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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Seleção e aplicação de bactérias láticas produtoras de folato para obtenção de um leite fermentado bioenriquecido e avaliação de biodisponibilidade do folato produzido. / Screening and application of folate-producing lactic acid bacteria for production of bioenriched fermented milk and evaluation of the bioavaliability of the produced folate

Cucick, Ana Clara Candelaria 17 July 2019 (has links)
A deficiência de folato é um problema de saúde pública que vem sendo combatido através da fortificação obrigatória de ácido fólico. Entretanto, a ingestão excessiva pode causar efeitos colaterais indesejados. A forma natural da vitamina produzida por algumas cepas de bactérias láticas pode ser uma alternativa segura para aumentar a ingestão de folato pela população. Este trabalho visou selecionar as melhores cepas de BAL produtoras de folato, identificar as melhores condições para a produção da vitamina e avaliar a biodisponibilidade do folato produzido pelas cepas no leite fermentado, empregando-se testes em modelos animais. O estudo foi desenvolvido com cinco cepas de Streptococcus thermophilus (34v, 170v, 268v, 361v e 341 pc) e um cepa de Lactobacillus plantarum (16cv), todas boas produtoras de folato. As condições de produção e a combinação de cepas que resultaram na melhor produção folato foram utilizadas para produzir um leite biofermentado (BFM), avaliando-se a biodisponibilidade da vitamina produzida empregando-se um modelo animal de depleção/repleção, com camundongos Balb/c submetidos a 14 dias de depleção, seguido de 21 dias de repleção da vitamina. Após os 35 dias, os animais foram sacrificados, retirando-se sangue, rins, fígado, baço e intestino para quantificação de folato e avaliação histológica da mucosa intestinal. Todas as quantificações de folato foram feitas pelo método microbiológico. A melhor combinação de cepas (St. Thermophilus 34v + Lb. Plantarum 16cv) resultou na produção de 300 ng/mL de folato, sendo a temperatura de 42ºC melhor que 37ºC para a produção da vitamina. A produção de folato no leite na fermentação em pH controlado 6,0 foi 35% superior à observada no leite fermentado em pH livre. As concentrações de folato no baço e glóbulos vermelhos foram mais altas nos camundongos que ingeriram leite fermentado bioenriquecido (BFM) em relação aos demais grupos de animais. A relação vilosidade/cripta nos camundongos dos grupos BFM foi igual à observada nos animais que receberam leite suplementado com ácido fólico. Houve aumento da hemoglobina, hematócrito e hemácias nos camundongos que ingeriram BFM, evidenciando a bioeficácia do folato produzido. Esses resultados indicam que a produção de folato por bactérias láticas selecionadas em produtos fermentados pode ser uma boa alternativa para aumentar a ingestão de vitamina B9 pela população. / Folate deficiency is a public health problem that has been tackled through mandatory fortification of folic acid. However, excessive intake can cause unwanted side effects. The natural form of the vitamin produced by some strains of lactic acid bacteria (BAL) may be a safe alternative to increase folate intake by the population. The objective of this study was to select the best folate-producing BAL strains, to identify the best conditions for vitamin production and to evaluate the bioavailability of folate produced by the strains in fermented milk, using tests in animal models. The study was carried out with five strains of Streptococcus thermophilus (34v, 170v, 268v, 361v and 341 pc) and a strain of Lactobacillus plantarum (16 cv), all good folate producers. The conditions of production and the combination of strains that resulted in the best folate production were used to produce a biofermented milk (BFM), evaluating the bioavailability of the vitamin produced using a animal model of depletion/repletion with Balb/c mice submitted to 14 days of vitamin depletion, followed by 21 days of repletion. After 35 days, the animals were sacrificed, and blood, kidneys, liver, spleen and intestine were removed for quantification of folate and histological evaluation of the intestinal mucosa. All quantifications of folate were made by the microbiological method. The best combination of strains (St. thermophilus 34v + Lb. plantarum 16cv) resulted in the production of 300 ng / mL folate, the temperature being 42ºC better than 37ºC for vitamin production. The production of folate in milk in fermentation at controlled pH 6.0 was 35% higher than that observed in fermented milk without pH control. The villi/crypt ratio in the mice of the BFM group was the same as in animals receiving milk supplemented with folic acid. There was an increase in hemoglobin, hematocrit and red blood cells in the BFM group, evidencing the bioefficacy of the folate produced. These results indicate that folate production by selected lactic bacteria in fermented products may be a good alternative to increase vitamin B9 intake by the population.
42

Identification and properties of potential probiotic bacteria for application in Mageu.

Nyanzi, Richard. January 2013 (has links)
D. Tech. Food Technology. / Discusses a range of lactobacilli and bifidobacteria were isolated from functional food products and pharmaceutical preparations and also obtained from culture collections. They were then subjected to phylogenetic analysis for accurate identification and classification and the probiotic properties of the organisms was evaluated. The isolates were then screened for inhibitory activity against a range of pathogenic bacteria and Candida albicans strains. Selected isolates that were found to have the necessary inhibitory and probiotic properties were recommended for inclusion in an envisaged synbiotic, maize-based beverage that would, in a subsequent study, be subjected to a nutritional intervention trial aimed at alleviating oral thrush in human patients. The specific objectives: to investigate and illustrate the superiority of rpoA and pheS gene sequencing compared to 16S rRNA gene sequencing in the identification and phylogenic assignment of Lactobacillus isolates ; to determine the precision of selected protein-coding gene sequencing in comparison with 16S rRNA gene sequencing for the discrimination and phylogenetic analysis of Bifidobacterium isolates ; to investigate the probiotic properties of selected bacterial strains in terms of antibacterial activity, anti-Candida activity, acid resistance, bile tolerance and antibiotic resistance ; to determine the potential of Lactobacillus isolates to inhibit the growth of each of seven Candida albicans strains in fermented maize gruel and to establish the factors contributing to Candida inhibition and to determine the antimicrobial and antioxidant activity of intracellular extracts and to elucidate compounds in methanol extracts from selected Lactobacillus strains.
43

The inhibitory activity and sensory properties of kefir, targeting the low-income African consumer market

