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Summary Solid-phase microextraction (SPME) GC-MS was used to investigate the volatile organic compound (VOC) profile of fresh-cut ‘Big Top’ nectarine samples, stored in unsealed bags (AIR) or packed in active modified atmosphere (MAP) after 8 days of cold storage. Nectarine slices were also subjected to sensory and quality analysis after harvest and at the end of the storage. MAP preserved the overall quality, the appearance and the olfactory properties of nectarine slices during storage, while AIR samples showed symptoms of dehydration and browning. Sixty VOCs were identified in total in the headspace of the fresh nectarines and cold-stored fruit slices samples. Principal component analysis performed on VOCs allowed to differentiate fresh nectarines from cold-stored samples, with lactones and terpenes mainly related to fresh samples, and ester compounds positively correlated to AIR or MAP samples. Partial least square regression models allowed to identify a pool of VOC predictors of olfactory sensory descriptors.

Introduction: The Quality Level (QL) of table grape is defined through sensory evaluation of the its overall appearance by a five-point rating scale (from 5: excellent to 1: extremely poor). Since this evaluation is dependent on subjective judgments, the aim of this work was to develop methods based on MS-eNose and 1H NMR data for an objective QL assessment of two table grape cultivars, i.e. Vittoria and Italia. Methods: Table grape bunches were stored at 5 and 10 °C and sampled after a number of days needed to reach each QL. Berries were homogenized, centrifuged and the supernatant was analyzed by HS-SPME MS-eNose and 1H NMR. LDA and PLS-DA were applied on data to discriminate samples based on the five QLs (five class discrimination) and on their marketability/non-marketability (two class discrimination). Results: The model performances were expressed in terms of the prediction ability calculated by V-fold cross-validation procedure (CV=20%). For both cultivar, NMR model average prediction abilities ranged from 92 to 93%, and from 76 to 79%, in the two and five class discrimination, respectively. Better results were obtained in case of the MS-eNose models with mean prediction abilities ranged from 98 to 100% (two class discrimination), and from 86 to 100% (five class discrimination). In particular, the best prediction abilities of 100% were obtained in case of cv. Vittoria for MS-eNose PCA-LDA in both discriminations (two and five class discriminations) and for MS-eNose PLS-DA in the two class discimination. Conclusions: Taking into account the results obtained, both analytical technologies adopted herein could be used as valid and rapid tools for the table grape quality evaluation. In details, although NMR data can provides additional information on the identification of quality marker metabolites MS-eNose predictive models showed better performances in both types of discriminations.

Artichoke is classified as highly perishable product due to its high respiration rate that limits its shelf-life. Moreover, processing artichokes as a fresh-cut produce require washing, trimming and cutting operations that increase respiration rate, accelerate senescence and enzymatic browning, causing undesirable changes in the sensory, nutritional and health promoting properties. The use of post-harvest technologies can be a valid approach to preserve the quality and extend the shelf-life of this perishable product. Hence, the aim of this research was to evaluate the effect of a short-term treatment (48 h at 0°C) with different concentrations of high CO2 (CO2-10%, CO2-20%, CO2-30%, CO2-40% or AIR) in modified atmosphere (MA) on quality parameters and on Volatile Organic Compounds (VOCs) profile of fresh-cut artichokes. Samples were kept at 0°C for 48 h applying MA, then stored at 5°C in air and analyzed after 1, 4 and 7 days. The effect of different short-term CO2 treatments, storage time and their interaction on quality parameters was tested by a multifactor ANOVA and LSD Multiple Range Test. High CO2 short-term treatment until 30% reduced respiration rate, browning index, preserving the total phenol content and antioxidant activity at the level of untreated samples. The application of CO2 concentration around 40% might cause a fermentative metabolism. VOC profile study was performed by HS-SPME/GC-MS analysis, identifying 99 compounds. The VOC peak areas were used for Principal Component Analysis, showing that CO2-10% was the best treatment to preserve the volatile profile of the fresh samples, characterized by terpenes, alcohols, esters, aldehydes, hydrocarbon and heterocyclic compounds, while CO2-40% resulted associated to fermentative compounds mainly esters. In conclusion, the exposure of fresh-cut artichokes for 48 h at 0 °C at CO2-10% might be a promising postharvest treatment useful to preserve their quality and volatile profile during storage at 5 °C for 7 days.

REPORT DI RICERCA RELATIVO AL SECONDO ANNO DI ATTIVITA' E RISULTATI RAGGIUNTI NEL CORSO DELL'INTERO PROGETTO

Messa a punto di una SCALA SOGGETTIVA di valutazione della commerciabilità dei funghi freschi, corredata di immagini e di una breve descrizione dei parametri di qualità relativi al campione allo stato FRESCO, al LIMITE DELLA COMMERCIABILITÀ e NON COMMERCIABILE. Individuazione del PACKAGING OTTIMALE per il confezionamento di funghi freschi cardoncelli e definizione della shelf life.

