How much reducing sugar may potatoes contain to avoid excessive acrylamide formation during roasting and baking?

For many consumers, potatoes fried or roasted in professional or private kitchens are the most important source of exposure to acrylamide. Acrylamide formation can be reduced by appropriate preparation techniques, but suitable potatoes are a prerequisite. The tendency of potato to form acrylamide can be approximated by the content of reducing sugar. Roast potatoes (hash browns, Rösti) and oven-fried potatoes (Bratkartoffeln) were prepared to optimum culinary quality regarding crispiness and then evaluated in terms of browning, roasting flavor and acrylamide content. Preparation procedures were optimized to produce a minimum of acrylamide. It is concluded that potatoes with less than 0.2 g/kg fresh weight fructose and glucose are not suitable for roasting (insufficient browning and flavor), while roasted products of minimum crispiness prepared from potatoes with more than 1 g/kg reducing sugar contain more than 500 µg/kg acrylamide. It is proposed that potatoes which may be used for roasting and frying should contain less than 1 g/kg fresh weight of reducing sugar. This can easily be fulfilled with the most important potato cultivars grown in Switzerland, but presupposes that potatoes are no longer stored at 4 °C.     

Determination of acrylamide in roasted chestnuts and chestnut-based foods by isotope dilution HPLC-MS/MS

A collaboratively trial tested isotope dilution liquid chromatographic method with positive electrospray ionisation tandem mass spectrometry for the analysis of acrylamide in bakery ware and potato products has been extended to the determination of acrylamide in roasted chestnuts and chestnut-based foods. As chestnuts have a similar composition to potatoes, considerable amounts of acrylamide can be expected, especially in roasted chestnut products. This paper presents the concentrations of acrylamide in 31 different chestnut samples (fresh, roasted, flour, cooked, glazed) that were collected in nine European countries during 2005/2006. The influence of the roasting time on the acrylamide content was also experimentally investigated. A test portion was extracted after homogenisation with water and isotopically labelled acrylamide was added. The extract was centrifuged and the supernatant was cleaned-up in two consecutive solid phase extraction steps. The final extract was analysed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). An HPLC column based on graphitised carbon was applied for chromatographic separation. Acrylamide concentrations in purchased roasted chestnuts were in the range of <8–1278 μg/kg whereas only low amounts (<4–159 μg/kg) were found in chestnut products. However, the median acrylamide content of the commercial roasted chestnut samples was 90 μg/kg. The influence of the roasting time on the acrylamide content in roasted chestnuts was evaluated too. As with roasted and fried potato products, the roasting time has a significant influence on the acrylamide formation. Therefore, the consumers might be exposed to significant amounts of acrylamide by eating roasted chestnuts, especially when a batch remains in the roasting vessel for too long time.     

Acrylamide formation in low-fat potato snacks and its correlation with colour development.

A recipe and technological process for the production of low-fat potato snacks (7% fat) was developed at the Institute of Food Technology of Plant Origin (Agricultural University of Poznan) using a combination of extrusion and a roasting process. Due to the character of the product, the level of acrylamide was analysed. At the same time, the influence of temperature and time of heating on acrylamide levels were monitored, as well as the correlation between colour development and acrylamide content. The level of acrylamide in low-fat potato snacks was 489 +/- 26 microg kg(-1), which is comparable to French fries, crackers and cookies but almost three times less than in potato chips, as analysed by other authors. It was also shown that temperature and heating time have a significant influence on acrylamide formation, with temperature having a stronger effect than time. Measurement of colour and acrylamide content at different temperatures and roasting times showed that there is a substantial correlation between lightness (L*), redness (a*), yellowness (b*) and acrylamide concentration as a function of time: r(2) = -0.995, r(2) = 0.996, r(2) = 0.998, respectively. Graduated increases in roasting temperature showed a correlation between lightness (L*) or redness (a*) and acrylamide concentration: r(2) = -0.947 and r(2) = 0.968. Yellowness (b*) was not correlated with acrylamide content as a function of temperature.     

Influences of superheated steaming and roasting on the quality and antioxidant activity of cooked sweet potatoes

Roasted sweet potato is a popular food because of the attractive aroma produced by the Maillard reaction. However, the roasting process may lead to charred skin. Cooking with superheated (saturated) steam provides a solution to this problem. As the results show, when comparing sweet potatoes cooked by superheated steam, and those roasted for 40 min, respectively, the degree of gelatinisation could reach as high as 95% with only 140 °C superheated steam, while roasting required temperatures up to 240 °C. Moreover, in appearance, the skins of the sweet potatoes cooked using superheated steam were not charred like the roasted ones. However, sweet potatoes roasted at 240 °C for 60 min had the highest overall sensory score. When comparing the antioxidant activity, the sweet potatoes cooked by superheated steam had the highest content of total phenol and flavonoids, the best scavenging ability of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and the highest ferric‐reducing ability of plasma (FRAP).     

