Effects of high-pressure processing on fungi spores: Factors affecting spore germination and inactivation and impact on ultrastructure

Effect of antifungal proteins (AFPs) on the viability of heat-resistant fungi (HRFs) and the preservation of fruit juices

The control of heat-resistant fungi (HRFs), which cause spoilage of heat-treated fruit products, is considered a challenge for the fruit juice and beverage industry and requires new strategies for the development of antifungal compounds. In this study, four antifungal proteins (AFPs) from Penicillium digitatum (PdAfpB) and Penicillium expansum (PeAfpA, PeAfpB and PeAfpC), were evaluated against conidia from a representative collection of HRFs. A total of 19 strains from 16 different species belonging to the genera Aspergillus, Hamigera, Paecilomyces, Rasamsonia, Sarocladium, Talaromyces and Thermoascus were included in the study. PeAfpA and PdAfpB exhibited potent antifungal activity in synthetic media, completely inhibiting the growth of most of the fungi evaluated in the range of 0.5-32 μg/mL. The efficacy of the four AFPs was also tested in fruit juices against ascospores of five HRFs relevant to the food industry, including P. fulvus, P. niveus, P. variotii, A. fischeri and T. flavus. PdAfpB was the most effective protein in fruit juices, since it completely inhibited the growth of the five species tested in at least one of the fruit juices evaluated. This is the first study to demonstrate the activity of AFPs against fungal ascospores. Finally, a challenge test study showed that PdAfpB, at a concentration of 32 μg/mL, protected apple fruit juice artificially inoculated with ascospores of P. variotii for 17 days, highlighting the potential of the protein as a preservative in the fruit juice industry.

High-pressure processing and heat treatment of Murrah buffalo milk: Comparative study on microbial changes during refrigerated storage

This study aims to evaluate the effect of high-pressure processing (HPP) (500 and 600 MPa for 3 min and 5 min) on the microbial changes of Murrah buffalo milk in comparison to heat treatment (72 °C for 15 s of holding time) during refrigerated storage of 28 days. The results indicated that the total plate count (TPC) of raw milk at day 0 was 5.5 ± 0.6 log10 CFU/mL. At day 0, heat treatment lowered TPC to 3.9 ± 0.6, while HPP treatment was in the range of 4.1 ± 0.3 to 4.8 ± 0.6 log10 CFU/mL. Similarly, lowered yeast and mold count and lactic acid bacteria were noted in heat- and HPP-treated milk samples compared to the control sample during refrigerated storage. There were no Staphylococcus aureus and Escherichia coli detected in heat and HPP-treated samples. Heat or HPP treatment at 600 MPa for 5 min significantly extended the shelf-life of Murrah buffalo milk for three weeks at the refrigerated storage. In addition, HPP treatment did not alter the pH, lightness (L* value), protein, or fat content of Murrah buffalo milk during refrigerated storage. Hence HPP at 600 MPa for 5 min could be a suitable alternative to conventional heat treatment.

Critical impact of pressure regulation on carbon dioxide biosynthesis

Carbon dioxide (CO2) biosynthesis is a promising alternative to traditional chemical synthesis. However, its application in engineering is hampered by poor gas mass transfer rates. Pressurization is an effective method to enhance mass transfer and increase synthesis yield, although the underlying mechanisms remain unclear. This review examines the effects of high pressure on CO2 biosynthesis, elucidating the mechanisms behind yield enhancement from three perspectives: microbial physiological traits, gas mass transfer and synthetic pathways. The critical role of pressurization in improving microbial activity and gas transfer efficiency is emphasized, with particular attention to maintaining pressure within microbial tolerance limits to maximize yield without compromising cell structure integrity.

Novel insights into dimethylsulfoniopropionate cleavage by deep subseafloor fungi

Dimethylsulfoniopropionate (DMSP), a key organic sulfur compound in marine and subseafloor sediments, is degraded by phytoplankton and bacteria, resulting in the release of the climate-active volatile gas dimethylsulfide (DMS). However, it remains unclear if dominant eukaryotic fungi in subseafloor sediments possess specific abilities and metabolic mechanisms for DMSP degradation and DMS formation. Our study provides the first evidence that fungi from coal-bearing sediments ∼2 km below the seafloor, such as Aspergillus spp., Chaetomium globosum, Cladosporium sphaerospermum, and Penicillium funiculosum, can degrade DMSP and produce DMS. In Aspergillus sydowii 29R-4-F02, which exhibited the highest DMSP-dependent DMS production rate (16.95 pmol/μg protein/min), two DMSP lyase genes, dddP and dddW, were identified. Remarkably, the dddW gene, previously observed only in bacteria, was found to be crucial for fungal DMSP cleavage. These findings not only extend the list of fungi capable of degrading DMSP, but also enhance our understanding of DMSP lyase diversity and the role of fungi in DMSP decomposition in subseafloor sedimentary ecosystems.