Van Wyk, Juliette 12 1900 (has links)
Thesis (MSc Food Sc )--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The rapid urbanisation of the African population has led to the establishment of large low-income communities in and around almost every major town and city in South Africa. Several factors prevent these people from producing or obtaining their traditional fermented milk drink, Maas (Amasi), often resulting in the occurrence of malnutrition in low-income urban African communities. A product with the potential to satisfy the demand for a fermented milk product is Kefir. Kefir, a self-carbonated fermented milk, is commonly manufactured by fermenting unpasteurised or pasteurised milk with re-usable Kefir grains. These Kefir grains consist of a combination of mainly lactic acid bacteria and yeasts. Neither Kefir, nor Kefir grains are as yet marketed in South Africa, thus creating an excellent opportunity to launch these products locally. It is often difficult for the low-income communities to obtain high quality unpasteurised or pasteurised milk, resulting in a serious health risk. The inhibitory activity of Kefir towards certain spoilage and pathogenic microorganisms was, therefore, studied. Strains of Escherichia coli, Staphylococcus aureus, Bacillus cereus, Usteria monocytogenes and Clostridium tyrobutyricum were inoculated (10 ³ - 10 ⁴ cfu.ml⁻¹ ) into pasteurised milk together with Kefir grains (18 gram per litre) and incubated at 25°C. Uninoculated milk samples and milk samples inoculated only with test organisms served as controls. Growth of all the test organisms were inhibited substantially (>-99.9%) in Kefir over the 30 h incubation period and substantial reductions in microbial log cycles were observed for many of the organisms. This coincided with a steep decrease in pH (6.57 - 4.06) and increase in titratabie acidity (0.20 - 0.72%). If Kefir is eventually marketed to low-income urban African consumers, it will have to compete with Maas and, therefore, comparative sensory testing of Kefir and Maas was conducted. The differences in the sensory properties of Kefir, 'laboratory' Maas (representing traditional Maas) and commercial Maas (containing thickener, colourants and flavourants) were determined by a trained panel. These characteristics were identified as "yeasty" and "cowy" tastes (p < 0.05), "effervescence" (p < 0.01), as well as "sourness," "creaminess" and "smoothness" (p < 0.001). The effect of different incubation temperatures (25°, 30° and 35°C) on the Kefir sensory properties was studied to simulate the effect of the large temperature variations that would be found in the dwellings of low-income African urbanites. The "sourness" and "creaminess" of the Kefir was found to increase with increase in incubation temperature but no strong off-flavours were found to develop. Sensory preference testing was conducted by consumer panels consisting of panellists of different ages and population groups to indicate whether the specific panels significantly prefer Kefir, commercial Maas or laboratory Maas. It was found that commercial Maas was significantly (p < 0.001) preferred to Kefir by young African urbanites. Adult Africans, who presumably still have traditional taste preferences, however, equally (p > 0.05) preferred Kefir and laboratory Maas, identifying this segment of the African population as the appropriate starting target market for Kefir. Kefir and laboratory Maas were also tested for preference by a wider panel consisting of people (aged between 18 and 25) representing the different population groups in South Africa. Kefir and laboratory Maas were preferred equally (p > 0.05) by all the groups. Several arguments supporting Kefir marketing to the low-income urban African population of South Africa have been identified. These include: Kefir's ease of preparation; the re-usability of Kefir grains and subsequent affordability; good packaging, distribution and storage possibilities; Kefir's acceptability by lactoseintolerant individuals; high nutritional value; the inhibitory activity of Kefir against potential spoilage and pathogenic organisms and subsequent enhanced safety and keeping ability; and Kefir's acceptable refreshing taste. / AFRIKAANSE OPSOMMING: Die toenemende verstedeliking van Swart Suid-Afrikaners het gelei tot die vestiging van groot lae-inkomste gemeenskappe in en om die meeste groot dorpe en stede. Verskeie faktore verhoed dat hierdie gemeenskappe hul tradisionele gefermenteerde melk, naamlik Maas (Amasi), self kan maak of koop. Dit lei dikwels tot wanvoeding onder lae-inkomste stedelike Swart verbruikers. Kefir het die potensiaal om te voorsien in die vraag na 'n gefermenteerde melk produk in lae inkomste stedelike Swart gemeenskappe. Kefir is 'n selfgekarboneerde, gefermenteerde melk wat vervaarding word deur die fermentasie van ongepasteuriseerde of gepasteuriseerde melk met herbruikbare Kefirkorrels. Hierdie Kefirkorrels bestaan uit 'n kombinasie van hoofsaaklik melksuurbakterieë en giste. Kefir en Kefirkorrels word glad nie in Suid-Afrika bemark nie, en bied 'n fantastiese geleentheid om hierdie produkte plaaslik bekend te stel. Dit is dikwels moeilik om hoë kwaliteit ongepasteuriseerde of gepasteuriseerde melk in lae-inkomste gemeenskappe te verkry. Die risiko om siektes deur die verbruik van hierdie melk op te doen, bestaan dus. Om hierdie rede is die inhiberende effek van Kefir teenoor spesifieke bederf- en patogeniese bakterieë bestudeer. Rasse van Escherichia coli, Staphylococcus aureus, Bacillus cereus, Usteria monocytogenes en Clostridium tyrobutyricum is geïnokuleer (10 ³ - 10 ⁴ cfu.ml⁻¹) in gepasteuriseerde melk tesame met Kefirkorrels (18 gram per liter) en geïnkubeer by 25°C. Melkmonsters wat slegs geïnokuleer is met die toetsorganismes het as kontroles gedien. Die groei van al die toetsorganismes is substansieël geïnhibeer (>-99.9%) in Kefir gedurende die 30 h inkubasieperiode. Substansiële afnames in logsiklusgetalle is waargeneem vir baie van die organismes. Dit het gepaard gegaan met 'n skerp afname in pH (6.57 - 4.06) en toename in titreerbare suurheid (0.20 - 0.72%) vir die Kefirmonsters gedurende die 30 h inkubasieperiode. lndien Kefir bemark word aan lae-inkomste stedelike Swart verbruikers sal dit moet kompeteer met Maas. Vergelykende sensoriese toetse is dus uitgevoer. Die verskille in die sensoriese eienskappe van Kefir, 'laboratorium' Maas (verteenwoordigend van tradisionele Maas) en kommersiële Maas (wat verdikker, kleur- en geurmiddels bevat) is bepaal deur 'n opgeleide paneel en geïdentifiseer as die" "gis-" en "koeismake" (p < 0.05), die "gasserigheid" (p < 0.01) asook die "suurheid", "romerigheid" en "gladheid" (p < 0.001) van die monsters. Die effek van verskillende inkubasietemperature (25°, 30° en 35°C) op die sensoriese eienskappe van Kefir is bestudeer om die effek van die groot temperatuurvariasies wat in laeinkomste behuising mag voorkom, te simuleer. Daar is bevind dat die "suurheid" en "romerigheid" van Kefir toeneem met verhoging in inkubasietemperatuur terwyl geen afsmake ontwikkel nie. Sensoriese voorkeurtoetse is deur verbruikerspanele van verskillende ouderdomme en bevolkingsgroepe uitgevoer om te bepaal of die spesifieke panele 'n beduidende voorkeur toon vir Kefir, laboratorium Maas of kommersiële Maas. Daar is bevind dat stedelike Swart jongmense kommersiële Maas beduidend (p < 0.001) bo Kefir verkies. Swart volwassenes met verwagte tradisionele smaakvoorkeure het egter Kefir en laboratorium Maas ewe veel verkies (p > 0.05). Hierdie segment van die Swart bevolking is dus die geskikte teikenmark vir die bekendstelling van Kefir. Voorkeur vir Kefir en laboratorium Maas is ook getoets deur 'n paneel (ouderdom 18 - 25 jaar) wat bestaan uit mense van verskillende bevolkingsgroepe. AI die groepe het Kefir en Maas ewe veel verkies (p > 0.05). Verskeie argumente ten gunste van die bemarking van Kefir aan lae-inkomste stedelike Swart gemeenskappe in Suid-Afrika is geïdentifiseer. Dit behels die volgende: die gerief van Kefirvervaardiging; die herbruikbaarheid van Kefirkorrels en gevolglike bekostigbaarheid; goeie verpakkings-, verspreidings- en opbergingsmoontlikhede; Kefir se aanvaarbaarheid vir laktose-intolerante individue; Kefir se hoë voedingswaarde; die inhiberende aktiwiteit wat Kefir teenoor potensiële bederf- en patogeniese organismes het en die gevolglike verhoging in veiligheid en rakleeftyd van melk; en Kefir se aanvaarbare verfrissende smaak.
44

