Autochthonous cultures to improve the quality of PGI Castellano cheese: Impact on proteolysis, microstructure and texture during ripening.

The aim of this research was to find out the effect of different combinations of starter and non-starter cultures on the proteolysis of Castellano cheese during ripening. Four cheese batches were prepared, each containing autochthonous lactobacilli and or Leuconostoc, and were compared with each other and with a control batch, that used only a commercial starter. To achieve this, nitrogen fractions (pH 4.4-soluble nitrogen and 12 % trichloroacetic acid soluble nitrogen, polypeptide nitrogen and casein nitrogen), levels of free amino acids and biogenic amines were assessed. Texture and microstructure of cheeses were also evaluated. Significant differences in nitrogen fractions were observed between batches at different stages of ripening. The free amino acid content increased throughout the cheese ripening process, with a more significant increase occurring after the first 30 days. Cheeses containing non-starter lactic acid bacteria exhibited the highest values at the end of the ripening period. Among the main amino acids, GABA was particularly abundant, especially in three of the cheese batches at the end of ripening. The autochthonous lactic acid bacteria were previously selected as non-producers of biogenic amines and this resulted in the absence of these compounds in the cheeses. Analysis of the microstructure of the cheese reflected the impact of proteolysis. Additionally, the texture profile analysis demonstrated that the cheese's hardness intensified as the ripening period progressed. The inclusion of autochthonous non-starter lactic acid bacteria in Castellano cheese production accelerated the proteolysis process, increasing significantly the free amino acids levels and improving the sensory quality of the cheeses.

Temperature effects on plasmalogen profile and quality characteristics in Pacific oyster (Crassostrea gigas) during depuration.

The quality of Pacific oyster (Crassostrea gigas) can be affected by many factors during depuration, in which temperature is the major element. In this study, we aim to determine the quality and plasmalogen changes in C. gigas depurated at different temperatures. The quality was significantly affected by temperature, represented by varying survival rate, glycogen content, total antioxidant capacity, alkaline phosphatase activity between control and stressed groups. Targeted MS analysis demonstrated that plasmalogen profile was significantly changed during depuration with PUFA-containing plasmalogen species being most affected by temperature. Proteomics analysis and gene expression assay further verified that plasmalogen metabolism is regulated by temperature, specifically, the plasmalogen synthesis enzyme EPT1 was significantly downregulated by high temperature and four plasmalogen-related genes (GPDH, PEDS, Pex11, and PLD1) were transcriptionally regulated. The positive correlations between the plasmalogen level and quality characteristics suggested plasmalogen could be regarded as a quality indicator of oysters during depuration.

Explaining the improving effect of dough crumb-sheet composite rolling on fresh noodle quality: From microstructure and moisture distribution perspective.

A new technique known as dough crumb-sheet composite rolling (DC-SCR) was used to improve the quality of fresh noodles. However, there is a dearth of theoretical investigations into the optimal selection of specific parameters for this technology, and the underlying mechanisms are not fully understood. Therefore, the effects of dough crumb addition times in DC-SCR on the texture, cooking, and eating quality of fresh noodles were first studied. Then, the underlying regulation mechanism of DC-SCR technology on fresh noodles was analyzed in terms of moisture distribution and microstructure. The study demonstrated that the most significant enhancement in the quality of fresh noodles was achieved by adding dough crumbs six times. Compared with fresh noodles made without the addition of dough crumbs, the initial hardness and chewiness of fresh noodles made by adding six times of dough crumbs increased by 25.32% and 46.82%, respectively. In contrast, the cooking time and cooking loss were reduced by 28.45% and 29.69%, respectively. This quality improvement in fresh noodles made by DC-SCR came from the microstructural differences of the gluten network between the inner and outer layers of the dough sheet. A dense structure on the outside and a loose structure on the inside could endow the fresh noodles made by DC-SCR with higher hardness, a shortened cooking time, and less cooking loss. This study would provide a theoretical and experimental basis for creating high-quality fresh noodles.

The role of lncFABP4 in modulating adipogenic differentiation in buffalo intramuscular preadipocytes.

