Acrylamide determination during an industrial roasting process of coffee and the influence of asparagine and low molecular weight sugars

Tea's Characteristic Components Eliminate Acrylamide in the Maillard Model System

This study investigated the effects of various characteristic components of tea-theaflavins, catechins, thearubigins, theasinensins, theanine, catechin (C), catechin gallate (CG), epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), and gallocatechin gallate (GCG)-on acrylamide formation. The results revealed that most of tea's characteristic components could significantly eliminate acrylamide, ranked from highest to lowest as follows: GC (55.73%) > EC (46.31%) > theaflavins (44.91%) > CG (40.73%) > thearubigins (37.36%) > ECG (37.03%) > EGCG (27.37%) > theabrownine (22.54%) > GCG (16.21%) > catechins (10.14%) > C (7.48%). Synergistic elimination effects were observed with thearubigins + EC + GC + CG, thearubigins + EC + CG, thearubigins + EC + GC, theaflavins + GC + CG, and thearubigins + theaflavins, with the reduction rates being 73.99%, 72.67%, 67.62%, 71.03%, and 65.74%, respectively. Tea's components reduced the numbers of persistent free radicals to prevent acrylamide formation in the model system. The results provide a theoretical basis for the development of low-acrylamide foods and the application of tea resources in the food industry.

Insights into acrylamide and furanic compounds in coffee with a focus on roasting methods and additives

Roasting is necessary for bringing out the aroma and flavor of coffee beans, making coffee one of the most consumed beverages. However, this process also generates a series of toxic compounds, including acrylamide and furanic compounds (5-hydroxymethylfurfural, furan, 2-methylfuran, 3-methylfuran, 2,3-dimethylfuran, and 2,5-dimethylfuran). Furthermore, not much is known about the formation of these compounds in emerging coffee formulations containing alcohol and sugars. Therefore, this study investigated the effect of roasting time and degree on levels of acrylamide and furanic compounds in arabica coffee using fast and slow roasting methods. The fast and slow roasting methods took 5.62 min and 9.65 min, respectively, and reached a maximum of 210 °C to achieve a light roast. For the very dark roast, the coffee beans were roasted for 10.5 min and the maximum temperature reached 245 °C. Our findings showed that the levels of acrylamide (375 ± 2.52 μg kg-1) and 5-HMF (194 ± 11.7 mg kg-1) in the slow-roasted coffee were 35.0 % and 17.4 % lower than in fast-roasted coffee. Furthermore, light roast coffee had significantly lower concentrations of acrylamide and 5-HMF than very dark roast, with values of 93.7 ± 7.51 μg kg-1 and 21.3 ± 10.3 mg kg-1, respectively. However, the levels of furan and alkylfurans increased with increasing roasting time and degree. In this study, we also examined the concentrations of these pollutants in new coffee formulations consisting of alcohol-, sugar-, and honey-infused coffee beans. Formulations with honey and sugar resulted in higher concentrations of 5-HMF, but no clear trend was observed for acrylamide. On the other hand, formulations with honey had higher concentrations of furan and alkylfurans. These results indicate that optimizing roasting time and temperature might not achieve the simultaneous reduction of all the pollutants. Additionally, sugar- and honey-infused coffee beans are bound to have higher furanic compounds, posing a higher health risk.

Acrylamide formation in air-fryer roasted legumes as affected by legume species and roasting degree: the correlation of acrylamide with asparagine and free sugars

Acrylamide is a well-recognized hazardous compound with known carcinogenic, genotoxic, neurotoxic, and reproductive toxic effects. This research aimed to investigate how different legume species and roasting durations influence acrylamide formation during air-fryer roasting. The study also examined the relationship between acrylamide formation and the levels of free asparagine and free sugars in different bean species. Asparagine content varies substantially across different bean species. Sucrose was the predominant sugar across all bean species, with smaller amounts of galactose and glucose. Air-fryer-roasted Wandu kong (garden pea) showed the highest acrylamide formation, followed by Ultari kong (kidney bean) and Heoktae (black soybean), in that order. Beans roasted for longer periods in an air fryer contained significantly higher levels of acrylamide. This study revealed a strong positive correlation between acrylamide formation and the level of free asparagine in the beans, highlighting the risks associated with certain legume species and air-fryer roasting durations.

Enhancing analysis of neo-formed contaminants in two relevant food global commodities: Coffee and cocoa

Neo-formed contaminants (NFCs) are common in many foods, especially those subjected to high-temperature processing. Among these contaminants, products arising from the Maillard reaction, sugar reduction, thermal degradation of polyphenols and lipid oxidation, including acrylamide, furan, furfuryl alcohol, and hydroxymethylfurfural, are consistently linked to potential neoplastic effects. NFCs are found in globally traded commodities like coffee and cocoa, posing a significant risk due to their frequent consumption by consumers. A direct correlation exists between consumption frequency, exposure levels, and health risks. Hence, it's crucial to establish reliable methods to determine levels in both matrices, aiming to mitigate their formation and minimise risks to consumers. This review offers a comprehensive examination, discussion, and identification of emerging trends and opportunities to enhance existing methodologies for extracting and quantifying NFCs in coffee and cocoa. By presenting an in-depth analysis of performance parameters, we aim to guide the selection of optimal extraction techniques for quantifying individual NFCs. Based on the reviewed data, headspace extraction is recommended for furan, while solid and dispersive solid phase extractions are preferred for acrylamide when quantified using gas and liquid chromatography, respectively. However, it is worth noting that the reported linearity tests for certain methods did not confirm the absence of matrix effects unless developed through standard addition, leading to uncertainties in the reported values. There is a need for further research to verify method parameters, especially for determining NFCs like furfuryl alcohol. Additionally, optimising extraction and separation methods is essential to ensure complete compound depletion from samples. Ideally, developed methods should offer comprehensive NFC determination, reduce analysis time and solvent use, and adhere to validation parameters. This review discusses current methods for extracting and quantifying NFCs in coffee and cocoa, highlighting emerging trends and emphasising the need to improve existing techniques, especially for compounds like furfuryl alcohol.

