Total Mesophiles Research Articles

The Effect of High Intensity Ultrasound on the Quality and Shelf Life of Tilapia (Oreochromis niloticus) Muscle

It has been documented that the shelf life of fishery products is extremely reduced due to microbial development and its endogenous biochemistry. For this reason, food technologists around the world are researching how to reduce the main processes that lead to spoilage. Recently, high-intensity ultrasound (HIU) has had different applications in the food industry because the cavitation effect can inhibit or reduce microbial development as well as cause conformational changes in muscle enzymes. Therefore, in this study, HIU was applied for 30, 60, and 90 min to the tilapia (Oreochromis niloticus) fillet, and subsequently, it was stored on ice for 20 days. During this period, samples were taken every 5 days (day 0, 5, 10, 15, and 20), and moisture content, pH, total volatile base (TVB-N), non-protein nitrogen (NPN), texture, electrophoresis, color, and microbiological analyses (mesophiles and psychrophiles) were determined. No significant changes (p ≥ 0.05) were observed in the moisture content, pH, and the L* parameter, while a significant decrease (p < 0.05) in TVB-N (from 29.67 to 15.09), NPN (from 0.39 to 0.27%), and texture (from 4.88 to 2.69 N) were found. On the other hand, an increase (p < 0.05) in a* (from 2.02 to 4.27) and b* (from 10.66 to 12.45) parameters, as well as total mesophile count (from 2.48 to 6.52 log CFU/g) were detected due to the application of ultrasound. The results suggest that the application of this treatment represents a viable alternative to increase the shelf life and quality of tilapia fillets stored on ice.

Metagenomic analysis of the bacterial microbiome, resistome and virulome distinguishes Portuguese Serra da Estrela PDO cheeses from similar non-PDO cheeses: An exploratory approach

This study aimed to evaluate the microbiome, resistome and virulome of two types of Portuguese cheese using high throughput sequencing (HTS). Culture-dependent chromogenic methods were also used for certain groups/microorganisms. Eight samples of raw ewe’s milk cheese were obtained from four producers: two producers with cheeses with a PDO (Protected Designation of Origin) label and the other two producers with cheeses without a PDO label. Agar-based culture methods were used to quantify total mesophiles, Enterobacteriaceae, Escherichia coli, Staphylococcus, Enterococcus and lactic acid bacteria. The presence of Listeria monocytogenes and Salmonella was also investigated. The selected isolates were identified by 16S rRNA gene sequencing and evaluated to determine antibiotic resistance and the presence of virulence genes. The eight cheese samples analyzed broadly complied with EC regulations in terms of the microbiological safety criteria. The HTS results demonstrated that Leuconostoc mesenteroides, Lactococcus lactis, Lactobacillus plantarum, Lacticaseibacillus rhamnosus, Enterococcus durans and Lactobacillus coryniformis were the most prevalent bacterial species in cheeses. The composition of the bacterial community varied, not only between PDO and non-PDO cheeses, but also between producers, particularly between the two non-PDO cheeses. Alpha-diversity analyses showed that PDO cheeses had greater bacterial diversity than non-PDO cheeses, demonstrating that the diversity of spontaneously fermented foods is significantly higher in cheeses produced without the addition of food preservatives and dairy ferments. Despite complying with microbiological regulations, both PDO and non-PDO cheeses harbored potential virulence genes as well as antibiotic resistance genes. However, PDO cheeses exhibited fewer of these virulence and antibiotic resistance genes compared to non-PDO cheeses. Therefore, the combination of conventional microbiological methods and the metagenomic approach could contribute to improving the attribution of the PDO label to this type of cheese.

Impact of intense sanitization procedures on bacterial communities recovered from floor drains in pork processing plants.