Intramuscular fat (IMF) is a crucial determinant of meat quality and is influenced by various regulatory factors. Despite the growing recognition of the important role of long noncoding RNAs (lncRNAs) in IMF deposition, the mechanisms underlying buffalo IMF deposition remain poorly understood. In this study, we identified and characterized a lncRNA, lncFABP4, which is transcribed from the antisense strand of fatty acid-binding protein 4 (FABP4). lncFABP4 inhibited cell proliferation in buffalo intramuscular preadipocytes. Moreover, lncFABP4 significantly increased intramuscular preadipocyte differentiation, as indicated by an increase in the expression of the adipogenic markers peroxisome proliferator-activated receptor gamma (PPARG), CCAAT enhancer binding protein alpha (C/EBPα), and FABP4. Mechanistically, lncFABP4 was found to have the potential to regulate downstream gene expression by participating in protein-protein interaction pathways. These findings contribute to further understanding of the intricate mechanisms through which lncRNAs modulate intramuscular adipogenesis in buffaloes.

Effect of defatted Lagenaria siceraria (Molina) Standley seed flour as a fat replacer on physicochemical, technological, and sensory properties of beef patty.

Defatted Lagenaria siceraria seed flour (DLSSF) was obtained from defatted seed cake, dried, and ground through a sieve of 500 µm and characterized. A 2 × 4 factorial design (two flour hydration rates and four fat substitution rates) was used to produce a low-fat beef patty by replacing fat with DLSSF. Beef kidney fat was used to formulate the control sample. Chemical, physical, technological, sensory, and nutritional characteristics of low-fat beef patties manufactured were evaluated. DLSSF contains mainly protein. As fat replacers, DLSSF induces a significant increase in the pH of the raw and cooked patty, the moisture and protein contents, the cooking yield, the cohesion, chewiness, springiness, and lightness of the cooked beef patty with fat substitution rate. There is a decrease in fat content, total calories, water retention capacity, hardness, and redness of the cooked patty with a fat substitution rate. From the sensory analysis, the substitution of fat improves the acceptability of samples. Based on the overall parameters analyzed, DLSSF containing 60% water can be used to produce low-fat beef patty by replacing fat at 100%. From these results, hydrated DLSSF could be an effective method to solve the problems of noncommunicable diseases related to animal fat consumption.

Tipologías de padres y madres según sus prácticas parentales de alimentación: un análisis de perfiles latentes en familias con doble ingreso e hijos adolescentes / Typologies of fathers and mothers according to their parental feeding practices: a latent profi le analysis in dual-income families with adolescent children

Introducción: esta investigación buscó identificar perfiles de padres y madres según sus prácticas parentales de alimentación (PPA) (monitoreo, restricción, modelo y control infantil) y determinar si los perfiles difieren según su satisfacción con la alimentación (SWFoL), interfaz trabajo-familia, calidad de la dieta de padres y madres e hijos/as adolescentes, tipo de trabajo y características sociodemográficas (nivel socioeconómico, género y edad). Método: la muestra fue de 430 familias biparentales con doble ingreso e hijos/as adolescentes de Santiago, Chile. Se utilizaron el Cuestionario Comprensivo de Prácticas Parentales de Alimentación, la Escala de Satisfacción con la Alimentación (SWFoL), el Índice de Alimentación Saludable Adaptado (IAS) y la Escala de Interfaz trabajo-familia (conflicto trabajo y familia y enriquecimiento trabajo y familia). Resultados: el análisis de perfiles latentes mostró cinco perfiles de padres y madres: a) madres y padres con alto control y restricción (32,1 %); b) madres y padres con alto control y muy bajo monitoreo, restricción y modelo (29,5 %); c) madres con alto monitoreo y padres con bajo control y restricción (18,8 %); d) madres y padres con alto monitoreo (14,9 %); y e) madres y padres con alta restricción y modelo (4,7 %). Conclusión: los perfiles difirieron en los puntajes de SWFoL de padres y madres, conflicto familia-trabajo del padre, enriquecimiento trabajo y familia del padre, calidad de la dieta de los tres miembros de la familia y en el índice de masa corporal de las madres. Los resultados sugieren que los padres y las madres utilizan diferentes combinaciones de PPA según las características de sus familias y lugares de trabajo.(AU)

