In vitro antioxidant and antimicrobial activities of clove extract and its effectiveness in bio-composite film on storage stability of goat meat balls

The aim of this study was to find out clove extract's antimicrobial and antioxidant properties, as well as its efficacy as a bioactive ingredient in the development of bio-composite films to increase the storage stability of goat meat balls stored at 4 ± 1°C. The clove extracts (CLEs) were prepared in ethanol, hydroethanol (1:1), and water and evaluated for antioxidant and antimicrobial potential. In vitro assays of CLEs revealed more susceptibility for gram-positive bacteria than gram-negative bacteria. Among the different extracts, the clove ethanol extract (CLEE) had the highest antimicrobial activity against tested microorganisms as well as total phenolics (1.14 mg GAE/g), flavonoids (8.50 µg catechin/g), and DPPH assay (39.59%). Further, the concentration-dependent effect of CLEE (p < 0.05) on thickness and color values and antimicrobial properties of the bio-composite film were observed. The storage qualities of the product T₁ (with film; 450 µl CLEE) such as pH (6.45 ± 0.01), TBARS (0.87 ± 0.06 mg malonaldehyde/kg) value, free fatty acid (0.193 ± 0.001% oleic acid), total mesophilic count (4.98 ± 0.05 log₁₀ CFU/g), and sensory attributes (overall acceptability score: 5.67 on 8-point scale) were better (p < 0.05) than T₀ (without film; control) on day 20 of storage. Thus, the ethanolic clove extract has a superior antioxidant and antimicrobial potential. Its inclusion in the bio-composite film prolonged the storage stability of goat meat balls by controlling lipid oxidation and microbial growth. Practical Application Today's consumers are more attracted towards meat products added with natural ingredients having preservative effects. Clove extract is a classic example of a natural preservative and has excellent antimicrobial and antioxidant potential. The present study revealed that by wrapping the ethanolic clove extract-based bio-composite film on goat meat balls extended the storage stability of the product due to controlled lipid oxidation and microbial growth. Thus, such bio-composite films can be successfully applied on goat meat balls that function as a antimicrobial packaging for providing optimum organoleptic quality and better shelf life.

Assessment of the Stability of Fresh Beef Patties with the Addition of Clove Extract during Frozen Storage

The study assessed the stability for fresh beef patties with the inclusion of clove extract (CE) as a natural antioxidant in comparison to butylated hydroxytoluene (BHT) and ascorbic acid (AA) at frozen storage. Four different patties were made dependent on the added antioxidants: control (added no antioxidants), added with 0.02% BHT, 0.05% AA, and 0.1% CE. Inclusion of BHT, AA, and CE resulted in a significant reduction of thiobarbituric acid reactive substances (TBARS) and hue angle (h°) value and increase of redness (CIE a*) and chroma (C*) values (p<0.05). BHT, AA, and CE were observed effectively to retard lipid oxidation and increase color stability. BHT and AA revealed significantly (p<0.05) higher thiol content than the control and CE. However, the reduction percentage for thiol content in CE treated patties was lower than the control and AA-treated patties from first to last time of storage. Moreover, inclusion of AA and CE led to significantly (p<0.05) increased heme iron content when compared to BHT and the control. In conclusion, CE can replace the application of AA and BHT while improving lipid stability, heme iron content, and color stableness of fresh beef patties throughout frozen storage.

Biogenic Silver Nanoparticles for Trace Colorimetric Sensing of Enzyme Disrupter Fungicide Vinclozolin

We report a novel, simple, efficient, and green protocol for biogenic synthesis of silver nanoparticles (AgNPs) in aqueous solution using clove (Syzygium aromaticum) extract as a reducing and protecting agent. Ultraviolet-visible (UV-Vis) spectroscopy was employed to monitor the localized surface plasmon resonance (LSPR) band of clove extract-derived AgNPs prepared under various conditions. Fourier-transform infrared (FTIR) spectroscopy analysis provided information about the surface interaction of the clove extract with the AgNPs. Ultrahigh-resolution transmission electron microscopy (UHRTEM) results confirmed the formation of spherical, uniformly distributed clove extract-capped AgNPs with sizes in the range of 2–20 nm (average size: 14.4 ± 2 nm). Powder X-ray diffractometry analysis (PXRD) illustrated the formation of pure crystalline AgNPs. These AgNPs were tested as a colorimetric sensor to detect trace amounts of vinclozolin (VIN) by UV-Vis spectroscopy for the first time. The AgNP-based sensor demonstrated very sensitive and selective colorimetric detection of VIN, in the range of 2–16 µM (R² = 0.997). The developed sensor was green, simple, sensitive, selective, economical, and novel, and could detect trace amounts of VIN with limit of detection (LOD) = 21 nM. Importantly, the sensor was successfully employed for the determination of VIN in real water samples collected from various areas in Turkey.