Pork processing plants in the United States (US) cease operations for 24-48 h every six or twelve months to perform intense sanitization (IS) using fogging, foaming, and further antimicrobial treatments to disrupt natural biofilms that may harbor pathogens and spoilage organisms. The impact such treatments have on short-term changes in environmental microorganisms is not well understood, nor is the rate at which bacterial communities return. Swab samples were collected from floor drains to provide representative environmental microorganisms at two US pork processing plants before, during, and after an IS procedure. Samples were collected from four coolers where finished carcasses were chilled and from four locations near cutting tables. Each sample was characterized by total mesophile count (TMC), total psychrophile count (TPC), and other indicator bacteria; their biofilm-forming ability, tolerance of the formed biofilm to a quaternary ammonium compound (300 ppm, QAC), and ability to protect co-inoculated Salmonella enterica. In addition, bacterial community composition was determined using shotgun metagenomic sequencing. IS procedures disrupted bacteria present but to different extents depending on the plant and the area of the plant. IS reduced TPC and TMC, by up to 1.5 Log10 CFU only to return to pre-IS levels within 2-3 days. The impact of IS on microorganisms in coolers was varied, with reductions of 2-4 Log10, and required 2 to 4 weeks to return to pre-IS levels. The results near fabrication lines were mixed, with little to no significant changes at one plant, while at the other, two processing lines showed 4 to 6 Log10 reductions. Resistance to QAC and the protection of Salmonella by the biofilms varied between plants and between areas of the plants as well. Community profiling of bacteria at the genus level showed that IS reduced species diversity and the disruption led to new community compositions that in some cases did not return to the pre-IS state even after 15 to 16 weeks. The results found here reveal the impact of using IS to disrupt the presence of pathogen or spoilage microorganisms in US pork processing facilities may not have the intended effect.

Oleogels based on germinated and non-germinated wheat starches and orange essential oil: Application as a hydrogenated vegetable fat replacement in bread

This study aimed to produce oleogels based on non-germinated and germinated wheat starches with orange essential oil, apply them to replace hydrogenated vegetable fat in bread, and assess the antifungal action. The oleogels were prepared using sunflower oil, wheat starches, beeswax, water, and orange essential oil (OEO). They were evaluated to determine the volatile compounds, oil binding capacity, texture profile, storage stability for 20 days, thermogravimetric analysis, and functional groups. The breads were evaluated by their moisture content, specific volume, texture profile, volatile compounds, and microbiological contamination during 15 days of storage. The oleogels showed high storage stability, were fully intact after 20 days of storage, and had a high oil binding capacity (∼100 %). The oleogels with OEO presented increased adhesiveness and reduced hardness compared to the ones without essential oil. The oleogels with OEO based on germinated wheat starch released a high amount of volatile compounds. Substituting saturated vegetable fat with oleogels in bread formulation resulted in decreased hardness and maintained specific volume. Furthermore, incorporating OEO oleogels in the bread led to reduced growth of total mesophiles and fungi.

Comparing Different Packaging Conditions on Quality Stability of High-Pressure Treated Serra da Estrela Cheeses during Cold Storage.

Serra da Estrela cheese with a Protected Designation of Origin (PDO) is a traditional cheese that is wrapped in paper without vacuum. High-pressure processing (HPP), which requires vacuum packaging of the cheese, has been used for its cold pasteurization to overcome safety issues. In this study, two packaging systems were studied: non-vacuum greaseproof paper wrapping package and vacuum packaging in plastic film. Lactococci, lactobacilli, enterococci, and total mesophiles reached ca. 8 log cfu g-1 and 4-6 log cfu g-1 in control (unpasteurized) and HPP-treated cheeses, respectively, with no significant differences between packaging systems. Spoilage microorganisms' viable cell numbers were reduced to <3 log cfu g-1 (quantification limit) in HPP-treated cheeses, independently of the packaging system. Yeasts and molds reached >5 log cfu g-1 in non-vacuum paper-wrapped cheeses. A vacuum-packaging system enabled better control of cheese proteolysis, which was revealed to be closer to that of the original control cheese values at the end of the 10-month storage period. In addition, cheese stored under vacuum film packaging became harder than non-vacuum paper-wrapped cheeses at each time point. Overall, conventional non-vacuum paper wrapping is adequate for short storage periods (<3 months), but for long periods vacuum packaging in plastic film is preferable.

