Ohmic heating increases inactivation and morphological changes of Salmonella sp. and the formation of bioactive compounds in infant formula.

The effect of ohmic heating (OH) (50, 55, and 60 °C, 6 V/cm) on the inactivation kinetics (Weibull model) and morphological changes (scanning electron microscopy and flow cytometry) of Salmonella spp. in infant formula (IF) was evaluated. In addition, thermal load indicators (hydroxymethylfurfural and whey protein nitrogen index, HMF, and WPNI) and bioactive compounds (DPPH, total phenolics, ACE, α-amylase, and α-glucosidase inhibitory activities) were also studied. OH presented a more intense inactivation rate than conventional heating, resulting in a reduction of about 5 log CFU per mL at 60 °C in only 2.91 min, being also noted a greater cell membrane deformation, higher formation of bioactive compounds, and lower values for the thermal load parameters. Overall, OH contributed to retaining the nutritional value and improve food safety in IF processing.

Sheep milk kefir sweetened with different sugars: Sensory acceptance and consumer emotion profiling.

The objective of this study was to determine the sensory acceptance and emotional profile of sheep milk kefir sweetened with different sugars (demerara sugar, brown sugar, fructose, coconut sugar, and honey, 100 g/L). Consumers (n = 100) assessed sensory acceptance (appearance, aroma, taste, texture, and overall impression), and expressed their emotions (satisfied, active, loving, calm, comfortable, energetic, happy, healthy, refreshing, disgusted, worried, and upset). The emotions "satisfied," "active," "comfortable," "energetic," "healthy," and "refreshing" were found between moderate and very high levels, indicating that they are important emotions for the characterization and sensory acceptance of kefir samples. The use of different sugars had no influence on the intensity of the emotions "calm," "comfortable," "happy," or "disgusted," and resulted in a greater sense of satisfaction. The use of demerara sugar or fructose did not alter the acceptance of the products or the intensity of emotions. The use of brown sugar decreased acceptance (taste, texture, and overall impression) and the intensity of the emotions "active," "loving," "energetic," "healthy," and "refreshing." The use of coconut sugar decreased acceptance (appearance, aroma, and taste) and the intensity of the emotions "refreshing" and "upset." The use of honey improved acceptance in appearance and aroma but reduced the intensity of the emotions "active," "loving," "energetic," and "healthy." Based on sensory data, it is recommended to use demerara sugar or fructose as a substitute for sucrose. In conclusion, the study of emotions can be used as an additional tool for obtaining data related to the sensory acceptance of products.

Effect of probiotic Minas Frescal cheese on the volatile compound and metabolic profiles assessed by nuclear magnetic resonance spectroscopy and chemometric tools.

This study aimed to evaluate the effect of Lacticaseibacillus casei 01 as a probiotic culture on the production of volatile organic compounds and metabolic profile of Minas Frescal cheese. Lactose (α-lactose and ß-lactose), fatty acids (unsaturated and saturated), citric acid, tryptophan, and benzoic acid were the main compounds. Compared with the control cheese, probiotic cheese was characterized by the highest concentration of tryptophan and presented a higher number of volatile acids. The control cheese was characterized by the highest concentration of benzoic acid and fatty acids, resulting in a higher number of volatile alcohols and esters. No differences were observed for α-lactose, ß-lactose, and citric acid contents. A clear separation of probiotic and control Minas Frescal cheese was obtained using 1H nuclear magnetic resonance spectra, demonstrating that the addition of probiotic culture altered the metabolic profile of Minas Frescal cheese. Overall, the findings suggested that the addition of probiotic culture promoted the proteolysis in the fresh cheeses, decreased the lipolysis, and altered the volatile compounds. Furthermore, nuclear magnetic resonance spectroscopy coupled to chemometrics tools could be used to differentiate probiotic and conventional cheeses.

Effect of Lactobacillus rhamnosus on growth of Listeria monocytogenes and Staphylococcus aureus in a probiotic Minas Frescal cheese.