Blood RNA-sequencing analysis in acrylamide-induced neurotoxicity and depressive symptoms in rats

Acrylamide (ACR) is a by-product of the Maillard reaction, which occurs when food reacts at high temperatures. Occupational exposure is a risk factor for chronic ACR toxicity. ACR may cause neurotoxicity and depressive symptoms with high concentration in the blood; however, the underlying mechanism remains unknown. We showed the rats developed neurotoxic symptoms after being fed with ACR for 28 days, such as reduced activity and hind limb muscle weakness. We investigated whether ACR exposure causes gene expression differences by blood RNA sequencing and analyzed the differential expression of depressive symptoms-associated genes. The result indicated that IFN-γ the key regulator of neurotoxicity and depressive symptoms was induced by ACR. ACR induced the ubiquitin-mediated proteolysis pathway and JAK/STAT pathways gene expression. ACR upregulated the expression of IFN-γ, inducing neuroinflammation and neurotoxicity. ACR also upregulated the expression of JAK2, STAT1, PI3K, AKT, IκBα, UBE2D4, NF-κB, TNF-α, and iNOS in rat brain tissues and Neuro-2a cells. Thus, IFN-γ induction by ACR may induce depressive symptoms, and the ubiquitin-mediated proteolysis pathway and JAK/STAT pathways may involve in ACR neurotoxicity and depressive symptoms.

Identifying high-risk factors and mitigation strategies for acrylamide formation in air-fried lotus root chips: Impact of cooking parameters, including temperature, time, presoaking, and seasoning

This study was conducted to identify high-risk factors and mitigation strategies for acrylamide formation in air-fried lotus root chips by studying the impact of various cooking parameters, including temperature, time, presoaking, and pre-seasoning treatments. The temperature and time had a surprisingly high impact on acrylamide formation. The chips prepared at high temperatures with longer cooking times contained an extremely high acrylamide content, reaching 12,786 ng/g (e.g., 170°C/19 min). A particularly concerning discovery was that the chips with extremely high acrylamide content (up to 17 times higher than the EU benchmark level for potato chips) did not appear overcooked or taste burnt. Higher cooking temperatures required shorter cooking times to properly cook lotus root chips for consumption. A high temperature with a short cooking time (170°C/13 min) greatly benefited acrylamide reduction compared to low temperature with a long cooking time (150°C/19 min). Presoaking in a 0.1% acetic acid solution and pre-seasoning with 1% salt reduced acrylamide levels by 61% and 47%, respectively. However, presoaking in water, vinegar solution, and citric acid solution did not significantly decrease the acrylamide content in the chips. Furthermore, some seasonings significantly increased acrylamide levels (up to 7.4 times higher). For the first time, these findings underscore the high risks associated with air-frying lotus root chips without considering these factors. This study also provides proper air-frying parameters and pretreatment strategies for minimizing acrylamide formation in air-fried lotus chips.

A label-free aptasensor for colorimetric detection of food toxin: Mediation of catalytically active gold nanozymes and smartphone imaging strategy

A portable colorimetric aptasensor was developed on the surface of a plastic sheet for on-site detection of acrylamide. The mechanism of aptasensor is based on the disruption of the aptamer complex with its complementary strand on the sensing zone, and subsequently, the catalytic activity of gold nanoparticles (AuNPs) for the reduction process of 4-nitrophenol (4-NP) in the presence of sodium borohydride (NaBH4). A yellow-to-colorless change of the sample solution revealed the target presence, easily discernible by the naked eye. The acrylamide quantification was accomplished using the smartphone imaging readout technique. The aptasensor detected the acrylamide concentration in the range of 0.01-500 nmol L-1 with a detection limit of 0.0024 nmol L-1. Coffee, potato chips, bread, and lake water samples were successfully analyzed by the aptasensor for their acrylamide content. The introduced aptasensor can pave a facile, cost-effective, portable, and user-friendly sensing tool for food safety control and environmental monitoring.

Toxicity, metabolism, and mitigation strategies of acrylamide: a comprehensive review

Acrylamide, a food-borne chemical toxicant, has raised global concern in recent decades. It mainly originated from reducing sugar and free amino acid interactions in the carbohydrate-rich foodstuffs heated at high temperatures. Due to the neurotoxicity and carcinogenicity of AA, the mechanism of formation, toxic effects on health, and mitigation strategies, including conventional approaches and innovative technologies, have been of great interest since its discovery in food. Potato products (especially French fries and crisps), coffee, and cereals(bread and biscuit) are renowned contributors to AA's daily intake. The best preventive methods discussed in the literature include time/temperature optimization, blanching, enzymatic treatment, yeast treatment, additives, pulsed electric fields, ultrasound, vacuum roasting, air frying, and irradiation, exhibiting a high efficacy in AA elimination in food products.

