Anna Lucia Incoronato

New strategies for reducing the pork back-fat content in typical Italian salami

In this work the possibility to substitute pork backfat with extra virgin olive oil (EVOO), adsorbed on whey protein-based crumb or white bread crumb, in typical Italian salami is addressed. Five types of salami were manufactured, under the usual commercial conditions, by replacing 0 (Control), 60% and 100% of pork backfat with whey protein-based crumb (WP60-WP100) and white pan bread (PB60-PB100), respectively, soaked in EVOO. Results highlighted that pH, weight loss, colour parameters and microbial counts did not show statistically significant differences between the Control and the modified salami. On the other hand, malonaldehyde was slightly lower in PB100, PB60, WP100 and WP60, compared to the Control. Chemical composition was significantly affected by formulations. Modified salami presented a better fatty acid profile showing lower saturated and higher monounsaturated fatty acids than control. Furthermore in all modified salami atherogenic and thrombogenic indices displayed the lowest values. The Control showed the highest values for Warner-Bratzler Shear, hardness, cohesiveness, gumminess and chewiness. Sensory evaluation of WP60 did not show significant differences compared to the Control, whereas PB100 and WP100 were unacceptable for taste.

Active systems based on silver-montmorillonite nanoparticles embedded into bio-based polymer matrices for packaging applications.

Silver-montmorillonite (Ag-MMT) antimicrobial nanoparticles were obtained by allowing silver ions from nitrate solutions to replace the Na(+) of natural montmorillonite and to be reduced by thermal treatment. The Ag-MMT nanoparticles were embedded in agar, zein, and poly(ε-caprolactone) polymer matrices. These nanocomposites were tested in vitro with a three-strain cocktail of Pseudomonas spp. to assess antimicrobial effectiveness. The results indicate that Ag-MMT nanoparticles embedded into agar may have antimicrobial activity against selected spoilage microorganisms. No antimicrobial effects were recorded with active zein and poly(ε-caprolactone). The water content of the polymeric matrix was the key parameter associated with antimicrobial effectiveness of this active system intended for food packaging applications.

Agar hydrogel with silver nanoparticles to prolong the shelf life of Fior di Latte cheese.

The objective of this work was to evaluate the effectiveness of an antimicrobial packaging system containing active nanoparticles on the quality deterioration of Fior di Latte cheese. To this aim, 3 concentrations of silver montmorillonite embedded in agar were used. The cell loads of spoilage and useful microorganisms were monitored during a refrigerated storage period. Moreover, cheese sensory quality (i.e., odor, color, consistency, and overall quality) was evaluated by means of a panel test. Results showed that the active packaging system markedly increased the shelf life of Fior di Latte cheese, due to the ability of silver cations to control microbial proliferation, without affecting the functional dairy microbiota and the sensory characteristics of the product. The active packaging system developed in this work could be used to prolong the shelf life of Fior di Latte and boost its distribution beyond local market borders.

Shelf life of reduced pork back-fat content sausages as affected by antimicrobial compounds and modified atmosphere packaging

The combined use of antimicrobial compounds and modified atmosphere packaging (MAP) on shelf life of reduced pork back-fat content sausages was investigated in this study. First, a pre-screening of different antimicrobial compounds and MAP was addressed. In particular, the consumer test was used as a tool to select the most pleasant antimicrobial compounds, whereas both sausage color and cell load of main spoilage microorganisms were used to choose optimal MAP. Afterwards, antimicrobial compounds (lemon alkott and thymol) and MAP (MAP1: 20% CO(2), 5% O(2), 75% N(2)) that had shown the best performance were used to run the shelf life tests. In order to assess the influence of the variables described beforehand on the shelf life of investigated sausages, the sensorial and microbiological (mesophilic and psychrotrophic bacteria, Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria and coccus-shaped lactic acid bacteria) quality was monitored during storage. Results recorded in this study suggested that Pseudomonas spp. were responsible for sausage unacceptability in all samples, except for thymol and thymol-MAP samples. For these samples, the sensorial quality was the limiting factor while the microbial growth did not limit the shelf life. In particular, for thymol and thymol-MAP samples a shelf life value of more than 5 days with respect to the other samples (2 days) was obtained.

An integrated approach to extend the shelf life of a composite pastry product (cannoli).

In this study, a combined approach is proposed to extend the shelf life of a composite pastry product (cannoli). In particular, to delay moisture migration, one, two, or three layers of a zein-based coating were studied. A three-layer coating represented the most effective solution to prevent rapid pastry softening. A subsequent experimental trial was aimed to prolong the shelf life of the ricotta-based stuffing. To this aim, two different antimicrobial compounds (lysozyme and lemon extract) at three concentrations (2,000, 3,000, and 4,000 ppm) were investigated separately from a microbiological and a sensorial point of view. Lemon extract was the active compound that received a better score, thus suggesting using 2,000 ppm of citrus extract in the last step. In the final experimental trial, cannoli were coated with three layers of zein, stuffed with ricotta containing the selected active agent, and packaged in two microperforated films. The use of zein-based coating and the lemon extract in the ricotta stuffing, combined with the barrier properties of the selected packaging materials, allowed a significant prolongation of cannoli shelf life, regardless of the type of film: a shelf life of more than 3 days was recorded, compared with the control samples, which were acceptable for less than 2 days. It is reasonable to assume that the proposed integrated approach could boost the distribution of the investigated typical pastry beyond local borders.