Background: this research was designed to identifying profiles of parents according to their food parenting practices (FPFP) (monitoring, restriction, modeling and child control) and to determine whether the profiles differed according to their satisfaction with food-related life (SWFoL),work-family interface, diet quality of parents and adolescent type of work and sociodemographic characteristics (socioeconomic level, genderand age). Methods: the sample consisted of 430 two-parent dual-income families with adolescent in Santiago, Chile. The Comprehensive questionnaire of Parental Eating Practices, Satisfaction with Food-related Life scale (SWFoL), Adapted Healthy Eating Index (AHEI) and Work-Family Interface Scale (work-family conflict and work-family enrichment) were used. Results: latent profile analysis showed five profiles of fathers and mothers: a) mothers and fathers with high control and restraint (32.1 %); b) mothers and fathers with high control and very low monitoring, restriction and modeling (29.5 %); c) mothers with high monitoring and fathers with low control and restriction (18.8 %); d) mothers and fathers with high monitoring (14.9 %); and e) mothers and fathers with high restraint and modeling (4.7 %). Conclusions: the profiles differed in fathers’ and mothers’ SWFoL scores, fathers’ work-family conflict, fathers’ work-family enrichment, diet quality of all three family members, and mothers’ body mass index. The results suggest that fathers and mothers use different combinations of FPP according to the characteristics of their families and workplaces.(AU)

Recent Advances and Future Perspectives in the E-Nose Technologies Addressed to the Wine Industry.

Electronic nose devices stand out as pioneering innovations in contemporary technological research, addressing the arduous challenge of replicating the complex sense of smell found in humans. Currently, sensor instruments find application in a variety of fields, including environmental, (bio)medical, food, pharmaceutical, and materials production. Particularly the latter, has seen a significant increase in the adoption of technological tools to assess food quality, gradually supplanting human panelists and thus reshaping the entire quality control paradigm in the sector. This process is happening even more rapidly in the world of wine, where olfactory sensory analysis has always played a central role in attributing certain qualities to a wine. In this review, conducted using sources such as PubMed, Science Direct, and Web of Science, we examined papers published between January 2015 and January 2024. The aim was to explore prevailing trends in the use of human panels and sensory tools (such as the E-nose) in the wine industry. The focus was on the evaluation of wine quality attributes by paying specific attention to geographical origin, sensory defects, and monitoring of production trends. Analyzed results show that the application of E-nose-type sensors performs satisfactorily in that trajectory. Nevertheless, the integration of this type of analysis with more classical methods, such as the trained sensory panel test and with the application of destructive instrument volatile compound (VOC) detection (e.g., gas chromatography), still seems necessary to better explore and investigate the aromatic characteristics of wines.

What Is Quality Food? The Opinion of Key of the Brazilian Food System.

The aim of the study was to explore the concept of quality food in the opinion of key informants of the food system. This qualitative research included 208 key informants related to the food supply for Brazilian public food services. The participants were grouped into three groups according to their participation in the food system: 1. Food production; 2. Management and marketing; 3. Meal's production process. Key informants answered the following question: "In your opinion, what is quality food?". The answers were analysed through qualitative content analysis. The data analysis resulted in 52 codes grouped into eight categories, expressing the opinion of the study participants about what quality food is: nutritional, sustainable, sensory, hygienic-sanitary, care, regulatory, dependability and symbolic. Nutritional and sustainable dimensions were predominantly considered. The activities carried out in the food system seem to influence the opinion on food quality. The groups linked to food production put more emphasis on the sustainable dimension, followed by the nutritional dimension, while the groups linked to management and marketing and to the meals production process put more emphasis on the nutritional and sensory dimensions. These differences may indicate a difficulty in the transition towards a more sustainable and healthy food system.

Comprehensive fluorescence profiles of contamination-prone foods applied to the design of microcontact-printed in situ functional oligonucleotide sensors.