Isolation and identification of the microbial consortium present in fermented milks from Sub-Saharan Africa

Schutte, Lionie Marie 03 1900 (has links)
Thesis (MSc Food Sc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: A wide variety of traditionally and commercially fermented milks are commonly consumed in various countries of Sub-Saharan Africa. Commercially fermented milk is produced on an industrial scale according to well-managed, standardised production processes and starters are used to initiate fermentation. Traditionally fermented milk is prepared domestically and fermentation occurs spontaneously at ambient temperatures. Lactic acid bacteria (LAB) are responsible for milk fermentation during which they convert the milk carbohydrates to lactic acid, carbon dioxide, alcohol and other organic metabolites. Acetic acid bacteria (AAB), yeasts and mycelial fungi have also been isolated from fermented milks. In this study the microbial consortium present in three traditionally fermented milks, namely omashikwa from Namibia, masse from Mozambique and chekapmkaika from Uganda and two commercially fermented milks, namely chambiko from Malawi and omaere from Namibia, were isolated and enumerated on six different selective media that included MSR + C (specific for lactobacilli), KCA + TTC (specific for lactococci), KCA + V (specific for leuconostocs), MRS + E (specific for AAB), MEA (specific for mycelial fungi) and YPD (specific for yeasts). No significant differences were found between the enumeration values obtained for the three chambiko samples, as well as for enumeration values obtained for the two omaere samples on each of the selective media, indicating low sample variance. Significant differences between enumeration values obtained for the three omashikwa samples were found on all six selective media. Significant differences between enumeration values of the three masse samples and both the chekapmkaika samples were also observed on the selective media. In addition to this, significant differences were observed between average enumeration values obtained for each media between the masse and chekapmkaika, the chambiko and omaere, as well as when the traditional and commercial milks were compared. According to the average enumeration values obtained on each media selective for LAB, the highest bacterial counts were detected on KCA + TTC medium for omaere (2.3 x 106 cfu.ml-1), KCA + V for chambiko (1.8 x 105 cfu.ml-1), KCA + TTC for omashikwa and MRS + C for masse and chekapmkaika (6.2 x 106 and 2.0 x 103 cfu.ml-1, respectively). After isolation and enumeration of the microbes present in each milk, bacterial isolates on the media selective for LAB and AAB were obtained according to the Harrison Disk method. These isolates were identified by amplifying a 1.5 kilobase (kb) part of the 16S ribosomal RNA (rRNA) gene using the polymerase chain reaction (PCR), followed by DNA sequencing. The isolates were identified by comparing the sequences obtained to sequences listed in the NCBI database using the BLAST algorithm and searching for the closest relative. The main LAB group present in the omaere was lactococci (94%), in chambiko and chekapmkaika it was lactobacilli (30% and 45%, respectively), in omashikwa it was enterococci (43%) and in masse it was leuconostocs (68%). The same microbial species were present on a number of the selective media used in this study. Lactococcus spp., Enterococcus spp. and Lactobacillus spp. were isolated from MRS + C, KCA + TTC, KCA + V and MRS + E and Leuconostoc spp. were isolated from MRS + C, MRS + E and KCA + V. Hygienic standards during traditional milk fermentation is often poor and, therefore, microbial contaminants were isolated from the traditional milk and these included Acinetobacter johnsonii and Klebsiella pneumoniae from KCA + V, Mesorhizobium loti, Acinetobacter radioresistens, Escherichia coli, Staphylococcus spp., Kluyvera georgiana, Enterobacter spp. and Klebsiella oxytoca from KCA + TTC, Staphylococcus spp. from MRS + C and Bacillus spp. from MRS + E. Since the media used for the isolation of the LAB and AAB in this study were not selective further identification of the enumerated microbes is of importance for the identification of the microbial groups present in each fermented milk. The data obtained in this study clearly shows that fermented milks from Sub-Saharan Africa vary significantly from each other in terms of microbial numbers, microbial diversity and the dominant microbial groups present. The microbial diversity of the traditionally fermented milks was more diverse than the microbial diversity of the commercially fermented milks. LAB strains isolated from these traditionally fermented milks can be used to develop novel starters and as a result new commercially fermented dairy products with unique aromas, tastes and characteristics can be produced. / AFRIKAANSE OPSOMMING: 'n Wye verskeidenheid tradisioneel en kommersieel gefermenteerde melk produkte word algeneem verbruik in verskeie lande van Sub-Sahara Afrika. Kommersieel gefermenteerde melk word geproduseer op groot skaal, deur deeglik bestuurde gestandardiseerde produksieprosesse en 'n beginkultuur word gebruik om fermentasie te inisieer. Tradisioneel gefermenteerde melk word tuis gemaak en fermentasie gebeur spontaan by kamertemperatuur. Melksuurbakterieë (MSB) is verantwoordelik vir melkfermentasie waartydens die bakterieë koolhidrate omskakel na melksuur, koolstofdioksied, alkohol en ander organiese sure. Asetaatsuurbakterieë (ASB), giste en miseliale fungi is ook al van gefermenteerde melk geïsoleer. In hierdie studie is die mikrobiese konsortium teenwoordig in drie soorte tradisioneel gefermenteerde melk, naamlik omashikwa van Namibië, masse van Mosambiek en chekapmkaika van Uganda en twee soorte kommersieel gefermenteerde melk, naamlik chambiko van Malawi en omaere van Namibië, geïsoleer en getel op ses verskillende selektiewe groeimedia insluitend MRS + C (spesifiek vir lactobacilli), KCA + TTC (spesifiek vir lactococci), KCA + V (spesifiek vir leuconostocs), MRS + E (spesifiek vir ASB), MEA (spesifiek vir miseliale fungi) en YPD (spesifiek vir giste). Geen betekenisvolle verskille is gevind tussen die mikrobiese tellings verkry vir die drie chambiko monsters nie, sowel as tussen die mikrobiese tellings verkry vir die twee omaere monsters, op elk van die selektiewe groeimedia, wat dui op lae monster variansie. Betekenisvolle verskille is gevind tussen die mikrobiese tellings verkry vir die drie omashikwa monsters op al ses selektiewe groeimedia. Betekenisvolle verskille is ook waargeneem tussen die mikrobiese tellings van die drie masse monsters en beide die chekapmkaika monsters op die selektiewe groeimedia. Daarbenewens is betekenisvolle verskille waargeneem tussen gemiddelde mikrobiese tellings verkry vir elke groeimedium tussen die masse en chekapmkaika, die chambiko en omaere asook toe die tradisionele en kommersiële melk produkte met mekaar vergelyk is. Volgens die gemiddelde mikrobiese tellings verkry op elk van die groeimedia selektief vir MSB, is die hoogste mikrobiese telling waargeneem op KCA + TTC medium vir omaere (2.3 x 106 kve.ml-1), KCA + V vir chambiko (1.8 x 105 kve.ml-1), KCA + TTC vir omashikwa en MRS + C vir masse en chekapmkaika (6.2 x 106 en 2.0 x 103 kve.ml-1, respektiewelik). Na die isolasie en tel van die mikrobes teenwoordig in elke melk is bakteriese isolate op die media selektief vir MSB en ASB verkry volgends die Harrison Disk metode. Hierdie isolate is geïdentifiseer deur amplifikasie van „n 1.5 kilobasis (kb) gedeelte van die 16S ribosomale RNS (rRNS) geen deur gebruik te maak van die polimerase kettingreaksie gevolg deur DNS klonering. Die isolate is geïdentifiseer deur die gekloneerde insetsels se volgordes te vergelyk met volgordes beskikbaar op die NCBI webwerf deur van die BLAST algoritme gebruik te maak en die naas verwante insetsel op te spoor. Die hoof MSB groep teenwoordig in die omaere was lactococci (94%), in chambiko en chekapmkaika was dit lactobacilli (30% en 45%, respektiewelik), in die omashikwa was dit enterococci (43%) en in die masse was dit leuconostocs (68%). Dieselfde mikrobiese spesies was teenwoordig op verskeie van die selektiewe groeimedia gebruik in hierdie studie. Lactococcus spp., Enterococcus spp. en Lactobacillus spp. is geïsoleer van MRS + C, KCA + TTC, KCA + V en MRS + E en Leuconostoc spp. is geïsoleer van MRS + C, MRS + E en KCA + V. Higiëniese standaarde tydens tradisionele melkfermentasie is dikwels swak en dus is mikrobiese kontaminante geïsoleer van die tradisionele melk produkte insluitend Acinetobacter johnsonii en Klebsiella pneumoniae van KCA + V, Mesorhizobium loti, Acinetobacter radioresistens, Escherichia coli, Staphylococcus spp., Kluyvera georgiana, Enterobacter spp. en Klebsiella oxytoca van KCA + TTC, Staphylococcus spp. van MRS + C en Bacillus spp. van MRS + E. Aangesien die media wat gebruik is vir die isolasie van die MSB en ASB in hierdie studie nie selektief was nie, is verdere identifikasie van die getelde mikrobes belangrik vir die identifikasie van die mikrobiese groepe teenwoordig in elke melk. Die data verkry in hierdie studie dui aan dat gefermenteerde melk produkte van Sub-Sahara Afrika betekenisvol van mekaar verskil in terme van mikrobiese getalle, mikrobiese diversiteit en die dominante mikrobiese groepe teenwoordig. Die mikrobiese diversiteit van die tradisioneel gefermenteerde melk produkte was meer divers as die mikrobiese diversiteit van die kommersieel gefermenteerde melk produkte. MSB spesies geïsoleer van hierdie tradisioneel gefermenteerde melk produkte kan gebruik word om nuwe beginkulture te ontwikkel en gevolglik kan nuwe kommersieel gefermenteerde suiwelprodukte met unieke aromas, smake en eienskappe geproduseer word.
45

