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  • Development of a functional goat cheese: exploring bioactive and preservation effects of arthrocnemum macrostachyum
    Publication . Titalah, Sheron Odmia; Ratão, Isabel Maria Carneiro; Custódio, Luísa Margarida Batista
    This work explored the influence of biomass from the halophyte species Arthrocnemum macrostachyum as salt substitute in fresh goat cheese. Biomass was evaluated for mineral contents. The radical scavenging activity towards the 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical, and the total phenolics and flavonoids contents of ethanol extracts of the dried biomass of Arthrocnemum macrostachyum, and cheese, were also evaluated. Fresh and dried biomass from Arthrocnemum macrostachyum were evaluated for microbial quality, as well as functionalized cheese. Cheese was also analyzed in terms of microbiological, physicochemical, bioactive, and functional properties, in different preservation periods. Dried biomass (4g/L) was added to cheese, together with 8 g salt /L (B1) and 4 g salt/L (B2). Cheese with 12 g of salt was used as control (C). Cheese was analyzed at days 0(t0), 4(t4) and 8(t8) of storage at 4C. Ethanol extracts of Arthrocnemum macrostachyum dried biomass were evaluated for antioxidant activity by the DPPH presented half maximal effective concentration of 4 mg/mL. Total phenolic (TPC) and flavonoid (TFC) contents, with values of 23.76 GAE/g DW and 10.35 mg QE/g DW, respectively. The minerals Na, K, Mg, Ca, and Fe were the most abundant. Ethanol extracts were prepared from dried cheeses supplemented with Arthrocnemum macrostachyum, and evaluated for DPPH, TPC and TFC. No antioxidant activity was detected in the cheese extract. Cheese with biomass 8 g salt/L had TPC of 15.17 (t0), 17.12 (t4) and 26.39 (t8) GAE/g DW, cheeses with 4 g salt/L increased from 19.38(t0), 18.90(t4) and 39.94 (t8) mg GAE/g DW. TFC in cheese with 8 g salt increased from 2.80 (t0) to 4.37 (t4) and decreased to 1.88(t8) mg QE/g DW. TFC increased from t4 to t8 in cheese with biomass 4 g salt. B2 was the best cheese in terms of functional and physicochemical properties. Escherichia coli and Staphylococcus coagulase positive were not present in the samples. Microorganisms at 30 °C for fresh and dry samples were 2.37 and 3.50 log CFU/g, respectively. In dry biomass, molds counts were 3.14 log CFU/g, whereas no molds were found in fresh biomass. No yeasts were found in both fresh and dry biomass. There were significant differences between L*, a*, b*, and C* of the cheeses at different storage times. Water activity and fat content were not significantly different (P˃0.05) except for fats in cheese with biomass 4 g salt/L during the first week, pH and dry weight were significantly different (P˂0,05) during the storage. Escherichia coli and Staphylococcus coagulase positive were absent. Salmonella and Listeria monocytogene were not detected in the cheeses. Yeast counts were higher than 5 log CFU/g with no molds.
    2023-04-20Dissertação de mestrado Acesso aberto Ver mais