Green-sustainable extraction techniques for the recovery of antioxidant compounds from "citrus Limon" by-products.

In this work, optimized techniques of conventional, ultrasound and microwave-assisted extraction were applied for the recovery of antioxidant compounds from lemon by-products (Citrus limon L). Specifically, the effect of solvent, temperature, microwave power, time and their interaction on the extraction was investigated. Among the tested solvents, the hydroalcoholic mixture (ethanol:water, 50:50) was the optimal one for all extraction techniques: in particular assisted by ultrasounds at 70 °C for 30 minutes (total phenolic content: 6.93 mg GAE g-1, total flavonoids: 2.07 mg CE g-1, ABTS assay: 18.36 µM TE g-1). Also, the other techniques allowed to obtain valuable extracts, although with relative lower amounts. The analyses of individual phenols revealed hesperidin and eriocitrin as the main compounds (respectively about 1650 and 1150 mg kg-1) after ultrasound assisted and conventional extraction. Results of this work can be useful to valorize an industrial by-product by sustainable techniques for the high-added value substances recovery.

Antioxidant quantification in different portions obtained during olive oil extraction process in an olive oil press mill.

BACKGROUND: Different antioxidant compounds are generally transferred from olives to olive oil during the production process. This work characterized the principal total bioactive compounds (tocopherols and phenols) in olives, olive oil and by-products of four cultivars grown in Calabrian areas (southern Italy), considering the effect of harvesting period. Antioxidant capacity, total and individual phenolic compounds were also analysed. RESULTS: Drupes, olive paste, pomace and olive wastewater showed similar phenolic compounds, while olive oil possessed a different composition, suggesting that phenols are not only transferred from drupe to oil, but also they change during oil production. Tocopherols varied among cultivars and harvesting period: generally, they were more abundant in samples produced in the first harvesting period. Qualitative and quantitative differences in phenolic composition and antioxidant activity were significantly found among cultivars in all the matrices. CONCLUSION: The highest amount of total phenolic antioxidants ended up in olive wastewater with variability due to the olive cultivar, while only a small part of them finished in the oil. This work shows evidence that the availability of bioactive compounds in different portions from the olive oil extraction belong to different varietal origins. In particular, new information was acquired on Ottobratica Calipa, a new olive clone, that produced an olive oil with an interesting antioxidant amount. © 2020 Society of Chemical Industry.

Shelf life extension of mozzarella cheese packed in preserving liquid with calcium lactate and bergamot juice concentrate.

Traditional Mozzarella is a fresh cheese produced in Italian local market without additives that shows a short shelf life of about 5 d. This work tested the use of natural additives (bergamot juice concentrate-BJ and calcium lactate-CL) in preserving liquid for a Mozzarella cheese with the aim to extend its shelf life, regarding the microbial growth and overall cheese quality. Results of qualitative analyses showed that the preserving liquid with the mix of BJ and CL promoted an extension of mozzarella shelf life up to 20 d. A slightly reduced growth of Pseudomonas species was evidenced after 5 d of storage, whereas no inhibition of lactic acid bacteria was observed for the storage period. Moreover, mozzarella cheese packed in mixed preserving liquid possessed better textural properties, evidenced by the lowest proteolysis index measured after 13 d of storage, and a good antioxidant activity.

Metabolites response to onion yellow dwarf virus (OYDV) infection in 'Rossa di Tropea' onion during storage: a 1 H HR-MAS NMR study.

