Changes In Quality Research Articles

Ensiling of Willow and Poplar Biomass Is Improved by Ensiling Additives

Biomass from willow and poplar harvested for feed during the growing season may be preserved by ensiling; however, little research has focused on ensiling of these biomasses. This study focuses on the use of ensiling additives to reduce the pH to around 4.0 to secure stable storage. Lab-scale ensiling experiments were conducted with different willow and poplar clones, shoot ages, and harvest times (June or September). Ensiling without additives often resulted in limited pH reduction. The pH could be reduced in the biomass of both species by adding formic acid, and the required dose to reduce the pH to 4.0 (buffering capacity, BC) ranged significantly between biomass types but was in the range of 2–5 kg formic acid (78%) per ton fresh weight. BC decreased with increasing dry matter (DM) content and decreasing crude protein content. The pH could also be reduced during ensiling by applying molasses and/or lactic acid bacteria, although not sufficiently in poplar. Willow biomass was ensiled effectively at the pilot scale with less than 7% DM loss by adding formic acid or by mixing with grass biomass. Comparable pH results were obtained at the lab scale and pilot scale. The study demonstrates how willow and poplar can be ensiled; however, more research is needed on quality changes during ensiling.

Quality of life after stereotactic radiosurgery for brain metastasis: an assessment from a prospective national registry.

Stereotactic radiosurgery (SRS) is frequently used in the management of brain metastasis patients. However, there is an urgent need to evaluate post-treatment outcomes and quality of life metrics for patients undergoing SRS for brain metastases. The NeuroPoint Alliance (NPA) SRS Quality Registry conducted prospective enrollment of patients undergoing SRS from 2017 to 2024. Patients with brain metastases from lung cancer, breast cancer, and melanoma were included in the analysis. Outcomes of interest included quality of life metrics, as captured by the five-dimension Euro-QOL (EQ-5D) at 6-12 months and last record follow-up, overall survival, local progression, out-of-field progression, and overall intracranial progression. 522 patients comprised our analytic cohort, and 315 patients had available EQ-5D data at the time of SRS and final follow-up. 264 (47.8%), 197 (35.7%), and 91 (16.5%) patients had 1, 2-4, and 5-14 lesions pre-SRS, respectively. The median overall survival time from diagnosis was 27.3 months. The median time-to-local progression was not reached. At final follow-up, 107 (34.0%) patients had improvement, 51 (16.2%) patients had stable, and 113 patients (35.9%) had worsening EQ-5D scores when compared to baseline. For 44 (13.9%) patients mixed responses across the EQ-5D indices were reported. Linear regression analysis showed that male sex, smoking status, primary tumor type, time-to-overall progression, cumulative intracranial tumor volume (CITV), and baseline EQ-5D were statistically significantly associated with EQ-5D single index at the final follow-up. Real-world data from the SRS NPA Registry demonstrated that most patients with brain metastasis had no change or improvement in quality of life after SRS. Baseline EQ-5D was predictive of EQ-5D single index at final follow-up, and, as such, EQ-5D at baseline would be a valuable assessment measure for brain metastasis patients undergoing SRS.

Supplemental Material for Long-Term Effects of Changes in Coparenting Quality During the COVID-19 Pandemic

Supplemental Material for Long-Term Effects of Changes in Coparenting Quality During the COVID-19 Pandemic

Impacts of Large Hydropower Projects on the Ecological Environment of Watersheds: A Case Study of Ertan Reservoir Area

Ertan Hydroelectric Power Station was the first large-scale water conservancy facility in western China, and with its completion, the ecological pattern of the reservoir area has changed dramatically; however, the changes in habitat quality before and after the completion of the reservoir have not yet been systematically monitored and evaluated. In this study, we analyzed the spatial and temporal characteristics of the remote sensing ecological index (RSEI), used CA-Markov model and GeoDetector, evaluated the ecological environment of the Ertan Reservoir area in each five-year period from 1995 to 2020, simulated the ecological quality of the Ertan Reservoir area in 2025, and revealed the nine drivers and their interactions affecting ecological quality of the watershed from a geologic point of view, and finally put forward reasonable planning and targeted protection suggestions. Finally, rational planning and targeted protection recommendations were proposed. The main results were as follows: (1) After the completion of the Ertan Hydropower Station, the spatial distribution of the RSEI in the reservoir area varied significantly, with a trend of “rising-declining-rising” in time, and the area share of “good” area increased the most, by 19.83%. (2) The degree of grading of each driving factor had different degrees of influence on the size of the RSEI value, and its interaction enhanced the spatial differentiation of the RSEI. (3) The average value of the RSEI is 0.66 in 2025, and the ecological environment quality will show a steady improvement in five years. The results of the study can provide a reference for constructing RSEI indicators for large hydropower facilities.

