Process cheese models were prepared by blending acid or rennet casein, milk fat, sodium chloride, 2.5% emulsifying salt and water and heating to 80 C. Acid casein cheese models were subjected to sodium hydroxide conditioning at 65 C in the cooker. Model process cheeses were acidified with lactic acid and treated by addition of undenatured and heat-denatured whey protein, four different emulsifying salts and sodium oxalate. Meltability and toughness of the model cheese increased to a maximum with increased sodium hydroxide conditioning of acid casein to pH 7.20. These same properties decreased with addition of undenatured and heat-denatured whey protein to both casein cheese models. Loss of emulsion occurred during the meltability test of rennet casein cheese models with 3.0 and 4.5% added whey protein. Emulsifying salts affected the models differently. Disodium phosphate and tetrasodium pyrophosphate in rennet casein models eliminated the melting property. These same salts in acid casein models produced excellent meltability. Trisodium citrate produced cheeses with good meltability in both acid and rennet casein cheese models. Acid casein cheese models prepared with sodium aluminum phosphate had fair meltability and were very tender (no rupture upon compression). Chelation of calcium by sodium oxalate in rennet casein cheese emulsified with disodium phosphate or tetrasodium pyrophosphate improved meltability with a corresponding increase in toughness. Scanning electron micrographs of model process cheeses indicated a direct relationship between extent of emulsification and poor meltability of rennet and pH conditioned acid casein model cheeses. Acid casein model cheeses prepared with different emulsifying salts did not exhibit this same relationship. Addition of whey protein concentrate to rennet case~n model cheese produced fibrous structures around the fat globules. No structural abnormalities were noted in the acid casein cheeses prepared with whey protein concentrate.

This research investigates the protein interactions that occur when soy protein is added to milk and subjected to renneting or heating. Milk was fortified with 20% soy protein and enzymic coagulation studied at 35°C at various pH's and CaCl2 levels. The first part deals with the interaction between milk and soy proteins during rennet-induced milk coagulation. The first goal was to determine how soy proteins affected milk coagulation. The effects of native versus heat-denatured soy proteins on rennet coagulation time and curd firmness were compared. lmmunogold labeling along with transmission electron microscopy was used to identify and localfze soy proteins in coagulated milk. Partitioning of ß-conglycinin and glycinin, the two main soy protein fractions, between cheese and whey was determined by electrophoresis. Soy proteins affected milk coagulation to the greatest extent at pH 6.6. Both heat-denatured and native soy proteins increased rennet coagulation time. Only heat-denatured soy proteins affected final curd firmness. Most of ß-conglycinin was lost in whey, whereas glycinin was retained in curd. Soy proteins existed in the curd as aggregates that were less electron dense than casein micelles. At pH 6.6, heat-denatured soy proteins were fibrous and adhered to the surfaces of casein micelle, preventing direct micelle-micelle contact. This would delay aggregation rate and decrease curd firmness by decreasing the number and strength of links between casein micelles. Native soy proteins did not bind to the casein micelles but rather were physically trapped within curd. Their effect of delaying aggregation is thought to be a function of their binding of calcium. Adding CaCl2 or lowering the pH to 6.3 or 6.0 helped restore coagulation properties. The second goal was to determine what heat-induced interaction occurs between milk and soy proteins, specifically between κ-casein and glycinin. Both κ-casein and glycinin are heat labile and form insoluble aggregates when heated. When glycinin and κ-casein were heated together, some acidic polypeptides of glycinin crosslinked with κ-casein via disulfide linkages. However, when disulfide linkage was prevented by adding ß-mercaptoethanol , non-covalent interactions between κ-casein and both acidic and basic polypeptides of glycinin occurred that prevented the heat precipitation of glycinin. This non-covalent interaction between glycinin polypeptides and κ-casein may explain why the heat-treated soy proteins became attached to the surfaces of casein micelles during rennet coagulation of milk.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-05-16T12:43:03Z No. of bitstreams: 1 Jomar Austregesilo Neto.pdf: 1306936 bytes, checksum: 620dffb525bdd1f0db815a893ef67a66 (MD5) / Made available in DSpace on 2016-05-16T12:43:03Z (GMT). No. of bitstreams: 1 Jomar Austregesilo Neto.pdf: 1306936 bytes, checksum: 620dffb525bdd1f0db815a893ef67a66 (MD5) Previous issue date: 2016-02-25 / This work aims to analyze the quality of management practices used by rennet cheese producers of Pernambuco, addressing the legal aspects of its production and marketing and the perspective that addresses the elements related to the needs and desires of the consumer of this product. The cheese curds can be considered as one of the most popular foods in the Northeast, and represents a major challenge both in meaning as a social and cultural representation, as the economic role it plays. The cheese curd is between products derived from milk, which has more simplified process and manufacturing equipment demand and low complexity technology. In this sense, the scenario that presents itself is great diversity in the form and design of the product