Improving the Storability of Cod Fish-Burgers According to the Zero-Waste Approach

Improving the Shelf-Life of Fish Burgers Made with a Mix of Sea Bass and Sea Bream Meat by Bioprotective Cultures

Seafood products are one of the most perishable foods, and their shelf life is limited by enzymatic and microbial spoilage. Developing methods to extend the shelf life of fresh fish could reduce food waste in the fishery industry, retail stores, and private households. In recent decades, the application of lactic acid bacteria (LAB) as bioprotective cultures has become a promising tool. In this study, we evaluated the use of four starter cultures, previously selected for their properties as bioprotective agents, for sea bass and sea bream burgers biopreservation. Starter cultures impacted the microbial populations, biochemical parameters (pH, TVB-N), and sensory properties of fish burgers, during 10 days of storage at 4 °C and then 20 days at 8 °C in modified atmosphere packaging (MAP). Also, storage time influenced the microbial and physicochemical characteristics of all the tested samples, except for TVB-N values, which were significantly higher in the uninoculated burgers. The volatilome changed in the different treatments, and in particular, the samples supplemented with starter presented a profile that described their rapid growth and colonization, with the production of typical molecules derived from their metabolism. The addition of bioprotective cultures avoided bloating spoilage and improved the sensory parameters of the burgers. The shelf life of the fish burgers supplemented with starter cultures could be extended up to 12 days.

Quality Preservation of Ready-to-Eat Prickly Pears by Peels Recycling

In the current study, prickly pear peel was advantageously recycled to preserve fruit quality. Specifically, the investigated by-products were transformed into powder and then loaded into an alginate-based solution to be applied as coating to peeled prickly pears, to give an example of sustainable minimally processed fruit. For comparison, uncoated fruit, and coated prickly pears without any powder were also prepared. During storage at refrigerated temperature, coated and uncoated samples were tested for weight loss, microbial and fungal proliferation, as well as for sensory quality acceptance. The results were interesting because great differences were found between coated and uncoated fruit, in that coating the fruit delayed weight loss and spoilage, compared to uncoated fruit. Between the simple coating and the coating with peel powder, slight differences were recorded in favor of the peel-enriched coating. In fact, it allowed the promotion of better fruit preservation, and sensory quality. Therefore, prickly pear peels, that represent abundant by-products during prickly pear processing, could be advantageously recycled to preserve fruit quality.

Zero-Waste Approach Applied to Pomegranates for Prolonging Fish Burger Shelf Life

In this study, the possibility of using whole pomegranate (juice, peel and seeds) according to the zero-waste approach, to prolong fresh fish shelf life, was evaluated. A preliminary antimicrobial in vitro test was carried out with peel and seeds as ground and re-ground powders. Then, the entire fruit, in the right proportions of juice and relative by-products as ground or re-ground powders, was added to fresh fish burger formulation to extend its shelf life. To this aim, a shelf-life test was performed on fortified fish products stored at 4 °C. Control samples were also tested for comparison. Specifically, the pH and microbiological and sensory quality of all the fish burgers were monitored during refrigerated storage for about 1 month. The results from the in vitro test clearly indicate that the peel is abundantly more effective than seeds on selected spoilage bacteria and that the ground peel powder is slightly more antimicrobial than the same re-ground powder. Results from the shelf-life test assessed that the control sample became unacceptable within a few days (about 3 days), while the samples with pomegranate juice and by-products maintained microbial stability for a longer time (2 or 3 weeks) (p < 0.05). The main microbiological problems are the proliferations of mesophilic and psychrotrophic bacteria, Pseudomonas spp. and Shewanella. The addition of pomegranate to the formulation allowed the fish spoilage to be controlled by at least 2 or 3 log cycles. In agreement with findings from the in vitro test, the best results from the microbiological point of view were found in fish burgers with juice, peel and seed ground powders. Furthermore, the addition of pomegranate was also appreciated from the sensorial point of view. In fact, products with pomegranate were prized for about 3 weeks for color, odor, appearance and texture of both raw and cooked products. Therefore, the current study reveals that the incorporation of the entire pomegranate, added in all parts according to the zero-waste concept, could promote a significant shelf-life extension of fish burgers, mainly due to the bioactive compounds present in fruit by-products, without changing the sensory quality.