An Evidential Reasoning Method of Comprehensive Evaluation of Water Quality Based on Gaussian Distribution

This study provides an evidential reasoning method for water quality evaluation based on Gaussian distribution to handle the problem of comprehensive water quality evaluation for a region across a period (multiple sections and multiple time points). The method turns the collection of observed water quality indicator values into a probability distribution of water quality grades by using the Gaussian distribution to compute the confidence assessment of water quality grades over one period. It eliminates the subjectivity involved in determining confidence levels and the problem of information loss during data fusion that arises with conventional approaches. The probability distribution of each assessment grade is then determined by repeatedly synthesizing evidence of the same water quality grade using the improved evidential reasoning synthesis rule. To avoid the subjectivity included in experience-based weight settings, principal component analysis (PCA) is utilized to calculate the weights of water quality indicators based on contribution rates and load coefficients. In the end, utility theory is presented to modify the discrete probability distribution of precise numerical expressions, offering thorough results for the evaluation of water quality and facilitating the comparison of various water quality grades. Using the Xiangjiang River Basin as a case study, the proposed evaluation method is contrasted with popular techniques for assessing water quality, including the Single-Factor Evaluation Method, the Fuzzy Comprehensive Evaluation Method, and the Evidential Reasoning Comprehensive Evaluation Method. The findings suggest that the evidence reasoning approach for evaluating water quality that is based on Gaussian distribution is more rational, accurate, and scientific. Additionally, empirical studies on the annual water quality trends in various regions, the upstream, midstream, and downstream trends, and the water quality trends during wet and dry periods are conducted using this method to assess and analyze changes in water quality in the Xiangjiang River Basin during the “11th Five-Year Plan” and “12th Five-Year Plan” periods. The analysis findings demonstrate that, even if the rate of progress has slowed, the Xiangjiang River Basin’s overall water quality has been steadily improving since management and protection measures were put in place. This shows that the preventive and control efforts implemented in the “11th Five-Year Plan” and “12th Five-Year Plan” periods were successful; nevertheless, carrying out the current tactics might only have a limited impact. As a result, more advanced and creative approaches are required to encourage the ongoing enhancement of the water quality in the Xiangjiang River Basin.

Indirect effects of soil warming on litter decomposition via changes in litter quality of dominant tree species in three cool-temperate forests

Indirect effects of soil warming on litter decomposition via changes in litter quality of dominant tree species in three cool-temperate forests

The Effect of Reduced Nitrogen Fertilizer Application on japonica Rice Based on Volatile Metabolomics Analysis.

Nitrogen is critical for rice yield and quality, but its overuse can be detrimental to efficiency and the environment. To identify changes in the quality of rice in response to the reduced application of nitrogen fertilizer, we carried out a comprehensive metabolomics study of SuiJing 18 using volatile metabolomics methods. Our results showed that SuiJing 18 had a total of 358 volatile metabolites, mainly lipids (16.25%), terpenoids (15.41%), heterocyclic compounds (15.13%), and hydrocarbons (13.45%). SuiJing 18 underwent significant changes in response to the reduced application of nitrogen fertilizer. Key sweet volatile compounds such as 4-methyl-benzeneacetaldehyde, hexyl acetate, and 2-methylnaphthalene were present at significantly higher levels when nitrogen fertilizer was applied at a rate of 68 kg of pure nitrogen per hectare, and their flavor characteristics also differed significantly from the compounds resulting from the other two treatments. Focusing on 16 differential volatile metabolites, we further investigated their effects on flavor and quality, thus laying the foundation for a greater understanding of the biomarkers associated with changes in rice quality. This study contributes to a better understanding of the mechanisms underlying changes in rice quality after reduced nitrogen fertilizer application.

Brain encoding during perceived control as a prospective predictor of improvement in quality of life.