method and consequently varying levels of quality in the aspects of health, taste, texture and presentation. The justification of this work is grounded both in the realization of the importance of cheese curds for the region, as the understanding of the need to modernize production in order to meet increasingly demanding markets and consumers with higher levels of information and awareness about food quality . The theoretical framework consisted of literature on quality as a concept and management, using works of the main authors of the subject as Deming, Juran, Crosby and Feigenbaum; literature on consumer behavior, especially on the purchase decision process; manuals and guidelines on the rennet cheese production process, and legislation dealing with pesquisa.que theme is both animal products, the specific legislation on the production of cheese curds, especially the State Law No. 13,376 of 20 December 2007. in order to meet the proposed objective, data were collected from interviews with producers of untamed region of Pernambuco, as well as interviews with traders and consumers of the product, the latter in the Metropolitan region of Recife. The sample used consisted of six companies taken as case studies, a total of nine production units that make up the Association for cheese rennet Certification of Agreste of Pernambuco. From the findings it was established the consistency of quality management practices in both the steps leading up to the production, from the suppliers of raw material, as in the steps of transformation of raw materials into the final product, as within the agricultural industry structure. Such consistency was not observed in the quality of management practices from the distribution of the product until its delivery to the consumer. the importance of logistics intermediaries both in distribution and in product quality maintenance as it is transferred to the retail outlets was found, in addition to identifying the opportunity to strengthen the relationship between producer and point of sale to strengthen a link can increase the quality assurance until the product reaches the consumer. consumer perspective in which the cheese curds and seen as a healthy product and not expensive, and the difficulty that this consumer has to differentiate artisan cheese curds non artisanal cheese curds. / Este trabalho tem como objetivo analisar as práticas de gestão da qualidade utilizadas por produtores de queijo coalho de Pernambuco, abordando os aspectos legais para sua produção e comercialização e a perspectiva que trata dos elementos relacionados às necessidades e desejos do consumidor desse produto. O queijo coalho pode ser considerado como um dos mais populares alimentos na região nordeste, e tem importância destacada tanto no que significa enquanto representação social e cultural, quanto no papel econômico que desempenha. O queijo coalho é, entre os produtos derivados de leite, dos que apresenta processo de produção mais simplificado e com demanda de equipamentos e tecnologia de baixa complexidade. Nesse sentido, o cenário que se apresenta é de grande diversificação na forma e método de elaboração desse produto e consequentemente variados níveis de qualidade nos aspectos de sanidade, sabor, consistência e apresentação. A justificativa deste trabalho está embasada tanto na constatação da importância do queijo coalho para a região, quanto no entendimento da necessidade de se modernizar sua produção no sentido de atender mercados cada vez mais exigentes e consumidores com maiores níveis de informação e consciência sobre qualidade dos alimentos. O referencial teórico utilizado foi composto por literatura sobre qualidade como conceito e gestão, com utilização de obras dos principais autores do assunto como Deming, Juran, Crosby e Feigenbaum; literatura sobre o comportamento do consumidor, em especial sobre o processo de decisão de compra; manuais e orientações sobre o processo de produção de queijo coalho, e a legislação que trata do tema da pesquisa.que trata tanto dos produtos de origem animal, quanto a legislação específica sobre a produção do queijo coalho, com destaque para a Lei estadual Nº 13.376, de 20 de dezembro de 2007. No intuito de cumprir o objetivo proposto, foram levantados dados a partir de entrevistas com produtores da região agreste de Pernambuco, além de entrevistas com comerciantes e consumidores do produto, estes últimos na Região Metropolitana do Recife. A amostra considerada consistiu de seis empresas tomadas como estudos de casos, de um total de nove unidades produtoras que compõem a Associação para Certificação do Queijo Coalho do Agreste de Pernambuco. A partir das conclusões foi possível constatar a consistência das práticas de gestão da qualidade tanto nas etapas que antecedem a produção, junto aos fornecedores da matéria prima, quanto nas etapas de transformação dessa matéria prima em produto final, já dentro da estrutura da agroindústria. Tal consistência não foi observada nas práticas de gestão da qualidade a partir da distribuição do produto até sua disponibilização para o consumidor. Constatou-se a importância dos intermediários logísticos tanto na distribuição quanto na manutenção da qualidade do produto enquanto é trasladado até os pontos de venda de varejo, além de identificar a oportunidade de fortalecer a relação entre produtor e ponto de venda no sentido de fortalecer um elo capaz aumentar a garantia de qualidade até que o produto chegue ao consumidor. Perspectiva do consumidor em que o queijo coalho e visto como um produto saudável e que não custa caro, bem como a dificuldade que este consumidor tem em diferenciar o queijo coalho artesanal do queijo coalho não artesanal.