With both foodborne illness and food spoilage detrimentally impacting human health and the economy, there is growing interest in the development of in situ sensors that offer real-time monitoring of food quality within enclosed food packages. While oligonucleotide-based fluorescent sensors have illustrated significant promise, the development of such on-food sensors requires consideration towards sensing-relevant fluorescence properties of target food products-information that has not yet been reported. To address this need, comprehensive fluorescence profiles for various contamination-prone food products are established in this study across several wavelengths and timepoints. The intensity of these food backgrounds is further contextualized to biomolecule-mediated sensing using overlaid fluorescent oligonucleotide arrays, which offer perspective towards the viability of distinct wavelengths and fluorophores for in situ food monitoring. Results show that biosensing in the Cyanine3 range is optimal for all tested foods, with the Cyanine5 range offering comparable performance with meat products specifically. Moreover, recognizing that mass fabrication of on-food sensors requires rapid and simple deposition of sensing agents onto packaging substrates, RNA-cleaving fluorescent nucleic acid probes are successfully deposited via microcontact printing for the first time. Direct incorporation onto food packaging yields cost-effective sensors with performance comparable to ones produced using conventional deposition strategies.

Effect of ultrasonic treatment during fermentation on the quality of fortified sweet wine.

The present study aimed to investigate the potential of ultrasonic treatment during fermentation for enhancing the quality of fortified wines with varying time and power settings. Chemical analysis and sensory evaluation were conducted to assess the impact of ultrasonic treatment on wine quality. Results showed that ultrasonic treatment could increase total anthocyanin and total phenol content, reduce anthocyanin degradation rate, and improve color stability. Moreover, ethyl carbamate content was lower in the ultrasonic group after aging compared to non-ultrasonic group. A combination of 200 W for 20 min resulted in higher sensory scores and more coordinated taste, while a combination of 400 W for 40 min produced higher levels of volatile compounds (21860.12 µg/L) leading to a richer and more elegant aroma. Therefore, ultrasound can be used as a potential technology to improve the quality of wine.

Application of surface-modified functional packaging in food storage: A comprehensive review.

Innovations in food packaging systems could meet the evolving needs of the market; emerging concepts of non-migrating technologies reduce the negative migration of preservatives from packaging materials, extend shelf life, and improve food quality and safety. Non-migratory packaging activates the surface of inert materials through pretreatment to generate different active groups. The preservative is covalently grafted with the resin of the pretreated packaging substrate through the graft polymerization of the monomer and the coupling reaction of the polymer chain. The covalent link not only provides the required surface properties of the material for a long time but also retains the inherent properties of the polymer. This technique is applied to the processing for durable, stable, and easily controllable packaging widely. This article reviews the principles of various techniques for packaging materials, surface graft modification, and performance characterization of materials after grafting modification. Potential applications in the food industry and future research trends are also discussed.

Quantum dots as advanced nanomaterials for food quality and safety applications: A comprehensive review and future perspectives.

The importance of food quality and safety lies in ensuring the best product quality to meet consumer demands and public health. Advanced technologies play a crucial role in minimizing the risk of foodborne illnesses, contamination, drug residue, and other potential hazards in food. Significant materials and technological advancements have been made throughout the food supply chain. Among them, quantum dots (QDs), as a class of advanced nanomaterials with unique physicochemical properties, are progressively demonstrating their value in the field of food quality and safety. This review aims to explore cutting-edge research on the different applications of QDs in food quality and safety, including encapsulation of bioactive compounds, detection of food analytes, food preservation and packaging, and intelligent food freshness indicators. Moreover, the modification strategies and potential toxicities of diverse QDs are outlined, which can affect performance and hinder applications in the food industry. The findings suggested that QDs are mainly used in analyte detection and active/intelligent food packaging. Various food analytes can be detected using QD-based sensors, including heavy metal ions, pesticides, antibiotics, microorganisms, additives, and functional components. Moreover, QD incorporation aided in improving the antibacterial and antioxidant activities of film/coatings, resulting in extended shelf life for packaged food. Finally, the perspectives and critical challenges for the productivity, toxicity, and practical application of QDs are also summarized. By consolidating these essential aspects into this review, the way for developing high-performance QD-based nanomaterials is presented for researchers and food technologists to better capitalize upon this technology in food applications.

Improvement on wheat bread quality by in situ produced dextran-A comprehensive review from the viewpoint of starch and gluten.

