Elettra Marone

Comparing image (fractal analysis) and electrochemical (impedance spectroscopy and electrolyte leakage) techniques for the assessment of the freezing tolerance in olive

Olive growth and productivity are limited by low temperatures mainly during winter, but sometimes also in spring and fall. The most effective way to avoid these damages in areas subjected to these climatic conditions is to select least susceptible varieties, but the choice of the right method to determine cold hardiness is extremely difficult. The aims of the work were (1) to assess LT50 (lethal temperature at which 50% of damage in plants subjected to low temperatures occurs) of some olive varieties in two seasons (summer and winter) and (2) to assess the reliability of different methods to evaluate cold hardiness. LT50 was determined on 21 different olive (Olea europaea L.) Italian varieties by leaf and shoot electrolyte leakage, shoot impedance spectroscopy and leaf color determination of fractal spectrum. All the experiments were conducted on non-acclimated and cold-acclimated plants. Our results showed that all the three methods were able to detect damages on olive plants after exposure to low temperatures, with leaves appearing more sensitive to cold stress than shoots. Among these methods, fractal analysis could be very useful in assessing cold hardiness of plants on the basis of visible injury, without sophisticated or expensive instruments and in a reliable and cost-effective way, using only a scanning device, a personal computer and dedicated freeware software.

Sometimes a Little Mango Goes a Long Way: a Rapid Approach to Assess How Different Shipping Systems Affect Fruit Commercial Quality

Mangoes are climacteric and highly perishable fruits and represent the most appreciated tropical fruits in the world for their special taste and aroma. Depending on the structure of the supply chain and on general environmental and technical factors, fruit picking may be anticipated or postponed within the frame time of fruit maturation stage. Hence, mangoes may be collected for long distance sea freight at the unripe green stage, while pre-ripened fruits, usually transported by air to shorten storage time, are harvested later and must be eaten within few days. In the present study, we assess the potential of an evaluation technique that combines conventional ripening measures with the new detection system of volatile compounds using the PTR-ToF-MS to obtain information on the fruit “eating” quality state. Fruits from the same mango cultivar and shipped from the same country with two alternative shipping systems were compared by analysing the evolution of their physicochemical characteristics and volatile organic compound (VOCs) profiles in time. By pooling the entire dataset together, it emerges that VOCs and physicochemical parameters can be used to separate the two types of transport and the two different ripening stages for the air-freighted fruits, while the sea-freighted fruits showed a rather static behaviour between the two sampling time. The two combined methods may provide a simple and fast tool to assess the presence of characters strongly attractive to mango consumers and in a broader context can be helpful in giving a better idea about the eating qualities of the commercialized products.

Dietary supplementation with dried olive pomace in dairy cows modifies the composition of fatty acids and the aromatic profile in milk and related cheese

This study aimed to evaluate the effect of dietary integration of dried olive pomace (DOP), a by-product of olive oil separation, on nutritional and aromatic properties of milk and cheese. Twenty dairy cows were divided into 2 groups that were balanced for milk yield, parity, and days in milk. The control group was fed a conventional diet (20 kg of dry matter/head per day), whereas the experimental group (EG) received the conventional diet supplemented with DOP as 10% of dry matter. During the trial, milk yield was recorded and the samples of milk, cheese, total mixed rations, and DOP were collected and analyzed to determine the chemical-nutritional composition and aromatic profile. Atherogenic and thrombogenic indices were calculated on the basis of the fatty acid (FA) profile of milk and cheese. Data were analyzed according to the mixed model for milk yield and chemical composition, including cows nested within treatment as a random effect, whereas the general linear model was used for the analysis of cheese parameters. Differences were assessed by Tukeys test. The EG diet had a lower content of palmitic, stearic, and linoleic acids and a higher level of oleic acid compared with the control. Dietary DOP integration did not affect milk yield and composition with the exception of protein content, which was greater in EG and significantly affected by diet and period. Instead, period was found to be significant for fat and casein in both groups. Dietary supplementation with DOP modified the FA profile of milk and cheese. There was a decrease in short- and medium-chain FA, but significance was achieved only for palmitic acid. The stearic, isomer trans of oleic (in particular vaccenic acid), oleic, and isomer trans of linoleic acids significantly increased. Monounsaturated FA increased in EG milk and cheese and saturated FA were significantly lower, whereas no difference was marked between the groups regarding level of polyunsaturated FA. Supplementation with DOP reduced atherogenic and thrombogenic indices and increased conjugated linoleic acid in both milk and cheese. The free fatty acids, ketones, lactones, esters, and phenylalanine catabolites were increased in raw milk, whereas only leucine metabolism was affected by diet in pasteurized milk cheese at both 1 and 30 d of ripening. The present results pointed out that DOP supplementation may improve the nutritional and nutraceutical properties and modify the aroma of milk and derived cheese.

Covering the different steps of the coffee processing: Can headspace VOC emissions be exploited to successfully distinguish between Arabica and Robusta?

