Influence of probiotic cultures addition on the properties of semi-hard ewe’s cheese

Dodatak probiotičkih bakterija u fermentirane mliječne napitke bio je predmet mnogih istraživanja, međutim dodatak tih bakterija u sireve, posebno one proizvedene od ovčjeg mlijeka, nije do sada detaljno istražen. Stoga su u ovom radu proizvedeni probiotički polutvrdi ovčji sirevi s dodatkom probiotika Bifidobacterium animalis subsp. lactis BB-12 i Lactobacillus acidophilus LA-5. Zrenje sireva se odvijalo 45 dana pri 13 °C i 85 % relativne vlažnosti. Tijekom tog razdoblja određivani su kemijski parametri i provedene su mikrobiološke analize proizvedenih probiotičkih sireva. Dodatak probiotičkih kultura nije značajno utjecao na kemijska i mikrobiološka svojstva proizvedenih sireva u usporedbi s kontrolnim sirevima bez dodatka probiotičkih kultura. Broj živih probiotičkih bakterija održao se na ca 106-107 CFU/g probiotičkih sireva tijekom 45 dana zrenja, što je potvrđeno RAPD metodom. Probiotički polutvrdi ovčji sirevi s bakterijom Bifidobacterium animalis subsp. lactis BB-12 su imali slična senzorska svojstva sirevima proizvedenim bez dodatka probiotika, dok je dodatak bakterije Lactobacillus acidophilus LA-5 doveo do poboljšanja okusa polutvrdog ovčjeg sira. Dobiveni rezultati pokazuju da je polutvrdi ovčji sir pogodan matriks za primjenu probiotičkih kultura Bifidobacterium animalis subsp. lactis BB-12 i Lactobacillus acidophilus LA-5.Addition of probiotic bacteria into fermented milk beverages has been the subject of many studies, however, addition of these bacteria into cheeses, especially the ones made from ewe’s milk, has not been thoroughly investigated. Therefore, the aim of this study was to produce probiotic semi-hard ewe’s cheese with addition of probiotic strain Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus acidophilus LA-5. Cheese ripening occurred during 45 days at 13 °C and 85 % of relative humidity. During that period, chemical parameters were determined and microbiological analysis of manufactured probiotic cheeses was performed. Addition of probiotic cultures did not significantly influence the chemical properties and microbiological quality of produced cheeses in comparison with the control cheeses without addition of probiotic cultures. Number of live probiotic bacteria remained at about 106-107 CFU/g of probiotic cheeses during 45 days of ripening, which was confirmed by RAPD method. Sensory properties of probiotic semi-hard ewe’s cheese with Bifidobacterium animalis subsp. lactis BB-12 were similar to those obtained for cheeses without addition of probiotic, while addition of Lactobacillus acidophilus LA-5 improved the taste of cheeses. Obtained results demonstrated that semi-hard ewe’s cheese can be an effective matrix for addition of probiotic cultures Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus acidophilus LA-5

Influencia del contenido graso y de otras variables sobre la capacidad de fusión del queso Cremoso Argentino

The influence of the fat content, pH, the ripening degree and the incorporation of whey proteins, by two different methods, on the meltability of Cremoso Argentino cheese was examined. Different experimental cheeses were made at pilot plant scale and their meltabilities were determined by a modified Schreiber test. Ripening degree and fat content showed a good correlation with the meltability. Though, cheeses with incorporation of whey proteins showed poor meltability, despite their yields increased. No correlation was found between pH and meltability inside the pH working range studied.En el presente trabajo se estudió la influencia del contenido de materia grasa, pH, grado de maduración e incorporación de proteínas de suero mediante dos vías diferentes sobre la capacidad de fusión del queso Cremoso Argentino. Utilizando una técnica modificada del test de Schreiber se analizó la capacidad de fusión de distintos quesos experimentales elaborados a escala piloto. El contenido graso y el grado de maduración afectaron positivamente la capacidad de fusión. La incorporación de proteínas de suero produjo mayores rendimientos pero la capacidad de fusión se vio fuertemente disminuida. No se observó una influencia clara del pH dentro de los límites estudiado

Characterisation of Proteolysis Profile of Argentinean Sheep Cheeses Made by Two Different Production Methods

U radu su proučeni profili proteolize u argentinskom ovčjem siru napravljenim dvjema metodama proizvodnje kako bi se dobile tipične i definirane karakteristike. Proizvedeni su sirevi s mikrobnom kulturom Streptococcus thermophilus (S-sirevi) i sirevi s miješanom mikrobnom kulturom Streptococcus thermophilus i Lactobacillus bulgaricus (L-sirevi). Sirevi su dozrijevali na 12oC i 80% relativne vlažnosti kroz 180 dana i uzorci su uzimani tijekom tog vremenskog razdoblja. Rezultati pokazuju određene sličnosti ali i razlike, posebice u pH vrijednosti, dok je senzorska analiza pokazala bitne razlike između te dvije vrsta sireva. S-sirevi imaju niži stupanj proteolize i blaži okus, što ih čini prikladnim za konzumaciju nakon kratkog vremena dozrijevanja. L-sirevi imaju viši stupanj proteolize, te puno izraženija senzorska svojstva, što ih čini prikladnim za konzumaciju nakon duljeg vremena dozrijevanja.In this work the proteolysis profile of Argentinean sheep cheeses made by two production methods were studied in order to develop products with typical and defined features. Cheeses with a starter of Streptococcus thermophilus, (S-cheeses) and cheeses with a mixed starter of Streptococcus thermophilus and Lactobacillus bulgaricus, (L-cheeses) were manufactured. The cheeses were ripened at 12oC and 80% relative humidity for 180 days and samples were taken throughout this period. Results show similarities but also some differences, especially in pH value, while sensory evaluation indicated important differences between the two types of cheeses. S-cheeses had a low proteolysis and soft flavor, making them appropriate for consumption after a short ripening time. L-cheeses had a higher proteolysis level and more intense sensory characteristics, making them appropriate for consumption after a longer ripening time

