Antioxidant activity of thymol essential oil and inhibition of polyphenol oxidase enzyme: a case study on the enzymatic browning of harvested longan fruit

Abstract Background Enzymatic browning and microbial decay are the primary concerns that limit the postharvest life of longan fruit. These factors can be effectively prevented by sulfur dioxide (SO2) fumigation; however, due to the safety and regulatory issues of SO2, other alternatives must be tested. In this study, antioxidant and antimicrobial activities of thymol were determined against the pericarp browning and decay of longan fruit. A simple, cost-effective method was designed for its controlled release. Thymol vapors were obtained from the slurry prepared from 5 g of thymol in 5 mL of distilled water in a 180-mL glass jar, hermetically sealed and allowed for 24 h to accumulate the vapors in the headspace. Fruits were packed in polyethylene packages and fumigated with thymol through a septum. Non-fumigated fruits served as control and all the packages were stored at 25 ± 2 °C for 8 days. Results Thymol significantly (P ≤ 0.05) retarded pericarp browning (BI), delayed the decay incidence (DI) and maintained high color values of longan pericarp. Thymol also retained high total phenolic (TPC) and total flavonoid (TFC) contents, inhibited polyphenol oxidase (PPO) and peroxidase (POD) activities than those in control. A high coefficient of correlation of PPO with BI (r = 0.86), L* (r = − 0.94), weight loss (r = 0.93), TPC (r = − 0.77), TFC (r = − 0.80), DI (r = 0.92) and many other quality and color parameters indicated the antioxidant efficacy of thymol. Longer shelf life of 8 days with good quality attributes was obtained in thymol-treated fruits than 6 days in control. Conclusion Thymol could be effectively used as a natural antioxidant for a wide range of fruits. Graphic abstract

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Cost Effective Method for Toxicity Screening of Pharmaceutical Wastewater Containing Inorganic Salts and Harmful Organic Compounds

Environmental and Climate Technologies ◽

10.2478/rtuect-2019-0004 ◽

2019 ◽

Vol 23 (1) ◽

pp. 52-63 ◽

Cited By ~ 2

Author(s):

Elina Strade ◽

Daina Kalnina

Keyword(s):

Activated Sludge ◽

Biological Treatment ◽

Oxygen Demand ◽

Cost Effective ◽

Practical Implementation ◽

Toxicity Screening ◽

Pharmaceutical Wastewater ◽

Cost Effective Method ◽

Wide Range ◽

Wastewater Biological Treatment

Abstract Pharmaceutical wastewater biological treatment plants are stressed with multi-component wastewater and unexpected variations in wastewater flow, composition and toxicity. To avoid operational problems and reduced wastewater treatment efficiency, accurate monitoring of influent toxicity on activated sludge microorganisms is essential. This paper outlines how to predict highly toxic streams, which should be avoided, using measurements of biochemical oxygen demand (BOD), if they are made in a wide range of initial concentration. The results indicated that wastewater containing multivalent Al3+ cations showed a strong toxic effect on activated sludge biocenosis irrespectively of dilutions, while toxicity of phenol and formaldehyde containing wastewater decreased considerably with increasing dilution. Activated sludge microorganisms were not sensitive to wastewater containing halogenated sodium salts (NaCl, NaF) and showed high treatment capacity of saline wastewater. Our findings confirm that combined indicators of contamination, such as chemical oxygen demand (COD), alone do not allow evaluating potential toxic influence of wastewater. Obtained results allow identifying key inhibitory substances in pharmaceutical wastewater and evaluating potential impact of new wastewater streams or increased loading on biological treatment system. Proposed method is sensitive and cost effective and has potential for practical implementation in multiproduct pharmaceutical wastewater biological treatment plants.