Synthesis of biosurfactant‐coated magnesium oxide nanoparticles for methylene blue removal and selective Pb2+ sensing

Dyes and lead (Pb2+) are toxic compounds that can contaminant water. In this study, magnesium oxide (MgO) nanoparticles (NPs) prepared using clove, i.e. Syzygium aromaticum extract [clove extract (CE)] were used for methylene blue (MB) removal and Pb2+ ion sensing in aqueous solution. Maximum 90% MB removal was achieved using MgO NPs. The MB adsorption on MgO NPs surface followed second‐order kinetics and Langmuir isotherm. MB dye was adsorbed as a monolayer on the surface of MgO NPs with maximum adsorption capacity, 5555 mg g−1. MgO NPs were also able to selectively detect lead (Pb2+) in 1 nM–200 µM range with 24 µM (3σ) limit of detection. So, CE prepared MgO NPs are useful for MB dye adsorption and metal ion sensing applications.

Extract of Syzygium aromaticum suppress eEF1A protein expression and fungal growth

AIMS

Clove extract has therapeutic potential as an antifungal drug, yet the mechanism of action remains ambiguous. Current study aimed to address the molecular process of the antifungal activity exerted by clove extract.

METHODS AND RESULTS

The antifungal assay results showed that clove extract had some effects on all of the tested yeast. Propidium iodide staining assay showed cell membrane damage in Saccharomyces cerevisiae after treatment of clove extract for 30 h. Interestingly, SDS-polyacrylamide gel electrophoresis assays revealed that the protein expression of eukaryotic elongation factor 1 alpha (eEF1A) was suppressed significantly after treatment with clove extract (not pure eugenol). Transcriptional analyses revealed that the TEF1 and TEF2 genes (translation elongation factor EF-1 alpha) encoding eEF1A were not disturbed with the addition of clove extract; however, the expression of related genes EFB1 (translation elongation factor 1 subunit beta), ENO2 (phosphopyruvate hydratase ENO2), GSP1 (Ran GTPase GSP1), RPP0 (ribosomal protein P0), YEF3 (translation elongation factor EF-3), TEF4 (translation elongation factor EF1B gamma), and RPS2 (ribosomal 40S subunit protein S2) increased significantly.

CONCLUSIONS

These results suggest that clove extract plays a role in disrupting growth and affecting yeast metabolism. eEF1A was affected by clove extract at the protein level but not at the transcriptional level.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is based on a detailed study of antifungal action exerted by clove extract, and proposed that down-regulation of eEF1A protein expression may contribute to its antifungal activity. These results may have clinical significance for future application of clove extract as a natural antifungal agent.

Compositional Factors that Influence Lipid Peroxidation in Beef Juice and Standard Sausages

In order to identify how different additives influenced lipid peroxidation formation, a sausage only using beef juice as pigment source and a standard beef-pork meat sausage were studied. The effects of different additives, including fish oil, myoglobin, nitrite, clove extract, and calcium sources on oxidation and sensory properties were examined. Both sausage systems were stored in 3 different manners prior to testing: (1) frozen immediately at -80 °C; (2) chilled stored for 2.5 weeks followed by fluorescent light illumination at 4 °C for another 2 wk; (3) frozen at -20 °C for 5 mo. The frozen group 3 showed the highest peroxide formation and thiobarbituric acid reactive substances (TBARS) for both sausage systems. Unpolar peroxides dominated in both systems. The clove extract could offset the peroxide formation from myoglobin/beef juice and/or fish oil, but the addition of clove flavor was recognized by the sensory panelists. Calcium addition reduced lipid peroxide formation. Added nitrite and fish oil seemed to interact to stimulate nitroso-myoglobin formation. Nitrite was identified to interact with clove addition and thereby, relatively speaking, increased TBARS. The 2 sausage systems generally ranked the additives similarly as pro- and antioxidants.