Antimicrobial Properties of Lyophilized Extracts of Olive Fruit, Pomegranate and Orange Peel Extracts against Foodborne Pathogenic and Spoilage Bacteria and Fungi In Vitro and in Food Matrices.

Several novel antimicrobials with different concentrations of olive, pomegranate, and orange fruit pulp extracts were produced from agricultural byproducts and, after lyophilization, their antimicrobial activity and potential synergistic effects were evaluated in vitro and in food samples against foodborne pathogenic and spoilage bacteria and fungi. The Minimum Inhibitory of the tested bacteria was 7.5% or 10%, while fungi were inhibited at a concentration of 10% or above. The optical density of bacterial and yeast cultures was reduced to a different extent with all tested antimicrobial powders, compared to a control without antimicrobials, and mycelium growth of fungi was also restricted with extracts containing at least 90% olive extract. In food samples with inoculated pathogens and spoilage bacteria and fungi, the 100% olive extract was most inhibitory against E. coli, S. typhimurium, and L. monocytogenes in fresh burger and cheese spread samples (by 0.6 to 1.8 log cfu/g), except that S. typhimurium was better inhibited by a 90% olive and 10% pomegranate extract in burgers. The latter extract was also the most effective in controlling the growth of inoculated fungi (Aspergillus niger, Penicillium italicum, Rhodotorula mucilaginosa) in both yogurt and tomato juice samples, where it reduced fungal growth by 1-2.2 log cfu/g at the end of storage period. The results demonstrate that these novel encapsulated extracts could serve as natural antimicrobials of wide spectrum, in order to replace synthetic preservatives in foods and cosmetics.

Corn Silage Supplemented with Pomegranate (Punica granatum) and Avocado (Persea americana) Pulp and Seed Wastes for Improvement of Meat Characteristics in Poultry Production.

In the present study, pomegranate peels, avocado peels, and seed vacuum microwave extraction solid by-products were supplemented in corn silage in order to investigate the effects on meat quality and growth rate in broiler chicken. There were 50 broilers, divided in two groups, treated with experimental or usual feed for 43 days (group A: 25 broilers fed with avocado and pomegranate by-products and group B: 25 broilers fed with corn-silage used as control). The results showed that broiler chickens fed with a diet supplemented with a mixture of pomegranate avocado by-products (group A) showed significant differences in chicken leg meat quality, significantly improving the level of proteins and fatty acids content in breast and leg meat, respectively. More specific ω3 and ω6 fatty acids content were three times higher than in group B. Moreover, a protective effect on the decomposition of polyunsaturated fatty acids, induced by free radicals and presented in chicken meat, is based on the evaluation of lipid peroxidation by measuring thiobarbituric acid reactive substances. Pomegranate peels, avocado peels, and seed by-products appeared to have a slight reduction on meat production, while it was found to improve the qualitative chicken meat characteristics. Regarding the production costs, it was calculated that the corn-silage supplementation, used in this study, lead to a 50% lower cost than the commercial corn-silage used for the breeding of broilers.

Optimization of the Vacuum Microwave Assisted Extraction of the Natural Polyphenols and Flavonoids from the Raw Solid Waste of the Pomegranate Juice Producing Industry at Industrial Scale.

Pomegranate pomace (PP) is the solid waste produced in bulk by the pomegranate juice industry which is rich in polyphenols and flavonoids that can replace the hazardous chemical antioxidants/antimicrobials currently used in the agro-food and cosmetics sectors. In the present work, the vacuum microwave assisted extraction (VMAE) of natural antioxidants from raw pomegranate pomace was investigated and successfully optimized at an industrial scale. For the optimization of PP VMAE a novel, highly accurate response surface methodology (RSM) based on a comprehensive multi-point historical design was employed. The optimization showed that the maximum recovery of PP total polyphenols as well as total PP flavonoids were obtained at microwave power = 4961.07 W, water to pomace ratio = 29.9, extraction time = 119.53 min and microwave power = 4147.76 W, water to pomace ratio = 19.32, extraction time = 63.32 min respectively. Moreover, the optimal VMAE conditions on economic grounds were determined to be: microwave power = 2048.62 W, water to pomace ratio = 23.11, extraction time = 15.04 min and microwave power = 4008.62 W, water to pomace ratio = 18.08, extraction time = 15.29 min for PP total polyphenols and PP total flavonoids respectively. The main conclusion of this study is that the VMAE extraction can be successfully used at industrial scale to produce, in economic manner, high added value natural extracts from PP pomace.

