Tea Polyphenols as Inhibitors of Furan Formed in the Maillard Model System and Canned Coffee Model

In this article, the effects of sugars and amino acids on furan formation via the Maillard reaction in low‐moisture model systems were investigated. Glucose and alanine are important furan precursors, and the effects of the heating temperature, heating time, and molar ratio of glucose to alanine on furan formation were studied in glucose/alanine model system by response surface methodology. The heating temperature greatly affected furan formation. The maximum furan concentration was obtained with a glucose‐to‐alanine molar ratio of 0.83:1.00, by heating at 151 °C for 41 min. Tea polyphenols effectively inhibited furan formation in the glucose/alanine model and a canned coffee model. A high inhibition rate of 42.4% ± 1.5% was obtained in the canned coffee model during sterilization procedure with addition of 84 mg (the mass fraction is 12.1%) of tea polyphenols (99%). However, the content of aromatic components in the canned coffee model was significantly reduced at the same time. This study provides evidence for a good furan inhibitor that can be used in food processing.     

Furan in commercial baby foods from the Spanish market: estimation of daily intake and risk assessment

ABSTRACT

The occurrence of furan in commercial baby food samples from the Spanish market was evaluated using an automated headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS). A total of 76 baby food samples including infant formula, baby cereals, fruit in cans and/or jars, vegetables, meat, and fish, were surveyed for furan content. The lowest concentration of this compound was found in infant formula (<0.02–0.33 ng ml^?1), and cereal-based food (0.15–2.1 ng g^?1) while baby food containing fish showed the highest concentrations (19–84 ng g^?1). Following recommendation of the European Food Safety Authority (EFSA), the effect on furan content was evaluated of consumer home preparation of foods, heating and handling. Furan concentrations were reduced by up to 35% when samples were heated in a dish using microwave oven and by up to 53% when a hot water bath was used. Finally, we estimated the furan intake from baby food consumption (0.002–1.18 µg kg^?1 body weight day^?1) and we calculated the margin of exposure (MOE) from samples as purchased and also after home preparation of the food. For infant formula and cereal baby foods, the MOEs (26,278–412,776) indicated no infant health concern or priority, while for meat and fish-based baby foods the values pointed to a potential public health risk, even considering the furan losses during preparation at home.     

Effect of home and industrial processing on protein quality of baby foods and breakfast cereals.

The effect of home and industrial processing on the protein quality of baby foods and breakfast cereals, commonly consumed in Pakistan, was studied. The nutritive value of baby foods and breakfast cereals was determined chemically (including amino acid analyses) and biologically in N-balance experiments with growing rats. Lysine and threonine were found to be the limiting amino acids in home and industrially produced baby foods whereas lysine was the limiting amino acid in all the breakfast cereals. The lysine contents of home-prepared baby foods were damaged to a great extent at 150–160°C compared with 100–110°C. The levels of lysine (35–76%) and arginine (10–41%) were in all the breakfast cereals reduced by the industrial processing. The net protein utilisation (NPU) of home-prepared baby foods ranged from 51–81% as compared to 57–60% for industrially produced baby foods. The net dietary protein calorie per cent (NDp cal%) of home and industrially produced baby foods varied between 2.6 and 7.3% and between 7.0 and 7.1% respectively. The industrial processing reduced significantly the true digestibility (4–20%), biological value (13–34%) and net protein utilisation (17–41%) of all the breakfast cereals.     

Survey of furan in foods and coffees from five European Union countries

Canned and jarred baby foods (74), canned and jarred adult foods (63) and 70 coffees sold in Belgium, Italy, Portugal, Spain and The Netherlands were analysed for their furan content using a validated automated headspace GC–MS procedure. Seven balsamic vinegars from Italy and Spain were also analysed. All 74 baby food samples contained detectable furan, with an average level of 37 ng/g. A total of 54 of 63 canned and jarred foods contained detectable furan with an average level of 24 ng/g. Levels of furan in coffee as consumed were very variable and reflected different preparation methods and coffee strengths. Over 50% of Italian samples contained more than 200 ng/g, whereas over 20% of Belgian coffees contained less than 21 ng/g furan. Some brews made from fine grained coffee contained much more furan than did brews made from normal or coarse grained coffee. Although furan was low in most instant coffees, two Italian products “instant espresso” and “instant mocha” contained about 150 ng/g furan. Balsamic vinegars from Spain contained 159–662 ng/g of furan; however, other samples from Spain and Italy contained only 6–25 ng/g.     

