Feasibility of Using a Cheap Colour Sensor to Detect Blends of Vegetable Oils in Avocado Oil.

This proof-of-concept study explored the use of an RGB colour sensor to identify different blends of vegetable oils in avocado oil. The main aim of this work was to distinguish avocado oil from its blends with canola, sunflower, corn, olive, and soybean oils. The study involved RGB measurements conducted using two different light sources: UV (395 nm) and white light. Classification methods, such as Linear Discriminant Analysis (LDA) and Least Squares Support Vector Machine (LS-SVM), were employed for detecting the blends. The LS-SVM model exhibited superior classification performance under white light, with an accuracy exceeding 90%, thus demonstrating a robust prediction capability without evidence of random adjustments. A quantitative approach was followed as well, employing Multiple Linear Regression (MLR) and LS-SVM, for the quantification of each vegetable oil in the blends. The LS-SVM model consistently achieved good performance (R2 > 0.9) in all examined cases, both for internal and external validation. Additionally, under white light, LS-SVM models yielded root mean square errors (RMSE) between 1.17-3.07%, indicating a high accuracy in blend prediction. The method proved to be rapid and cost-effective, without the necessity of any sample pretreatment. These findings highlight the feasibility of a cost-effective colour sensor in identifying avocado oil blended with other oils, such as canola, sunflower, corn, olive, and soybean oils, suggesting its potential as a low-cost and efficient alternative for on-site oil analysis.

Soybean Plants Exposed to Low Concentrations of Potassium Iodide Have Better Tolerance to Water Deficit through the Antioxidant Enzymatic System and Photosynthesis Modulation.

Water deficit inhibits plant growth by affecting several physiological processes, which leads to the overproduction of reactive oxygen species (ROS) that may cause oxidative stress. In this regard, iodine (I) is already known to possibly enhance the antioxidant defense system of plants and promote photosynthetic improvements under adverse conditions. However, its direct effect on water deficit responses has not yet been demonstrated. To verify the efficiency of I concerning plant tolerance to water deficit, we exposed soybean plants to different concentrations of potassium iodide (KI) fed to pots with a nutrient solution and subsequently submitted them to water deficit. A decline in biomass accumulation was observed in plants under water deficit, while exposure to KI (10 and 20 µmol L-1) increased plant biomass by an average of 40%. Furthermore, exposure to KI concentrations of up to 20 µM improved gas exchange (~71%) and reduced lipid peroxidation. This is related to the higher enzymatic antioxidant activities found at 10 and 20 µM KI concentrations. However, when soybean plants were properly irrigated, KI concentrations greater than 10 µM promoted negative changes in photosynthetic efficiency, as well as in biomass accumulation and partition. In sum, exposure of soybean plants to 10 µM KI improved tolerance to water deficit, and up to this concentration, there is no evidence of phytotoxicity in plants grown under adequate irrigation.

Lab-made 3D printed electrochemical sensors coupled with chemometrics for Brazilian coffee authentication.

Analytical assurance of coffees' geographical indication (GI) authenticity is essential for producers and consumers. In this way, chemometric methods, electrochemical techniques, and 3D printed sensors become attractive to assure the coffee's quality. These sensors are low-cost, fast, and simple, with the possibility of miniaturization and portability. Therefore, 3D printed electrodes with chemometrics were used to classify-three Brazilian coffees from regions with GI. Further, Au/Gpt-PLA electrodes with partial least squares regression were used to detect the blending of GI coffee with traditional coffee. Soft independent modelling of class analogies coupled with cyclic voltammetry had the best performance, with 91-95% accuracy, specificity of 94-100%, and 80-83% sensitivity. Furthermore, the calibration models detected and quantified traditional coffee in all three coffees from regions with GI. The detection limits ranged from 1.4 to 10% (w/w), and quantification 4.6-32%, depending on the specific coffee.

Development and Application of an SPR Nanobiosensor Based on AuNPs for the Detection of SARS-CoV-2 on Food Surfaces.