Orientadores : Salvador Massaguer Roig , Carlos Raimundo Ferreira Grosso / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-22T17:21:26Z (GMT). No. of bitstreams: 1 Dornellas_JoseRaimundoFerreira_M.pdf: 9840953 bytes, checksum: dc81a98e72ffc4f8215d12d6c0b32120 (MD5) Previous issue date: 1997 / Resumo: Avaliou-se neste estudo o emprego de três agentes coagulantes ( bovino, microbiano e obtido por fermentação de E. colí K12, modificada geneticamente) na fabricação do queijo Minas Frescal. Objetivou-se avaliar o "shelf life" do queijo Minas Frescal com o uso dos agentes coagulantes conjuntamente com o uso de fermento lático e ácido lático 85%. Cinco tratamentos repetidos em três dias diferentes, utilizando-se 50 litros de leite para cada tratamento, foram denominados da seguinte forma: BOF (coalho bovino e fermento lático); MICA (coagulante microbiano e ácido lático); MICROF (coagulante microbiano e fermento lático); CHA (coalho obtido por fermentação e ácido lático); CHF (coalho obtido por fermentação e fermento lático). Avaliação do rendimento, proteólise, textura instrumental, cor, microbiologia e sensorial foi efetuada semanalmente, durante o período de um mês, para cada repetição. Não foram detectadas diferenças significativas para as porcentagens de transição de proteína, gordura e extrato seco total. Não foram observadas diferenças significativas no rendimento dos tratamentos, muito embora o rendimento em quilos de leite por quilos de queijo tenha sido maior para o coalho obtido por fermentação, o que sugere uma maior retenção de água no produto final. Os teores de Nitrogênio Solúvel a pH 4,6 e de nitrogênio Solúvel em TCA 12% (NNP), aumentaram significativamente durante o período de "shelf life"do produto ( p=0,0001). Os dados sugerem que a variação do teor de sal no queijo Minas Frescal influenciam os indices de maturação , o que pode ser justificado pela diferença de umidade encontrada entre as repetições. A análise eletroforética dos queijos mostrou maior degradação dos produtos fabricados com coagulante microbiano e fermento lático (MICROF), seguido por coagulante microbiano com ácido lático (MICA), coalho bovino com fermento lático (BOF), coalho obtido por fermentação com fermento lático (CHF) e finalmente por coalho obtido por fermentação com ácido lático (CHA). A degradação da a. 81 ­caseína ocorreu em todos os tratamentos, porém com menos intensidade em CHA. A as1-caseína também apresentou proteólise , com decréscimo perceptível durante o experimento, menos para CHA, onde a ß-caseina praticamente manteve-se intacta. Parece haver um efeito sinergístico acentuado entre o coagulante microbiano e o fermento lático, com o primeiro fornecendo substratos de fácil acesso às enzimas do fermento lático. O queijo processado com o coagulante mais utilizado no país (BOF), mostrou um padrão eletroforético onde a as1-caseína foi nitidamente proteolisada com o tempo. A ß-caseina também foi proteolisada , com decréscimo perceptível durante o experimento. O coalho obtido por fermentação com fermento (CHF), apresentou desdobramento quase que total da a as1-caseína. Estes resultados estão em concordância com os valores de NS a pH 4,6 e TCA 12%. MICROF, BOF, CHF, perderam sua forma física nos primeiros 15 dias de estocagem. A avaliação de textura instrumental para este queijo fica invalidada, devido a heterogeneidade do produto, provocando alta variabilidade entre repetições de um mesmo tratamento. Com relação ao sabor, os tratamentos utilizando coagulante microbiano, foram os únicos que não apresentaram diferença significativa durante o experimento. O ácido lático mostrou ser uma boa alternativa para aumentar o "shelf life" do produto, quanto aparência e forma física, porém o queijo ficou mais exposto ao ataque de microorganismos contaminantes / Abstract: Three coagulating agents (bovine, microbial and one obtained by fermentation using a genetically modified E. col; K12) were evalueted for their use in the