Suitability of buttermilk for fermentation with Lactobacillus helveticus and production of a functional peptide-enriched powder by spray-drying

Aim: To ferment buttermilk, a low-cost by-product of the manufacture of butter, with a proteolytic strain of Lactobacillus helveticus, to enhance its value by the production of a functional peptide-enriched powder. Methods and Results: Buttermilk was fermented with Lact. helveticus 209, a strain chosen for its high proteolytic activity. To enhance the release of peptidic fractions, during fermentation pH was kept at 6 by using NaOH, Ca(CO)3 or Ca(OH)2. Cell-free supernatant was recovered by centrifugation, supplemented or not with maltodextrin and spray-dried. The profile of peptidic fractions released was studied by RP-HPLC. The lactose, Na and Ca content was also determined. The powder obtained was administered to BALB ⁄ c mice for 5 or 7 consecutive days, resulting in the proliferation of IgA-producing cells in the small intestine mucosa of the animals. Conclusions: Buttermilk is a suitable substrate for the fermentation with Lact. helveticus 209 and the release of peptide fractions able to be spray-dried and to modulate the gut mucosa in vivo. Significance and Impact of the Study: A powder enriched with peptides released from buttermilk proteins, with potential applications as a functional food additive, was obtained by spray-drying. A novel use of buttermilk as sub- strate for lactic fermentation is reported.Fil: Burns, Patricia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Molinari, F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Beccaria, A.. Universidad Nacional del Litoral; ArgentinaFil: Paez, Roxana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Meinardi, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Reinheimer, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Vinderola, Celso Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentin

Environmentally friendly luminescent solar concentrators based on an optically efficient and stable green fluorescent protein

Luminescent solar concentrators (LSCs) are a solution to overcome the mismatch between solar cell absorption and the solar spectrum, facilitating the integration of photovoltaic (PV) devices into the urban environment, since they can be incorporated in building façades and windows. Challenges include the search for environmentally friendly materials with chemical and optical stabilities. The enhanced green fluorescent protein (eGFP) was efficiently applied as an optically active center. eGFP absorbs in the UV/visible range and converts it into green emission with a maximum absolute quantum yield of ∼0.50. Here, we report the use of eGFP to fabricate planar LSCs in the liquid (aqueous solution) and solid state (incorporated in organic-inorganic hybrids), which were coupled to commercial Si-based PV cells yielding power conversion efficiency values of up to ∼0.35%. These results are higher than the figures of merit for naturally-based fluorescent proteins in aqueous media, with the advantage of presenting enhanced photostability when stored under ambient conditions. These are relevant features, uncommon in organic-based materials, which significantly contribute to the potential of naturally-based molecules in the development of LSCs as reliable, sustainable and competitive energy systems.publishe

Global airborne sampling reveals a previously unobserved dimethyl sulfide oxidation mechanism in the marine atmosphere

6 pags., 5 figs.Dimethyl sulfide (DMS), emitted from the oceans, is the most abundant biological source of sulfur to the marine atmosphere. Atmospheric DMS is oxidized to condensable products that form secondary aerosols that affect Earth’s radiative balance by scattering solar radiation and serving as cloud condensation nuclei. We report the atmospheric discovery of a previously unquantified DMS oxidation product, hydroperoxymethyl thioformate (HPMTF, HOOCH2SCHO), identified through global-scale airborne observations that demonstrate it to be a major reservoir of marine sulfur. Observationally constrained model results show that more than 30% of oceanic DMS emitted to the atmosphere forms HPMTF. Coincident particle measurements suggest a strong link between HPMTF concentration and new particle formation and growth. Analyses of these observations show that HPMTF chemistry must be included in atmospheric models to improve representation of key linkages between the biogeochemistry of the ocean, marine aerosol formation and growth, and their combined effects on climate.Additional National Oceanic and Atmospheric Administration (NOAA) support for ATom was provided by NASA funding via Inter-Agency Transfer NNH15AB12l and by funding from the NOAA Climate Program Office and the NOAA Atmospheric Chemistry, Carbon Cycle, and Climate program. K.H.M. and H.G.K. acknowledge the financial support of the Independent Research Fund Denmark, the University of Copenhagen, and the Danish Ministry for Higher Education and Science’s Elite Research travel grant. J.L.J.’s group acknowledges NASA grants NHX15AH33A and 80NSSC19K0124. A.K. was supported by the Austrian Science Fund’s Erwin Schrodinger Fellowship. A.S.-L., Q.L., and C.A.C. are supported by the European Research Council (ERC) Executive Agency under the European Union’s Horizon 2020 Research and Innovation programme (Project ERC-2016-COG 726349 CLIMAHAL). The National Center for Atmospheric Research is sponsored by the National Science Foundation. E.A. and J.B. were funded in part by NASA Atmospheric Composition Program. T.H.B. and C.M.J. acknowledge support from the National Science Foundation Center for Aerosol Impacts on Chemistry of the Environment under grant CHE 1801971. B.W. and M.D. have received funding from the ERC under the European Union’s Horizon 2020 research and innovation framework program under grant 640458 (A-LIFE) and from the University of Vienna.Peer reviewe