Dietary acrylamide exposure among Finnish adults and children: the potential effect of reduction measures

A deterministic exposure assessment using the Nusser method that adjusts for within-subject variation and for nuisance effects among Finnish children and adults was carried out. The food consumption data covered 2038 adults (25-74 years old) and 1514 children of 1, 3 and 6 years of age, with the data on foods' acrylamide content obtained from published Finnish studies. We found that acrylamide exposure was highest among the 3-year-old children (median = 1.01 μg kg(-1) bw day(-1), 97.5th percentile = 1.95 μg kg(-1) bw day(-1)) and lowest among 65-74-year-old women (median = 0.31 μg kg(-1) bw day(-1), 97.5th percentile = 0.69 μg kg(-1) bw day(-1)). Among adults, the most important source of acrylamide exposure was coffee, followed by casseroles rich in starch, then rye bread. Among children, the most important sources were casseroles rich in starch and then biscuits and, finally, chips and other fried potatoes. Replacing lightly roasted coffee with dark-roasted, swapping sweet wheat buns for biscuits, and decreasing the acrylamide content of starch-based casseroles and rye bread by 50% would result in a 50% decrease in acrylamide exposure in adults. Among children, substituting boiled potatoes for chips and other friend potatoes and replacing biscuits with sweet wheat buns while lowering the acrylamide content of starch-based casseroles by 50% would lead to acrylamide exposure that is only half of the original exposure. In conclusions, dietary modifications could have a large impact in decreasing acrylamide exposure.     

不同类型甘薯最佳烹饪方式评价

本研究通过评价甘薯不同食用方式下食味品质,明确不同鲜食品种的最佳食用方式及其与各品质指标的相关性。以干率、蛋白质、淀粉含量均较低的两个品种冀粉2号、烟薯25和干率、淀粉、蛋白质含量均较高的两个品种冀薯8号、冀元1号为材料,选择2种烹饪方式（烤制和蒸制）对薯块进行处理,采用感官评价、TPA测试、气相色谱-质谱联用（GC-MC）等方式对烤制和蒸制甘薯的口感、质构和香味成分进行测定分析。结果表明：薯块硬度、弹性、粘附性、咀嚼性、胶粘性在两种食用方式之间差异较大。相关性分析：干率与烤和蒸薯的内聚性、咀嚼性呈正相关;与淀粉、还原糖、可溶性糖呈负相关;蛋白质与烤和蒸薯的硬度、内聚性、胶粘性、咀嚼性呈正相关;与淀粉、还原糖、可溶性糖、烤和蒸薯的回复性呈负相关;淀粉与还原糖、可溶性糖、烤和蒸薯的弹性、回复性呈正相关;烤和蒸薯的咀嚼性、胶粘性呈负相关;还原糖与可溶性糖、烤和蒸薯的弹性呈正相关;与烤和蒸薯的硬度、咀嚼性 、胶粘性呈负相关;营养特性与质地指标具有一定的相关性。薯块烤制和蒸制共检测出49种香气物质,冀粉2号、冀薯8号香味物质烤制比蒸制分别多11、8种,冀元1号、烟薯25香味物质烤制比蒸制分别少3、1种;感官评价得出冀粉2号、烟薯25烤制口感比蒸制口感好;冀薯8号、冀元1号蒸制口感比烤制好。综合得出：干率、蛋白质含、淀粉含量均较低品种冀粉2号、烟薯25适合烤制;干率、蛋白质、淀粉含量均较高品种冀薯8号、冀元1号适合蒸制。     

Studies on acrylamide levels in roasting, storage and brewing of coffee

The content of acrylamide in coffee reaches a peak early in the roasting process, reflecting occurrence of both formation and destruction of acrylamide during roasting. Levels of acrylamide in the fully roasted product are a small fraction of the peak reached earlier. Glucose and moisture in green coffee do not show a significant correlation with acrylamide in roasted coffee. Pre-roasting levels of asparagine show a correlation only in Arabica coffee. The main factors affecting the level of acrylamide in roasted coffee appear to be the Arabica/Robusta ratio, with Robusta giving higher levels; time and degree of roast, with both shorter and lighter roasting at the edges of the normal roasting range giving higher levels; storage condition and time, with clear reduction at ambient storage. This storage reduction of acrylamide followed second order reaction kinetics with an activation energy of 73 KJ/mole. The acrylamide in roasted coffee is largely extracted into the brew and stable within usual time of consumption. As these four main factors also substantially affect the sensorial characteristics of the brew, and as modifications of the process have to comply with the consumer-accepted boundaries of taste profiles, only small effects on the acrylamide level are expected to be achievable.     

