Aytül Hamzalıoğlu

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.

Investigation and kinetic evaluation of the reactions of hydroxymethylfurfural with amino and thiol groups of amino acids

In this study, reactions of hydroxymethylfurfural (HMF) with selected amino acids (arginine, cysteine and lysine) were investigated in HMF-amino acid (high moisture) and Coffee-amino acid (low moisture) model systems at 5, 25 and 50°C. The results revealed that HMF reacted efficiently and effectively with amino acids in both high and low moisture model systems. High-resolution mass spectrometry (HRMS) analyses of the reaction mixtures confirmed the formations of Michael adduct and Schiff base of HMF with amino acids. Calculated pseudo-first order reaction rate constants were in the following order; kCysteine>kArginine>kLysine for high moisture model systems. Comparing to these rate constants, the kCysteine decreased whereas, kArginine and kLysine increased under the low moisture conditions of Coffee-amino acid model systems. The temperature dependence of the rate constants was found to obey the Arrhenius law in a temperature range of 5-50°C under both low and high moisture conditions.

Formation and elimination reactions of 5-hydroxymethylfurfural during in vitro digestion of biscuits

This study investigated the possible formation and elimination reactions of 5-hydroxymethylfurfural (HMF) with amino and sulfhydryl groups in commercial biscuits during simulated in vitro gastrointestinal digestion. At the end of gastric phase, significant increase was observed in HMF contents of biscuits (p<0.05). By high-resolution mass spectrometry (HRMS) analysis, it was confirmed that sugar dehydration products such as 3-deoxyglucosone and 3,4-dideoxyglucosone accumulated in biscuits during baking were converted to HMF under gastric conditions. However, reactions of HMF with amino acids proceeded with the progress of digestion. HRMS analysis in both HMF-amino acid model systems and in biscuits confirmed that formed HMF reacted with amino and sulfhydryl groups through Michael type addition. In addition, formation of Schiff base during intestinal phases led to a significant decrease in the concentrations of HMF (p<0.05).

Inhibitory effect of hawthorn extract on heterocyclic aromatic amine formation in beef and chicken breast meat

This study focused on the inhibitory effect of different levels of hawthorn extract (0, 0.5, and 1%) on the formation of heterocyclic aromatic amines (HAAs) in beef and chicken breast cooked by either pan-cooking or oven-cooking. All meat samples were cooked at three different temperatures (150, 200, and 250°C) and the levels of twelve HAAs were assessed (IQ, IQx, MeIQ, MeIQx, 4,8-DiMeIQx, 7,8-DiMeIQx, PhIP, harman, norharman, AαC, MeAαC, and Trp-P-2). Varying levels of IQ (up to 4.47ng/g), IQx (up to 0.69ng/g), MeIQ (up to 0.82ng/g), MeIQx (up to 1.01ng/g), 4,8-DiMeIQx (up to 0.10ng/g), 7,8-DiMeIQx (up to 0.23ng/g), PhIP (up to 0.75ng/g), harman (up to 2.15ng/g), norharman (up to 1.08ng/g), AαC (up to 1.86ng/g), MeAαC (up to 0.48ng/g), and Trp-P-2 (up to 12.88ng/g), were detected. Samples cooked at 150°C had very low amounts of HAAs, and the levels of HAAs increased gradually when the cooking temperature rose from 150 to 250°C. The total HAA content in chicken breast and beef ranged between not detectable to 17.60ng/g, and not detectable to 11.38ng/g, respectively. The inhibitory effects of hawthorn extract at 0.5% and 1% on total HAAs levels were found to be 12-100% and 19-97% in chicken breast, respectively, and 42-100% and 20-35% in beef, respectively. This study demonstrated that hawthorn extracts at 0.5% and 1% could mitigate HAA formation, especially at high cooking temperatures.

Interaction between Bioactive Carbonyl Compounds and Asparagine and Impact on Acrylamide

Acrylamide in heated foods is formed as a result of condensation of asparagine with a carbonyl source. Besides the most commonly known α-hydroxycarbonyl compounds such as fructose and glucose, glyoxal, methylglyoxal, 5-hydroxymethyl-2-furfural, and other sugar degradation products bearing carbonyl groups also contribute to acrylamide formation. In addition to these carbonyl compounds bioactive carbonyl compounds also participate in Maillard reaction yielding to acrylamide formation. Firstly, the role of bioactive carbonyl compounds in acrylamide formation, their efficiencies in converting asparagine into acrylamide, and the factors affecting their reactivities are described in this chapter. Competitiveness of bioactive carbonyl compounds with α-hydroxycarbonyl compounds is reviewed as well. Formation mechanism between bioactive carbonyl compounds and asparagine is explained and finally the way of limiting the reactivity of bioactive carbonyl compounds is mentioned. Among the bioactive carbonyl compounds, curcumin, ascorbic acid, dehydroascorbic acid, silymarin, vanillin, pyridoxal, and some carbonyls of virgin olive oil phenolic extracts are reviewed as precursors of acrylamide. Bioactive carbonyl compounds compete with α-hydroxycarbonyl compounds in reacting with asparagine, and the kinetic behavior of acrylamide formation depends on the reactivity of bioactive carbonyl compounds. Besides the chemical reactivity of carbonyl compounds, melting point is also an indicator in systems where the bioactive carbonyl and α-hydroxycarbonyl compounds are together.

CHAPTER 17:Adding Calcium to Foods and Effect on Acrylamide

Acrylamide is found in widely consumed heat-treated foods such as fried potato and bakery products. It is formed from asparagine via a Maillard reaction at temperatures higher than 100 °C. The presence of acrylamide has been considered as an important food-related crisis since it is classified as probably carcinogenic to humans. For this reason, acrylamide mitigation in foods becomes an important issue. Calcium salts are used to mitigate acrylamide formation in especially potato and bakery products. Calcium cation restricts asparagine to form a Schiff base during Maillard reaction in the presence of carbonyl compounds. There are several studies indicating the effect of calcium on mitigation of acrylamide both in model and food systems. According to these studies usage of calcium salts is found to be effective in mitigation of acrylamide formation. On the other hand, calcium salts cause increases in sugar dehydration products like 5-hydroxymethyl-2-furfural during heating. High solubility in water, effectiveness in low concentrations without changing sensorial properties and low price of calcium salts make them suitable in industrial applications.

Acrylamide: An Overview of the Chemistry and Occurrence in Foods

Thermal processing has great importance in foods in terms of microbiological safety and nutritional quality together with the desired sensory properties, e.g. color, texture and flavor, of fried, baked and roasted food products. But thermal process of foods does not only cause desirable changes, it also induces chemical reactions leading to form heat-induced toxic compounds, so-called thermal process contaminants, such as acrylamide. Acrylamide was discovered by the Swedish Authorities in 2002 in a wide range of fried and oven-cooked foods. Since it is classified as probably carcinogenic to humans (Group 2A) by the International Agency for Research on Cancer (IARC), acrylamide is considered as an important food safety problem by international authorities. Foods high in carbohydrates, such as potato chips, French fries, pan-fried potato products, biscuits, and crisp bread have been found to contain relatively high amount of acrylamide. The Maillard reaction has been reported to be the main formation pathway. Researchers have been developed many mitigation strategies for acrylamide formation based on the factors affecting its formation. This article discusses the formation chemistry and occurrence of acrylamide in foods, as well as the factors affecting its formation.