Prediction of baking results from farinograph measurements by using stepwise linear regression and artificial neuronal networks

In an effort to extract additional data from farinograph experiments a model was developed to simulate the measurements and correlate the parameters of the model with results from baking tests. This additional information can be used in bakeries to predict the baking properties of the flours and adjust the recipes to maintain a constant product quality. For this eight different flours were characterized with a farinograph and 13 different results from baking experiments. An approach with five nonlinear differential equations was able to model the farinograph measurements very well (average R² = 0.995 ± 0.005). While a stepwise multilinear regression only showed weak correlations in cross validation between a single parameter of the model and the baking volume (R² = 0.745) and the volume yield (R² = 0.796) respectively, the artificial neuronal network was more successful. For the baking weight (R² = 0.926), the dough yield gross (R² = 0.909) and net (R² = 0.913) strong correlations were found. A good correlation for the baking volume (R² = 0.853) was also determined, while the volume yield showed comparable results to the linear regression (R² = 0.792).     

Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.     

An investigation on the effect of heat-moisture treatment on baking quality of wheat by using response surface methodology

Effect of heat-moisture treatment on quality properties of two bread wheats (cvs. Tosunbey and Bayraktar) were investigated by using response surface methodology (RSM). Temperature and moisture conditions in the experimental design were in the range of 55–95 °C and 13–19%. Heat-moisture treated grains were milled into flour and quality properties were determined. The optimum moisture-temperature combination for the highest dry gluten, Zeleny sedimentation, Alveograph W and bread volume values were estimated as 14%-63 °C for Tosunbey and 19%-55 °C for Bayraktar samples. Alveograph W seems to be a good indicator of baking quality for wheats treated at higher temperatures. In order to describe the relationship between the dependent and independent variables (moisture, temperature), the response values were fitted by second order polynomial models. Significance analysis showed that the effect of both moisture and temperature on dry gluten content, sedimentation and falling number values for Tosunbey; falling number and damaged starch values for Bayraktar were significant (p < 0.05). The effect of temperature on Farinograph water absorption, W and P/G, bread volume and firmness values were significant for both cultivars (p < 0.05). It can be concluded that improvement in baking quality can be achieved and flours with different properties can be produced by heat-moisture treatments on wheat.     

Genome-wide association mapping of phenolic acids in tetraploid wheats

Phenolic acids are major components of cell walls in wheat and have important implications on human health as antioxidants with anti-tumor activity. Our objectives were to identify phenolic acid genes in wheat by single nucleotide polymorphisms (SNPs) detected within the coding sequences of candidate genes, and to identify chromosomal regions associated with single phenolic acids and total soluble phenolic compounds. A set of candidate genes involved in the biosynthesis of hydroxycinnamic acid derivatives were identified by comparative genomics. SNPs found in the coding sequences of six genes (PAL1, PAL2, C4H, C3H, COMT1 and COMT2) were used to determine their chromosomal location and accurate map position on two reference consensus linkage maps. The genome-wide association study (GWAS), based on genotyping a tetraploid wheat collection with 81,587 gene-associated SNPs, detected 22 quantitative trait loci (QTL) distributed on almost all durum wheat chromosomes. Two QTL for p-coumaric acid were coincident with the phenylalanine ammonia-lyase (PAL2) and p-coumarate 3-hydroxylase (C3H) genes on chromosome arms 2AL and 1AL, respectively. The availability of candidate gene-based markers can allow elucidating the mechanism of phenolic acids accumulation in wheat kernels and exploiting the genetic variability of phenolic acids content for the nutritional improvement of wheat end-products.     

The importance of native valley oaks (Quercus lobata) as stopover habitat for migratory songbirds in urban Sacramento,California, USA

Urban development occupies over 375,000 ha (6%) of California's Central Valley, and expansion continues to displace natural and agricultural landscapes. The value of urban areas as habitat for native wildlife and the characteristics that determine its value, however, remain little studied. Many Neotropical migrant passerine bird species are declining due to changes in breeding, migratory, and wintering habitats and climatic conditions. During 2010–2013, we evaluated the importance of native valley oak (Quercus lobata) as stopover foraging habitat used by Neotropical migrant birds in urban areas of the Sacramento region in California, USA. Over 3 years, we surveyed spring and late summer-early fall migrant songbirds and measured tree canopy cover within 31 c.0.91 ha transects in Curtis Park, an older residential neighborhood. We detected 607 individuals from 20 migrant species, but four wood warblers comprised the bulk of observations: black-throated gray (Setophaga nigrescens), Wilson's (Cardellina pusilla), orange-crowned (Oreothlypis celata), and yellow warblers (Setophaga petechia). Migrant abundance was closely correlated with valley oak canopy abundance and increased linearly with oak canopy especially during fall migration. Migrants were nearly absent from areas lacking oak canopy. Migrant bird species as a group also foraged in valley oak substantially more often (74%) than would be expected based on its 15% relative canopy cover (χ²_1d.f. = 924, p < 0.0001), as did all species whose selectivity could be tested. These results are important in demonstrating previously undocumented migrant use of urban areas with remnant valley oak canopy and suggest that protecting existing valley oaks and increasing their use in future urban forestry and landscape plantings in the Central Valley could provide substantial habitat benefits for native migratory birds.     

