Sugar profiles as a promising tool in tracing differences between potato cultivation systems, botanical origin and climate conditions

Content and distribution of major and trace elements as a tool to assess the genotypes, harvesting time, and cultivation systems of potato

The effects of organic versus integral and conventional crop management on content and distribution of major and trace elements in different varieties of potato were investigated in a three year field trial. A set of 48 potato tubers of four varieties with different harvesting times, cultivated in three types of agricultural systems: conventional (C), integral (I), and organic (O) were characterized based on the composition of the elements of their bulk and peel. A total of 16 elements were quantified. In order to determine the source of variation among the types of production, parts of potato and varieties, multivariate analysis of variance (MANOVA) was conducted. The results indicate that Ca, Mg, and K may be considered as important indicators of the type of production, genotypes of potato, and harvesting time. Additionally, the analyses show that ten microelements are able to distinguish between production types and genotypes of potato.

Analysis of Structural and Functional Differences of Glucans Produced by the Natively Released Dextransucrase of Liquorilactobacillus hordei TMW 1.1822

The properties of the glucopolymer dextran are versatile and linked to its molecular size, structure, branching, and secondary structure. However, suited strategies to control and exploit the variable structures of dextrans are scarce. The aim of this study was to delineate structural and functional differences of dextrans, which were produced in buffers at different conditions using the native dextransucrase released by Liquorilactobacillus (L.) hordei TMW 1.1822. Rheological measurements revealed that dextran produced at pH 4.0 (MW = 1.1 * 108 Da) exhibited the properties of a viscoelastic fluid up to concentrations of 10% (w/v). By contrast, dextran produced at pH 5.5 (MW = 1.86 * 108 Da) was gel-forming already at 7.5% (w/v). As both dextrans exhibited comparable molecular structures, the molecular weight primarily influenced their rheological properties. The addition of maltose to the production assays caused the formation of the trisaccharide panose instead of dextran. Moreover, pre-cultures of L. hordei TMW 1.1822 grown without sucrose were substantial for recovery of higher dextran yields, since the cells stored the constitutively expressed dextransucrase intracellularly, until sucrose became available. These findings can be exploited for the controlled recovery of functionally diverse dextrans and oligosaccharides by the use of one dextransucrase type.

The Impact of Organic vs. Conventional Agricultural Practices on Selected Quality Features of Eight Potato Cultivars

An organic agricultural system based on natural methods and means of production is an alternative to intensive agriculture. The available research suggests that organic crops, in comparison to the conventional ones, are richer in phenolics and other antioxidants while containing less undesirable pesticide residues and nitrates. The aim of this study was to determine concentrations of polyphenols, lutein, vitamin C, and nitrates in eight potato cultivars (Mazur, Justa, Lawenda, Lech, Tacja, Laskana, Otolia, Magnolia) grown organically and conventionally in a controlled field experiment in Poland. Significant differences between potato tubers of the tested cultivars coming from organic and conventional production were identified for the majority of parameters. Higher concentrations of nitrates and lutein were found in conventional compared to the organic tubers, while organic potatoes were, on average, richer in phenolic compounds. Among the tested cultivars, Magnolia, Otolia, and Laskara were richest in vitamin C and phenolics. Otolia and Laskara also accumulated the highest levels of nitrates. If further confirmed, these observations might be of importance for the producers and consumers, who increasingly search for foods from sustainable and well-controlled agricultural systems.