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Identification of possible markers for traceability of frozen curd in mozzarella di bufala campana PDO cheese
No full textOn The Possibility to Trace Frozen Curd in Buffalo Mozzarella Cheese
No full textThe manufacturing of Buffalo Mozzarella PDO (Protected Designation of Origin) cheese requires the exclusive use of fresh buffalo milk, which must be transformed into cheese within 60 hours after milking. The limited availability of buffalo milk and simultaneous increase in Mozzarella demand during the summer cause producers to use frozen intermediates (milk and/or curd) in the cheese-making process. These practices are not allowed. Few data are available in the literature about the effects of freezing on buffalo milk and curd. Recent studies demonstrated that the use of frozen buffalo milk can be detected in mozzarella cheese based on the increase in casein fragment γ4-CN. This work aims to verify the possibility of tracing the presence of frozen curd in Buffalo Mozzarella PDO cheese. The electrophoresis technique was used to reveal the presence of γ4-CN. Equivalent concentrations of this fragment were found in fresh and frozen curd that were stored for 9 months. Our results suggest that γ4-CN cannot be used to discriminate fresh PDO Mozzarella and Mozzarella cheese produced from frozen curd. A second objective of the work was to evaluate the effects of freezing on curd lipids. In particular, the fatty acid and mono-diglyceride profiles were evaluated. Significant differences were found in the amounts of 1,2-Dipalmitin and 1,3-Diolein between fresh curd and curd that was stored for 9 months at freezing temperatures. Although some significant differences were found in the mono-diglyceride profiles, no objective marker that can distinguish between fresh and frozen products is currently available
Degradation kinetic (D100) of lycopene during the thermal treatment of concentrated tomato paste
Full text linkHeat treatments can cause degradation in tomatoes of lycopene which has important antioxidant effects. No information about decimal reduction time (D100) of lycopene is available. D-value is the time required at a given temperature to reduce 90% of the molecule. This study for the first time determine the kinetic of lycopene thermal degradation. The content was measured at regular intervals of pasteurization using canned tomato paste to determinate D value. Microbiological analysis was carried out to verify product stability after packaging. Yeasts, molds and lactic acid bacteria were determined. The pasteurization time allowed to observe a loss of the red color. Lycopene content, after an increase at 8 min, decreased at 32 min of pasteurization. D100 value was calculated at 75 min; a diminution of 90% in lycopene content in the concentrated tomato paste was observed. Microbiological analysis confirmed the stability of products after 8 min of pasteurization
Stabilità termo-ossidativa di oli di girasole “alto oleici” nella frittura prolungata e discontinua
No full textStabilità termo-ossidativa di oli di girasole “alto oleici” nella frittura prolungata e discontinua
No full textValutazione della stabilità ossidativa di oli di girasole ad elevato contenuto di acido oleico durante il processo di frittura prolungato e discontinu
A New Method to Distinguish the Milk Adulteration with Neutralizers by Detection of Lactic Acid
Full text linkA liquid chromatographic method based on determining of the amount of lactic acid was developed to detect milk adulteration with neutralizers. The developed method can be applied to milk with pH values within the regular range of 6.5–6.7 that is suspected of being neutralised. Determination of lactic acid was carried out in milk acidified with lactic acid and neutralised with sodium hydroxide to simulate the adulteration. The validation parameters showed high linearity (R2 > 0.99), good precision (relative standard deviation ≤ 0.123%) and high sensibility (limit of detection 0.1 mg/L and limit of quantification 1 mg/L). The proposed method was applied to bacterially acidified and subsequently neutralised milk and detected a content of lactic acid of approximately 40 mg/100 mL in milk slightly acidified to pH 6.4. The developed method is simple, fast, precise and suitable for detecting the addition of hydroxides in sour milk. In parallel, the sodium content was determined in the same sodium hydroxide neutralised samples, but the addition of a small amount of this alkali does not affect the natural variation of sodium in milk
Effects of α-tocopherol and oleic acid content in sunflower oil subjected to discontinuous and prolonged frying process.
Full text linkFrying is a widespread cooking method that positively influences the sensory characteristics of food. Despite the advantages, physical and chemical changes leading to oil degradation can occur. The presence of antioxidants, such as α-tocopherol, and a reduced content of polyunsaturated fatty acids are reported in the scientific literature as factors reducing oxidation processes. The aim of this study was to compare the effects of α-tocopherol addition and the presence of a high concentration of oleic acid in sunflower oil subjected to a prolonged and discontinuous frying process. Every 8 hours of process, the following determinations were performed on oils: free fatty acids (FFA), peroxides value (PV), fatty acids composition (FA), total polar compounds (TPC). High oleic sunflower oil showed the best frying performance, with lower total polar compounds, lower octanoic acid formation and a lower unsaturated/saturated fatty acids (UFA)/(SFA) ratio decrease than oil to which α-tocopherol was added. These results showed that the presence of monounsaturated fatty acids may largely influence the heat resistance of sunflower oil more than the presence of α-tocopherol
Frying Performance of High Oleic Oil Enriched in Biophenols during Discontinuos and Prolonged Thermal Treatment
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