Search Results (184)

Apples are one of the most popular fruits in Germany, valued for their regional availability and health benefits. When deciding which apple to buy, several characteristics are important to consumers, including the taxonomic variety, organic cultivation and regional production. To verify that these characteristics are correctly declared, powerful analytical methods are required. In this study, ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-Q-ToF-MS) is applied in combination with random forest to 193 apple samples for the analysis of various authentication issues. Accuracies of 93.3, 85.5, 85.6 and 90% were achieved for distinguishing between German and non-German, North and South German, organic and conventional apples and for six different taxonomic varieties. Since the classification models largely use different parts of the data, which is shown by variable selection, this method is very well suited to answer different authentication issues with one analytical approach. Full article

The impact of five different nets—conventional black, grey, white, and photoselective red and yellow—on the performance of “Gala Redlum” apples was evaluated over a five-year period (2020–2024) and compared to an uncovered control. The cumulative production over this period, ranked from highest to lowest, was as follows: white net (182.4 t/ha), grey net (178.5 t/ha), yellow net (175.8 t/ha), black net (175.5 t/ha), red net (169.5 t/ha), and uncovered control (138.8 t/ha). Vegetative growth results were inconsistent among the studied years. The cumulative photosynthetic rate (An) was slightly higher under the white net (57.9 µmol m⁻² s⁻¹). Fv/Fm values remained closest to optimal levels under the black and grey nets. Netting effectively protected fruits from elevated temperatures, particularly under the grey net, and reduced sunburn damage, with the grey, black, and yellow nets performing best in this regard. Overall profitability was increased by netting: the black net provided the highest cumulative income per hectare over a five-year period (EUR 72,315) alongside the second-lowest sunburn loss (0.69%), while the yellow net also showed strong economic performance (€64,742) with a moderate sunburn loss (1.26%) compared to the red net. Fruit dry matter and soluble solids content (SSC) were generally higher in the uncovered control, whereas °Hue values tended to be higher under the red and yellow nets. In summary, the black and yellow nets provided more balanced microclimatic conditions that enhanced tree performance, particularly under heat stress, leading to improved yield and profitability. However, the economic feasibility of each net type should be evaluated in relation to its installation and maintenance costs. Full article

Local apple (Malus x domestica Borkh.) cultivars with tolerance to environmental stress factors must be re-evaluated. While the cultivation of apple trees has a long-standing tradition in Hungary, only a handful of cultivars are produced on a large scale, reflecting a trend in global apple production. The most commonly cultivated apple cultivars worldwide include ‘Golden Delicious’, ‘Red Delicious’, ‘Gala’, ‘Fuji’, and ‘Granny Smith’ (with ‘Jonagold’ and ‘Idared’ being significant in Europe). As a result, genetic diversity among apple cultivars has decreased significantly, which has increased the risk of epidemics if a new pathogen appears. Nonetheless, old and local apple cultivars of the Carpathian Basin have adapted well to Hungarian environmental stress factors and pathogens and seem tolerant to them. In this study, fruit analyses and consumer evaluations of eighteen old, local apple cultivars were conducted. Various physicochemical parameters, such as fruit mass, firmness, total soluble solid content, and total acid content, as well as the content of some biological active compounds, including polyphenol content, antioxidant capacity (FRAP), and pectin content, were determined. Additionally, a consumer evaluation was carried out. Based on the results, most of the old, local apple cultivars exhibit high fruit quality and offer considerable health benefits. The proportion of biologically active compounds in these cultivars is equal to or higher than that in the reference cultivar ‘Watson Jonathan’. Based on the excellent fruit quality and consumer preferences, the ‘Harang alma’ (an attractive fruit exhibiting high FRAP values) and ‘Marosszéki piros’ (with firm flesh and a high pectin content and being particularly tasty) cultivars are recommended for backyard gardens. Full article

