Search Results (268)

Apple maturation involves profound metabolic reconfiguration, yet systematic trade-offs among bioactive, primary, and volatile metabolites remain unclear, particularly under highland cultivation. We examined nine apple cultivars spanning early-, mid-, and late-maturing groups grown under identical high-altitude conditions (1950 m). Early-maturing cultivars exhibited superior antioxidant activity, with Huashuo (HS) achieving the highest ABTS•⁺ radical scavenging (1268.5 μg Trolox/g) and flavonoid (18.9 mg/g) levels. Conversely, late cultivars accumulated significantly more starch (31.5 mg/g in HFS) and total soluble sugars (121.5 mg/g in Ruixue), whereas sucrose peaked in the early Jinyu (94.4 mg/g). PCA and OPLS-DA models robustly separated maturity groups (predictive variance 65.4%). Late-maturing cultivars exhibited reduced volatile abundance, with 338 compounds downregulated versus only 32 upregulated (VIP > 1, p < 0.05). Compounds with high predicted aroma impact (rOAV ≥ 1), including 2,6-nonadienal (Log₂FC = −3.21) and isobutyl isovalerate (−3.55), were severely depleted, while butanoic acid propyl ester (5.01) increased. Flavor mapping suggested a marked loss of “green” and “fruity” notes in late cultivars. Overall, highland-grown apples exhibit a fundamental metabolic trade-off favoring starch accumulation, a trait commonly associated with storability in late-maturing cultivars. These findings suggest candidate volatile biomarkers for breeding programs that warrant further validation and highlight the potential need for postharvest metabolic interventions to preserve the natural aroma of late-maturing apples. Full article

Sulfur dioxide (SO₂) is a preservative used in the production of fermented beverages for its antimicrobial and reducing properties. However, its effect on the oxidation–reduction potential (ORP, redox potential) during alcoholic fermentation of apple cider has never been recorded. In this study, freshly pressed apple juice was fermented with a 30 mg/L free SO₂ addition (RED) and without an SO₂ addition (CON) prior to alcoholic fermentation. Fermentation kinetics, ORP, basic chemistry, organic acids, nitrogenous compounds, free and total SO₂, glutathione (GSH), phenolics, and volatiles were monitored during alcoholic fermentation and at racking. Additionally, sensory analysis was conducted after bottling. Sulfur dioxide had no effect on fermentation kinetics, nitrogen utilization, ethanol yield, or the volatile composition of the apple ciders at racking. The ORP (vs. Ag/AgCl reference electrode) reached maximum values of 310 mV in CON and 218 mV in RED before alcoholic fermentation, and minimum values of −94 mV and −136 mV, respectively, near peak alcoholic fermentation. Mean ORP values during alcoholic fermentation were −29 mV in CON and −47 mV in RED. No statistical differences were found between the ORP of CON and RED using net area under the curve (AUC) of the ORP relative to Y = 0 mV, nor in the GSH chemistry of the ciders. The addition of SO₂ inhibited malolactic fermentation (MLF) during alcoholic fermentation. As a result, higher concentrations of malic acid and lower concentrations of lactic acid were observed in RED than in CON at racking. Sulfur dioxide additions preserved monomeric, dimeric, and increased the pool of sulfonated flavan-3-ols, likely due to PPO inhibition during the prefermentative phase and reactive oxygen species (ROS) quenching. The sensory composition of the ciders was affected whereby CON showed higher banana aroma and RED trended towards reduction aromas. Overall, SO₂ additions before alcoholic fermentation of apple cider preserved phenolics, inhibited MLF, and increased reduction aroma with no clear effect on fermentation kinetics and ORP, highlighting trade-offs between the impact of SO₂ additions on the chemical and sensory attributes of apple cider. Full article