High pressure pasteurization: Simultaneous native tissue decellularization and sterilization

Introduction

Terminal sterilization is important for the clinical applicability of decellularized xenografts. High hydrostatic pressurization (HHP) process is a potential strategy for decellularization and decontamination of xenografts; however, its disinfection efficiency remains poorly elucidated. This study investigated the disinfection efficacy of the HHP process at physiologically relevant 36 °C against difficult-to-kill spore-forming bacteria.

Methods

Bacillus atrophaeus and Geobacillus stearothermophilus were suspended in a pressurization medium with or without antibiotic agents and pressurized under two different HHP procedures: repeated and sustained pressurization.

Results

The sustained pressurizing conditions, exploited for the conventional tissue decellularization, did not effectively eliminate the bacteria; however, repeated pressurization greatly increased the disinfection effect. Moreover, the antibiotic-containing pressurization medium further increased the disinfection efficiency to the level required for sterilization.

Conclusions

The optimized high hydrostatic pressurization can be used to sterilize biological tissues during the decellularization process and is a promising strategy for manufacturing tissue-derived healthcare products.

Ultrasonication for honey processing and preservation: A brief overview

Honey is a food product consumed all over the world. Besides its nutritional properties, honey presents antibacterial, antioxidant, and wound-healing properties. To ensure that the final product meets qualitative and microbiological standards, honey treatment is of great importance. Conventional honey treatment is based on the heating of honey samples for decrystallization and bacteria and yeast inactivation. However, conventional heating can cause negative effects on honey quality, such as the formation of toxic compounds, reduction of enzyme activity, and loss of antioxidant and antimicrobial properties. The application of ultrasonic waves has demonstrated interesting effects on honey processing. Ultrasound (US) treatment can lead to the fragmentation of glucose crystals in crystalized honey and has little effect on its properties. In addition to inactivating microorganisms, US-assisted honey processing also preserves phenolic compounds content and antimicrobial properties. However, there is still limited information about honey sonication. The aim of the present review is to comprehensively show the possibilities of US application in honey processing and its effects on honey properties.

High Pressure and Pasteurization Effects on Dairy Cream

Dairy cream, a common ingredient in various dishes and food products, is susceptible to rapid microbial growth due to its high water activity (≈0.97) and pH (≈6.7). Thus, it requires proper processing conditions to ensure food safety and extend shelf life. High-pressure processing (HPP) has emerged as a nonthermal food pasteurization method, offering an alternative to conventional heat-based techniques to obtain tastier, fresh-like, and safe dairy products without undesirable heat-induced alterations. This study assessed the impact of HPP (450 and 600 MPa for 5 and 15 min at 7 °C) and thermal pasteurization (75 °C for 15 s) on the microbiological and physicochemical attributes of dairy cream immediately after processing and throughout refrigerated storage (4 °C). HPP-treated samples remained microbiologically acceptable even on the 51st day of storage, unlike thermally pasteurized samples. Moreover, HPP decreased inoculated Escherichia coli and Listeria innocua counts by more than 6 log units to undetectable levels (1.00 log CFU/mL). pH, color (maximum variation of ΔE* up to 8.43), and fatty acid profiles remained relatively stable under varying processing conditions and during storage. However, viscosity exhibited higher values for HPP-treated samples (0.028 ± 0.003 Pa·s) compared to thermally processed ones (0.016 ± 0.002 Pa·s) by the 28th day of storage. Furthermore, volatile compounds (VOCs) of all treated samples presented a tendency to increase throughout storage, particularly acids and aliphatic hydrocarbons. These findings show HPP's potential to significantly extend the shelf life of highly perishable dairy cream by at least 15 days compared to thermal pasteurization.

