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- Interrelationships among microbiological, physicochemical, and biochemical properties of Terrincho cheese, with emphasis on biogenic aminesPublication . Pinho, Olivia; Pintado, Ana I. E.; Gomes, Ana M. P.; Pintado, M. E.; Malcata, F. Xavier; Ferreira, Isabel M. P. L. V. O.Changes in the microbiological, physicochemical, and biochemical characteristics of Terrincho cheese as represented by native microflora, pH, water activity, soluble nitrogen fractions, free amino acids, and biogenic amines (e.g., ethylamine, dimethylamine, tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, cystamine, and spermine) during ripening were monitored. Terrincho is a traditional Portuguese cheese manufactured from raw ewe's milk. The main groups of microorganisms (lactococci, lactobacilli, enterococci, pseudomonads, staphylococci, coliforms, yeasts, and molds) were determined following conventional microbiological procedures. Free amino acids and biogenic amines were determined by reverse-phase high-performance liquid chromatography, following extraction from the cheese matrix and derivatization with dabsyl chloride. The total content of free amino acids ranged from 1,730 mg/kg of dry matter at the beginning of the ripening stage to 5,180 mg/kg of dry matter by day 60 of ripening; such an increase was highly correlated with the increase of watersoluble nitrogen in total nitrogen, 12% trichloroacetic acid–soluble nitrogen in total nitrogen, and 5% phosphotungstic acid– soluble nitrogen in total nitrogen throughout ripening. Histamine was consistently present at very low levels, whereas putrescine, cadaverine, and tryptamine were the dominant biogenic amines and increased in concentration during ripening. Ethylamine, tryptamine, phenylethylamine, and cystamine reached maxima by 30 days of ripening and decreased thereafter. Significant correlations between amino acid precursors and corresponding biogenic amines, as well as between biogenic amines and microbial viable numbers, were observed.
- Role of dominant microflora of Picante cheese on proteolysis and lipolysisPublication . Freitas, A. Cristina; Pintado, Ana I. E.; Pintado, Manuela; Malcata, F. XavierFour species of bacteria (Enterococcus faecium and E. faecalis, Lactobacillus plantarum and Lb. paracasei) and three species of yeasts (Debaryomyces hansenii, Yarrowia lipolytica and Cryptococcus laurentii) isolated from Picante cheese were assayed for proteolytic and lipolytic activities. The milk type (caprine or ovine), the ripening time (0–65 d) and the concentration of NaCl (0–14% (w/v)) have been studied in terms of their effects upon in vitro curdled milk. Proteolytic and peptidolytic activities were demonstrated to be high for Y. lipolytica, and at much lower levels for the other strains. Milk type, ripening time and content of NaCl appeared to be statistically significant processing factors in terms of proteolysis. Clear lipolytic activity was detected for Y. lipolytica, but release of free fatty acids to lesser extents was observed for the other strains under study. Ripening time was statistically significant for lipolysis but milk type was not. Lipolytic activities were strongly affected by NaCl content and the extent of fat hydrolysis was affected by the increase of NaCl from 0 to 7% (w/v) more than by change from 7 to 14% (w/v). In view of the experimental results, a mixed-strain starter for Picante cheese including Lb. plantarum, E. faecium (or E. faecalis) and D. hansenii (and/or Y. lipolytica) is of potential interest.
- Rheological, textural and microstructural features of probiotic whey cheesesPublication . Madureira, A. Raquel; Pintado, Ana I. E.; Gomes, Ana Maria; Pintado, Manuela E.; Malcata, F. XavierWhey cheeses have been manufactured with probiotic bacteria e viz. Bifidobacterium animalis Bo and Lactobacillus casei LAFTIrL26, from combinations of bovine whey and milk, following protein denaturation at 90 ºC; they were subsequently inoculated (at 10%) with those strains, and homogenized afterwards; additives such as salt and sugar were then incorporated; and the resulting solid matrices were stored at 7º C for up to 21 d. Oscillatory measurements and instrumental texture profile analyses were performed, and sensory analyses were carried out by a trained panel. Microstructural features were in addition ascertained by scanning electron microscopy. L. casei exhibited a higher acidifying activity than B. animalis, which produced distinct textures; higher firmness and viscoelasticity were indeed found in matrices inoculated with the former. Incorporation of sugar and L. casei favoured consumer acceptability, relative to plain matrices. Microstructural differences were detected between matrices at different times of storage and formulated with distinct additives.