Optimization of Vacuum-Microwave-Assisted Extraction of Natural Polyphenols and Flavonoids from Raw Solid Waste of the Orange Juice Producing Industry at Industrial Scale.

Orange pomace (OP) is a solid waste produced in bulk as a byproduct of the orange juice industry and accounts for approximately 50% of the quantity of the fruits processed into juice. In numerous literature references there is information about diverse uses of orange pomace for the production of high-added-value products including production of natural antioxidant and antimicrobial extracts rich in polyphenols and flavonoids which can substitute the hazardous chemical antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work and for the first time, according to our knowledge, the eco-friendly aqueous vacuum microwave assisted extraction of orange pomace was investigated and optimized at real industrial scale in order to produce aqueous antioxidant/antimicrobial extracts. A Response Surface Optimization methodology with a multipoint historical data experimental design was employed to obtain the optimal values of the process parameters in order to achieve the maximum rates of extraction of OP total polyphenols and/or total flavonoids for economically optimum production at industrial scale. The three factors used for the optimization were: (a) microwave power (b) water to raw pomace ratio and (c) extraction time. Moreover, the effectiveness and statistical soundness of the derived cubic polynomial predictive models were verified by ANOVA.

Effects of Dietary Grape Pomace Supplementation on Performance, Carcass Traits and Meat Quality of Lambs.

BACKGROUND/AIM: A previous study revealed that the inclusion of grape pomace (GP) in the diet for growing lambs had beneficial effects on the redox status and fecal microbiota. Herein, we investigated the effect of GP inclusion on performance, carcass traits and fatty acid composition of meat. MATERIALS AND METHODS: In the experimental trial of 55 days, lambs were fed with standard or diet supplemented with GP. Performance, carcass traits and fatty acid profile of quadriceps muscle were assessed. RESULTS: GP inclusion in the diet improved growth performance, since the average daily gain was significantly increased by 2-fold in GP group. Regarding the fatty acid composition of meat, GP inclusion significantly increased the content of long chain n-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, and reduced the n-6/n-3 ratio compared to the control group. CONCLUSION: GP supplementation in lamb diet may improve performance and may have beneficial effects on meat quality.

Antibacterial and antioxidant activity of different types of honey derived from Mount Olympus in Greece.

The aim of the present study was to examine the antioxidant and antibacterial activity of 21 types of honey derived from Mount Olympus (Mt. Olympus), a region with great plant biodiversity. The antibacterial activity was examined against the growth of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) by the agar well diffusion assay and the determination of the minimum inhibitory concentration (MIC). The antioxidant activity was assessed by using the 2,2­diphenyl­1­picrylhydrazyl (DPPH) and 2,2'­azino­bis(3­ethylbenzothiazoline­6­sulphonic acid (ABTS•+) free radical scavenging assays. These activities were compared to Manuka honey which is used as an alternative medicine. The results revealed that all tested honey types exhibited antibacterial activity against S. aureus and P. aeruginosa. The MIC of the tested honey types against S. aureus ranged from 3.125 to 12.5% (v/v), while MIC of Manuka honey was determined to be 6.25% (v/v). The MIC values of the tested honey types against P. aeruginosa ranged from 6.25 to 12.5% (v/v) and the MIC of Manuka honey was determined at 12.5% (v/v). Moreover, the results suggested that the presence of hydrogen peroxide and proteinaceous compounds in the honey types accounted, at least in part, for the antibacterial activity. In addition, the total polyphenolic content (TPC) of the honey types seemed to contribute to the antibacterial activity against P. aeruginosa. Furthermore, some of the tested honey types exhibited potent free radical scavenging activity against DPPH and ABTS•+ radicals, which was greater than that of Manuka honey. The results indicated that not only the quantity, but also the quality of the polyphenols were responsible for the antioxidant activity. Moreover, four honey types exhibiting great antioxidant activity were converted to powder using a freeze drying method. The results indicated that following conversion to powder all honey types, apart from one, retained their antioxidant activity, although their TPC was reduced. On the whole, and at least to the best of our knowledge, the present study is the first that extensively examined the bioactivities of different types of honey derived from Mt. Olympus.