响应面法优化小龙虾烤箱辅助烤制工艺

以小龙虾为研究对象,探讨烤箱烤制小龙虾的加工工艺,以腌制时间、腌制液盐含量、烤制温度和烤制时间为单因素影响因子,小龙虾的感官评分和弹性为响应值,进行响应面优化分析。然后对烤制小龙虾的营养成分和风味特征进行测定和分析,并以鲜虾和水煮虾作为对照。结果表明：经优化后的小龙虾腌制时间为30 min、腌制液盐含量12 g/100 mL、烤制温度180℃、烤制时间20 min,在此工艺条件下小龙虾的感官评分为9.08分、弹性为3.88 mm,与预测值接近,表明该烤制工艺合理有效;烤制处理条件下单不饱和脂肪酸和多不饱和脂肪酸总含量显著高于鲜虾和水煮虾;烤制之后的小龙虾必需氨基酸和风味氨基酸含量较鲜虾和水煮虾差异明显,主要表现在天冬氨酸、甘氨酸、精氨酸和亮氨酸的损失,其中精氨酸损失最大;电子舌传感器上的烤虾响应值鲜度、咸味和甜味均显著高于鲜虾和水煮虾。适当的烤制有利于虾肉营养物质的保存和鲜香味的挥发,同时有利于产品营养与风味的提高。     

油炸马铃薯食品中发现丙烯酰胺的研究近况

对油炸或焙烤马铃薯食品中的丙烯酰胺含量、食品中丙烯酰胺含量的分析方法、丙烯酰胺毒性问题的最新研究结果进行了综述。现有研究结果表明 ,炸薯片、炸薯条中含有较高含量的丙烯酰胺 ,过度油炸会进一步增加薯条中的丙烯酰胺含量 ,而相应的生马铃薯原料与煮熟马铃薯中则不含丙烯酰胺。食品中丙烯酰胺含量的分析方法目前采用气相色谱 -质谱法 (GC MS)与液相色谱 串联质谱联用新技术 (LC/MS/MS) ,但食品中丙烯酰胺含量的分析方法、丙烯酰胺的毒理学研究仍在进一步发展中。     

Effect of Microwave Frying on Acrylamide Generation,Mass Transfer,Color, and Texture in French Fries

The objective of this work was to evaluate the effect of microwave power on acrylamide generation, as well as moisture and oil fluxes and quality attributes of microwave-fried potatoes. Concretely, 25 g of potato strips, in 250 mL of fresh oil (at room temperature), were subjected to three different microwave powers (315, 430, and 600 W) in a conventional microwave oven. Microwave frying resulted in an acrylamide reduction ranged from 37 to 83% compared to deep-oil frying. Microwave-fried French fries presented lower moisture and higher fat content than deep-oil fried potatoes. Concretely, microwave-fried potatoes presented values of moisture and texture more similar to potato chips than French fries, nonetheless with lower fat levels (less than 20 g/100 g wb) and acrylamide content (lower than 100 μg/kg wb) at the reference time. This study presents an alternative way of frying to address the production of healthier potato chips.     

An experimental set-up for studying acrylamide formation in potato crisps

The objective of this work was to set up lab-scale equipment for production of crisps mimicking industrial conditions. Slices of Saturna potatoes were deep-fat fried for 2-4.5 min at 160 °C. A solid phase extraction method for acrylamide from potato crisps was used, and the extraction recovery was calculated to 95%. Acrylamide was analysed using liquid chromatography tandem mass spectrometry. The relative standard deviation was below 3% for analyses performed on the same day and below 5% for inter-day analyses. The limit of quantification was estimated to be 160 μg/kg potato crisps. The colour of potato slices was determined using a digital imaging method and related to the acrylamide content. There were tendencies that L*(lightness) decreased and that that a*(redness) and b*(yellowness) increased with increasing acrylamide content. In another experiment, potatoes with different glucose levels were fried for 4 min but no significant difference in acrylamide content (2200-2800 μg/kg) was observed. The experiment was repeated after three months of storage. The levels of acrylamide increased significantly to 8200-13200 μg/kg. The potatoes had been fertilized with different levels of nitrogen, but no relation was found between the nitrogen supplied and the acrylamide content. The experimental set-up was shown to give realistic and reproducible experimental data, regarding colour, water content and acrylamide levels. It will be used together with the analytical methods as a platform for further research on the formation of acrylamide.     