Microbiological quality and antimicrobial resistance of Salmonella spp. and Escherichia coli isolated from grilled meat

In Chad, grilled meat has been well appreciated and consumed regularly. However, it could be the cause of many diseases if handled under unhygienic conditions. The objective of this study was to evaluate the microbiological quality and antimicrobial resistance profile of strains of Salmonella spp. and Escherichia coli isolated from grilled meat in the city of N'Djamena. Thirty producers were surveyed at least once from 02 August 2018 to 31 January 2019 and one grilled meat sample was collected from each of them. Total Mesophile Aerobic Flora (TMAF), Thermotolerant Coliform (TTC), Escherichia coli and Salmonella spp. counts, as well as susceptibility testing, were conducted at the Food and Nutrition Sciences Research Laboratory in N'Djamena according to standard methods. The level of the contamination of grilled meats was 83.33% for TMAF and 56.67% for TTC. The prevalence of Escherichia coli was 36.36%. Resistance was observed with some antibiotics especially those to the beta-lactam family. This study revealed that the grilled meat can expose the consumers to a sanitary risk. It should be stressed the strict application of good hygiene practices.

Wort disinfection treatment with electron beam for bioethanol production

Microbial contamination of the wort during the fermentation process causes significant losses in ethanol production worldwide and creates a dependence of the industry on chemicals and antibiotics to control contamination. Therefore, this study used electron beam (e-beam) to disinfect wort from sugarcane (Saccharum officinarum L.) molasses and investigate the bioethanol fermentation. Four treatments (T0 – T3) were carried out using ionizing doses of radiation through the electron accelerator: 0 (control), 10, 20, and 40 kGy. Total mesophiles, total bacteria, sucrose, glucose, fructose, phenolics, flavonoids, hydroxymethylfurfural (5-HMF), and Furfural were measured. An alcoholic fermentation assay was performed after the irradiation process. The irradiated treatments showed no inversion of sugars and formation of the inhibitory by-products flavonoids, furfural and 5-HMF, except for the phenolic compounds. The lower dose tested (10 kGy) reduced more than 99.9 % of the total mesophiles and more than 99.99 % of the total bacteria in the substrate. In the fermentation, the irradiated worts presented similar (p > 0.05) yields (92, 93, and 94 %) and ethanol productivity levels (0.89, 0.88, and 0.87 g L–1 h–1, for T1, T2, and T3 respectively). However, all treatments presented higher yields and productivity (p < 0.05) when compared to the control (88 % and 0.85 g L–1 h–1), highlighting the possible use of e-beam in wort fermentation at a lower dose (10 kGy). This allows reduction in losses caused by microbial contamination, besides increasing fermentation yield and productivity with lower energy consumption.

Chocolate coverage based on two Ecuadorian varieties CCN51 and Super Tree in the province of Pastaza, Ecuador

Objective: Its objective is to produce a bitter-type chocolate coating from the combination of cocoa of the CCN51 and Super Tree variety. Methodology: the product was elaborated through an experimental, quantitative, and qualitative method. Results: 18 experimental units were generated in the design, where 2 formulations with 2 replications were obtained, which allowed us to determine the best treatment through sensory analysis with a structured hedonic scale of acceptability (assessment from 1 to 5). The sensory evaluation was carried out with 30 untrained panelists, where they determined that T1 with 70% cocoa liquor is the most accepted, while for the trained judges there was no significant difference. The samples were subjected to bromatological analysis, obtaining as a result a moisture content of 1.59%, fat 37.86%, protein 9.26%, ash 2.04%, dry extract of defatted cocoa 99.38%, dry extract of total cocoa 98.41%, microbiological less than 100 cfu. ml-1 in total mesophiles, yeasts, and total coliforms. Limitations: have pilot equipment for processing. Conclusions: The parameters of the best treatment T1 are framed in the NTE INEN 621: 2010 in force in Ecuador for the manufacture of chocolates.