This study aimed to evaluate the effect of Lactobacillus rhamnosus GG on growth of Staphylococcus aureus and Listeria monocytogenes, inoculated alone or in combination on surface of Minas Frescal cheeses, during storage for 21 days at 7 °C. Survival percentages of each individual bacterial species after exposure to in vitro simulated gastrointestinal conditions (SGC) were also determined. The addition of L. rhamnosus did not affect (P > 0.05) pH, moisture, fat, protein and texture profile of Minas Frescal cheeses. L. rhamnosus was able to survive in suitable counts (>6 Log CFU/g) in cheeses from the 7th day of storage, with high survival (>74.6-86.4%) after SGC. An inhibitory effect of L. rhamnosus on L. monocytogenes was observed in cheeses (decrease of 1.1-1.6 Log CFU/g) and after SGC (20% reduction in the survival). No inhibitory effect of L. rhamnosus was observed on S. aureus counts (P > 0.05), and this microorganism did not survive the exposure to SGC. In conclusion, the addition of L. rhamnosus in Minas Frescal cheese has a potential for L. monocytogenes inhibition. Further studies are necessary to elucidate the mechanisms involved in the inhibition process and determine the survival ability of the bacterial species evaluated in in vivo experiments.

Food defense: Perceptions and attitudes of Brazilian dairy companies.

This study aimed to evaluate the perception of Brazilian dairy processors (n = 31) concerning food defense. The results showed that respondents consider the implementation of control procedures related to facilities, products, materials, and individuals as important measures in food defense. The higher agreement rates (strongly agreed + slightly agreed) of the companies in relation to the perception of food defense were 84% for external security, followed by personnel security (82%), generalities (81%), and internal security (74%). Thus, protecting facilities and controlling the traffic flow were considered to be the most important actions under the participants' perspectives. Employee satisfaction and identification of end products and raw materials are also considered relevant in the food defense program. Although food defense is not a formal requirement in Brazilian law, the results show that there is adequate awareness of this topic by the Brazilian dairy companies.

Quantitative microbiological risk assessment for the occurrence of listeriosis in Brazil due to the consumption of milk processed by pasteurization or thermosonication.

This study aimed to estimate the risk of listeriosis from the consumption of pasteurized milk in Brazil, comparing conventional treatment with the technology of thermosonication. The Quantitative Microbiological Risk Assessment (QMRA) model was developed, covering the entire milk production chain, from milking to the moment of consumption. In general, higher risks were observed in association with higher initial concentrations of the pathogen and the vulnerable population. The highest risk predicted (3.67 × 10-5) was related to the scenario considering the initial concentration range of L. monocytogenes between 4 and 6 log CFU/mL, with conventional treatment and considering the vulnerable population, resulting in one case of listeriosis every 27,248 servings. When considering thermosonication treatment, lower risks have been predicted. The scenario analysis indicated that the steps related to storage conditions in retail and at the consumer's home (post-processing steps) are the most influential in the associated risk, in all scenarios. The predictive parameters of inactivation related to the applied treatment also have a considerable influence on the risk. The results point to the influence of the stages of the dairy production chain and the thermosonication treatment applied in the food safety of milk, subsidizing information for industrial application and for regulatory agencies.

Influence of different levels of ethnocentrism of the Brazilian consumer on the choice of dulce de leche from different countries of origin.

Dulce de leche, a concentrated dairy product with high added value, is an essential product of Brazilian culture. However, with a competitive market among economic blocks, it is important to know if the country of origin influences the perception of consumers and the intention to purchase a product, aiming to boost production in the domestic market. This study aimed to assess the impact of different levels of ethnocentrism on the consumer perception and buying behavior toward dulce de leche (DL) from other countries (Argentina, Uruguay, and Brazil). Through an online survey, participants' demographic data (n = 224) was collected. Then they were encouraged to identify the purchase motivation using the Hard Laddering (HL) methodology and to assess the consumer's level of ethnocentrism (CE) with CESTSCALE. Three distinct groups were identified: high, moderate, and low ethnocentric. Consumers with high CE declared themselves conservative, with a more significant number of self-employed workers, and prefer and always buy national products. This group had a robust dominant chain only for the national product, highlighting the flavor and quality, and values ​​of nationalism and solidarity with local producers. On the other hand, consumers with low CE were self-declared liberal and had a higher level of education. They demonstrated significantly more favorable attitudes and intentions towards purchasing imported products due to improved quality, although patriotic behavior was also evident. We conclude that with CETSCALE, it was possible to identify that the sample of the Brazilian population studied has different levels of CE, which strongly impact the purchase attitude of products, especially the imported ones. However, it was only through the HL technique that it was noticed that, in addition to its intrinsic characteristics, patriotism is an important factor for the product and can be used as a sales motivator. This study demonstrated the importance of promoting the development of DL in the domestic market and encourage aspects of the origin, as they are fundamental in the choice of this product by the consumer, which helps local industries.

