Scientific Opinion on the re‐evaluation of caramel colours (E 150 a,b,c,d) as food additives

Research progress on generation, detection and inhibition of multiple hazards - acrylamide, 5-hydroxymethylfurfural, advanced glycation end products, methylimidazole - in baked goods

While baking produces attractive flavors for foods, it also generates various endogenous by-products, including acrylamide (AA), 5-hydroxymethylfurfural (5-HMF), advanced glycation end products (AGEs) and methylimidazole (MI). This review briefly presents the recent studies on the above hazards, and research progress on the formation and control of the above substances in detail. There have been more detailed studies on a single category of hazards. However, few studies and reports have considered the integrated prevention and control of multiple hazards, which is related to the difficulty of analyzing the reaction mechanisms of multiple hazards at multiple scales and under multiple phases in complex food matrices. In this regard, the sample pretreatment methods are a crucial step in achieving simultaneous detection. The coordinated implementation of various methods, including reducing precursor levels, modifying baking conditions and equipment, and incorporating exogenous additives, is necessary to achieve a synchronized reduction in multiple hazardous substances.

Dyes Used in Processed Meat Products in the Polish Market, and Their Possible Risks and Benefits for Consumer Health

Manufacturers are obliged to label processed meat products with information concerning the additives used and nutritional values. The aim of the study was to identify the dyes most frequently used in processed meat, evaluate their influence on specific food qualities, assess whether their use was correct and review their effect on health. The analysis was based on information on the labels and images of processed meat, and used a generalised linear model with a binary dependent variable. The risks and benefits for human health were defined based on the available literature. Twelve dyes were found to be used in the manufacture of processed meat. Carmine was found in 183 of 273 (67.03%) evaluated assortments containing dyes. The occurrence of water, flavourings and high fat and carbohydrate contents increased the chances that a dye would be present in a particular product. Unauthorised use of food additives was found in 20 products, with smoked meat products demonstrating the highest number of non-compliances. In general, the dyes used with food are considered safe; however, reservations are associated with the use of E150C and E150D caramels due to their potential carcinogenic effect, and carmine and annatto due to their allergic effects.

Review on Furan as a Food Processing Contaminant: Identifying Research Progress and Technical Challenges for Future Research

A wide range of food processing contaminants (FPCs) are usually formed while thermal processing of food products. Furan is a highly volatile compound among FPCs and could be formed in a variety of thermally processed foods. Therefore, identification of possible reasons of furan occurrence in different thermally processed foods, identification of the most consequential sources of furan exposure, factors impacting its formation, and its detection by specific analytical approaches are necessary to indicate gaps and challenges for future research findings. Furthermore, controlling furan formation in processed foods on a factory scale is also challenging, and research advancements are still ongoing in this context. Meanwhile, understanding adverse effects of furan on human health on a molecular level is necessary to gain insights into human risk assessment.

Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk

Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.

Treatment technologies for bakers' yeast production wastewater

Researchers in recent years have utilized a broad spectrum of treatment technologies in treating bakers' yeast production wastewater. This paper aims to review the treatment technologies for the wastewater, compare the process technologies, discuss recent innovations, and propose future perspectives in the research area. The review observed that nanofiltration was the most effective membrane process for the treatment of the effluent (at >95% pollutant rejection). Other separation processes like adsorption and distillation had technical challenges of desorption, a poor fit for high pollutant load and cost limitations. Chemical treatment processes have varying levels of success but they are expensive and produce toxic sludge. Sludge production would be a hurdle when product recovery and reuse are targeted. It is difficult to make an outright choice of the best process for treating the effluent because each has its merits and demerits and an appropriate choice can be made when all factors are duly considered. The process intensification of the industrial-scale production of the bakers' yeast process will be a very direct approach, where the process optimisation, zero effluent discharge, and enhanced recovery of value-added product from the waste streams are important approaches that need to be taken into account.

