Effect of Natural Antioxidants from Fruit Leaves on the Oxidative Stability of Soybean Oil during Accelerated Storage.

Plant by-products are safe, sustainable, and abundant natural antioxidant sources. Here we investigated the antioxidant activity of a mixture of lyophilized pomegranate, guava, and grape (PGG) leaves water extract (1:1:1) and examined its ability to retard the rancidity of soybean oil during accelerated storage at 65 °C for 30 days. To achieve this, we evaluated the oxidative stability of soybean oil enriched with PGG extract at 200, 400, and 800 ppm. We also compared the effect of PGG extract with butylated hydroxytoluene (BHT) (400/100 ppm) with that of only BHT (200 ppm). We observed that 8.19 and 1.78 µg/mL of the extract could scavenge 50% of DPPH• and ABTS•, respectively, indicating its enhanced antioxidant activity. Enriching soyabean oil with the extract at 800 ppm improved its oxidative stability by reducing the acid value to 1.71 mg/g and the total oxidation to 99.87 compared to 2.27 mg/g and 150.32 in the raw oil, respectively. Moreover, PGG-800 ppm inhibited oxidation by 46.07%. Similarly, PGG-400 ppm reinforced BHT (100 ppm) to provide oxidative stability as BHT (p > 0.05), with TOTOX values of 87.93 and 79.23, respectively. PGG-800 ppm and PGG/BHT mix potently inhibited the transformation of polyunsaturated fatty acids into saturated ones. Therefore, the PGG extract might be an efficient substitute for BHT (partially or totally) during industrial processes.

Evaluation of the Prevalence of Staphylococcus aureus in Chicken Fillets and Its Bio-Control Using Different Seaweed Extracts.

This study aims to assess the occurrence of Staphylococcus aureus in chicken fillets and to control its growth using various lyophilized seaweed extracts (i.e., Halimeda opuntia (HO), Actinotrichia fragilis, and Turbinaria turbinata) by an agar disk diffusion assay in vitro. Results showed that prevalence of S. aureus in breast and thigh samples reached of 92% and 84%, respectively. Lyophilized HO extract was the only seaweed that showed the antibacterial activity against S aureus with a significant difference at p < 0.05. The minimum inhibitory concentration (MIC) of HO extract was 1.5%, with an inhibition zone of 8.16 ± 0.73 mm. Regarding 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, IC50 was recorded at 55.36 µg/mL, whereas cytotoxic IC50 of the lyophilized HO extract on peripheral blood mononuclear cells (PBMCs) was 33.7 µg/mL; a higher IC50 of HO extracts permits their use as a safe food additive in meat products. Moreover, total phenolic compounds and total flavonoids compounds recorded 20.36 ± 0.092 and 16.59 ± 0.029 mg/mL, respectively. HPLC analyses of phenolic compounds profiles exhibited many bioactive substances and the higher ratio was daidzein with 10.84 ± 0.005 µg/mL and followed by gallic acid with a value of 4.06 ± 0.006 µg/mL. In a challenge study, chicken fillet (CHF) experimentally inoculated with S. aureus (ST) and treated with the lyophilized HO algal extract at 4% and 6% (CHF/ST/HO) showed a complete reduction of S. aureus count on the 6th and 4th days in chicken fillet stored at 4 °C, respectively. Moreover, CHF/ST/HO at 4% and 6% of HO extract enhanced the sensory attributes of grilled un-inoculated chicken fillet. Thus, lyophilized HO extracts are promising antibacterial and antioxidant candidates in the chicken meat industry.

Detoxification of Aflatoxin B1 and Ochratoxin A Using Salvia farinacea and Azadirachta indica Water Extract and Application in Meat Products.