processing of Minas cheese. The objetive was to evaluate the shelf life of the cheeses using these coagulating agents together with mesophilic starter and 85%lactic acid. Cheeses were processed on three separate days using approximately 50kg milk for each batch and were denominated as follows: BOF (bovine coagulant plus mesophilic starter); MICA (microbial coagulant plus lactic acid); MICROF (microbial coagulant plus mesophilic starter); CHA (coagulant from fermentation plus lactic acid); CHF (coagulante from fermentation fermentation plus lactic acid). No signifcant differences were found in the percentagen recoveries of the protein, fat and total dry matter. No significant differences were observed in the yields from the treatments although the yield of cheese per kilo of milk was greater using the coagulant obtained by fermentation, suggesting a greater water retention in the final product. The levels of nitrogen soluble at pH 4.6 and in 12% TCA (NNP), increased significanly during the shelf life of the products (p=0,0001). The data suggest that the differences in salt content of the cheeses influenced the indices of proteolysis, which could be justified by the difference in the moisture content found between replicates. WIth respect to the electophoretic behaviour, the greatest protein degradation was shown by the microbial coagulant plus mesophilic starter (MICROF), followed by the microbial coagulant plus lactic acid (MICA), bovine coagulant plus mesophilic starter (BOF), coagulant obtained by fermentation plus mesophilic starter (CHF) and finally the coagulant obtained by fermentation plus lactic acid (CHA). Degradation of as1-casein occurred with all the treatments but was less intense in CHA. The ß casein also showed proteolysis with a perceptible decrease during the experiment, except for CHA, in which the ß-casein remained practically intact. There was apparently an accentuated synergistic effect between the microbial coagulant and the mesophilic starter , with the former providing substrates easily attacked by the enzymes of the latter. The cheese processed by the most commonly used combination in Brazil (BOF), showed an electrophoretic pattern in which the as1- casein was clearly proteoysed with time. The ß - casein was also proteolysed, showing a perceptible decrease during the experiment. The coagulant obtained by fermentation plus mesophilic starter (CHF) resulted in almost complete degradation of the as1-casein. These results are in accordance with the values for nitrogen soluble at pH 4.6 and 12% TCA. MICROF, BOF, and CHF lost their physical form during the first 15 days of storage. The instrumental evaluation of the texture of these eheeses was invalidated on aeeount of the heterogeneity of the products. The sensory evaluation determined the significant differences between the treatments with respect to time. The use of lactie aeid was shown to be a good alternative to inerease the shelf life of the products with respect to appearance and physical form, although it was the most liable to attack by contaminating mieroorganisms / Mestrado / Mestre em Tecnologia de Alimentos

A substrate was developed for measuring the milk clotting strength of rennet preparations on an automatic clot-timer . The substrate contained 8 percent pasteurized skim milk solids, 1 percent chloroform, 0.3 percent 200 bloom gelatin, 0.03 M added CaCl2 and was buffered to pH 6.6 with 0.057 M cacodylic acid and 0.042 M triethanolamine. The substrate was shelf-stable for 18 days at room temperatures. It was found that rennet preparations could be standardized to within 1 percent of each other, in terms of milk clotting strength, by use of the substrate on the automatic clot-timer. The method appears to have advantages over conventional rennet standardizing procedures. The research included studies on the effect of chloroform, nonfat dry milk and CaCl2 concentrations; heat and ionizing radiation on the substrate coagulation time.