A new transmission route of SARS-CoV-2 through food was recently considered by the World Health Organization (WHO), and, given the pandemic scenario, the search for fast, sensitive, and low-cost methods is necessary. Biosensors have become a viable alternative for large-scale testing because they overcome the limitations of standard techniques. Herein, we investigated the ability of gold spherical nanoparticles (AuNPs) functionalized with oligonucleotides to detect SARS-CoV-2 and demonstrated their potential to be used as plasmonic nanobiosensors. The loop-mediated isothermal amplification (LAMP) technique was used to amplify the viral genetic material from the raw virus-containing solution without any preparation. The detection of virus presence or absence was performed by ultraviolet-visible (UV-Vis) absorption spectroscopy, by monitoring the absorption band of the surface plasmonic resonance (SPR) of the AuNPs. The displacement of the peak by 525 nm from the functionalized AuNPs indicated the absence of the virus (particular region of gold). On the other hand, the region ~300 nm indicated the presence of the virus when RNA bound to the functionalized AuNPs. The nanobiosensor system was designed to detect a region of the N gene in a dynamic concentration range from 0.1 to 50 × 103 ng·mL-1 with a limit of detection (LOD) of 1 ng·mL-1 (2.7 × 103 copy per µL), indicating excellent sensitivity. The nanobiosensor was applied to detect the SARS-CoV-2 virus on the surfaces of vegetables and showed 100% accuracy compared to the standard quantitative reverse transcription polymerase chain reaction (RT-qPCR) technique. Therefore, the nanobiosensor is sensitive, selective, and simple, providing a viable alternative for the rapid detection of SARS-CoV-2 in ready-to-eat vegetables.

Multivariate Nature of Fish Freshness Evaluation by Consumers.

The aim of the present study was to evaluate the sensory acceptability limit of refrigerated fish through a multivariate approach, involving classic physicochemical and bacteriological indicators and considering different consumer profiles. The results of the survival analysis demonstrated that, in general, consumers still considered the fish to be suitable for purchase (4.128 days of storage), despite being microbiologically unsuitable for consumption. However, the subsequent division of consumers into clusters indicated that women and individuals with high income and education levels tend to reject fish with few days of storage (3.650 days), mainly due to discoloration, despite still being microbiologically suitable for consumption. Thus, these segments present a safer behavior regarding the purchase of fresh fish. The influence of different frequencies of fish consumption and age of consumers on the assessment of fish freshness was not clarified. The responsibility for ensuring safe and healthy products at the point of sale must lie with the producers and distributors. However, improving consumers' ability to make good choices when buying fresh fish would bring social and economic benefits related to public health and to the seafood industry, because it would enable them to make relevant claims and demand their rights.

A single screen-printed electrode in tandem with chemometric tools for the forensic differentiation of Brazilian beers.

In the present study a single screen-printed carbon electrode (SPCE) and chemometric techniques were utilized for forensic differentiation of Brazilian American lager beers. To differentiate Brazilian beers at the manufacturer and brand level, the classification techniques: soft independent modeling of class analogy (SIMCA), partial least squares regression discriminant analysis (PLS-DA), and support vector machines discriminant analysis (SVM-DA) were tested. PLS-DA model presented an inconclusive assignment ratio of 20%. On the other hand, SIMCA models had a 0 inconclusive rate but an sensitivity close to 85%. While the non-linear technique (SVM-DA) showed an accuracy of 98%, with 95% sensitivity and 98% specificity. The SPCE-SVM-DA technique was then used to distinguish at brand level two highly frauded beers. The SPCE coupled with SVM-DA performed with an accuracy of 97% for the classification of both brands. Therefore, the proposed electrochemicalsensor configuration has been deemed an appropriate tool for discrimination of American lager beers according to their producer and brands.

Pequi (Caryocar brasiliense) Waste Extract as a Synergistic Agent in the Microbial and Physicochemical Preservation of Low-Sodium Raw Goat Cheese.