Qualidade de produtos lácteos fermentados produzidos no estado da Paraíba

Brasileiro, Jéssica Lisana Ouriques 13 February 2014 (has links)
Made available in DSpace on 2015-04-17T14:49:39Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 942615 bytes, checksum: 7f5e0611dc6b5d3af2061aab6c8cac86 (MD5) Previous issue date: 2014-02-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Yogurt and fermented milk beverages are fermented dairy products that have increased consumption worldwide, and the demand for functional foods spurred the expansion of these products. Thus, it was entended to evaluate the quality of fermented dairy foods produced in the state of Paraíba. Samples of yogurts and milk beverages of the four mesoregions of the state with federal or state registration were performed, the drinks were evaluated on their labeling, microbiological, physical, chemical and rheological properties. Observing the labels, it was found that 89% were in compliance with the legislation, the main irregularities detected were: unauthorized use of additives in the Technical Regulations and the illegibility of the dates of manufacture and validity, which puts at risk consumer health. Although there has been growth of molds and yeasts, 91% of the samples were within the microbiological parameters determined by current legislation. The centesimal composition varied depending on the mesoregion and inspection record. The rheological behavior varied between samples. Was observed relationship between physico-chemical parameters (total solids and protein) and the apparent viscosity. Overall, yogurts and fermented dairy beverages showed satisfactory quality, but should improve labeling requirements, standards of identity and sanitary quality in order to not endanger consumers health, satisfy the increasingly demanding market and to compete with major brands. / Iogurte e bebida láctea fermentada são produtos lácteos fermentados que tem consumo crescente em todo o mundo, e a demanda por alimentos funcionais impulsionou a expansão desses produtos. Assim, pretendeu-se avaliar a qualidade dos alimentos lácteos fermentados produzidos no Estado da Paraíba. Foram realizadas coletas de iogurtes e bebidas lácteas nas quatro mesorregiões do Estado, contendo registro federal ou estadual, as bebidas foram avaliadas quanto à sua rotulagem, características microbiológicas, físicas, químicas e reológicas. Observando os rótulos, verificou-se que 89% estavam em conformidade com a legislação, tendo como principais irregularidades detectadas: uso de aditivos não autorizados nos Regulamentos Técnicos e a ilegibilidade das datas de fabricação e validade, o que põe em risco à saúde dos consumidores. Embora tenha havido crescimento de bolores e leveduras, 91% das amostras mostrou-se dentro dos parâmetros microbiológicos determinados pela legislação vigente. A composição centesimal variou em função da mesorregião e do registro de inspeção. O comportamento reológico variou entre as amostras. Observou-se relação dos parâmetros físico-químicos (sólidos totais e proteína) com a viscosidade aparente. De modo geral, os iogurtes e bebidas lácteas fermentadas apresentaram qualidade satisfatória, porém devem melhorar requisitos de rotulagem, padrões de identidade e qualidade sanitária, a fim de não pôr em risco a saúde dos consumidores, atender o mercado cada vez mais exigente e competir com grandes marcas.
46