Perceived control is strongly related to mental health and well-being. Specifically, lack of perceived control has been associated with learned helplessness and stress-related disorders, such as depression and anxiety. However, it is unknown whether brain activation to control and its protective effect against stress can predict changes in quality of life. To address this gap, we examined the neural underpinning of controllability in healthy females (N=40) performing the Value of Control task in an fMRI scanner. Quality of life and perceived stress were assessed at baseline and 6-month follow-up. Increased brain activation for control was found within the putamen, insula, thalamus, mid-cingulate, dorsolateral prefrontal cortex, motor cortex, and cerebellum. In contrast, increased brain activation for lack of control was found within the posterior cingulate and prefrontal cortices. In an exploratory analysis, an elastic-net algorithm was used to identify brain predictors of quality of life 6 months later. The right putamen's activation to control was selected as the best prospective predictor of improvement in life enjoyment and satisfaction and this association was mediated by changes in perceived stress. Our findings suggest that neural responsiveness to control may have utility as a potential marker of quality of life and resilience to adversity.

Habitat quality assessment on the Qinghai-Tibet plateau across vegetation ecoregions using InVEST and Geodetector models

IntroductionThe Qinghai-Tibet Plateau holds a significant position in the global ecosystem, with its unique high altitude and complex geographical features fostering rich biodiversity. The plateau’s high-altitude environment and distinctive climate system significantly influence the Asian monsoon and regional hydrological cycles. Its vast glaciers and snow reserves are crucial in regulating the Asian climate. While previous studies have analyzed the habitat quality of the Qinghai-Tibet Plateau, significant variations exist across different vegetation ecoregions, warranting further investigation into these variations and their influencing factors.MethodsThis study conducted a comprehensive assessment of habitat quality on the Qinghai-Tibet Plateau by analyzing the impacts of human activities, climate change, and grazing intensity. Using the InVEST Model and Geodetector Model, we evaluated habitat quality across the plateau’s six vegetation ecoregions from 2000 to 2020. The efficacy of ecological red-line policies in actual conservation efforts was also examined.ResultsThe results indicate that habitat quality among vegetation ecoregions is shaped by a complex interaction of geographical and human-induced factors, leading to notable spatiotemporal variations. From 2000 to 2020, the quality of habitats was significantly impacted by human activities, climate change, grazing intensity, and land-use changes. These effects were especially prominent during the period from 2005 to 2010.DiscussionThe changes in habitat quality on the Qinghai-Tibet Plateau are influenced by multiple driving factors, with significant differences in the drivers across various vegetation ecoregions. The ecological redline policy has played an important role in protecting the ecological environment in key areas, particularly in regions with high human intervention, where its effectiveness is more pronounced. In future ecological management, it is essential to strengthen conservation measures based on regional specificity. By comprehensively considering the impact of human activities and natural factors, developing more targeted management strategies is crucial for improving habitat quality.

The spatiotemporal evolution characteristics and influencing factors of habitat quality in the typical region of the Lunan Economic Belt: a case study of Donggang District, Rizhao.

Habitat quality is a key indicator for evaluating the biodiversity of a region. This study aims to assess the current status and characteristic changes of habitat quality in Donggang District, Rizhao while analyzing the potential factors influencing the quality of the habitat. The study employed the Integrated Valuation of Ecosystem Services and Tradeoffs Habitat Quality (InVEST-HQ) mode to assess the spatiotemporal variations in habitat quality in the Donggang District from 2008 to 2022. GeoDetector was utilized to investigate the impact of various factors on the spatial differentiation characteristics of habitat quality. The potential correlation between economic development and habitat quality was further explored using the Spearman correlation coefficient and Grayscale Association Analysis. The results reveal that habitat quality in Donggang District is highest in the east and lowest in the west, with significant correlations to land use and vegetation coverage. The study highlights a decline in habitat quality over the period, linked to rapid economic growth and industrial expansion. These insights are crucial for balancing urban biodiversity with economic development.

An overview of soil and plant assessment for predicting site quality and recovery strategies of one the largest tailings dam failures worldwide.

Brazil's Fundão dam collapse is one of the world's largest disasters of tailing dam failures. Previous research has evaluated toxic metals and non-metals (Cd, Cr, Ni, Pb, As, Hg) in the same soil samples used in this study, and results have indicated that only Fe and Mn concentrations increased above the original baseline (Melo et al., 2023). Consequently, the present study's focus has shifted towards assessing and integrating changes in soil quality regarding chemical fertility and morphological, physical, and mineralogical attributes in the floodplains post-dam collapse. Soil samples from 0 to 0.2 and 0.2-0.4m depths, and samples of Urochloa sp. were collected along ten transects, spanning 100km perpendicular to the Doce River channel. This sampling strategy targeted specific landscape positions including areas affected by deposited iron tailings (DIT), soil tailing mixture (STM), and control soil (CS) devoid of iron tailing interference. Results showed no discernible alterations in Ca, Mg, K, and P concentrations in Urochloa sp., and the most severe negative impacts observed regarded the replacement of kaolinitic pre-disaster matrix for hematitic matrix, reduction in organic carbon, and the prevalence of sand and silt particles. These factors collectively contributed to triggering: (i) decrease in chemical fertility and cation exchange capacity and (ii) significant decline in physical quality, evidenced by increased density and reduced total porosity and macroporosity. Addressing these adverse effects would require the augment of organic matter levels and offset the dominance of the hematitic matrix in the DIT. Furthermore, it is imperative to decompact the DIT by mechanized or plant cultivation means.

