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Cardoso Freitas Lopes de Freitas, Ana Cristina
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- Sweet whey cheese matrices inoculated with the probiotic strain Lactobacillus paracasei LAFTI® L26Publication . Madureira, Ana Raquel; Soares, José Carvalho; Pintado, M. E.; Gomes, Ana M. P.; Freitas, A. C.; Malcata, F. XavierConsumption of dairy products containing viable probiotic strains has increased dramatically in recent years, owing to general health claims associated therewith. This trend has boosted diversification of the portfolio of said products, including whey cheese matrices. However, taking into account the relatively poor organoleptic and textural features of these matrices, improvement is in order via incorporation of selected additives, provided that viability of the strains is duly assayed. Lactobacillus paracasei LAFTI® L26 was accordingly incorporated into whey protein solid matrices, in the presence of several additives aimed at enhancing their organoleptic appeal and textural performance. These matrices were produced from a combination of either ovine or bovine whey (or a mixture thereof) with ovine milk, and were inoculated at 10% (v/v) with the probiotic strain. Sugar, sugar and aloe vera, sugar and chocolate, and sugar and jam were further added, and the resulting products were then stored at 7 ◦C for 21 d. In general, viable cell numbers remained high in all experimental matrices throughout storage. Despite the observed low extents of breakdown, proteolytic activities by the end of storage were higher in matrices containing jam. Furthermore, L. paracasei partially converted lactose into lactic acid in these matrices. Additives enhanced the organoleptic features of whey cheeses, and produced different textural patterns. The higher sensory scores were attained by matrices containing sugar: sugar and aloe vera received the best scores by 3 d of storage, but these scores decreased as storage time elapsed.
- How milk type, coagulant, salting procedure and ripening time affect the profile of free amino acids in Picante da Beira Baixa cheesePublication . Freitas, A. C.; Fresno, J. María; Prieto, Bernardo; Franco, Imaculada; Malcata, F. Xavier; Carballo, JavierThe concentration of total free amino acids (FAA) in Picante cheese increased with ripening time irrespective of the particular protocol used for manufacture (ie ratio of caprine to ovine milks, animal or plant rennet and number of salting steps). The experimental cheeses manufactured with 20% (v/v) caprine milk, coagulated with animal rennet and salted only once exhibited the highest content of total FAA by 120 days of ripening. All four manufacture parameters were statistically significant on the 0.5% level of significance in terms of total concentration of FAA. The dominating free amino acids present in the various experimental cheeses throughout the ripening period were valine, leucine and phenylalanine, each one representing more than 10% (w/w) of the total concentration of FAA. All four manufacture parameters were, in general, statistically significant with respect to the content of every single FAA, with particular emphasis on salting and ripening time.
- Review: Technological and organoleptic issues pertaining to cheeses with denomination of origin manufactured in the Iberian Peninsula from ovine and caprine milksPublication . Freitas, A.C; Macedo, A. C.; Malcata, F. X.A few European countries have created Appélations d'Origine Protegée (AOP) in order to support legal protection and hence promote enforcement of high-quality standards of selected food products. This paper comprehensively reviews and updates fundamental and applied aspects encompassing tech nological and organoleptic characteristics of AOP traditional cheeses manufactured in the Iberian Peninsula, from ovine and/or caprine milks. Those cheeses from Portugal and Spain can be divided into four distinctive groups, based on milk source and rennet type: (i) Azeitão, Castelo Branco, Évora, Nisa, Serpa, Serra da Estrela and La Serena cheeses, manufactured with raw ovine milk and coagulated via plant rennet; (ii) Terrincho, Idiazábal, Manchego, Roncal and Zamorano cheeses, elaborated with raw ovine milk and coagulated via animal rennet; (iii) Cabra Transmontano and Majorero cheeses, manufac tured with raw caprine milk and coagulated via animal rennet; and (iv) Amarelo da Beira Baixa, Picante da Beira Baixa and Rabaçal cheeses, manufactured with mixtures of raw ovine and caprine milks and coagulated via animal rennet. Considerable differences between Portuguese and Spanish AOP cheeses exist; the former are, in general, characterized by softer consistencies and similarities to one another in terms of manufacturing protocols (usually encompassing coagulation of plain raw milk followed by slow draining of the curd), whereas the latter are, in general, larger and firmer.
- Technological optimisation of Picante cheese using microbiological, chemical and physical criteriaPublication . Freitas, A. Cristina; Malcata, F. XavierIn order to optimise the final quality of Picante cheese, several processing parameters (i.e., volumetric fraction of caprine milk, ripening time and percentage of salt added to fresh cheese) were manipulated and gave rise to a number of experimental cheeses produced according to a second-order, composite factorial design. Microbiological, physicochemical, biochemical and textural analyses were carried out in samples from all experimental cheeses. The most important effect in microbiological terms was produced by ripening time, in both linear and quadratic forms; caprine milk fraction and amount of salt added were also found to be significant factors, again in both linear and quadratic forms, especially with respect to total viable mesophilic microorganisms, Enterobacteriaceae and staphylococci. In terms of proteolysis and lipolysis, ripening time was the dominant factor, but caprine milk fraction and NaCl content were also significant at the 5% level. A higher content of caprine milk was associated with higher extents of proteolysis and lipolysis, but the reverse held for NaCl content. It was concluded that 50–80% (v/v) caprine milk, ripening for 195 days and 15% (w/wTS) NaCl provide safe counts of Enterobacteriaceae and staphylococci, while maximising proteolysis and lipolysis in Picante cheese.