Elaboração e avaliação físico-química e microbiológica de produtos lácteos obtidos a base de kefir

Weschenfelder, Simone January 2016 (has links)
A crescente busca por uma alimentação mais saudável e com valor agregado aumenta a necessidade de desenvolvimento de pesquisas que visem não só conhecer os alimentos, como também desenvolver e caracterizar novos produtos. Assim é fundamental que profissionais da área técnica que atuam em indústrias de alimentos e em institutos de pesquisa, trabalhem em conjunto com os profissionais da área da saúde, contribuindo para a prevenção de doenças e promoção da saúde da população. O objetivo geral do estudo foi elaborar e avaliar a atividade antibacteriana in loco de derivados lácteos elaborados a partir de grãos de kefir frente a microrganismos padrão de interesse em alimentos; e determinar a composição físico-química e microbiológica dos produtos. Inicialmente duas formulações de leite fermentado kefir (kefir 1 e 2) foram elaboradas, a primeira com leite pasteurizado e grãos de kefir e a segunda com leite pasteurizado, leite em pó e grãos de kefir. A composição centesimal e de minerais foi avaliada no leite utilizado como matéria-prima e nas formulações de leite fermentado, onde determinou-se também o pH e foi realizada a contagem de bactérias láticas totais. Com base na composição centesimal do kefir, foi verificada a possibilidade de atribuição de propriedade nutricional ao alimento e a conformidade em relação ao regulamento técnico de identidade e qualidade dos leites fermentados. Na sequencia, duas formulações de queijo (Q1 e Q2) e soro (S1 e S2) de kefir foram elaboradas a partir da coagulação microbiana realizada com grãos de kefir e determinada a composição centesimal e o pH. Cinco diferentes densidades populacionais de Staphylococcus aureus (ATCC 25923) e Escherichia coli (ATCC 11229) referidas no estudo como A, B, C, D e E (sendo A > B > C > D > E) foram inoculadas nas formulações de kefir, queijo e soro, sendo determinada a atividade antibacteriana in loco após 0, 24, 48 e 72 horas de confronto. Paralelamente cinco lotes de dez marcas comerciais de leite pasteurizado e leite UHT foram avaliados quanto à conformidade em relação à legislação de rotulagem e aos padrões de identidade e qualidade estabelecidos pela legislação brasileira. As formulações de kefir apresentaram atividade antibacteriana significativa frente às diferentes densidades populacionais dos patógenos em estudo após de 24 horas de exposição, não sendo observada atividade antibacteriana entre 24 e 72 horas de confronto. Kefir 1 e 2 atenderam aos parâmetros físico-químicos e microbiológicos previstos no regulamento técnico de identidade e qualidade de leites fermentados avaliados no estudo. A formulação 1 pode receber a declaração de “fonte de proteínas”, “reduzido em calorias” e “baixo teor de sódio” e a formulação 2 de “alto conteúdo de proteínas”, “baixo teor de sódio” e “alto conteúdo de zinco”. As formulações de queijo e soro de kefir também apresentaram atividade antibacteriana frente aos microrganismos alimentares testados, principalmente após 24 horas de confronto. A atividade antibacteriana foi mais intensa frente à Escherichia coli (ATCC 11229), obtendo-se atividade antibacteriana máxima após 48 e 72 horas de confronto de Q1, Q2, S1 e S2 com diferentes densidades populacionais do microrganismo testadas. As formulações do soro de kefir foram as que apresentaram maior atividade antibacteriana quando comparadas com o kefir e o queijo. Todas as marcas comerciais de leite avaliadas estavam em conformidade com a legislação brasileira de rotulagem. Uma marca de leite pasteurizado integral e três marcas de leite UHT integral não atenderam aos parâmetros mínimos de identidade e qualidade em pelo menos dois dos cinco lotes avaliados, apontando falhas no processo de beneficiamento. Mais pesquisas relacionadas à qualidade dos alimentos e aos derivados lácteos obtidos mediante o emprego de grãos de kefir são indicadas, explorando aspectos sensoriais, físico-químicos e microbiológicos destes alimentos, ampliando sua utilização em dietas. / The growing demand for a healthier and value-added food increases the need for research that aims not only to know food, but also to develop and characterize new products. So it is essential that technical professionals working in the food industry and research institutes to work together with health professionals, contributing to the prevention of disease and promotion of health. The overall objective of the study was to develop and evaluate the in loco antibacterial activity of dairy products made from kefir grains against standard foodborne; and to determine the physicochemical and microbiological characteristics of these products. Initially two formulations of kefir fermented milk (kefir 1 and 2) were prepared, the first with pasteurized milk and kefir grains and the second with pasteurized milk, powdered milk and kefir grains. The chemical and mineral composition of raw material (milk and powdered milk) and kefir products was evaluated, and were also determined the pH and the total lactic acid bacteria count. Based on the chemical composition of kefir, there was verified the possible nutritional property statements and also the compliance of the products with the standards of identity and quality for fermented milks. In sequence, two cheese formulations (Q1 and Q2) and serum (S1 and S2) of kefir were prepared from microbial coagulation made with kefir grains and determined the chemical composition and pH. Five different bacterial densities of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 11229) referred as A, B, C, D and E (where A> B> C> D> E) were inoculated in kefir, cheese and whey formulations and determined the in loco antibacterial activity after 0, 24, 48 and 72 hours of confrontation. Five batches of ten commercial brands of pasteurized and UHT milk were evaluated according to the rules for labeling and the identity and quality standards established by the Brazilian food law. The kefir formulations showed significant antibacterial activity against different population densities after 24 hours of exposure and no antibacterial activity was observed between 24 and 72 hours of confrontation. Kefir 1 and 2 met the physicochemical and microbiological parameters established by the technical regulation of identity and quality of fermented milks. Formulation 1 fit the nutrition claims "source of protein", "low calories" and "low sodium", and kefir 2 "high protein content", "low sodium" and "high zinc content". The cheese formulations and kefir whey also showed antibacterial activity against the microorganisms, especially after 24 hours of confrontation. The antibacterial activity was more pronounced against Escherichia coli (ATCC 11229), with highest antibacterial activity after 48 and 72 hour confrontation of different population densities with Q1, Q2, S1 and S2. The kefir whey formulations showed higher antibacterial activity than kefir and cheese. All trademarks evaluated were in accordance with the Brazilian food labeling regulations. One pasteurized milk brand and three whole UHT milk brands did not meet the minimum standards of identity and quality in at least two of the five lots assessed, indicating flaws in the production process. More research related to quality of food and dairy products obtained through the use of kefir grains are indicated by exploring sensory, physicochemical and microbiological aspects of these foods, what could expand its use in diets.
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Efeito de edulcorantes sobre a qualidade de leites fermentados /