Magnetic field improves the quality of frozen tilapia fillets by decreasing the ice crystals during freezing process

SummaryIn this study, the alternating magnetic field (AMF) with frequency of 50, 100, 150, 200 and 250 Hz at magnetic field intensity of 5 mT was used to assist the freezing of tilapia fillets, with no magnetic field (NMF) as a control group. The evaluation of thawed tilapia fillets encompassed an assessment of freezing curve, texture, microstructure, moisture state and protein structure, followed by a subsequent analysis of their correlation. The findings showed that the application of a magnetic field during the freezing process yielded favourable outcomes in enhancing the overall quality of tilapia fillets. Among them, 200 Hz had the best effect. Under the condition, the frozen tilapia fillets assisted by magnetic field showed the shortest freezing time, the least decrease in hardness and elasticity and the best chewiness after thawing. The size of the ice crystals generated during freezing was small and uniform, and the fractal dimension of the frozen sections was the highest. Muscle tissue was the least damaged, which led to the improvement of its water‐holding capacity. Magnetic field‐assisted freezing was found to maintain the α‐helix and β‐sheet in the secondary structure of proteins. The correlation analysis showed that cohesion, elasticity, fractal dimension, FD, A2, A22 and β‐turn were closely related to the quality changes of tilapia fillets after magnetic field treatment.

Early Changes in Health-Related Quality of Life as a Biomarker of Survival in African Patients with HIV-Associated Kaposi Sarcoma.

Sub-Saharan Africa bears the largest public health burden of Kaposi sarcoma (KS), a leading cause of cancer mortality. Quality of life (QOL) assessments in cancer patients can provide information on prognosis beyond traditional biomarkers or biological measures. The prognostic value of QOL measures in patients with HIV-KS was evaluated. Prognostic associations of baseline QOL scores (by quartiles or thresholds for clinical importance) and changes in QOL scores (using minimum important difference) over the first 3 months of therapy were evaluated in 112 participants with HIV-KS randomised to receive ART, with or without chemotherapy. Cox's regression analysis assessed the prognostic contribution of QOL scores from the EORTC QLQ-C30 questionnaire. Survival curves were generated using the Kaplan-Meier method. Baseline QOL scores did not predict overall survival. The change in the 3-month QOL scores for the global health scale, fatigue, and pain domains was prognostic; the hazard ratios were 3.88 (95% CI 1.32-11.38, p = 0.01), 3.72 (95% CI 1.61-8.62, p = 0.00) and 5.96 (95% CI 2.46-14.43, p = 0.00), respectively. QOL assessments can provide useful prognostic information in patients with HIV-KS. Patients lacking meaningful improvement early into treatment represent a population at high risk of death.

ASYMMETRIC LEAVES1 promotes leaf hyponasty in Arabidopsis by light-mediated auxin signaling.

In plants, balancing growth and environmental responses is crucial for maximizing fitness. Close proximity among plants and canopy shade, which negatively impacts reproduction, elicits morphological adjustments such as hypocotyl growth and leaf hyponasty, mainly through changes in light quality and auxin levels. However, how auxin, synthesized from a shaded leaf blade, distally induces elongation of hypocotyl and petiole cells remains to be elucidated. We demonstrated that ASYMMETRIC LEAVES1 (AS1) promotes leaf hyponasty through the regulation of auxin biosynthesis, polar auxin transport, and auxin signaling genes in Arabidopsis (Arabidopsis thaliana). AS1 overexpression leads to elongation of the abaxial petiole cells with auxin accumulation in the petiole, resulting in hyponastic growth, which is abolished by the application of an auxin transport inhibitor to the leaf blade. In addition, the as1 mutant exhibits reduced hypocotyl growth under shade conditions. We observed that AS1 protein accumulates in the nucleus in response to shade or far-red light. Chromatin immunoprecipitation analysis identified the association of AS1 with the promoters of YUCCA8 (YUC8) and INDOLE-3-ACETIC ACID INDUCIBLE 19 (IAA19). In addition, AS1 forms complexes with PHYTOCHROME INTERACTING FACTORs in the nucleus and synergistically induces YUC8 and IAA19 expression. Our findings suggest that AS1 plays a crucial role in facilitating phenotypic plasticity to the surroundings by connecting light and phytohormone action.

