Lipid-derived aldehyde degradation under thermal conditions

Effect of Roasting and Storage on the Formation of Maillard Reaction and Sugar Degradation Products in Hazelnuts ( Corylus avellana L.)

This study investigated the effect of roasting (150 °C for 30 min) and storage (12 months at 4 °C, 25 °C, and 25 °C in vacuum package), conditions of which are generally applied in the industry and markets, on the formation of Maillard reaction and sugar degradation products, namely dicarbonyl compounds, 5-hydroxymethylfurfural, N-ε-fructosyllysine, and N-ε-carboxymethyllysine in Tombul and Levant hazelnuts. Roasting increased all dicarbonyl compounds significantly ( p < 0.05). The concentration of methylglyoxal was the highest while 1-deoxyglucosone was the lowest in roasted hazelnuts. 5-Hydroxymethylfurfural and N-ε-carboxymethyllysine also increased significantly ( p < 0.05) with roasting while furosine decreased. Roasting changed the progress of the Maillard reaction from the early stage to the advanced stage. On the other hand, there were no significant changes ( p > 0.05) in the concentration of Maillard reaction and sugar degradation products independent of the storage conditions or time and hazelnut variety, except for glyoxal, diacetyl, and 1-deoxyglucosone. Therefore, neither 5-hydroxymethylfurfural nor furosine is suggested as a storage marker of the Maillard reaction and sugar degradation.

Understanding the implications of current health trends on the aroma of wet and dry cured meat products

Meat product aroma is affected by various meat processing factors. In this review the main biochemical reactions involved in the development of meat product aroma (wet, dry cured and fermented) are fully described. Moreover, the different techniques used for key aroma elucidation in meat products are defined. The aroma compounds present in wet, dry cured and fermented meat products (sausage and whole piece) have been summarized. The mechanisms of aroma formation during the manufacture of cooked and dry/fermented meat products are described. In wet meat products the main reactions described are lipid degradation (oxidative reactions), Maillard reactions, Strecker degradation, and thiamine degradation while in dry meat products are; lipid degradation (oxidative reactions), thiamine degradation, microbial carbohydrate fermentation and microbial metabolism including complex interactions among them such as the amino acid degradation produced by lipid oxidation products. Finally, the effect of current health trends such as salt, fat and nitrifying content reduction on the development of meat product aroma is explained.

Carbonyl-Phenol Adducts: An Alternative Sink for Reactive and Potentially Toxic Lipid Oxidation Products

Different from the well-characterized function of phenolics as antioxidants, their function as lipid-derived carbonyl scavengers is mostly unknown. However, phenolics react with lipid-derived carbonyls as a function of the nucleophilicity of their reactive groups and the electronic effects and steric hindrances present in the reactive carbonyls. Furthermore, the reaction produces a wide variety of carbonyl-phenol adducts, some of which are stable and have been isolated and characterized but others polymerize spontaneously. This perspective updates present knowledge about the lipid-derived carbonyl trapping ability of phenolics, its competition with carbonyl-amine reactions produced in foods, and the presence of carbonyl-phenol adducts in food products.

Effect of rosmarinic acid and carnosic acid on AGEs formation in vitro

This work aimed to investigate the effect of the two main components of rosemary extracts, namely rosmarinic acid (RA) and carnosic acid (CA), on the formation of advanced glycation end-products (AGEs) in vitro. In the bovine serum albumin (BSA)/glucose model, addition of RA and CA at 400μg/mL inhibited fluorescent AGEs by more than 90%, and carboxymethyl lysine (CML) and carboxyethyl lysine (CEL) by 82.7% and 75.2%, and 71.4% and 64.2%, respectively. Moreover, the addition of RA and CA at 400μg/mL inhibited fluorescent AGEs by more than 90% both in the BSA/glyoxal (GO) and BSA/methylglyoxal (MGO) models, the formation of CML by 64.9% and 53.9% in BSA/GO model, and CEL by 28.9% and 24.3% in BSA/MGO model, respectively. RA and CA also significantly decreased the concentration of MGO and protein carbonylation.

