Antioxidant capacity, ascorbic acid, total phenols and carotenoids changes during harvest and after storage of Hayward kiwifruit

The influences of harvest time and storage on the quality indices and nutritional content of kiwifruit were evaluated. Antioxidant capacity, ascorbic acid, total phenol content, carotenoids, soluble solids content and flesh firmness were determined in kiwifruit gathered at two different time (T1: 17-11-2005 and T2: 24-11-2005) and stored at 0 °C, for 2 or 6 months (S1 and S2, respectively). At the end of the cool storage, fruits were maintained for a week at 25 °C (S1 + 7d and S2 + 7d). The flesh firmness was reduced at the end of cool storage and the soluble solids content significantly increased, for exception of fruits harvested at T2 and stored for 6 months at 0 °C and a week at ambient temperature (S2 + 7d). Some nutritional characteristics such as vitamin C and carotenoids were higher in fruits gathered at T1 but these parameters were strongly influenced by storage, with a general decrease at the end of the long cool storage (6 months). Differently, no influence of long storage was observed in the fruit collected at T2 time. The maintenance for a week at room temperature, after long cool storage, determined an improvement of nutritional characteristics of kiwifruits. In conclusion, fruits harvested at T2 seem to improve their quality after a long storage (6 months) because they reach nutritional values similar or higher than those recorded in fruits at the harvest time. In spite of these positive results, these fruits showed a reduction in organoleptic characteristics which could negatively influence the fruit marketing. The obtained results underline the important role of the pre- and post-harvest factors on the qualitative and nutritional characteristics of kiwifruits

Effects of green compost on soil biochemical characteristics and nutritive quality of leafy vegetables

The application of organic residues to soil is widely developed during last years. In particular, green compost represents a good amendant with a low environmental impact and it can improve the quality of fruits and vegetables through an increase of sugars and organic acids. This aspect is extremely important because the modern consumer puts more attention to the healthy and nutritional properties of food. The aim of this research was to evaluate the effects of green compost used as soil amendment on phenols and vitamin C content and on antioxidant capacity. So plants of Lactuca sativa var. acephala cultivar Red Salad Bowl and Spinacia oleracea cultivar Lorelay were grown on three soil treatments: a) 100% soil, b) 75% soil plus 25% compost c) 50% soil plus 50% compost. Results show that adding green compost to soil improves its fertility and the plant’s growth. However the healthy properties of spinach decrease in function of the compost concentration in soil

Effect of rootstocks and harvesting time on the nutritional quality of peel and flesh of peach fruits

The influence was evaluated of four rootstocks (Ishtara, Mr. S 2/5, GF 677 and Barrier 1) and of harvesting time (early, middle, late) on the quality characteristics and nutritional value (vitamin C, phenols, carotenoids, total antioxidant capacity) of 'Flavorcrest' peach. The better rootstocks were Mr. S 2/5 (low-vigour) and Barrier 1 (high-vigour). In particular, Flavorcrest fruit on Mr. S 2/5 and on Barrier 1 rootstocks had higher antioxidant capacities and also higher phytochemical content, although fruits on Mr. S 2/5 were less firm. Flesh firmness was best for fruits at mid-harvest (H2, 7 July 2006), whereas phytochemical contents were best at late harvest (H3, 13 July 2006), when, for all rootstocks, the best nutritional characteristics were also recorded. Total antioxidant capacity and phytochemical content were determined for the peel and flesh. The results show that removal of peel from peach results in a significant loss of total antioxidant capacity

Arabidopsis thaliana MYB75/PAP1 transcription factor induces anthocyanin production in transgenic tomato plants

Tomato (Solanum lycopersicum L.) cv. Micro-Tom plants were transformed with the Arabidopsis thaliana (L.) Heyhn. MYB75/PAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT 1) gene. This gene encodes for a well known transcription factor, which is involved in anthocyanin production and is modulated by light and sucrose. Transgenic tomato plants expressing AtMYB75 were characterised by a significantly higher anthocyanin production in leaves, stems, roots and flowers under normal growth conditions. Further, they also exhibited anthocyanins in fruits. Anthocyanin accumulation was not widespread but took place in specific groups of cells located in epidermal or cortical regions or in proximity of vascular bundles. In all the organs of the transgenic plants, where AtMYB75 overexpression was determined, a clear increase in the accumulation of DFR (DIHYDROFLAVONOL 4-REDUCTASE) transcript was also detected. The expression of the tomato MYB-gene ANT1 (ANTHOCYANIN1), which had previously been identified as a transcriptional endogenous regulator of anthocyanin biosynthesis, was not altered. The higher basal content of anthocyanins in the leaves of the transgenic plants could be further increased in the presence of high light conditions and contributed to mitigate photobleaching damages under high irradiance

Mechanical Unfolding of Acylphosphatase Studied by Single-Molecule Force Spectroscopy and MD Simulations

Single-molecule manipulation methods provide a powerful means to study protein transitions. Here we combined single-molecule force spectroscopy and steered molecular-dynamics simulations to study the mechanical properties and unfolding behavior of the small enzyme acylphosphatase (AcP). We find that mechanical unfolding of AcP occurs at relatively low forces in an all-or-none fashion and is decelerated in the presence of a ligand, as observed in solution measurements. The prominent energy barrier for the transition is separated from the native state by a distance that is unusually long for α/β proteins. Unfolding is initiated at the C-terminal strand (βT) that lies at one edge of the β-sheet of AcP, followed by unraveling of the strand located at the other. The central strand of the sheet and the two helices in the protein unfold last. Ligand binding counteracts unfolding by stabilizing contacts between an arginine residue (Arg-23) and the catalytic loop, as well as with βT of AcP, which renders the force-bearing units of the protein resistant to force. This stabilizing effect may also account for the decelerated unfolding of ligand-bound AcP in the absence of force