- Antioxidant activity of sugar molasses, including protective effect against DNA oxidative damagePublication . Guimarães, Carla M.; Gião, Maria S.; Martinez, Sidónia S.; Pintado, Ana I. E.; Pintado, Manuela E.; Bento, Luís S.; Malcata, F. XavierExtracts were obtained from molasses, a byproduct of the sugar industry, via a number of chromatographic steps. Their antioxidant capacity was studied, including the inhibitory effect upon DNA oxidative damage;the phenolic compound profile there of was ascertained as well. Two extracts exhibited significant antioxidant features, expressed by their capacity to decolorize ABTS radical cation and to scavenge hydroxyl free radicals (via deoxyribose assay). Those 2 extracts also brought about protection against induced DNA oxidative damage (via decreasing DNA scission, as assessed by electrophoresis).The phenolic compounds syringic acid,p-hydroxybenzoic acid, vanillic acid, p-hydroxybenzaldehyde, and ferulic acid were positively identified and quantified.
- Consumer acceptance and sensory profiling of reengineered kitoza productsPublication . Pintado, Ana I. E.; Monteiro, Maria João; Talon, Régine; Leroy, Sabine; Scislowski, Valérie; Fliedel, Geneviève; Rakoto, Danielle; Maraval, Isabelle; Costa, Ana I. A.; Silva, Ana P.; Pallet, Dominique; Tomlins, Keith; Pintado, M. E.Kitoza refers to a traditional way of preparing beef and pork in Madagascar. However, in order to improve some drawbacks previous identified, the product was submitted to a reengineering process. The acceptance and sensory profiling of improved Kitoza products among Portuguese consumers was investigated. A local smoked loin sausage was selected as basis for comparison. Firstly, a Focus Group study was performed to identify sensory descriptors for Kitoza products and explore product perception. Subsequently, a Flash Profile and a consumer sensory acceptance study were conducted. Flash Profile's results showed that beef- and pork-based Kitoza products investigated differed considerably in all sensory dimensions. The Portuguese sausage was characterized as having a more intense and lasting after taste, as well as displaying a higher degree of (meat) doneness. The acceptance study yielded higher overall liking ratings for pork- than for beef-based Kitoza, although the Portuguese sausage remained the most appreciated product.
- Acidifying and aromatic properties of enterococcus strains in ovine and bovine milksPublication . Pimentel, L. L.; Soares, J. C.; Pintado, M. E.; Pintado, Ana I. E.; Gomes, Ana M. P.; Ferreira, A. C.; Malcata, F. X.
- Caseinolytic activity of fruit extract from Opuntia ficus-indica on bovine, caprine, and ovine Sodium CaseinatesPublication . Pintado, Ana I. E.; Macedo, Angela C.; Teixeira, Grimaneza; Pais, Salomé; Clemente, Alda; Malcata, F. XavierThe rates and extents of hydrolysis of RS- and â-caseins from bovine, caprine, and ovine sodium caseinates produced by an enzymatic extract of the fruit of Opuntia ficusindica, (L.) Miller were evaluated and compared with those produced by a commercial animal rennet. A mechanistic model based on a pseudo-first-order enzymatic reaction, in the presence of first-order deactivation of the enzyme, was postulated and successfully fitted to the experimental data. The animal rennet exhibited higher enzymatic efficiency than the fruit extract, irrespective of the source (i.e., bovine, caprine, or ovine) and the type (i.e., RS- or â-casein) of substrate. The enzymatic efficiency (kcat/Km) for RS-casein ranged from 72 to 220 and from 43 to 65 L g-1 h-1, and for â-casein from 242 to 742 and from 55 to 164 L g-1 h-1, for the animal rennet and the enzymatic extract of O. ficus-indica, respectively. Finally, it was observed that â-casein from caprine and ovine caseinates was degraded by O. ficus-indica faster than its RS counterpart, but the reverse was observed for bovine caseinate.