The aim of this study was to investigate the impact of the casein microstructure on the molecular diffusion of probes with different sizes and deformabilities. The mobility of molecular flexible ('PEG') and rigid (dendrimer) probes of various sizes was studied in suspensions and gels of NPC and SC at various protein concentrations. Measurements were carried out by NMR, which makes it possible to probe translational mobilities over a distance of 1.5 microns, as well as local mobilities at the molecular scale (several nanometers) through the relaxation times, T2. A coherent model was used and the same mechanism was proposed to describe the diffusion of small probes in both casein dispersions. It is the combination of different factors that should be considered: the ratio of the probe size to the distance between the obstructing particles or the entanglement points, as well as the flexibility of the probe. The rotational diffusion of PEG and dendrimer probes was less hindered than translational diffusion in both casein systems. Different relaxation behaviors were observed between the two casein systems and retardation in T2 relaxation times was highlighted in rennet and acid casein gels. These results are probably related to the local mobility of the matrix. The overall results of this project led to a better understanding of probe mobility in casein systems and made it possible to propose a new model that challenges the previous one proposed by Le Feunteun et al. to describe the diffusion of probes in casein systems.

Die Dicklegung der Milch, ausgehend von der hydrolytischen Spaltung des κ-Caseins, stellt den ersten essentiellen Schritt in der Käseherstellung dar. Dabei finden Gerinnungsenzyme verschiedener Herkunft Anwendung, deren neueste Varianten auf Grundlage des aktuellen Forschungsstandes umfassend charakterisiert werden. Verschiedene Kälberlabpräparate, mikrobielle Gerinnungsenzyme aus Rhizomucor miehei und mit Hilfe von gentechnisch modifizierten Mikroorganismen gewonnenes Chymosin (FPC) aus Rind und Kamel werden mittels HPLC und Elektrophorese hinsichtlich ihrer Zusammensetzung analysiert. Die neueste Generation mikrobieller Enzyme weist im Gegensatz zur herkömmlichen Variante keine Nebenkomponenten und damit einen höheren Aufreinigungsgrad auf. Die unspezifische proteolytische Aktivität wird durch fluorimetrische Quantifizierung der in 12 % TCA löslichen Stickstoffkomponenten bestimmt, die nach Inkubation rekonstituierter Magermilch bei 32 °C und pH 6,5 über 24 h mit den Enzymen freigesetzt werden. Mikrobielle Gerinnungsenzyme besitzen eine signifikant höhere unspezifische proteolytische Aktivität gegenüber chymosinbasierten Präparaten, deren Auswirkung sich bei Erhöhung der zugegebenen Enzymmenge besonders ausgeprägt darstellen. Oszillationsrheometrische Analysen lassen bei gleicher Enzymaktivität eine geringere Gelfestigkeit nach 40 min bei Einsatz von mikrobiellen Präparaten im Vergleich zu Kälberlab und bovinem FPC erkennen. Zusätzlich wird eine Abhängigkeit der Flockungszeit und der Gelfestigkeit vom eingesetzten Substrat beobachtet, die für Chymosin aus Kamel besonders stark ausgeprägt ist. Die Substratspezifität dieses Enzyms ist weder mit der des bovinen Chymosins noch mit der der mikrobiellen Gerinnungsenzyme identisch. Im Rahmen von Käsungsversuchen im Labor-, Pilot- und Industriemaßstab wird eine signifikant höhere Käseausbeute (0,50 - 1,19 %) bei Verwendung vom traditionellem Kälberlab im Vergleich zur neuesten Generation der kommerziellen mikrobiellen Substitute ermittelt. Im Verlaufe der Reifung von Schnittkäse wird durch mikrobielles Gerinnungsenzym gegenüber Kälberlab eine signifikant höhere Menge an Nichtproteinstickstoff freigesetzt sowie ein unterschiedliches Profil an Proteinabbauprodukten gebildet. Die höhere proteolytische Aktivität resultiert in einer signifikant stärker ausgeprägten Bitterkeit der mit mikrobiellem Gerinnungsenzym hergestellten Käse nach 12 Wochen Reifungszeit. / Clotting of milk caused by hydrolytic cleavage of κ-casein is the first important step in cheese milk processing. This cleavage is caused by clotting enzymes of different origin, which are comprehensively characterized by considering results of latest investigations. The composition of selected calf rennets, microbial coagulants derived from Rhizomucor miehei and genetically engineered chymosin (FPC) derived from cow and camel is analyzed by HPLC and electrophoresis. In contrast to conventional products, the latest generation of microbial coagulants does not show minor components in a detectable amount because of a sufficient purification. The unspecific proteolytic activity is determined by fluorimetric quantification of 12 % tricloric-acid-soluble nitrogen, which is released by the enzymes from reconstituted skim milk, pH 6.5, after incubation at 32 °C for 24 h. Microbial coagulants show a significantly higher unspecific proteolysis as compared to chymosin-based clotting enzymes, especially when the enzymes are added in amount higher than used during cheese-making. Small amplitude oscillation rheometry analysis showed a lower gel firmness after 40 min of gelling when microbial coagulants were applied instead of calf rennet or FPC. Furthermore, flocculation time, gel formation time and gel firmness additionally depends on the test substrate, and this dependency is exceptionally pronounced when camel chymosin was used. The substrate specificity of this enzyme is neither identical to that of bovine chymosin nor to that of microbial coagulants. Cheese making experiments in laboratory-, pilot- and commercial-scale revealed a significantly higher cheese yield (0.50 - 1.19 %) when using calf rennet instead of microbial coagulant of the latest generation. During ripening of semi-hard cheese a higher amount of non-protein-nitrogen was released and a different electrophoretic casein degradation profile was generated when using microbial enzymes. Enhanced proteolysis is responsible for a significantly higher pronounced bitterness of microbial produced cheese after 12 weeks of maturation.