Seventy-five samples of selected meat products, including luncheon, beef burger, sausage, basterma, and kofta, were collected from Alexandria and New Borg El-Arab cities (Egypt). The samples were subjected to mycological examination as well as for detection of aflatoxin B1 (AFB1) and ochratoxin A (OTA) residues. Besides, the study evaluated the effect of aqueous leaf extracts from mealycup sage (Salvia farinacea) and neem (Azadirachta indica), individually and in combination, on the growth of human pathogens Aspergillus parasiticus and Aspergillus flavus producing AFB1, as well as Aspergillus ochraceus and Aspergillus niger which produce OTA. The obtained results revealed that sausage samples had the highest mould count with a mean value of 13.20×102/g, followed by basterma samples 12.05×102/g, then beef burger 7.39×102/g. In contrast, luncheon and kofta samples had the lowest count with a mean value of 5.51×102/g and 2.82×102/g. The findings revealed the antifungal potential of tested extracts. The total inhibition of A. parasitcus and A. niger growth was observed at 2 mg/mL of the combined extract. Salvia farinacea extract had the highest total phenolic content and total flavonoid content with a value of 174.1 and 52.6 mg g-1, respectively. Rutin was the major phenolic component in neem and combined extracts, accounting for 19123 and 8882 µg/g, respectively. Besides, the study investigated detoxification of AFB1 and OTA using combined extract in albino rats. The results confirmed the convenient and safe use of Salvia farinacea and Azadirachta indica extract and their combination as natural antifungal and antioxidant agents. The combined extract could be used as a natural preservative in food processing to control or prevent contamination.

Nutritional Evaluation of Beetroots (Beta vulgaris L.) and Its Potential Application in a Functional Beverage.

Beetroot is a good source of minerals, fibers, and bioactive components. The present research work was conducted to evaluate the nutritional quality of beetroots (juice, peels, leaves and pomace) enhancing the extracted bioactive components, and developing a functional probiotic beverage. Chemical composition and minerals content of beetroot parts were estimated. The bioactive components were extracted by instant extraction method (IEM) and overnight extraction method (at -20°C) (OEM) to determine total phenolics, flavonoids, and DPPH inhibition ratio. The extracted beetroot juice was mixed with milk for valorization of the beverage nutritional value and fermented with LA-5 and ABT-5 cultures to create a novel functional beverage. Chemical composition, minerals content, and bioactive components of beverages were estimated. The leaves exhibited the highest calcium content (1200 mg/100g). Juice showed the highest amount of all minerals except for calcium and magnesium. Overnight extraction method (OEM) increased the antioxidant activity in peels and stems. Natural juice exhibited the highest activity compared to extracts. Fermentation of beet-milk beverage with LA-5 and ABT-5 cultures enhanced the beverage taste, flavor, and antioxidant capacity. Beetroot wastes and juice comprise a valuable nutritional source. Fermentation improved the nutritional value of beetroot and the acceptability of the product.

Anti-Escherichia coli O157:H7 as Natural Preservative to Control and Prevent Food Contamination in Meat and Fish Products.

BACKGROUND AND OBJECTIVE: Shiga toxin-producing Escherichia coli O157:H7 is a troubled foodborne pathogen associated with contamination of meat, fish and poultry. The present work aimed to evaluate plant extracts as natural preservatives anti- Escherichia coli O157:H7 in meat and fish products. MATERIALS AND METHODS: Antibacterial activity and minimum inhibitory concentrations (MICs) of seven herbal plants, clove, marjoram, sage, pomegranate peel, turmeric, Cassia fistula and black pepper and their different 6 mixes were examined against Escherichia coli O157:H7. Phytochemical qualitative analysis, phenolic compounds (HPLC), total phenolic, total flavonoid contents and antioxidant activities of individual extracts and their 6 mixes were evaluated. Combination Mix 5 extract was applied on meat and fish-fillet, then its antimicrobial effect against E. coli O157:H7 and sensory evaluation were assessed. RESULTS: Five extracts exhibited good antibacterial activity against Escherichia coli O157:H7. The greatest inhibition zone was recorded by clove aqueous extract (25 mm). Mix 5 (clove, sage, pomegranate and Cassia fistula) showed the highest inhibition with MIC of 3.0 mg mL-1. This mix exhibited strong anti-bactericidal effect against E. coli O157:H7 in meat and fish-fillet products throughout 8 days of cold storage (4°C). The sensory evaluation revealed that Mix 5 was acceptable by panelists with concentration of 0.50% in beef burgers and 0.25% in fish-fillet. CONCLUSION: This study suggests that the use of herbal extracts provide antibacterial potentials against food pathogens in meat and fish products.