Nano and Technological Frontiers as a Sustainable Platform for Postharvest Preservation of Berry Fruits

Berries are highly perishable and susceptible to spoilage, resulting in significant food and economic losses. The use of chemicals in traditional postharvest protection techniques can harm both human health and the environment. Consequently, there is an increasing interest in creating environmentally friendly solutions for postharvest protection. This article discusses various approaches, including the use of "green" chemical compounds such as ozone and peracetic acid, biocontrol agents, physical treatments, and modern technologies such as the use of nanostructures and molecular tools. The potential of these alternatives is evaluated in terms of their effect on microbial growth, nutritional value, and physicochemical and sensorial properties of the berries. Moreover, the development of nanotechnology, molecular biology, and artificial intelligence offers a wide range of opportunities to develop formulations using nanostructures, improving the functionality of the coatings by enhancing their physicochemical and antimicrobial properties and providing protection to bioactive compounds. Some challenges remain for their implementation into the food industry such as scale-up and regulatory policies. However, the use of sustainable postharvest protection methods can help to reduce the negative impacts of chemical treatments and improve the availability of safe and quality berries.

High-pressure pulses for Aspergillus niger spore inactivation in a model pharmaceutical lipid emulsion

High hydrostatic pressure (HHP) is a non-thermal process widely used in the food industry to reduce microbial populations. However, rarely its effect has been assessed in products with high oil content. This study evaluated the efficacy of HHP (200, 250, and 300 MPa) at different temperatures (25, 35, and 45 °C) by cycles (1, 2, or 3) of 10 min in the inactivation of Aspergillus niger spores in a lipid emulsion. After treatments at 300 MPa for 1 cycle at 35 or 45 °C, no surviving spores were recovered. All treatments were modeled by the linear and Weibull models. The presence of shoulders and tails in the treatments at 300 MPa at 35 or 45 °C resulted in sigmoidal curves which cannot be described by the linear model, hence the Weibull + Tail, Shoulder + Log-lin + Tail, and double Weibull models were evaluated to elucidate the inactivation kinetics. The tailing formation could be related to the presence of resistance subpopulations. The double Weibull model showed better goodness of fit (RMSE <0.2) to describe the inactivation kinetics of the treatments with the higher spore reductions. HHP at 200-300 MPa and 25 °C did not reduce the Aspergillus niger spores. The combined HHP and mild temperatures (35-45 °C) favored fungal spore inactivation. Spore inactivation in lipid emulsions by HHP did not follow a linear inactivation. HHP at mild temperatures is an alternative to the thermal process in lipid emulsions.

Comparison of high pressure and thermal pasteurization on the quality parameters of strawberry products: a review

Strawberry (Fragaria ananassa) is rich in bioactive compounds with high antioxidant activity. High pressure processing (HPP) is an efficient alternative to preserve these bioactive compounds in terms of microbial inactivation and shelf-life stability. This review compares the effects of pasteurization methods using high pressure or thermal pasteurization (TP) on the quality parameters of various strawberry-based products. To summarize, most of the high pressure-treated products are microbiologically stable and showed minimum degradation of thermolabile compounds than TP-treated ones. However, some studies reported that high pressure did not have an advantage over TP especially in the preservation of phenolic phytochemicals during storage. The insufficient enzyme inactivation and high residual activity of enzymes after high pressure treatment could cause anthocyanins degradation thus affecting the product quality. Overall, this review could be valuable to potential processors in evaluating the effective commercialization of high pressure-treated strawberry products.

Development Control and Inactivation of Byssochlamys nivea Ascospores by Hyperbaric Storage at Room Temperature

This study tested hyperbaric storage (25-150 MPa, for 30 days) at room-temperature (HS/RT, 18-23 °C) in order to control the development of Byssochlamys nivea ascospores in apple juice. In order to mimic commercially pasteurized juice contaminated with ascospores, thermal pasteurization (70 and 80 °C for 30 s) and nonthermal high pressure pasteurization (600 MPa for 3 min at 17 °C, HPP) took place, and the juice was afterwards placed under HS/RT conditions. Control samples were also placed in atmospheric pressure (AP) conditions at RT and were refrigerated (4 °C). The results showed that HS/RT, in samples without a pasteurization step and those pasteurized at 70 °C/30 s, was able to inhibit ascospore development, contrarily to samples at AP/RT and refrigeration. HS/RT for samples pasteurized at 80 °C/30 s evidenced ascospore inactivation, especially at 150 MPa, wherein an overall reduction of at least 4.73 log units of ascospores was observed to below detection limits (1.00 Log CFU/mL); meanwhile, for HPP samples, especially at 75 and 150 MPa, an overall reduction of 3 log units (to below quantification limits, 2.00 Log CFU/mL) was observed. Phase-contrast microscopy revealed that the ascospores do not complete the germination process under HS/RT, hence avoiding hyphae formation, which is important for food safety since mycotoxin development occurs only after hyphae formation. These findings suggest that HS/RT is a safe food preservation methodology, as it prevents ascospore development and inactivates them following commercial-like thermal or nonthermal HPP pasteurization, preventing mycotoxin production and enhancing ascospore inactivation.