Analysis of furan in heat-processed foods consumed in Korea using solid phase microextraction–gas chromatography/mass spectrometry (SPME–GC/MS)

Furan (C₄H₄O) is a volatile compound formed during the Maillard reaction and was recently classified as a possible human carcinogen (group 2B) by the International Agency for Research on Cancer. It has been reported to occur in various canned and jarred foods that undergo heat treatment. The aim of the present study was to optimise the sample preparation for furan analysis using solid phase microextraction–gas chromatography/mass spectrometry (SPME–GC/MS), according to the food matrix. We also performed the monitoring and risk assessment of furan in various food products. The optimised fibre exposure temperatures, time and amount of sample of liquid, semi solid and paste state foods were 5 g (ml), 50 °C, and 20 min, respectively. The level of furan in canned meat (32.16 ng/g) was the highest among the samples studied. The furan levels in canned fish, canned vegetable, nutritional/diet drinks, canned soups and jarred sauces were 29.40, 22.86, 7.28, 18.54 and 21.52 ng/g, respectively. Furan concentrations in baby food products were between 3.43 and 97.21 ng/g. Exposure estimates (14.59 ng/kg bw/day) of baby foods was the highest among all the tested food samples. However, the exposure estimate of baby foods was lower than that prescribed by the US FDA.     

Ohmic heating: A promising technology to reduce furan formation in sterilized vegetable and vegetable/meat baby foods

Occurrence of furan, classified as carcinogen 2B by the International Agency for Research on Cancer, in heat-processed foods, especially sterilized baby foods, is of a health concern. On this account, innovative processing practices ensuring microbial safety, acceptable sensorial features, and, at the same time, minimizing furan formation have to be searched. In this study, the potential of ohmic heating to mitigate furan formation was demonstrated. Compared to conventional retort sterilization, significant mitigation (70–90%) of furan was achieved, assumingly due to reduced degradation of furan precursor under faster terms heating conditions. In purees containing meat, approx. two times less furan was formed, regardless of the processing technology. In addition to furan, also other headspace volatiles were measured and statistically evaluated. Compounds originated through fatty acids oxidation and Maillard reaction products were more abundant in conventionally sterilized samples compared to those treated by ohmic heating.Industrial relevanceOhmic heating is an emerging technology being employed in the field of food processing which applies a direct electric current to food products, providing rapid and uniform heating throughout the product. Shorter heating times used in ohmic heating, as compared to conventional retort sterilization, reduce potential losses of valuable nutrients and as well as reduce the formation of undesirable processing contaminants, in particular furan.The presented work examines furan concentrations across various stages of baby food production, in order to compare ohmic heating and retort sterilization processes. Volatile compound fingerprints for baby food purees processed via both sterilization methods, both prior and post sterilization were assessed. The results presented in this work are of high potential interest to the baby food industry to reduce both heat induced chemical changes and exposure of infants and babies to hazardous processing contaminants such as furan.     

Formation of furan in baby food products: Identification and technical challenges

Furan is generally produced during thermal processing of various foods including baked, fried, and roasted food items such as cereal products, coffee, canned, and jarred prepared foods as well as in baby foods. Furan is a toxic and carcinogenic compound to humans and may be a vital hazard to infants and babies. Furan could be formed in foods through thermal degradation of carbohydrates, dissociation of amino acids, and oxidation of polyunsaturated fatty acids. The detection of furan in food products is difficult due to its high volatility and low molecular weight. Headspace solid-phase microextraction coupled with gas chromatography/mass spectrometer (GC/MS) is generally used for analysis of furan in food samples. The risk assessment of furan can be characterized using margin of exposure approach (MOE). Conventional strategies including cooking in open vessels, reheating of commercially processed foods with stirring, and physical removal using vacuum treatment have remained unsuccessful for the removal of furan due to the complex production mechanisms and possible precursors of furan. The innovative food-processing technologies such as high-pressure processing (HPP), high-pressure thermal sterilization (HPTS), and Ohmic heating have been adapted for the reduction of furan levels in baby foods. But in recent years, only HPP has gained interest due to successful reduction of furan because of its nonthermal mechanism. HPP-treated baby food products are commercially available from different food companies. This review summarizes the mechanism involved in the formation of furan in foods, its toxicity, and identification in infant foods and presents a solution for limiting its formation, occurrence, and retention using novel strategies.     

