Gema Arribas-Lorenzo

Analysis, distribution, and dietary exposure of glyoxal and methylglyoxal in cookies and their relationship with other heat-induced contaminants

Thermal processing of food leads to the formation of dicarbonyls such as glyoxal (GO) and methylglyoxal (MGO), which are potentially harmful because they are precursors of advanced glycation end products (AGEs). GO and MGO formation was examined during the baking process of cookies as cookies are a widely distributed food commodity in Western diets. GO and MGO were chromatographically analyzed after employment of an improved method of derivatization with orthophenylenediamine to produce stable quinoxaline derivatives. Sample extraction, cleanup, and chromatographic conditions were evaluated to provide an in-house validated procedure for GO and MGO analysis in cookies. Quantification limits were set at 1.5 and 2 mg/kg for GO and MGO, respectively, with an average recovery of 103% and a calculated precision lower than 7%. Studies were carried out both on laboratory-scale cookies under controlled conditions and on commercial samples as well. GO and MGO values in commercial cookies ranged from 4.8 to 26.0 mg/kg and from 3.7 to 81.4 mg/kg, respectively. Commercial cookies made from ammonium bicarbonate and fructose showed the highest levels of MGO. Dicarbonyls were rapidly formed on the upper side of the cookie regardless of the shape or thickness of the samples, confirming there was a surface effect. Under controlled baking conditions, the formations of GO and MGO were linearly correlated with baking time. MGO formation was related with acrylamide, a heat-processing contaminant, in commercial cookies, but this relationship was not observed for 5-hydroxymethylfurfural. Dietary exposure of the Spanish population to GO and MGO from cookies was estimated to be 213 and 216 microg/person/day, respectively.

Estimation of dietary intake of 5-hydroxymethylfurfural and related substances from coffee to Spanish population

5-Hydroxymethylfurfural (HMF) is naturally formed during food processing or cooking activities, giving its ubiquity in the Western diet. HMF could be metabolised to 5-sulfooxymethylfurfural making HMF potentially harmful in an extent unknown at present. Coffee is the main exposure source. Occurrence of HMF, 5-hydroxymethyl-2-furoic acid (HMFA) and 2-furoic acid (FA) were measured in commercial ground coffee and soluble coffee marketed in Spain. Levels of 110, 625, 1734, 2480 mg HMF/kg were obtained for natural, blend, torrefacto and soluble coffee, respectively, giving four classes significantly different. Soluble coffee showed the largest variability in HMF. Levels of HMFA and FA did not change significantly being about 600 mg/kg. Dietary exposure to HMF coffee to consumption in the total Spanish population was estimated to be 8.57 mg/day by using a deterministic approach. However, median level was recalculated to 5.26 mg HMF/day when specific contribution of each type of ground and soluble coffee in the consumption habits was considered. Resultant value is above of the threshold of concern (1600 microg HMF/day, mTAMDI). A level of 8.57 mg HMF/day in persons with high consumption habits (95th percentile) was calculated for risk assessment.

Acrylamide content of selected Spanish foods: Survey of biscuits and bread derivatives

An overview of the acrylamide content in commercial biscuits and bread derivatives (bread sticks, bread crust, crackers) marketed in Spain is presented. Acrylamide was determined by stable isotope dilution LC–MS with an LOQ of 30 µg kg−1. Acrylamide content ranged from <LOQ–2085, <LOQ–151, <LOQ–296 and <LOQ–323 µg kg−1 for biscuits, crisp bread, crackers and bread sticks, respectively. Acrylamide was significantly higher in samples when ammonium hydrogen carbonate had been used as a rising agent and high fibre content (>5%) used in the formulation, but lower when functional ingredients, such as polyols, were used. An estimation of the acrylamide dietary exposure related to biscuits and bread derivatives was calculated as 0.082 µg kg−1 day−1. Estimated dietary intake were 0.002 and 0.058 µg kg−1 day−1 for crackers and biscuits, respectively.