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Diagnostic optical sequencing

10.1101/685792 ◽

2019 ◽

Author(s):

Lee E. Korshoj ◽

Prashant Nagpal

Keyword(s):

Single Molecule ◽

Point Of Care ◽

Cost Effective ◽

Diagnostic Methods ◽

Sequencing Platform ◽

Molecular Variants ◽

Cost Effective Method ◽

Wide Range ◽

Lactamase Gene ◽

Modified Nucleobases

AbstractAdvances in precision medicine require high-throughput, inexpensive, point-of-care diagnostic methods with multi-omics capability for detecting a wide range of biomolecules and their molecular variants. Optical techniques have offered many promising advances towards such diagnostics. However, the inability to squeeze light with several hundred-nanometer wavelengths into angstrom-scale volume for single nucleotide measurements has hindered further progress. Recently, a block optical sequencing (BOS) method has been shown for determining relative nucleobase content in DNA k-mer blocks with Raman spectroscopy, and a block optical content scoring (BOCS) algorithm was developed for robust content-based genetic biomarker database searching. Here, we performed BOS measurements on positively-charged silver nanoparticles to achieve 93.3% accuracy for predicting nucleobase content in DNA k-mer blocks (where k=10), as well as measurements on RNA and chemically-modified nucleobases for extensions to transcriptomic and epigenetic studies. Our high-accuracy BOS measurements were then used with BOCS to correctly identify a β-lactamase gene from the MEGARes antibiotic resistance database and confirm the Pseudomonas aeruginosa pathogen of origin from <12 content measurements (<15% coverage) of the gene. These results prove the integration of BOS/BOCS as a diagnostic optical sequencing platform. With the versatile range of available plasmonic substrates offering simple data acquisition, varying resolution (single-molecule to ensemble), and multiplexing, this optical sequencing platform has potential as the rapid, cost-effective method needed for broad-spectrum biomarker detection.

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Chemistry of enzymatic browning in longan fruit as a function of pericarp pH and dehydration and its prevention by essential oil, an alternative approach to SO2 fumigation

PeerJ ◽

10.7717/peerj.11539 ◽

2021 ◽

Vol 9 ◽

pp. e11539

Author(s):

Muhammad Rafiullah Khan ◽

Chongxing Huang ◽

Yasser Durrani ◽

Ali Muhammad

Keyword(s):

Essential Oil ◽

Water Loss ◽

Antimicrobial Properties ◽

Titratable Acidity ◽

Soluble Solids ◽

Enzymatic Browning ◽

Alternative Means ◽

Postharvest Life ◽

Highly Correlated ◽

Pericarp Browning

Background Longan fruit is a rich source of bioactive compounds; however, enzymatic browning of pericarp and microbial decay have limited its postharvest life. SO2 has widely been used to overcome these limitations; however, due to safety and regulatory concerns, alternative means should be identified. In this study, antioxidant and antimicrobial properties of thymol (TH) essential oil were investigated against the enzymatic browning and decay of longan fruit. Methods Fruits were coated with TH (4%) for 5 min, sealed in polyethylene (PE) packages and stored at 4 °C for 42 d. Fruits immersed in distilled water (DW) and stored in PE were used as control. Results TH extended the postharvest life of longan to 42 d than 28 d in DW. TH residues decreased from 142 to 11.17 mg kg–1, while no residues were found at day 42. TH significantly (P ≤ 0.05) reduced the respiration rate, inhibited polyphenol oxidase (PPO) and peroxidase (POD) enzyme activities, sustained high phenols/flavonoids and prevented pericarp browning (BI) than DW. TH also effectively (P ≤ 0.05) maintained the color values, firmness of peel and aril, total soluble solids (TSS), titratable acidity (TA), inhibited decay incidence (DI) and resulted in lower ethanol content than DW. BI as a function of pericarp pH was highly correlated; pH and BI (r = 0. 97), with PPO (r = 0.93) and with water loss (r = 0.99). A high coefficient of correlation of BI was found with the pericarp pH, enzymes, phenolic, water loss and decay incidence with ethanol. TH could be the best alternative to SO2 and other synthetic preservatives.

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Preliminary characterization of the enzyme polyphenol oxidase and rheological behavior from Averrhoa carambola juice

Revista Facultad Nacional de Agronomía Medellín ◽

10.15446/rfna.v70n1.61769 ◽

2017 ◽

Vol 70 (1) ◽

pp. 8099-8113 ◽

Cited By ~ 1

Author(s):

Elizabeth Murillo ◽

Juan Guillermo Aristizábal ◽

Walter Murillo ◽

Albert Ibarz Ribas ◽

Jonh Jairo Méndez ◽

...