Some factors affecting the formation of furan in heated foods

Levels of furan in various foods were measured before and after heating under heating and laboratory conditions. The effect of contact with can coatings, sealing gaskets and the epoxidized oils used in gasket manufacture on furan formation was studied. The objective was to identify factors affecting furan formation. Furan present in heat-processed food samples persisted during cooking. Furan was shown to form in foods on heating, although it did not accumulate to a significant degree on heating in an open vessel. There were no interactions between foods and cans, can coatings or gaskets that had a significant influence on furan formation. Furan accumulated particularly in heat-processed canned and jarred foods because they are sealed containers that receive a considerable thermal load. Heating epoxidized oils used in sealing gaskets formed furan. At the levels used in gaskets, however, epoxidized oils should not affect the formation of furan in foods.     

Effect of consumer cooking on furan in convenience foods

The effect of domestic preparation regimes on the level of the heat-formed toxicant furan was studied to provide useful information for exposure assessment and advice for manufacturers and consumers. Foods were cooked in a saucepan on a gas hob or microwaved and furan was determined by headspace sampling with gas chromatography-mass spectrometry. In general, furan levels did not decrease as much when foods were cooked in a microwave oven when compared with the same foods cooked in a saucepan. Furan levels decreased in most canned and jarred foods after heating in a saucepan. Low levels of furan in soups in cartons were not changed by any procedure. Furan decreased slightly in foods on standing before consumption, but did so more rapidly on stirring. The levels also decreased slightly when foods were left to stand on plates; this observation is attributed to the volatility of furan.     

Effect of consumer cooking on furan in convenience foods

The effect of domestic preparation regimes on the level of the heat-formed toxicant furan was studied to provide useful information for exposure assessment and advice for manufacturers and consumers. Foods were cooked in a saucepan on a gas hob or microwaved and furan was determined by headspace sampling with gas chromatography-mass spectrometry. In general, furan levels did not decrease as much when foods were cooked in a microwave oven when compared with the same foods cooked in a saucepan. Furan levels decreased in most canned and jarred foods after heating in a saucepan. Low levels of furan in soups in cartons were not changed by any procedure. Furan decreased slightly in foods on standing before consumption, but did so more rapidly on stirring. The levels also decreased slightly when foods were left to stand on plates; this observation is attributed to the volatility of furan.     

Vitamin Retention, Color and Texture in Thermally Processed Green Beans and Royal Ann Cherries Packed in Pouches and Cans

Thiamin (B-1) ascorbic acid (AA) and vitamin B-6 (B-6) were determined in pouched and canned green beans immediately after processing and after storage at 24–26°C or 38°C. AA and B-6 were also determined in pouched and canned cherries before and after storage at 24–26°C. There was significantly more B-1 and AA in drained pouched green beans, and more AA in drained pouched cherries than in canned ones. B-6 values in the solids of the pouched and canned products were not significantly different. These three vitamins were significantly reduced in drained pouched and canned green beans after storage at 38°C. B-6 was significantly reduced in the stored cherries. Compared to canned, the pouched products were brighter and firmer in texture.     

Headspace Liquid-Phase Microextraction Followed by Gas Chromatography–Mass Spectrometry for Determination of Furanic Compounds in Baby Foods and Method Optimization Using Response Surface Methodology

In the present study, a sensitive, rapid, and simple method for determination of furanic compounds in baby foods has been developed. Headspace liquid-phase microextraction (HS-LPME) coupled with gas chromatography–mass spectrometry was used to extract and measure furan, 2-methylfuran, and 2,5-dimethylfuran in baby foods. Effective parameters such as salt amount (NaCl), stirring rate, temperature, and time of extraction were optimized using response surface methodology based on a central composite design to obtain the best conditions for extracting furanic compounds. The optimum parameter values were 1 g NaCl, 700 rpm stirring rate, 40 °C extraction temperature, and 15 min extraction time. The calibration curves were linear over the range of 0.2–200 ng?mL^?1 (R ² ?>?0.99) for all compounds, and the repeatability of the method, described as relative standard deviation, ranged between 3.84 and 7.06 % (n?=?6). The recovery of spiked baby food sample after extraction ranged between 89.33 and 103.64 %, and the best enrichment factor was achieved about 972-fold for furan. The limits of detection and quantitation ranged between 0.021 and 0.038 ng?g^?1 and 0.069 and 0.126 ng?g^?1, respectively. The merit figures of the HS-LPME/GC-MS method showed that it can be considered as a new, fast, and effective alternative method for investigating furanic compounds in baby foods.     

