Eristanna Palazzolo

Tetragonia tetragonioides, or New Zealand spinach, is a widespread halophyte native to eastern Asia, Australia, and New Zealand, and naturalized in some Mediterranean regions. This underutilized vegetable is consumed for its leaves, raw or cooked. For the first time, we investigated the feasibility of using whole baby plants (including stems and leaves) as raw material for ready-to-eat (RTE) vegetable production. Our study assessed Tetragonia’s suitability for hydroponic cultivation over two cycles (autumn–winter and spring). We investigated the impact of increasing nutrient rates (only water, half-strength, and full-strength nutrient solutions) and plant densities (365, 497, and 615 plants m⁻² in the first trial and 615 and 947 plants m⁻² in the second) on baby plant production. We also analyzed the plants’ morphological and biochemical characteristics, and their viability for cold storage (21 days at 4 °C) as a minimally processed product. Tetragonia adapted well to hydroponic cultivation across both growing periods. Nevertheless, climatic conditions, plant density, and nutrient supply significantly influenced plant growth, yield, nutritional quality, and post-harvest storage. The highest plant density combined with the full-strength nutrient solution resulted in the highest yield, especially during spring (1.8 kg m⁻²), and favorable nutritional characteristics (β-carotene, Vitamin C, Fe, Cu, Mn, and Zn). Furthermore, Tetragonia baby plants proved suitable for minimal processing, maintaining good quality retention for a minimum of 14 days, thus resulting in a viable option for the RTE vegetable market.

The demand for water for civil and industrial use is diminishing the availability of such a valuable environmental resource for agricultural purposes. Thus, for the next generation, it is imperative to find alternative water sources for crop irrigation. The citrus agroindustry utilizes a large amount of water for processing fruit (e.g., essential oil extraction, fruit washing). Wastewaters produced by citrus industry (CWWs) are rich in organic matter and mineral nutrients, thus making them potentially usable for crop irrigation. Conversely, due to their high content of organic acids and low pH, they may increase the availability of soluble metals, in the form of both plant nutrients and contaminants. The aim of this study was to evaluate the effect of CWWs on the dynamics of soil water-soluble metals and pH. To this end, CWWs from the processing of lemons, oranges, and tangerines at three different doses were used. CWWs were analyzed to investigate type and amount of organic acids. Soil water-soluble metals (Na, Mg, Al, K, Ca, Fe, Co, Ni, Cu, Zn, and Cd) and pH were determined at days 1, 3, 7, 21, and 28 after the addition of CWWs. Citric, ascorbic, oxalic, tartaric, acetic, and malic acids were found in CWWs, with citric acid being two orders of magnitude more concentrated than the other acids. After the addition of CWWs, soil pH promptly decreased from 7.2 to at least 5.3 depending on the type and concentration of CWWs. Concurrently, the concentration of almost all investigated metals sharply increased within 7 days after the addition of CWWs. Then, it decreased, reaching values similar to that of the control. The increase in metals availability as a consequence of pH decrease was ascribed to different causes: the exchange reaction between H⁺ and cations adsorbed onto colloid surfaces, the addition of organic matter by CWWs that stimulated microbial activity, and the quantity and type of organic acids added via CWWs. In conclusion, the obtained results suggest that the use of citrus wastewater for irrigation purposes could be a valid solution, with them being rich in plant nutrients and easily mobilized elements such as Ca, Mg, K, and Na. Further research is needed to refine the understanding of the impact of CWWs in the long term and to develop targeted strategies for managing industrial wastewater in agriculture.

Background: Soils under organic farming systems exhibit better quality and higher biological activity than conventional systems. Manure addition, especially coupled with reduced or no tillage, significantly enhances microbial biomass and activity by improving soil physical properties and providing carbon (C) and nitrogen (N) sources. While several studies have examined the effects of transitioning from conventional to organic farming on soil chemistry and biochemistry, limited research has explored the influence of land use variations on soil fertility within long‐term organic farming systems.Aims: Therefore, the aim of this study was to assess how three different land uses—pasture, vegetable crops, and orchard—affected soil fertility under a long‐term organic farming system.Methods: Soil samples were collected from the 0 to 15 cm layer of plots used for pasture, vegetable crops and orchard, being the latter cover cropped with legumes, and analyzed to determine chemical and biochemical soil parameters.Results: Contrary to expectations, high land use intensity (vegetable crops and orchard soils) resulted in increased soil organic C and total N, compared to low intensity (pasture). Such an increase was ascribed to farmyard manure addition that counteracted the negative impact of tillage. Consequently, microbial biomass C and activity also increased. The greatest availability of organic substrates favored bacteria, particularly gram‐positive strains, shaping the microbial community. However, despite changes of microbial biomass and of the main microbial groups, microbial activity was only slightly affected, suggesting high functional redundancy of microorganisms in long‐term organic farming soil.Conclusions: Results suggested that if land use intensification provides for organic supply, its negative impact on soil fertility may be mitigated.