Food Colour Additives: A Synoptical Overview on Their Chemical Properties, Applications in Food Products, and Health Side Effects

Colour is one of the most relevant organoleptic attributes that directly affects consumers' acceptance and food selection. However, as food colouring pigments are generally unstable and become modified during processing, in order to maintain or restore product colour uniformity, colourants are added to food products around the world. In this context, although they are still widely used, synthetic food colorants, due to their potential hazards, are being replaced by those obtained from natural origins. Indeed, numerous side effects and toxicities, at both the medium and long-terms-namely allergic reactions, and behavioral and neurocognitive effects-have been related to the use of synthetic colourants, whereas their naturally-derived counterparts seem to provide a somewhat high-quality and effective contribution as a health promoter. In order to further understand the implications of the use of synthetic and naturally derived food colourants, this review aims to provide a synoptical approach to the chemical characteristics, properties, uses and side effects on health of those which are currently allowed and applied during food processing.

Caramel colors in terms of scientific research, with particular consideration of their toxicity

Caramel colors, the most common food additives in the world, are divided into four classes (IIV), marked with the symbols E150 a-d, respectively. Individual classes of caramel colors differ from each other in physico-chemical properties and the method of preparation, which affects the formation of various compounds that are important for the assessment of food safety A number of studies on all caramel classes of have been performed, including toxicokinetic, genotoxic, carcinogenic and reproductive and developmental toxicity studies, which have not shown harmful effects of these additives at doses not exceeding ADI. However, there is an increasing number of scientific reports of the possible toxic effects present in caramels of low-molecular compounds. Currently, three compounds are considered to be toxicologically important and resulting from the possible concentration in the final product: 5-HMF (present in all classes), 4(5)-MeI (present in caramel classes III and IV) or THI (present in caramel class III). 4(5)-MeI has a neurotoxic effect and was considered in 2011 as a possible human carcinogen (class 2B, according to IARC). In the case of THI, studies have confirmed its lymphopenic activity, probably secondary to its immunosuppressive effect. Consequently, in the 1980s, JECFA set acceptable levels 4(5)-MeI and THI, for the caramel classes in which these compounds may be present. The toxicity of 5-HMF has not been confirmed unequivocally, but studies have shown that this compound is not neutral to living organisms. Currently, most international organizations and scientific institutes recognize these additives as safe for consumers, but at the same time scientists emphasize the need for further research.

A standardized polyphenol mixture extracted from poplar-type propolis for remission of symptoms of uncomplicated upper respiratory tract infection (URTI): A monocentric, randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

The most common symptoms of mild upper respiratory tract infections (URTIs) are sore throat, muffled dysphonia, and swelling and redness of the throat, which result from the inflammation process following acute bacterial or viral infection.

HYPOTHESIS/PURPOSE

As propolis is a natural resinous substance traditionally used to maintain oral cavity and upper respiratory tract health due to its antimicrobial and anti-inflammatory properties, the aim of this study is to evaluate the efficacy of an oral spray based on poplar-type propolis extract with a known and standardized polyphenol content, on the remission of the symptoms associated with mild uncomplicated URTIs.

STUDY DESIGN

A monocentric, randomized, double-blind, placebo-controlled clinical trial was performed.

METHODS

This study was conducted in 122 healthy adults who had perceived mild upper respiratory tract infections. Participants, randomly assigned to receive either propolis oral spray (N = 58) or placebo (N = 64), underwent four visits (baseline = t0, after 3 days = t1 and after 5 days = t2 and after a follow-up of 15 days = t3) in an outpatient setting. Propolis oral spray total polyphenol content was 15 mg/ml. The dosage was 2-4 sprays three times/day (corresponding to 12-24 mg of polyphenols/day), for five days. The duration of the study was 8 weeks.

