Silvana Nicola

Hydrodistillation and in situ microwave-generated hydrodistillation of fresh and dried mint leaves: a comparison study.

BACKGROUND Hydrodistillation (HD) has been used since ancient times for the extraction of essential oils (EO). Despite the intrinsic limitations of this technique, it remains the most common method both in the laboratory and on an industrial scale. The main drawbacks are the long extraction time involved and the risk of thermal degradation. Over the last decade, microwave-assisted extraction (MAE) and in situ microwave-generated hydrodistillation (MGH) have been shown to be the most promising techniques in improving plant extraction and hydrodistillation. RESULTS In this study we compare HD with MGH in the extraction of several mint species cultivated in Piedmont: Mentha spicata L. var. rubra, Mentha spicata L. var. viridis and Mentha piperita L. MGH requires either fresh plant or rehydrated material, it is extremely fast and allows a reduction in energy consumption and overall cost. All the EO have been analyzed by gas chromatography-mass spectrometry. A mechanism of microwave-generated essential oil extraction has been proposed to explain the differences in the composition of the oil obtained from this environmentally friendly technique. CONCLUSIONS The yields and composition percentages of the EO obtained by HD and in situ MGH of fresh and dried mint leaves lie in a relatively narrow range, although MGH is faster. MW polarization effects and the water solubility of the components influence extract composition.

Producing garden cress (Lepidium sativum L.) for the fresh-cut chain using a soilless culture system

SUMMARY A soilless culture system (SCS) can improve the quality of raw material at harvest and enhance post-harvest shelf-life in many fresh-cut vegetables. Fresh-cut produce has been targeted to satisfy the increasing demand for convenience products for modern society. Recently, there has been growing interest to introduce garden cress into the fresh-cut supply chain. A standardised growing system is required to obtain suitable fresh-cut raw material in terms of marketable stage, low nitrate content, and long shelf-life. Four experiments were carried out to investigate a floating SCS and post-harvest management to produce marketable garden cress and to preserve its freshness during shelf-life. Various total N levels (6, 8, 12, or 16 mM), NO3–-N:NH4+-N ratios (25:75, 50:50, 75:25, or 40:60) in the growing nutrient solution, storage temperatures (4°C, 8°C, or 16°C), and five polypropylene (PP) films used during shelf-life, were tested. The research showed that garden cress is suitable for production in a SCS and that this technique leads to greater commercial production than soil culture, reaching > 600 g m–2 in 14 d, and > 4,700 g m–2 in 34 d. Total N at 12 mM was too high to obtain leaves with an acceptable nitrate content (< 2,500 mg kg–1 FW). Polypropylene film and storage temperature significantly influenced the loss of FW during shelf-life; however, this loss was always below 2%. The optimal storage temperature to maintain freshness was 4°C, while the five PP films tested showed inconsistent results.

Dietary Supplementation of Oregano and Sage Dried Leaves on Performances and Meat Quality of Rabbits

The aim of this research was to evaluate the dietary supplementation 1% (w/w) of oregano and sage dried leaves on performances and meat quality of broiler rabbits. A feeding trial, which lasted 48 d, was carried out on 105 male Bianca Italiana rabbits randomly divided in seven groups and fed ad libitum. At the end of the trial ten animals per group were slaughtered and samples of dorsal muscle were taken in order to perform laboratory analysis. Mortality rate did not statistically differ between groups. Growth performances of animals fed diets supplemented with aromatic plants were higher (P<0.05) than those of animals of control group, whereas carcass parameters were not affected by treatments excepting for the slaughter weight that showed the same trend as growth performances. Meat quality traits, oxidative lipid stability and fatty acid profile were not influenced by aromatic plant supplementation. In conclusion, oregano and sage in form of dried leaves can be used in rabbit without adverse effects on performance, carcass characteristics and meat quality traits.