The growth of spoilage and pathogenic bacteria during storage represents significant losses in marketing raw milk cheeses. Thus, reducing NaCl in these products is challenging, as sodium has a critical antimicrobial role. Despite advances in non-thermal technologies, the short shelf life still limits the availability of raw goat cheese. Thus, combined preservation methods can be promising because their synergies can extend shelf life more effectively. In this context, Principal Component Analysis (PCA) was applied to variables to investigate the effect of pequi waste extract (PWE), a native Brazilian fruit, combined with UV-C radiation (CEU) and vacuum packaging (CEV) on the preservation of low-sodium raw goat cheese. CEV samples had lower loadings for Staphylococcus subsp. and Enterobacteriaceae than other treatments in PC2, having a count's reduction up to 3-fold (P < 0.05) compared to vacuum alone. In contrast, CEU showed an increase of up to 1.2-fold on staphylococcal count compared to UV-C alone. Still, the addition of PWE to UV-C-treated cheeses resulted in 8.5% protein loss. Furthermore, PWE, especially in CEV, delayed post-acidification during storage. It made CEV up to 4.5 and 1.6-fold more stable for color and texture, respectively than vacuum alone. These data strongly suggest that PWE may be a novel and promising synergistic agent in the microbial and physicochemical preservation of low-sodium raw milk cheese when combined with the vacuum.

A Review on the Obtaining of Functional Beers by Addition of Non-Cereal Adjuncts Rich in Antioxidant Compounds.

Beer is one of the oldest and most consumed beverages worldwide, and recent trends point to increased consumption of functional beers. However, there is a lack in the scientific literature on the effects of adding functional adjuncts in distinct steps of the manufacturing process and its implications on the final physicochemical and sensorial profile. Therefore, the present review analyzes the ingredients used and their insertion stage to achieve a functional beer with bioactive compounds, higher antioxidant activity, and improved sensory characteristics. The addition of fruits, herbal extracts, plants, and mushrooms in beers was documented. Furthermore, adjuncts were successfully added in wort boiling, fermentation, maturation, and packaging. The wort boiling step stands out among these four due to the superior extraction of phenolic compounds from the added adjuncts. On the other hand, adjunct addition in the maturation step induced low increases in antioxidant and phenolic content of the respective enriched beers. Fruits represented the majority of adopted adjuncts among the studies evaluated. Furthermore, the addition of fruits represented a positive increment in the beer's volatile profile and an increase in sensory acceptability. A gap in the literature was found regarding the analysis of phenolic compounds with appropriate techniques such as HPLC-MS. Furthermore, there is a need to study the bioavailability of the incorporated bioactive compounds to prove the health claims inferred about these beers. In conclusion, functional beers are a little-explored relevant field, with potential for new studies.

Optimization of UV-C light and lactic acid combined treatment in decontamination of sliced Brazilian dry-cured loin: Salmonella Typhimurium inactivation and physicochemical quality.

This study aimed to test the effect of UV-C light (0.01-0.64 J/cm2) (UV) and lactic acid (0.1-12.9%) (LA) combined treatment on sliced Brazilian dry-cured loin (Socol, BDL) for (i) Salmonella Typhimurium reduction, (ii) physicochemical changes (color (a*, cured color, and ΔE), protein and lipid oxidation) and (iii) optimization using response surface methodology (RSM). Linear inactivation rate was achieved and UV was 2-fold more efficient than LA to inactivate S. Typhimurium. At the same time these combined technologies increased lipid (linear rate, R2adj = 0.88), protein oxidation (quadratic rate, R2adj = 0.86) and meat discoloration. Furthermore, the minimum point of the physicochemical changes was obtained using RSM, and the decontamination process was optimized. Hence, a reduction of 1.3 log cfu/g was achieved using 0.36 J/cm2 of UV and 7.7% of LA. These combined methods represent a promising industrial intervention strategy to dry-meat safety and quality.

Insights into chemical and sensorial aspects to understand and manage beer aging using chemometrics.

