developed. Acetone derivatization leads to alkylation of the primary amino groups of aminophospholipids with an isopropyl moiety; the use of deuterium-labeled acetone (d6-acetone) introduced a 6 Da mass shift that was ideally suited for profiling and quantification analysis with high selectivity and accuracy. After derivatization, significantly increased column efficiency for chromatographic separation and detection sensitivity for MS analysis of aminophospholipids was observed. Furthermore, an accuracy quantification method was developed. Aminophospholipids in biological samples were derivatized with d0-acetone; while more than two aminophospholipid standards were selected for each class of aminophospholipid and derivatized with d6-acetone, which were then used as the internal standards to typically construct a calibration curve for each class to normalize the nonuniformity response caused by the differential fragmentation kinetics resulting from the distinct chemical constitution of individual aminophospholipid species in the biological samples. The excellent applicability of the developed method was validated by profiling and quantification of aminophospholipids presented in liver samples from rats fed with different diets.

Molecular adsorbent recirculating system in dealing with maternal Amanita poisoning during the second pregnancy trimester: a case report.

BACKGROUND: A 27-year-old woman in her 20th week of pregnancy was hospitalized because of food poisoning caused by Amanita phalloides. METHODS: Previously extracorporeal purification treatments with 2 times of hemodialysis plus hemoperfusion and a high volume therapeutic plasma exchange (PE) in addition to intensive medication during the first 8 days failed to improve hepatic encephalopathy (HE) and liver function but developed deep coma with severe blood chemistry and signs of threatened abortion. RESULTS: Treatments with intermittent molecular adsorbent recirculating system (MARS) for 3 times resulted in an immediate improvement of liver function and clinical symptoms including HE and threatened abortion until her fully recovery. When the life-threatening maternal illness was cured gestation went on until premature birth at the 36th week of pregnancy, and the infant underwent an undisturbed development. CONCLUSION: MARS method appears to be an optimal therapy for patients with acute liver failure secondary to cytoxic mushroom poisoning during pregnancy.