Analysis of acrylamide by LC-MS/MS and GC-MS in processed Japanese foods.

Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was <5 and <15% for the LC-MS/MS and GC-MS methods, respectively. High correlation (r(2) - 0.946) was observed between values obtained by the two methods. Most potato crisps and whole potato-based fried snacks showed acrylamide concentrations >1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (<50 microg x kg(-1)) suggesting the formation of acrylamide is strongly influenced by processing conditions. Acrylamide concentrations in instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.     

Influence of microwave,the combined microwave/hot air and only hot air roasting on the formation of heat-induced contaminants of carob powders

ABSTRACT

This study aims to investigate the effects of microwave, combined microwave/hot air treatment and hot air-only roasting on the formation of heat-induced contaminants of carob powders. Moisture content, water activity and pH values of the product decreased with the increasing roasting time and microwave power, while browning index (BI) and ultraviolet absorbance (UV-A) values were increased. While L and b values of carob powders decreased with increasing the roasting time and microwave power, a and ΔE values were increased. Varying roasting conditions also significantly affected the content of Maillard reaction products (MRPs): 5-hydroxymethylfurfural (HMF) (0.69–28.32 mg/kg dry matter), furfural (<LOD-10.44 mg/kg dm), furan (6.65–10.26 mg/kg dm) and acrylamide (78.69–122.87 µg/kg dm). MRPs contents increased with increasing the roasting time and microwave power. The highest MRPs were found in the samples roasted at 140°C for 20 min by hot air. Significant correlations between the amount of MRPs and colour values were found, especially with a and b values.     

Influence of roasting conditions on the acrylamide content and the color of roasted almonds

ABSTRACT:  The influence of roasting conditions on the acrylamide content and on the color of roasted almonds of 3 cultivars was investigated. The temperature inside the almond kernel, the water content, the color, and the acrylamide content were determined at different roasting temperatures and times. The formation of acrylamide started only when the kernel temperature had exceeded approximately 130 °C. The activation energy for the acrylamide formation during the roasting of almonds was 123 kJ·mol⁻¹. The color as measured by the degree of brightness correlated well with the acrylamide content as acrylamide content increased with increasing darkness. Therefore, control of roasting temperature presents the critical factor for limiting the acrylamide concentration in the final product. At constant roasting conditions, almonds with higher initial moisture content contained less acrylamide after roasting, which is probably due to the influence of moisture on the development product temperature during roasting.     

Acrylamide content in fried chips prepared from irradiated and non-irradiated stored potatoes

The content of reducing sugars and asparagine, responsible for the formation of acrylamide, was determined in eight Indian potato varieties. Among these, Kufri chipsona-2 and Kufri lavkar showed the lowest level of reducing sugar (680.68 ± 56.50 mg/kg) and asparagine (2074.36 ± 122.27 mg/kg), respectively. The acrylamide content in potato chips prepared from Kufri chipsona-2, the variety that is used commercially in India for making potato chips was also the lowest. Irradiation of this variety of potatoes at the sprout inhibition dose of 60 Gy and subsequent storage for six months showed a 10.7% lower content of reducing sugars at both 14 and 4 °C. The acrylamide content was 8.41% and 6.95% lower in chips from irradiated potatoes stored at 14 and 4 °C than the corresponding non-irradiated controls. The colour of the chips was also better in irradiated potatoes as judged from the L∗ and a∗ values.     

Acrylamide in almond products

Acrylamide was determined in 86 different almond products, such as roasted almonds, almond-containing bakery products, raw almonds, and marzipan. The highest acrylamide concentrations were found in dark roasted almonds, while only moderate acrylamide contents were determined in bakery products. Roasting experiments under different process conditions showed that acrylamide increases with time and that temperature has a much stronger effect on acrylamide formation than time. During roasting reducing sugars are consumed faster and to a larger extent than free asparagine, suggesting that the content of reducing sugars may be a critical factor for acrylamide formation in roasted almonds. Acrylamide was found to decrease in roasted almonds during storage at room temperature.     