Lagrein grape (Vitis vinifera L.) pomace and Scilate apple (Malus domestica Borkh.) skin are polyphenol- and antioxidant-rich by-products with promising applications in the food industry. This study investigated the impact of drying and grinding on their antioxidant properties for use in gluten-free baked goods. Regardless of the by-product analysis, the results showed that processing conditions effectively preserved most of the polyphenols. Furthermore, the grape pomace and apple skin flours produced retained approximately 86% and 66% of anthocyanins, respectively. Incorporating these flours into breadsticks, focaccia, and cookies significantly enhanced their polyphenol content (300–727%), anthocyanin content (600–1718%), and antioxidant capacity (280–1200%). The addition of these by-products to baked goods led to a slight decrease in texture and sensory properties. However, adding both grape pomace and apple skin flours significantly improved consumer acceptance compared to products containing only grape pomace flour. This study highlights the potential of upcycling by-products from grapes and apples to enhance the nutritional profile of gluten-free products while supporting a circular economy approach. Full article

Apple (Malus domestica Borkh.) is an economically important fruit. The use of nitrate by plants plays a crucial role in their growth and development, and its absorption and dispersal are controlled by nitrate transport proteins (NRTs). In this study, we investigated the potential function of MdNRT2.4 under low-nitrogen (N) stress by overexpressing it in tobacco. Compared with plants treated with a normal nitrogen level (5 mM), the MdNRT2.4 overexpression lines under low-N stress (0.25 mM) exhibited significantly greater plant height and width, as well as larger leaves and a higher leaf density, than wild-type plants, suggesting that the overexpression of MdNRT2.4 enhances the low-N tolerance of tobacco. Enhanced antioxidant enzyme activities in the MdNRT2.4 overexpression plant lines promoted the scavenging of reactive oxygen species, which reduced damage to their cell membranes. GUS staining of pMdNRT2.4::GUS-transformed Arabidopsis thaliana lines showed that MdNRT2.4 was expressed in the roots, vascular bundles, seeds in fruit pods, and young anther sites, suggesting that MdNRT2.4 mediates the transport of nitrate to these tissues, indicating that MdNRT2.4 might promote nitrate utilization in apple and improve its tolerance to low-N stress. Experiments using yeast one-hybrid and dual-luciferase assays revealed that MdbHLH3 binds to the MdNRT2.4 promoter and activates its expression. MdbHLH3 belongs to the basic helix–loop–helix (bHLH) transcription factor (TF). It is speculated that MdbHLH3 may interact with the promoter of MdNRT2.4 to regulate N metabolism in plants and enhance their low-N tolerance. This study establishes a theoretical framework for investigating the regulatory mechanisms of low-N responsive molecules in apple, while simultaneously providing valuable genetic resources for molecular breeding programs targeting low-N tolerance. Full article

Growing consumer awareness encourages food producers to look for new fortifying additives for muffins. One such additive may be the polysaccharide fraction residue after starch isolation from unripe apples, as they are a source of many bioactive compounds. The aim of the study was to examine the effect of the addition of the polysaccharide fraction residue from unripe apples on the quality and physical properties as well as health-promoting properties of muffins. It was observed that the polysaccharide fraction residue from unripe apples did not deteriorate the texture or volume of muffins and contributed to an increase in the content of polyphenols, and the antioxidant potential of muffins, especially the polysaccharide residue from unripe apples of the Oliwka variety, had a more beneficial effect on the above-mentioned features of muffin than Pyros. Moreover, it was observed that the content of phytosterols (campesterol and cleosterol) in muffins increases but the content of tocopherols decreases due to their thermolability during the baking process. Full article

With the surge in digital farming, real-time quality management of fresh produce has become essential. For apples (Malus domestica Borkh.), consumer demand extends beyond sweetness, texture, and appearance to internal quality factors such as moisture content. Existing non-destructive methods, however, involve costly equipment, complex calibration, and sensitivity to environmental conditions. This study hypothesizes that thermal diffusivity indices derived from surface heating and cooling patterns can accurately predict apple moisture content non-destructively. A total of 823 apples from seven varieties were analyzed using a thermal imaging sensor in a 120-s process comprising 40 s of heating and 80 s of cooling. Key thermal diffusivity indices—minimum, maximum, mean, and max–min values—were extracted and correlated with actual moisture content measured via the drying method. Multiple linear regression and leave-one-out cross-validation confirmed that mean temperature-based models provided the most stable predictions ($R_{CV}^2$ ≥ 0.90 for some varieties). Frame optimization and artificial neural networks further improved prediction accuracy for varieties exhibiting higher variability. The proposed method is cost-effective, requires minimal calibration, and is less affected by surface reflectance, outperforming conventional optical methods (e.g., NIR spectroscopy, hyperspectral imaging), especially regarding robustness against surface reflectance variability and calibration complexity. This offers a practical solution for monitoring apple freshness and quality during sorting and distribution processes, with expanded research on sugar content and acidity expected to accelerate commercialization. Full article

