Tolgahan Kocadağlı

Determination of melatonin and its isomer in foods by liquid chromatography tandem mass spectrometry.

This study aimed to develop a reliable analytical method for the determination of melatonin and its isomers in various food products. The method entails ethanol extraction of solid samples (or dilution of liquid samples) prior to liquid chromatography coupled to triple quadruple mass spectrometry (LC-MS/MS) analysis of target analytes. The method was in-house validated and successfully applied to various food matrices. Recovery of melatonin from different matrices were found to be 86.0 ± 3.6%, 76.9 ± 5.4%, 98.6 ± 6.4%, and 67.0 ± 4.5% for beer, walnut, tomato and sour cherry samples, respectively. No melatonin could be detected in black and green tea, sour cherry, sour cherry concentrate, kefir (a fermented milk drink) and red wine while the highest amount of melatonin (341.7 ± 29.3 pg/g) was detected in crumb. The highest amounts of melatonin isomer were detected in yeast-fermented foods such as 170.7 ± 29.9 ng/ml in red wine, 14.3 ± 0.48 ng/ml in beer, and 15.7 ± 1.4 ng/g in bread crumb.

Model studies on the role of 5-hydroxymethyl-2-furfural in acrylamide formation from asparagine.

This study aimed to investigate the mechanism of acrylamide formation during heating asparagine (ASN) at elevated temperatures with glucose (GLC), and 5-hydroxymethyl-2-furfural (HMF). The results revealed that HMF rapidly reacted with ASN, leading to acrylamide formation. The ASN-HMF model system generated acrylamide more efficiently than the ASN-GLC model system during heating at 180°C. A significantly higher amount of 3-aminopropionamide (3-APA) was formed in the ASN-HMF model system than in the ASN-GLC model system within 5min at 180°C. The amount of 3-APA decreased after 5min of heating in both model systems while the amount of acrylamide continued to increase in the ASN-HMF model system. In-depth high resolution mass spectrometry analyses of reaction products formed in the model systems together with the kinetic data suggested that HMF is a potent carbonyl accelerating acrylamide formation during heating. 3-APA was found as one of the key intermediates leading to acrylamide formation.

In depth study of acrylamide formation in coffee during roasting: role of sucrose decomposition and lipid oxidation

Coffee, as a source of acrylamide, needs to be investigated in depth to understand the contribution of different precursors. This study aimed to investigate the contributions of sucrose decomposition and lipid oxidation on acrylamide formation in coffee during roasting. Coffee beans and model systems were used to monitor the accumulation of neo-formed carbonyls during heating through sucrose decomposition and lipid oxidation. High resolution mass spectrometry analyses confirmed the formation of 5-hydroxymethylfurfural (HMF) and 3,4-dideoxyosone, which were identified as the major sugar decomposition products in both roasted coffee and model systems. Among others, 2-octenal, 2,4-decadienal, 2,4-heptadienal, 4-hydroxynonenal, and 4,5-epoxy-2-decenal were identified in relatively high quantities in roasted coffee. Formation and elimination of HMF in coffee during roasting had a kinetic pattern similar to those of acrylamide. Its concentration rapidly increased within 10 min followed by an exponential decrease afterward. The amount of lipid oxidation products tended to increase linearly during roasting. It was concluded from the results that roasting formed a pool of neo-formed carbonyls from sucrose decomposition and lipid oxidation, and they play certain role on acrylamide formation in coffee.

Compositional, nutritional, and functional characteristics of instant teas produced from low- and high-quality black teas.