Development of an analytical method and survey of foods for furan, 2-methylfuran and 3-methylfuran with estimated exposure

Furan has been found to form in foods during thermal processing. These findings, a classification of furan as a possibly carcinogenic to humans, and a limited amount of data on the concentration of furan in products on the Canadian market prompted the authors to conduct a survey of canned and jarred food products. Methyl analogues of furan, 2-methylfuran and 3-methylfuran, were analysed concurrently with furan via a newly developed isotope dilution method, as these analogues were detected in foods in the authors’ earlier work and are likely to undergo a similar metabolic fate as furan itself. The paper reports data on 176 samples, including 17 samples of baby food. The vast majority of samples were packaged in cans or jars. Furan was detected above 1 ng g^?1 in all non-baby food samples with a median of 28 ng g^?1 and concentrations ranging from 1.1 to 1230 ng g^?1. Also, 96% of these samples were found to contain 2-methylfuran above 1 ng g^?1 with a median of 12.8 ng g^?1 and a maximum concentration of 152 ng g^?1, while 81% of samples were found to contain 3-methylfuran above 1 ng g^?1 with a median of 6 ng g^?1 and a maximum concentration of 151 ng g^?1. Similarly, furan was detected above 1 ng g^?1 in all baby food samples with a median of 66.2 ng g^?1 and concentrations ranging from 8.5 to 331 ng g^?1. Also, 100% of these samples were found to contain 2-methylfuran above 1 ng g^?1 with a median of 8.7 ng g^?1 and a maximum concentration of 50.2 ng g^?1, while 65% of samples were found to contain 3-methylfuran above 1 ng g^?1 with a median of 1.6 ng g^?1 and a maximum concentration of 22.9 ng g^?1. Additionally, three coffee samples were analysed ‘as is’, without brewing, and were found to have high levels of furans, especially 2-methylfuran, at a maximum of 8680 ng g^?1. Using this data set, dietary exposures to furan and total furans were calculated. Average furan and total furan intakes by adults (≥20 years) were estimated at approximately 0.37 and 0.71 µg kg^?1 of body weight day^?1 respectively.     

Determination of furan levels in commercial samples of baby food from Brazil and preliminary risk assessment

Commercial baby food samples available on the Brazilian market (n = 31) were analysed for furan content using a gas chromatography-mass spectrometry method preceded by solid-phase microextraction. A limit of detection of 0.7 µg kg^?1, a limit of quantitation of 2.4 µg kg^?1, mean recoveries varying from 80% to 107%, and coefficients of variation ranging from 5.6% to 9.4% for repeatability and from 7.4% to 12.4% for within-laboratory reproducibility were obtained during an in-house validation. The levels of furan found in the samples were from not detected to 95.5 µg kg^?1. Samples containing vegetables and meat showed higher furan levels as compared with those containing only fruits. An exposure assessment showed furan intakes up to 2.4 µg kg^?1 body weight day^?1 (99th percentile) for babies fed exclusively with commercial baby foods. Margins of exposure obtained from intakes estimated in this work indicated a potential public health concern.     

Determination of furan in jarred baby food purchased from the Spanish market by headspace gas chromatography-mass spectrometry (HS-GC-MS)

The aim of this paper is to offer a method based on headspace gas chromatography-mass (HS-GC-MS) spectrometry technique in-house validated and use to estimate furan concentrations in jarred baby-food samples purchased from the Spanish market. The validation was performed according to ISO 17025 and European Food Safety Authority (EFSA) requirements and the results obtained (limit of detection (LOD) = 0.05 µg kg^?1; limit of quantification (LOQ) = 4 µg kg^?1, lowest validated level; relative standard deviation (RSD) = 3.1–10.5%; recoveries = 85.4–101.5%) confirm that this method is fit for the routine analysis of furan in jarred baby food control. Furan was analysed in 39 different baby-food samples and the mean levels varied between 64.6 µg kg^?1 (rice and chicken samples) and less than or equal to the LOQ (fruit-based samples). The mean concentrations found for the different matrices were 5.0, 37.8, 25.2, 33.8 and 30.5 µg kg^?1 for fruit, vegetables, meat/vegetables, fish/vegetables and dairy-containing baby foods, respectively. According to the statistical analyses, fruit-based baby-food samples had significantly lower concentrations of furan. Mean values for the other matrices were at least five times higher, and this is in accordance with the levels reported in other studies.     

