A novel technique for the reduction of pesticide residues by a combination of low-intensity electrical current and ultrasound applications: A study on lettuce samples.

In this study, effects of low-intensity electrical currents (200, 800 and 1400 mA), ultrasound frequencies (24 and 40 kHz) and their combinations were applied at the duration period of 2, 4, 6, 8, and 10 min for the degradation of captan, thiamethoxam and metalaxyl residues in lettuce samples. Residues of the pesticides were determined by gas chromatography with tandem mass spectrometry and electron capture detector. The results indicated that the combination of low-intensity electrical current and ultrasound was found to be effective for the reduction of the pesticides. The most effective combination was obtained to be current of 1400 mA and ultrasound frequency of 24 kHz at 10 min. Under this circumstance, 92.57, 81.99 and 93.09% of captan, thiamethoxam and metalaxyl residues were decreased, respectively. The findings suggest that the combination of low-intensity electrical current and ultrasound applications has an important potential for the degradation of pesticide residues.

Development of an analysis method for determination of sulfonamides and their five acetylated metabolites in baby foods by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (Orbitrap-MS).

A high sensitive and reliable multiresidue method was developed and validated for determination of twelve sulfonamides and five acetylated metabolites in baby foods by using UHPLC-Orbitrap-MS. The sample preparation included two extraction methods as QuEChERS and ASE. The original QuEChERS method was performed, whereas ASE method was optimized to achieve the best recovery for all analytes. UHPLC-Orbitrap-MS parameters were optimized to obtain good retention and separation in LC and high sensitivity and selectivity in MS. The performance of the method was evaluated according to the European Commision Decision 2002/657/EC. Matrix matched calibration curves showed good r2 (≥0.999) and LOQ was ranged from 0.10 to 0.55µg/kg. ASE was significantly more effective for extraction of the analytes (recovery ranged from 75.5 to 96.6% with RSD≤10.1%) than QuEChERS (recovery ranged from 60.9 to 85.9% with RSD≤19.1%). This method was applied to the analysis of 47 different baby foods and no positive samples were found.

Quality characteristics of gluten-free cookies made of buckwheat, corn, and rice flour with/without transglutaminase.

Buckwheat is one of the most valuable pseudo-cereals in terms of its nutritional composition, and it is suitable for celiac patients because of its gluten-free characteristic. However, gluten is the main structure-forming protein responsible for the development of structure in baked products. Therefore, it is a challenge to produce high-quality gluten-free products. Transglutaminase addition is a relatively common application used in the production of gluten-free baked goods. The objective of this study was to investigate the combination of buckwheat flour with rice and corn flour at different levels in gluten-free cookie formulations and the impact of transglutaminase on the quality of cookies. Quality parameters evaluated were proximal chemical composition, spread ratio, color, and textural parameters (hardness and fracturability). Spread ratio, protein, crude fiber, ash content, and also b* and hardness values were significantly (p < 0.05) affected by flour combinations. Further, addition of transglutaminase resulted in increased moisture content, spread ratio, and fracturability but decreased hardness values.

Kinetic and thermodynamic investigation of mancozeb degradation in tomato homogenate during thermal processing.

BACKGROUND: The kinetic and thermodynamic parameters of mancozeb degradation in tomato homogenates under the conditions prevailing in the manufacture of tomato products (at 60-100 °C for 0-60 min) were investigated. A gas chromatography-mass spectrometry method was used to analyse residual mancozeb in tomato homogenate. Ethylenethiourea (ETU), the main toxic degradation product of mancozeb, was measured by high-performance liquid chromatography (HPLC)-with photodiode array detector (PDA). RESULTS: The degradation of mancozeb and the formation of ETU in tomato homogenates were adequately described as first-order kinetics. Dependence of the rate constant followed the Arrhenius relationship. Apparent activation energies, temperature coefficients, half time and time to reduce to 90% of the initial value of mancozeb were calculated as kinetic parameters. The thermodynamic parameters of mancozeb were also described as Δg(d) = - 2.440 and 7.074 kJ mol⁻¹; Δh(d) = - 32.555 and - 42.767 kJ mol⁻¹; Δs(d) = - 0.090 and - 0.150 kJ mol⁻¹ K⁻¹; K(e) = 0.414 and 9.797 L g⁻¹ for 333 and 373 K respectively. CONCLUSION: Current findings may shed light on the reduction of mancozeb residue and its toxic degradation product during thermal processing of tomatoes and may also be valuable in awareness and prevention of potential risks from dietary exposure.

Functional characteristics of egg white proteins within wheat, rye, and germinated-rye sourdoughs.

Egg white (EW) proteins are functional proteins, which possess certain biological activities (antimicrobial, antigenic, and peptidase-inhibitory) that may influence the food processing or vice versa can be affected by processing. This study investigated the behavior of EW proteins within sourdough systems with respect to proteolysis and fermentation parameters, and the ability of EW to build foam structures with sourdoughs. Of the EW proteins, ovotransferrin was hydrolyzed in all sourdoughs (wheat, rye, and germinated-rye), whereas the breakdown of ovalbumin was specific for germinated-rye sourdoughs, with the cysteine endopeptidases being responsible for the hydrolysis. The presence of EW in sourdough fermentations had no influence on the prolamin hydrolysis or the growth of starter culture, indicating that the peptidase-inhibitory and antimicrobial properties of EW play no important role in sourdoughs. EW foams, however, appeared as potential structure builders in sourdough applications and could serve as alternative structural agents in the production of baked goods with low gluten content.