Flora V. Romeo

Antimicrobial Effect of Some Essential Oils

Abstract Commercially available oils of lavender (Lavandula angustifolia Mill.), lemon-balm (Melissa officinalis L.), juniper berry (Juniperus communis L.), lemon verbena (Lippia citriodora Kunth), rosemary (Rosmarinus officinalis L.) and cypress (Cupressus sempervirens L.) were evaluated for their antimicrobial activity. Analyses of the oils by GC-FID and GC/MS revealed that the major constituents of these oils were linalool (23.1%) and linalyl acetate (23.1%) in lavender, citronellal (23.8%) and geranial (11.6%) in lemon-balm, α-pinene (29.2%) in juniper berry, neral (36.2%) and geranial (41.9%) in lemon verbena, 1,8-cineole (24.4%) and camphor (17.1%) in rosemary, α-pinene (31.1%) and δ-3-carene (18.6%) in cypress oil. The antimicrobial activity of the essential oils was evaluated on survival and growth of some microorganisms potentially dangerous to the safety of foods (Escherichia coli, Staphylococcus aureus, Listeria innocua). The antimicrobial tests were carried out both in solid and in liquid media. E. coli was the most sensitive organism among the tested ones to the inhibition effect of the oils.

Phenolic trend and hygienic quality of green table olives fermented with Lactobacillus plantarum starter culture.

In this paper, four different olive cultivars from Southern Italy, Carolea, Cassanese, Nocellara del Belice, Nocellara Messinese table olives, produced according to traditional fermentation processes, were evaluated with the aim of assessing the effect of selected starter cultures on growth of bacterial population and on olive phenols during fermentation. Only Cassanese and Nocellara del Belice inoculated samples reached a safe pH value under 4.6 after 90 days while maintaining it until the end of storage. The most representative phenols in brine samples analysed by HPLC-MS/MS were hydroxytyrosol and verbascoside. Among the analysed phenols, only hydroxytyrosol, caffeic acid and ferulic acid always increased during fermentation, while the others increased up to 90-120 days and then decreased. The Principal Component Analysis (PCA) performed on pH and phenol values highlighted three clusters of olive cultivars. Throughout the brining period, lactic acid bacteria were always present while staphylococci and coliform bacteria disappeared after 30 and 90 days, respectively.

Effect of Some Essential Oils as Natural Food Preservatives on Commercial Grated Carrots

Abstract In the present work, the effects of lemon verbena (Lippia citriodora), cypress (Cupressus sempervirens) and lemon-balm (Melissa offcinalis) essential oils against the growth of three microorganisms (potentially dangerous to the safety of foods) were evaluated. The three oils were chosen and tested on grated carrots inoculated with bacteria and stored at 8°C until 8 days to simulate the market sale. The most resistant of the three strains against all the tested oils was Escherichia coli, while Listeria strain was the most easily influenced. An important interaction was revealed with the packaging type: oxygen diffusion greatly influenced the bacteria survival at the end of the experiment.

Shelf-life of Almond Pastry Cookies with Different Types of Packaging and Levels of Temperature

Almond pastries are typical cookies of the south of Italy. Introduction of new packaging for this kind of cookies requires shelf-life assessments. This study, related to different types of packaging under various storage conditions of time and temperature, identifies critical parameters, as color and texture, to track during storage studies and to extend the shelf-life. The cookies were packed in three different ways and stored at two different temperatures. The pastries were separately stored: (1) in polyvinylchloride film; (2) in aluminum foil (ALL); (3) with modified atmosphere (MAP) in plastic vessels sealed into a polyamide/ polyethylene film; and (4) in vessels without any polymeric film. The storage temperatures were 20 and 30 °C. Evolution of texture, water activity, dry matter and color was assessed. Texture was evaluated by a texture analyzer with a puncturing test. Indices for hardening were the area under the curve (N × mm) up to 10 mm of distance, and the maximum force (N) corresponding to the crust fracture. The best results were obtained with ALL packaging and MAP condition, and above all, in all the trials a temperature of 30 °C reduced the crust hardness.

Evaluation of a Pomegranate Peel Extract (PGE) as Alternative Mean to Control Olive Anthracnose

Olive anthracnose is caused by different species of Colletotrichum spp. and may be regarded as the most damaging disease of olive fruit worldwide, greatly affecting quality and quantity of the productions. A pomegranate peel extract (PGE) proved very effective in controlling the disease. The extract had a strong in vitro fungicidal activity against Colletotrichum acutatum sensu stricto, was very effective in both preventive and curative trials with artificially inoculated fruit, and induced resistance in treated olive tissues. In field trials, PGE was significantly more effective than copper, which is traditionally used to control the disease. The highest level of protection was achieved by applying the extract in the early ascending phase of the disease outbreaks because natural rots were completely inhibited with PGE at 12 g/liter and were reduced by 98.6 and by 93.0% on plants treated with PGE at 6 and 3 g/liter, respectively. Two treatments carried out 30 and 15 days before the expected epidemic outbreak reduced the incidence of the disease by 77.6, 57.0, and 51.8%, depending on the PGE concentration. The analysis of epiphytic populations showed a strong antimicrobial activity of PGE, which sharply reduced both fungal and bacterial populations. Because PGE was obtained from a natural matrix using safe chemicals and did not have any apparent phytotoxic effect on treated olive fruit, it may be regarded as a safe and effective natural antifungal preparation to control olive anthracnose and improve olive productions.

Nutritional Composition of Clementine (Citrus x clementina) Cultivars

Abstract Clementine fresh fruits have been always prized on the market for their typical agreeable physicochemical characteristics such as low acidity, good sugar level, and a well-balanced sugar to acid ratio. The oldest genotypes worldwide are considered to be ‘Fina’, or ‘Comune’, and ‘Monreal’ cultivars. The rapid spread of this crop in the last century has produced the isolation of several natural selections that are strictly different, compared with the ancient genotype in terms of ripening stage, peel color, vegetative habit, and fruit size. The selection of several early- and late-ripening mutants has led to an extension of the harvest period of the fresh fruit from September through October to mid-February. In the present work, the nutritional and antioxidant composition of traditional and modern clementine cultivars is critically reviewed with the final aim of identifying how nutrient and bioactive constituents vary with different clementine varieties.