This work was performed to evaluate the possible application of PTR-ToF-MS technique in distinguishing between Coffea arabica (Arabica) and Coffea canephora var. robusta (Robusta) commercial stocks in each step of the processing chain (green beans, roasted beans, ground coffee, brews). volatile organic compounds (VOC) spectra from coffee samples of 7 Arabica and 6 Robusta commercial stocks were recorded and submitted to multivariate statistical analysis. Results clearly showed that, in each stage of the coffee processing, the volatile composition of coffee is highly influenced by the species. Actually, with the exception of green beans, PTR-ToF-MS technique was able to correctly recognize Arabica and Robusta samples. Particularly, among 134 tentatively identified VOCs, some masses (16 for roasted coffee, 12 for ground coffee and 12 for brewed coffee) were found to significantly discriminate the two species. Therefore, headspace VOC analyses was showed to represent a valuable tool to distinguish between Arabica and Robusta.

Sensory, spectrometric (PTR–ToF–MS) and chemometric analyses to distinguish extra virgin from virgin olive oils

Olive oil samples were obtained from six cultivars grown in different environments, and graded by chemical analyses as extra virgin (EVOOs). These were evaluated for flavors and off-flavors, and relative VOCs spectrum as determined by PTR–ToF–MS. A hierarchical clustering of Panel test data separated olive oil in three groups, one including the samples with perceived off-flavor (VOOs), regardless of cultivar and environment. The Pearson’s correlation coefficients between the mass data from PTR–ToF–MS and the sensory characteristics perceived by the Panel test were determined. A mass-to-sensory attributes correlation index was calculated. A color-coded card was built up based on the intensities (ncps) of five selected protonated mass data that was able to distinguish EVOOs from VOOs olive oil samples.

Lipolytic volatile compounds in dairy products derived from cows fed with dried olive pomace

The study was aimed at evaluating the effects of dietary supplementation with dried olive pomace in dairy cows on the development of lipolytic volatile compounds in raw milk and cheese. Twenty dairy cows, homogeneous for milk yield, parity and days in milk, were randomly assigned to a basal diet (CON) and a conventional diet integrated with dried olive pomace (DOP) as 10% of dry matter. After 60 days of treatment, raw bulk milk of CON and DOP groups was sampled and used to produce cheese that was sampled at 1, 7 and 30 days of ripening. Volatile compounds were analyzed by the SPME-GC/MS technique. Dietary treatment influenced C6, C8, C10 and C12 free fatty acids, the short-chain ethyl and methyl esters, many of ketones and γ- and δ-lactones in raw milk. Cheese showed main differences between groups after 7 days of aging. Levels of methyl decanoate and ethyl esters of even fatty acids from C4 to C14, as well as 2-heptanone, 6-dodecen-γ-lactone, octanal and some C9 secondary lipolytic catabolites such as 8-nonen-2-one, 2-nonanone and 2-nonenal were higher in DOP cheese. The γ-dodecalactone, δ-octalactone, 2-octenal and 1-hexanol were higher in the experimental cheese at 30 days of ripening. DOP dietary integration in feeding operations of dairy cows may modify the evolution of volatile compounds derived from lipolysis in milk and cheese toward moldy and peach notes. A sensory evaluation of these changes will be necessary to understand the consumer acceptability that represents an important feedback to drive dairy industry choices.

Nashi or Williams pear fruits? Use of volatile organic compounds, physicochemical parameters, and sensory evaluation to understand the consumer’s preference

Ripen “ready-to-eat” fruits of “Williams” and of two Nashi cultivars (“Hosui” and “Ya Li”), present contemporarily on the stores, were evaluated by physicochemical parameters (shape, skin color, firmness, total soluble solids, titratable acidity), volatile organic compounds (VOCs) emission, measured with a proton transfer reaction-time of flight-mass spectrometer (PTR–ToF–MS), either on whole and cube fruits, and sensory evaluation (panel test and consumer’s liking). The data were analyzed by ANOVA, LSD test, hierarchical clustering, PLS-DA, and CCOA. The highest differences for the physicochemical parameters were observed between Williams and Nashi, as Williams differentiated for sugar content and Hosui for firmness. By VOCs spectral analyses, it was observed that whole and cube “Williams” fruits had the highest number and amount of compounds, followed by “Ya Li;” “Hosui” was characterized by a few signals with low intensities. Fruits of each cultivar showed specific VOCs that could be used as markers for discrimination purposes. In “Williams” pears, the presence and amount of defined masses resulted linked to fruitiness and aroma perceived by the consumer. The higher sugar content and the typical pear aroma perceived by the panelists, emitted by “Williams,” could have influenced the consumer’s liking. The tasters appreciated “Hosui” for firmness, and “Ya Li” for visual, even if they resulted lower in sugar and flavor intensity. In the opinion of the respondents to the consumer test, “Williams” resulted the most appreciated both for the average scores of the acceptability and as percentage of responses at a level >5 of a nine-point hedonic scale.