Influences of Operating Parameters on the Formation of Furan During Heating Based on Models of Polyunsaturated Fatty Acids

Furan, a possible carcinogen, is commonly produced by thermal processing in a number of heated foods. The existence of furan levels in foods has attracted considerable attention worldwide. Recent research of furan in food has focused on the possible influences of operating parameters on the furan formation during heat processing. The aim of our study was to investigate the impacts of multiple factors (pH, temperature, heating time, ferric, and glutamic acid) on furan formation using linolenic and linoleic acids‐based model systems in which furan was analyzed by headspace gas chromatography–mass spectrometry (HS‐GC–MS). The results revealed that the content of furan increased rapidly when the heating temperature was elevated, with the highest levels of furan in neutral buffer solutions, the furan levels were also found to be related to heating time in all model systems. Ferric promoted furan formation from polyunsaturated fatty acids, conversely glutamic acid with an optimum concentration suppressed the furan formation. The minimal level of furan in foods during thermal treatment could be achieved via adding furan formation suppressors, and/or avoidance of furan forming promoter.     

EFFECT OF pH AND SOLUBLE SOLIDS ON THE SERUM VISCOSITY AND SERUM COLOR OF TOMATO JUICE AT ELEVATED TEMPERATURES1

Effects of heating time and temperature, pH, and soluble solid levels on serum viscosity and serum color of tomato juice were studied. The samples were canned in 18 mL TDT cans and exposed to processing temperatures of 88C, 102C, and 112C for 30, 60, and 120 min. Depending upon the time and temperature of heating, and initial viscosity of the serum, the losses in viscosity ranged from 3.0–55.6% being higher in serum with higher initial viscosity. Percent losses in serum viscosity during heating of juice increased (6–60%) with increase in pH (3.8–4.9) and soluble solids (6°–24°) in the juice. An increase in pH and soluble solids also enhanced heat induced browning in the serum with values varying from 0.1–2.69.     

Microwave Finish Drying of Diced Apples in a Spouted Bed

The combination of a spouted bed with microwave heating to improve heating uniformity was evaluated. Experiments were performed on a laboratory system in which evaporated diced apples of about 24% moisture were dried to about 5% at 70°C air temperature using four levels of microwave power density (0 to 6.1 W/g). With the combination method, temperature uniformity in diced apples was greatly improved as compared to that with a stationary bed during microwave drying. Products had less discoloration and higher rehydration rates as compared to conventional hot air drying or spouted bed (SB) drying. Drying time could be reduced by >80% compared with SB drying without microwave heating.     

Migration of bisphenol A from plastic baby bottles,baby bottle liners and reusable polycarbonate drinking bottles

Human exposure to bisphenol A (BPA) has recently received special attention. It has been shown that exposure to BPA may occur through the consumption of beverages or foods that have been in contact with polycarbonate (PC) plastic containers or epoxy resins in food packaging. A BPA migration study was conducted using a variety of plastic containers, including polycarbonate baby bottles, non-PC baby bottles, baby bottle liners, and reusable PC drinking bottles. Water was used to simulate migration into aqueous and acidic foods; 10% ethanol solution to simulate migration to low- and high-alcoholic foods; and 50% ethanol solution to simulate migration to fatty foods. By combining solid-phase extraction, BPA derivatization and analysis by GC-EI/MS/MS, a very low detection limit at the ng l^?1 level was obtained. Migration of BPA at 40°C ranged from 0.11 µg l^?1 in water incubated for 8 h to 2.39 µg l^?1 in 50% ethanol incubated for 240 h. Residual BPA leaching from PC bottles increased with temperature and incubation time. In comparison with the migration observed from PC bottles, non-PC baby bottles and baby bottle liners showed only trace levels of BPA. Tests for leachable lead and cadmium were also conducted on glass baby bottles since these represent a potential alternative to plastic bottles. No detectable lead or cadmium was found to leach from the glass. This study indicated that non-PC plastic baby bottles, baby bottle liners and glass baby bottles might be good alternatives for polycarbonate bottles.