The pericarp browning and postharvest microbiological decay of litchi fruit (Litchi chinensis Sonn cv Kwai Mai) significantly reduce its commercial potential in the fresh market. In this study, different combinations of modified atmosphere packaging (MAP) were applied at 5 ± 1 °C based on the use of natural gases that are innocuous to human health and an alternative to commercially adopted sulfur dioxide (SO₂) treatment. The results showed that control fruits, after 6 days of storage, begin to show the first symptoms of decay, revealed by the appearance of lesions and microbial infections determined by total mesophilic microorganisms and molds. This is not the case in the MAP-treated fruits and the MAP 3-treated (5% O₂ + 20% CO₂ + 75% N₂) fruits that show the best results. The control fruits, moreover, turned completely brown by the end of the storage period. The MAP 3 treatment was the most effective in preventing browning and the loss of the red pericarp color and vitamin content and in maintaining acceptable SSC/TA levels and flavor. In addition, a microbiological analysis revealed that all the MAP-treated litchi fruits did not harbor undesirable microorganisms during the entire cold storage period. In conclusion, the MAP 3 conditions delayed pericarp browning and maintained the better organoleptic quality of litchi fruits.

Tomato fruits defined as “golden” refer to a food product harvested at an incomplete ripening stage with respect to red tomatoes at full maturation. The aim of this study is to explore the putative influence of “golden tomato” (GT) on Metabolic Syndrome (MetS), especially focusing on the effects on redox homeostasis. Firstly, the differential chemical properties of the GT food matrix were characterized in terms of phytonutrient composition and antioxidant capacities with respect to red tomato (RT). Later, we assessed the biochemical, nutraceutical and eventually disease-modifying potential of GT in vivo in the high-fat-diet rat model of MetS. Our data revealed that GT oral supplementation is able to counterbalance MetS-induced biometric and metabolic modifications. Noteworthy is that this nutritional supplementation proved to reduce plasma oxidant status and improve the endogenous antioxidant barriers, assessed by strong systemic biomarkers. Furthermore, consistently with the reduction of hepatic reactive oxygen and nitrogen species (RONS) levels, treatment with GT markedly reduced the HFD-induced increase in hepatic lipid peroxidation and hepatic steatosis. This research elucidates the importance of food supplementation with GT in the prevention and management of MetS.

The citrus industry produces a large number of sludges as a consequence of citrus wastewater treatment. The correct disposal of citrus sewage sludges (CSSs) has been attempted using anaerobic digestion, aerobic digestion, and lime stabilization. However, since CSSs hold nitrogen, phosphorus, and other macronutrients required by crops, in line with the circular economy principles, they could be utilized for agricultural purposes, such as organic fertilizer. The aim of this study was to assess the effect of CSSs supplied at different doses on soil fertility and lettuce performance. To this end, a pot experiment was established. The soil was amended with CSSs at three different concentrations (2.5, 5, 10 t ha⁻¹). After 46 days of lettuce growth, the experiment was stopped, and soils and plants were analyzed. Soil amended with CSSs showed an increase in total organic C ranging from 7% to 11%. Additionally, available P increased but only at the highest CSS dose. The addition of CSSs affected the biochemical properties of soil, but a univocal trend related to the number of CSSs applied was not found. Microbial biomass C increased only with the highest dose of CSS applied, while the metabolic quotient (qCO₂) decreased. Such a positive effect on soil fertility and soil microorganisms, in turn, lead to an increase in lettuce biomass. Moreover, results indicated that following CSS addition, lettuce crops adsorbed more N in leaves than in roots, whereas P, Ca, Mg, K, and Na showed an opposite pattern and increased more consistently in roots. In conclusion, amendment with CSSs enhances soil fertility by increasing, regardless of CSS dose, total organic C, and, at the highest dose, P availability and microbial biomass C. Such improvement in soil fertility, in turn, increases lettuce biomass production without affecting its quality, i.e., alteration of the (K + Na)/(Ca + Mg) ratio.