RESULTS

After 3 days of treatment, 83% of subjects treated with propolis oral spray had remission of symptoms, while 72% of subjects in the placebo group had at least one remaining symptom. After five days, all subjects had recovered from all symptoms. This means that resolution from mild uncomplicated URTIs took place two days earlier, instead of taking place in five days as recorded in the control group. There was no relationship between the ingestion of propolis oral spray or placebo and adverse reactions.

CONCLUSION

Propolis oral spray can be used to improve both bacterial and viral uncomplicated URTI symptoms in a smaller number of days without the use of pharmacological treatment, leading to a prompt symptom resolution.

Influence of caramel and molasses addition on acrylamide and 5-hydroxylmethylfurfural formation and sensory characteristics of non-centrifugal cane sugar during manufacturing

BACKGROUND

The aims of this study are to (i) evaluate the effects of color enhancers, caramel (C) and molasses (M), on acrylamide and 5-hydroxylmethylfurfural (HMF) formation in non-centrifugal cane sugar (NCS) and to (ii) perform nine-point hedonic scale and evaluation of sensory attributes, encompassing the appearance, flavor, texture and aftertaste, by 71 consumers on NCS, NCS_C, and NCS products made with a blend of molasses and sugar (NCS_MS) and steam processing (NCS_S).

RESULTS

With the addition of molasses and caramel at the maximum allowable level of 5 g kg^-1 in sugarcane juice, significantly greater acrylamide or HMF did not accumulate in NCS_C and NCS_M during the thermal manufacturing process, while color values of NCS_C significantly changed (P < 0.05). The increases in acrylamide and HMF contents were influenced by pH because they were produced by the Maillard reaction. Hedonic responses showed that NCS_MS was rated with the highest score for overall acceptance, whereas NCS_S, with the lowest content of acrylamide, exhibited the lowest score for every attribute. In addition, the appearance acceptance score of NCS_C was significantly higher than that of NCS (P < 0.05). Significant differences were also found between NCS and NCS_C in the frequency of 9 of 16 items with which consumers selected to characterize the appearance in a check-all-that-apply questionnaire (P < 0.05).

CONCLUSIONS

The association between hedonic evaluations and sensory profiles in visual attributes of NCS_C indicated that caramel could be a promising addition in Maillard reaction-mitigated NCS products to improve consumer preferences through color strengthening without safety concerns. © 2020 Society of Chemical Industry.

Acrylamide and Thermal-Processing Indexes in Market-Purchased Food

Determining acrylamide (AA) content in foods using chromatographic methods is expensive and time-consuming. Therefore, there is a need to develop a simple, economical method for monitoring the content of acrylamide in foods. This study analysed whether there is a relationship between acrylamide levels with some heat-induced parameters, such as 5-hydroxymethylfurfural (HMF) and browning, in order to assess their usefulness in predicting the potential acrylamide levels in market-purchased food. Sixty plant-based food products were tested. The correlation coefficients for AA levels with L*, a* and b* values and HMF content were significant (p < 0.05) for French fries and potato chips. There was no statistically significant correlation between thermal-processing indexes (HMF and colour parameters) and acrylamide levels in commercial bread, breakfast cereals and biscuits. The results indicate that these classical thermal-processing indexes are not directly related to the acrylamide content in commercial cereal-based food and they cannot be indicators of AA level. Thus, the correlation between HMF and colour parameters with acrylamide content depends on the type of food and it is difficult to estimate the amount of AA based on these classical thermal-processing indexes of market-purchased food.