Effective mitigation in the amount of acrylamide through enzymatic approaches

Acrylamide (AA), as a food-borne toxicant, is created at some stages of thermal processing in the starchy food through Maillard reaction, fatty food via acrolein route, and proteinous food using free amino acids pathway. Maillard reaction obviously takes place in thermal-based products, being responsible for specific sensory attributes; AA formation, thereby, is unavoidable during the thermal processing. Additionally, AA can naturally occur in soil and water supply. In order to reduce the levels of acrylamide in cooked foods, mitigation techniques can be separated into three different types. Firstly, starting materials low in acrylamide precursors can be used to reduce the acrylamide in the final product. Secondly, process conditions may be modified in order to decrease the amount of acrylamide formation. Thirdly, post-process intervention could be used to reduce acrylamide. Conventional or emerging mitigation techniques might negatively influence the pleasant features of heated foods. The current study summarizes the effect of enzymatic reaction induced by asparaginase, glucose oxidase, acrylamidase, phytase, amylase, and protease to possibly inhibit AA formation or progressively hydrolyze formed AA. Not only enzyme-assisted AA reduction could dramatically maintain bio-active compounds, but also no damaging impact has been reported on the sensorial and rheological properties of the final heated products. The enzyme engineering can be applied to ameliorate enzyme functionality through altering the amino acid sequence like site-specific mutagenesis and directed evolution, chemical modifications by covalent conjugation of L-asparaginase onto soluble/insoluble biocompatible polymers and immobilization. Moreover, it would be possible to improve the enzyme's physical, chemical, and thermal stability, recyclability and prevent enzyme overuse by applying engineered ones. In spite of enzymes' cost-effective and eco-friendly, promoting their large-scale usages for AA reduction in food application and AA bioremediation in wastewater and soil resources.

Characterizing the formation of process contaminants during coffee roasting by multivariate statistical analysis

Coffee is a relevant source of dietary exposure for neoformed furan, alkyl furans and acrylamide. In this study, different statistical methods (hierarchical cluster analysis, correlation analysis, partial least squares regression analysis) were used for characterizing the formation of these process contaminants in green coffee beans roasted under the same standardized conditions. The results displayed a strong correlation between sucrose levels and furans in relation to the other sugars analyzed, while acrylamide formation was strongly related to the free asparagine. The data suggest that a sufficiently large amino acid pool in green coffee favors Maillard-induced acrylamide formation from asparagine, while reactions amongst the carbonyl-containing sugar fragmentation products leading to furan formation are suppressed. If the pool of free amino acids is small, it is depleted faster during roasting, thus favoring the formation of furans by caramelization, basically a sugar degradation process in which reactive carbonyl substances are generated and react together.

Effects of intramolecular proton acceptors located near sulfhydryl groups on sulfhydryl compounds for acrylamide elimination

To explore the effects of intramolecular neighboring groups on sulfhydryl group reactivity in acrylamide removal, the reactions of three sulfhydryl-containing flavoring substances with derived structures, 1-propanethiol, 3-mercaptopropionic acid, and cysteine, with acrylamide were investigated. The results showed that the activation energies of the reactions decreased with the introduction of amino and carboxyl groups. Additional comparison reactions showed that other proton acceptors also promote the reactions of sulfhydryl groups with acrylamide. However, the reactivity was not enhanced if the proton acceptor was located far from the sulfhydryl group. This suggested that sulfhydryl compounds with the molecular structure of proton acceptors on the carbons located β or/and γ to the sulfhydryl group were efficient in eliminating acrylamide, and the results are expected to serve as a guide in the search for effective acrylamide elimination agents.

Toxicity, formation, contamination, determination and mitigation of acrylamide in thermally processed plant-based foods and herbal medicines: A review

Thermal processing is one of the important techniques for most of the plant-based food and herb medicines before consumption and application in order to meet the specific requirement. The plant and herbs are rich in amino acids and reducing sugars, and thermal processing may lead to Maillard reaction, resulting as a high risk of acrylamide pollution. Acrylamide, an organic pollutant that can be absorbed by the body through the respiratory tract, digestive tract, skin and mucous membranes, has potential carcinogenicity, neurological, genetic, reproductive and developmental toxicity. Therefore, it is significant to conduct pollution determination and risk assessment for quality assurance and security of medication. This review demonstrates state-of-the-art research of acrylamide focusing on the toxicity, formation, contamination, determination, and mitigation in taking food and herb medicine, to provide reference for scientific processing and ensure the security of consumers.

Thermal Contaminants in Coffee Induced by Roasting: A Review

Roasting is responsible for imparting the main characteristics to coffee, but the high temperatures used in the process can lead to the formation of several potentially toxic substances. Among them, polycyclic aromatic hydrocarbons, acrylamide, furan and its derivative compounds, α-dicarbonyls and advanced glycation end products, 4-methylimidazole, and chloropropanols stand out. The objective of this review is to present a current and comprehensive overview of the chemical contaminants formed during coffee roasting, including a discussion of mitigation strategies reported in the literature to decrease the concentration of these toxicants. Although the formation of the contaminants occurs during the roasting step, knowledge of the coffee production chain as a whole is important to understand the main variables that will impact their concentrations in the different coffee products. The precursors and routes of formation are generally different for each contaminant, and the formed concentrations can be quite high for some substances. In addition, the study highlights several mitigation strategies related to decreasing the concentration of precursors, modifying process conditions and eliminating/degrading the formed contaminant. Many of these strategies show promising results, but there are still challenges to be overcome, since little information is available about advantages and disadvantages in relation to aspects such as costs, potential for application on an industrial scale and impacts on sensory properties.