Effect of process conditions and amylose/amylopectin ratio on the pasting behavior of maize starch: A modeling approach

The effects of different process conditions on the pasting behavior of the 14%, w/w suspensions of high amylose, waxy and normal maize starches at mixing speeds of 50, 160 and 250 rpm with the heating rates of 2.5, 5 and 10 °C/min were investigated. In addition, the impact of the starch mixture with an amylose-amylopectin ratio of 0–70% at 160 rpm and a heating rate of 5 °C/min on the pasting parameters was studied. According to the results, when stirring speed decreased from 250 rpm to 50 rpm, the peak viscosity dramatically increased. Furthermore, both heating and stirring rates significantly affected the pasting properties (p < 0.05). The amylose content of maize starch had a negative correlation with peak viscosity, trough viscosity, breakdown viscosity, final viscosity, and setback viscosity. Besides, syneresis values decreased as amylose content decreased from 70% to 0%. According to the kinetic modelling of pasting curves, starch coefficients were found to be higher than 1 for all starches, indicating that the penetration of water into starch granules increased granule swelling rate. The findings of the present study confirmed that both process conditions and amylose/amylopectin ratio can be optimized without necessity of starch modification to obtain the products with the desired quality.     

Micro-scale heterogeneity in urban forest soils affects fine root foraging by ornamental seedlings of Buddhist pine and Northeast yew

Urban soils are frequently characterized by a strong heterogeneity caused by intense anthropogenic activity and land use changes. Soil heterogeneity is commonly known to affect tree root development, but little has been detected concerning root foraging by ornamental trees in heterogeneous urban soils at micro-scale. In this study, Buddhist pine [Podocarpus macrophyllus (Thunb.) D. Don] and Northeast yew (Taxus cuspidata S. et Z.) were selected as ornamental tree species for a two-year study. In the first-year, seedlings were cultured under contrasting photoperiods to generate different morphologies. In the second year, seedlings were transplanted to pots filled with soils collected from an urban forest. Controlled-release fertilizers (N-P₂O₅-K₂O, 14-13-13) were evenly broadcasted to a half patch of the pot (heterogeneity) or to both halves (homogeneity) on the surface 5 cm beneath the pot-top at the rate of 0.135 g N seedling⁻¹. In the fertilized heterogeneous patch, larger Buddhist pine seedlings had greater dry weight, length, surface area, volume, number of tips, and morphological foraging-precision in fine roots. Compared to Northeast yew seedlings under natural photoperiod in the first year, those under the extended photoperiod had larger size, greater fine root biomass, and length but lower foraging-precision in the second year. N and P concentrations in second-year fine roots mainly increased with the availability of patches generated by fertilization for both species. In conclusion, the ability to forage for nutrients by ornamental tree seedlings in heterogeneous urban forest soils was species-specific. Buddhist pine seedlings had higher foraging precision in heterogeneous urban soils than Northeast yew seedlings due to their response to the extended photoperiod during culture.     

Evaluation of alternative sanitizers to chlorine disinfection for reducing foodborne pathogens in fresh-cut apple

The risk of undesirable by-products from chlorine disinfection in fresh-cut industries, together with its limited efficacy, has led to a search for alternative agents. The aim of this study was to test several alternative putative antimicrobial substances to reduce Escherichia coli O157:H7, Salmonella spp. and Listeria spp. populations on fresh-cut apple. Carvacrol, vanillin, peroxyacetic acid, hydrogen peroxide, N-acetyl-l-cysteine and Citrox were selected for their results in in vitro assays against E. coli O157:H7 and Listeria spp., to be tested on fresh-cut apple plugs. Apple flesh was inoculated by dipping in a suspension of a mix of the studied pathogens at 10⁶ cfu mL^?1, and then treated with the antimicrobial substances. All treatments were compared to deionized water and a standard sodium hypochlorite treatment (SH, 100 mg L^?1, pH 6.5). Pathogen population on apple plugs was monitored for up to 6 days at 10 °C. Bacterial reductions obtained by peroxyacetic acid (80 and 120 mg L^?1), vanillin (12 g L^?1), hydrogen peroxide (5, 10, 20 mL L^?1) and N-acetyl-l-cysteine (5 and 10 g L^?1) were similar or higher than reduction obtained by SH. In addition, bacterial populations were maintained at low levels throughout storage. No cells of any of the pathogens were detected in the peroxyacetic acid, hydrogen peroxide, Citrox and SH washing solutions after apple treatment. Peroxyacetic acid, hydrogen peroxide and N-acetyl-l-cysteine could be potential disinfectants for the fresh-cut industry as an alternative to chlorine disinfection. However, their effect on sensory quality and effectiveness under commercial processing conditions should be evaluated.     

Changes in the properties of rice varieties with different amylose content on dry heat parboiling

Dry heat parboiling is a unique paddy processing technique that has been scarcely exploited. Dry heat parboiling at high temperature for short time and low temperature for long time on physical and physicochemical properties of three rice varieties differing in amylose content were studied. Hardness of the kernels increased from 66.4 N, 68.8 N and 59.8 N in raw samples to 89.1 N, 86.9 N and 59.8 N in parboiled high amylose, low amylose and waxy rice samples respectively. Rapid migration and evaporation of water from severely heated kernels caused cavity formation at the centre. Irreversible damage of amylopectin structures to leachable fractions caused continuous rise of the pasting curve. Crystallinity was thereby reduced. Parboiled high amylose samples gave X-ray diffraction patterns with peaks characteristic of A, B and V-type starch crystallinity. Crystalline starch-lipid complexes were observed in low amylose and waxy rices. The significant increase in the amount of rapidly digestible starch from 56.7%, 61.7% and 66.6% in raw samples to 92.1%, 90.8% and 94.8% respectively in severely processed rice samples and subsequent reduction in resistant starch from 24.5%, 21.2% and 18.4% to 0.4%, 1.9% and 0.1% indicated possibilities for targeted food use of the dry heat parboiled samples.