Two types of instant teas produced from low- and high-quality black teas were examined for their proximate composition, dietary fiber, minerals, water-soluble vitamins, total phenolic content, various antioxidant assays, phenolics (flavanols, condensed phenolics, and phenolic acids), alkaloids, and carotenoids as well as taste-active compounds (sugars, organic acids, and free amino acids). Some variations, albeit to different extents, were observed (p < 0.05) among these parameters between instant teas produced from low- and high-quality black teas. With respect to proximate composition, carbohydrate was the predominant component (56.68-59.84 g/100 g), followed by protein (19.31-19.86 g/100 g). Ash, moisture, and, to a lesser extent, dietary fiber and fat were also present in both instant teas. Thirteen minerals, four water-soluble vitamins, six flavanols, two alkaloids, three condensed phenolics, one phenolic acid, and one carotenoid were identified. Total phenolic content varied between 17.35 and 17.82 g of gallic acid equivalents (GAE)/100 g instant tea. With regard to antioxidant activities, three different assays such as oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC), and cupric ion reducing antioxidant capacity (CUPRAC) were measured. No significant differences (p > 0.05) in total phenolic, ORAC, TEAC, and CUPRAC contents between low- and high-quality instant teas were observed. With regard to taste-active compounds, 3 sugars, 5 organic acids, and 18 free amino acids were positively identified, of which fructose, tannic acid, and theanine predominated, respectively. The present work suggests that despite some differences, instant teas produced from low- and high-quality black teas should not be distinguished on the basis of their compositional, nutritional, and functional characteristics as well as taste-active compounds.

Formation of melatonin and its isomer during bread dough fermentation and effect of baking.

Melatonin is produced mainly by the pineal gland in vertebrates. Also, melatonin and its isomer are found in foods. Investigating the formation of melatonin and its isomer is of importance during bread dough fermentation and its degradation during baking since bread is widely consumed in high amounts. Formation of melatonin was not significant during dough fermentation. The melatonin isomer content of nonfermented dough was found to be 4.02 ng/g and increased up to 16.71 ng/g during fermentation. Lower amounts of isomer in crumb and crust than dough showed that the thermal process caused a remarkable degree of degradation in melatonin isomer. At the end of the 180 min fermentation Trp decreased by 58%. The results revealed for the first time the formation of a melatonin isomer in bread dough during yeast fermentation.

Investigation of α-Dicarbonyl Compounds in Baby Foods by High-Performance Liquid Chromatography Coupled with Electrospray Ionization Mass Spectrometry

Baby foods are exposed to elevated temperatures during processing treatments such as sterilization or spray drying. These treatments decompose sugars leading to the formation of α-dicarbonyl compounds that are of importance since they have been associated with several metabolic disorders. In this study, an analytical method based on high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to determine α-dicarbonyl compounds in baby foods. The method entailed aqueous extraction of α-dicarbonyl compounds from the samples and derivatization with o-phenylenediamine prior to chromatographic analysis. The results indicated that major degradation product was 3-deoxyglucosone in the samples including cereal-based infant formula, canned fruit and vegetable puree. Its concentration ranged between 3.9 and 827.1 mg/kg in infant formula and between 26.7 and 92.3 mg/kg in fruit puree samples. The concentrations of glucosone, 1-deoxyglucosone, 5-hydroxymethyl-2-furfural, furfural, glyoxal, methylglyoxal, and dimethylglyoxal levels were rather low.

Multiresponse kinetic modelling of Maillard reaction and caramelisation in a heated glucose/wheat flour system.

The study describes the kinetics of the formation and degradation of α-dicarbonyl compounds in glucose/wheat flour system heated under low moisture conditions. Changes in the concentrations of glucose, fructose, individual free amino acids, lysine and arginine residues, glucosone, 1-deoxyglucosone, 3-deoxyglucosone, 3,4-dideoxyglucosone, 5-hydroxymethyl-2-furfural, glyoxal, methylglyoxal and diacetyl concentrations were determined to form a multiresponse kinetic model for isomerisation and degradation reactions of glucose. Degradation of Amadori product mainly produced 1-deoxyglucosone. Formation of 3-deoxyglucosone proceeded directly from glucose and also Amadori product degradation. Glyoxal formation was predominant from glucosone while methylglyoxal and diacetyl originated from 1-deoxyglucosone. Formation of 5-hydroxymethyl-2-furfural from fructose was found to be a key step. Multi-response kinetic modelling of Maillard reaction and caramelisation simultaneously indicated quantitatively predominant parallel and consecutive pathways and rate limiting steps by estimating the reaction rate constants.