The consumer market has incorporated more strongly an old practice of assigning certain products assessments of values that go beyond cost effective. This rating system is based on the certification of quality production, differential of the finished product and the properties that connect their products to an own set of knowledge of a community located geographically. This certification is called the Geographical Indication (GI), which can be in the form of Designation of Origin (DO) or Indication of Origin (IP, in Portuguese). In this sense, this study aimed to analyze the curd cheese type of Nossa Senhora da Glória, Sergipe state, Brazil, considering the conditions of production and the perception of producers in order to check if they meet the basic requirements for obtaining a GI. The question is whether the rennet-curd cheese artisanal shops of the small town studied are prepared to obtain the IG, the National Institute of Industrial Property (INPI, in Portuguese). The research is characterized such as literature, field and case study, based on quantitative and qualitative analysis. It was applied a non-probability sampling for convenience, using the structured questionnaire and interview as tools and applied to the sample of 24 curd cheese type artisanal shops. Quantitative data were treated under the descriptive statistical method. The results showed that the artisanal shops on their part are managed by men (87.5%) and 91% with low education. It also showed that the artisanal shops mostly (95.84%) are not part of any representative body. The owners (95.84%) showed that the cheese know-how has been transmitted from generation to generation. 70% intended production to intermediaries and in foreign markets, mostly in the state of Paraíba. The results show that 100% of artisanal shops are geographically located in the countryside and that these (83.33%) are unaware of the standards and health standards set by the industry. On Good Manufacturing Practices (GMP's), 98% said they do not know and the structure of the little factory does not meet the standards and sanitary standards. All owners have never heard about the IG, but are interested in being part of the recognition and GI registration process. / O mercado de consumo incorporou com mais força uma antiga prática de atribuir a determinados produtos apreciações de valores que vão além da relação custo benefício. Este sistema de valoração é baseado na certificação da qualidade de produção, diferencial do produto acabado e nas propriedades que ligam respectivos produtos a um conjunto de saberes próprios de uma comunidade localizada geograficamente. A esta certificação denomina-se de Indicação Geográfica (IG), que podem ser sob a modalidade de Denominação de Origem (DO) ou Indicação de Procedência (IP). Neste sentido este trabalho objetivou analisar se o queijo de coalho de Nossa Senhora da Glória/SE, considerando as condições de produção e a percepção dos produtores, preenchem os requisitos básicos para uma obtenção de uma IG. A questão é se as fabriquetas de queijo de coalho do município pesquisado estão preparadas para a obtenção da IG, junto ao Instituto Nacional de Propriedade Industrial (INPI). A pesquisa é caracterizada como bibliográfica, de campo e estudo de caso, com base de análise quantitativa e qualitativa. Aplicou-se uma amostragem não probabilística por conveniência, utilizando o questionário estruturado e entrevista como instrumentos e aplicados na amostra de 24 fabriquetas de queijo de coalho. Os dados quantitativos foram tratados sob o método estatístico descritivo. Os resultados evidenciaram que as fabriquetas em sua parte são gerenciadas por homens (87,5%) e 91% com baixo nível de ensino. Evidenciou-se também que as fabriquetas em sua maioria (95,84%) não fazem parte de qualquer entidade representativa. Os proprietários (95,84%) mostraram que o saber-fazer do queijo foi transmitido de geração a geração. 70% destinam sua produção para os intermediários e, no mercado externo, maior parte ao Estado da Paraíba. Os resultados demonstram que 100% das fabriquetas se localizam geograficamente na zona rural e que estas (83,33%) desconhecem as normas e padrões sanitários estabelecidos pelo setor. Sobre as Boas Práticas de Fabricação (BPF’S), 98% responderam que não as conhecem e à estrutura da fabriqueta não atende as normas e padrões sanitários. Todos os proprietários nunca ouviram falar sobre a IG, porém tem interesse de fazer parte do processo de reconhecimento e registro de IG.