Bee pollen (BP) is a very valuable bee product, and its value depends on its proteins, lipids, amino acids, carbohydrates, vitamins, minerals, and biologically active compounds such as phenolic compounds, which may change depending on the method of pollen preparation after collection and its storage conditions. Therefore, it is very important to determine when the decline in bioactive compounds in BP occurs during storage. The purpose of this study was to evaluate the changes in the content of ascorbic acid and phenolic compounds, and to determine the antioxidant activity of BP extracts depending on their preparation method and storage conditions over a 15-month period, with assessments conducted every 3 months. Dried pollen (at +28 °C on the first day and +35 °C on the second day) and frozen (−20 °C and −80 °C) BP samples were prepared. After 3 months of storage, there was no decrease of ascorbic acid in frozen BP; however, it decreased by 20% in dried BP (p < 0.05). It was determined that in frozen BP, the content of total phenolic compounds decreased by 12–14% (p < 0.05) after 6 months, and in dried BP, it decreased by 7% (p < 0.05) after 3 months. The levels of flavonoids decreased by 10–17% (p < 0.05) in BP after 6 months. Chlorogenic and p-coumaric acids have been observed as the most abundant phenolic acids in BP. During storage (the 6–15-month period), the strongest antiradical and reducing activity in vitro was estimated in the frozen (−80 °C) BP, which was 1.8–3.4-fold and 2.6–3.1-fold higher, respectively, compared to the dried BP extracts. In conclusion, significant results were obtained, showing better stability of phenolic compounds and ascorbic acid during storage in frozen BP compared to dried pollen. Melisopalynological analysis revealed a polyfloral pollen mixture, with Salix spp. and Brassica napus L. predominating in all samples, comprising 34.3% and 36.8%, respectively. Among these, Acer platanoides L., Malus domestica Borkh., and Taraxacum officinale L. were important minor pollens present in the samples examined. Full article

Peel coloration in bicolored apples is decisive for their commercial value and varieties like ‘Nicoter’ and ‘Rosy Glow’ need to achieve 33 and 40% red peel color to be marketed under the trade names ‘Kanzi^®’ and ‘Pink Lady^®’, respectively. Pneumatic defoliation of apple trees is a novel technique to lower the amount of leaf area and, along with pre-harvest pruning, it can improve peel coloration by increasing sunlight incidence on fruit. Our experiments showed that in fact the color index and the amount of anthocyanins, the latter being responsible for the red fruit peel, increased up to 100% after pneumatic defoliation (PD) and pre-harvest pruning (P), or their combination (P+PD), over three years. Anthocyanin contents in ‘Rosy Glow’ apple peels rose irrespective of the orientation and side of the fruit, while in ‘Nicoter’ they increased only on the sun-exposed fruit side. The extent depended on the harvest year and its meteorological conditions and our results showed that the effect is greater in years with high pre-harvest temperatures. In most combinations of year and variety, the three treatments P, PD and P+PD were equally effective. Full article

Apple production in Western Norway faces challenges due to climatic constraints and varying phenology. It is essential for cultivars to adapt to regional ecological factors, while suitable pollinators are necessary for successful cultivation. This study examined the reproductive biology of two newly introduced apple cultivars, ‘Eden’ (Wursixo) and ‘Fryd’ (Wuranda), over two years (2022–2023). Key qualitative and quantitative parameters of reproductive biology were analyzed, including in vitro pollen germination, pollen tube growth within the style and ovary locules, flowering overlap time, and fruit set. The study involved cross-pollination between the pollen recipient cultivars ‘Eden’ and ‘Fryd’, with various pollenizers: ‘Rubinstep’, ‘Red Aroma’, ‘Elstar’, ‘Asfari’ and ‘Professor Sprenger’, as well as self-pollination and open pollination. According to the results from the progamic phase of fertilization and fruit set, the cultivars ‘Rubinstep’, ‘Asfari’, and ‘Fryd’ were the best pollenizers for ‘Eden’. In contrast, ‘Rubinstep’, ‘Eden’, and ‘Elstar’ were the best pollenizers for ‘Fryd’. Looking only at the overlapping of the flowering time between pollen recipient and pollen donor, ‘Professor Sprenger’ and ‘Fryd’ were the best pollenizers for ‘Eden’, while ‘Professor Sprenger’ and ‘Eden’ were good pollenizers for ‘Fryd’. Full article

