Bioactive Compound, Antioxidant, and Radical Scavenging Activity of Some Plant Aqueous Extracts for Enhancing Shelf Life of Cold-Stored Rabbit Meat.

The potential radical scavenging, antioxidant activities (DPPH and ABTS) and bioactive constituents of several plant aqueous extracts (Curcuma longa, CL; Myristica fragrans, MF; Zingiber officinale, ZO; Cymbopogon citratus, CC and Thymus vulgaris, TV as well as their mixture) were investigated. The effect of these extracts on quality aspects (sensory characteristic, color traits, and Thiobarbituric acid) of rabbit meat during a 16-day cold (4 ± 2 °C) storage were investigated. Total phenolics and flavonoid contents of all extracts ranged from 13.27 ± 0.57 to 25.23 ± 0.49 mg GAE/g and 6.57 ± 0.22 to 13.24 ± 0.19 mg quercetin/g, respectively. The aqueous extract of MF had the highest (p ≤ 0.05) ABTS scavenging activity (4.55 µ mol Te/g dry extract), whereas the highest (p < 0.05) DPPH scavenging activity was detected in ZO extract (9.32 µ mol Te/g dry extract). Identification of extracts' bioactive compounds by GC-MS revealed that Eugenol (34.51%), Cinnamaldehyde (44.71%), Carvacrol (40.49%), Eicosane aldehyde (31.73%), and thymol (50.04%) are the first abundant bioactive compounds of CL, MF, ZO, CC, and TV aqueous extracts, respectively. Generally, the thiobarbituric acid reactive substances (TBARS) of all cold stored rabbit meat increased (p < 0.05) by increasing the storage time. The lowest TBARS values were detected for the samples treated with 0.2% of plant extracts mixture, which increased the shelf life of cold-stored rabbits by 50%. Significant (p < 0.05) increases in both L* and b* were observed with extended storage time. Meanwhile, the redness of the cold stored rabbit meat had an opposite trend. Treating the cold stored rabbit meat with 0.2% of the extract's mixture doubled the storage time with acceptable odor and taste. The results indicated that the studied plant extracts may be effective against rancidity and may be used as a natural antioxidant to prolong the shelf life of cold-stored rabbit meat.

Optimization of Platinum Nanoparticles (PtNPs) Synthesis by Acid Phosphatase Mediated Eco-Benign Combined with Photocatalytic and Bioactivity Assessments.

Noble metal nanoparticles (NMNPs) are viable alternative green sources compared to the chemical available methods in several approach like Food, medical, biotechnology, and textile industries. The biological synthesis of platinum nanoparticles (PtNPs), as a strong photocatalytic agent, has proved as more effective and safer method. In this study, PtNPs were synthesized at four different temperatures (25 °C, 50 °C, 70 °C, and 100 °C). PtNPs synthesized at 100 °C were smaller and exhibited spherical morphology with a high degree of dispersion. A series of physicochemical characterizations were applied to investigate the synthesis, particle size, crystalline nature, and surface morphology of PtNPs. The biosynthesized PtNPs were tested for the photodegradation of methylene blue (MB) under visible light irradiations. The results showed that PtNPs exhibited remarkable photocatalytic activity by degrading 98% of MB only in 40 min. The acid phosphatase mediated PtNPs showed strong bacterial inhibition efficiency against S. aureus and E. coli. Furthermore, it showed high antioxidant activity (88%) against 1,1-diphenyl-2-picryl-hydrazil (DPPH). In conclusion, this study provided an overview of the applications of PtNPs in food chemistry, biotechnology, and textile industries for the deterioration of the natural and synthetic dyes and its potential application in the suppression of pathogenic microbes of the biological systems. Thus, it could be used as a novel approach in the food microbiology, biomedical and environmental applications.

Potent Acrylamide Determination in Food Products Using Ion-Selective Electrode Technique.

A potent selective acrylamide liquid sensor based on the reaction of acrylamide with 2-(5-Bromo-2-pyridylazo)-5-[N-n-Propyl-N-(3-Sulfopropyl) amino] aniline reagent is successfully designed. The characteristics slope (52.33 mV/decade), linearity usable range from 1.0 × 10-7-1.0 × 10-1 molar, limit of detection (1.6 × 10-8) molar, selectivity attitude to several inorganic cations, amino acids and sugars, time of response (8 s), lifetime (four months), pH effect on the electrode potential and the basic validation parameters were studied. The desirable pH applicable range was 3.0-6.5, and the restraint of the developed sensor is independent on this working pH range. The deployed electrode was effectively applied for rapid inexpensive analysis of acrylamide cations in food products with comparison to high-performance liquid chromatographic method and the results were agreeable with each other. The obtained data by the suggested electrode were treated statistically and compared with the various recently published acrylamide sensors.

Free Radical Scavenging Activity of Some Legumes Hulls Extract and Its Efficacy on Oil Oxidative Stability.

BACKGROUND: Synthetic antioxidants have toxigenic effects, there is therefore growing interest in substituting them with natural antioxidants. Attention is being focused on extracting them from agricultural industry residuals to minimize costs. Legume seed hulls could be cheap sources of such natural antioxidants. OBJECTIVE: This study aims to unravel potential free radical scavenging activity, antioxidant activity, and total phenolic and flavonoid contents of some legumes' hulls extracted by different solvents and evaluate their efficacy to enhance sunflower oil stability. METHOD: Legume hulls extracted by different solvents were evaluated for their antioxidant activity coefficient (AAC), free radical scavenging activity [by 2,2-diphenyl-1- picrylhydrazyl (DPPH)], and phenolic and flavonoids contents. The protection factor and induction periods (rancimat test) of the highest activity extracts were evaluated. RESULTS: Sunflower seed hull ethyl acetate extract, lupine seed hull ethanol extract, and mung bean hull petroleum ether extract exhibited stronger DPPH scavenging activity, AAC, and protection factor values than other solvents. Ethyl acetate extracts of sunflower seed hulls showed an antioxidant and scavenging activity close (P>0.05) to that detected for α-tocopherol. CONCLUSIONS: Legume hulls may possess strong free radical scavenging and antioxidant activity. The analogous effect between sunflower hull extract and α-tocopherol make it a potential, cheaper substitute of α-tocopherol in food systems. HIGHLIGHTS: The analogous effect between sunflower hull extract and α-tocopherol give it the potency to allow substitution at a concentration of 0.5% of sunflower hull ethyl acetate or 1% of lupine hull ethanol extract instead of 0.5% α-tocopherol to enhance induction periods and protection factors of sunflower oil.