High-Pressure-Based Strategies for the Inactivation of Bacillus subtilis Endospores in Honey

Honey is a value-added product rich in several types of phenolic compounds, enzymes, and sugars recently explored in biomedical and food applications. Nevertheless, even though it has a low water activity (a_W ≈ 0.65) that hinders the development of pathogenic and spoilage microorganisms, it is still prone to contamination by pathogenic microorganisms (vegetative and spores) and may constitute harm to special groups, particularly by immunosuppressed people and pregnant women. Thus, an efficient processing methodology needs to be followed to ensure microbial safety while avoiding 5-hydroxymethylfurfural (HMF) formation and browning reactions, with a consequent loss of biological value. In this paper, both thermal (pressure-assisted thermal processing, PATP) and nonthermal high-pressure processing (HPP), and another pressure-based methodology (hyperbaric storage, HS) were used to ascertain their potential to inactivate Bacillus subtilis endospores in honey and to study the influence of a_W on the inactivation on this endospore. The results showed that PATP at 600 MPa/15 min/75 °C of diluted honey (52.9 °Brix) with increased a_W (0.85 compared to ≈0.55, the usual honey a_W) allowed for inactivating of at least 4.0 log units of B. subtilis spores (to below detection limits), while HS and HPP caused neither the germination nor inactivated spores (i.e., there was neither a loss of endospore resistance after heat shock nor endospore inactivation as a consequence of the storage methodology). PATP of undiluted honey even at harsh processing conditions (600 MPa/15 min/85 °C) did not impact the spore load. The results for diluted honey open the possibility of its decontamination by spores’ inactivation for medical and pharmaceutical applications.

Inactivating Food Microbes by High-Pressure Processing and Combined Nonthermal and Thermal Treatment: A Review

High-pressure processing (HPP) is a mild technology alternative to thermal pasteurization and sterilization of different food products. HPP has emerged to provide enormous benefits to consumers, i.e., mildly processed food and additive-free food. It effectively retains bioactive compounds and extends the shelf life of food commodities by inactivating bacteria, yeast, mold, and virus. The limitation of HPP in inactivating spores can be overcome by using other thermal and nonthermal processing sequentially or simultaneously with HPP. This review summarizes the applications of HPP in the fruits and vegetables, dairy, meat, fish, and poultry sector. It also emphasizes microbial food safety and the effectiveness of HPP in the load reduction of microorganisms. Comprehensive information about the synergistic effect of HPP with different techniques and their effectiveness in ensuring food safety is reported. The summarized data would be handy to interested researchers and industry personnel.

Effect of High Pressure on the Properties of Chocolate Fillings during Long-Term Storage

The aim of this study was to evaluate the impact of high-pressure processing (HPP) on the long-term storage of chocolate fillings at room temperature, compared with conventional storage at lower temperatures. Dark chocolate fillings were treated at different pressure levels, holding times and stored at 20 °C for 12 months. Unprocessed batches were stored at 4 °C and at −12 °C. Moisture, water activity (aw), pH, colour, G′_1Hz and indigenous microflora were measured at 2, 4, 6, 8, 10 and 12 months of storage. Results showed that 600 MPa/20 min processing was the most effective controlling mesophilic group, presenting 3.8 log cfu/g after 12 months of storage, and inactivating moulds and yeasts after HPP treatment. Colour was affected by storage, including a reduction in the L* parameter in all conditions to final values between 37.8 and 39.3, while the a* parameter increased during storage time at −12 °C and 4 °C to final values of around 12, and parameter b* decreased at storage temperature 20 °C to 5.3. Storage time affected the rheological behaviour of HPP-treated samples, increasing G′_1Hz from the 2nd to 12th month of storage time to the final values between 1603 kPa and 2139 kPa. Moisture, aw and pH were not affected by HPP treatment nor storage time.