Background: Fresh-cut apples are highly susceptible to quality deterioration due to enzymatic browning and oxidative degradation of bioactive compounds. This study investigated the effects of conventional polyethylene packaging (PE, Pack 1) and two innovative biodegradable packaging materials (Pack 2 and Pack 3) on the stability of bioactive compounds in fresh-cut Golden Delicious apples during refrigerated storage. Individual phenolic compounds ((+)-catechin, caffeic acid, (−)-epicatechin, p-coumaric acid, rutin, and quercetin) were quantified by HPLC-PDA, while spectrophotometric assays were used to determine total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity (ABTS and DPPH). The environmental performance of the packaging materials was assessed through Life Cycle Assessment (LCA) using SimaPro v.9.5.5. Results: Polyphenol stability was significantly influenced by packaging and storage time (p < 0.001). Compared with fresh-cut apples at t0, Pack 2 promoted a 17.4% increase in total phenolic content after 21 days, whereas Pack 1 and Pack 3 showed reductions of 31.0% and 37.6%, respectively. HPLC analysis revealed compound-specific responses, with rutin and quercetin being markedly better preserved in Pack 3 after 21 days (17.65 and 1.93 mg/100 g, respectively) than in Pack 1 (0.67 and 0.19 mg/100 g, respectively). Two-way ANOVA confirmed significant effects of storage time, packaging, and their interaction on TPC, TFC, ABTS activity, and all individual phenolic compounds (p < 0.001), whereas DPPH activity was not significantly affected (p > 0.05). Pearson correlation (TPC–ABTS, r = 0.6885, p < 0.001) and principal component analysis indicated that antioxidant capacity was more closely associated with the qualitative phenolic profile than with total phenolic concentration alone. LCA highlighted environmental trade-offs among the packaging systems: Pack 1 showed lower impacts in several categories, Pack 2 displayed an intermediate environmental profile, whereas Pack 3 reduced dependence on fossil resources but exhibited higher land- and water-use impacts together with limitations related to end-of-life management. Conclusion: Packaging materials significantly affected the preservation of phenolic compounds and antioxidant activity in fresh-cut apples while exhibiting distinct environmental profiles. The results demonstrate that no packaging system simultaneously maximized product quality and environmental sustainability, highlighting the importance of integrating analytical performance with life-cycle assessment when developing innovative food packaging solutions. Full article

The growing demand for healthier beverages has boosted the development of fruit-based functional drinks, but their real potential depends not only on initial bioactive content but also on the fraction that remains available after digestion (bioaccessibility). This study evaluated the antioxidant capacity and in vitro bioaccessibility of bioactive compounds in a beverage formulated from pineapple, apple, ginger, and cinnamon extracts, with inulin and myo-inositol as complementary ingredients. Three formulations were prepared: F1 (fruit–spice extract), F2 (F1 + inulin), and F3 (F1 + inulin + myo-inositol). Physicochemical parameters (pH, °Brix, reducing sugars, dietary fiber), total phenolic content (Folin–Ciocalteu), and antioxidant capacity (ABTS and FRAP) were measured before and after an adapted INFOGEST gastrointestinal digestion. Bioaccessibility was calculated from the intestinal supernatant. All formulations had pH 3.61, but soluble solids increased from F1 to F3 (6.17–8.97 °Brix). Folin–Ciocalteu values decreased after digestion in all formulations, but F1 retained the highest bioaccessibility (95.05 ± 5.82%), while F2 and F3 showed much lower values (33.28 ± 2.01% and 39.17 ± 5.52%, respectively). ABTS values increased after digestion in all formulations, with bioaccessibility exceeding 100% (125–143%). In contrast, FRAP values dropped sharply after digestion (bioaccessibility 4.59–11.00%), with F2 and F3 showing slightly higher retention than F1. The antioxidant response after digestion is strongly method-dependent and influenced by the beverage matrix. The formulation without inulin and myo-inositol (F1) better preserved the reducing capacity measured by Folin–Ciocalteu, while enriched formulations showed higher FRAP retention. ABTS bioaccessibility increased universally, suggesting release or transformation of radical-scavenging compounds during digestion. This study supports the need to include bioaccessibility assays when evaluating the functional potential of complex fruit-based beverages. Full article

