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Zeng M, Wu H, Han Z, Du Z, Yu X, Luo W. Metabolic Engineering of Escherichia coli for Production of 2,5-Dimethylpyrazine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:4267-4276. [PMID: 38369722 DOI: 10.1021/acs.jafc.3c08481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
2,5-Dimethylpyrazine (2,5-DMP) is a high-value-added alkylpyrazine compound with important applications in both the food and pharmaceutical fields. In response to the increasing consumer preference for natural products over chemically synthesized ones, efforts have been made to develop efficient microbial cell factories for the production of 2,5-DMP. However, the previously reported recombinant strains have exhibited low yields and relied on expensive antibiotics and inducers. In this study, we employed metabolic engineering strategies to develop an Escherichia coli strain capable of producing 2,5-DMP at high levels without the need for inducers or antibiotics. Initially, the biosynthesis pathway of 2,5-DMP was constructed that realized 2,5-DMP production from glucose. Subsequently, efforts focused on enhancing 2,5-DMP production by improving the availability of the cofactor NAD+ and precursor l-threonine. Additionally, the supply and conversion of l-threonine were balanced by optimizing the copy number of the key gene tdh on the chromosome and by modifying the l-threonine transport system. The final engineering strain D19 produced 3.1 g/L of 2,5-DMP, which is the highest titer for fermentative production of 2,5-DMP using glucose as the carbon source up to date. The strategies used in this study lay a good foundation for the production of 2,5-DMP on a large scale.
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Affiliation(s)
- Mingxi Zeng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Hui Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200231, China
| | - Zhenlin Han
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Zhiyan Du
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Xiaobin Yu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wei Luo
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
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Wang Y, Zhang H, Cui J, Gao S, Bai S, You L, Ji C, Wang S. Dynamic changes in the water and volatile compounds of chicken breast during the frying process. Food Res Int 2024; 175:113715. [PMID: 38129035 DOI: 10.1016/j.foodres.2023.113715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/10/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023]
Abstract
The influence of frying times (0, 2, 4, 6, 8, and 10 min) on the continuous changes in the water distribution and the concentrations of key volatile compounds in chicken breast during the frying process were studied. The fried chicken samples could be distinguished by PCA of E-nose and PLS-DA of GC-MS. A total of 40 volatile compounds were identified by GC-MS, and 28 compounds were verified to be the key compounds after further screening by OAVs. The T22 was increased first and then decreased, while the M22 and M23 in fried chicken were considerably decreased and increased with increasing frying time, respectively. The content of the water and the total peak area of LF-NMR in fried chicken samples during the frying process significantly decreased, and the water was transferred from high to low degrees of freedom. In addition, water content, T21, T22, M22 and L* value were positively correlated with most alcohols and aldehydes, and were negatively correlated with pyrazines, while a*, b*, M23 and all amino acids were positively correlated with pyrazines and were negatively correlated with most alcohols and aldehydes. The results may guide the production processes of fried chicken and help produce high-quality chicken products.
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Affiliation(s)
- Yongrui Wang
- College of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Heyu Zhang
- College of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Jiarui Cui
- College of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Shuang Gao
- College of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Shuang Bai
- College of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Liqin You
- College of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China
| | - Chen Ji
- College of Agricultural Sciences, Xichang University, XiChang 615000, China
| | - Songlei Wang
- College of Food Science and Engineering, Ningxia University, Yinchuan 750021, China.
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Laemont J, Barringer S. Effect of pH, Reducing Sugars, and Protein on Roasted Sunflower Seed Aroma Volatiles. Foods 2023; 12:4155. [PMID: 38002212 PMCID: PMC10670587 DOI: 10.3390/foods12224155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Sunflower seeds are a popular snack in many countries, such as the United States, China, and Spain. Sunflower seeds are typically roasted to create desirable aromas before being eaten. The desirable aromas are created by the Maillard and lipid oxidation reactions. Increasing the volatiles created by these reactions can create a more desirable product, increasing consumer acceptance of sunflower seeds. Seeds were soaked in solutions at pH 4, 7, and 9 and with added glucose, fructose, whey protein isolate, or whey protein concentrate before roasting. The resulting seeds were evaluated by selected-ion flow tube mass spectrometry to determine the volatile concentrations and by an untrained panel of consumers to determine acceptability. Increasing the pH increased the pyrazines but did not affect other volatiles. Adding reducing sugars or whey protein increased most volatiles. The fructose increased dimethylpyrazines, 2-methylpyrazine, and trimethylpyrazine concentrations more than glucose. However, the glucose increased furfural concentration more than fructose. The whey protein concentrate increased volatile levels more than any other treatment. The total Maillard volatiles and Browning index were increased by the same treatments. Sensory indicated that fructose increased desirable aroma the most, followed by whey protein treatments, and both were liked more than the pH 7 control. Optimizing roasting conditions by increasing the pH and reducing sugar and protein content can favor the Maillard reaction conditions, increasing the positive aromas associated with roasted sunflower seeds.
