Effective ways of decreasing acrylamide content in potato crisps during processing

The aim of this work was to examine the effect of blanching or soaking in different acid solutions on the acrylamide content in potato crisps. Furthermore, the effects of a shorter frying time and a lower frying temperature combined with a postdrying were investigated. Soaking or blanching of potato slices in acidic solutions decreased the pH of potato juice and increased the extraction of amino acids and sugars. Potato crisps obtained after such pretreatments were characterized by lower acrylamide content. The most effective extraction of free amino acids and sugars as well as the largest decrease of acrylamide content (90%) in crisps was obtained when potato slices were soaked in acetic acid solution for 60 min at 20 degrees C. Shorter frying time followed by postdrying resulted in low-moisture potato crisps. Furthermore, the postdrying treatment gave a decreases in acrylamide content of approximately 70% when potato slices were fried at 185 degrees C and approximately 80% when potato slices were fried at 160 degrees C. Effective ways of decreasing acrylamide content in crisps production have been found. Crisps with low acrylamide content and good sensory quality can be obtained either by blanching in acetic acid as pretreatment or by a short frying followed by postdrying.     

Molecular cloning of Tulipa fosteriana rDNA and subsequent FISH analysis yields cytogenetic organization of 5S rDNA and 45S rDNA in T. gesneriana and T. fosteriana

In this study, Tulipa fosteriana was found to contain 45S rDNA repeat units of 9.7 and 9.5 kb, in which at least 7 types of 45S rDNAs were identified by restriction site analysis. For 5S rDNA, repeat units ranging from 364 bp to 396 bp were identified. The diploid cultivars (2n = 2x = 24) ‘Christmas Dream’ and ‘Queen of Night,’ representing the horticultural group T. gesneriana, and ‘Red Emperor’, belonging to T. fosteriana, were compared cytogenetically using cloned 5S and 45S rDNAs. Fluorescence in situ hybridization (FISH) analysis identified many rDNA sites located on each chromosome in the diploid genomes. For example, we identified 71 sites of 5S rDNA and 10 sites of 45S rDNA in ‘Red Emperor’. Additionally, FISH analyses enabled construction of karyotypes for these cultivars. Karyotype comparison of T. gesneriana cultivars showed conservation of repetitive rDNA unit positioning. A clear difference in chromosome size and signal pattern was observed between T. gesneriana and T. fosteriana cultivars. Here we demonstrate the unique nature of the highly repeated 5S rDNA units in these Tulipa species and the usefulness of FISH karyotyping with cloned 5S and 45S rDNAs to clearly distinguish between chromosomes from T. gesneriana and T. fosteriana. Hitoshi Mizuochi and Agnieszka Marasek contributed equally to this paper     

Unraveling the chemical composition of caramel

Caramel is one of mankind's best known dietary materials obtained from carbohydrates by heating. Much effort has been expended toward the chemical characterization of the components of caramel but impeded by a lack of suitable analytical techniques sufficiently powerful for providing insight into an extraordinarily complex material. This paper reports the characterization of caramel formed by heating from glucose, fructose, and saccharose using a conceptually novel combination of mass spectrometrical techniques. The analytical strategy employed uses high-resolution mass spectrometry (MS) followed by targeted liquid chromatography-tandem MS experiments. Caramel is composed from several thousand compounds formed by a small number of unselective and chemoselective reactions. Caramelization products include oligomers with up to six carbohydrate units formed through unselective glycosidic bond formation, dehydration products of oligomers losing up to a maximum of eight water molecules, hydration products of sugar oligomers, disproportionation products, and colored aromatic products.     

Phenolic compound profiles and antioxidant capacity of Persea americana Mill. peels and seeds of two varieties

Avocado processing by the food and cosmetic industries yields a considerable amount of phenolic-rich byproduct such as peels and seeds. Utilization of these byproducts would be favorable from an economic point of view. Methanolic (80%) extracts obtained from lyophilized ground peels and seeds of avocado (Persea americana Mill.) of the Hass and Shepard varieties were characterized for their phenolic compound profiles using the HPLC-PAD technique. The structures of the identified compounds were subsequently unambiguously confirmed by ESI-MS. Compositional analysis revealed that the extracts contained four polyphenolic classes: flavanol monomers, proanthocyanidins, hydroxycinnamic acids, and flavonol glycosides. The presence of 3-O-caffeoylquinic acid, 3-O-p-coumaroylquinic acid, and procyanidin A trimers was identified in seeds of both varieties. Intervarietal differences were apparent in the phenolic compound profiles of peels. Peels of the Shepard variety were devoid of (+)-catechin and procyanidin dimers, which were present in the peels of the Hass variety. Peels of both varieties contained 5-O-caffeoylquinic acid and quercetin derivatives. The differences in the phenolic profiles between varietals were also apparent in the different antioxidant activity of the extracts. The peel extracts had a higher total phenolic compound content and antioxidant activity when compared to the seed extracts. The highest TEAC and ORAC values were apparent in peels of the Haas variety in which they amounted to 0.16 and 0.47 mmol Trolox/g DW, respectively. No significant (p > 0.05) differences were apparent between the TEAC values of seeds of the two varieties but the ORAC values differed significantly (p < 0.05). Overall these findings indicate that both the seeds and peel of avocado can be utilized as a functional food ingredient or as an antioxidant additive.     

Efficient transplantation via antibody-based clearance of hematopoietic stem cell niches

Upon intravenous transplantation, hematopoietic stem cells (HSCs) can home to specialized niches, yet most HSCs fail to engraft unless recipients are subjected to toxic preconditioning. We provide evidence that, aside from immune barriers, donor HSC engraftment is restricted by occupancy of appropriate niches by host HSCs. Administration of ACK2, an antibody that blocks c-kit function, led to the transient removal of >98% of endogenous HSCs in immunodeficient mice. Subsequent transplantation of these mice with donor HSCs led to chimerism levels of up to 90%. Extrapolation of these methods to humans may enable mild but effective conditioning regimens for transplantation.     