BACKGROUND: Plant viral infections induce changes in metabolic components in the host plant, with potential effects on compositional, organoleptic and storability features of agricultural products. Identification of modulated metabolites may provide clues concerning pathways implementing responses in plant-pathogen interactions. A time course study of metabolic fingerprinting of onion yellow dwarf virus (OYDV)-infected versus healthy 'Rossa di Tropea' onion bulbs was performed using proton high-resolution magic angle spinning nuclear magnetic resonance (1 H HR-MAS NMR) and ultra-performance liquid chromatography (UPLC), providing an overview of the metabolic state of the bulb in response to OYDV infection during storage. RESULTS: Metabolites accumulated/depleted upon infection were identified, belonging to flavonoid, saccharide, amino acid and organic acid classes. A decrease in quercetin glucosides content and antioxidant activity was observed in infected bulbs; some amino acids (Arg, Asn, Phe, Val) accumulated, while others were depleted (Leu); for some metabolites, a bimodal time-course was observed during storage (Glc, Lys). Virus interference on metabolic pathways, and the effects of the metabolic shift on edible product storability, organoleptic and nutritional quality were discussed. CONCLUSIONS: OYDV infection induces a metabolic shift in 'Rossa di Tropea' onion during bulb storage, involving several pathways and affecting storability and organoleptic and nutritional quality of bulbs at marketable stage. © 2020 Society of Chemical Industry.

Evaluation of different salted governing liquids on shelf life extension of lacto-fermented mozzarella cheese.

The effect of different governing liquids on qualitative parameters of lacto-fermented mozzarella cheeses were studied. 0.6% calcium lactate solution maintained the quality of mozzarella cheese for microbial, color and textural properties and prolonged its shelf life up to 18 days, also improving its antioxidant activity by Trolox equivalent antioxidant capacity and Oxygen radical absorbance capacity assays.

Quality of shredded carrots minimally processed by different dipping solutions.

The whiteness of shredded carrots is generally caused by enzymatic reactions after removal of natural protection during the minimal processing. Moreover, the use of chlorinated solution in sanitizing step of processing, promotes the formation of halogenated by-products, with correlated environmental and health risks in processing areas. This study investigated the effect of different acidic solutions on the quality of shredded carrots during the storage at two refrigerated temperatures (4 °C and 7 °C), as alternative agents to chlorine in food industry. Carrots dipped in 1.5% citric acid solution did not present colour variation at both storage temperatures. Moreover they showed the lowest microbial charge after processing and during storage at 4 °C. Carrots dipped in 0.5% citric acid + 0.05% ascorbic acid + 0.05% calcium chloride evidenced lower PAL and POD activities during the storage respect to the other tested samples. Therefore, the dipping of shredded carrots in acidic solutions, as alternative sanitizers to chlorine, contributed to preserve their quality, also controlling the whiteness index of carrots' surface. In particular, the dipping in 1.5% citric acid extended the shelf life of shredded carrots up to 14 days of storage at 4 °C.

Antioxidant activity shown by olive pomace extracts.

In this study, the effects of experimental variables such as type of solvent, sample/solvent ratio, and time of extraction have been evaluated to individuate the best results in phenolic recovery by Olive Pomaces (OP) belonging to Carolea and Ottobratica cultivars. Folin-Ciocaulteu procedure and DPPH and ABTS assays were used, respectively, for total phenol quantification and total antioxidant activity of pomace extracts. The ethanol/water mixture was resulted the most efficient extraction solvent for both olive cultivars. The highest amount of phenolic compounds (171 ± 4 mg of gallic acid 100 g-1 of dry pomace) was obtained after extraction at 120 min with 2:1 solvent/OP (v/w) of Ottobratica Olive Pomace. The recovery of phenol compounds from olive wastes increases the sustainability of sector, allowing obtaining an extract that could be a suitable alternative in the food industry to the use of synthetic antioxidants in order to improve the quality of foods.

Qualitative variations on Calabrian Provola cheeses stored under different packaging conditions.