Production and Inhibition of Acrylamide during Coffee Processing: A Literature Review

Coffee is the third-largest beverage with wide-scale production. It is consumed by a large number of people worldwide. However, acrylamide (AA) is produced during coffee processing, which seriously affects its quality and safety. Coffee beans are rich in asparagine and carbohydrates, which are precursors of the Maillard reaction and AA. AA produced during coffee processing increases the risk of damage to the nervous system, immune system, and genetic makeup of humans. Here, we briefly introduce the formation and harmful effects of AA during coffee processing, with a focus on the research progress of technologies to control or reduce AA generation at different processing stages. Our study aims to provide different strategies for inhibiting AA formation during coffee processing and investigate related inhibition mechanisms.

Exploring correlations between green coffee bean components and thermal contaminants in roasted coffee beans

This study evaluated chemical compositions of green coffee beans from multi-production regions and correlated this information with thermal contaminants in roasted coffee. Using multivariate statistical techniques, formation of 5-hydroxymethylfurfural (5-HMF), furan, 2- and 3-methylfuran were positively correlated with lipid, sucrose, glutamic acid, phenylalanine, margaric acid, linolenic acid and trigonelline in green coffee beans. Moreover, significant positive correlations between acrylamide (AA) levels with aspartic acid, serine, alanine, histidine, asparagine, protein, and caffeine was found in green beans. Despite this, 5-HMF, furan, 2- and 3-methylfuran showed negative correlations with active constitutes (neochlorogenic acid, cryptochlorogenic acid, caffeine, total phenolics (TPC) and total flavonoids contents (TFC)), and several amino acids, and there were slight negative relationships between AA and myristic acid, palmitic acid, chlorogenic acid, sucrose, lipid, TPC and TFC. This study provides valuable enlightenment for the selection of proper coffee beans for production of coffee with high nutrition and low chemical hazardous risks.

Green Synthesized Zinc Oxide Nanoparticles Using Moringa olifera Ethanolic Extract Lessens Acrylamide-Induced Testicular Damage, Apoptosis, and Steroidogenesis-Related Gene Dysregulation in Adult Rats

This study assessed the possible protective role of green synthesized zinc oxide nanoparticles using Moringa olifera leaf extract (MO-ZNPs) in acrylamide (ACR)-induced reproductive dysfunctions in male rats. ACR (20 mg/kg b.wt/day) and/or MO-ZNPs (10 mg/kg b.wt/day) were given orally by gastric gavage for 60 days. Then, sperm parameters; testicular enzymes; oxidative stress markers; reproductive hormones including testosterone, luteinizing hormone (LH)-estradiol, and follicle-stimulating hormone (FSH) concentration; testis histology; steroidogenesis-related gene expression; and apoptotic markers were examined. The findings revealed that MO-ZNPs significantly ameliorated the ACR-induced decline in the gonadosomatic index and altered the pituitary-gonadal axis, reflected by decreased serum testosterone and FSH with increased estradiol and LH, and sperm analysis disruption. Furthermore, a notable restoration of the tissue content of antioxidants (catalase and reduced glutathione) but depletion of malondialdehyde was evident in MO-ZNPs+ACR-treated rats compared to ACR-exposed ones. In addition, MO-ZNPs oral dosing markedly rescued the histopathological changes and apoptotic caspase-3 reactions in the testis resulting from ACR exposure. Furthermore, in MO-ZNPs+ACR-treated rats, ACR-induced downregulation of testicular steroidogenesis genes and proliferating cell nuclear antigen (PCNA) immune-expression were reversed. Conclusively, MO-ZNPs protected male rats from ACR-induced reproductive toxicity by suppressing oxidative injury and apoptosis while boosting steroidogenesis and sex hormones.

Safest Roasting Times of Coffee To Reduce Carcinogenicity

ABSTRACT

Roasting coffee results in not only the creation of carcinogens such as acrylamide, furan, and polycyclic aromatic hydrocarbons but also the elimination of carcinogens in raw coffee beans, such as endotoxins, preservatives, or pesticides, by burning off. However, it has not been determined whether the concentrations of these carcinogens are sufficient to make either light or dark roast coffee more carcinogenic in a living organism. An Ames test was conducted on light, medium, and dark roast coffee from three origins. We found that lighter roast coffee shows higher mutagenicity, which is reduced to the control level in dark roast coffee varieties, indicating that the roasting process is not increasing mutagenic potential but is beneficial to eliminating the existing carcinogens in raw coffee beans. This result suggests that dark roast coffee is safer and promotes further studies of the various carcinogens in raw coffee that have been burned off.

HIGHLIGHTS

Acrylamide in widely consumed foods - a review

Acrylamide (AA) is considered genotoxic, neurotoxic and a 'probable human carcinogen'. It is included in group 2 A of the International Agency for Research on Cancer (IARC). The formation of AA occurs when starch-based foods are subjected to temperatures higher than 120 °C in an atmosphere with very low water content. The aim of this review is to shed light on the toxicological aspects of AA, showing its regulatory evolution, and describing the most interesting mitigation techniques for each food category involved, with a focus on compliance with EU legislation in the various classes of consumer products of industrial origin in Europe.

A novel single step solid-phase extraction combined with bromine derivatization method for rapid determination of acrylamide in coffee and its products by stable isotope dilution ultra-performance liquid chromatography tandem triple quadrupole electrospray ionization mass spectrometry

This work aimed to establish a novel determination method for acrylamide in coffee and its products by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acrylamide in samples were prepared by a single-step solid-phase extraction clean-up using mixed mode sorbents. The bromine derivatization efficiency of acrylamide and its internal standard were improved at an acidic condition. After derivation, the retention capability of acrylamide and its resistance to interference were significantly improved. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.2 and 4 μg/kg for roasted and instant coffees, while they were 0.24 and 0.8 μg/kg for ready-to-drink coffees. The average recoveries for acrylamide ranged from 99.3 to 102.2% in coffee and its products. All the results showed that the developed method was simple, quick, specific and suitable for screening and determination of acrylamide in batch samples of coffee and its products.

