Alessandra Danza

Shelf life of ready to use peeled shrimps as affected by thymol essential oil and modified atmosphere packaging.

In this work the influence of different packaging strategies on the shelf life of ready to use peeled shrimps was investigated. First, the effectiveness of the coating (Coat) and the active coating loaded with different concentrations of thymol (Coat-500, Coat-1000, and Coat-1500) on the quality loss of the investigated food product packaged in air was addressed; afterwards, the thymol concentration that had shown the best performance was used in combination with MAP (5% O(2); 95% CO(2)). Microbial cell load of main spoilage microorganisms, pH and sensorial quality were monitored during the refrigerated storage. Results of the first step suggested that the sole coating did not affect the microbial growth. A slight antimicrobial effect was obtained when the coating was loaded with thymol and a concentration dependence was also observed. Moreover, the active coating was effective in minimizing the sensory quality loss of the investigated product, it was particularly true at the lowest thymol concentration. In the second step, the thymol concentration (1000 ppm) that showed the strike balance between microbial and sensorial quality was chosen in combination with MAP. As expected, MAP significantly affected the growth of the mesophilic bacteria. In particular, a cell load reduction of about 2 log cycle for the samples under MAP respect to that in air was obtained. Moreover, the MAP packaging inhibited the growth of the Pseudomonas spp. and hydrogen sulphide-producing bacteria. The MAP alone was not able to improve the shelf life of the uncoated samples. In fact, no significant difference between the control samples packaged in air and MAP was observed. Whilst, the use of coating under MAP condition prolonged the shelf life of about 6 days with respect to the same samples packaged in air. Moreover, when the MAP was used in combination with thymol, a further shelf life prolongation with respect to the samples packaged in air was observed. In particular, a shelf life of about 14 days for the active coating under MAP compared to the same samples in air (5 days) was obtained.

A new example of nanotechnology applied to minimally processed fruit: the case of fresh-cut melon.

The effects of silver nanoparticles (Ag-MMT) incorporated into an alginate-based coating applied to fresh-cut melon (Cucumismelo L.) were assessed on the product shelf life. Different concentrations of Ag-MMT nanoparticles were tested in coated melon that was packaged in an oriented polypropylene-based bag and stored at 5°C. Results showed that the active coating was effective from the microbiological and the sensory point of view, if compared to the uncoated fruit that rapidly lost the characteristics responsible for fruit acceptance. A significant shelf life prolongation was recorded from less more than 3 days of the control samples to 11 days of coated fruit, thus promoting further investigation on Ag- MMT coating as valid preservation strategy.

Technological options to control quality of fish burgers

This research was focused on preservation strategies applied to develop fish burgers enriched with tomato flour and extra-virgin olive oil. The effects of three different gas mixtures (5:95 O2/CO2; 10:60:30 O2/CO2/N2 and 5:50:45 O2/CO2/N2) on burger quality were analyzed by monitoring microbial cell load of main spoilage microorganisms, pH and sensory properties. As expected, modified atmosphere packaging significantly affected mesophilic bacteria with a reduction of about 2 log cycles for samples under 5% O2 and 95% CO2. Afterward, the best gas mixture was used in combination with various natural antimicrobial compounds (thymol, grape fruit seed extract and biocitrus). The biocitrus showed the strike balance between microbial and sensory quality, thus suggesting to be adopted for dipping treatment of the entire fish fillet before the mincing process. Later all the strategies tested individually were combined and samples were monitored for microbiological and sensory quality. Results obtained showed that dipping treatment of fillet in biocitrus solution (20,000xa0ppm) under modified conditions extended the shelf life by 8xa0days compared to the control sample, without affecting the sensory acceptability.

Tuna Burgers Preserved by the Selected Lactobacillus paracasei IMPC 4.1 Strain

The use of protective microbial strains in combination with modified atmosphere packaging (MAP) and refrigerated storage on the shelf life of tuna burgers was investigated. Preliminary, the protective ability of three lactic acid bacteria (LAB) cultures (Lactobacillus casei, Lactobacillus paracasei, and Lactobacillus plantarum) have been assessed on ready-to-cook tuna burgers. Among them, L. paracasei showed the best preserving performance and significantly controlled both aerobic mesophilic bacteria and Pseudomonas spp. growth. Subsequently, the efficacy of the selected LAB culture under MAP conditions (5% O2 and 95% CO2) was assessed evaluating microbial and sensory quality, as well as volatile aldehyde content. Results indicated that the shelf life of burgers containing L. paracasei and packaged under MAP was 4xa0days longer than the control (shelf life about 6xa0days) and that the applied procedure represents an effective approach for the mild preservation of fish products.

Senior Consumers Involvement in Developing New Fish-Based Foods Through Sequential Hedonic Tests

Older population needs specific food, adequate to age and health requirements, and acceptable from the sensory point of view. To develop functional products the involvement of senior assessors was experimented. A panel of 35 seniors evaluated fish-burgers and fish-sausages through sensory tests adapted to their cognitive capacities. A model of sequential discrimination, ranking and tetrad tests, was applied with the aim to define the shape (burger vs. sausage), The species and relative percentage of fish, the addition of vegetables, and the presence of potato. The panel indicated a preference for sausage, while ranking tests indicated tuna alone or with mackerel to be preferred. The addition of tomato and artichoke improved acceptance. The acceptance scores showed that progressive discrimination tests successfully supported the development products. This study focusing on age related sensory perception, demonstrated how elderly are able to perform not only simple paired comparisons, but also more demanding ranking tests. There are mainly two practical applications in this work: a methodological one and an applicative one. The methodological is related to the evidence that quite complex and up to date sensory studies, if well structured, can be correctly executed by elder consumers. The applicative output is a preliminary recipe of healthy food for elder people that can be used as milestone in future studies. article History Received: 21 March 2017 Accepted:11 July 2017