TEM results indicated that bacterial cell walls increased when grown in media supplemented with acrylamide. Participated in planning the work, had main responsibility for data collection and processing, evaluation of results and manuscript writing.
Introduction
- Overview
- Statement of the Problem
- Research Objectives
- Relevant Literature
- Formation of Acrylamide
- Occurrence, Dietary Exposure, and Toxicity
When the food is fried and the oil is heated above its smoke point, the acrolein pathway is initiated (Liu et al., 2015). Exposure to acrylamide has been quantified in relation to different eating habits, age groups, populations and regions (Maan et al., 2022).
Literature Review: An Overview of Microbial Mitigation
Introduction
For example, in wastewater treatment plants, it is used to produce polyacrylamide as a flocculant. However, limited reviews have provided general information regarding the use of microorganisms and cell-free extracts to reduce acrylamide content (Duda-Chodak et al., 2016).
Acrylamide Formation
It has been reported that the addition of gluten to bread as a protein source caused the formation of acrylamide (Claus et al., 2006). The next section will discuss the dangers of acrylamide to human health and the importance of studying methods for its removal.
Dietary Intake, Occurrence, and Toxicity
Mesías and Morales (2016) studied the dietary intake of acrylamide in coffee from vending machines in Spain and estimated the intake level to be 0.037 μg/kg bw/day (range well below the level of 0.2 μg/kg bw/day , defined by WHO and the Food and Agriculture Organization of the United Nations as the lowest level of no observed adverse effects for a non-carcinogenic endpoint (World Health Organization (WHO), 2017) In the meantime, 2.6 μg/kg body weight/day has been proposed as the maximum tolerable daily intake of acrylamide to prevent the risk of developing cancer.
Regulatory Guidelines of Acrylamide in Foods
Microbial Mitigation
- Acrylamide Mitigation by LAB
- Acrylamide Mitigation by Yeast
- Acrylamide Mitigation by Cell-free Extracts
In a culture fluid environment, the reduction of acrylamide has been associated with its binding affinity to bacterial cell walls (Serrano-Niño et al., 2014). Up to 73% of the acrylamide content was reduced by these bacteria (Rivas-Jimenez et al., 2016).
Mechanisms of Microbial Mitigation
2014) agreed with this comment, saying that “cell surface properties, which determine bio-interface phenomena such as adhesion and cell aggregation, depend on the structure of the cell wall. In addition, proteins associated non-covalently with the cell wall play a protective role for the microorganism, and the bonds can be dissociated by agents that alter the hydrogen bonds.
Non-microbial Mitigation of Acrylamide
A comparison between non-microbial (Table 5) and microbial (Table 5) mitigation approaches revealed the superiority of microbial mitigation approaches. In addition, microbial approaches can improve the nutritional quality and preserve the organoleptic properties of foods. High voltage electric discharge (HVED) treatment can disrupt the bacterial cell wall, which reduces acrylamide formation with water as solvent.
Conclusions
Their ability to reduce acrylamide, their overall health effect and their ability to remove other types of contaminants (eg mycotoxins) make LAB a potentially affordable and. Author Contributions: AS Albedwawi: drafted the manuscript and prepared tables; AN Olaimat, TM Osaili, AA Al-Nabulsi: contributed to the non-microbial approaches and the revision of the manuscript; MS Turner, SQ Liu, Nagendra P.
Acrylamide Elimination by Lactic Acid Bacteria: Screening,
Introduction
Manipulation of the food processing conditions (temperature, pH, incubation time, vacuuming) to reduce acrylamide formation has also been reported (Zhang et al., 2020). A microbial approach has been presented to reduce the presence of acrylamide (Albedwawi et al., 2021; N. Khorshidian et al., 2020). The mechanism for the removal of acrylamide by microorganisms is not fully investigated and understood (Albedwawi et al., 2021).
The study of acrylamide removal with new microorganisms (such as lactic acid bacteria (LAB) and yeast) is still in great demand as suggested by various studies (Albedwawi et al., 2021; Nematollahi et al., 2021).
Materials and Methods
- Strains of Bacteria
- Preparation of Stock and Working Solutions of Acrylamide
- Acrylamide Binding Assay – Preliminary Screening for Media
- Optimization of Acrylamide Removal Using Box-Behnken Design
- In vitro Digestion by INFOGEST2.0 Model
- Quantification of Acrylamide by LC-MS-MS
- Understanding Mchanism of Acrylamide Binding by LAB
- Statistical Analysis
Then, the treated samples were cut into 50-60 nm thick sections with an ultramicrotome (UC6, LEICA, Germany). The zeta potential of LAB cells was measured to test the stability of a colloid containing MRS slurry, LAB and acrylamide. Bacterial cell samples were lyophilized and directly placed on a Diamond/ZnSe crystal plate (Perkin-Elmer).
