Postharvest Management of Fruits and Vegetables

All articles in the presented collection are high-quality examples of both basic and applied research. The publications collectively refer to apples, bananas, cherries, kiwi fruit, mango, grapes, green bean pods, pomegranates, sweet pepper, sweet potato tubers and tomato and are aimed at improving the postharvest quality and storage extension of fresh produce. The experimental works include the following postharvest treatments: 1-methylcycloprpene, methyl jasmonate, immersion in edible coatings (aloe, chitosan, plant extracts, nanoemulsions, ethanol, ascorbic acid and essential oils solutions), heat treatments, packaging, innovative packaging materials, low temperature, low O2 and high CO2 modified atmosphere, and non-destructible technique development to measure soluble solids with infra- and near infra-red spectroscopy. Preharvest treatments were also included, such as chitosan application, fruit kept on the vine, and cultivation under far-red light. Quality assessment was dependent on species, treatment and storage conditions in each case and included evaluation of color, bruising, water loss, organoleptic estimation and texture changes in addition to changes in the concentrations of sugars, organic acids, amino acids, fatty acids, carotenoids, tocopherols, phytosterols, phenolic compounds and aroma volatiles. Gene transcription related to ethylene biosynthesis, modification of cell wall components, synthesis of aroma compounds and lipid metabolism were also the focus of some of the articles

Development of new analytical methods and application of chemometric tools in flavour research

In food science, there are several ways of defining quality, and perhaps there is no single universal definition that adequately satisfies all situations; in general terms, quality is defined as “the combination of attributes or characteristics of a product that have significance in determining the degree of acceptability of that product by the consumer”. The aim of this Thesis lies mostly on food quality field: indeed, one of the most important criteria for consumer acceptance of food is flavour. Due to the increasing demand of high quality and enjoyable foods, the need for methodologies enabling a better understanding of flavour has arisen: chemical analysis is a valuable way of studying volatile composition of different food matrices, and very sophisticated instrumentations are available nowadays, but almost always there is the need of clean-up/concentration steps before such analysis. Moreover, when volatile compounds are present in traces (ppb or even ppt), their detection and identification require the development of analytical tools which can tackle these difficult tasks: in the past, they were largely detected with insufficient performances or even undetected, due to the inadequacies in old-fashioned analytical techniques. Hence, in this work novel, simple, rapid, and “environmental friendly” sample preparation methods were implemented, which coupled really well with Thermal Desorption – Gas Chromatography – Mass Spectrometry (TD-GC-MS), following also the Green Chemistry requirements. It was investigated the use of Stir Bar Sorptive Extraction (SBSE) technique, showing that it is extremely suited for troublesome analytical challenges such as isolation of volatile compounds from several food matrixes, including both processed (beverages, yogurts) and fresh foods (fruits and vegetables); the application of this technique was thus broaden in new complex matrices (e.g. yogurts). This sorptive sample preparation showed good performances for practical, real-life analytical problems, which cannot easily be solved by alternative and time-consuming approaches: it allows an effective extraction of volatiles in the trace range, and a rich aromatic profile may be pursued using optimized conditions. SBSE has proven to be a technique that can offer high and reproducible extraction recoveries for the complex matrices under study; it was also characterized by ease of use, good repeatability and robustness. In addition, Headspace Solid Phase Micro-Extraction (HSPME) was used for sampling volatile from the headspace of olive oil samples: the point is that enrichment for gaseous samples is more difficult; particularly the analysis of polar compounds is an analytical problem that cannot be addressed adequately by conventional techniques, i.e. distillation, dynamic headspace, etc. Using this other solventless extraction technique, a reliable analytical method for the determination of a broad range of volatiles in olive oil was developed. Then, looking also at volatile release, which is a complementary task for a better understanding of interactions among food components, volatiles and in-vivo behavior, a real-time instrumentation, Proton Transfer Reaction - Mass Spectrometry (PTR-MS), was used to follow these rapid changing phenomena, without any need of sample preparation or calibration. The application of these analytical methods was then combined with the use of suitable chemometric techniques such as PCA (Principal Component Analysis), ASCA (Analysis of Variance combined to Simultaneous Component Analysis), MIXTURE DESIGN MODELING, and PLSR (Partial Least Squares Regression). We truly think that nowadays chemometrics is unavoidable and of utmost importance, when scientists have to deal with multivariate datasets, and when robust “chemical-driven” modeling of complex phenomena is needed

Synthesis of new pyrazolium based tunable aryl alkyl ionic liquids and their use in removal of methylene blue from aqueous solution

In this study, two new pyrazolium based tunable aryl alkyl ionic liquids, 2-ethyl-1-(4-methylphenyl)-3,5- dimethylpyrazolium tetrafluoroborate (3a) and 1-(4-methylphenyl)-2-pentyl-3,5-dimethylpyrazolium tetrafluoroborate (3b), were synthesized via three-step reaction and characterized. The removal of methylene blue (MB) from aqueous solution has been investigated using the synthesized salts as an extractant and methylene chloride as a solvent. The obtained results show that MB was extracted from aqueous solution with high extraction efficiency up to 87 % at room temperature at the natural pH of MB solution. The influence of the alkyl chain length on the properties of the salts and their extraction efficiency of MB was investigated