Investigation of thermal contaminants in coffee beans induced by roasting: A kinetic modeling approach

The roasting-induced formation of thermal contaminants in coffee beans, including 5-hydroxymethylfurfural (5-HMF), acrylamide (AA), furan (F), 2-methyl furan (2-MF), and 3-methyl furan (3-MF), was investigated using a kinetic modeling approach. Results showed that AA and 5-HMF formation and elimination occur simultaneously in coffee beans during roasting and that the related reactions follow first-order reaction kinetics. The concentrations of F, 2-MF, and 3-MF increased throughout the roasting experiment, and variations in the concentrations of these compounds during roasting could be best described by empirical, logistic model. The increase in weight loss and decrease in moisture content of the beans during roasting also displayed first-order reaction kinetics. High coefficients of determination (R² > 0.981) were observed for all fitted models, and the reaction rate constants of all models followed the Arrhenius law.

Evolution of microbial communities and nutritional content of fermented Amaranthus sp. leaves

Amaranth (Amaranthus sp.) is a promising indigenous leafy vegetable plant capable of contributing to food security in sub-Saharan Africa, thanks to its adaptability to diverse soils and its drought tolerance. Its edible parts such as leaves are characterized by high nutrient content. Food losses along the supply chain due to spoilage, however, especially of fresh produce is a challenge facing most of the sub-Saharan African countries in tackling food insecurity in the region. This calls for innovative yet inexpensive solutions such as natural fermentation to preserve the quality and safety of the commodity. To demonstrate the feasibility of natural fermentation in the preservation of vegetable amaranth, leaves were submerged (1:0.5 w/v) in distilled water with 3% sucrose and 3% NaCl dissolved. Control batches were prepared using only distilled water (1:0.5 w/v) with amaranth leaves. Samplings of both treated leaves and controls occurred at 0, 24, 48, 72, and 168 h to measure the pH and determine microbial population changes using culture and molecular-based techniques. Furthermore, the effects of treatment on nutritional content were assayed at the end of the process to determine the levels of B-group vitamins, β-carotene, lutein, and anti-nutrient phytic acid from unfermented fresh air-dried and 3% sucrose and 3% NaCl treated amaranth leaves. Finally, a visive and olfactive analysis was carried out to evaluate the acceptability of the final product. The significant drop of pH and the correct growth of Lactobacillaceae occurred only in treated batches, although Lactococcus was found in both treated and control samples. Furthermore, mean counts observed on selective media for controls and molecular high-throughput sequencing (HTS) analyses confirmed that in control samples, the undesired bacteria represented more than 60% of the microbial population. In treated amaranth leaves the amount of thiamin, riboflavin, vitamin B₆, β-carotene and lutein content were higher compared to the fresh unfermented air-dried leaves, and phytic acid content diminished after 7-days treatment. These findings suggest that treatment of amaranth leaves using 3% sucrose and 3% NaCl does not only preserve the commodity by arresting the growth of undesired microorganisms involved in spoilage and fosters the lactic acid bacteria but also improves the nutritional content of the fermented end product that has been warmly welcomed by panelists.

Acrylamide in non-centrifugal sugars and syrups

BACKGROUND

Acrylamide in foods has been widely studied because of its possible carcinogenicity. Most of the foods investigated were prepared using low moisture and high temperature conditions. Non-centrifugal sugars (NCSs), which have been promoted as 'non-chemical' natural sweeteners, contain precursors of acrylamide and their production processes involved prolonged heating. The acrylamide content in 32 commercial NCSs from coconut, cane and palmyra palm purchased in Asian countries was investigated. Additionally, syrups (80 ^o Brix) produced from coconut and palmyra raw saps and cane juice were prepared by evaporation with prolonged heating (2.5 h to reach 100 °C, 1 h to increase to 110 °C, held at 110 °C for 30 min). The compositions and contents of sugars, amino acids and minerals, as well as the physical characteristics of the raw saps, juice and syrups, were determined.

RESULTS

The acrylamide content of these 32 products ranged from < 15 to 4011 μg kg^-1 . The raw saps and juice were mildly acidic (pH 5.14-5.66) and similar values were observed for their syrups (4.73-5.73). The contents of sucrose, fructose and glucose in the saps and juice from these plants were similar, whereas their compositions varied with respect to amino acids. The variation of the ornithine content was significant, demonstrating a striking influence on the extent of acrylamide formation (867-1564 μg kg^-1 ) in the syrups prepared from these materials.

CONCLUSION

The present study emphasizes the importance of a careful monitoring and control of the critical steps invloved in the manufacturing process of NCSs (particularly the evaporation phase), aiming to protect the health and safety of consumers. © 2021 Society of Chemical Industry.