Temperature changes strongly affect apple development and quality. In this study, we analyze the relationships between the main factors modulating both of the aforementioned processes in the fruits of four apple cultivars. We assessed three-dimensional data concerning the expression profile (fold change) of eight genes related to fruit ripeness regulation (involved in the cell respiration process and sorbitol metabolism as well as encoding cell kinase receptors) and fruit parameters such as fruit weight, ethylene concentration, concentration of soluble solids and acidity, which are affected by seasonal temperature variations (2018–2020). We observed that low temperatures (before the apple ripening phase) promoted an increase in gene activity and improved the fruit quality of the following cultivars: early-flowering/mid-ripening ‘Pink Braeburn’ and ‘Pinokio’, early-flowering/late-ripening ‘Ligol’ and late-flowering/late-ripening ‘Ligolina’. We confirmed the positive effect of low temperatures on the activity of the AAAA1, AALA1, StG and AAXA genes and on the evaluated fruit quality parameters, and we confirmed their dependence on the genotype of the studied cultivars. The obtained results shed light on the complexity of the variability mechanism in fruit features and fruit harvest dates. This knowledge may improve breeding programs for the production of better-quality apples. Full article

The experiment aimed to evaluate the effectiveness of using high doses of nitrogen (N) and delaying the sowing of living mulch in the apple tree (Malus domestica Borkh.) orchard as factors stimulating tree growth and influencing fruit quality. Blue fescue (Festuca ovina L.), as a cover crop, was sown in the tree rows in the second and fourth year after tree planting. It was compared to herbicide fallow control treatment. In each floor management, four N doses (50, 80, 110, and 140 kg ha⁻¹) were used every year. The study indicated the dominance of living mulch, especially sowing in the second year after tree planting as a factor influencing the reduction in growth and yield but improving the red blush surface on the fruit skin. The growth of trees was also strongly influenced by biotic and abiotic stress factors, which did not allow for a clear assessment of N fertilization. With objectively low cropping levels and poor growth of all trees tested in the experiment, their N needs were satisfied by a dose of 50 kg ha⁻¹. The application of the highest dose of 140 kg N ha⁻¹ had a significant and negative impact on the red color of the fruit skin. Full article

Apple (Malus domestica Borkh.) juice is a globally popular beverage that is valued for its pleasing flavor, wide availability, and health benefits, including support for cardiovascular health and antioxidant properties. A critical element of the production process is the clarification procedure, which improves the product’s purity, visual appeal, and shelf stability by removing solids, colloids, and polyphenols. This study examines the efficacy of plant-based clarifiers, LittoFresh Liquid and FloaClair, in combination with three mineral agents—KlarSol30, GranuBent Pore-Tec, and Seporit Pore-Tec—on the quality of apple juice. The following analytical procedures were conducted: measurement of turbidity (NTU), color stability (ΔE*), transmittance at 440 nm, antioxidant capacity (FRAP), and total polyphenol content (TPC). The results showed that plant-based clarifiers were effective in reducing turbidity by up to 45% while improving transmittance levels by an average of 30% compared to untreated samples. Additionally, plant-based agents retained up to 20% more polyphenols and exhibited a 15% higher antioxidant capacity than traditional gelatin-based clarifiers. Full article