Casarotti, Sabrina Neves. January 2009 (has links)
Orientador: Ana Lúcia Barretto Penna / Banca: Susana Marta Isay Saad / Banca: Crispin Humberto Garcia Cruz / Resumo: Os leites fermentados probióticos são líderes no mercado de alimentos funcionais e prioridade de pesquisa em diversos países. A presença de bactérias probióticas viáveis e em alto número no produto durante sua vida de prateleira é condição essencial para assegurar o efeito probiótico. As qualidades tecnológica e funcional de leites fermentados são importantes para sua aceitação pelo consumidor e podem ser afetadas pelos aditivos adicionados antes da fermentação dos produtos. Neste trabalho, o objetivo foi avaliar o efeito da adição de edulcorantes, em diferentes concentrações, na produção de leites fermentados por uma cultura mista composta por Streptococcus thermophilus e Lactobacillus bulgaricus (Rich) e uma cultura pura composta por Lactobacillus acidophilus (La-5). As bases lácteas para preparação dos leites fermentados obtidas antes da fermentação foram submetidas às determinações dos teores de sólidos totais, proteínas, cinzas, gordura, acidez titulável e valor calórico. Nos leites fermentados foram avaliados: a viabilidade das bactérias láticas, a pós-acidificação, a sinérese e a capacidade de retenção de água (CRA), durante 28 dias de estocagem refrigerada. As características físico-químicas dos leites fermentados atenderam aos requisitos legais e apresentaram diferenças somente nos teores de sólidos totais, cinzas e valor calórico nos produtos elaborados com sacarose. O tipo e a concentração de edulcorante afetaram a fermentação da cultura La-5 e a acidez titulável. No entanto, não influenciaram o tempo de fermentação da cultura Rich, a viabilidade de S. thermophilus, L. bulgaricus e L. acidophilus, a sinérese e a CRA dos leites fermentados elaborados. O tipo de cultura influenciou o tempo de fermentação do leite, sendo superiores os tempos obtidos para La-5 e a acidez titulável, com valores superiores para a cultura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fermented probiotic dairy products are leaders in the functional food markets and priority for researching worldwide. The presence of probiotic bacteria viable at high level during shelf-life of the product is essential to ensure the probiotic effect. The technological and functional qualities of fermented milks are important for their acceptance by the consumers and they can be affected by the addition of ingredients before fermentation. The aim of this research was to evaluate the use of sweeteners, in different concentrations, in the production of fermented milks using a mixed culture composed of Streptococcus thermophilus and Lactobacillus bulgaricus (Rich), or a pure culture composed of Lactobacillus acidophilus (La-5). The milk bases obtained before fermentation were submitted to determinations of total solids, protein, ash, fat, acidity contents and caloric value. The viability of lactic bacteria, post-acidification, syneresis and waterholding capacity (WHC) of fermented milks were examined during 28 days of cold storage. The physicochemical characteristics of fermented milks were according to legal requirements and showed differences only on the contents of total solids, ash and caloric value in the products formulated with sucrose. The type and concentration of sweeteners affected the fermentation of La-5 culture and titratable acidity. However they did not influence fermentation time of Rich culture, viability of S. thermophilus, L. bulgaricus and L. acidophilus, syneresis and WHC of fermented milks. The culture type affected the fermentation time, which was higher for La-5 culture, and acidity, which was higher for Rich culture, however, they did not influence the syneresis and WHC of fermented milks. All kinds and concentrations of sweeteners did not influence the technological quality of products, so all of them can be used to produce lowcalorie fermented milks. / Mestre
48

Elaboração e avaliação físico-química e microbiológica de produtos lácteos obtidos a base de kefir

Weschenfelder, Simone January 2016 (has links)
A crescente busca por uma alimentação mais saudável e com valor agregado aumenta a necessidade de desenvolvimento de pesquisas que visem não só conhecer os alimentos, como também desenvolver e caracterizar novos produtos. Assim é fundamental que profissionais da área técnica que atuam em indústrias de alimentos e em institutos de pesquisa, trabalhem em conjunto com os profissionais da área da saúde, contribuindo para a prevenção de doenças e promoção da saúde da população. O objetivo geral do estudo foi elaborar e avaliar a atividade antibacteriana in loco de derivados lácteos elaborados a partir de grãos de kefir frente a microrganismos padrão de interesse em alimentos; e determinar a composição físico-química e microbiológica dos produtos. Inicialmente duas formulações de leite fermentado kefir (kefir 1 e 2) foram elaboradas, a primeira com leite pasteurizado e grãos de kefir e a segunda com leite pasteurizado, leite em pó e grãos de kefir. A composição centesimal e de minerais foi avaliada no leite utilizado como matéria-prima e nas formulações de leite fermentado, onde determinou-se também o pH e foi realizada a contagem de bactérias láticas totais. Com base na composição centesimal do kefir, foi verificada a possibilidade de atribuição de propriedade nutricional ao alimento e a conformidade em relação ao regulamento técnico de identidade e qualidade dos leites fermentados. Na sequencia, duas formulações de queijo (Q1 e Q2) e soro (S1 e S2) de kefir foram elaboradas a partir da coagulação microbiana realizada com grãos de kefir e determinada a composição centesimal e o pH. Cinco diferentes densidades populacionais de Staphylococcus aureus (ATCC 25923) e Escherichia coli (ATCC 11229) referidas no estudo como A, B, C, D e E (sendo A > B > C > D > E) foram inoculadas nas formulações de kefir, queijo e soro, sendo determinada a atividade antibacteriana in loco após 0, 24, 48 e 72 horas de confronto. Paralelamente cinco lotes de dez marcas comerciais de leite pasteurizado e leite UHT foram avaliados quanto à conformidade em relação à legislação de rotulagem e aos padrões de identidade e qualidade estabelecidos pela legislação brasileira. As formulações de kefir apresentaram atividade antibacteriana significativa frente às diferentes densidades populacionais dos patógenos em estudo após de 24 horas de exposição, não sendo observada atividade antibacteriana entre 24 e 72 horas de confronto. Kefir 1 e 2 atenderam aos parâmetros físico-químicos e microbiológicos previstos no regulamento técnico de identidade e qualidade de leites fermentados avaliados no estudo. A formulação 1 pode receber a declaração de “fonte de proteínas”, “reduzido em calorias” e “baixo teor de sódio” e a formulação 2 de “alto conteúdo de proteínas”, “baixo teor de sódio” e “alto conteúdo de zinco”. As formulações de queijo e soro de kefir também apresentaram atividade antibacteriana frente aos microrganismos alimentares testados, principalmente após 24 horas de confronto. A atividade antibacteriana foi mais intensa frente à Escherichia coli (ATCC 11229), obtendo-se atividade antibacteriana máxima após 48 e 72 horas de confronto de Q1, Q2, S1 e S2 com diferentes densidades populacionais do microrganismo testadas. As formulações do soro de kefir foram as que apresentaram maior atividade antibacteriana quando comparadas com o kefir e o queijo. Todas as marcas comerciais de leite avaliadas estavam em conformidade com a legislação brasileira de rotulagem. Uma marca de leite pasteurizado integral e três marcas de leite UHT integral não atenderam aos parâmetros mínimos de identidade e qualidade em pelo menos dois dos cinco lotes avaliados, apontando falhas no processo de beneficiamento. Mais pesquisas relacionadas à qualidade dos alimentos e aos derivados lácteos obtidos mediante o emprego de grãos de kefir são indicadas, explorando aspectos sensoriais, físico-químicos e microbiológicos destes alimentos, ampliando sua utilização em dietas. / The growing demand for a healthier and value-added food increases the need for research that aims not only to know food, but also to develop and characterize new products. So it is essential that technical professionals working in the food industry and research institutes to work together with health professionals, contributing to the prevention of disease and promotion of health. The overall objective of the study was to develop and evaluate the in loco antibacterial activity of dairy products made from kefir grains against standard foodborne; and to determine the physicochemical and microbiological characteristics of these products. Initially two formulations of kefir fermented milk (kefir 1 and 2) were prepared, the first with pasteurized milk and kefir grains and the second with pasteurized milk, powdered milk and kefir grains. The chemical and mineral composition of raw material (milk and powdered milk) and kefir products was evaluated, and were also determined the pH and the total lactic acid bacteria count. Based on the chemical composition of kefir, there was verified the possible nutritional property statements and also the compliance of the products with the standards of identity and quality for fermented milks. In sequence, two cheese formulations (Q1 and Q2) and serum (S1 and S2) of kefir were prepared from microbial coagulation made with kefir grains and determined the chemical composition and pH. Five different bacterial densities of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 11229) referred as A, B, C, D and E (where A> B> C> D> E) were inoculated in kefir, cheese and whey formulations and determined the in loco antibacterial activity after 0, 24, 48 and 72 hours of confrontation. Five batches of ten commercial brands of pasteurized and UHT milk were evaluated according to the rules for labeling and the identity and quality standards established by the Brazilian food law. The kefir formulations showed significant antibacterial activity against different population densities after 24 hours of exposure and no antibacterial activity was observed between 24 and 72 hours of confrontation. Kefir 1 and 2 met the physicochemical and microbiological parameters established by the technical regulation of identity and quality of fermented milks. Formulation 1 fit the nutrition claims "source of protein", "low calories" and "low sodium", and kefir 2 "high protein content", "low sodium" and "high zinc content". The cheese formulations and kefir whey also showed antibacterial activity against the microorganisms, especially after 24 hours of confrontation. The antibacterial activity was more pronounced against Escherichia coli (ATCC 11229), with highest antibacterial activity after 48 and 72 hour confrontation of different population densities with Q1, Q2, S1 and S2. The kefir whey formulations showed higher antibacterial activity than kefir and cheese. All trademarks evaluated were in accordance with the Brazilian food labeling regulations. One pasteurized milk brand and three whole UHT milk brands did not meet the minimum standards of identity and quality in at least two of the five lots assessed, indicating flaws in the production process. More research related to quality of food and dairy products obtained through the use of kefir grains are indicated by exploring sensory, physicochemical and microbiological aspects of these foods, what could expand its use in diets.
49