Heavy-Metal Contents and the Impact of Roasting on Polyphenols, Caffeine, and Acrylamide in Specialty Coffee Beans

The aim of this study was to determine the effect of roasting on the contents of polyphenols (PPH), acrylamide (AA), and caffeine (CAF) and to analyze heavy metals in specialty coffee beans from Colombia (COL) and Nicaragua (NIC). Samples of NIC were naturally processed and COL was fermented anaerobically. Green beans from COL (COL-GR) and NIC (NIC-GR) were roasted at two levels, light roasting (COL-LIGHT and NIC-LIGHT) and darker roasting (COL-DARK and NIC-DARK), at final temperatures of 210 °C (10 min) and 215 °C (12 min), respectively. Quantitative analyses of PPH identified caffeoylquinic acids (CQA), feruloylquinic acids, and dicaffeoylquinic acids. Isomer 5-CQA was present at the highest levels and reached 60.8 and 57.7% in COL-GR and NIC-GR, 23.4 and 29.3% in COL-LIGHT and NIC-LIGHT, and 18 and 24.2% in COL-DARK and NIC-DARK, respectively, of the total PPH. The total PPH contents were highest in COL-GR (59.76 mg/g dry matter, DM). Roasting affected the contents of PPH, CAF, and AA (p < 0.001, p < 0.011 and p < 0.001, respectively). Nickel and cadmium contents were significantly higher in the COL-GR than in the NIC-GR beans. Darker roasting decreased AA content, but light roasting maintained similar amounts of CAF and total PPH.

Fermentation as a tool for increasing food security and nutritional quality of indigenous African leafy vegetables: the case of Cucurbita sp

Sub-Saharan region is often characterized by food and nutrition insecurity especially "hidden hunger" which results from inadequate micronutrients in diets. African indigenous leafy vegetables (AILVs) can represent a valid food source of micronutrients, but they often go to waste resulting in post-harvest losses. In an attempt to prolong AILVs shelf-life while enhancing their nutritional quality, fermentation was studied from a microbiological and nutritional point of view. Pumpkin leaves (Cucurbita sp.) were spontaneously fermented using the submerged method with 3% NaCl and 3% sucrose. Controls were set up, consisting of leaves with no additions. During fermentation, samples of both treatments were taken at 0, 24, 48, 72 and 168 h to monitor pH and characterize the microbial population through culture-based and molecular-based analyses. Variations between fresh and treated leaves in B-group vitamins, carotenoids, polyphenols, and phytic acid were evaluated. Data revealed that the treatment with addition of NaCl and sucrose hindered the growth of undesired microorganisms; in controls, unwanted microorganisms dominated the bacterial community until 168 h, while in treated samples Lactobacillaceae predominated. Furthermore, the content in folate, β-carotene and lutein increased in treated leaves compared to the fresh ones, while phytic acid diminished indicating an amelioration in the nutritional value of the final product. Thus, fermentation could help in preserving Cucurbita sp. leaves, avoiding contamination of spoilage microorganisms and enhancing the nutritional values.

Differential colorimetric nanobiosensor array as bioelectronic tongue for discrimination and quantitation of multiple foodborne carcinogens

Foodborne amides, specifically acrylamide, are vitally important for food safety and security, as they are the most common food toxicants and suspected human carcinogens. A facile and novel differential-based colorimetric nanobiosensor array composed of three surface-bioengineered gold nanoparticles (AuNPs) was developed for the rapid detection, differentiation, and quantification of acrylamide and six analogues. Diverse cross-reactive receptors demonstrated differential binding affinities toward target analytes, resulting in distinctive AuNP aggregation behaviors and distinguishable response patterns. The sensor array, integrated with principal component analysis and hierarchical cluster analysis, accurately discriminated foodborne amides based on their amine subgroups, International Agency for Research on Cancer (IARC) carcinogen classifications, and food additive types, even at ultra-low concentrations (500 pM). Additionally, the sensor array successfully differentiated non-targeted analytes by sweetener and food ingredients types with 100% correct classification. Partial least squares regression outcomes exhibited high correlation coefficients (R2 > 0.95). Thus, the sensor array has practical potential for food safety monitoring in the food and beverage industries.

Chemical characterization of Wuyi rock tea with different roasting degrees and their discrimination based on volatile profiles

Wuyi rock tea is a typical and famous oolong tea in China and roasting is an important manufacturing procedure for its flavor formation. This work aimed to explore the effect of roasting on non-volatiles and volatiles of 12 Wuyi rock tea samples at three roasting levels (low, moderate and sufficient), made from four tea cultivars (Shuixian, Qizhong, Dahongpao, Rougui). Results show that different roasting had not caused significant difference on contents of soluble solids, total polyphenols, flavonoids, soluble sugar, thearubigins and theabrownins, while it slightly regulated caffeine, proteins and theaflavins, and remarkably reduced catechins and free amino acids. The ratio of polyphenol content/amino acid content, a negative-correlated indicator of fresh and brisk taste, significantly increased with the increase of roasting degree. High-level roasting not only decreased the fresh and brisk taste of the tea infusion, but also reduced the amount of bioactive ingredients including catechins and theanine. A total of 315 volatiles were detected and analyzed with OPLS-DA and HCA methods, in which 99 volatiles were found with variable importance in the projection (VIP) values greater than 1.00. Tea samples at different roasting degrees were successfully separated by this model of roasting-level discrimination. 'Naphthalene, 1,2,3,4-tetrahydro-1,6,8-trimethyl-', '1,1,5-trimethyl-1,2-dihydronaphthalene', 'p-Xylene', 'alpha.-methyl-.alpha.-[4-methyl-3-pentenyl]oxiranemethanol', 'hydrazinecarboxylic acid, phenylmethyl ester', and '3-buten-2-one, 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-' might be key characteristic markers for the roasting process of Wuyi rock tea.