Ohmic heating processing of milk for probiotic fermented milk production: Survival kinetics of Listeria monocytogenes as contaminant post-fermentation, bioactive compounds retention and sensory acceptance.

The survival kinetics of Listeria monocytogenes (9 log CFU/mL) as a post-fermentation contaminant in probiotic fermented milk (Lactobacillus acidophilus La-5, 8-9 log CFU/mL) processed with milk subjected to ohmic heating (0, 4, 6, and 8 V/cm; CONV, OH4, OH6, OH8, 90-95 °C/5 min) was investigated using Weibull predictive model. Additionally, the presence of bioactive compounds (antioxidant activity, inhibition of the enzymes α-glucosidase, α-amylase, and angiotensin-converting) and sensory analysis (consumer test) of probiotic fermented milks were evaluated. Overall, OH provided a decrease in the viability of Listeria monocytogenes, suitable Lactobacillus acidophilus counts, and satisfactory results in the gastrointestinal tract survival. The Weibull model presented an excellent fit to the data of all conditions. Furthermore, lower δ values (217-298 against 665 h, CONV), and increased R2 values (0.99 against 0.98, CONV) were obtained for the OH-treated samples, emphasizing the best performance of OH data. In addition, OH improved the generation of bioactive compounds as well as the sensory acceptance. Indeed, considering functional and safety purposes, OH presented as an interesting technology to be used in milk for manufacturing probiotic fermented milk.

Impact of cold plasma on the techno-functional and sensory properties of whey dairy beverage added with xylooligosaccharide.

This study aimed to evaluate the impact of cold plasma (0, 5, 10, or 15 min) on the techno-functional and sensory properties of whey dairy beverages added with xylooligosaccharide (XOS, 1.5% p/v). Untreated and pasteurized whey beverages were also evaluated. The products were evaluated for physicochemical characteristics, bioactive compounds, XOS stability, rheological properties, and sensory characteristics. Cold plasma and pasteurized products presented lower color intensity (L*=87.4-87.9, a*=-0.24- -0.60, b*=2.41-5.19), reduced consistency (K = 4.31-42.21 mPa.sn and N = 0.57-0.95), and similar apparent viscosity, XOS chemical stability, and sensory characteristics compared with the untreated product. However, the cold plasma-treated beverages presented lower heat load indicators (hydroxymethylfurfural [HMF] values of 1.91-2.10 µmol/L and whey protein nitrogen index [WPNI] of 6.09-6.66 µmol/L) and a higher concentration of bioactive compounds (antioxidant activity [5.31-9.30%], and inhibition of ACE [14.17-22.53%], α-amylase [18.52-25.67%] and α-glucosidase [22.50-27.50%] activities) than the pasteurized product, being the effects more pronounced for the higher exposure times. Overall, cold plasma has important advantages for the processing of whey beverages added with XOS.

Paraprobiotic obtained by ohmic heating added in whey-grape juice drink is effective to control postprandial glycemia in healthy adults.

The effect of paraprobiotic Lacticaseibacillus casei 01 inactivated by ohmic heating (8 V/cm, 95 °C/7 min, 60 Hz) whey-grape juice drink at the postprandial glycemia was evaluated. In vitro hypoglycemic activity was assessed by the α-glucosidase and α-amylase inhibition, while in vivo activity was determined using 15 healthy subjects, which consumed bread + probiotic whey drink, bread + paraprobiotic whey drink, and bread alone as a control. The probiotic and paraprobiotic grape-flavored whey drinks showed similar α-glucosidase and α-amylase inhibition (51.2 vs 51.8% and 43.2 vs 44.2%, respectively). The consumption of both paraprobiotic and probiotic whey drinks increased the incremental glucose rate when compared to the control due to the presence of sugar in its composition, without changes in the other parameters evaluated (maximum glucose value, glucose incremental percentage, and peak blood glucose time), showing a reduced glycemic response. In addition, the consumption of the paraprobiotic drink maintained the maximum glucose increase similar to the control, while an increase in this parameter was observed after the consumption of the probiotic drink. Therefore, the paraprobiotic grape-flavored whey drink may be an effective alternative to replace the probiotic product in reducing the postprandial glycemia in healthy individuals.

Ohmic heating as a method of obtaining paraprobiotics: Impacts on cell structure and viability by flow cytometry.