Commercial probiotic cell-free supernatants for inhibition of Clostridium perfringens poultry meat infection in Egypt.

Prevalence of C. perfringens in Egyptian poultry causes severe economic losses in poultry industry which evokes innovative solutions for enhanced future prospects. The objective of this study was to employ probiotic cell-free supernatants for inhibition of Clostridium perfringens in poultry meat to control its prevalence in the Egyptian market. Four probiotic strains, Lactobacillus rhamnosus EMCC 1105, Lactobacillus fermentum EMCC 1346, Pediococcus acidilactici EMCC 1690 and Lactobacillus delbrueckii subsp. lactis EMCC supernatants' anti-clostridial effect was assessed using agar disk diffusion assay, while antioxidant potentials and phenolic compounds were determined through colorimetric methods; DPPH, Folin-Ciocalteu and High Performance Liquid Chromatography (HPLC). Fifteen out of 50 chicken samples collected from Alexandria Governorate, Egypt, with percent of 30%, showed positive results for presence of C. perfringens with counts reached 3.71 ±â€¯0.25 Log10 CFU/g. L. rhamnosus EMCC 1105 showed higher anti-clostridial potentials with inhibition zone diameter of 30  mm at concentration of 100 mg/ml and Minimum Inhibitory Concentration (MIC) of 6.25 mg/ml. Furthermore, L. rhamnosus revealed the best antioxidant potentials with IC50 46.59 µg/ml, total phenolic content 172.08 mg/ml and total flavonoid content 17.22 mg/ml. When different concentrations of its supernatant 25, 50 and 100 mg/g were applied, 100 mg/g were able to eliminate C. perfringens EMCC1574 from chicken meat on the 4th day of cold storage. For antagonistic potentials against clostridial infections, this probiotic strain could be recommended for further trials in other applications targeting food safety.

Does biopolymers composition in seeds contribute to the flax resistance against the Fusarium infection?

Over the last decades, the cultivation of fibrous flax declined heavily. There are number of reasons for that fact; one of them is flax susceptibility to the pathogen infection. Damages caused mainly by fungi from genus Fusarium lead to the significant losses when cultivating flax, which in turn discourage farmers to grow flax. Therefore, to launch the new products from flax with attractive properties there is a need to obtain new flax varieties with increased resistance to pathogens. In order to obtain the better quality of flax fiber, we previously generated flax with reduced pectin or lignin level (cell wall polymers). The modifications altered also plants' resistance to the Fusarium infection. Undoubtedly, the plant defense system is complex, however, in this article we aimed to investigate the composition of modified flax seeds and to correlate it with the observed changes in the flax resistance to the pathogen attack. In particular, we evaluated the content and composition of carbohydrates (cell wall polymers: pectin, cellulose, hemicelluloses and mucilage), and phenylpropanoid compounds (lignin, lignans, phenolics). From the obtained results we concluded that the observed changes in the vulnerability to pathogens putatively correlate with the antioxidant potential of phenylpropanoids accumulated in seeds, seco-isolariciresinol and coumaric acid diglycosides in particular, and with pectin level as a carbon source for pathogens. Surprisingly, relatively less important for the resistance was the physical barrier, including lignin and cellulose amount and cellulose structure. Certainly, the hypothesis should be verified on a larger number of genotypes.