This study investigated the effects of apple, oak, and mesquite wood chip types on the physicochemical properties, VOC profiles, and sensory characteristics of brined smoked goat meat. Boneless muscles were brined in 1% NaCl and randomly assigned to a non-smoked control group or three wood chip-smoked groups. All smoked groups showed significantly lower TBARS values than the control (p < 0.05), indicating improved oxidative stability, whereas pH, cooking loss, and Warner–Bratzler shear force did not differ significantly among groups, indicating that fundamental textural properties were preserved. Notably, mesquite- and oak-smoked meats exhibited significantly higher abundances of key smoke-derived phenolic compounds—including guaiacol, phenol, o-cresol (2-methylphenol), and 2-methoxy-5-methylphenol—and sulfur-containing compounds such as carbon disulfide and hexathiane, which correlated with reduced off-flavor scores and significant improvements in smoke flavor and overall acceptability compared to the control and apple-smoked groups (p < 0.05). These findings demonstrate that smoking goat meat with mesquite or oak wood chips is an effective processing strategy to mask the perception of species-specific off-flavor and enhance overall sensory acceptability. Full article

To address the limitations of conventional point-based sampling methods (e.g., water-sensitive paper and filter paper) in characterizing the three-dimensional deposition distribution on curved fruit surfaces, this study proposed a fruit-surface deposition quantification approach validated through a coupled workflow comprising multi-view 3D reconstruction, target point cloud segmentation, and chemical wash-off quantification. A carmine solution was used as a tracer to simulate pesticide deposition. High-accuracy colored point clouds of apples were generated via multi-view 3D reconstruction, and the target deposition point cloud was automatically extracted using a combined strategy integrating K-means-based coarse color clustering with HSV threshold refinement. The target point cloud count was regressed against the measured single-fruit deposition volume. The results showed a significant linear relationship between the target point cloud count and deposition under both laboratory and real orchard air-assisted spraying conditions (laboratory: R² = 0.827, r = 0.909, n = 13, p < 0.01; orchard: R² = 0.885, r = 0.941, n = 17, p < 0.01). This method can characterize the differences in pesticide deposition among fruits while preserving the three-dimensional location information of the tracer-related region, thus providing a methodological basis for characterizing pesticide deposition on the fruit surface. Full article

Apple harvesting is transitioning from conventional manual picking to harvest-assist platforms, vibration-based mechanical systems, and selective robotic harvesting. For fresh-market apples, harvesting efficiency cannot be evaluated independently of mechanical damage, postharvest quality deterioration, and food-safety risks. Compression bruising, impact bruising, abrasion, cuts, punctures, and stem-end tearing can disrupt the peel, cuticle, and cellular structure to different degrees, triggering reactive oxygen species accumulation, membrane lipid peroxidation, cell-wall degradation, enzymatic browning, and increased respiration and ethylene metabolism. These responses may subsequently be amplified during storage, transportation, and processing, leading to softening, decay, shortened shelf life, and potential patulin contamination. Centered on the damage–safety trade-off, this review compares the technical characteristics and typical damage profiles of manual harvesting, vibration-based mechanical harvesting, harvest-assist platforms, and selective harvesting robots; explains how mechanical damage is transmitted from cellular physiological responses to food-quality and safety outcomes; and proposes conceptual frameworks for a Damage Risk Index and a Harvest Suitability Score. The central objective of intelligent apple harvesting should therefore be to improve efficiency while preserving appearance, texture, nutritional quality, storage stability, and food safety. Full article

Accurate and real-time apple detection in complex orchard environments is essential for robotic harvesting but remains challenging because of illumination variation, foliage occlusion, and limited computational resources. This study proposes Fast-YOLO11n, a lightweight detector derived from the nano variant of You Only Look Once 11 (YOLO11n) and integrating three complementary components. A Fast-C3k2 module based on partial convolution (PConv) reduces redundant computation while preserving cross-layer feature transmission. A focal modulation (FM) mechanism enhances target-related responses and suppresses background interference under occlusion and uneven illumination. In addition, a parallel downsampling module, termed ADown, retains local geometric details and multi-scale semantic information during downsampling. Experiments were conducted on a field-collected orchard dataset comprising 2240 images and 22,673 annotated apple instances under diverse lighting, scale, and occlusion conditions. Fast-YOLO11n achieved mean average precision values of 75.76% across intersection-over-union (IoU) thresholds of 0.50–0.95 (mAP@50–95) and 91.29% at an IoU threshold of 0.50 (mAP@50), while operating at 366.19 frames per second (FPS) with 2.51 million parameters and 6.00 billion floating-point operations (FLOPs). Compared with the YOLO11n baseline, it improved mAP@50–95 and mAP@50 by 2.39 and 1.39 percentage points, respectively, while reducing the parameter count and FLOPs by 2.71% and 5.36%. Ablation experiments demonstrated the individual and combined effects of the three modules on detection performance and computational efficiency. The proposed model provides a favorable balance between detection accuracy and computational efficiency, indicating its potential for real-time orchard perception on resource-constrained platforms. Full article