Diversity of Butterflies in Guindy National Park-Butterfly Garden in Guindy Children’s Park

Guindy National Park is the only protected forest oasis holding good tropical dry evergreen forest vegetation sheltering many wild Fauna, and flora amidst the city. The literature survey provides a limited information analysis earlier before, on various aspects of Ecology & Conservation Management, Habitat analysis & assessment, distribution of Vegetation, diversity of fauna like Black buck, spotted deer, Birds, Jackal including lower vertebrates & Butterflies. Butterflies are the sensitive insects which react quickly to any kind of disturbances like changes in the habitat quality and environmental variation. Apart from pollinators they play a major key role in food chain, being prey for birds, reptiles, spiders and predatory insects. Many species of butterflies are strictly seasonal in their occurrence and prefer a particular set of habitats and host plants for their survival. Notably these biological indicators are slowly disappearing due to changes in land pattern and habitat as they are closely dependent on plants.

Diet Quality Changes in a 12-Week Web-Based Physical Activity Intervention without Explicit Dietary Guidance

Lifestyle habits seem interconnected and extant studies suggest that a lifestyle-related modification can impact other related behaviors. For instance, interventions targeting physical activity (PA) could potentially impact dietary patterns and quality. Therefore, we hypothesized that a web-based intervention to increase PA would lead to changes in diet quality without explicit dietary guidance. Our aim was to evaluate changes in diet quality, measured by the Healthy Eating Index 2020 (HEI-2020), following a 12-week web-based PA intervention in adults with obesity. The study consisted of secondary analysis of a 12-week pilot randomized controlled trial, wherein participants (N = 82) were randomized to the Physical Activity for The Heart (PATH) intervention group, which included workout videos and virtual coaching, or a wait-list control group. Diet quality was assessed at baseline and post-intervention using the HEI-2020 based on recalls collected through the Automated Self-Administered 24-h recall (ASA-24) system. Baseline characteristics were similar across groups. Both groups showed small improvements in HEI-2020 total scores after 12 wk (PATH: 65.11 vs. Control: 62.24). Stratification by moderate to vigorous physical activities increase (<60 min. vs. ≥60 min.) revealed greater improvements in specific HEI-2020 components in the ≥60 min group, though overall changes remained modest. The PA intervention led to small improvements in certain diet quality components, suggesting potential interconnectedness between PA and dietary habits. However, overall changes in HEI-2020 scores were modest. Future research with larger samples should explore the effects of PA intervention alone vs. combined with dietary guidance on diet quality in adults with obesity.

The state of rheological properties of blood in pregnant smokers with chronic nonspecific bronchial inflammation

Aim. To evaluate the effect of smoking on the blood rheology of pregnant smokers with chronic nonspecific bronchial inflammation. Materials and methods. The prospective study included 107 pregnant smoking patients and 136 non-smoking pregnant women who were observed in a polyclinic. The control group consisted of 42 non-smoking women without chronic diseases. The patients were examined according to the clinical guidelines for the treatment of chronic obstructive pulmonary disease. The speed and volume indicators of the function of external respiration, indicators of blood rheology were studied. The reliability of the results was assessed using the methods of parametric and nonparametric statistics. Before applying all statistical research methods, it was checked whether the sample obeys the Gaussian (normal) distribution law. A single-factor analysis of variance was used to determine whether there was a statistically significant difference between the averages of three or more independent groups. Results. Having refuted the null hypothesis about the absence of the effect of smoking on hemoglobin, using the Student's t-test method for dependent samples, it was established. Conclusion. The longer the period of tobacco use lasted, the more likely it was to develop changes in the viscosity qualities of blood, which undoubtedly affected the condition of patients and the fetus.