This study aimed to evaluate the effects of ohmic heating (OH) on probiotic inactivation, cell viability and morphology of the probiotic strains Lactobacillus acidophilus LA 05 (LA), Lacticaseibacillus casei 01 (LC), and Bifidobacterium animalis Bb 12 (BA) to develop paraprobiotics. OH at different electric field magnitudes (4, 8, and 12 V/cm at 60 Hz) and conventional heat treatment (CONV) were performed to determine the most adequate condition for the obtainment of paraprobiotics. Analysis of culturability, flow cytometry (FC), and Scanning electron microscope (SEM) was carried out. The complete inactivation by CONV was achieved only in the following conditions: LA - 95 °C/5 min, LC and BA - 95 °C/7 min. The same temperature profile was used in OH treatments to study the OH electrical effects. The OH treatment (8 V/cm) caused lower damage to the cell membrane integrity compared to the CONV treatment (p < 0.05). The OH showed to be adequate technology for the efficient production of paraprobiotics.

Can sucrose-substitutes increase the antagonistic activity against foodborne pathogens, and improve the technological and functional properties of sheep milk kefir?

The effect of different types of sugar (sucrose, demerara, brown, fructose, coconut sugar, and honey) on sheep milk kefir was evaluated. Microbial counts (Lactobacillus, Lactococcus, Leuconostoc, yeast), antagonistic activity against foodborne pathogens, microstructure (scanning electron microscopy), and antiproliferative activity of cancer cells were evaluated. Furthermore, the antioxidant activity (DPPH), inhibitory activity of angiotensin-converting enzyme (ACE), α-amylase, and α-glucosidase, lactose content, lactic and acetic acids and ethanol, fatty acid profile and volatile organic compounds were determined. The addition of sugars increased the Lactobacillus population (up to 2.24 log CFU/mL), metabolites concentration, antagonistic activity against pathogens, antioxidant activity (11.1 to 24.1%), ACE inhibitory activity (27.5 to 37.6%), α-amylase inhibition (18 to 37.4%), and anti-proliferative activity. Furthermore, it improved the fatty acid profile and volatile compounds. The results suggest that the replacement of sucrose with different types of sugar constitute an interesting option to be used in sheep milk kefir formulations.

Antiproliferative and apoptotic effects of probiotic whey dairy beverages in human prostate cell lines.

The present study aimed to evaluate the antiproliferative and apoptotic effects of probiotic whey dairy beverages in human prostate cancer cell lines (PC-3 and DU-145). Five different whey beverages were manufactured: conventional whey beverage (without addition of probiotic strain, CTL); and whey beverages containing Lactobacillus acidophilus La-05, Lactobacillus acidophilus La-03, Lactobacillus casei-01, and Bifidobacterium animalis Bb-12. Cell viability was determined by MTT assay and cell cycle arrest, and apoptosis by flow cytometry. All the samples presented cytotoxic activities against both cell lines. A decrease in the percentage of PC-3 cells in G0/G1 and S, followed by an increase in G2/M phase were observed with L. casei-01, Bb-12 and La-05 beverages (50.0 and 100.0 µg/mL). The extracts of the whey beverages caused extensive apoptosis induction in both cells' lines, regardless of the probiotic strain. However, the whey beverage added with L. casei-01 might be a better candidate against prostate cancer cells.

Dulce de leche submitted to ohmic heating treatment: Consumer sensory profile using preferred attribute elicitation (PAE) and temporal check-all-that-apply (TCATA).

This study aimed to evaluate the effects of the application of ohmic heating (OH) to milk (0, 2, 4, 6, 8, or 10 V cm-1, 72-75 °C/15 s) on the sensory profiling of dulce de leche (DL) evaluated using preferred attribute elicitation (PAE) and temporal Check-all-that-apply (TCATA) methodologies. In addition a consumer test was also performed. OH-DL samples presented increased scores for all the sensory attributes evaluated. Low or intermediate strength electric fields contributed to increase bitter taste and decrease DL aroma and sweet taste of the products, without impact on the overall liking. When high strength electric fields were applied, higher brightness, fluidity and DL flavor scores were observed, as well as, lower intensities in consistency and sandiness scores, resulting in increased acceptance by consumers. From TCATA data, it could be observed that the perception of all sensory attributes increased as well as increased the strength of the electric fields. Overall, the adoption of electric fields with higher strength in ohmic heating during DL processing is advised, since they improved the intensity and perception of desirable intrinsic DL sensory attributes as well as improved DL overall liking.