Chitosan, a chitin-derived biopolymer, is widely used in agriculture and food preservation. Fungal-derived chitosan offers a sustainable alternative to crustacean sources, and Ganoderma lucidum represents a promising source of this functional material. This study characterized fungal chitosan (F.Cs) extracted from G. lucidum cell-wall chitin by FT-IR, molecular weight, viscosity, and degree of deacetylation. Its antimicrobial activity was evaluated in vitro, and its preservative and disease control efficacy against Monilinia fructicola on postharvest apples was compared to commercial chitosan (C.Cs). DNA/protein leakage of the studied FGs and C.Cs were investigated to reveal the antimicrobial mechanisms. In particular, F.Cs exhibited promising in vitro antimicrobial activity, with MIC/MFC values of 0.75/0.75 mg/mL against M. fructicola and 0.75/1.5 mg/mL against Botrytis cinerea, compared to C.Cs. In addition, F.Cs induced greater membrane damage in M. fructicola than C.Cs, as evidenced by higher DNA leakage (24% vs. 13%) and more pronounced protein leakage (102% vs. 98%). In vivo assay demonstrated that F.Cs formed an effective protective coating layer, reducing fruit moisture loss, preserving firmness s, and significantly limiting M. fructicola-induced decay compared to C.Cs. Particularly, F.Cs (1.5%) were most effective, reducing disease incidence to 12.5% (preventive) and 20.8% (curative), with decay rates of 18 and 31%, respectively. C.Cs (1.5%) provided moderate protection, with disease incidences of 37.5 and 43.7% in preventive and curative treatments, respectively. These results demonstrate the superior efficacy of F.Cs over C.Cs in preserving apple quality and enhancing resistance to M. fructicola, highlighting the potential of G. lucidum-derived chitosan as a sustainable, multifunctional biopolymer for postharvest disease control and fruit quality preservation. Full article

Reliable perception of young apple fruits in natural orchards is a prerequisite for automated thinning and intelligent orchard management, yet remains difficult in real field conditions due to small fruit size, dense distribution, branch–leaf occlusion, background similarity, and severe illumination degradation at night. This study presents FruitDet, a lightweight multi-module detector designed for robust day–night young apple fruit detection in complex orchard environments. A field dataset was established in a high-density apple orchard in Aksu, Xinjiang, covering daylight and low-light night-time scenes with diverse occlusion, scale, and illumination variations. To improve detection robustness without sacrificing computational efficiency, FruitDet combines three complementary mechanisms: an inverted-bottleneck-based multi-scale feature enhancement module for preserving small-fruit details, a channel–spatial attention module for suppressing foliage and illumination interference, and a lightweight Transformer-based context module for modeling long-range dependencies between fruits and surrounding orchard structures. In daytime scenes, FruitDet achieved 91.904% precision, 77.557% recall, 83.254% mAP50, and 66.427% mAP50–95; in night-time scenes, it maintained 90.107% precision, 75.135% recall, 80.544% mAP50, and 64.719% mAP50–95. Compared with mainstream detectors including YOLOv5n, YOLOv8n, YOLO11n, YOLO26n, Faster R-CNN, RT-DETR, and RT-DETRv2, FruitDet consistently delivered higher accuracy across lighting conditions. Ablation, visualization, public-dataset testing, and edge-deployment experiments verified that the proposed modules jointly improve small-object representation, background discrimination, low-light robustness, and real-time applicability. With 2.960 M parameters, 3.726 G FLOPs, and approximately 180 FPS, FruitDet offers a practical and efficient visual perception approach for Young fruit monitoring was conducted under both daytime and night-time orchard conditions covered in this study. All-weather orchard monitoring and robotic young-fruit thinning. The shareable data are available Full article

