This research explored the potential of the zero-waste concept in relation to the storability of fresh food products. In particular, the prickly pear (Opuntia ficus-indica) peel (usually perceived as a by-product) and the pulp were dehydrated, reduced in powder, and used as food additives to slow down the growth of the main spoilage microorganisms of fresh cod fish burgers. The proportion between peel and pulp powder was such as to respect the zero-waste concept. The antibacterial activity of the peel and pulp in proper proportion was first assessed by means of an in vitro test against target microorganisms. Then, the active powder was added at three concentrations (i.e., 2.5 g, 7.5 g, and 12.5 g) to cod fish burgers to assess its effectiveness in slowing down the microbial and sensory quality decay of burgers stored at 4 °C. The results from the in vitro test showed that both the peel and pulp were effective in delaying microbial growth. The subsequent storability test substantially confirmed the in vitro test results. In fact, a significant reduction in growth rate of the main fish spoilage microorganisms (i.e., Pseudomonas spp., psychrotrophic bacteria, and psychrotolerant and heat-labile aerobic bacteria) was observed during 16 days of refrigerated storage. As expected, the antimicrobial effectiveness of powder increased as its concentration increased. Surprisingly, its addition did not affect the sensory quality of fish. Moreover, it was proven that this active powder can improve the fish sensory quality during the storage period.

The incorporation of 5 and 10% freeze-dried grape pomace powder (GPP) in fresh tagliatelle pasta preparation was evaluated for its effect on chemical composition, gluten protein structure, and sensory properties. The addition of the freeze-dried GPP led to a significant increase (p < 0.05) in polyphenol content in the raw and cooked fortified pasta samples with respect to 100% semolina pasta, although the phenolic content decreased after the cooking process. The opposite phenomenon was observed with the antioxidant activity, which increased significantly (p < 0.05) when switching from raw to cooked pasta samples fortified with GPP. The formation of a proper gluten structure was found in the fortified raw pasta, even if a change in the protein arrangement was shown in the fortified cooked samples, confirmed by a significant reduction (p < 0.05) in both the unextractable polymeric protein percentage (% UPP) and disulfide bond (S-S) formation. These results suggest a possible interaction between the protein sulfhydryl groups (-Cys) and polyphenols of grape pomace during cooking through non-disulfide covalent bonds, which was confirmed by the significant (p < 0.05) decrease in the -SH groups when comparing 100% semolina pasta with fortified pasta sample. Finally, a sensory analysis showed that the highest significant score (p < 0.05) was achieved by the 5% GP-fresh pasta sample.

Protein–protein interactions were investigated, evaluating the influence of eggs and peanut flour on the chemical features of muffin samples. Electrophoretic, immunochemical, and chromatographic analyses were carried out to evaluate how different proteins can interact with one another, determining changes in their extractability. In this context, two extraction buffers were employed to study the rate of protein aggregate formation. Egg coagulation properties were found to affect the rate of wheat protein solubility, while the extractability of roasted peanut flour protein was less influenced and proportional to its amount in the formulation (i.e., 4% and 20%). The findings of this investigation allowed us to assume a complex form of protein organization, characterized by a “core” of wheat and egg proteins surrounded by peanut proteins, linked together through covalent reducible bonds and hydrophobic interactions. Nevertheless, the occurrence of other types of crosslinking could not be excluded.

The surplus in the production of buffalo milk determines the possibility of finding alternative solutions for its use. Indeed, the utilization of milk in cosmetic formulations has been met with great approval by consumers, primarily due to its highly appreciated emollient characteristics. The aim of this research was to test an alternative use of buffalo milk in the production of artisanal solid soaps, using buffalo milk as raw material and Lavender, Thyme, and Grape pomace as sources of natural bioactive compounds. The analytical approach was focused on using vegetable materials in three forms: fresh, dried, and freeze-dried. For this purpose, the chemical features of both raw materials and artisanal soaps were determined in order to understand the feasibility of these productions. All formulated artisanal soaps revealed good chemical characteristics, such as a low moisture content, and got high scores in the sensory evaluation, with those with Lavender and Grape pomace being the most appreciated formulations. Furthermore, adding vegetable materials increased the bioactive molecules content, as demonstrated by the data obtained from total polyphenol content and antioxidant activity. Therefore, the addition of plants and vegetables to the formulation could represent an innovative production of natural soaps and be a further element for the market trends.

Since the problem of food waste has become a global concern, this study has the goal to make full use of the zero-waste concept, aiming to find a way to recycle all the parts of a food product, without producing waste. To the end, prickly pears (Opuntia ficus india) were completely used, without discarding the peel as a by-product (the fruit peel is around 50% of the total product). Pulp and peel were each used to produce an active powder to be added as ingredient in fish burgers. Prickly pears are tropical plants, rich in polyphenolic compounds, and able to control microbial proliferation and general detrimental phenomena occurring in food. For the current study, the pulp and the peel were separately dehydrated and reduced to a fine powder in order to be used as a food ingredient in cod fish burgers to improve sensory quality and prevent microbial growth during storage at 4 °C. An in vitro test of the powders was carried out against target microorganisms. After that, three different amounts (i.e., 2.5 g, 7.5 g and 12.5 g) of peel and pulp in proper combination, were added to the fish burger formulation. Results demonstrate that this addition of the entire prickly pear improved the microbial quality of burgers, reducing the growth of fish spoilage microorganisms (i.e., Pseudomonas spp., psychrotolerant and heat-labile aerobic bacteria and psychrotropic bacteria) and that 12.5 g was the best condition of all those used. In addition, the use of the prickly pears enhanced the sensory properties of the burgers, thus demonstrating that this fruit could be advantageously used, without producing any waste, to prolong food shelf life, with beneficial consequences from the environmental, technological and practical points of view.