Calabrian Provola cheese, an Italian typical dairy product, is commonly sold unwrapped with an expiry date of 45 d. The influence of different packagings and subsequent storage at 4 and 7 °C on maintaining cheese quality and prolonging its shelf life was evaluated. The following packaging systems were used: Polyamide/Polyethylene pouch under vacuum; Polyethylene/Polyethylene terephthalate lid over a Polyethylene/Ethylene vinyl alcohol/Polyvinyl Chloride + Polyvinyl alcohol thermoformed tray; Polyethylene/Ethylene vinyl alcohol/Polyamide/Polyethylene pouch. Concerning the two last systems, cheeses were packaged in a modified atmosphere (70:30 N2:CO2). All studied packaging prolonged Calabrian Provola cheese shelf life to 65 d. In particular, the packaging in modified atmosphere with Polyethylene/Ethylene vinyl alcohol/Polyamide/Polyethylene pouch preserved Provola cheeses best, not only showing a decrease of the original total microbial count but also showing the lowest peroxide value and hardness at both temperatures of storage. The results of this study will help local Italian firms to expand their business in more distant markets.

Impact of Antioxidant-Enriched Edible Gel Coatings and Bio-Based Packaging on Cherry Tomato Preservation.

This research investigates the effects of using edible gel coatings and bio-based packaging materials on extending the shelf life of cherry tomatoes. Two edible gel coatings (guar gum and guar gum +5% of a lemon (Citrus limon (L.) Osbeck pomace extract obtained in the research laboratory) were applied on cherry tomatoes, then they were packaged in bio-based materials (cellulose tray + PLA lid). Guar gum, glycerol, sorbitol, extra virgin olive oil, and tween 20 were used in coating formulation. Uncoated tomatoes packed in bio-based materials and conventional plastic (PET trays + lid) were tested as a control. Samples were stored for 45 days at 20 °C and their quality parameters were evaluated. Coated tomatoes maintained firmness and weight, and the enriched coated samples showed a significant increase in phenol content, derived from the antioxidant extract. Samples packed in PET showed a sensory unacceptability (<4.5) after 45 days correlated with a greater decline in firmness (from 10.51 to 5.96 N) and weight loss (from 7.06 to 11.02%). Therefore, edible gel coating and bio-based packaging proved to be effective in maintaining the overall quality of cherry tomatoes for 45 days, offering a promising approach to reduce plastic polymer use and food waste.

Influence of the Mozzarella Type on Chemical and Sensory Properties of "Pizza Margherita".

BACKGROUND: According to Neapolitan Pizza Traditional Specialty Guaranteed (TSG) regulation, Mozzarella di Bufala Campana and Fiordilatte mozzarella are the exclusive cheeses to be used, together with tomato and extra virgin olive oil (EVOO), to season pizza in the "Margherita" variant. However, the so-called "Pizza mozzarella", that is a diary product having lower moisture content and a longer shelf life than Mozzarella di Bufala Campana and Fiordilatte mozzarella, is widely used in many pizzerias, both in Italy and abroad. Therefore, we investigated its quality, in comparison with Mozzarella di Bufala and Fiordilatte mozzarella, as well as its effect on the quality of the Margherita pizza. METHODS: Chemical and sensory analyses were conducted on mozzarella samples and on baked pizza topping samples. RESULTS: The results revealed a better quality of pizza with Mozzarella di Bufala and Fiordilatte mozzarella for their higher antioxidant activity, oxidative stability and lower amount of undesired volatile compounds. CONCLUSIONS: The use of Mozzarella di Bufala and Fiordilatte mozzarella in the preparation of Margherita pizza improves its quality, especially if these mozzarella types are combined with other high-quality ingredients, namely tomato sauce and EVOO, characterized by the presence of antioxidant compounds (e.g., α-tocopherol not affected by the heat treatment of pizza baking.

Evaluation of the Efficacy of Antioxidant Extract from Lemon By-Products on Preservation of Quality Attributes of Minimally Processed Radish (Raphanus sativus L.).