Nutritional Value, Chemical Characterization and Bulb Morphology of Greek Garlic Landraces.

Garlic (Allium sativum L.) is an important vegetable crop throughout the world. In Greece there are many areas which have specialized in garlic cultivation through the last decades, considered the main production areas. However, despite the significance of garlic as a food product and the high annual income of this crop, there is a decreasing trend in total cultivated area in Greece, and the local landraces are gradually neglected in favor of new imported genotypes. In the present study, garlic genotypes (local landraces/varieties, imported genotypes, commercial cultivars) from the main production regions of Greece were assessed for their chemical composition and quality (total soluble solids, dry matter content, nutritional value, mineral composition, organic acids, fatty acids content and free sugars content), and bulb morphology. The results of the present study showed significant diversity in quality features and bulb morphology, not only between the genotypes from different growing regions, but also between those of the same region. This result is interesting since it could be implemented for further improvement and valorization of this important vegetable crop through extensive breeding programs within the framework of sustainability and genetic, material conservation.

Enhancement of Antioxidant Mechanisms and Reduction of Oxidative Stress in Chickens after the Administration of Drinking Water Enriched with Polyphenolic Powder from Olive Mill Waste Waters.

The aim of the study was to examine the effects of a polyphenolic powder from olive mill wastewater (OMWW) administered through drinking water, on chickens' redox status. Thus, 75 chickens were divided into three groups. Group A was given just drinking water, while groups B and C were given drinking water containing 20 and 50 µg/ml of polyphenols, respectively, for 45 days. The antioxidant effects of the polyphenolic powder were assessed by measuring oxidative stress biomarkers in blood after 25 and 45 days of treatment. These markers were total antioxidant capacity (TAC), protein carbonyls (CARB), thiobarbituric acid reactive species (TBARS) and superoxide dismutase activity (SOD) in plasma, and glutathione (GSH) and catalase activity in erythrocytes. The results showed that CARB and TBARS were decreased significantly in groups B and C, and SOD decreased in group B compared to that in group A. TAC was increased significantly in group C and GSH was increased in group B, while catalase activity was increased in groups B and C compared to that in group A. In conclusion, this is the first study showing that supplementation of chickens with polyphenols from OMWW through drinking water enhanced their antioxidant mechanisms and reduced oxidative stress-induced damage.

Novel feed including bioactive compounds from winery wastes improved broilers' redox status in blood and tissues of vital organs.

Currently, there is a great interest in the production of animal feed with antioxidant activity. The aim of this study was to examine the potential antioxidant effects of a feed supplemented with grape pomace (GP), a winery by-product with high environmental load, in chickens. Broilers of 15 days post birth were separated into two groups fed either with standard diet or with diet supplemented with GP for 35 days. Blood and tissues collections were performed after feeding for 15 and 35 days with the experimental diet (i.e. at 30 and 50 days post birth). Free radical toxicity markers, namely thiobarbituric acid reactive substances, protein carbonyls, total antioxidant capacity, reduced glutathione, catalase activity and rate of H2O2 decomposition were determined in blood and tissues of vital organs. The results indicated that feed supplemented with GP decreased oxidative stress-induced toxic effects and improved chickens' redox status, and so it may also improve their wellness and productivity. On the other hand, this exploitation of GP may solve problems of environmental pollution in areas with wineries.