Conventional and emergent technologies for honey processing: A perspective on microbiological safety, bioactivity, and quality

Honey is a natural food of worldwide economic importance. Over the last decades, its potential for food, medical, cosmetical, and biotechnological applications has been widely explored. One of the major safety issues regarding such applications is its susceptibility to being contaminated with bacterial and fungi spores, including pathogenic ones, which may impose a hurdle to its consumption in a raw state. Another factor that makes this product particularly challenging relies on its high sugar content, which will lead to the formation of hydroxymethylfurfural (HMF) when heated (due to Maillard reactions). Moreover, honey's bioactivity is known to be affected when it goes through thermal processing due to its unstable and thermolabile components. Therefore, proper food processing methodologies are of utmost importance not only to ensure honey safety but also to provide a high-quality product with low content of HMF and preserved biological properties. As so, emerging food processing technologies have been employed to improve the safety and quality of raw honey, allowing, for example, to reduce/avoid the exposure time to high processing temperatures, with consequent impact on the formation of HMF. This review aims to gather the literature available regarding the use of conventional and emergent food processing technologies (both thermal and nonthermal food processing technologies) for honey decontamination, preservation/enhancement of honey biological activity, as well as the sensorial attributes.

Spore Germination of the Obligate Biotroph Spongospora subterranea: Transcriptome Analysis Reveals Germination Associated Genes

For soilborne pathogens, germination of the resting or dormant propagule that enables persistence within the soil environment is a key point in pathogenesis. Spongospora subterranea is an obligate soilborne protozoan that infects the roots and tubers of potato causing root and powdery scab disease for which there are currently no effective controls. A better understanding of the molecular basis of resting spore germination of S. subterranea could be important for development of novel disease interventions. However, as an obligate biotroph and soil dwelling organism, the application of new omics techniques for the study of the pre-infection process in S. subterranea has been problematic. Here, RNA sequencing was used to analyse the reprogramming of S. subterranea resting spores during the transition to zoospores in an in-vitro model. More than 63 million mean high-quality reads per sample were generated from the resting and germinating spores. By using a combination of reference-based and de novo transcriptome assembly, 6,664 unigenes were identified. The identified unigenes were subsequently annotated based on known proteins using BLAST search. Of 5,448 annotated genes, 570 genes were identified to be differentially expressed during the germination of S. subterranea resting spores, with most of the significant genes belonging to transcription and translation, amino acids biosynthesis, transport, energy metabolic processes, fatty acid metabolism, stress response and DNA repair. The datasets generated in this study provide a basic knowledge of the physiological processes associated with spore germination and will facilitate functional predictions of novel genes in S. subterranea and other plasmodiophorids. We introduce several candidate genes related to the germination of an obligate biotrophic soilborne pathogen which could be applied to the development of antimicrobial agents for soil inoculum management.

Evolving challenges and strategies for fungal control in the food supply chain

Fungi that spoil foods or infect crops can have major socioeconomic impacts, posing threats to food security. The strategies needed to manage these fungi are evolving, given the growing incidence of fungicide resistance, tightening regulations of chemicals use and market trends imposing new food-preservation challenges. For example, alternative methods for crop protection such as RNA-based fungicides, biocontrol, or stimulation of natural plant defences may lessen concerns like environmental toxicity of chemical fungicides. There is renewed focus on natural product preservatives and fungicides, which can bypass regulations for 'clean label' food products. These require investment to find effective, safe activities within complex mixtures such as plant extracts. Alternatively, physical measures may be one key for fungal control, such as polymer materials which passively resist attachment and colonization by fungi. Reducing or replacing traditional chlorine treatments (e.g. of post-harvest produce) is desirable to limit formation of disinfection by-products. In addition, the current growth in lower sugar food products can alter metabolic routing of carbon utilization in spoilage yeasts, with implications for efficacy of food preservatives acting via metabolism. The use of preservative or fungicide combinations, while involving more than one chemical, can reduce total chemicals usage where these act synergistically. Such approaches might also help target different subpopulations within heteroresistant fungal populations. These approaches are discussed in the context of current challenges for food preservation, focussing on pre-harvest fungal control, fresh produce and stored food preservation. Several strategies show growing potential for mitigating or reversing the risks posed by fungi in the food supply chain.

Critical Assessment of Mycotoxins in Beverages and Their Control Measures

Mycotoxins are secondary metabolites of filamentous fungi that contaminate food products such as fruits, vegetables, cereals, beverages, and other agricultural commodities. Their occurrence in the food chain, especially in beverages, can pose a serious risk to human health, due to their toxicity, even at low concentrations. Mycotoxins, such as aflatoxins (AFs), ochratoxin A (OTA), patulin (PAT), fumonisins (FBs), trichothecenes (TCs), zearalenone (ZEN), and the alternaria toxins including alternariol, altenuene, and alternariol methyl ether have largely been identified in fruits and their derived products, such as beverages and drinks. The presence of mycotoxins in beverages is of high concern in some cases due to their levels being higher than the limits set by regulations. This review aims to summarize the toxicity of the major mycotoxins that occur in beverages, the methods available for their detection and quantification, and the strategies for their control. In addition, some novel techniques for controlling mycotoxins in the postharvest stage are highlighted.

