Microbiological, biochemical and biogenic amine profiles of Terrincho cheese manufactured in several dairy farms

Terrincho is a Portuguese traditional cheese, bearing a protected denomination of origin (PDO) status, which is manufactured from raw ewes’ milk and ripened for a minimum period of 30 d. The objectives of this research effort were to characterize the microbiological and biochemical profiles of this cheese, manufactured in several dairy farms during the winter cheesemaking season (December through March), and establish tentative correlations between these profiles and formation of biogenic amines. For this goal, 29 cheeses from five batches, manufactured in as many dairy farms located throughout the PDO region, were analysed. The viable numbers of the total (mesophilic) microflora, enterococci, lactococci, lactobacilli, enterobacteria, staphylococci, pseudomonads, yeasts and moulds were determined by 30 d, following classical plate counting on specific media. Free amino acid and biogenic amine contents were determined by reverse-phase high-pressure liquid chromatography. The concentration of biogenic amines correlated well with microbial viable numbers, in both qualitative and quantitative terms; significant correlations were observed between enterococci and phenylethylamine (r ¼ 0.868, po0.0001), and between lactococci and cadaverine (r = 0.646, p <0.002) and tyramine (r = 0.868, p<0.0001). On the other hand, 220 g of Terrincho cheese would have to be consumed at a given time if the threshold of worst case risk was to be attained, which appears unrealistic for a typically single-doses meal ingredient. This study has contributed to deepen the knowledge on the microbiological and biochemical features of a unique Portuguese cheese throughout ripening, and to rationalize its safe consumption in terms of biogenic amines

Preparation of ingredients containing an ACE-inhibitory peptide by tryptic hydrolysis of whey protein concentrates

This study describes the characterisation of whey protein hydrolysates obtained from tryptic hydrolysis to assess their application as ingredients with angiotensin-converting-enzyme (ACE) inhibitory action. The levels of α-lactalbumin (α-la) and β-lactoglobulin (β-lg) remaining after hydrolysis were quantified. Peptides were separated by RP-HPLC, and Ala-Leu-Pro-Met-His-Ile-Arg (ALPMHIR), the most potent β-lg-derived ACE-inhibitory peptide was monitored. A correlation curve was established for the production of this peptide as a function of hydrolysis time. Heat-induced gelation of hydrolysates was studied by small-deformation rheology. The gelation times and the strength of the final gels were highly dependent on the degree of hydrolysis. Smaller peptides liberated by hydrolysis contributed to the inability of whey protein hydrolysates to gel

Gluino Contribution to the 3-loop QCD beta function in the Minimal Supersymmetric Standard Model

We deduce the gluino contribution to the three-loop QCD \beta function within the minimal supersymmetric Standard Model (MSSM) from its standard QCD expression. The result is a first step in the computation of the full MSSM three-loop \beta function. In addition, in the case of a light gluino it provides the strong three-loop SUSY correction to the extrapolation of the strong coupling constant from the low energy regime to the Z region and up to the squark threshold.Comment: 11 pages, RevTex, 4 Postscript figur

Trypsin hydrolysis of whey protein concentrates: characterization using multivariate data analysis

Hydrolysis of whey protein concentrates (WPCs) was performed using trypsin under different combinations of temperatures and pH values in a total of three experiments, namely experiment A at 37 ºC and pH 8, experiment B at 37 ºC and pH 9, and experiment C at 50 ºC and pH 8. Monitorization of the degradation of native whey proteins and the peptide formation throughout hydrolysis was performed by reverse phase HPLC/UV. Seven main peptides were separated according to their polarity and numbered from T1 to T7. In general a difference was observed between rate of hydrolysis of α-lactalbumin and β-lactoglobulin; in the former case hydrolysis was complete by 15 min in experiments B and C and by 120 min in experiment A, whereas in the later case the rate of hydrolysis was much slower. ANOVA analysis, performed to assess whether the average values obtained for the three experiments conducted to statistically different results for each variable (% of β-lactoglobulin degradation and % of peptides T1 to T7), showed significant differences between experiments A and C. However, between A and B and between B and C no significant differences were observed. Principal Component Analysis evidenced the time period at which similarities and/or differences between experiments were observed. Additionally, a mathematical equation for the degradation of β-lactoglobulin as a function of hydrolysis time was established and some peptides were correlated with their parental protein using linear regression analysis.Fundação para a Ciência e a Tecnologia (FCT

Hidrólise de concentrado proteico de soro de queijo com tripsina imobilizada em resíduos da indústria cervejeira

Neste trabalho utilizou-se um sub-produto da indústria cervejeira proveniente do malte com um teor elevado em celulose, a drêche, como suporte de imobilização para tripsina. Efectuaram-se hidrólises de concentrado proteico de soro de queijo com tripsina imobilizada com diferentes condições de pH e temperatura de forma a determinar os valores óptimos de operação. O perfil dos hidrolisados resultantes foi posteriormente analisado por cromatografia líquida de alta performance em fase reversa. O valor óptimo de operação com tripsina imobilizada ocorreu a 60 ºC, superior à temperatura correspondente com enzima livre. A actividade da enzima imobilizada em drêche foi bastante inferior à da enzima livre. O perfil de péptidos obtido com os dois tipos de enzima foi semelhante.Fundação para a Ciência e a Tecnologia (FCT); Fundo Social Europeu

Parâmetros genéticos de caprinos da raça Saanen nascidos no Brasil de 1979 a 2009.