Comparative Effects of Probiotic, Prebiotic, L-Arginine, and Fenugreek on Some Quality Criteria of Fermented Red Meat Pâtè

The different combinations of bioactive compounds, probiotics (Streptococcus thermophilus ATCC 19258 and Lactobacillus bulgaricus BAA-2844), prebiotic (fructooligosaccharides, FOS), fenugreek, and L-arginine, were added to the pâtė meat. Some pâtė meats were contaminated with Salmonella Typhimurium ATCC 14028 and Listeria monocytogenes ATCC 7644. Fermentation was applied only to batches containing ‘probiotic’ or ‘probiotic and prebiotic’ at two different temperatures, 22 and 37°C. Although fermentation at 37°C in combination with the additions of ‘probiotics, prebiotic and arginine’ and ‘probiotics, prebiotic and fenugreek’ resulted in 2.51 and 2.36 log (cfu/g) reductions on total mesophile aerobic bacterial (TMAB) counts, respectively, these treatments lowered the pH values of pâtė below 4.20 on the 22nd day of storage and caused an uncontrolled fermentation with a sourish taste. On the other hand, the combined additions of ‘probiotics, prebiotic, fenugreek and arginine’ or ‘probiotics, prebiotic and arginine’ or ‘probiotic, prebiotic and fenugreek’ in combination with fermentation at 22°C, caused reductions on TMAB counts between 1.01-1.09 log (cfu/g) with a constant bacteriostatic effect, and extended shelf life 10 days while improving the sensory quality. The addition of fenugreek inhibited Listeria monocytogenes more whereas the antimicrobial effect of L-arginine was more significant on Salmonella Typhimurium. The antimicrobial effect of adding the bioactive compounds in combination with fermentation at 22°C could eliminate the pathogens in the contaminated pâtė meat batches, causing 5.91 and 6.11 log (cfu/g) reductions on the counts of Salmonella Typhimurium and Listeria monocytogenes, respectively.

Cilantro and Coriander Yield as Affected by Cultivars and Row Spacings in Fall and Spring Production in Virginia

This student-led project studied the production of cilantro (greens stage) and coriander (seed stage) of Coriandrum sativum L. with the objective of developing this crop as an alternate specialty crop in Virginia. Results indicated that both fall-planted for spring harvest and spring-planted for summer harvest are possible in Virginia. Rows spaced 37.5 cm apart resulted in the superior yield of both cilantro and coriander over rows 75 cm apart. Mean cilantro fresh yields from fall-planted experiments (three cultivars during 2015 and five cultivars during 2016) varied from 3301 to 5775 kg⋅ha−1, whereas those from spring-planted experiments varied from 4971 to 11811 kg⋅ha−1. Corresponding values for dry cilantro yields varied from 274 to 1129 kg⋅ha−1 and 862 to 2280 kg⋅ha−1, respectively. Mean coriander seed yields from three fall-planted cultivars varied from 818 to 1554 kg⋅ha−1, and those from three spring-planted cultivars varied from 869 to 1277 kg⋅ha−1. The total phenolic content in cilantro was significantly greater than that in coriander seed (4.95 and 1.15 g of gallic acid equivalent per 100 g of material, respectively). The total mesophiles, yeast and mold, and coliforms from three grocery store-bought cilantro were considerably higher than those of greenhouse-grown cilantro. Even though both spring and fall plantings are possible for supplying cilantro in Virginia, fall planting for spring harvest might be more profitable for producers because of the earlier availability of locally grown cilantro.

Chocolate couvertures development from combination of CCN51 and Super Tree cocoa varieties, in the Pastaza Province

Dark chocolate coatings contain a high percentage of cocoa, which is pleasing to the consumer’s taste. The aim of the research was to develop a bitter-type chocolate coating from the combination of CCN51 and super tree cocoa. In this study, an experimental method, with 18 treatments was applied. In the sensory analysis a hedonic scale test with 30 untrained judges and 15 trained ones was carried out, applying a completely random unifactorial design. The judges determined that T1 treatment with a content of 70% cocoa liquor, had a mean value of 3.8, while the value for the untrained judges was not significance. A bromatological analysis of the best treatment was made based on the NTE INEN 621:2010, resulting in moisture content of 37.86%, fat 9.26%, protein 2.04% and ash 99.38%, defatted cocoa dry extract 98.41%, dry extract of total cocoa and microbiological results less than 100 ufc.ml-1 in total mesophiles, yeasts and total coliforms, parameters that are within the permissible limit.