Baby lettuce leaves are generally produced for the unwashed ready-to-eat market. The aim of this research was to predict sensory and microbiological aspects of this product based on physicochemical properties during storage at 4 and 10°C. Products were analysed at sampling times chosen on the basis of five sensory visual quality (VQ) levels. Samples scoring VQ5 and VQ4 were considered acceptable (Ac), whereas the remaining scores were defined as unacceptable (UAc). Each VQ level was then characterized for physico-chemical (colour, ammonium, antioxidant activity, electrolytic leakage, phenols, chlorophyll, respiratory activity) and microbiological (total viable count, Pseudomonas spp., Enterobacteriaceae, lactic acid bacteria, yeast and moulds) parameters. UAc samples also proved unsatisfactory from a microbiological point of view (total viable count >=107 CFU g-1). Partial least squares (PLS) regression analysis allowed us to identify colour change (?E*) and total chlorophyll (TC) as suitable variables to predict the microbial load (TVC) associated with each sensory VQ level. The model obtained showed R2CV=0.94, RMSECV=0.41 and a relative error of 5.61%. In conclusion, the use of these parameters as quality indicators could be a new strategy for discriminating green leafy vegetables into acceptable or unacceptable products.

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Baby lettuce leaves have recently been developed for the unwashed fresh-cut and ready-to-eat markets. The aim of this research was to characterize this product by sensory, physicochemical and microbiological analyses performed during storage at 4 and 10°C. Products were analysed at sampling times chosen on the basis of 5 sensory visual quality (VQ) levels. Samples scoring VQ5 and VQ4 were considered acceptable (Ac), whereas the remaining scores were defined as unacceptable (UAc). Each VQ level was then characterized for physicochemical (colour, ammonia, antioxidant activity, electrolytic leakage, phenols, chlorophyll, respiratory activity) and microbiological (total viable count, Pseudomonas spp, Enterobacteriaceae, lactic acid bacteria, yeast and moulds) parameters. UAc samples also proved unsatisfactory from a microbiological point of view (total viable count >=107 CFU/g). Partial Least Square (PLS) regression analysis allowed to identify colour change (?E*) and total chlorophyll (TC) as X-variables to predict the microbial load (TVC) (Y-variable) associated with each sensory VQ level. The model obtained showed R2CV=0.94, RMSECV=0.41 and a relative error of 5.61%. In conclusion, the use of these parameters as quality indicators could be a new strategy for discriminating green leafy vegetables into acceptable or unacceptable products.

Low oxygen controlled atmosphere was reported to be useful for fresh-cut broccoli raab cold storage in maintaining freshness and qualitative traits, whereas excessive accumulation of CO2 (10-15%) should be avoided. Starting from these finding the aim of this work was to individuate the proper modified atmosphere packaging (MAP) for fresh-cut broccoli raab in order to reach at the equilibrium the target atmosphere composition with low oxygen (3%) during cold storage. Broccoli raabs harvested from a commercial farm, were selected for defects and were cut from the stalks, obtaining the ready-to-use product. After washing the product was packaged in plastic trays sealed in bags of different plastic materials. Two commercially available polymeric coupled films (polypropylene/polyethylene terephthalate, PP/PET, and polypropylene/polyamide, PP/PA microperforated, MF), were used as packaging materials with or without the inclusion of a CO2 absorbers (used in 5-g sachets). For each packaging condition a passive (P-MAP) and an active atmosphere with 5% O2 in nitrogen (A-MAP) were used. Unpackaged samples were used as control and stored with all packages at 5 °C. Initially, and after 3 and 8 days samples were taken and quality attributes (overall appearance, odor, color analysis and weight loss) were evaluated. Gas concentrations (O2 and CO2) inside packages were also monitored. Among the packaging treatments tested the combination using PP/PA in A-MAP with the use of CO2 absorbing sachets reached equilibrium condition very close to optimal for broccoli raab. Fresh-cut broccoli raab stored in this condition for 8 days showed negligible reduction of appearance and odor scores, compared to the fresh samples resulting significantly higher than for the samples stored in all other packaging combinations.

Male zucchini flowers (Cucurbita pepo L.) are greatly appreciated by consumers although, due to their high perishability, they are destined only to local markets. The effects of four different atmosphere compositions (air, 3% O2 in nitrogen, 3% O2 + 10% CO2 in air, and 10% CO2 in air) on quality attributes of fresh male zucchini flowers (color, weight loss, respiration, fermentative volatiles, and vitamin C) were studied. Storage in controlled atmosphere significantly (P

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