FOOD SAFETY AND QUALITY IN DEVELOPING COUNTRIES: THE ROLE OF LACTIC ACID BACTERIA

ANGRI, MATTEO 17 March 2016 (has links)
La sicurezza e la qualità degli alimenti sono tutt’ora un problema critico per i paesi in via di sviluppo. Le diete a basso contenuto di acido folico, per esempio, possono causare gravi problemi di salute, soprattutto nei bambini. Gravi disturbi legati al tubo neurale (DTN) nei neonati possono derivare infatti da madri che hanno insufficiente apporto di acido folico (400-600 g / giorno) durante il periodo di gravidanza. Inoltre, se non adeguatamente protetti o trattati, I prodotti alimentari possono essere vettori di funghi e batteri patogeni rappresentando una fonte potenziale di malattie per l’uomo e una perdita economica per le industrie agro-alimentari. Nella seguente tesi si è quindi quindi studiato il ruolo di batteri lattici selezionati (LAB) in grado di aumentare il valore nutrizionale del latte attraverso la produzione di acido folico durante il processo di fermentazione. Inoltre, ci si è concentrati sul loro uso come "bio-conservanti" contro funghi e batteri, attraverso la sintesi di composti antimicrobici (batteriocine) in grado di inibire la crescita di funghi filamentosi e/o batteri patogeni. / The safety and quality of food are still a critical issue in developing countries. Diets with a low content of folic acid, for example, may cause serious health problems, especially in children. Severe disorders related to neural tube (NTD) in infants may arise from mothers having inadequate intakes of folic acid (400-600 g/dia) during the mother pregnancy period. Moreover foods, when not properly protected or treated, can be vectors of pathogenic fungi and bacteria thereby representing a potential source of human diseases and an economical loss for the food industry. In the following thesis we have therefore investigated the role of selected lactic acid bacteria (LAB) in increasing the nutritional value of milk through the production of folic acid during the fermentation process. In addition, we focused on their use as “bio-preservatives” against fungal and bacterial spoilage, through the synthesis of antimicrobial compounds (bacteriocins) able to inhibit the growth of filamentous fungi and /or pathogenic bacteria.
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Biološka aktivnost fermentisanih mlečnih napitaka dobijenih primenom kombuhe i konvencionalnih starter kultura / Biological activity of fermented milk beverages obtained using kombucha and conventional starter culture