To determine both means and standard deviations of results from screening acrylamide by LAB, Minitab v.21 (Minitab Ltd, Coventry, UK) was used.
Results
- Screening of Acrylamide Removal by LAB
- Optimization of Acrylamide Removal
- Acrylamide Removal Under In vitro Digestion
- Mechanisms of Acrylamide Removal
By analyzing Figure 6 and studying the interaction of the factors with each other and their impact on S. The effect of the matrix on acrylamide removal during in vitro digestion was also investigated. Note that pH is an important factor affecting zeta potential, it can be suggested that acrylamide changed the pH of the samples.
The control showed no atomic percentages of O, Na, Mg, Al or K, which could explain that acrylamide caused some changes in the chemical composition of the bacteria.
Discussion
For example, Lactobacillus johnsonji CECT 289 had the highest reduction of 97.4% removal of ochratoxin A in MRS among all LAB strains tested under gastrointestinal digestion (Luz et al., 2018b). The removal is influenced by several factors, such as the density of bacterial cells, the concentration of the toxin, the viability of the bacteria and the incubation temperature. These results indicate that the adsorption capacity depends on the number of strains and bacteria, which is in agreement with the results obtained herein (Ge et al., 2017; Shen et al., 2019a).
SEM-EDS results showed significant changes in the wavenumbers of the C-O, C=O and N-H, the functional groups in the LAB cell wall that affect acrylamide adsorption, as reported by Wang et al., (2015).
Conclusions
To understand the mechanism of acrylamide removal, lactic acid bacterial cells were characterized via scanning electron microscopy in combination with energy dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). Cell charges were characterized by zeta potential and functional groups by Fourier transfer infrared spectroscopy (FTIR). The results from both strains indicate that LAB can be used to eliminate acrylamide in the GI tract, but further in vivo studies in the human GI tract are needed.
Acknowledgments: The authors are very grateful to Dubai Central Laboratory and Khalifa University for their support.
Investigating Acrylamide Mitigation by Potential Probiotics
Introduction
The MR is a non-enzymatic browning reaction when food is exposed to a high temperature above 120°C (baking, frying and grilling) (Pedreschi et al., 2014). Industrially, LAB are used as culture starters in food production to produce aroma, flavor, texture and color (Bangar et al., 2021). Regular adequate doses can have a beneficial health impact to mitigate potentially toxic elements such as lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) (Alizadeh et al., 2021).
Nevertheless, in-depth information on the mechanism of acrylamide mitigation by microorganisms is highly regarded (Albedwawi et al., 2021).
Materials and Methods
- Bacteria Propagation
- Preparation of Stock and Working Solutions of Acrylamide
- Screening for Acrylamide Mitigation
- Box-Behnken Design (BBD)
- In vitro Gastrointestinal Digestion (INFOGEST2.0)
- Quantification of Acrylamide by LC-MS-MS
- Understanding Mechanism of Acrylamide Removal
- Statistical Analysis
The zeta potential of selected isolates was measured with a Zetasizer Nano ZS-90 (Malvern Instruments Ltd, Worcestershire, UK). The morphology and basic composition of the bacterial cell pellets were examined using SEM-EDS. The radius, height, and elemental composition of the cell pellets were assessed by Quanta 250 ESEM according to the detailed method described previously (Ge et al., 2017; Shen et al., 2019a).
The Tecnai G2 transmission electron microscope (TEM) was used to determine the thickness of the cell pellets.
Results
- Screening and Optimization of Acrylamide Removal
- In vitro Gastrointestinal Treatments
- Mechanisms of Acrylamide Removal
The analysis of variance in Table 9 shows that there are two significant factors for B. . breve: 1) incubation temperature (P < 0.008) interaction between time and 2) salt (P. The remaining detailed analysis of the EDS spectra is presented in Figure 14B in the supplementary information. N was higher in the control and O was equal to zero, while the Cmax was higher in both bacterial strains compared to the control, which could explain that AA caused some variation in the chemical composition of the bacterial cell wall.
Based on the optical observation, the TEM images revealed an increase in the thickness of the cell wall of both Lb.