Resumo: A seleção permite que as características desejáveis sejam transmitidas para seus descendentes e que esses venham a produzir de forma eficiente, porém não existem trabalhos com dados oficiais no Brasil em que houvessem sido estimados os parâmetros genéticos das características biométricas e de tipo em caprinos. Foram avaliadas as características de 1243 caprinos da raça saanen, sendo 197 machos e 1046 fêmeas, nascidos de 1979 a 2009, com os seguintes parâmetros a serem estimados: perímetro torácico, comprimento corporal, altura na cernelha, altura, largura e comprimento da garupa, além das pontuações das principais características que definem o padrão racial e a aptidão do animal em uma escala de 0 a 100 pontos, incluindo a nota final e suas subdivisões, como característica racial, paleta e linha superior, membros e pés, tipo leiteiro, capacidade de corpo, úbere, ligamento traseiro e dianteiro, textura do úbere e tetos. Os componentes de variância foram estimados pelo método da Máxima Verossimilhança Restrita em análises multicaracterísticas incluindo todas as características simultaneamente. Foram encontrados valores de baixos a altos para as estimativas de herdabilidade das características morfofuncionais que variaram de 0,08 a 0,45 e correlações genéticas e fenotípicas de moderadas a altas, evidenciando a existência de variabilidade genética aditiva entre os animais e de possibilidade de resposta correlacionada. Genetic parameters of Saanen goats born in Brazil from 1979 to 2009. Abstract: The selection allows the desirable traits are transmitted to their offspring and that these will produce efficiently, but there are no jobs to official data in Brazil that had been estimated genetic parameters of biometric traits and type in goats. Were evaluated the traits of Saanen goats in 1243, being 197 males and 1046 females born from 1979 to 2009, with the following parameters to be estimated: heart girth, body length, wither height, height, width and length of rump addition to the scores of the main traits that define the breed standard and the suitability of the animal on a scale of 0 to 100 points, including the final score and its subdivisions, such as racial traits, shoulder and topline, limbs and feet, like dairy, capacity body, udder, linking front and rear, texture of the udder and teats. Variance components were estimated by Restricted Maximum Likelihood analyzes multicharacteristics including all features simultaneously. Values were found for low to high heritability estimates of morphological and functional traits that ranged from 0.08 to 0.45 and genetic and phenotypic correlations of moderate to high, showing the existence of additive genetic variability between animals and the possibility of response correlated

Enzymatic hydrolysis of whey protein concentrates : peptide HPLC profiles

Hydrolysis of whey protein concentrates (WPCs) at different temperatures and pHs, using three enzymes: pepsin, trypsin, and Alcalase®, was monitored during more than 5 hr by reversed phase HPLC/UV, using a column containing a polystyrene-divinylbenzene copolymer-based packing, and an elution gradient from 8% to 80% acetonitrile containing 0.1% TFA. Peptides were separated according to their polarity and size, and degradation of α-lactalbumin (α-la) and β-lactoglobulin (β-lg) was evaluated. The three proteolytic enzymes (pepsin, trypsin, and Alcalase®) employed for hydrolysis of WPCs led to different kinetics of degradation of β-lg. α-la degradation after 15 min was almost complete for the three enzymes. The hydrolysis catalysed by each enzyme resulted in different peptide profiles by HPLC/UV. Hydrolysates produced by pepsin (HP) were resolved into three main fractions of high retention times, while tripsin hydrolysates (HT) were resolved into nine major peaks and Alcalase® hydrolysates (HA) were resolved into 12 major peaks, presenting a wide range of polarities and sizes. Although, with different β-lg hydrolysis extension, chromatographic profiles of the degradation and formation of peptides can be used as a finger print of the type of enzyme used, because peptide profile is not affected either by temperature or pH.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/2000/QUI/36452)

Phase Diagram of the Spin-Orbital model on the Square Lattice

We study the phase diagram of the spin-orbital model in both the weak and strong limits of the quartic spin-orbital exchange interaction. This allows us to study quantum phase transitions in the model and to approach from both sides the most interesting intermediate-coupling regime and in particular the SU(4)-symmetric point of the Hamiltonian. It was suggested earlier by Li et al [Phys.Rev.Lett. vol. 81, 3527 (1999)] that at this point the ground state of the system is a plaquette spin-orbital liquid. We argue that the state is more complex. There is plaquette order, but it is anisotropic: bonds in one direction are stronger than those in the perpendicular direction. This order is somewhat similar to that found recently in the frustrated J_1-J_2 Heisenberg spin model.Comment: 8 pages, 4 Postscript figure