Hrnjez Dajana 26 September 2015 (has links)
<p>Proizvodnja fermentisanih mliječnih napitaka unapreijeđenih funkcionalnih karakteristika postala je jedan od glavnih fokusa u industriji prerade mlijeka. Cilj doktorske disertacije je ispitivanje biolo&scaron;ke aktivnosti fermentisanih mliječnih napitaka dobijenih primjenom nekonvencionalne starter kulture, kombuhe (kultivisane na crnom čaju zaslađenim saharozom u koncentraciji od 10%) i poređenje sa karakteristikma proizvoda dobijenih primenom konvencionalnih starter kultura, jogurtne odnosno probiotske, tokom skladi&scaron;tenja. Za fermentaciju je kori&scaron;ćeno mlijeko sa 2,8% mliječne masti na temperatura 42&deg;C.<br />Promjene tokom fermentacije mlijeka primjenom kombuhe i konvencionalnih starter kultura praćene su određivanjem stepena proteolize, sadržaja laktoze, D&ndash; galaktoze, D&ndash;glukoze i D&ndash;fruktoze i masnih kiselina pri sledećim pH vrijednostima: 6,4; 6,0; 5,5; 5,0 i 4,6. Promjene antihipertenzivne aktivnosti (AKE inhibitorna aktivnost), antioksidativne aktivnosti (ABTS i DPPH metod) kao i promjene stepena proteolize, reolo&scaron;kih i senzornih karakteristika sve tri vrste fermentisanih mliječnih napitaka praćene su tokom 21-og dana skladi&scaron;tenja. Osim toga praćene su i promjene sadržaja &scaron;ećera, masnih kiselina, minerala (kalcijuma, natrijuma i kalijuma), vitamina C i biogenih amina.<br />Tokom procesa fermentacije mlijeka primjenom različitih starter kultura može se zaključiti da postoji razlika u promjenama udijela pojedinačnih proteinskih frakcija analiziranih metodom kapilarne elektroforeze.<br />Različite starter kulture utiču na različitu AKE inhibitornu aktivnost tokom skladi&scaron;tenja, &scaron;to ukazuje na različitu proteolitičku aktivnost kori&scaron;ćenih starter kultura. Utvrđeno je da AKE inhibitorna aktivnost raste tokom skladi&scaron;tenja, pri čemu uzorci proizvedeni primjenom kombuhe imaju najveću AKE inhibitornu aktivnost na kraju 14 dana skladi&scaron;tenja i ona iznosi 79,4%, dok su u jogurtu i probiotskom jogurtu te vrijednsoti 63,4 i 64,6% redom. Takođe, tokom skladi&scaron;tenja stepen proteolize raste u svim uzorcima sa značajnim međusobnim varijacijama. Antiksidativna aktivnost svih uzoraka opada tokom skladi&scaron;tenja ali je u svim uzorcima zabilježena veća aktivnost na ABTS nego na DPPH slobodne radikale. Nakon 21-og dana skladi&scaron;tenja najveći antioksidativni potencijal određen metodom stabilizacije ABTS.+ katjona imali su uzorci sa jogurtnom starter kulturom (TEAC vrijednost 8,922 mmolmg-1). U pogledu sastava masnih kiselina, tokom 14 dana skladi&scaron;tenja u kombuha fermentisanim mliječnim napicima<br />kao i napicima dobijenim sa jogurtnom i probiotskom starter kulturom dolazi do porasta udjela zasićenih (SFA) i opadanje mononezasićenih (MUFA) i polinezasićenih masnih kiselina (PUFA). Nakon 21-og dana skladi&scaron;tenja sadržaj SFA; MUFA i PUFA u kombuha fermentisanom mliječnom napitku iznosio je 65,94; 30,73 i 3,33% redom, dok su te vrijednosti kod jogurta iznosile 66,02; 30,77 i 3,21% i probiotskog jogurta 66,04; 30,66 i 3,30 % redom. Najveći sadržaj vitamina C nakon proizvodnje i 14 dana skladi&scaron;tenja imali su uzorci sa kombuha starter kulturom (0,5457 &plusmn; 0,017 mg100g-1). Uzorci dobijeni upotrebom konvencionalnih startera pokazali su bolje reolo&scaron;ke osobine pri ispitivanim uslovima tokom 21 dana skladi&scaron;tenja. Kombuha fermentisani mlečni proizvod imao je karakterističan, blago kiseli, osvežavajući ukus i nagla&scaron;enu aromu.<br />Na osnovu dobijenih rezultata biolo&scaron;ke aktivnosti i promjena kvaliteta kombuha fermentisanog mliječnog napitka tokom skladi&scaron;tenja, u odnosu na karakteristike proizvoda dobijenih upotrebom konvencionalnih starter kultura može se objasniti opravdanost upotrebe kombuha starter kulture u fermentaciji mlijeka sa ciljem dobijanja novog funkcionalnog fermentisanog mliječnog proizvoda.</p> / <p><span style="font-size:11px;">Nowadays, production of fermented dairy products with elevated benefits on human health has become one of the major focuse in dairy industry. The aim of the PhD thesis is to examine the biological activity of fermented milk products obtained using non-conventional starter culture kombucha (cultivated on black tea with 10% of sucrose) and comparision with products obtained by conventional starter cultures, probiotic/yoghurt during storage. Milk with 2.8% of milk fat was used for the samples production at temperature of 42 &deg;C.<br />The changes of components content during the milk fermentation by kombucha and conventional starter cultures were monitored at the following pH values: 6.4; 6.0; 5.5; 5.0 and 4.6., by determining the degree of proteolysis, lactose, D-galactose, D-glucose and D-fructose, fatty acids. The antihypertensive activity (ACE inhibitory activity), antioxidant activity (ABTS and DPPH tests) and the degree of proteolysis, sensory and rheological characteristics of all three types of fermented milk products were observed during 21 days of storage. Moreover, the chemical qualities of samples were monitored analyzing the contents of sugars, fatty acids, minerals (calcium, sodium and potassium), vitamin C and biogenic amines.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; There were differences in protein fractions (analyzed by capillary electrophoresis) of products obtained by using different starter cultures during the milk fermentation. Different starter cultures affect different ACE inhibitory activity during the storage, which implies different proteolytic activity of used starter cultures. It has been found that the ACE inhibitory activity was increased during the storage; wherein the samples obtained using kombucha starter culture have the highest ACE inhibitory activity at the 14th day of storage, 79,4%, while in yogurt and probiotic yoghurt it was 63.4 and 64.6% respectively. Also, the degree of proteolysis during the storage was increased in all samples with significant mutual variations. In all products, higher ABTS than 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was determined, while both activities slightly decreased during the storage. The antioxidant activity of all samples decreases during storage. After 21 days of storage, the highest antioxidant potential, determined by the ABTS. + method had a yoghurt samples (TEAC value of 8.922 mmolmg-1). In terms of the fatty acids composition during 14 days of storage in all type of fermented dairy products relative content of SFA (saturated fatty acids - SFA) increased, while relative contents of MUFA (monounsaturated fatty acids) and PUFA (polyunsaturated fatty acids) decreased during that period of storage. After 21 days of storage the content of SFA; MUFA and PUFA in kombucha fermented milk product was 65.94; 30.73 and 3.33% respectively. In yogurt sample their content was 66.02, 30.77 and 3.21%, while in probiotic 66.04; 30.66 and 3.30% respectively. In all fermented milk products, long chain fatty acids were dominant with a total share of about 45% in all varieties of fermented dairy products. The highest content of vitamin C after production and 14 days of storage was in samples obtained by kombucha starter culture (0.5457 &plusmn; 0.017 mg100g-1). Samples obtained by conventional starter showed better overall rheological properties at the tested conditions for 21 days of storage. Kombucha fermented milk product had a characteristic, distinctive mild sour, refreshing taste and conspicuous aroma.<br />The obtained results of biological activity and the quality of kombucha fermented milk products during storage in comparison to the same characteristics of the products obtained using conventional starter culture, could explain that kombucha is convenient starter for milk fermentation with the aim of obtaining new functional fermented milk products with pronounced bioactive characteristics and distinctive sensory and rheology properties.</span></p>

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