- Consumers’ sensory perception and acceptability of Hibiscus drinks: a cross-cultural study in EuropePublication . Monteiro, M. J.; Costa, A. I. A.; Fliedel, G.; Bechoff, A.; Maraval, I.; Pintado, A. I. E.; Cisse, M.; Pallet, D.; Tomlins, K.; Pintado, M. M.Important differences can be observed between consumers from different countries due to the strong impact of culture on food preferences and acceptance, while a less important effect is usually expected in sensory perception. In the present study consumer’s sensory perception, preference and acceptability of Hibiscus drinks (an African functional drink rich in anthocyanins) were evaluated in three European countries: United Kingdom, France and Portugal. The drinks were developed under the scope of AFTER, an EU FP7-funded research project aiming at the production of improved quality and extended shelf-life products of African tradition for local and European markets. Hibiscus drinks are rich in nutrients and their consumption is widespread in Africa and Asia, but they still are quite unknown amongst European consumers. The sensory quality and acceptability of two Hibiscus drinks developed by AFTER researchers, as well as a traditional infusion prepared from Hibiscus flowers (baseline), were evaluated by 3 independent samples of consumers (France n=143; United Kingdom n=126; Portugal n=124) from March to June 2014. All factors concerning consumers’ socio-demographic profiles and materials were maintained as similar as possible. To gather evaluative relevant information and maximize the equivalence between questionnaires, exploratory local focus groups were held. Consumer profiling techniques based on hedonic acceptance, Just-About-Right intensity evaluation of specific descriptors (JAR) and Check-All-That-Apply questions (CATA) were used to establish sensory profiles and preference maps. Additionally, the chemical composition of the drinks was evaluated and a conjoint analysis was held to determine how consumers valued the composition and African origin of the drinks.Similar preference profiles for the Hibiscus drinks were obtained for the three countries but significant differences were observed in relation between consumers’ acceptance, with French consumers being generally the most appreciative. Importantly, these differences in acceptance were significantly correlated with the drinks sensory profiles and chemical composition.
- Fate of nitrogen during metabolism of whey lactose by Rahnella aquatilisPublication . Pintado, Manuela E.; Pintado, Ana I. E.; Malcata, F. XavierThe rate of intake of peptides and free amino acids by Rahnella aquatilis was studied, as well as the evolution of concentrations of exopolysaccharide, biomass, and several metabolites. For this purpose, eight wheybased fermentation media were tested: hydrolyzed bovine whey under 1) aerobic and 2) anaerobic conditions; hydrolyzed bovine whey with 3) 2.0% (wt/vol) NaCl or 4) 0.5% (wt/vol) NaCl; 5) plain bovine whey; 6) bovine whey permeate; 7) hydrolyzed caprine whey; and 8) hydrolyzed ovine whey. The lower peptide fraction (<2000 Da) in plain whey, whey permeate, and hydrolyzed whey fermented aerobically was virtually depleted by 24 h. In all experiments, most consumption of free amino acids occurred at initial stages of fermentation. In caprine whey, ovine whey, and bovine whey fermented anaerobically, free Val was present at high levels until the end of fermentation, and the highest production of acetic acid was also observed. In ovine whey, high levels of peptides and free amino acids were recorded, as well as the highest production of several organic acids (except lactic acid) and the lowest viscosity and polysaccharide concentration. The low concentration of peptides and free amino acids in plain whey and whey permeate did not apparently permit active consumption of lactose, whereas lack of molecular oxygen and presence of salt played a strong role toward inhibition of exopolysaccharide production. The qualitative and quantitative profile of the nitrogen fraction likely might have determined the metabolism of lactose and, consequently, conditioned the production of exopolysaccharide and organic acids even though growth of R. aquatilis was not affected similarly.
- Efficiency of purification methods on the recovery of exopolysaccharides from fermentation mediaPublication . Pintado, Ana I. E.; Ferreira, José A.; Pintado, Maria M. E.; Gomes, Ana M. P.; Malcata, F. Xavier; Coimbra, Manuel A.De-Man Rogosa and Sharpe (MRS) is a complex medium commonly used to obtain exopolysaccharides (EPS) from lactic acid bacteria. However, the various nutrients (carbon and nitrogen sources) of media and supplements added to enhance the bacterial growth and EPS production, may interfere with the purification of the extracts resulting in an over-estimation of the EPS and erroneous structural assignments. The efficiency of trichloroacetic acid (TCA)/pronase and 5-sulfosalicylic acid – SSA methods was evaluated. In addition, the interference of the major MRS broth components as well as lactose was evaluated using xanthan gum as model control EPS. It was concluded that MRS medium is a major source of interfering compounds in the quantification of EPS, mainly glucose-rich material and to a lesser extent mannoproteins from yeast extract. This effect was found to be potentiated by the presence of lactose. TCA/pronase method was shown to be more efficient in eliminating interferents.