Ohmic heating treatment in high-protein vanilla flavored milk: Quality, processing factors, and biological activity

The processing of high-protein vanilla-flavored milk was performed under different electric field strengths of ohmic heating (5.22 V/cm, OH6; 6.96 V/cm, OH8; 8.70 V/cm, OH10; 10.43 V/cm, OH12) to evaluate the energy consumption, processing parameters, and microbiological, rheological, and biological aspects, compared with the sample submitted to conventional pasteurization (PAST, 72 °C/15 s). All samples showed higher than 12 g/100 mL of protein, consisting of high-protein content products. In addition, Ohmic Heating (OH) generated lower energy expenditure and more significant microbial inactivation of lactic acid bacteria, molds and yeasts, total mesophiles, and psychotropics. Furthermore, OH at lower electric field strengths, mainly OH8, improved anti-diabetic, anti-oxidant, and anti-hypertensive activities and rheological properties, and resulted in lower hydroxymethylfurfural contents, and higher whey protein nitrogen index. The results suggest that OH is a technology that can be used in flavored milk with high-protein content, being recommended an electric field strength of 6.96 V/cm. However, more studies are necessary to evaluate the effect of OH on high-protein dairy products, mainly by studying other OH processing parameters.

Hospital effluent care with ozone for inactivation of potentially pathogenic bacteria

Hospital effluents are characterized as possible vehicles for the dissemination of numerous pathogenic microorganisms and other contaminants and, when left untreated, represent a potential risk to man and the environment. The objective of this research was to evaluate the presence of arable pathogenic microorganisms present and to verify the efficacy of ozone in the disinfection of effluents from a public hospital in the city of Uberlandia-MG. Hospital effluent collections were performed at two points, with a distance of 200 m: the first point, from the Emergency Room, wards, intensive care unit, surgical center and laboratory and the second point, hemodialysis, kitchen, laundry and clothing. Sampling was performed for three months. The samples were evaluated for the presence of total mesophiles, total and thermotolerant coliforms, Escherichia coli and Salmonella spp. The effluent was treated with ozone for different periods of time. The presence of mesophiles, coliforms, Escherichia coli and Salmonella spp. was verified in both effluents and in all months of evaluation. Ozone was effective in decontamination of hospital effluent, requiring 20 minutes to eliminate bacterial load.

Basil, marjoram, nutmeg and oregano essential oils as natural preservatives of Quark-type cheese

This study aims to evaluate the in vitro antimicrobial activity of basil, marjoram, nutmeg, and oregano essential oils to use the essential oil with better results for Quark-type cheese preservation. To verify the shelf life of Quark-type cheese without essential oil (CTL) and Quark-type cheese added with 0.05% essential oil (OE), microbiological and physicochemical analyses were performed for 35 days (4 °C). The acceptability of the product was also evaluated. The oregano essential oil showed strong antimicrobial activity in the disk-diffusion test (34.0 to 51.0 mm), and lower values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against all species of bacteria tested. A lower mold and yeast count (p < 0.05) was observed during storage in OE denoting a positive effect in delaying its deterioration. On the other hand, there was no difference (p > 0.05) between the CTL and OE count of total mesophiles and Enterobacteriaceae. For the physicochemical parameters evaluated, there were no significant differences between the CTL and OE, thus denoting that the typical characteristics of this cheese were maintained. The Quark-type cheese added with oregano essential oil also showed good acceptability (> 7), which is a way to preserve the product with a natural additive.

Influence of bionanoparticles to treat a slaughterhouse wastewater

ABSTRACT Treatment of effluents from animal slaughterhouse industries is indispensable, standing out coagulation/flocculation/sedimentation processes. Bionanoparticles (BioNPs) (nanoparticles (NPs) functionalized with Moringa extracts (MO)) were studied as an alternative natural coagulant that would contribute to the microbial load reduction, without increasing the treated effluent toxicity. MO extracts were prepared with different salts, and then, in a kinetics study, different NPs mass and coagulant dosages were evaluated. In the best-defined conditions, microbial load, toxicity tests for the bioindicator Lactuca sativa, and NPs reuse evaluation were performed. Removals of 96.14% turbidity and 43.63% UV254nm were achieved when using 500 mg L−1 of BioNPs containing 60 mg of NPs for every 20 mL of MO extract prepared with 0.1 M CaCl2. The BioNPs with an external magnetic field also decreased the sedimentation time from 140 to 10 min compared to MO, and the process efficiency did not expressively decrease after reusing the recovered NPs. Through toxicity tests, BioNPs were not considered to leave residuals toxic to the Lactuca sativa in the treated effluent. Besides, the microbial load reduction was 97.33% for heterotrophic microorganisms and total mesophiles and 99.25% for moulds/yeasts. Therefore, a satisfactory primary treatment was achieved, contributing to the sustainability of industries.