Deterioration of bread quality, characterized by the staling of bread crumb, the softening of bread crust and the loss of aroma, has caused a huge food waste and economic loss, which is a bottleneck restriction to the development of the breadmaking industry. Various bread improvers have been widely used to alleviate the issue. However, it is noteworthy that the sourdough technology has emerged as a pivotal factor in this regard. In sourdough, the metabolic breakdown of carbohydrates, proteins, and lipids leads to the production of exopolysaccharides, organic acids, aroma compounds, or prebiotics, which contributes to the preeminent ability of sourdough to enhance bread attributes. Moreover, sourdough exhibits a "green-label" feature, which satisfies the consumers' increasing demand for additive-free food products. In the past two decades, there has been a significant focus on sourdough with in situ produced dextran due to its exceptional performance. In this review, the behaviors of bread crucial compositions (i.e., starch and gluten) during dough mixing, proofing, baking and bread storing, as well as alterations induced by the acidic environment and the presence of dextran are systemically summarized. From the viewpoint of starch and gluten, results obtained confirm the synergistic amelioration on bread quality by the coadministration of acidity and dextran, and also highlight the central role of acidification. This review contributes to establishing a theoretical foundation for more effectively enhancing the quality of wheat breads through the application of in situ produced dextran.

The Meat Standards Australia carcass grading site affects assessment of marbling and prediction of meat-eating quality in growing European beef cattle.

The lack of consumer feedback on beef eating quality contributes to reduced beef consumption in Europe. The Meat Standards Australia (MSA) grading scheme can assess the palatability of beef carcasses usually graded at the 10th thoracic vertebrae. However, the European beef industry relies on late-maturing breeds usually cut at the 5th vertebrae due to commercial reasons. Data from 55 young bulls and heifers of late-maturing breeds were collected in an Italian slaughterhouse following the MSA guidelines at both carcass grading sites and sides. Intramuscular fat levels were assessed through two scores and used with other variables to feed the MSA model, which predicts the MSA index, the meat-eating quality scores (MQ4) for 5 muscles and for each carcass grading site × side combination. The scores were analyzed using a mixed linear model. A correlation analysis was conducted to predict the variables measured at the 10th site using their correspondent at the 5th carcass grading site. A stepwise regression was conducted to understand the weight of each measured variable on marbling and MQ4 scores measured both at 5th and 10th carcass grading sites. Results showed significantly higher value for the studied traits at the 5th carcass grading site, while carcass side had no significant impact. The equations had high predictive capability and MSA marbling score played a key role in explaining the variability across carcass grading sites. The differences in marbling and MQ4 scores between the carcass grading sites suggest considering this factor if the MSA grading system will be applied to Europe.

Effect of pulsed electric field (PEF) on NaCl diffusion in beef and consequence on meat quality.

The impact of various field strength (2, 3, 4 kV/cm) and treatment time (60s and 90s) combinations on NaCl content and diffusion coefficient of beef were evaluated in the current study. Weight change, water content, water holding capacity, and texture of beef after brining were also explored. The results demonstrated pulsed electric field (PEF) pre-treatment significantly increased NaCl uptake when the brining time was 150 min (P < 0.05). The maximum NaCl content increased by 19.50% and the diffusion coefficient increased by 58.50%. Relatively mild PEF (60s) could improve beef qualities, but longer treatment time (90s) was detrimental to these qualities. Meanwhile, more complete myofibrillar structure and lower lipid oxidation extent were observed in the samples treated by PEF, contributing to the higher a* values. In conclusion, short processing time (60s) and high field strength (4 kV/cm) treatment is a potential strategy for meat brining acceleration and quality improvement in practical industrial production.

An Evaluation of the Physicochemical Properties of Sesame Paste Produced by Ball Milling Compared against Conventional Colloid Milling.

The physicochemical characteristics and general food quality were greatly impacted by milling. In order to investigate the effect of milling technique for physicochemical properties of sesame paste of sesame paste, samples were prepared using ball mill and colloid mill by varying grinding times. The samples prepared by ball milling had the higher moisture contents (0.07% - 0.14%) than colloid milling (p < 0.05), except for colloid milling for one cycle (0.11%). The particle size curves showed the multimodal distributions. Compared to colloid milled samples, ball milled samples have smaller particle sizes and more uniform particle distribution. The L* values of samples prepared by ball milling were higher than colloid milling. The ball mill produced sesame paste with a wider range of hardness and silkier texture, and the samples made by ball milling for 30 min had the highest hardness. And the hardness of both CMS and BMS showed a decreasing trend with increasing grinding time. During ball milling, high-speed cutting and collision caused breakage of disulfide bonds, and the sesame proteins were decomposed to their subunits. In conclusions, ball milling may be an alternative and promising process for the preparation of sesame paste.