Assessment of Fatty Acid Allocation in Plasma and Tissues in Piglets, Using Feed Supplemented with Byproducts from Processed Olive Mill Wastewater.

BACKGROUND/AIM: A previous study revealed the improvement of redox status in blood and tissues of young piglets (ablactation period), that consumed feed containing polyphenolic additives from byproducts of processed olive mill wastewater (OMWW). The polyphenolic additives strengthened the antioxidant defense of the piglets. Herein we analyzed the fatty acid (FA) composition of these animals in various tissues. MATERIALS AND METHODS: The steps followed during the analysis were: Preparation and isolation of byproducts containing polyphenolic compounds from OMWW processing, silage and piglet feed preparation, blood and tissue collection, fatty acid methyl esters synthesis and GC/MS analysis. RESULTS: The young piglets, that consumed feed containing polyphenolic additives from byproducts of processed OMWW, were found to have a decreased ω6/ω3 ratio, compared to samples of the control group. For example, in the quadriceps tissue the control group has a ω6/ω3 ratio of 10.1, while in the polyphenolic group this ratio was decreased to 2.93. Regarding the ratio of UFA/SFA, no significant differences were observed. Finally, the polyphenolic group exhibited almost in all tissues lower values of the ratio of PUFA/MUFA than the control group.

Feed supplemented with polyphenolic byproduct from olive mill wastewater processing improves the redox status in blood and tissues of piglets.

In the present study, a polyphenolic byproduct from olive mill wastewater (OMWW) was used for making piglet feed with antioxidant activity. For examining the antioxidant capacity of the feed, 30 piglets of 20 d old were divided into two groups receiving basal or experimental feed for 30 d. Blood and tissue samples were drawn at days 2, 20, 35 and 50 post-birth. The tissues collected were brain, heart, kidney, liver, lung, quadriceps muscle, pancreas, spleen and stomach. The antioxidant effects of the experimental feed were assessed by measuring oxidative stress biomarkers in blood and tissues. The oxidative stress markers were total antioxidant capacity (TAC), glutathione (GSH), catalase activity (CAT), protein carbonyls (CARB) and thiobarbituric acid reactive species (TBARS). The results showed that piglets fed with diet supplemented with OMWW polyphenols had significantly increased antioxidant mechanisms in blood and the majority of the tested tissues as shown by increases in TAC, CAT and GSH compared to control group. Moreover, piglets fed with the experimental feed exhibited decreased oxidative stress-induced damage to lipids and proteins as shown by decreases in TBARS and CARB respectively. This is the first study in which OMWW polyphenols were used for making pig feed with antioxidant activity.

Feed supplemented with byproducts from olive oil mill wastewater processing increases antioxidant capacity in broiler chickens.

In the present study, a ceramic membrane microfiltration method was used for the separation of two liquid products, the downstream permeate and the upstream retentate, from olive mill wastewater (OMWW). These liquid products were examined for their antioxidant activity by incorporating them into broilers' feed. Twenty four broilers 13 d old were divided into two feeding groups receiving supplementation with OMWW retentate or permeate for 37 d. Blood was drawn at 17, 27 and 37 d, while tissues (muscle, heart, liver) were collected at 37 d. The antioxidant effects were assessed by measuring oxidative stress biomarkers in blood and tissues. The results showed that broilers given feed supplemented with OMWW retentate or permeate had significantly lower protein oxidation and lipid peroxidation levels and higher total antioxidant capacity in plasma and tissues compared to control group. In both OMWW groups, catalase activity in erythrocytes and tissues was significantly increased compared to control group. OMWW retentate administration increased significantly GSH in erythrocytes in broilers with low GSH, although both OMWW products significantly reduced GSH in broilers with high GSH. Thus, it has been demonstrated for the first time that supplementation with OMWW processing residues could be used for enhancing broilers' redox status.