High-rate J-testing of toughened polypropylene

2nonenoneF. MARTINATTI; T. RICCO'F., Martinatti; Ricco', Theoni

Agrimoniin the most important ellagitannin in human diet: elucidation of its identity in strawberry fruits and the influence of fruit ripening on its concentration

Of the most commonly consumed berries, strawberries (Fragaria ananassa Duch.) are the most popular choice with consumers, being eaten both fresh and frozen, as well as in different processed products. Although the composition of strawberry fruit has been extensively studied, especially for the most abundant phenolic compounds, agrimoniin has been only recently univocally identified as one of the most abundant phenolic compounds in the fruit (Vrhovsek et al. 2012). In this study agrimoniin was isolated in the fruit of Fragaria vesca and its structure fully characterized, reporting for the first time the full NMR assignments for this dimeric ellagitannin. Agrimoniin is a known bioactive compound, which has been used for treatment of diarrhea and haemorrhaging and reported to have antitumor properties. Its presence as the main ellagitannin in both F. vesca and Fragaria ananassa D. fruit is therefore noticeable. The establishment of a new HPLC protocol for the separation of the strawberry ellagitannins, and the isolation and characterisation of other ellagic acid derivatives, allowed us to produce an accurate quantification of the main ellagitannins and ellagic acid conjugates in 6 different varieties of strawberry and in 2 woodland strawberry at four different ripening stages from the green stage up to overripe fruit. Of fruit containing ellagitannins, strawberries are the most widely consumed, and agrimoniin is suggested to be one of the most widely present ellagitannins in the human diet. Agrimoniin, together with the other strawberry ellagitannins and ellagic acid derivatives characterised in this study, deserve further attention since they are expected to play an important, yet still largely unexplored, role in the beneficial health effects associated with the consumption of strawberries by humans

Texture profiling for strawberry fruit development and ripening

During the ongoing of strawberry ripening one of the most relevant changes is fruit softening which occurs very rapidly, causing the major loss during the short-term post-harvest storage, strongly affecting the commercial chain and the fruit economic value. Textural attributes vary significantly within strawberry cultivars and these are largely dependent by the genetic constitution as well as environmental and horticultural management. Fruit softening is usually associated with an extensive modification of pectin and hemicellulosic cell wall fractions which in turn is determined to a great extent by the action of cell wall-modifying enzymes, with particular regards to pectin methylesterase, polygalacturonase, endoglucanase, α-arabinofuranosidase, β-galactosidase, and β-xylosidase (Figueroa et al., 2010). To support future breeding programs aimed to improve strawberry fruit texture we have applied a texture analyzer TAXT plus in order to improve the phenotyping resolution, profiling the mechanical response of the samples during the compression phase. This advanced phenotyping technology was employed in this context in order to monitor the texture evolution during strawberry fruit development, ripening and post-harvest in three short day cultivars: Elsanta, Darselect and Candonga. In addition, this equipment was also exploit to dissects the fruit texture behaviour of 28 varieties, both junebearing and everbearing

QTL mapping for fruit quality traits in the cultivated octoploid strawberry (Fragaria x ananassa)

Fruit quality represents an essential factor driving consumers' appreciation and it is therefore one of the major target in ongoing breeding programmes for strawberry. Several phenotypic traits contribute in defining fruit quality in cultivated strawberry: chemical characteristics, fruit flavor and fruit texture. Among all the quality attributes of strawberry, fruit texture is gaining in the recent times more and more importance and interest. Fruit texture properties strongly determine the shelf life, frequency of harvest, postharvest deterioration, transportation and storage of the commercialized berries. Unfortunately, the genetic basis determining fruit texture characteristics in strawberries are still unknown and part of this lack of knowledge is depending on the elaborate physiological nature. Texture, indeed, can be described as a complex feature composed of mechanical properties relying on the modifications occurring in the cell wall during fruit softening and ripening. In order to decipher the genetic determinants of fruit quality traits in cultivated strawberry a QTL mapping analysis was performed on a octoploid strawberry segregating population including a 85 full-siblings F1 progeny from a cross between the varieties 'Darselect' and 'Monterey'. This population was previously genotyped (Sargent DJ et al, 2016) by using the Axiom® IStraw90® array for linkage map development. The population was phenotypically investigated during two years (2014-2015) and a third year is currently under evaluation. Fruit quality was investigated in homogeneous strawberries sampled at the ripening stage. Thus, berries chemical characteristics (total soluble solids, sugar concentration, pH and titratable acidity), and berry texture parameters defining the force displacement profile (maximum force, final force, area, maximum deformation, minimum deformation, maximum force strain, and gradient) have been measured for all the progeny individuals and parental genotypes. The QTLs study was performed by SIM and CIM analyses on the parental as well as the co-integrated maps. Some QTLs for fruit-quality traits were thus identified and in some cases they could be located on the same homoeologous groups found in previous studies. In particolar, regarding fruit texture parameters, QTLs for the maximum force, final force, area and gradient (elasticity module) were found co-localizing with already described QTLs as well as mapping in up to now unreported genomic positon. Ongoing work is focused on better characterizing the QTLs identified and to evaluate the GxE interactions and their stability across years, by checking an additional ripening season. These results underline the importance of a better dissection and definition of fruit texture and support the interest of traits association in different genetic backgrounds and utility in multiple breeding programmes