Elucidating the influence and mechanism of different phenols on the properties, food quality and function of maize starch.

This study discusses interaction differences between three phenols (protocatechuic acid, naringin and tannic acid) and starch helix, investigates influences of phenols at different doses on properties of maize starch, and further determines their effects on quality and function of maize-starchy foods. Simulated results indicate variations of phenolic structure (phenolic hydroxyl group amount, glycoside structure and steric hindrance) and dose induce phenols form different complexes with starch helix. Formation of different starch-phenols complexes alters gelatinization (1.65-5.63 J/g), pasting form, water binding capacity (8.83-12.69 g/g) and particle size distribution of starch. Meanwhile, differences in starch-phenols complexes are reflected in fingerprint area (R1045/1022: 0.920 to 1.047), crystallinity (8.3% to 17.0%), rheology and gel structure of starch. Additionally, phenols change texture and color of cold maize cake, giving them different antioxidant capacity and lower digestibility. Findings are beneficial for understanding interaction between starch and different phenols and their potential application.

Relación entre el conocimiento de los padres del etiquetado nutricional y el consumo de alimentos ultraprocesados con el estado nutricional de niños de 6 a 12 años / Relationship between parents' knowledge of nutritional labeling and the consumption of ultra-processed foods with the nutritional status of children aged 6 to 12 years

Fundamentos: La prevalencia del exceso de peso infantil ha ido incrementando cada año, lo cual está relacionado con diversos factores entre ellos se encuentra consumo de alimentos ultraprocesados. El objetivo fue determinar la relación existente entre el conocimiento de los padres acerca del etiquetado de información nutricional (etiquetado nutricional y al etiquetado frontal) y el consumo de alimentos ultraprocesados con el estado nutricional de escolares de 6 a 12 años. Métodos: Se realizó un estudio cuantitativo, observacional y transversal, en una muestra total de 255 padres y escolares. Se aplicaron dos cuestionarios para determinar el conocimiento del etiquetado nutricional de los padres y un cuestionario de frecuencia de consumo de alimentos ultraprocesados. Se hicieron mediciones antropométricas a los escolares. Resultados: Del total de los padres que participaron el 65,10% tenía un nivel de conocimiento bajo del etiquetado de información nutricional y el 80% un nivel de conocimiento deficiente del etiquetado frontal. Respecto a los escolares el 35,29% tuvieron un alto consumo de alimentos ultraprocesados, en el IMC se encontró que un 60,78% presentaban exceso de peso; acerca del perímetro abdominal (PAB) un 39,61% tenían un alto o muy alto riesgo cardio metabólico. Además, se encontró una relación significativa entre el conocimiento del etiquetado de información nutricional y el PAB (p<0,05), también se encontró una significancia estadística (p<0,01) entre el IMC y el PAB. Conclusiones: Existe relación significativa entre el conocimiento de etiquetado nutricional de los padres y el consumo de alimentos ultraprocesados sobre el estado nutricional de los escolares de 6 a 12 años. (AU)

Background: The prevalence of childhood excess weight has been increasing each year, which is related to various factors, including the consumption of ultra-processed foods. The objective was to determine the relationship between parents' knowledge about nutritional information labeling (nutritional labeling and front labeling) and the consumption of ultra-processed foods with the nutritional status of schoolchildren aged 6 to 12 years. Methods: A quantitative, observational and cross-sectional study was carried out in a total sample of 255 parents and schoolchildren. Two questionnaires were applied to determine parents' knowledge of nutritional labeling and a frequency of consumption of ultra-processed foods questionnaire. Anthropometric measurements were made to the schoolchildren. Results: Of the total number of parents who participated, 65.10% had a low level of knowledge of nutritional information labeling and 80% had a poor level of knowledge of front labeling. Regarding schoolchildren, 35.29% had a high consumption of ultra-processed foods, in the BMI it was found that 60.78% were overweight; Regarding PAB, 39.61% had a high or very high cardio-metabolic risk. In addition, a significant relationship was found between knowledge of nutritional information labeling and PAB (p<0.05), and a statistical significance (p<0.01) was also found between BMI and PAB. Conclusions: There is a significant relationship between parents' knowledge of nutritional labeling and the consumption of ultra-processed foods on the nutritional status of schoolchildren aged 6 to 12 years. (AU)

How do small dams alter river food webs? A food quality perspective along the aquatic food web continuum.