Fresh-cut apples are highly prone to browning during processing and storage. This long-standing problem will cause huge economic losses and restrict the commercial development potential of the fresh-cut fruit industry. In this study, Fuji apples were used as test materials to explore the inhibitory effect and anti-oxidant mechanism of pre-cutting high oxygen treatment (90% O₂, 3 h) combined with post-cutting Withania somnifera extract immersion on the browning of fresh-cut apples. Through the determination of physiological and biochemical indexes and proteomics analysis, the effects of different treatments on the nutritional quality, reactive oxygen species metabolism, membrane lipid peroxidation, anti-oxidant enzyme activity and related protein expression of fresh-cut apples were systematically evaluated. The results showed that after 14 days of storage, the combined treatment group had the lowest browning index of 41.29% and the highest whiteness index of 60.35%, and its color protection effect was significantly better than that of single high oxygen treatment or single extract treatment. The combined treatment could increase the total phenol content to 6.45 mg/g after 7 days of storage, and increase the DPPH free radical scavenging rate to 0.60% after 14 days of storage, significantly enhancing the anti-oxidant capacity. Meanwhile, the combined treatment could maintain higher activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), and maintain the malondialdehyde content at a low level of 0.06 nmol/g after 14 days of storage, effectively delaying the process of membrane lipid peroxidation. However, adverse results were also observed in the study, including the rebound of superoxide anion level (28.16 nmol/g) after 14 days of storage, the highest accumulation of H₂O₂ during the whole storage period, and the significant increase in polyphenol oxidase (PPO) activity (151.14 IU/L) after 14 days of storage, indicating an elevated browning risk under prolonged storage. Proteomics analysis revealed that the combined treatment regulated multiple metabolic pathways, including the up-regulating of glutathione metabolism and pentose phosphate pathway to enhance reactive oxygen species scavenging capacity, as well as the modulation of fatty acid metabolism to preserve cell membrane integrity. Despite the above limitations, the overall browning inhibitory effect of the combined treatment is still better than that of a single treatment, but its pro-oxidant effect and long-term reactive oxygen species regulation effect still need to be further optimized. In summary, pre-cutting high oxygen treatment combined with post-cutting Withania somnifera extract treatment is an effective anti-browning strategy for fresh-cut apples, which can provide a theoretical basis for the development of natural and efficient fresh-cut fruit and vegetable preservation technology. Full article

To control the impact of the invasive crayfish Faxonius limosus on native crayfish and fish biodiversity in the Danube River ecosystem, one possible approach is the valorization of this species through the production of value-added biopolymers, considering the continuously increasing demand for chitosan. However, there are very limited data regarding the utilization of Faxonius limosus shell waste as a source of chitosan. Therefore, this study evaluated chitosan recovery from spiny-cheek crayfish shell, including conventional chemical treatment with different demineralization intensities and numbers of deproteinization steps, as well as ultrasound and autolysis-assisted deproteinization. The obtained chitosans were characterized in terms of yield, moisture content, degree of deacetylation, color, crystallinity and structural properties. Residual heavy metal concentrations (Hg, Cd and Pb) were determined to assess the safety of crayfish shell as a raw material intended for food-related applications. Particular emphasis was placed on gel-related functional properties of obtained chitosans, including rheological behavior, wettability on fruit surfaces, antioxidant and antimicrobial activities, and film-forming ability. These properties govern the formation of structured biopolymeric networks and their performance as active food coating materials. The relationships between the extraction process, physicochemical characteristics and functional performance were investigated to identify the most suitable chitosan for potential food preservation applications. The results demonstrated that extraction conditions significantly affected the physicochemical and functional properties of chitosan. Samples obtained through intensive deproteinization showed enhanced antimicrobial activity, whereas higher antioxidant activity was observed in samples containing residual bioactive compounds. Most formulations exhibited suitable wettability on apple and nectarine surfaces and successfully formed transparent films, indicating their potential application as edible coatings. Full article

