Seasonal and Postharvest Changes in Amino Acid Composition in ‘Crimson Crisp’ Apple (Malus domestica Borkh.) in Response to Summer Foliar Urea Applications

Insufficient biologically available nitrogen (N) for yeast is a persistent issue facing cidermakers, whose apple juice base usually does not provide adequate nutrition for a complete fermentation. Cidermakers often supplement their juice with additional yeast assimilable nitrogen (YAN) in the cellar to aid fermentation. The development of biologically available N in apple juice is not well understood. In this study, juice samples from ‘Crimson Crisp®’ apples were taken at several sampling dates in the 2016, 2017, and 2018 growing seasons and analyzed for YAN using formol titration and high-performance liquid chromatography. It was observed that while the total YAN concentration in these apples drops from the period shortly after fruit set to the end of summer, YAN remains stable from several weeks before harvest until the date of harvest. The total YAN did not change after a 6-week postharvest storage period. By contrast, the individual amino acid components of YAN do change during this period. This experiment shows that foliar urea sprays in ‘Crimson Crisp®’ produce an increase in organic N in the juice, mostly in the form of asparagine. Increased organic N impacts yeast growth and sensory characteristics of cider and may be seen as desirable by cider producers.

Pilot Study to Evaluate Performance of Frost-Yuzu Fruit Trees under Protected Cultivation

This study was initiated to observe the performance of yuzu (Citrusjunos Sieb. ex Tanaka) fruit trees when affected by a late freezing in 2018 and to evaluate the recovery of frost-damaged trees during post management under protected cultivation. A—4.9 °C of minimum daily temperature and 40-day drought occurred during dormancy, which then received heavy precipitation between early- and mid-March, with 15 m s−1 more than maximum instantaneous wind speeds frequently observed. This resulted in observed decreases in height, width and volume as well as in fruiting, fruit weight and yield, as well as yield index in 60–90% defoliated yuzu trees, in addition to higher rates of shoot dieback compared to trees that experienced only 0–30% defoliation. Lower performance and recovery rates of trees grown on flat land compared to trees on sloped land were also observed. Tree and net windbreaks did not significantly affect tree vegetative growth and fruit productivity but were found to have lowered shoot mortality in 2018 and 2019. Mulch with an irrigation after freezing or foliar urea application was shown to effectively increase vegetative tree growth and fruit productivity and reduce shoot mortality.

Foliar Urea Applications Increase Yeast Assimilable Nitrogen Concentration and Alcoholic Fermentation Rate in ‘Red Spy’ Apples Used for Cider Production

Yeast assimilable nitrogen (YAN) can be a limiting nutritional factor for Saccharomyces cerevisiae yeast when fermenting apple (Malus ×domestica Borkh.) juice into hard cider. Endogenous YAN concentrations in apples are often below the recommended thresholds to completely use all of the fermentable sugar and minimize the production of off-flavors, such as hydrogen sulfide. Cider producers supplement apple juice with exogenous nitrogen to increase YAN. Urea, commonly applied to apple orchards to increase fruit size and yields, was tested for its ability to increase endogenous apple juice YAN. Starting 6 weeks before harvest in 2017 and 2018, a 1% urea solution was applied to ‘Red Spy’ apple trees one, three, or five times to create low-, medium-, and high-rate treatments, respectively. Relative to the control, the high treatment increased YAN by 229% in 2017 and by 408% in 2018. More than 90% of the YAN in all juice samples was composed of primary amino nitrogen (PAN). Among all treatments, PAN mostly comprised asparagine, and as urea applications increased, the relative concentration of asparagine also increased. Aspartic acid and then glutamic acid were the second and third most abundant amino acids in all treatments, respectively, but comprised less of the total PAN as the number of urea applications increased. Soluble solid concentration, pH, titratable acidity, and total polyphenol concentration were not different among treatments. There was a positive correlation between increased urea application rate and the maximum fermentation rate, which resulted in a shorter fermentation duration. Increasing the number of urea applications was also correlated with greater hydrogen sulfide (H2S) production in juice fermented from fruit harvested in 2017 but not for fruit harvested in 2018. No residual H2S was found in the finished cider from any treatment. Increasing the number of urea applications was estimated to be less expensive than supplementing the juice with Fermaid O™. There would have been no cost savings if Fermaid K™ was used as an exogenous nitrogen source. Foliar urea applications were estimated to be more expensive than supplementing juice with diammonium phosphate. This study demonstrated that foliar urea applications can effectively increase YAN concentration in cider apples while not negatively affecting other juice quality attributes.

Ekmeklik Buğdayda (Triticum aestivum L.) Başaklanma Döneminde Toprak ve Yapraktan Uygulanan Ürenin Tane Verimi ve Kalite Özellikleri Üzerine Etkisi

This study was conducted during two crop seasons to investigate the effect of nitrogen fertilizer quantity and application form on grain yield and quality in Eskisehir Transitional Zone Agricultural Research Institute by using seven bread wheat cultivars in rainfed and eight in irrigated conditions. In the study, urea as a source of nitrogen was applied in heading time (Zadoks 59) in granular and foliar form. In all treatments grain yield, some technological quality characteristics were determined of the genotypes. In both conditions while sedimentation value, protein content, aggregation energy (AGGEN) and maximum torque (BEM) values increased, peak maximum time (PMT) decreased with foliar urea applications. it was determined that there were statistically significant differences between the varieties in terms of SDS sedimentation values in both rainfed and irrigated conditions. In this study, In irrigated and rainfed conditions the values obtained from foliar urea applications compared to granular ones with relation higher bread quality in the genotypes which contain Glu-A1 locus 2* subunit; 9% for grain yield, 6.5% for protein content, 17.0% for sedimentation value and 3.8% increase of BEM, Glu-D1 locus; 5+10 subunit 8% for grain yield, 5.6% for protein content, sedimentation 16.0%, 6.4% for BEM increase, for Glu-B1 locus; 7+9 subunit 7.0% for grain yield, 6.0% for protein content, 19.6% for sedimentation value, and 7.2% for BEM value increase. This study was observed that the foliar application during the heading time provided the improvement of bread wheat grain yield and quality characteristics.