Discussion
71 affected by bacterial cell density, toxin concentration, bacterial viability and incubation temperature (Zhao et al., 2015). Factors such as pH, initial viability, incubation temperature and time can be adjusted to increase the removal percentage (Bangar et al., 2021; Yousefi et al., 2021). Bifidobacteria, Propionibacteria and Enterobacteria were strain and metal dependent when assessed for their ability to remove Pb, Cd and Al (George et al., 2021).
FTIT results showed significant changes in C-O, C=O, and N-H wavenumbers, which are the functional groups in LAB and bifidobacterial cell walls that affect AA adsorption (Wang et al., 2015).
Conclusion
Acrylamide Adsorption by Enterococcus durans and
Introduction
In 2002, the Swedish Food Authority and Stockholm University announced that acrylamide could be formed in foods heated above 120°C (Perera et al., 2021). High amounts of acrylamide were found in products such as potato chips, bread and coffee (Shao et al., 2021). However, these approaches may have an undesirable effect on the sensory properties of the final food products (Shen et al., 2019a).
LAB can prevent microbial spoilage, which can then extend the shelf life of food (Bangar et al., 2021).
Materials and Methods
- Bacterial strains
- Preparation of Stock and Working Solutions of Acrylamide
- Acrylamide Binding Assay – Preliminary Screening for Media
- Optimization of Acrylamide Removal Using BBD
- In-vitro Digestion by INFOGEST2.0 Model
- Quantification of Acrylamide by LC-MS-MS
- Understanding the Mechanism of Acrylamide Binding by LAB
- Statistical Analysis
The samples were continuously shaken at 120 rpm throughout the in vitro digestion process (2 minutes in the oral phase, 2 hours in the gastric phase and 2 hours in the intestinal phase). For acrylamide analysis, the samples were frozen at -20°C for later analysis, as described in Section 2.6. Lyophilized bacterial cell samples were placed directly on a Diamond/ZnSe crystal plate (Perkin-Elmer).
The prepared samples were cut into 50–60 nm thick sections using an Ultramicrotome (UC6, LEICA, Wetzlar, Germany) (Shen et al., 2019a).
Results
- Screening of Acrylamide Removal by LAB
- Optimization of Acrylamide Removal
- Acrylamide Removal Under In-vitro Digestion
- Mechanisms of Acrylamide Removal
The removal of acrylamide by microorganisms has been reported to be species and strain dependent (Albedwawi et al., 2021). By analyzing Figure 17A-L and observing the interaction between the factors and the removal of acrylamide by both LAB strains, we note that E. Our results showed that the media matrix (the in vitro digestion solutions) had a small effect (< 1.1%) on the removal of acrylamide.
The peptidoglycan layer of the cell wall for various stains contains CO, OH and NH functional groups as major components.
Discussion
The present study supported the results of previous studies which determined that the C=O, C-O & N-H groups were the primary functional groups involved in the adsorption of acrylamide by LAB according to FITR and SEM-EDS (Albedwawi et al., 2022; These groups are the key components in. 2019) also reported that increased cell wall roughness can improve the adsorption capacity of the strain for acrylamide (Shao et al., 2021;. It was also reported that Lactobacillus kefiranofacein was used to adsorb mycotoxin patulin in apple juice (Bahati et al., 2021).
The bacterial cell wall was the main contributor binding the toxin and the thicker it was, the higher the adsorption results.
Conclusions
2020) supported the previous results and stated that acrylamide had an impact on the viability of L. The functional C=O, C-O and N-H are the main causes of the adsorption, together with the distorted shape of the cell wall. This study indicates that LAB can be used in the future to remove toxins in food and human intestines because LAB can tolerate different conditions.
Further research is needed in vivo to test LAB's ability to bind acrylamide and other toxins in the human digestive system.
General Discussion
101 studies supported the dissertation's conclusion that optimizing conditions increased LAB binding results.
Conclusion, Future Perspectives and Limitations
Study on the reduction of acrylamide in mixed rye bread by fermentation with bacteriocin-like inhibitory substances producing lactic acid bacteria in combination with Aspergillus niger glucoamylase. Reduction of acrylamide formation in French fries during deep frying in sunflower oil using pomegranate peel nanoparticle extract. Lactic acid fermented bacteria solution and brine solution on the reduction of acrylamide formed during the production of French fries.
Variation and storage conditions affect the precursor content and amount of acrylamide in potato chips.