Dietary exposure to acrylamide from potato crisps to the Spanish population

Potato crisps are one of the food commodities that contribute most to overall dietary human exposure of acrylamide. This investigation has estimated the dietary exposure to acrylamide form potato crisps in the Spanish population. Sampling of potato crisps (n = 36) from 16 different producers were carried out in March 2008. An average level of 740 µg kg−1 (ranging from 81 to 2622 µg kg−1; minimum to maximum) and a median of 592 µg kg−1 were obtained. Acrylamide levels in marketed potato crisps have been significantly reduced (nearly to 50%) compared with a previous sampling performed 4 years earlier. The observed signal value (90th percentile) was 1377 µg kg−1 with 86% of the samples with acrylamide levels lower than 1000 µg kg−1. Dietary exposure to acrylamide from potato crisp consumption in the total Spanish population was estimated to be 0.042 µg kg−1 body weight day−1 by using a deterministic approach based on the National consumption database. In a second study, dietary exposure (based on a 3-day food record) was determined to be 0.053 µg kg−1 body weight day−1 for the adult population (17–60 years) and 0.142 µg kg−1 body weight day−1 for children (7–12 years). The contribution of potato crisps to the estimated dietary acrylamide exposure of the Spanish population is moderate as compared with other European Member States.

Effect of pyridoxamine on acrylamide formation in a glucose/asparagine model system

The effect of pyridoxamine (PM) on the reduction of acrylamide (AA) formation in a low-moisture equimolar glucose/asparagine model system was investigated. Formation/elimination kinetics of acrylamide was carried out at temperatures between 120 and 180 degrees C. Time courses of glucose, asparagine, pyridoxamine, 3-aminopropionamide (3-APA), acrylamide, and browning were measured to get more insight on the mechanism of action of PM. PM exhibited an inhibitory effect on AA formation at all temperatures studied, but became more relevant at 160 and 180 degrees C (up to 51% reduction). Degradation rates of glucose and asparagine were not significantly affected by PM, but PM was rapidly consumed in the glucose/asparagine system. Browning was significantly suppressed by addition of PM in the system, and formation of 3-APA was increased as compared to control. In comparison with pyridoxal, pyridoxine, and ascorbic acid, PM exerted the highest inhibition activity against AA formation, and a clear dose-response was observed. The nucleophilic aminomethyl group of PM was crucial for the exertion of an inhibition effect more than double those other B6 vitamers. The action mechanism of PM was attributable to its structural features that have the capacity to scavenge intermediary dicarbonyls formed during sugar degradation and advanced stages of the Maillard reaction. These findings open new possibilities for strategies in acrylamide mitigation where formation of reactive dicarbonyls should be carefully considered.

The formation of potentially harmful compounds in churros, a Spanish fried-dough pastry, as influenced by deep frying conditions.

Colour, moisture, hydroxymethylfurfural (HMF) and acrylamide (AA) were investigated in traditional Spanish churros. Samples were deep-fried in sunflower oil at lab-scale temperatures of 180, 190 and 200°C and for frying times of 2, 3, 5 and 7min. Fresh made churros were also obtained from local producers. HMF ranged from 1.2±0.02 to 221.4±2.02mg/kg for lab-scale experiments and an average of 74.3±47.5mg/kg was recorded in commercial samples. AA ranged from below the limit of quantitation to 90±0.6μg/kg for lab-scale experiments and an average of 46±24.5μg/kg was measured in commercial samples. Temperatures between 185 and 200°C are commonly used to obtain churros with an acceptable palatability and a crispy surface. However, HMF and AA levels increased nearly two-fold from 190 to 200°C at the same frying times, indicating that a more precise control of frying temperatures is required to minimize their formation.

Recent Insights in Acrylamide as Carcinogen in Foodstuffs.

Abstract Acrylamide is a heat-induced contaminant naturally formed during home cooking and industrial processing of many foods consumed daily around the world. French fries, potato crisps, bread, cookies, and coffee exert the highest contribution to dietary exposure of acrylamide to humans. Furthermore, food safety international bodies and industrial sectors are very active for implementing strategies to minimize its formation during roasting, baking, frying, toasting, etc. Given the prevalence of acrylamide in the human diet and its toxicological effects, it is a general public health concern to determine the risk of dietary intake of acrylamide. However, associations between dietary acrylamide exposure and increase risk of different cancers are somewhat controversial and do not have a direct extrapolation to the global population. Accordingly, further long-term studies with a general view are ongoing to clarify the risk scenario and to improve the methodology to detect small increases in cancer incidence.