The aim of this work was to enhance the use of a food-grade antioxidant extract obtained from lemon processing byproducts (peel, pulp and seeds) to extend the shelf life of minimally processed radishes. The extract (LPE) was previously characterized in terms of total phenolic (6.75 ± 0.34 mg GAE g-1 d.w.) and flavonoid content (2.04 ± 0.09 mg CE g-1 d.w.) and antioxidant activity, and eriocitrin and hesperidin were identified as the most prevalent phenolic compounds by a UHPLC system. The effects of different dipping aqueous solutions (UCR, DRa, DRb) and alginate-based edible coating formulations (CRc, CRd) with and without the antioxidant extract were studied on the quality parameters of minimally processed radishes, characterized regarding their microbiological and physicochemical characteristics for up to 14 days at 3 °C. The coating formulated with LPE delayed the radish respiration process, as well as resulting in less color variation (ΔE < 3) and reduced mesophilic aerobic count values (4.49 ± 1.43 log CFU g-1), proving the effectiveness of LPE as a value-added ingredient in developing post-harvest strategies to prolong the shelf life of minimally processed vegetables. Indeed, coated samples without the extract showed a clear development of rotting, which led to the end of their shelf life on their 7th day of storage.

Effect of Edible Coating Enriched with Natural Antioxidant Extract and Bergamot Essential Oil on the Shelf Life of Strawberries.

In this study, the effects of the application of edible coatings on the shelf life of the strawberry were evaluated, with the aim of extending the fruit's availability and shelf life while preserving its qualitative characteristics. In particular, the application of edible coatings enriched with a natural antioxidant to strawberries was evaluated for their physicochemical, microbial, and structural properties, during a storage period (up to 14 days) at refrigerated temperature. The experimental plan provided the formulation for edible coatings enriched with different concentrations of a natural antioxidant extract obtained from bergamot (Citrus bergamia Risso) pomace (1, 2.5, and 5%), bergamot essential oil (0.1% v/v and 0.2% v/v), and a synthetic antioxidant, butylated hydroxytoluene (BHT, 100 ppm). Moreover, a control test with untreated strawberries was considered. The enriched gum Arabic coatings provided good results related to the preservation of the qualitative parameters of the strawberries. The samples coated with the antioxidant extract (2.5%, sample D) and bergamot essential oil (0.1%, sample F) showed the best maintenance of the qualitative parameters after 14 days, showing lower decay rates (36% D and 27% F), good acceptability by consumers (between 5 and 6), and good retention of ascorbic acid (>30 mg 100 g-1).

Efficacy of Pectin-Based Coating Added with a Lemon Byproduct Extract on Quality Preservation of Fresh-Cut Carrots.

The effect of an edible pectin-based coating supplemented with a lemon byproduct extract on the quality attributes of fresh-cut carrots was studied. Color, hardness, microbial growth, respiratory activity, and antioxidant properties of fresh-cut carrots were studied during 14 days of storage at 4 °C. The application of a pectin-based coating containing a lemon byproduct extract preserved carrots' physiological parameters, reduced their physiological activity and, thus, delayed senescence. This aspect was also confirmed by the reduced O2 consumption of the coated carrots due to the slowing down of the product's metabolic reactions. Moreover, coated carrots were characterized by limited changes in colour (ΔE < 3) and white-blush development on both cortical tissue and vascular cylinder, and the presence of calcium chloride in the coating formulation helped to maintain carrots' hardness throughout storage. In addition, treatment with pectin-based coating and lemon byproduct extract improved microbiological stability of fresh-cut carrots, showing the lowest value of total bacterial count immediately after treatment (2.58 log CFU g−1). This kind of treatment also resulted in a significant preservation of valuable compounds (17.22 mg GAE 100 g−1) and antioxidant activity level (289.49 µM Trolox 100 g−1), reducing the wounding stress induced by processing operations for at least ten days.

Effect of Oil Type Used in Neapolitan Pizza TSG Topping on Its Physical, Chemical, and Sensory Properties.