Die Dicklegung der Milch, ausgehend von der hydrolytischen Spaltung des κ-Caseins, stellt den ersten essentiellen Schritt in der Käseherstellung dar. Dabei finden Gerinnungsenzyme verschiedener Herkunft Anwendung, deren neueste Varianten auf Grundlage des aktuellen Forschungsstandes umfassend charakterisiert werden. Verschiedene Kälberlabpräparate, mikrobielle Gerinnungsenzyme aus Rhizomucor miehei und mit Hilfe von gentechnisch modifizierten Mikroorganismen gewonnenes Chymosin (FPC) aus Rind und Kamel werden mittels HPLC und Elektrophorese hinsichtlich ihrer Zusammensetzung analysiert. Die neueste Generation mikrobieller Enzyme weist im Gegensatz zur herkömmlichen Variante keine Nebenkomponenten und damit einen höheren Aufreinigungsgrad auf. Die unspezifische proteolytische Aktivität wird durch fluorimetrische Quantifizierung der in 12 % TCA löslichen Stickstoffkomponenten bestimmt, die nach Inkubation rekonstituierter Magermilch bei 32 °C und pH 6,5 über 24 h mit den Enzymen freigesetzt werden. Mikrobielle Gerinnungsenzyme besitzen eine signifikant höhere unspezifische proteolytische Aktivität gegenüber chymosinbasierten Präparaten, deren Auswirkung sich bei Erhöhung der zugegebenen Enzymmenge besonders ausgeprägt darstellen. Oszillationsrheometrische Analysen lassen bei gleicher Enzymaktivität eine geringere Gelfestigkeit nach 40 min bei Einsatz von mikrobiellen Präparaten im Vergleich zu Kälberlab und bovinem FPC erkennen. Zusätzlich wird eine Abhängigkeit der Flockungszeit und der Gelfestigkeit vom eingesetzten Substrat beobachtet, die für Chymosin aus Kamel besonders stark ausgeprägt ist. Die Substratspezifität dieses Enzyms ist weder mit der des bovinen Chymosins noch mit der der mikrobiellen Gerinnungsenzyme identisch. Im Rahmen von Käsungsversuchen im Labor-, Pilot- und Industriemaßstab wird eine signifikant höhere Käseausbeute (0,50 - 1,19 %) bei Verwendung vom traditionellem Kälberlab im Vergleich zur neuesten Generation der kommerziellen mikrobiellen Substitute ermittelt. Im Verlaufe der Reifung von Schnittkäse wird durch mikrobielles Gerinnungsenzym gegenüber Kälberlab eine signifikant höhere Menge an Nichtproteinstickstoff freigesetzt sowie ein unterschiedliches Profil an Proteinabbauprodukten gebildet. Die höhere proteolytische Aktivität resultiert in einer signifikant stärker ausgeprägten Bitterkeit der mit mikrobiellem Gerinnungsenzym hergestellten Käse nach 12 Wochen Reifungszeit. / Clotting of milk caused by hydrolytic cleavage of κ-casein is the first important step in cheese milk processing. This cleavage is caused by clotting enzymes of different origin, which are comprehensively characterized by considering results of latest investigations. The composition of selected calf rennets, microbial coagulants derived from Rhizomucor miehei and genetically engineered chymosin (FPC) derived from cow and camel is analyzed by HPLC and electrophoresis. In contrast to conventional products, the latest generation of microbial coagulants does not show minor components in a detectable amount because of a sufficient purification. The unspecific proteolytic activity is determined by fluorimetric quantification of 12 % tricloric-acid-soluble nitrogen, which is released by the enzymes from reconstituted skim milk, pH 6.5, after incubation at 32 °C for 24 h. Microbial coagulants show a significantly higher unspecific proteolysis as compared to chymosin-based clotting enzymes, especially when the enzymes are added in amount higher than used during cheese-making. Small amplitude oscillation rheometry analysis showed a lower gel firmness after 40 min of gelling when microbial coagulants were applied instead of calf rennet or FPC. Furthermore, flocculation time, gel formation time and gel firmness additionally depends on the test substrate, and this dependency is exceptionally pronounced when camel chymosin