Sous-Vide Nonenzymatic Browning of Glucosamine at Different Temperatures

Sous-vide is an increasingly popular method of cooking under controlled conditions of temperature and time inside vacuumed pouches to preserve the nutritional and sensory qualities of food. Sous-vide nonenzymatic browning of glucosamine (GlcN) was investigated at 50, 60, and 70 °C for 12 h. Changes investigated were pH, color, level of browning, and the concentrations of the key Maillard and caramelization reaction products, including α-dicarbonyls and pyrazines. The concentrations of undesired 4-methylimidazole (4-MEI), 2-acetyl-4(5)-tetrahydroxybutyl imidazole (THI), and 5-hydroxymethylfurfural (5-HMF) were also determined. Six types of caramels were produced of unique composition with no detectable levels of 4-MEI. GlcN caramels produced under vacuum were more acidic and lighter in color, containing significantly less flavorful diacetyl, but more fructosazine (FR) as compared to nonvacuum caramels. THI concentration was well below the toxicity levels for all studied caramels. Principal component analyses showed that the incubation temperature played a key role in determining the composition of caramels.

Genotoxicity assessment of 4-methylimidazole: regulatory perspectives

4-Methylimidazole (4-MI) is formed as a result of the Maillard reaction process, and therefore is found in many foods and beverages. It is also found in soft drinks (i.e., cola) as a by-product in the production of some caramel colors. NTP bioassays revealed clear evidence of lung carcinogenicity of 4-MI in male and female mice, but not in rats and then IARC classified 4-MI as group 2B carcinogen. Genotoxicity studies with 4-MI were negative in the Ames tests and in the erythrocyte micronucleus tests with mice or rats. US California EPA (CEPA) evaluated the testing has not been adequately comprehensive to rule out a genotoxic mode of action; as target tissue of the carcinogenicity of 4-MI was lung, the lung should be used as a source tissue for in vitro metabolic activation system. Thus, CEPA defined the No Significant Risk Level (NSRL) for 10-5 lifetime risk level of cancer by 4-MI as 29 μg/day based on the non-threshold approach. As higher levels of 4-MI than the NSRL were identified in some kinds of cola, health concerns of 4-MI were drawn the attention. On the other hand, other regulatory bodies (e.g., European Food Safety Authority, EFSA) showed no concerns of 4-MI from the use of caramel colors in food. EFSA evaluated 4-MI is not genotoxic, so, non-observed adverse effect level of 4-MI was considered to be 80 mg/kg/day. In this paper, genotoxic assessments of 4-MI in different regulatory bodies are presented and the risk evaluation of 4-MI is discussed based on new genotoxicity data.

Carcinogenic compounds in alcoholic beverages: an update

The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC. For most of the compounds of alcoholic beverages, quantitative risk assessment provided evidence for only a very low risk (such as margins of exposure above 10,000). The highest risk was found for ethanol, which may reach exposures in ranges known to increase the cancer risk even at moderate drinking (margin of exposure around 1). Other constituents that could pose a risk to the drinker were inorganic lead, arsenic, acetaldehyde, cadmium and ethyl carbamate, for most of which mitigation by good manufacturing practices is possible. Nevertheless, due to the major effect of ethanol, the cancer burden due to alcohol consumption can only be reduced by reducing alcohol consumption in general or by lowering the alcoholic strength of beverages.

Reduction of carcinogenic 4(5)-methylimidazole in a caramel model system: influence of food additives

The effect of various food additives on the formation of carcinogenic 4(5)-methylimidazole (4-MI) in a caramel model system was investigated. The relationship between the levels of 4-MI and various pyrazines was studied. When glucose and ammonium hydroxide were heated, the amount of 4-MI was 556 ± 1.3 μg/mL, which increased to 583 ± 2.6 μg/mL by the addition of 0.1 M of sodium sulfite. When various food additives, such as 0.1 M of iron sulfate, magnesium sulfate, zinc sulfate, tryptophan, and cysteine were added, the amount of 4-MI was reduced to 110 ± 0.7, 483 ± 2.0, 460 ± 2.0, 409 ± 4.4, and 397 ± 1.7 μg/mL, respectively. The greatest reduction, 80%, occurred with the addition of iron sulfate. Among the 12 pyrazines, 2-ethyl-6-methylpyrazine with 4-MI showed the highest correlation (r = -0.8239).