Keyword(s):

Polyphenol Oxidase ◽

Flow Behavior ◽

Maximum Activity ◽

Soluble Solids ◽

Enzymatic Browning ◽

Aqueous Fraction ◽

Averrhoa Carambola ◽

Oxidase Enzyme ◽

Solids Content ◽

Physical And Chemical

Averrhoa carambola fruit represents a potential as an agro-industrial production line. A restriction on the use of this exotic fruit is the susceptibility to enzymatic browning, affecting nutritional and visual acceptance. The aim of this study was to determine the physical and chemical composition of A. carambola at three stages of maturity. The polyphenol oxidase enzyme has also been characterized on the fruits and juices. Also, the enzymatic effect on the ripening stages and the fruit juices flow behavior were equally determined using different rheological models. The increasing in degrees Brix (unripe (UR) 6.63 ± 0.25, intermediate (IN) 6.8 ± 0.10 and ripe (R) 8.26 ± 0.37) and the decreasing of the pectinic content (UR 4.35% ± 0.98, IN 3.6% ± 1.26 and R 2.25% ± 0.76) could be considered as indicators of fruit ripening. The protein content and levels of organic acids decreased during the ripening of fruit was observed, indicate a high metabolic rate during this process. For all stages, the polyphenol oxidase exhibited a maximum activity at pH 8 and 40 °C. In the fruit aqueous fraction, the enzyme would be an appropriate indicator in industrial handling (temperatures below 20 °C and pH less than 7), which would control enzymatic browning. According to the rheological study, the viscosity variation (η: UR (13.4 to 1.1), IN (15.4 to 1.4), R (69.6 to 2.9)) with temperature changes (10 to 50 °C) is adjusted to the Arrhenius equation, whereas the effect of soluble solids content on the samples viscosity was accurately described by an exponential equation. This appears to be the first work to study the rheological properties and polyphenol oxidase enzyme of A. carambola fruit in our country, the information provided from this study could be helpful to the successful development of new food functional products.

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A Practical Access to Functionalized Alkyl Sulfinates

Synlett ◽

10.1055/s-0036-1591588 ◽

2018 ◽

Vol 29 (12) ◽

pp. 1622-1626

Author(s):

M. Haddad ◽

P. Phansavath ◽

V. Ratovelomanana-Vidal ◽

C. Tran ◽

B. Flamme ◽

...

Keyword(s):

Functional Groups ◽

Cost Effective ◽

Good Tolerance ◽

Mild Conditions ◽

Cost Effective Method ◽

Wide Range

We describe herein a three-step synthesis of aliphatic sulfinates. This cost-effective method involves the use of 2-mercaptobenzothiazole under mild conditions and exhibits good yields (up to 78% over three steps). This approach provides an access to a wide range of functionalized sulfinates. A good tolerance with respect to diverse functional groups (alkene, alkyne, ether, acetal) was also noted.

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A SIMPLE CO2 EXTRACTION METHOD FOR RADIOCARBON ANALYSES OF DISSOLVED INORGANIC CARBON IN WATER SAMPLES WITHOUT A CARRIER GAS

Radiocarbon ◽

10.1017/rdc.2021.48 ◽

2021 ◽

pp. 1-15

Author(s):

Hiroshi A Takahashi ◽

Hiroko Handa ◽

Masayo Minami

Keyword(s):