Influence of slow and rapid weight loss periods on physiological performance, mood state and sleep quality in male freestyle wrestlers: a study from Sichuan Province, China

ObjectiveThis study aims to investigate the changes in physiological performance, mental state and sleep quality during the weight reduction phase prior to competition in male freestyle wrestlers.MethodsThis study included 16 male freestyle wrestlers from Sichuan Province, China. Participants were evaluated at three time points: the first day of slow weight reduction (T1, March 26), the first day of rapid weight reduction (T2, April 26) and the day before the competition (T3, May 3), and measurements were taken for physiological performance, mood state and sleep quality.ResultsThe most relevant findings indicated the following: Morning heart rate, creatine kinase and fatigue scores increased by 12.6, 64.6, and 19.0%, respectively, from T1 to T2 (p &amp;lt; 0.05), and decreased by 14.1, 36.6, and 16.8%, respectively, from T2 to T3 (p &amp;lt; 0.05). Hemoglobin and testosterone levels decreased by 3.0 and 16.8%, respectively, from T1 to T3 (p &amp;lt; 0.05), and by 2.9 and 18.2%, respectively, from T2 to T3 (p &amp;lt; 0.05); The secondary findings revealed the following: The total mood disturbance scores decreased by 3.8% from T2 to T3 (p = 0.072), positive mood scores decreased by 9.0% from T1 to T2 (p = 0.090), the Pittsburgh Sleep Quality Index total scores increased by 14.4% from T1 to T2 (p = 0.323) and total work output and average power output decreased by 7.3 and 7.8%, respectively, from T1 to T3 (p = 0.067, p = 0.052); Regression analyses predicted negative mood (Y1 = 62.306–0.018 × maximum power output) and sleep quality (Y2 = 2.527 + 0.278 × Immunoglobulin G) during the weight reduction period.ConclusionThe combined slow and rapid weight reduction approach effectively minimized body fat in athletes with limited effect on their physiological performance and sleep quality. However, the effects were adverse on certain health variables and anaerobic power in Chinese male freestyle wrestlers. The identified correlations between negative mood and maximum power, and between sleep quality and immunoglobulin G, shed new light on factors influencing athletes’ well-being during weight reduction, and underscored the need for careful monitoring of physiological variables in future weight management strategies.

From Early Behavioral Intervention to School: A Systematic Evaluation of Parents' Perspectives on the Quality of the Autism Services During the Transition to Kindergarten.

Research emphasizes the importance of seamless transitions from Early Behavioral Intervention (EBI) to school-based services, but formal support during this critical period remains limited, leading to decreased parental satisfaction with autism services. This study aimed to systematically document parents' perception of the quality of services received during the transition from EBI to kindergarten, along with the predictors of this perception. The study adopted a prospective longitudinal design and relied on a validated evaluation framework, the Evaluation of the Trajectory in Autism for Parents (ETAP). ETAP allows to investigate five critical determinants (accessibility, continuity, validity, flexibility, empathy) of service quality, as rated by parents (N = 138 families), which were evaluated at three critical periods of the transition: end of EBI, beginning and end of first year of school. Quality ratings indicated generally positive perceptions but showed small to medium effect size decreases over time; validity had the largest decrease. Predictors of quality ratings and changes in ratings differed by phase of the transition and included child characteristics (gender, age, disabilities, challenging behavior), parent characteristics (maternal origin, fluency in the official language of the province, education level), and family characteristics (number of children). This study's comprehensive analysis of service quality determinants and possible risk and protective factors provides insights into improving support for families navigating the transition to school.Keywords: Autism, Early behavioral intervention, School transition, Parental perception, Service quality, Evaluation framework.

Preservative Effect of Alga Flour Extract on Frozen Horse Mackerel (Trachurus trachurus) Lipids.

The aim of this study was to investigate the preservative properties of alga Gelidium sp. flour when included in the glazing medium employed for the frozen storage (-18 °C) of horse mackerel (Trachurus trachurus). Different concentrations (low, medium, and high) of an aqueous extract were tested and compared to a control water-glazing condition. Quality changes (lipid oxidation and hydrolysis, fatty acid (FA) profile, and trimethylamine (TMA) formation) were determined after 3- and 6-month storage periods. A general quality loss (lipid oxidation with hydrolysis development and TMA formation) with the frozen storage period was detected in all samples. The presence of an alga flour (AF) extract in the glazing medium led to a lower (p < 0.05) TBARS and fluorescent compound formation and to higher (p < 0.05) polyene values in frozen fish. Furthermore, a preserving effect on free fatty acids was detected in AF-treated fish. On the contrary, the AF-glazing treatment did not affect (p > 0.05) the TMA formation and the total n3/total n6 FA ratio. In general, preservative effects were found to be higher in frozen fish corresponding to the medium concentration tested. Current results show the potential of Gelidium sp. flour as a natural source of preservative hydrophilic compounds for the quality enhancement of frozen horse mackerel.