Ana L. Amaro

Multi-trait analysis of post-harvest storage in rocket salad (Diplotaxis tenuifolia) links sensorial, volatile and nutritional data.

Rocket salad (Diplotaxis tenuifolia; wild rocket) is an important component of ready to eat salads providing a distinct peppery flavour and containing nutritionally relevant compounds. Quality deteriorates during post-harvest, in relation to time and storage temperature amongst other factors. Volatile organic compounds (VOCs) are easily measurable from rocket leaves and may provide useful quality indicators for e.g. changes in isothiocyanates derived from nutritionally important glucosinolates. VOC profiles discriminated storage temperatures (0, 5 and 10°C) and times (over 14days). More specifically, concentrations of aldehydes and isothiocyanates decreased with time paralleling a fall in vitamin C and a reduction in sensorial quality at the two higher temperatures. Sulphur containing compounds rise at later time-points and at higher temperatures coincident with an increase in microbial titre, mirroring a further drop in sensorial quality thus indicating their contribution to off-odours.

Multitrait analysis of fresh-cut cantaloupe melon enables discrimination between storage times and temperatures and identifies potential markers for quality assessments

Fresh-cut cantaloupe melon is valued for its aroma but is highly perishable. Temperature of storage (typically 0-5°C) is critical for maintaining fresh-cut melon quality, but often reaches 10°C during transportation and in retail outlets. A comparison amongst 0, 5 and 10°C storage temperatures for fresh-cut melon over 14days reveals that storage at 0°C is optimal for avoiding increases in microbial load and loss of vitamin C especially at later time points. However, higher temperatures maintain better the balance of esters (acetate versus non-acetate) and phenolic content. The whole volatile organic compound (VOC) profile can be used to discriminate both time and temperature effects especially at earlier time points. Potential VOC markers for changes in vitamin C from day 0 to day 6 of storage (3-methyl butane nitrile) and temperature (limonene) are identified through a multi-trait analysis.

Biologically Active Compounds in Melon: Modulation by Preharvest, Post-harvest, and Processing Factors

Abstract Melon ( Cucumis melo L.) is a widely consumed fruit whose major biologically active compounds are the vitamins C, pro-vitamin A, and folic acid, the phenolic phytochemicals and the toxic cucurbitacins. Levels of biologically active compounds in melon vary widely and are affected by genotype and environmental conditions during production and post-harvest handling, with strong interactions between cultivar and environmental effects. Ascorbic acid levels are generally reduced by processing methods. β-Carotene concentration also varies widely with genotype and is affected by processing conditions. Phenolics are generally preserved during storage and processing of raw materials but can be enhanced by roasting. Cucurbitacin levels, although negligible in commercial cultivars, may become important in pharmacological or ethnobotanical applications.

Influence of Dairy Cattle Slurry Solid Fraction Compost Combined with Mineral Nitrogen Fertilizer on the Growth of Greenhouse Lettuce

Winter lettuce response to the application of composts from the solid fraction of dairy cattle slurry was assessed in combination with mineral nitrogen (N) fertilizer throughout a randomized block experiment under greenhouse conditions. Lettuce yield did not increase with mineral N fertilizer, possibly because the lettuce was preceded by a heavily fertilized tomato crop, and the amount of mineral N (114 kg ha−1) in the soil at the beginning of the experience was greater than the amount of N (64–89 kg ha−1) accumulated in the lettuce shoots of all of the treatments. In contrast, lettuce yield and N uptake increased with compost application, suggesting other benefits in addition to N availability resulting from its use as a soil amendment. Therefore, dairy cattle slurry solid fraction mature compost can be recommended for vegetable production, and mineral N recommendation is suggested to pursue previous soil mineral N analysis.