Physical, chemical and microbiological characterization of cupuassu seed during fermentation

The cupuassu’s seeds are similar to cocoa, being possible to apply fermentative techniques used to obtain nibs and cupulate. The aim of this work to study the physicochemical transformations during the cupuassu´s seeds fermentation. For this purpose, frozen seeds from a pulp processing industry were fermented in three batches of 20 kg for seven days at room temperature. During the fermentation process, seed mass temperature, dimensions, density and composition of the kernels, color indexes (L*, C* and H*), microbiological analyzis (mesophiles, molds and yeasts), cut-proof, physicochemical analyzis (pH, acidity and glucose reducing sugars and non sucrose reduction) and centesimal composition (ashes, lipids, proteins and carbohydrates) were analyzed from triplicates. The results were expressed as dry basis. During the fermentations, the great temperatures were reached. The maximus were 43,44 and 47 ºC in three fermentations. It was observed during the fermentation process: seed darkening (L*) and color intensity reduction (Chroma), pH increase, sugar reduction and acidity reduction. The ash, lipid and protein contents were not significantly influenced by the fermentation time. According to the cut test, the kernels of 3rd fermentation, whose maximum temperature was higher, were classified as type 2 and the others as type 3. The values of apparent density, dimensions, mass and composition of seeds demonstrated that during the fermentation there was a decrease in volume with a higher proportion of cotyledon compared to testa. There was an increase in counts of total mesophiles aerobic microorganisms, molds and yeasts, during the fermentative process.

Poultry Shelf-Life Enhancing Potential of Nanofibers and Nanoparticles Containing Porphyra dioica Extracts

Aqueous extracts of commercially available red macroalgae Porphyra dioica were integrated as inner coatings of food-grade polypropylene (PP) films through use of electrospinning and electrospraying technologies. Two coating formulations (A = 5 wt% P. dioica extract and 7.5 wt% polyvinyl alcohol (PVA); B = 1 wt% P. dioica extract, 1 wt% PVA, and 17% gelatine) were evaluated as to their capacity to delay spoilage of minced chicken breasts, through monitoring of microbial growth (total mesophile aerobic colony counts), colour stability, lipid oxidation (thiobarbituric acid reactive substances (TBARS)), and sensory analysis over a 4-day refrigerated storage. Scanning electron microscopy (SEM) imaging revealed an increased nanofiber and nanoparticle density on extract-enriched fibers, without compromise to their morphology or the homogeneity of the coatings. Total microbial counts on coating B samples was significantly (p &lt; 0.001) reduced compared to uncoated plastic wraps. The coated samples also exhibited fewer colour degradation, though the coatings did not differ substantially from uncoated plastic wrap. Sensory analysis test subjects successfully distinguished the raw samples based on their treatment and gave a positive approval rating (66.7%) to the extract-enriched coatings when asked about edibility post storage.

Elaboración de un alimento para ganado bovino a base de zanahoria (&lt;i&gt;Daucus carota&lt;/i&gt; L.) mediante fermentación en estado sólido como una alternativa ecoeficiente