Bright coherent ultrahigh harmonics in the keV x-ray regime from mid-infrared femtosecond lasers

High-harmonic generation (HHG) traditionally combines ~100 near-infrared laser photons to generate bright, phase-matched, extreme ultraviolet beams when the emission from many atoms adds constructively. Here, we show that by guiding a mid-infrared femtosecond laser in a high-pressure gas, ultrahigh harmonics can be generated, up to orders greater than 5000, that emerge as a bright supercontinuum that spans the entire electromagnetic spectrum from the ultraviolet to more than 1.6 kilo-electron volts, allowing, in principle, the generation of pulses as short as 2.5 attoseconds. The multiatmosphere gas pressures required for bright, phase-matched emission also support laser beam self-confinement, further enhancing the x-ray yield. Finally, the x-ray beam exhibits high spatial coherence, even though at high gas density the recolliding electrons responsible for HHG encounter other atoms during the emission process.     

Assessment of the impact of climate change on the latency period of leaf rust on triticale in Poland

ABSTRACT

Disease development in plants is strongly dependent on weather conditions, with temperature playing a particularly significant role by influencing latency period duration. Using two models describing the relationship between latency period and temperature, we performed simulations aimed at predicting changes in the latency period of leaf rust (Puccina recondita f. sp. tritici) on triticale in response to expected climate change. The simulations were based on meteorological data recorded in the period 1986–2005 at locations representing 16 provinces in Poland and based on values obtained after transformation of the observed data to reflect temperature changes under four scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) according to the giss_e2_r climate model. In all scenarios, the results for the two triticale cultivars studied, Witon (vulnerable to P. recondita) and Gniewko (less susceptible), showed a threat of faster development (shorter leaf rust latency period) on triticale triggered by climate change in south-east and south-central Poland than in other regions. The results also showed an increased probability of future regional diversification of leaf rust latency period duration on vulnerable triticale cultivars, opportunities for earlier start of leaf rust epidemics on triticale in Poland and an increase in ?nal disease severity in comparison with 1986–2005.     

(E)-1-(2,3,6-trimethylphenyl)buta-1,3-diene: a potent grape-derived odorant in wine

(E)-1-(2,3,6-Trimethylphenyl)buta-1,3-diene (TPB) was identified as a potent odorant in acid hydrolysates of crude glycoconjugate fractions isolated from grapes and grape vine leaves. TPB was also identified in a Semillon wine, using gas chromatography/mass spectrometry, by co-injection with an authentic sample. TPB had an aroma detection threshold of 40 ng/L in a neutral white wine and the concentration of TPB in four out of five white wines analyzed ranged from 50 to 210 ng/L.     

Effect of Flooding on Contamination of Agricultural Soils with Metals and PAHs: The Middle Vistula Gap Case Study

During the intensive flood in May–June 2010, the floodplains in Little Poland Vistula Gap, used mostly for agriculture, were waterlogged for a period of over 1 month. The aim of the study was to assess the effect of the flood on the level of contamination of the soils in this region. The analysis included basic physicochemical soil properties, contents of ten metals, and concentrations of 16 polycyclic aromatic hydrocarbons (PAHs). The studies cover two territories on opposite sites of the river Vistula (Wilkow and Janowiec) differing in their areas (70 and 4.6 km²) and time of water logging (30 and 10 days). Forty soil samples were collected from both areas immediately after the flood event from the upper (0–30 cm) soil layer together with four samples from the 30–60-cm depth layer. This was supplemented by eight samples from the flood-deposited sediment layer (thickness, 2 cm). The concentrations of identified metals (As, Ba, Cr, Sn, Zn, Cd, Co, Cu, Ni, Pb) at all the sampling points were below the Polish legal limits for the upper layer of soils for agriculture use. The same regarded the median contents of nine PAHs compounds specified in the Polish regulations. In both areas, the median contents of Σ16 PAHs (0.21–0.35 mg kg⁻¹), Zn (10.3–10.6 mg kg⁻¹), Pb (9.2–10.7 mg kg⁻¹), and Cd (0.03 mg kg⁻¹) were much below the mean concentrations of those contaminants in arable soils on the national and European levels. The results show that this severe flooding episode in “clean” agricultural area had no immediate negative impact on the soils as regards the basic physicochemical properties (organic matter content, acidity, nitrogen content) and did not result in excessive soil contamination.     

Phenolic composition and antioxidant properties of Polish blue-berried honeysuckle genotypes by HPLC-DAD-MS, HPLC postcolumn derivatization with ABTS or FC, and TLC with DPPH visualization

In this study, different Polish cultivars of blue-berried honeysuckles (Lonicera caerulea L.), wild and bog bilberry, were analyzed for bioactive compounds. The chemical properties verified included composition of anthocyanins and other polyphenols, antioxidant activity, and profiles of antioxidants by HPLC postcolumn derivatization or TLC. The antioxidant activities of different blue-berried honeysuckle cultivars were similar to that of wild-growing bilberries (ranging from 170 to 417 μmol TE/g dm in ABTS and from 93 to 166 μmol TE/g dm in DPPH and Folin-Ciocalteu tests). The major anthocyanin in the blue-berried honeysuckle was cyanidin-3-glucoside, which constituted 84-92% of the total anthocyanins. The TLC and HPLC postcolumn antioxidant profiles indicated that anthocyanins are the major antioxidants in all berries studied. Wild berries and the cultivars of the blue-berried honeysuckles are also a similar source of such minerals as K, Mg, and Ca.