Water Samples ◽

Extraction Method ◽

Inorganic Carbon ◽

Dissolved Inorganic Carbon ◽

Cost Effective ◽

Carrier Gas ◽

Vacuum Line ◽

Cost Effective Method ◽

Wide Range ◽

Cryogenic Trapping

ABSTRACT We developed a simple and cost-effective method for extracting carbon from dissolved inorganic carbon (DIC) in water samples without a carrier gas. This method only slightly modifies the existing vacuum line for CO2 purification in radiocarbon research laboratories by connecting several reservoirs and traps. The procedure consists of repeated cycles of CO2 extraction from water into the headspace of the reaction container, expansion of the extracted gas into the vacuum line, and cryogenic trapping of CO2. High CO2 yield (∼98%) was obtained from a variety of water samples with a wide range of DIC concentrations (0.4–100 mmol·L−1, in the case of 1.2 mgC). The δ13C fractionation depended on the CO2 yield, while the 14C concentration was constant within the error range, regardless of the CO2 yield. The average δ13C discrepancy between the results of this method and direct analyses made using the GC-IRMS was 0.02 ± 0.06‰. The standard deviations (1σ) in fraction of modern carbon (F14C) ranged from 0.0002 to 0.0004 for waters below 0.01 of F14C, and below 0.8% of F14C values for waters above 0.1. We conclude that this method is useful for effectively extracting CO2 from DIC in water and yields accurate 14C data.

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Polifenol Oksidaz Enzimi ve İnaktivasyon Yöntemleri

Turkish Journal of Agriculture - Food Science and Technology ◽

10.24925/turjaf.v6i3.333-345.1727 ◽

2018 ◽

Vol 6 (3) ◽

pp. 333

Author(s):

Leman Yılmaz ◽

Yeşim Elmacı

Keyword(s):

Phenolic Compounds ◽

Polyphenol Oxidase ◽

Fruits And Vegetables ◽

Pulse Electric Field ◽

High Pressure Processing ◽

Alternative Methods ◽

Economic Losses ◽

Enzymatic Browning ◽

Copper Proteins ◽

Oxidase Enzyme

Polyphenol oxidase enzyme is found in vegetables and fruits, as well as in some animal organs and microorganisms. Polyphenol oxidase enzyme responsible for enzymatic browning is a group of copper proteins that catalyses the oxidation of phenolic compounds to quinones, which produce brown pigments, commonly found in fruits and vegetables. During the industrial preparation of fruits and vegetables, results of catalytic effect of polyphenol oxidase causes enzymatic browning. Enzymatic browning impairs the appearance of products containing phenolic compounds along with undesirable colour, odor and taste formation and significant loss of nutritional value of the products. This affects the acceptability of the products by the consumers and causes economic losses. In this review, some characteristics of polyphenol oxidase enzyme in different fruits and vegetables have been reviewed and information about chemical antibrowning agents, thermal applications, irradiation applications and alternative methods such as high pressure processing, pulse electric field, supercritical carbon dioxide and ultrasound applications to inactivate this enzyme has been presented.

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Antioxidant and antibacterial insights into the leaves, leaf tea and medicinal roots from Astragalus membranaceus (Fisch.) Bge.

Scientific Reports ◽

10.1038/s41598-021-97109-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anim Okyere Samuel ◽

Bao-Ting Huang ◽

Yuan Chen ◽

Feng-Xia Guo ◽

Dou-Dou Yang ◽

...

Keyword(s):

Antioxidant Activity ◽

Antioxidant Activities ◽

Antimicrobial Activities ◽

Water Soluble ◽

Astragalus Membranaceus ◽

Total Amino Acid ◽

Total Phenolic ◽

Plant Leaves ◽

Bioactive Components ◽

Wide Range

AbstractUsed as traditional Chinese medicine, Astragalus membranaceus (Fisch.) Bge. (A. membranaceus) roots are also used as tonic food material in a wide range of applications, while the leaves are left in the field, unused. Therefore, comprehensively exploring and utilizing the leaves will inevitably reduce the associated resource waste and environment pollution. In this study, the plant leaves were processed into tea using green tea processing technology. Bioactive components, antioxidant and antibacterial activities of the Leaf Tea (LT) and Dry Leaves (DL) were studied, and compared to that of the Dry Roots (DR). The results showed that the polysaccharides content (POL) in the DR (20.44%) was twice as high as the DL (10.18%) and LT (8.68%). However, the DL contained 36.85% more water-soluble extracts (WSE), 35.09% more ethanol-soluble extracts (ESE), 409.63% more total flavonoid content (TFC), 221.01% more total phenolic content (TPC) and 94.34% more proteins, and the LT contained 26.21% more WSE, 40.64% more ESE, 326.93% more TFC, 191.90% more TPC and 37.71% more proteins. The total amino acid (AA) content in the DR was 8.89%, while in that of the DL and LT were 24.18% and 28.96% respectively, nearly 3-times higher than that of the DR. The antioxidant activity of DR was much lower than those of DL and LT, both of which had antioxidant activity closer to that of Vitamin C (VC) and the antioxidant activities were even stronger when the optimal concentration was reached. Except for Aspergillus niger and Staphylococcus aureus, the DL and DR exhibited inhibition activities to Salmonella, Bacillus subtilis, Escherichia coli and yeast, while the LT had antimicrobial activities against all the strains except for A. niger. In summary, compared with the most commonly used DR, the DL and LT from A. membranaceus contained higher bioactive components, and stronger antioxidant and antimicrobial activities. Producing leaf tea may be an appropriate way to economically and reasonably utilize the plant leaves which are by-products.