Damming of rivers poses a significant threat to freshwater ecosystems. Previous studies about the impact of damming on river ecosystems have mostly focused on large dams, with the impact of small dams largely unknown. Further, while the impacts of dams on aquatic communities have been widely studied, the effect on energy flow across river food webs remains unclear. In recent years, long-chain polyunsaturated fatty acid analysis (LC-PUFA) has emerged as a promising technique for assessing food quality and trophic interactions. In this study, LC-PUFA was applied to explore the nutritional effects of small dams on river food webs. A field investigation was conducted at upstream and downstream areas of three small dams in the headwaters of Dongjiang River, China, to evaluate the impact of small dams on the nutritional quality of basal food sources, and their consequent impacts on aquatic consumers and trophic links. Basal food sources (i.e., submerged leaves, macrophytes and periphyton) and aquatic consumers (i.e., macroinvertebrates and fish) were collected, and their fatty acid (FA) composition was measured. Our results showed that periphyton, rather than submerged leaves and macrophytes, was the primary high-quality food source for aquatic consumers, providing them with LC-PUFA, irrespective of whether sites were upstream or downstream. Damming the streams induced changes in aqueous nutrient concentrations (TP, PO4-P, DIN, and TN) from upstream to downstream of the dams, leading to significant variation in periphyton FA content. Compared with periphyton collected at downstream sites, periphyton at upstream sites contained higher LC-PUFA, but lower short-chain PUFA. Differences in periphyton LC-PUFA between the upstream and downstream areas of dams were reflected in the FA profiles of invertebrate grazers and filterers, and further transferred to fish. Furthermore, decreased periphyton nutritional quality at the downstream of the dams was one of the reasons for the simplification of stream food webs. Our results indicated that small dams negatively affected food webs, emphasizing the importance of high-quality food sources for stream ecosystems. We suggest that the trophic integrity of river food webs hinges on the dietary availability of periphyton supplying physiologically highly required nutrients for consumers and must thus not be compromised by damming of streams or other alterations.

Combining thermosonication microstress and pineapple peel extract addition to achieve quality and post-acidification control in yogurt fermentation.

This work investigated the effects of the combined use of thermosonication-preconditioned lactic acid bacteria (LAB) with the addition of ultrasound-assisted pineapple peel extracts (UU group) on the post-acidification potential, physicochemical and functional qualities of yogurt products, aimed at achieving prolonged preservation and enhancing functional attributes. Accordingly, the physical-chemical features, adhesion properties, and sensory profiles, acidification kinetics, the contents of major organic acids, and antioxidant activities of the differentially processed yogurts during refrigeration were characterized. Following a 14-day chilled storage process, UU group exhibited acidity levels of 0.5-2 oT lower than the control group and a higher lactose content of 0.07 mg/ml as well as unmodified adhesion potential, indicating that the proposed combination method efficiently inhibited post-acidification and delayed lactose metabolism without leading to significant impairment of the probiotic properties. The results of physicochemical analysis showed no significant changes in viscosity, hardness, and color of yogurt. Furthermore, the total phenolic content of UU-treated samples was 98 µg/mL, 1.78 times higher than that of the control, corresponding with the significantly lower IC50 values of DPPH and ABTS radical scavenging activities of the UU group than those of the control group. Observations by fluorescence inverted microscopy demonstrated the obvious adhesion phenomenon with no significant difference found among differentially prepared yogurts. The results of targeted metabolomics indicated the proposed combination strategy significantly modified the microbial metabolism, leading to the delayed utilization of lactose and the inhibited conversion into glucose during post-fermentation, as well as the decreased lactic acid production and a notable shift towards the formation of relatively weak acids such as succinic acid and citric acid. This study confirmed the feasibility of thermosonication-preconditioned LAB inocula, in combination with the use of natural active components from fruit processing byproducts, to alleviate post-acidification in yogurt and to enhance its antioxidant activities as well as simultaneously maintaining sensory features.