Texture and sensory changes of a fresh ewe's cheese packed under different modified atmospheres

Shelf-life extension of fresh ewe's milk cheese packaged with three different MAP conditions was studied. Fresh cheeses were stored in barrier trays, hermetically sealed with a barrier to gas and water film. The gas mixtures used were: 20%CO2/80%N2, 30%CO2/70%N2 and 50%CO2/50%N2. Trays were stored at 4°C and inspected at 0,7, 14 and 21 days. Physical-chernical and rnicrobiological analyses (pH, colour, dry matter, aw, mesophilic micro-organisms, psychrotrops, total coliforrns, Escherichia coli, Salmonella, Staphilococcus aureus and Listeria monocytogenes), gas composition inside the packaging (CO2, O2 and N2), texture analysis (puncture test and Texture Pro file Analysis-TPA) and sensory evaluation (acceptability test by scoring for colour, flavour, taste and texture) were carried out. Samples packaged with 30%CO2/70% N2 and 50%CO2/50% N2 had a shelf life of 21 days. Pathogens were not found during all the storage. Cheese stored with 30%CO2/70%N2 reached the best acceptability score to the sensory evaluation

Influenza della temperatura di essiccamento sui polifenoli e sulla capacità antiossidante delle susine Stanley

Changes in phenolic content, antioxidant capacity and ascorbic acid in prunes dried at 85°C and 60°C, were studied. Results obtained showed a significant decrease for ascorbic acid. It has to be highlighted that drying at 85°C resulted in keeping the polyphenolic pool and sharply raising the antioxidant activity, while the opposite happened for plums dried at 60°C. Lo studio ha riguardato l'evoluzione dei composti fenolici e dell'attività antiossidante di susine della varietà Stanley in seguito all’essiccamento a due temperature. Sui frutti freschi ed essiccati sono stati analizzati i composti fenolici, l’acido ascorbico e la capacità antiossidante. I risultati ottenuti hanno evidenziato un decremento significativo dell’acido ascorbico nei campioni essiccati. Si evidenzia che l’uso di un’alta temperatura porta ad un mantenimento della componente polifenolica ed a un aumento di oltre 9 volte dell’attività antiossidante in vitro, rispetto ai frutti freschi, mentre nelle susine essiccate a 60°C si ha una diminuzione di entrambi i parametri

Evoluzione chimico-fisica, sensoriale e della texture di un formaggio fresco pecorino confezionato in atmosfera modificata durante la shelf-life

This paper reports the results obtained from the analysis of a fresh ewe’s cheese packed under different modified atmospheres during the shelf- life. Cheese stored in 80% N2/20% CO2, at the end of the shelf-life was better than cheese packed with a 10% CO2, both for sensory characteristics and for rheological parameters, specially for the puncture force and hardness and chewiness obtained from the TPA assay. The colour was slightly more yellow than the cheese stored with 10% CO2. Il presente lavoro riporta i risultati ottenuti dall’analisi di un formaggio pecorino fresco conservato in atmosfera modificata mediante due differenti condizioni e prodotto ad una settimana di distanza uno dall’altro. L’analisi dei cambiamenti fisico-chimici, di texture e sensoriali durante la shelf-life, ha evidenziato che il campione conservato in atmosfera modificata con una percentuale di N2/CO2 pari a 80/20 si è rivelato qualitativamente superiore rispetto a quello conservato con una percentuale di N2/CO2pari a 90/10, sia per quanto concerne le caratteristiche sensoriali sia per i parametri di texture, in particolar modo per la forza alla rottura in compressione e per la durezza e masticabilità all’analisi TPA, anche se ha mostrato un ingiallimento del colore leggermente superiore rispetto alla prova conservata in miscela di gas 90/10

Effect of drying temperature on polyphenolic content and antioxidant activity of apricots

This study was carried out in order to check for the influence of drying parameters on the phenolic compounds and antioxidant activity on two apricot cultivars (Pelese and Cafona) using two sets of air drying temperatures: (1) air temperature at 55 °C; (2) air temperature at 75 °C. Whole fresh and dried fruits were assessed for: phenolics, ascorbic acid, antioxidant activity and redox potential (all parameters were calculated on a dry matter basis). Analysis of data shows that the decrease in chlorogenic and neochlorogenic acid in Cafona cultivar is higher at the lower drying temperature. Catechin showed the same behaviour of hydroxycinnamic acids in both cultivars, while the decrease in the other compounds was significantly more marked in the sample dried at 75 °C. The antioxidant activity increased significantly in Cafona fruits and this increase was confirmed by a diminution of the redox potential