Apples (Malus domestica Borkh.) represent one of the most widely cultivated and consumed fruits globally, with significant genetic diversity among cultivars. This study aimed to evaluate the morphological, biochemical, and organoleptic characteristics of 34 apple cultivars, including ancient Romanian varieties, internationally old and modern cultivars, and new selections. The assessment was conducted to identify valuable traits for breeding programs and commercial applications. Morphological analysis revealed significant variation in fruit size, shape, and weight, with international ‘classic’ cultivars exhibiting larger dimensions on average. Biochemical profiling indicated notable differences in moisture content, total soluble solids, titratable acidity, and carotenoid levels, with some traditional cultivars demonstrating high nutritional potential. Texture analysis showed variations in peel hardness, flesh firmness, and toughness, influencing storage capacity and consumer preference. Organoleptic evaluations highlighted the superior sensory attributes of cultivars such as ‘Golden Orange’, ‘Jonathan’, ‘Kaltherer Böhmer’, and ‘Golden Delicious’, which ranked highest in terms of taste, aroma, and juiciness. Statistical analyses, including principal component and hierarchical clustering analyses, further distinguished cultivars based on their physicochemical and sensory profiles. The findings emphasize the importance of genetic diversity in apples in maintaining a resilient and sustainable assortment. This study provides valuable insights for breeding programs and for orchard, market, and apple industry development. We also highlight future directions, promoting the conservation and strategic use of both traditional and modern cultivars. Full article

Rootstocks largely determine the tree architecture of the grafted scions, significantly affects yield, suitability for mechanical harvesting, and planting pattern of apple orchards. It is thus important to reveal the mechanisms behind the rootstocks influence on the tree architecture of scions in apple trees. This study analyzed the grafting survival rate, the physiological parameters including plant growth, photosynthesis and nutrient accumulation in the apple variety ‘Harlikar’ with eight apple rootstocks. We also explored the mechanism of scion architecture formation using transcriptomics based on different scion/rootstock combinations. The results indicated that ‘Harlikar’ had the lowest grafting survival rate with rootstock ‘M26’, with less callus formed at the graft interface, foliage etiolation, and weak photosynthetic capacity. While ‘Harlikar’ had better affinities with ‘M9-T337’, ‘M9-Nic29’, ‘M9-Pajam2’, ‘B9’, ‘71-3-150’, ‘Qingzhen 2’, and ‘Malus baccata’. Among these, the highest plant height and the highest number of lateral branches were observed in ‘Harlikar’ with rootstock ‘Qingzhen 2’, they were 1.12-times and 2.0-times higher than ‘Harlikar’ with vigorous rootstock ‘M. baccata’, respectively. The highest accumulations of total nitrogen, total phosphorus, and total potassium in scions were observed in ‘Harlikar’/‘Qingzhen 2’, they were 2.22-times, 2.10-times, and 11.80-times higher than that in ‘Harlikar’/‘M. baccata’. The lowest plant height was observed in ‘Harlikar’/‘71-3-150’, only 50.47% of ‘Harlikar’/‘Qingzhen 2’ and 56.51% of ‘Harlikar’/‘M. baccata’, and the lowest internode length was observed in ‘Harlikar’/‘M9-Nic29’, only 60.76% of ‘Harlikar’/‘Qingzhen 2’ and 79.11% of ‘Harlikar’/‘M. baccata’. The transcriptome, weighted gene co-expression network and KEGG enrichment analyses revealed that, compared to ‘Harlikar’/‘M. baccata’, most differentially expressed genes screened from ‘Harlikar’/‘Qingzhen 2’, ‘Harlikar’/‘71-3-150’, and ‘Harlikar’/‘M9-Nic29’ were enriched in hormone signal transduction pathways. Specifically, auxin-repressed protein gene ARP, cytokinin synthesis related genes CKXs and CYP92A6, and brassinosteroid synthesis related gene CYP87A3 were involved in the dwarfing of ‘Harlikar’/‘71-3-150’ and ‘Harlikar’/‘M9-Nic29’. Cytokinin synthesis related gene ARR-A and abscisic acid-responsive element binding factor gene ABF were the key to increased branching in ‘Harlikar’/‘Qingzhen 2’. In addition, acid phosphatase genes ACPs, and serine/threonine-protein kinase genes PBLs were involved in the vegetative growth of scions in ‘Harlikar’/‘Qingzhen 2’ by affecting the absorption and utilization of nutrients. These results provide theoretical guidance for cultivating high-quality ‘Harlikar’ apple trees and elucidate the molecular mechanisms regulating plant height and lateral branch formation in apple. Full article