Physicochemical characteristics of Ethiopian Coffea arabica cv. Heirloom coffee extracts with various roasting conditions

This study aimed to investigate the physicochemical characteristics of Ethiopian Coffea arabica cv. Heirloom coffee extracts with various roasting conditions. Green coffee beans were roasted at four different conditions (Light-medium, Medium, Moderately dark, and Very dark) and used to extract espresso and drip coffee. Moisture content in coffee beans was decreased as the roasting degree increased. The contents of crude fat and ash were lower in the Light-medium roasted coffee beans than in green coffee beans but increased as the roasting degree increased. The values of lightness (L^*), redness (a^*), yellowness (b^*), and browning index of coffee extracts were decreased as the roasting degree increased. Total dissolved solids in espresso coffee were increased with increasing roasting degree but decreased in drip coffee. In both the extracts, the contents of reducing sugar, titratable acidity, organic acids, and chlorogenic acid were decreased, but that of caffeine was increased with the roasting degree increased.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-020-00865-w.

Selection of Vegetable Oils and Frying Cycles Influencing Acrylamide Formation in the Intermittently Fried Beef Nuggets

This study aims to investigate the effect of different vegetable oils and frying cycles on acrylamide formation during the intermittent frying of beef nuggets. Different vegetable oils, palm olein (PO), red palm olein (RPO), sunflower oil (SFO), and soybean oil (SBO), were used for a total of 80 frying cycles. Oil was collected at every 16th frying cycle and analyzed for peroxide value (PV), p-anisidine value (p-AV), free fatty acid (FFA), total polar compound (TPC), polar compound fractions, and fatty acid composition (FAC). Total oxidation (TOTOX) value was calculated, and acrylamide content was quantified in the nuggets. Regardless of the oil type, PV, p-AV, and TOTOX initially increased but gradually decreased. However, FFA and TPC continued to develop across the 80 frying cycles. The C18:2/C16:0 remained almost unchanged in PO and RPO but dropped progressively in SFO and SBO. The lowest acrylamide content in fried products was observed in the PO, while the highest content was observed in RPO. Bivariate correlation analysis showed no significant (p ≤ 0.05) correlation between oil quality attributes and acrylamide concentration. The oil type but not the frying cycle significantly affected the acrylamide concentration in beef nuggets.

An overview of conventional and emerging techniques of roasting: Effect on food bioactive signatures

Roasting is a food processingtechnique that employs the principle of heating to cook the product evenly and enhance the digestibility, palatability and sensory aspects of foods with desirable structural modifications of the food matrix. With the burgeoning demand for fortified roasted products along with the concern for food hygiene and the effects of harmful compounds, novel roasting techniques, and equipment to overcome the limitations of conventional operations are indispensable. Roasting techniques employing microwave, infrared hot-air, superheated steam, Revtech roaster, and Forced Convection Continuous Tumble (FCCT) roasting have been figuratively emerging to prominence for effectively roasting different foods without compromising the nutritional quality. The present review critically appraises various conventional and emerging roasting techniques, their advantages and limitations, and their effect on different food matrix components, functional properties, structural attributes, and sensory aspects for a wide range of products. It was seen that thermal processing at high temperatures for increased durations affected both the physicochemical and structural properties of food. Nevertheless, novel techniques caused minimum destructive impacts as compared to the traditional processes. However, further studies applying novel roasting techniques with a wide range of operating conditions on different types of products are crucial to establish the potential of these techniques in obtaining safe, quality foods.

Bioactive compounds, antioxidant activity and antiproliferative effects in prostate cancer cells of green and roasted coffee extracts obtained by microwave-assisted extraction (MAE)

Coffee consumption has been investigated as a protective factor against prostate cancer. Coffee may be related to prostate cancer risk reduction due to its phytochemical compounds, such as caffeine, chlorogenic acids, and trigonelline. The roasting process affects the content of the phytochemicals and undesired compounds can be formed. Microwave-assisted extraction is an alternative to conventional extraction techniques since it preserves more bioactive compounds. Therefore, this study aimed to evaluate the phytochemical composition and the putative preventive effects in prostate cancer development of coffee beans submitted to four different coffee-roasting degrees extracted using microwave-assisted extraction. Coffea arabica green beans (1) were roasted into light (2), medium (3) and dark (4) and these four coffee samples were submitted to microwave-assisted extraction. The antioxidant capacity of these samples was evaluated by five different methods. Caffeine, chlorogenic acid and caffeic acid were measured through HPLC. Samples were tested against PC-3 and DU-145 metastatic prostate cancer cell lines regarding their effects on cell viability, cell cycle progression and apoptotic cell death. We found that green and light roasted coffee extracts had the highest antioxidant activity. Caffeine content was not affected by roasting, chlorogenic acid was degraded due to the temperature, and caffeic acid increased in light roasted and decreased in medium and dark roasted. Green and light roasted coffee extracts promoted higher inhibition of cell viability, caused greater cell cycle arrest in S and G₂/M and induced apoptosis more compared to medium and dark roasted coffee extracts and the control samples. Coffee extracts were more effective against DU-145 than in PC-3 cells. Our data provide initial evidence that among the four tested samples, the consumption of green and light coffee extracts contributes to inhibit prostate cancer tumor progression features, potentially preventing aspects related to advanced prostate cancer subtypes.

Molecularly imprinted photoelectrochemical sensing based on ZnO/polypyrrole nanocomposites for acrylamide detection

A highly sensitive quenching molecular imprinting (MIP) photoelectrochemical (PEC) sensor was proposed to detect acrylamide (AM) by using the photoactive composite of ZnO and polypyrrole (PPy) as the PEC signal probe. ZnO, with high electron mobility, excellent chemical and thermal stability as well as good biocompatibility, was selected as the photoelectrically active material. A polypyrrole film was formed on the nanodisk ZnO by electrochemical polymerization, and the recognition site of AM was left on the surface of the PPy film by elution, enabling the specific detection of AM. The transfer of electrons will be hindered when AM is adsorbed on the ZnO/PPy nanocomposites surface, which results in the decrease of photocurrent signal. The proposed molecularly imprinted PEC sensor exhibits significant detection performance of AM in the range of 10-1 M-2.5 × 10-9 M with a LOD of 2.147 × 10-9 M (S/N = 3). The use of photoelectrochemical technology combined with molecular imprinting technology enables the PEC sensor to have excellent selectivity, superior repeatability, preferable stability, low cost, and easy construction, providing a new method for the detection of AM. The high recovery rate in the detection of real samples of potato chips and biscuits indicates that the proposed PEC sensor has potential in monitoring the emerging food safety risks.