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Newborn Haemoglobinopathy Carrier Screening: Towards Comprehensive and Improved Patient Care of Sickle Cell Disease in Oman, a Cost Effective Analysis.

Blood ◽

10.1182/blood.v110.11.5155.5155 ◽

2007 ◽

Vol 110 (11) ◽

pp. 5155-5155

Author(s):

Salam Alkindi ◽

Anil Pathare ◽

Ali Al Madhani ◽

Shoaib Al Zadjali ◽

S. Muralitharan ◽

...

Keyword(s):

Cord Blood ◽

Clinical Care ◽

Cost Effective ◽

Mononuclear Leukocytes ◽

Sultanate Of Oman ◽

Blood Samples ◽

Beta Thalassaemia ◽

Cost Effective Method ◽

Wide Range ◽

Blood Screening

Abstract Objective: The aim of the study was to establish neonatal cord blood screening in the Sultanate of Oman, in an effort to determine the prevalence of haemoglobinopathies by a cost-effective method. Background: Oman is a country with a two million population comprising of a wide range of ethnic groups, high rates of consanguinity and increased incidences of inter-cousin marriages all leading to an increased prevalence of haemoglobinopathies. High performance liquid chromatography [HPLC] is a powerful tool to screen newborns for haemoglobinopathies. Neonatal screening includes cord blood samples collection, screening and follow up of all newborns with abnormal results. Methods: A total of 7837 consecutive cord blood samples were screened for the presence of possible haemoglobinopathies by HPLC using Biorad Variant II program between April 2005 & March 2007. Complete blood counts [CBC] were also obtained on Cell Dyn 4000 automated blood cell counter. All samples were then processed to isolate and store mononuclear leukocytes for subsequent molecular diagnostics. Results: The findings indicated a 47.07% incidence of α-thalassaemia, based on low mean cell volume [MCV] & mean cell haemoglobin [MCH] on the CBC and significant amounts of Hb Barts on HPLC. Furthermore, the overall incidence of other haemoglobinopathies was 9.87%, with 5.47% incidence of sickle haemoglobin. On HPLC, D-window, E-window and C-window were present in 0.93%, 0.77% and 0.06% of the samples respectively. Figure Figure Since HPLC cannot diagnose beta thalassemia major at birth, in samples with HbA below 10%, the beta globin gene was directly sequenced including the promoter, all exons and introns in these samples. Amongst 206(2.62%) samples sequenced, beta thalassaemia trait was confirmed in 201 cases and 5 cases were homozygous for beta thalassaemia. Additionally, direct sequencing of all abnormal samples with HbS,[n=429] HbD,[n=73], HbE[n=42] and HbC[n=5] was also performed on ABI 3100 Genetic Analyzer to assign the genotype status to these subjects and to validate the HPLC results. Amongst the 429 samples with HbS sequenced, 24 samples were homozygous (0.3%) and were referred for comprehensive clinical care programme. Conclusions: The significantly high incidence of haemoglobinopathies in newborns in the Sultanate of Oman emphasizes the value of neonatal cord blood screening to be implemented as the first step in the national strategy towards total management of haemoglobinopathies including early diagnosis, comprehensive clinical care and counseling of the affected families. The results of this large study indicate that using HPLC [<2 USD/sample] and prescreening of parents to select only abnormal samples for neonatal cord blood screening [<10% samples] can be recommended as a highly cost-effective method targeted to screen only the abnormal samples.

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