BACKGROUND: According to the regulations of the Neapolitan Pizza TSG, extra virgin olive oil must be exclusively used as topping ingredient, together with tomato for pizza marinara-type production. As, often deliberately, other oils are replaced by pizza makers for economical and organoleptic purposes, the present study was conducted to analyze the quality of pizza depending on the oil typology used. METHODS: Chemical and sensory analyses were performed on olive oils and on pizza topping mix samples after cooking to detect changes due to the applied cooking processing. RESULTS: The results revealed the best quality of a monovarietal olive oil (Ottobratica cv.) for their peculiar phenolic content related to the best oxidation stability after pizza's cooking, expressed as bioactive amounts and lower presence of undesired volatile compounds. CONCLUSIONS: The use of an extra virgin monovarietal olive oil, such as Ottobratica cv., in the topping of pizza is preferable to other oils, also EVOO, because of its higher quality, which is reflected in greater health and pleasant characteristics from a sensorial point of view.

Functionalization of a Vegan Mayonnaise with High Value Ingredient Derived from the Agro-Industrial Sector.

This work aimed to evaluate the antioxidant effect determined by the addition of phenolic extract on the oxidative stability and quality of vegan mayonnaise. Two different antioxidant extracts containing 100 mg L-1 of hydroxytyrosol and obtained by olive mill wastewater were used in the preparation. After preliminary studies, already evaluated in other works, on hydrophilic and lipophilic food matrices, the results of this study could contribute to understanding the effects of the enrichment on emulsified food systems with phenolic extracts. The functionalized mayonnaise samples were monitored up to 45 days of storage at 10 °C in comparison with a control sample for microbiological, physicochemical, antioxidant, sensory properties and for oxidative stability. The results achieved through this work showed the efficacy of the use of phenolic extract as ingredients for its positive effect on chemical properties of mayonnaise. The adding extracts lead to the increase of oxidative stability with an induction period higher (about 24 h) than the control sample (about 12 h).

Functionalized Biscuits with Bioactive Ingredients Obtained by Citrus Lemon Pomace.

In this study, functionalized biscuits were prepared through the enrichment of dough with lemon peel and natural antioxidants extracted from lemon pomace. Lemon pomace extract (LPE) was analyzed for total phenolic content before addition, and then a known concentration of 50 mg kg-1 was used for the formulation of enriched biscuits. Three different biscuit samples were compared to a control biscuit, without the addition of functional ingredients. The main physicochemical, microbiological, and sensory aspects of doughs and biscuits enriched with LPE were investigated. The enriched biscuits showed higher phenolic content and antioxidant activity than the control one and a longer induction period (IP), which means that the enriched products had a higher intrinsic resistance to lipid oxidation, thanks to the antioxidant effect exerted by the added fresh lemon peel and the LPE. Furthermore, from a sensorial point of view, they showed suitable acceptability, in terms of appearance, flavor, and aromatic attributes. Thus, results indicated that the incorporation of lemon processing by-products allowed the production of functional enriched biscuits with improved antioxidant properties.

Characterization of Olive Oils Obtained from Minor Accessions in Calabria (Southern Italy).

The valorization of minor accessions of olive is potentially a good way to improve the qualitative production of a specific territory. Olive oils of four minor accessions (Ciciarello, Tonda di Filogaso, and Ottobratica Calipa and Ottobratica Cannavà clones) produced in the same area of the Calabria region were characterized for the principal qualitative analyses at two drupe harvesting periods (October and November). Good quality in terms of free acidity, peroxides, spectrophotometric indexes, and fatty acid composition was observed in olive oils produced at both drupe harvesting times, with the exception of those of Tonda di Filogaso, which showed a free acidity level over the legal limit for extra virgin olive oil in the second harvesting time. All of the olive oils possessed at both production periods averagely abundant total polyphenols (460-778 mg/kg) and tocopherols (224-595 mg/kg), and the amounts changed in the experimental years for expected different environmental variations. Ottobratica Cannavà and Ottobratica Calipa clones showed some peculiar qualitative characteristics (free acidity, peroxides, fatty acid composition, and total polyphenols), distancing themselves from the principal variety of reference, Ottobratica.