was used. The substrate specificity of this enzyme is neither identical to that of bovine chymosin nor to that of microbial coagulants. Cheese making experiments in laboratory-, pilot- and commercial-scale revealed a significantly higher cheese yield (0.50 - 1.19 %) when using calf rennet instead of microbial coagulant of the latest generation. During ripening of semi-hard cheese a higher amount of non-protein-nitrogen was released and a different electrophoretic casein degradation profile was generated when using microbial enzymes. Enhanced proteolysis is responsible for a significantly higher pronounced bitterness of microbial produced cheese after 12 weeks of maturation.

L'objectif de ce travail était d'étudier l'influence qu'exerce la microstructure des caséines sur la diffusion moléculaire de petites sondes ayant des tailles et des déformabilités différentes. La mobilité de sondes moléculaires flexibles (''PEGs'') et rigides (dendrimères) de taille variée a été étudiée dans des suspensions et des gels de PPCN et de CaNa à différentes concentrations en protéines. Les mesures ont été réalisées par RMN qui permet de sonder des mobilités translationnelles sur une distance de 1,5 µm, mais également des mobilités locales à l'échelle moléculaire (quelques nanomètres) à travers les temps de relaxation T2. Un modèle cohérent a été utilisé et un mécanisme unique a été proposé pour décrire la diffusion de petites sondes dans les deux systèmes de caséine. C'est la combinaison de différents facteurs qui doivent être pris en considération : le rapport de la taille de la sonde à la distance entre les particules obstruantes ou les points d'enchevêtrement ainsi que la flexibilité de la sonde. La mobilité locale des sondes était beaucoup moins réduite que la mobilité translationnelle dans les deux systèmes de caséine. Différents comportements de relaxation ont été obtenus entre les deux systèmes de caséine et une diminution des T2 a été mesurée dans les gels. Ces résultats ont été liés à la mobilité intrinsèque de la matrice. L'ensemble des résultats obtenus ont permis d'avoir une meilleure compréhension de la mobilité des sondes dans les systèmes caséiques et de proposer un nouveau modèle qui contredit celui déjà proposé par Le Feunteun et al. pour expliquer la diffusion des sondes dans ces systèmes. / The aim of this study was to investigate the impact of the casein microstructure on the molecular diffusion of probes with different sizes and deformabilities. The mobility of molecular flexible (‘PEG’) and rigid (dendrimer) probes of various sizes was studied in suspensions and gels of NPC and SC at various protein concentrations. Measurements were carried out by NMR, which makes it possible to probe translational mobilities over a distance of 1.5 microns, as well as local mobilities at the molecular scale (several nanometers) through the relaxation times, T2. A coherent model was used and the same mechanism was proposed to describe the diffusion of small probes in both casein dispersions. It is the combination of different factors that should be considered: the ratio of the probe size to the distance between the obstructing particles or the entanglement points, as well as the flexibility of the probe. The rotational diffusion of PEG and dendrimer probes was less hindered than translational diffusion in both casein systems. Different relaxation behaviors were observed between the two casein systems and retardation in T2 relaxation times was highlighted in rennet and acid casein gels. These results are probably related to the local mobility of the matrix. The overall results of this project led to a better understanding of probe mobility in casein systems and made it possible to propose a new model that challenges the previous one proposed by Le Feunteun et al. to describe the diffusion of probes in casein systems.