La alimentación del ganado bovino debe basarse en estrategias sostenibles debido a la presión que se ejerce sobre los recursos naturales para la obtención de alimentos concentrados, una de dichas estrategias es la fermentación en estado sólido (FES), la cual, permite diseñar alimentos con menor impacto ambiental, debido a la acción de microorganismos eficientes que enriquecen sustratos con proteína de alto valor biológico. El objetivo de la investigación fue elaborar un alimento mediante FES a base de zanahoria (Daucus carota L.) en mezcla con otros ingredientes como alternativa para la alimentación de ganado, para ello, se obtuvieron tres productos fermentados en estado sólido con la inclusión de zanahoria (FES 1 [control], FES 2 [sin repila de trigo] y FES 3 [sin cascarilla de café]). Se evaluó la variación del pH durante el proceso de fermentación, se hizo análisis composicional y análisis microbiológico de los alimentos. Se obtuvo un aumento de cuatro veces el valor proteico (PB) inicial a las 48 horas pasando de 4,34% a 19% (FES 1), 17,4% (FES 2) y 14,4% (FES 3) (P≤0,05), se observó el mayor crecimiento de mesófilos totales a las 24 horas con 69×10-3 UFC/g (FES 1), 120×10-3 UFC/g (FES 2) y 45×10-3 UFC/g (FES 3) (P≤0,05); el pH descendió a las 96 horas de fermentación desde 5,9 (FES 1), 6,0 (FES 2) y 6,05 (FES 3) a 4,89 (FES 1), 4,91 (FES 2) y 5 (FES 3) (P≤0,05), respectivamente. Se concluye que con el uso de la biotecnología FES es posible utilizar la zanahoria en mezcla con otras materias primas para la obtención de un alimento ecoeficiente para ganado.

Molecular identification and technological characterization of lactic acid bacteria isolated from fermented kidney beans flours (Phaseolus vulgaris L. and P. coccineus) in northwestern Argentina

Legumes are an important protein source in developing countries and their flours represent an attractive alternative for the manufacture of gluten free products. In the present study, 4 kidney bean varieties (Alubia, Pallar, Black and Red beans) commonly cultivated in northwestern Argentina, were milled and spontaneously fermented in order to isolate and select autochthonous lactic acid bacteria (LAB) with relevant technological and functional properties for usage as starter cultures. Twelve doughs were fermented with daily back-slopping at 37°C for 6days and evolution of total mesophiles, lactic acid bacteria, and yeasts and molds populations were followed by plate counting. A combination of phenotypic and genotypic methods including (GTG)5-based PCR fingerprinting and 16S rRNA gene sequencing were used to differentiate and identify the isolated LAB to species level. LAB counts ranged from around 0.89±0.81 to 8.74±0.03logcfu/g with a pH decline from 6.4 to 3.9 throughout fermentation. Four genera and nine species of LAB: Enterococcus durans, E. faecium, E. mundtii, E. casseliflavus; Lactobacillus rhamnosus, Lactococcus garvieae, Weissella cibaria and W. paramesenteroides were found on kidney beans. Twenty five LAB strains were assessed for their abilities to grow on kidney bean extracts, acidifying capacities (pH and acidification rates), amylolytic, proteolytic, tannase and gallate decarboxylase activities as well as pathogens inhibition by antimicrobials. Based on these properties E. durans CRL 2178 and W. paramesenteroides CRL 2182 were inoculated singly and combined in Alubia kidney bean flour and fermented for 24h at 37°C. LAB strains were beneficial for removing trypsin inhibitors and tannins from sourdoughs and for improving amino acids and phenolics contents, increasing the antioxidant activities of kidney bean matrices. Selected strains have potential as starter cultures for obtaining fermented bean products with high nutritional and functional quality.

Effects of chitosan coating and rosemary oil on rainbow trout(Oncorhynchus mykiss, W. 1792) filets

This study was performed to examine the effect of chitosan and rosemary oil on the shelf life changes of the rainbow trout filet. The samples divided into 4 groups. The control (I) group samples nothing were applied. The group II samples were applied solution of 2% chitosan. The group III samples were applied 2% chitosan and 0.05% rosemary oil and group IV samples only 0.05% rosemary oil. The samples of all groups storage at +4 °C for day 20. The microbiological (total mesophilemesophiles aerobe bacteria, H2S producing bacteria, Enterobacteria, Pseudomonas spp. and lactic acid bacteria), chemical (pH, total volatile base nitrogen and thiobarbituric acid) and sensory evaluation on days 0, 4, 8, 12, 16 and 20. Total mesophile aerobe bacteria count reached 7.2 log10 cfu/g at samples of group I on 8 day, while 4 log10 cfu/g samples of group III on 20 day. The result of chemical parameters, samples of group III were detected better than other groups samples during the storage time.