Physical and Thermal Evaluation of Olive Oils from Minor Italian Cultivars.

Authentication of extra virgin olive oils is a key strategy for their valorization and a way to preserve olive biodiversity. Physical and thermal analysis have been proposed in this study as fast and green techniques to reach this goal. Thirteen extra virgin olive oils (EVOOs) obtained from minor olive cultivars, harvested at three different ripening stages, in four Italian regions (Abruzzo, Apulia, Sardinia, and Calabria) have been studied. Thermal properties, viscosity and color, as influenced by fatty acid composition and chlorophyll content, have been investigated. The thermal curves of EVOOs, obtained by differential scanning calorimetry, were mostly influenced by the oleic acid content: a direct correlation with the cooling and heating enthalpy and an indirect correlation with the cooling transition range were observed. The minor fatty acids, and particularly arachidic acid, showed an influence, mostly on the heating thermograms. Viscosity and color showed respectively a correlation with fatty acids composition and chlorophyll content, however they didn't result able to discriminate between the samples. Thanks to the principal component analysis, the most influencing thermal parameters and fatty acids were used to cluster the samples, based on their botanical and geographical origin, resulting instead the harvesting time a less influential variable.

Antioxidant Properties of Olive Mill Wastewater Polyphenolic Extracts on Human Endothelial and Vascular Smooth Muscle Cells.

This work aims to analyze the chemical and biological evaluation of two extracts obtained by olive mill wastewater (OMW), an olive oil processing byproduct. The exploitation of OMW is becoming an important aspect of development of the sustainable olive oil industry. Here we chemically and biologically evaluated one liquid (L) and one solid (S) extract obtained by liquid-liquid extraction followed by acidic hydrolysis (LLAC). Chemical characterization of the two extracts indicated that S has higher phenol content than L. Hydroxytyrosol and tyrosol were the more abundant phenols in both OMW extracts, with hydroxytyrosol significantly higher in S as compared to L. Both extracts failed to induce cell death when challenged with endothelial cells and vascular smooth muscle cells in cell viability experiments. On the contrary, the higher extract dosages employed significantly affected cell metabolic activity, as indicated by the MTT tests. Their ability to counteract H2O2-induced oxidative stress and cell death was assessed to investigate potential antioxidant activities of the extracts. Fluorescence measurements obtained with the reactive oxygen species (ROS) probe H2DCF-DA indicated strong antioxidant activity of the two OMW extracts in both cell models, as indicated by the inhibition of H2O2-induced ROS generation and the counteraction of the oxidative-induced cell death. Our results indicate LLAC-obtained OMW extracts as a safe and useful source of valuable compounds harboring antioxidant activity.

Environmental Impact of Food Preparations Enriched with Phenolic Extracts from Olive Oil Mill Waste.

Reducing food waste as well as converting waste products into second-life products are global challenges to promote the circular economy business model. In this context, the aim of this study is to quantify the environmental impact of lab-scale food preparations enriched with phenolic extracts from olive oil mill waste, i.e., wastewater and olive leaves. Technological (oxidation induction time) and nutritional (total phenols content) parameters were considered to assess the environmental performance based on benefits deriving by adding the extracts in vegan mayonnaise, salad dressing, biscuits, and gluten-free breadsticks. Phenolic extraction, encapsulation, and addiction to the four food preparations were analyzed, and the input and output processes were identified in order to apply the life cycle assessment to quantify the potential environmental impact of the system analyzed. Extraction and encapsulation processes characterized by low production yields, energy-intensive and complex operations, and the partial use of chemical reagents have a non-negligible environmental impact contribution on the food preparation, ranging from 0.71% to 73.51%. Considering technological and nutritional aspects, the extraction/encapsulation process contributions tend to cancel out. Impacts could be reduced approaching to a scale-up process.