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Affiliation(s)
| | - Sheryl Barringer
- Department of Food Science and Technology, The Ohio State University, 110 Parker Food Science and Technology Building, 2015 Fyffe Road, Columbus, OH 43210, USA;
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Mazzucotelli M, Khomenko I, Betta E, Cetto I, Farneti B, Gabetti E, Cavallero A, Aprea E, Biasioli F. Monitoring alkyl pyrazines in roasted hazelnuts by SHS-GC-IMS: IMS response assessment and standardization. Talanta 2023; 259:124568. [PMID: 37088040 DOI: 10.1016/j.talanta.2023.124568] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/14/2023] [Accepted: 04/16/2023] [Indexed: 04/25/2023]
Abstract
Gas chromatography coupled with ion mobility spectrometry (IMS) is an analytical tool which is rapidly becoming widespread in the analysis of food volatiles. Despite this increasing popularity, an assessment of the IMS response for several flavor compound classes is not yet available. This study focuses on alkyl pyrazines and their determination in roasted hazelnut pastes. These Maillard reaction products are crucial to determine the aromatic profile of roasted foods and are suitable markers for industrial roasting monitoring. The instrumental response of 8 alkyl pyrazines was studied using a model matrix and a matrix matching approach. The results showed a relevant effect of the pyrazine ring substitution pattern on the concentration-response curve trends, highlighting that an external standardization of the IMS response is required to make possible relative abundance comparisons between analytes. A response standardization was therefore developed and applied to determine alkyl pyrazines in samples with different roasting intensity and geographical and botanical origin.
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Affiliation(s)
- Maria Mazzucotelli
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy; Center for Agriculture Food Environment C3A, University of Trento, San Michele All'Adige, Trento, Italy
| | - Iuliia Khomenko
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy.
| | - Emanuela Betta
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy
| | - Irene Cetto
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy
| | - Brian Farneti
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy
| | | | | | - Eugenio Aprea
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy; Center for Agriculture Food Environment C3A, University of Trento, San Michele All'Adige, Trento, Italy
| | - Franco Biasioli
- Research and Innovation Center, Fondazione Edmund Mach, San Michele All'Adige, Trento, Italy
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Liang D, Dirndorfer S, Somoza V, Krautwurst D, Lang R, Hofmann T. Metabolites of Key Flavor Compound 2,3,5-Trimethylpyrazine in Human Urine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:15134-15142. [PMID: 36399543 PMCID: PMC9733599 DOI: 10.1021/acs.jafc.2c06418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/26/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Pyrazines are among the most important compound class conveying the odor impressions "roasty", "nutty", and "earthy". They are formed by the Maillard reaction and occur ubiquitously in heated foods. The excretion of metabolites of the key flavor odorant 2,3,5-trimethylpyrazine, abundant in the volatile fraction of roasted coffee, was investigated. Based on literature suggestions, putative phase 1 and phase 2 metabolites were synthesized, characterized by nuclear magnetic resonance and mass spectroscopy data and used as standards for targeted, quantitative analysis of coffee drinkers' urine using stable-isotope-dilution-ultrahigh-performance liquid chromatography tandem mass spectroscopy (SIDA-UHPLC-MS/MS). The analysis of spot urine samples from a coffee intervention study revealed 3,6-dimethylpyrazine-2-carboxylic acid, 3,5-dimethylpyrazine-2-carboxylic acid, and 5,6-dimethylpyrazine-2-carboxylic acid were quantitatively dominating metabolites. Only negligible traces of pyrazinemethanols (3,6-dimethyl-2-pyrazinemethanol and 3,5,6-trimethylpyrazine-2-ol), glucuronides ((3,6-dimethylpyrazine-2-yl-)methyl-O-β-D-glucuronide and (3,5-dimethylpyrazine-2-yl-)methyl-O-β-D-glucuronide), and sulfates ((3,6-dimethylpyrazine-2-yl-)methyl-sulfate and (3,5-dimethylpyrazine-2-yl-)methyl-sulfate) were detected.
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Affiliation(s)
- Dong Liang
- Leibniz
Institute for Food Systems Biology at the Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
- Chair
for Food Chemistry and Molecular Sensory Science, Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Sebastian Dirndorfer
- Leibniz
Institute for Food Systems Biology at the Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Veronika Somoza
- Leibniz
Institute for Food Systems Biology at the Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Dietmar Krautwurst
- Leibniz
Institute for Food Systems Biology at the Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Roman Lang
- Leibniz
Institute for Food Systems Biology at the Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Thomas Hofmann
- Leibniz
Institute for Food Systems Biology at the Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
- Chair
for Food Chemistry and Molecular Sensory Science, Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
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El‐Shamy S, Farag MA. Volatiles profiling in heated cheese as analyzed using headspace solid‐phase microextraction coupled to gas chromatography coupled to mass spectrometry. EFOOD 2022. [DOI: 10.1002/efd2.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Sherine El‐Shamy
- Department of Pharmacognosy, Faculty of Pharmacy Modern University for Technology & Information Cairo Egypt
| | - Mohamed A. Farag
- Department of Pharmacognosy, Faculty of Pharmacy Cairo University Cairo Egypt
- Department of Chemistry, School of Sciences & Engineering The American University in Cairo New Cairo Egypt
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