Microbial inactivation by high pressure processing: principle, mechanism and factors responsible

High-pressure processing (HPP) is a novel technology for the production of minimally processed food products with better retention of the natural aroma, fresh-like taste, additive-free, stable, convenient to use. In this regard safety of products by microbial inactivation is likely to become an important focus for food technologists from the research and industrial field. High pressure induces conformational changes in the cell membranes, cell morphology. It perturbs biochemical reactions, as well as the genetic mechanism of the microorganisms, thus ensures the reduction in the microbial count. Keeping in view the commercial demand of HPP products, the scientific literature available on the mechanism of inactivation by high pressure and intrinsic and extrinsic factors affecting the efficiency of HPP are systematically and critically analyzed in this review to develop a clear understanding of these issues. Modeling applied to study the microbial inactivation kinetics by HPP is also discussed for the benefit of interested readers.

Inactivation Mechanism of Aspergillus flavus Conidia by High Hydrostatic Pressure

This study investigated the inactivation mechanism of Aspergillus flavus conidia by high hydrostatic pressure (HHP). Activity counts, scanning electron microscopic (SEM) analysis, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to study the effects of the HHP treatment on the morphology and protein composition of A. flavus spores. The results showed that that a 3-min-lasting 600 MPa treatment could completely abolish 10⁷ colony-forming units/mL of live fungi. Furthermore, we also observed that lower spore viability corresponded to a higher Propidium Iodide absorption rate. The SEM images revealed that HHP disrupted the spore morphology and resulted in pore formation that led to the release of intracellular molecules, such as nucleic acids and proteins. The nucleic acid and protein concentration in the spore suspension increased in parallel with the increasing treatment pressure. The SDS-PAGE analysis showed that there were differences in the protein bands between the HHP-treated and untreated A. flavus spores, as the HHP treatment caused partial protein degradation and extracellular release. Therefore, the results of this study proved that high pressure could induce a morphological disruption in the internal and external cellular structures and degrade intracellular and extracellular proteins leading to an inactive state in A. flavus.

Impact of high-pressure treatment on casein micelles, whey proteins, fat globules and enzymes activity in dairy products: a review

The quality and safety of food products are the two factors that most influence the demands made by consumers. Contractual food sterilization and preservation methods often result in unfavorable changes in functional properties of foods. High-pressure processing (HPP) (50-1000 MPa) is a non-thermal preservation technique, which can effectively reduce the activity of spoilage and pathogenic microorganisms with minimal impact on the functional and nutritional properties of food. Comprehensive inquires have disclosed the potential profits of HPP as an alternative to heat treatments by affecting the structure of milk components, particularly proteins and fats. The present paper aims to investigate the effects of HPP on milk components including fats, casein, whey proteins, enzymes, and minerals, as well as on the industrial production of milk and dairy products including cheese, yogurt, ice cream, butter, cream, and probiotic dairy products. HPP allows to extend shelf life of products without the use of additives, meeting current consumer demands. The assurance of microbial safety and the production of food products with minimal changes in quality characteristics (organoleptic, nutritional, and rheological properties) are among its main effects. In addition, the nutritional value of HPP-treated dairy products is also preserved.

Identification of Precursors and Formation Pathway for the Heterocyclic Aromatic Amine 2-Amino-3-methylimidazo(4,5-f)quinoline (IQ)

Food processing is responsible for the destruction of some health hazards, but it is responsible for the formation of new ones. Among them, the formation of heterocyclic aromatic amines (HAAs) has received a considerable attention because of their carcinogenicity. In spite of this, HAA formation is still poorly understood. This study was undertaken to identify precursors and formation pathways for 2-amino-3-methylimidazo(4,5-f)quinoline (IQ). IQ was produced by reaction of acrolein, crotonaldehyde, creatinine, and ammonia. Reaction conditions were studied, and its activation energy (E_a) was determined to be 77.0 ± 1.3 kJ/mol. IQ formation was always accompanied by the formation of the HAA 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ), which was produced with an E_a of 72.2 ± 0.4 kJ/mol. A reaction pathway for the competitive formation of IQ and MeIQ is proposed. Obtained results demonstrate the significant role of reactive carbonyls (the food carbonylome) in HAA formation and provide evidences for designing HAA mitigation strategies.