Weed control in urban and peri-urban orange orchards is challenging due to operational and legislative restrictions. Tillage, besides from negatively affecting soil fertility and microorganisms, is demanding for humans. On the other hand, herbicides are advised against due to the possibility to reach waterbodies from the soil surface. Therefore, in urban and peri-urban areas, instead of tillage and herbicides, mulching with black plastic geotextile fabric is often used. This study aimed at assessing the impact of long-term soil mulching with black plastic geotextile fabric on soil fertility, microbial community and yield of an orange orchard in comparison to conventional tillage. To this aim, four soil management systems were set up: rotary tillage for the last 15 years, mulching with black plastic geotextiles for the last 15 years, rotary tillage for 7 years followed by mulching for the last 8 years, mulching for 7 years followed by rotary tillage for the last 8 years. Soil samples were analyzed to determine the chemical and biochemical parameters related to soil fertility. In addition, the abundances of the main microbial groups were investigated. Mulching increased soil total organic C at least by 65%. The greater soil organic C in mulched soil in turn contributed to increase the cation exchange capacity (+62% on average) and microbial biomass C (+120% on average). Additionally, the microbial quotient exhibited higher values in mulched soils compared to tilled ones, suggesting a greater soil organic matter accessibility by soil microorganisms. Moreover, mulching favored fungi over bacteria, and Gram-positive bacteria over Gram-negative bacteria, thus contributing to the establishment of a microbial community more efficient in utilizing C sources. The latter result was confirmed by the lower values of the metabolic quotient in mulched soil compared to tilled one. Overall, the black plastic geotextile fabric improved chemical and biochemical soil fertility that, in turn, lead to a higher orange yield in mulched soil.

The aim of this study was to produce a fresh ovine pressed cheese within Pecorino “Primosale” typology with the addition of citrus essential oils (EOs). For this purpose, ewe’s pasteurized milk was added with EOs from the peel of lemons, oranges and tangerines. Seven cheese productions were performed at the pilot plant scale level, including one control production (CP) without the addition of EOs and six experimental productions obtained by the addition of two EO concentrations (100 and 200 µL/L) to milk. The acidification process was obtained by means of the starter cultures Lactococcus lactis CAG4 and PON36. All cheeses showed levels of lactic acid bacteria (LAB) around 10⁹ CFU/g, indicating that citrus EOs did not negatively influence the starter evolution. The addition of citrus EOs did not determine significant variations for dry matter, fat and protein percentages but increased the antioxidant capacity of all the experimental cheeses of about 50% in comparison to the control trial. The citrus EOs impacted cheese VOCs, especially for terpene class (limonene, β-pinene, myrcene, carene, linalool and α-terpineol). The sensory evaluation showed that cheeses enriched with 100 µL/L of citrus EOs were mostly appreciated by the panelists.

Loquat fruits, highly valued by consumers for their characteristic aroma and pleasant taste, have a short post-harvest life and are susceptible to mechanical damage, loss of firmness, and initial organoleptic characteristics. The aim of this work was to develop a drying method suitable for storing loquat fruits in polyamide/polyethylene (PA/PE) bags containing two gaseous mixtures (treatments): MAPN₂ (100% N₂) and MAPP (21% O₂ and 0.04% CO₂), at room temperature (20 ± 1 °C) for at least 2 months. The effects of these conditions on the physico-chemical, microbiological, proximate, and sensory properties of fruit stored over a 50-day time interval were studied. The results showed that convective tray dehydration treatment at 70° for 12 h had good drying efficiency for loquat slices. In addition, the MAPN₂ packaging limited the browning of the slices, keeping the microbial groups below the detection limits, with a clear positive effect on some minerals and vitamins, which were higher in concentration compared to the MAPP-packed samples. From an applicative point of view, the tray drying method for loquat fruits is useful on a small scale but could also be easily industrialized.