Beer chemical instability remains, at present, the main challenge in maintaining beer quality. Although not fully understood, after decades of research, significant progress has been made in identifying "aging compounds," their origin, and formation pathways. However, as the nature of aging relies on beer manufacturing aspects such as raw materials, process variables, and storage conditions, the chemical profile differs among beers. Current research points to the impact of nonoxidative reactions on beer quality. The effect of Maillard and Maillard intermediates on the final beer quality has become the focus of beer aging research, as prevention of oxidation can only sustain beer quality to some extent. On the other hand, few studies have focused on tracing a profile of whose compound is sensory relevant to specific types of beer. In this matter, the incorporation of "chemometrics," a class of multivariate statistic procedures, has helped brewing scientists achieve specific correlations between the sensory profile and chemical data. The use of chemometrics as exploratory data analysis, discrimination techniques, and multivariate calibration techniques has made the qualitatively and quantitatively translation of sensory perception of aging into manageable chemical and analytical parameters. However, despite their vast potential, these techniques are rarely employed in beer aging studies. This review discusses the chemical and sensorial bases of beer aging. It focuses on how chemometrics can be used to their full potential, with future perspectives and research to be incorporated in the field, enabling a deeper and more specific understanding of the beer aging picture.

Relationship between COVID-19 and weather: Case study in a tropical country.

This study aimed to evaluate the relationship between weather factors (temperature, humidity, solar radiation, wind speed, and rainfall) and COVID-19 infection in the State of Rio de Janeiro, Brazil. Solar radiation showed a strong (-0.609, p < 0.01) negative correlation with the incidence of novel coronavirus (SARS-CoV-2). Temperature (maximum and average) and wind speed showed negative correlation (p < 0.01). Therefore, in this studied tropical state, high solar radiation can be indicated as the main climatic factor that suppress the spread of COVID-19. High temperatures, and wind speed also are potential factors. Therefore, the findings of this study show the ability to improve the organizational system of strategies to combat the pandemic in the State of Rio de Janeiro, Brazil, and other tropical countries around the word.

Modeling Salmonella Typhimurium Inactivation in Dry-Fermented Sausages: Previous Habituation in the Food Matrix Undermines UV-C Decontamination Efficacy.

The effects of previous Salmonella Typhimurium habituation to an Italian-style salami concerning pathogen resistance against ultraviolet-C light (UV-C) treatment were modeled in order to establish treatment feasibility for the decontamination of dry-fermented sausage. S. Typhimurium following 24 h habituation in fermented sausage (habituated cells) or non-habituation (non-habituated cells) were exposed to increasing UV-C radiation treatment times. The Weibull model was the best fit for describing S. Typhimurium UV-C inactivation. Heterogeneity in UV-C treatment susceptibilities within the S. Typhimurium population was observed, revealing intrinsic persistence in a sub-population. UV-C radiation up to 1.50 J/cm2 was a feasible treatment for dry-fermented sausage decontamination, as the matrices retained instrumental color and lipid oxidation physiochemical characteristics. However, habituation in the sausage matrix led to a 14-fold increase in the UV-C dose required to achieve the first logarithm reduction (δ value) in S. Typhimurium population. The results indicate that, although UV-C radiation might be considered an efficient method for dry-fermented sausage decontamination, effective doses should be reconsidered in order to reach desirable food safety parameters while preserving matrix quality.

A Chemometric Approach to Establish Underlying Connections between Lipid and Protein Oxidation and Instrumental Color and Texture Characteristics in Brazilian Dry-cured Loin.

This study aimed to use chemometrics to evaluate the influence of lipid and protein oxidation on the color and texture characteristics of Brazilian dry-cured loin (Socol, BDL). Upon exploration using hierarchical cluster analysis (HCA), two clusters were formed, indicating that higher water activity (aw) was associated with higher lipid and protein oxidation. However, this fact was associated with softening and low color quality (a*, chroma, and cured color). In a more in-depth exploration, using principal component analysis (PCA) for each cluster separately, connections between protein and lipid oxidation were found in high aw, as demonstrated by their statistical association. In the same way, relationships between high hardness and carbonyl contents were obtained only in high aw. In addition, an overall relationship (p < 0.05) between nondestructive measurements, such as hardness, and destructive methods (malonaldehyde and carbonyl contents) demonstrate that nondestructive techniques can be promising for further studies in the method replacement field. In this study, reasonable explanations of the connections between oxidative damage and quality traits in Socol are provided.

Prior Exposure to Dry-Cured Meat Promotes Resistance to Simulated Gastric Fluid in Salmonella Typhimurium.