Postharvest management affects spearmint and calamint essential oils

BACKGROUND The objectives of this work were to evaluate the phytomass yield, essential oil (EO) content and EO yield of Mentha spicata L. var. rubra, M. spicata L. var. viridis and Calamintha nepeta Savi in Piedmont (Italy), and to study how postharvest management (hydrodistillation of EO from fresh, dehumidified or oven-dried herbs) can affect the EO content and profile of the three species. RESULTS Mentha spicata L. var. rubra gave the greatest phytomass yield (1997 g m(-2)), which was statistically different from M. spicata L. var. viridis and C. nepeta. The highest EO yield was obtained from C. nepeta (3.75 g m(-2)), which was significantly different from the Mentha genus. Postharvest management significantly affected both the EO content and the EO profile of each species, with the dehumidifying process leading to a significantly higher EO content than the oven-drying process. The EO profile was different not only from species to species but also because of the postharvest management. CONCLUSION The dehumidifying process is a relatively new postharvest technology that has shown positive results in terms of EO yield, and it can be applied to species which have a high EO value, after evaluation of the resulting EO profile.

Water and nutrients supply in horticultural crops grown in soilless culture: resources efficiency in dynamic and intensive systems

It is currently possible to exploit specialised and standardised growing techniques in a context in which both land and water are becoming scarce. Agronomic innovation and automation are being coupled to an increasing sensitivity towards environment protection and a reduction in input losses. Consequently, modern horticulture is shifting from traditional culture systems, in the open field, to protected cultivation and soilless culture systems (SCS). Protected cultivation and SCS allow the provision of water and nutrients to the plant root system to be controlled and regulated, thus favouring root oxygenation. The punctual and real crop needs are satisfied by the hydroponic nutrient solution (HNS) . SCS introduce both resource optimisation and a reduction in losses, and thus increase food security and profitability in modern dynamic and intensive systems. Some SCS require the use of substrates or substrate mixes that must be chemically stable and should prevent the release of elements that can interfere with the HNS composition, thus inducing both phytotoxicity and microbial contamination. An HNS should be formulated using microbiologically safe water, and calibrating the macro-, meso- and micronutrients on the basis of the chemical composition of the water. However, it is also necessary to consider the interactions that occur in an HNS formulation between the individual elements that can affect plant growth, crop yield and injury susceptibility. Indicators, such as pH, electrical conductivity, oxygen content and temperature, should be checked periodically. The HNS supply period per day, volume per unit area or per plant, and the number of events during the day should be determined and tailored for a proper plant production in SCS. The HNS supply, whether continuous or discontinuous, can be supplied directly to the root using sub-irrigation or nebulisation systems, or from the aerial part using drip irrigation or sprinkling systems. The water and nutrient supply in SCS can be organized either through open-cycle hydroponic systems, in which the plants are fed with a specifically prepared HNS, without recovering the drainage, or through closed-cycle hydroponic systems, in which the drainage is collected, analysed, sanitised, integrated with the absorbed nutrients and re-inserted into the system. Each horticultural crop has its own specific water and nutrient supply needs that arise from specific physiological responses.

The Role of Research for a Sustainable Fertilization Management in Vegetables: Future Trends and Goals

Global vegetable production amounts to 1.13 billion tonnes from about 58 million of hectares; in the last decade global vegetable production increased at an average annual rate of around 3% although significant variability can be found in function of the region and the country. Beyond their monetary value, vegetables are important dietary sources of micronutrients so sustainable fertilization management should be aimed to produce healthy and environmentally sustainable vegetables by taking into considerations peculiarities of the vegetable production. Vegetables represent about 9% of the world market in fertilizer consumption (i.e. about 16 Mt, of which 9.1% of N, 9.4 of P2O5 and 10.0% of K2O). In the twenty-first century the research would be aimed at producing economical yields with reduced fertilizer inputs by the development and implementation of cropping systems, nutrient management approaches and crop varieties both showing higher nutrient/fertilizer use efficiency.