Consumer Acceptability of Intramuscular Fat

Fat in meat greatly improves eating quality, yet many consumers avoid visible fat, mainly because of health concerns. Generations of consumers, especially in the English-speaking world, have been convinced by health authorities that animal fat, particularly saturated or solid fat, should be reduced or avoided to maintain a healthy diet. Decades of negative messages regarding animal fats has resulted in general avoidance of fatty cuts of meat. Paradoxically, low fat or lean meat tends to have poor eating quality and flavor and low consumer acceptability. The failure of low-fat high-carbohydrate diets to curb "globesity" has prompted many experts to re-evaluate of the place of fat in human diets, including animal fat. Attitudes towards fat vary dramatically between and within cultures. Previous generations of humans sought out fatty cuts of meat for their superior sensory properties. Many consumers in East and Southeast Asia have traditionally valued more fatty meat cuts. As nutritional messages around dietary fat change, there is evidence that attitudes towards animal fat are changing and many consumers are rediscovering and embracing fattier cuts of meat, including marbled beef. The present work provides a short overview of the unique sensory characteristics of marbled beef and changing consumer preferences for fat in meat in general.

Flavoring Compounds Dominate Toxic Aldehyde Production during E-Cigarette Vaping

The growing popularity of electronic cigarettes (e-cigarettes) raises concerns about the possibility of adverse health effects to primary users and people exposed to e-cigarette vapors. E-Cigarettes offer a very wide variety of flavors, which is one of the main factors that attract new, especially young, users. How flavoring compounds in e-cigarette liquids affect the chemical composition and toxicity of e-cigarette vapors is practically unknown. Although e-cigarettes are marketed as safer alternatives to traditional cigarettes, several studies have demonstrated formation of toxic aldehydes in e-cigarette vapors during vaping. So far, aldehyde formation has been attributed to thermal decomposition of the main components of e-cigarette e-liquids (propylene glycol and glycerol), while the role of flavoring compounds has been ignored. In this study, we have measured several toxic aldehydes produced by three popular brands of e-cigarettes with flavored and unflavored e-liquids. We show that, within the tested e-cigarette brands, thermal decomposition of flavoring compounds dominates formation of aldehydes during vaping, producing levels that exceed occupational safety standards. Production of aldehydes was found to be exponentially dependent on concentration of flavoring compounds. These findings stress the need for a further, thorough investigation of the effect of flavoring compounds on the toxicity of e-cigarettes.

Sensory and Flavor Chemistry Characteristics of Australian Beef: Influence of Intramuscular Fat, Feed, and Breed

The sensory attributes and flavor chemistry of grilled beef striploins (M. longissimus lumborum, n = 42) varying widely in marbling from commercial production types typical for Southern Australia were extensively characterized. Striploins from Angus grass-fed yearlings (5.2-9.9% intramuscular fat), Angus grain-finished steers (10.2-14.9%), and Wagyu grass-fed heifers (7.8-17.5%) were evaluated. Inherent differences between samples from grass- and grain-fed Angus cattle were minimal when the intramuscular fat content was above ∼5%. After adjusting for intramuscular fat, Wagyu samples had more intense flavor and higher tenderness and juiciness compared to Angus grass-fed samples. Grilled beef flavor, dairy fat, and sweetness increased with the marbling level, and sourness and astringency decreased. Tenderness and juiciness increased with the marbling level and were correlated with Warner-Bratzler peak force measurements. Trained panel sensory differences in flavor corresponded with increases in aroma volatiles and changes in nonvolatile flavor compounds. Unsaturated fatty acids with potential health benefits (vaccenic, oleic, and rumenic acids) increased with the level of marbling.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation and fate: an example of the coordinate contribution of lipid oxidation and Maillard reaction to the production and elimination of processing-related food toxicants

Major chemical reactions dealing with carbonyl chemistry in foods (Maillard reaction and lipid oxidation) play a role in PhIP formation and fate, pointing to this and analogous heterocyclic aromatic amines as outcomes of this chemistry.