This study assessed if exposure of foodborne Salmonella enterica in Brazilian dry-cured loin (BDL) affects pathogen inactivation in simulated gastric fluid (SGF). The acid tolerance responses of three Salmonella enterica serovars, Typhimurium, Derby and Panama, were assessed by an acid challenge trial at pH 3.0 for 4 h following pre-adaptation to three conditions: neutral pH, acidic pH (4.5) or BDL matrix. The influence of Salmonella exposure temperature and time in the BDL on pathogen gastric fluid resistance was evaluated by the response surface methodology. The Salmonella serovars acquired acid tolerance when exposed to the BDL matrix and their response to acid stress was strain-dependent, with S. Typhimurium being the most tolerant strain. S. Typhimuirum exposed to temperatures >25 °C in the BDL matrix displayed increased resistance to SGF. By using the response surface methodology, it was determined that S. Typhimurium becomes less resistant against SGF if maintained in the BDL matrix at temperatures <7 °C, reinforcing the recommendation to store dry-cured meat under refrigeration in order to minimize consumer risks. The results presented herein point to a novel aspect of hurdle technology that should be taken into account to further understand the risks associated with hurdle-stable meat product, such as dry-cured meats, concerning foodborne pathogen contamination.

Modelling inactivation of Staphylococcus spp. on sliced Brazilian dry-cured loin with thermosonication and peracetic acid combined treatment.

Ultrasound (US) has a high capacity to increase food safety. Although high and/or moderate temperature in combination with US has been studied, the knowledge about cooling/low temperatures as well as its combined effect with chemical preservation methods is scarce. Therefore, the aim of this study was to describe the inactivation of Staphylococcus spp. (SA) present in the natural microbiota of sliced Brazilian dry-cured loin (Socol, BDL) using US (40 kHz and 5.40 W/g) at 1.6-17.9 kJ/g, temperature (T) between 6.4 and 73.6 °C and peracetic acid (PA) between 5.5 and 274.5 mg/L employing the Central Composite Rotatable Design. The model fully describes how the combination of US, T, and PA affects SA inactivation. In BDL, an increase in US acoustic energy density (kJ/g) allows the reduction of T necessary to inactivate SA because of the occurrence of synergistic effect. However, US applied at low T was inefficient. On the other hand, PA was more efficient at low T, since high T degraded this compound at different rates according to the holding T. Therefore, the data indicates a relation between the technologies used in the combined decontamination of sliced BDL improving dry-cured meat safety.

Short communication: Antimicrobial activity of pequi (Caryocar brasiliense) waste extract on goat Minas Frescal cheese presenting sodium reduction.

Sodium chloride reduction in foods is a significant focus of the dairy industry; however, it can interfere with dairy product quality. Thus, researchers have carried out studies on alternatives to maintain dairy product safety when presenting reduced NaCl content, such as natural antimicrobial addition. Caryocar brasiliense (pequi) is a fruit with high phenolic compound concentrations in the pulp and peel and known antioxidant and antimicrobial properties. This study aimed to define the optimum stage for pequi waste extract addition during cheese manufacturing in order to maintain and prolong the shelf life of reduced-sodium goat Minas Frescal cheese. Four different goat Minas Frescal cheese treatments were carried out: control cheese (without extract; CC), pequi extract addition to milk (CM), pequi extract addition to mass (CS), and cheese immersion in pequi extract (CIE). The treatments were subjected to microbiological (Staphylococcus spp., Escherichia coli, Enterobacteriaceae, coliforms and fecal coliforms, Lactococcus spp., and lactic acid bacteria counts), textural (hardness and consistency), and instrumental color (luminosity, yellow intensity, red intensity, chroma, hue angle, and total color change) analyses. No Enterobacteriaceae, Staphylococcus spp., E. coli, or coliforms and fecal coliforms were detected during storage for any of the assessed samples, including CC. Regarding texture, all samples presented a trend for decreasing rigidity during storage. In addition, lower luminosity values were also observed in cheeses produced with added pequi extract (CM, CS, and CIE) when compared with CC. All cheeses produced with added pequi were stable regarding all evaluated parameters; however, pequi extract addition to milk (CM) was shown to be more efficient, leading to higher textural parameters and better microbiological quality during storage. Thus, the CM treatment is the most recommended for pequi waste extract addition during Minas Frescal cheese manufacture.