Low-light conditions in orchards and facility agriculture hinder accurate fruit recognition. To enhance efficiency in such environments, an optimized semantic contrastive learning-based nighttime fruit image enhancement model, OSCL (Optimized Semantic Contrastive Learning), is proposed. This model integrates semantic contrastive learning for processing low-light fruit images and consists of three modules: image enhancement, semantic segmentation, and contrastive learning. First, the Zero-DCE network is used as the image enhancement network, requiring only input nighttime images for training, resulting in enhanced images through iterative processing. The semantic segmentation module employs a dual attention network (DANet), with a backbone and two parallel attention branches to capture contextual information and meet recognition needs for green fruits. Finally, the VGG-16, known for its regular structure and depth, is selected for feature extraction in the contrastive learning module, effectively analyzing low-light fruit features and preserving information on small fruits. To validate OSCL’s enhancement effect, low-light images of green fruits from apple, persimmon, and pear orchards were collected under active and passive lighting conditions. Both subjective visual assessments and objective numerical evaluations confirmed the model’s efficacy. The generalized peak signal-to-noise ratios (GPSNR) for low-light images processed by OSCL reached 16.23 dB, 15.77 dB, and 15.30 dB under active illumination, and 16.89 dB, 14.38 dB, and 14.17 dB under passive illumination. Overall, OSCL outperforms classical enhancement models, enhancing operational efficiency in low-light conditions. This method offers a theoretical basis for future research on green fruit detection and yield prediction in nighttime environments. Full article

Pre-storage fruit injuries are a major yet often underestimated cause of postharvest losses in apples, particularly during prolonged cold storage. This study evaluated the impact of minor pre-storage injuries on fruit deterioration and assessed the effectiveness of ammonium bicarbonate (2%) and clove bud essential oil (0.2%) as eco-friendly postharvest treatments compared with the fungicide fludioxonil (Scholar). Fresh red and yellow apples were classified as either intact fruit or fruit bearing minor injuries affecting less than 2% of the surface area (approximately 2 mm lesions). Treatments were applied by spraying before storage at 5 °C for six months, followed by 10 days of shelf life at 20 °C. Minor injuries significantly increased postharvest decay, weight loss, and quality deterioration in both cultivars. Injured yellow apples exhibited decay incidence of 17–24% and disease severity of 10.5–17.8%, whereas the more susceptible red apples showed decay incidence of 44.6–60% and disease severity of up to 50%. In contrast, non-injured fruit maintained better physicochemical quality and generally exhibited less than 5% decay incidence. Responses to storage and treatments differed between cultivars. Ammonium bicarbonate effectively reduced decay and helped maintain firmness in yellow apples, providing protection comparable to that of fludioxonil, whereas Scholar was the most effective treatment for reducing decay in red apples. Clove essential oil reduced disease development in non-injured fruit but showed limited effects on firmness preservation. The residual activity of fludioxonil remained detectable after prolonged storage, as demonstrated by inoculation assays performed after storage. The results demonstrate that fruit integrity at harvest is a critical determinant of successful long-term storage and that the benefits of postharvest treatments are substantially reduced when fruit are mechanically injured. Preventive treatment of uninjured fruit with ammonium bicarbonate or Scholar can significantly reduce postharvest losses, while careful handling and sorting to eliminate injured fruit remain essential components of sustainable apple storage management. Full article

Polysaccharides-based bioactive films are regarded as a promising strategy to delay fruit spoilage. β-cyclodextrins (CD) was incorporated into pullulan/Astragalus extract (AE) bioactive films (CD-AE-P) to systematically investigate its effect on multi-scale structures features, physicochemical properties, migration behavior, anti-browning efficacy, and aroma substances in sliced apples. With increasing CD content, a slight blue shift was observed in O-H stretching vibration peak; CD-AE-P films retained an amorphous structure, as evidenced by the disappearance of scattering peak at 0.075 < q < 0.25 nm⁻¹, and they exhibited smoother, continuous fractured surfaces with sparsely distributed protrusions. Meanwhile, CD incorporation contributed to the preservation of macromolecular thermal stability and induced an initial increase followed by a decrease in storage modulus (E′), with CD15-AE-P sample exhibiting the highest Tg value. Although the hydrophilicity increased marginally in the films upon adding CD, WVP decreased progressively, reaching a 23.3% reduction in CD25-AE-P relative to CD0-AE-P. Furthermore, total migration from the films was significantly suppressed by CD incorporation, and the anti-browning effect on sliced apples was extended; notably, treatment with CD25-AE-P effectively preserved the aroma substances of sliced apples during storage. These results demonstrate that CD serves as an effective functional carrier to modulate the effective release of bioactive compounds in active food packaging systems. Full article