Inhibition of human pyridoxal kinase by 2-acetyl-4-((1R,2S,3R)-1,2,3,4-tetrahydroxybutyl)imidazole (THI)

2-Acetyl-4-((1R,2S,3R)-1,2,3,4-tetrahydroxybutyl)imidazole (THI) is observed as a minor contaminant in caramel food colourings (E 150c). Feeding experiments with rodents have revealed a significant lymphopenic effect that has been linked to the presence of THI in these food colourings. Pyridoxal kinase inhibition by THI has been suggested, but not demonstrated, as a mode of action as it leads to lowered levels of pyridoxal-5'-phosphate, which are known to cause lymphopenia. Recently, THI was also shown to inhibit sphingosine-1-phosphate lyase causing comparable immunosuppressive effects and derivatives of THI are being developed for the treatment of rheumatoid arthritis in humans. Interestingly, sphingosine-1-phosphate lyase activity depends on pyridoxal-5'-phosphate, which in turn is provided by pyridoxal kinase. This report shows that THI does inhibit pyridoxal kinase with competitive and mixed-type non-competitive behaviour towards its two substrates, pyridoxal and ATP, respectively. The corresponding inhibition constants are in the low millimolar range.

Determination of 2-methylimidazole, 4-methylimidazole and 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl)imidazole in caramel colours and cola using LC/MS/MS

Substituted imidazoles recently came under scrutiny as they may be indirectly introduced into cola beverages via the use of class IV (E150d) caramel colours and may pose health hazards. A LC/MS/MS method was developed for determining 2- and 4-methylimidazole (2-MI, 4-MI) and 2-acetyl-4-(1,2,3,4)-tetrahydroxybutylimidazole (THI) in beverages and caramel colours. The method is very rapid and easy to conduct as it requires only dilution in eluent for sample preparation. For 4-MI, the recovery was between 94 and 102% for spiked cola samples. The limit of detection was 2μg/L in the measuring solution (corresponding to 40μg/L for cola samples diluted 1:20 during sample preparation). 97 cola samples and 13 caramel colours from Germany and France were analysed. From the 3 analytes, only 4-MI was found in the samples with very varying concentrations (non quantifiable traces to 0.6mg/L in colas and 175-658mg/kg in E150d). The exposure for cola drinkers in worst case scenarios is estimated to be 2-5μg/kg bodyweight/day, which is judged as being only a low risk for public health.

Comparative risk assessment of carcinogens in alcoholic beverages using the margin of exposure approach

Alcoholic beverages have been classified as carcinogenic to humans. As alcoholic beverages are multicomponent mixtures containing several carcinogenic compounds, a quantitative approach is necessary to compare the risks. Fifteen known and suspected human carcinogens (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, lead, 4-methylimidazole, N-nitrosodimethylamine, ochratoxin A and safrole) occurring in alcoholic beverages were identified based on monograph reviews by the International Agency for Research on Cancer. The margin of exposure (MOE) approach was used for comparative risk assessment. MOE compares a toxicological threshold with the exposure. MOEs above 10,000 are judged as low priority for risk management action. MOEs were calculated for different drinking scenarios (low risk and heavy drinking) and different levels of contamination for four beverage groups (beer, wine, spirits and unrecorded alcohol). The lowest MOEs were found for ethanol (3.1 for low risk and 0.8 for heavy drinking). Inorganic lead and arsenic have average MOEs between 10 and 300, followed by acetaldehyde, cadmium and ethyl carbamate between 1,000 and 10,000. All other compounds had average MOEs above 10,000 independent of beverage type. Ethanol was identified as the most important carcinogen in alcoholic beverages, with clear dose response. Some other compounds (lead, arsenic, ethyl carbamate, acetaldehyde) may pose risks below thresholds normally tolerated for food contaminants, but from a cost-effectiveness point of view, the focus should be on reducing alcohol consumption in general rather than on mitigative measures for some contaminants that contribute only to a limited extent (if at all) to the total health risk.