Reduction of Acrylamide Formation in Potato Chips by Low-temperature Vacuum Frying

ABSTRACT: Potatoes and other foods that have a high content of the amino acid asparagine and a high accumulation of reducing sugars are subject to the formation of acrylamide upon frying. The objectives of this research were (1) to analyze the level of acrylamide formed during deep-fat frying of potato chips and (2) to evaluate means of reducing acrylamide in potato chips by using different potato cultivars and vacuum frying. Several potato cultivars were used in this research, including Innovator (I), NDTX 4930–5W (N), ATX 854 04–8W (ATw), Atlantic (A), Shepody (S), ATX847806–2Ru (ATr), and White-Rose (W). An electric bench-top (atmospheric conditions)-type fryer was used to fry the potatoes. Three temperatures were used: 150 °C, 165 °C, and 180 °C. The vacuum frying experiments were performed at 118 °C, 125 °C, and 140 °C and a vacuum pressure of 10 Torr. The potatoes were sliced (1.5-mm thick) and fried for different lengths of times. For potatoes fried at 165 °C (for 4 min) at atmospheric conditions, the acrylamide contents were 5021 ± 55 ppb (W), 552 ± 25 ppb (I), 358 ± 50 ppb (N), 397 ± 25 ppb (ATw), 646 ± 55 ppb (A), 466 ± 15 ppb(S), and 537 ± 14 ppb (ATr). Vacuum frying reduced acrylamide formation by 94%. Results showed that both cultivar and modified frying systems can play an important role in reducing acrylamide formation in fried potatoes. As the frying temperature decreased from 180 °C to 165 °C, acrylamide content in potato chips reduced by 51% during traditional frying and by 63% as the temperature decreased from 140 °C to 125 °C in vacuum frying. Increased frying time increased acrylamide formation during traditional frying for all temperatures and frying methods analyzed. However, the effect on acrylamide concentration was greater for the traditional frying than the vacuum frying. Keywords: acrylamide, vacuum, frying, potato, temperature     

热烫预处理降低鲜切油炸薯片中丙烯酰胺的工艺优化研究

研究热烫预处理对鲜切油炸薯片中丙烯酰胺的影响和薯片油炸工艺优化。在相同条件下,分别对原料进行热烫和非热烫处理,在不同油炸温度和时间条件下进行油炸试验,采用DNS法测还原糖,液质联用法检测薯片中丙烯酰胺含量。结果表明,通过对切片的马铃薯进行热烫处理,即75℃热烫150s,能明显降低还原糖含量,160℃油炸120s,可降低丙烯酰胺含量至67.18μg/kg。     

Formation of 5-hydroxymethyl-2-furfural (HMF) and 5-hydroxymethyl-2-furoic acid during roasting of coffee

The formation of 5-hydroxymethyl-2-furfural (HMF) and 5-hydroxymethyl-2-furoic acid (HMFA) during roasting of coffee was studied. At 240 degrees C the maximum concentration of HMF occurs after 3 min with a quick degradation up to 10 min when most of the HMF has disappeared again. Similar to 5-hydroxymethyl-furfural, HMFA is formed in coffee but not in a model system consisting of sucrose, alanine with or without chlorogenic acid. It was shown that HMFA is produced from different precursors than HMF namely glyceraldehyde and pyruvate. The comparison of the laboratory scale roasting with industrial roasting showed that 5-hydroxymethyl-furfural decreases with a higher degree of roasting whereas HMFA did not change. In the laboratory scale experiments, the highest concentration of 5-hydroxymethyl-furfural in coffee (909 microg/g) was obtained after 3 min and the maximum concentration of HMFA after 4 min (150 microg/g). Industrially roasted coffee contained up to 350 microg/g 5-hydroxymethyl-furfural and 140 microg/g HMFA.     

Correlation Between the Stability of Chlorogenic Acids,Antioxidant Activity and Acrylamide Content in Coffee Beans Roasted in Different Conditions

The aim of this study was to determine the effect of different roasting conditions, including temperature, humidity, and roasting air velocity on acrylamide contents in roasted Robusta coffee. In addition, acrylamide concentrations were correlated with the degradation of coffee bean polyphenols and its antioxidant activity. In the process of roasting in a quarter-technological scale apparatus used temperatures ranged from 190 to 216°C. Dry or moist air at a velocity of 0.5 or 1 m s^?1 was used. Beans were roasted to achieve optimal sensory properties. The increase of roasting air velocity regardless of its temperature resulted in the intensification of acrylamide formation. The increase of humidity of roasting air caused a reduction of acrylamide formation, but only at the highest used roasting temperature. However, the modification of roasting conditions to achieve a drop in acrylamide concentration resulted in increased degradation of polyphenols and/or deterioration of antioxidant activity. The optimal roasting parameters were: Temperature 203°C, dry air, and low velocity of roasting air. Under these conditions, the roasted beans were characterized by relatively low level of acrylamide and moderate degradation of polyphenols.