Formation of α‑dicarbonyl compounds in cookies made from wheat, hull‑less barley and colored corn and its relation with phenolic compounds, free amino acids and sugars

Cookies are baked at elevated temperatures to obtain a desirable browning and flavor development, which are provided by Maillard reaction and caramelization. The drawback here is the formation of α-dicarbonyl compounds, and they are associated with many metabolic disorders besides involving in the development of the desired flavor and browning. Cookies are one of the major sources of α-dicarbonyl compounds in diet. This study was performed to evaluate the formation of α-dicarbonyl compounds in cookies prepared from different cereal flours consisting of diverse natural phenolic compounds. Flours of white wheat, hull-less barley and yellow, dark-red, blue, dark-blue colored corns containing different amount of phenolic compounds were selected as raw materials. A negative correlation was observed between total phenolic compounds and glyoxal, methylglyoxal and diacetyl concentrations after baking. α-Dicarbonyl compound-trapping ability of phenolic compounds was attributed to this reduction during baking of cookies. On the other hand, higher amounts of 3-deoxyglucosone and 1-deoxyglucosone were observed with increasing total phenolic compounds, which was in accordance with the higher sucrose hydrolysis.

Effect of combining conventional frying with radio-frequency post-drying on acrylamide level and quality attributes of potato chips.

BACKGROUND In conventional manufacturing of potato chips, achieving an extremely low moisture content (2% by weight) in the final product necessitates prolonged exposure of potato slices to high oil temperatures. This promotes acrylamide formation and causes an exponential increase in acrylamide level toward the end of the frying process. In this regard, frying potato slices partially in hot oil followed by a radio-frequency (RF) drying treatment to selectively heat the remaining moisture appears to be a viable approach in terms of limiting acrylamide formation. RESULTS RF post-drying of partially fried potato slices resulted in lower acrylamide levels (80.4 ng g(-1) for control, 59.4 ng g(-1) for RF post-dried potato slices partially fried for 95 s, 54.8 ng g(-1) for RF post-dried potato slices partially fried for 80 s). This process modification also led a to 12% reduction in oil content in the final product. According to instrumental analysis results, RF post-dried samples had lower hardness and a slightly lower degree of browning in comparison to control. No significant difference (α = 0.05) was found between samples in terms of sensory characteristics. CONCLUSION Results demonstrate that RF post-processing may be an effective strategy for minimising acrylamide levels of potato chips without adversely affecting quality attributes.

Effects of Sodium Chloride, Potassium Chloride, and Calcium Chloride on the Formation of α-Dicarbonyl Compounds and Furfurals and the Development of Browning in Cookies during Baking

Effects of NaCl, KCl, CaCl2, NaHCO3, and NH4HCO3 on the formation of glucosone, 1-deoxyglucosone, 3-deoxyglucosone, glyoxal, methylglyoxal, diacetyl, 5-hydroxymethyl-2-furfural, and 2-furfural and browning were investigated in cookies. The presence of 1.5% NaCl, 1% KCl, and 1% CaCl2 on flour basis had no effect on α-dicarbonyl compounds, except 1-deoxyglucosone increased in the presence of KCl and CaCl2. The increase in 5-hydroxymethyl-2-furfural formation in the presence of NaCl, KCl, and CaCl2 did not relate to 3-deoxyglucosone formation and pH changes. NaCl, KCl, and CaCl2 increased browning in cookies. Model reaction systems indicated that NaCl, KCl, and CaCl2 enhance browning by increasing furfurals in caramelization. NaCl, KCl, and CaCl2 decreased browning intensity in a heated glucose-glycine system. Use of CaCl2 in cookies may considerably increase furfurals but not α-dicarbonyl compounds. Sodium reduction can be obtained by replacement with potassium without sacrificing the desired consequences of caramelization in sugar-rich baked goods.