Acrylamide formation and antioxidant activity in coffee during roasting - A systematic study

The aim of this study was to investigate the effect of the coffee roasting process on both toxic and some beneficial antioxidant compounds, applying a systematic and broad approach. Arabica and Robusta green coffee beans were roasted in a lab-scale roaster for different times in order to achieve five roasting degrees (from light to dark) and to assess the evolution of acrylamide (AA), trigonelline, nicotinic acid and caffeoylquinic acids contents (determined by HPLC) as well as antioxidant activity (evaluated by Folin-Ciocalteu, FRAP, DPPH, ABTS assays). The results confirmed that the AA levels and antioxidant activity reached a maximum in the first coffee roasting degrees and then decreased prolonging the heating process, both in Arabica and Robusta samples. Nevertheless, the thermal reduction observed was greater for AA compared to antioxidant activity, which was only slightly reduced due to the balance between the degradation and the neoformation of antioxidant compounds.

Coffee in cancer chemoprevention: an updated review

INTRODUCTION

Chemoprevention of cancer refers to the use of natural or synthetic compounds to abolish or perturb a variety of steps in tumor initiation, promotion, and progression. This can be realized through different mechanisms, including activation of free radical scavenging enzymes, control of chronic inflammation, and downregulation of specific signaling pathways.

AREAS COVERED

The goal of this article is to critically review recent evidence on association between coffee and prevention of different types of cancer, with particular emphasis on the molecular mechanisms and the bioactive compounds involved in its anticancer activity.

EXPERT OPINION

Coffee is a mixture of different compounds able to decrease the risk of many types of cancer. However, its potential anticancer activity is not completely understood. Hundreds of biologically active components such as caffeine, chlorogenic acid, diterpenes are contained in coffee. Further research is needed to fully elucidate the molecular mechanisms underlying the anticancer effects of coffee and fully understand the role of different confounding factors playing a role in its reported anticancer activity.

Identification of Acrylamide Adducts Generated during Storage of Canned Milk Coffee

Since coffee is a significant contributor to the consumption of acrylamide, its reduction is required. Acrylamide is produced during the roasting of coffee beans, but the roasting process is an essential step in determining the taste of coffee. Acrylamide content in coffee has been suggested to decrease by reacting with proteins and/or other substances during storage, but details are unknown. Investigation of acrylamide adducts may contribute to a strategy for acrylamide reduction in coffee. In this study, a stable isotope labeling technique, combined with high-resolution mass spectrometry, allows the identification of acrylamide adducts (3-hydroxypyridine-acrylamide and pyridine-acrylamide) in canned milk coffee. Other acrylamide adducts derived from milk coffee proteins, Lys-acrylic acid and CysSO₂-acrylic acid, were identified. During a 4-month storage period, the formation of these four adducts was found to reduce the total content of acrylamide by 75.3% in canned milk coffee. Therefore, endogenous proteins can be used in acrylamide reduction.

Processing effects on acrylamide content in roasted coffee production

Acrylamide is a toxic compound that develops during the roasting process of coffee beans. According to literature, the levels of acrylamide in coffee vary with the percentage of Robusta type in the mix and with the time-temperature parameters during the roasting process. Therefore, this study aimed to find the best roasting conditions in order to mitigate acrylamide formation. Two types of roasted coffee (Arabica and Robusta) were analyzed through GC-MS and two clean-up methods were compared. The best roasting conditions were optimized on an industrial scale and the median levels of acrylamide decreased from the range 170-484 µg kg^-1 to 159-351 µg kg^-1, after the optimization of roasting parameters. Therefore, the choice of the best conditions, according to the percentage of Robusta type in the finished product, could be an efficient mitigation strategy for acrylamide formation in coffee, maintaining the manufacturer's requirements of the finished product.

Acrylamide in coffee: formation and possible mitigation strategies - a review

It is widely known that acrylamide, present in some different heat-treated foods, is an important toxic compound to humans. Coffee beverage is one of the most important sources of acrylamide, because the raw bean contains the reaction substrates and it is processed at very high temperature during roasting. Due to its high consumption all over the world, it is necessary to find applicable solutions to decrease the concentration of this undesired Maillard reaction product.The present review summarizes the advance made in understanding the acrylamide formation and describes the potential acrylamide reduction strategies along all coffee production steps, from raw material to coffee brew preparation with a dominant focus on roasting stage.Currently, it is quite established that the selection of the highest quality Arabica green coffee variety, high roasting thermal input and shortest brewing techniques lead to low final acrylamide levels. There are also few innovative interventions proposed for acrylamide control in coffee such as enzymatic treatments of raw material, vacuum or steam roasting, roasted beans supercritical fluid extraction, final beverage treatments like yeast fermentation and amino acids/additive additions. However, for these strategies the impact on the desired sensorial and nutritional coffee brew properties must be evaluated and some proposed procedures are still difficult to be applied at real industrial scale. Furthermore, in-depth studies are needed in order to find appropriate and practical solutions for acrylamide mitigation in coffee with a holistic risk/benefit approach.