Browsing by Author "Franco, M. I."
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- Comparison between sensory descriptors and flavour compounds in an ovine Portuguese traditional cheese (Serra da Estrela)Publication . Franco, M. I.; Machado, P.; Teixeira, S.; Monteiro, M. J.; Tavaria, F.; Ferreira, A. C.; Pintado, M. E.; Malcata, F. Xavier
- Contribution of specific adventitious microorganisms toward evolution of sugar and organic acid orofiles throughout ripening of model portuguese cheesesPublication . Pereira, C. I.; Franco, M. I.; Gomes, E. O.; Gomes, Ana M. P.; Malcata, F. X.Model cheeses, designed to mimic Portuguese traditional cheeses, were manufactured aseptically following a method that attempted to resemble artisanal manufacture practices: they were coagulated with either animal or plant rennet, and inoculated with defined strains of lactic acid bacteria, that had initially been recovered as major constituents of the native microflora of Serra da Estrela cheese, viz. Lactococcus and Lactobacillus genera, either independently or as a mixture. The gross composition, the microbial viability, and the organic compound profile in those model cheeses were monitored, throughout a 60 day-ripening period. Microbial viability, pH, and levels of acetic and lactic acids were the physicochemical and biological parameters that experienced the most significant changes in such matrices – which were, in turn, dependent on the type of inoculum used. No synergisms emerged upon combination of the two strains, in terms of sugar uptake and organic acid release. The contribution of each adventitious bacterium – either independently or in the presence of each other, to the development of expected biochemical characteristics of model cheeses (even though to a lower extent than in actual ones) was confirmed, whereas the type of rennet used proved to be not relevant.
- Evaluation of antimicrobial edible coatings from a whey protein isolate base to improve the shelf life of cheesePublication . Ramos, Ó. L.; Pereira, J. O.; Silva, S. I.; Fernandes, J. C.; Franco, M. I.; Lopes-da-Silva, J. A.; Pintado, M. E.; Malcata, F. X.The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to wrap cheeses, throughout 60 d of storage, as an alternative to commercial nonedible coatings. Coatings were prepared using whey protein isolate, glycerol, guar gum, sunflower oil, and Tween 20 as a base matrix, together with several combinations of antimicrobial compounds—natamycin and lactic acid, natamycin and chitooligosaccharides (COS), and natamycin, lactic acid, and COS. Application of coating on cheese decreased water loss (~10%, wt/wt), hardness, and color change; however, salt and fat contents were not significantly affected. Moreover, the antimicrobial edible coatings did not permit growth of pathogenic or contaminant microorganisms, while allowing regular growth of lactic acid bacteria throughout storage. Commercial nonedible coatings inhibited only yeasts and molds. The antimicrobial edible coating containing natamycin and lactic acid was the best in sensory terms. Because these antimicrobial coatings are manufactured from food-grade materials, they can be consumed as an integral part of cheese, which represents a competitive advantage over nonedible coatings.