Effectiveness of active and modified atmosphere packaging on the shelf-life extension of a cheese tart

The shelflife extension by MAP and AP of a typical cheese tart was studied. Baked tarts were packaged inside barrier to gas trays and wrapped with a barrier to gas and water film. Four batches were prepared: 1) Control; 2) MAP with different N2/CO2 ratios (70/30 and 20/80); 3) Trays with an iron oxide-based oxygen absorber. Tarts were stored at 20°C and sampled for analysis at 0,7, 14,27,35 and 48 days. Determinations inc1uded microbioIogical analyses (total bacterial count, moulds, yeast and staphylococci), chemical-physical parameters (pH, water activity and dry matter), gas changes (CO2, O2 and N2) inside MAP and AP trays, texture evolution and sensory analysis at our laboratories. AP allowed a shelf life of 48 days, MAP shelf lives were of 14 and 34 days for 70/30 and (20/80), respectiveIy, while controI tarts spoiled after only 7 days

Contribution of melanoidins to the antioxidant activity of prunes

Prunes, obtained by drying certain cultivars of plums, have greater antioxidant activity than most other fruits and vegetables. Recent research has attributed only a minor part of this antioxidant activity to phenolic compounds, and it has been hypothesized that most of the antioxidant activity is caused by unknown or new products created during processing. In this study, the relationship between the antioxidant properties of prunes and their phenolic compound and brown products content has been investigated. The latter is a result of the nonenzymatic browning reaction. The results show that most of the antioxidant activity of fresh plums is caused by the polyphenolic fraction. The prunes, obtained by drying at 60 and 85C, despite the significant decrease in polyphenols, showed an increase in antioxidant activity. This was mostly because of the nonenzymatic browning reaction products, mostly low molecular weight compounds, whereas polyphenols contributed only to 23% of the total value

Employment of autochthonous microflora in Pecorino Sardo cheese manufacturing and evolution of physicochemical parameters during ripening

The isolation and identification of lactic acid bacteria (LAB) from raw ewes’ milk and traditional Pecorino Sardo cheese made from this milk without the addition of starter culture was carried out to define the autochthonous lactic microflora present in milk and the evolution of LAB during cheese ripening. Isolation of 275 strains belonging to different Lactococcus, Lactobacillus, Streptococcus and Enterococcus species was achieved. Coccal-shaped LAB were found to predominate during cheese fermentation, while lactobacilli were preponderate during the latter phase of ripening. The technological selection of a total of 174 LAB strains belonging to the species Lactococcus lactis, Streptococcus thermophilus, Lactobacillus helveticus and Lb. casei allowed an experimental starter to be prepared, in which a potentially probiotic species, Lb. casei was used. The suitability of the autochthonous starter culture was tested in cheese-making trials, using thermised ewes’ milk, by comparing experimental Pecorino Sardo cheese with a control cheese produced at industrial scale using a whey starter culture from previous batches of manufacture. In particular, microbiological and physicochemical parameters were determined over 210 days of cheese ripening. Although sensory evaluation did not show any significant difference between experimental and control Pecorino Sardo cheeses, the use of the selected autochthonous starter allowed the production of experimental cheese with a significantly higher level of free amino acids, in particular essential amino acids, in comparison with the Pecorino Sardo control cheeses

Prune melanoidins protect against oxidative stress and endothelial cell death

The health-promoting effects of fruit and vegetable consumption are thought to be due to phytochemicals contained in fresh plant material. Whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed plums (prunes) were isolated and their presence confirmed by hydroxymethylfurfural content and browning index. Oxidative-induced endothelial cell (EC) damage is the trigger for the development of cardiovascular diseases (CVD); therefore the potential protective effect of prune melanoidins on hydrogen peroxide-induced oxidative cell damage was investigated on human endothelial ECV304 cells. Cytoplasmic and mitochondrial redox status was assessed by using the novel, redox-sensitive, ratiometric fluorescent protein sensor (roGFP), while mitochondrial membrane potential (MMP) was investigated with the fluorescent dye, JC-1. Treatment of ECV304 cells with hydrogen peroxide dose-dependently induced both mitochondrial and cytoplasmic oxidation, in addition to MMP dissipation, with ensuing cell death. Pretreatment of ECV304 with prune melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide elicited phenomena, clearly indicating that these polymers protect human EC against oxidative stress