Fresh fish is a highly perishable food characterized by a short shelf-life, and for this reason, it must be properly handled and stored to slow down its deterioration and to ensure microbial safety and marketable shelf-life. Modern consumers seek fresh-like, minimally processed foods due to the raising concerns regarding the use of preservatives in foods, as is the case of fresh fish. Given this, emergent preservation techniques are being evaluated as a complement or even replacement of conventional preservation methodologies, to assure food safety and extend shelf-life without compromising food safety. This paper reviews the main mechanisms responsible for fish spoilage and the use of conventional physical methodologies to preserve fresh fish, encompassing the main effects of each methodology on microbiological and chemical quality aspects of this highly perishable food. In this sense, conventional storage procedures (refrigeration and freezing) are counterpointed with more recent cold-based storage methodologies, namely chilling and superchilling. In addition, the use of novel food packaging methodologies (edible films and coatings) is also presented and discussed, along with a new storage methodology, hyperbaric storage, that states storage pressure control to hurdle microbial development and slow down organoleptic decay at subzero, refrigeration, and room temperatures.
Due to its characteristics, fresh fish is a highly perishable food with a very short shelf-life under refrigeration. Several methods have been introduced to slow down its deterioration, such as by means of oxygen depletion of the food package (vacuum packaging), or by changing the natural atmosphere that is in contact with the fresh fish (modified atmosphere packaging), or by the use of chemicals generally recognized as safe: such compounds can be directly applied (by dipping or spraying) or incorporated into packaging materials and slowly migrate to the product, exerting a hurdle effect against microbial development and lipid oxidation (active packaging). This review aims to cover the most recent advances in chemical-based approaches for fresh fish preservation, applied either singly or in combination. Vacuum packaging, modified atmosphere, and active packaging preservation methodologies are presented, along with the inclusion of chemical additives, such as organic acids and natural extracts, and their combination with icing systems. Advantages and disadvantages of these methodologies and their impact on fresh fish quality and shelf-life are discussed, reaching the conclusion that both are positively influenced overall. Indeed, the contribution of chemical-based strategies for fresh fish preservation is undeniable, and is expected to be a research topic of increasing interest in the future.
Pineapple is consumed on a large scale around the world due to its appreciated sensorial characteristics. The industry of minimally processed pineapple produces enormous quantities of by-products (30–50%) which are generally undervalued. The end-of-life of pineapple by-products (PBP) can be replaced by reuse and renewal flows in an integrated process to promote economic growth by reducing consumption of natural resources and diminishing food waste. In our study, pineapple shell (PS) and pineapple core (PC), vacuum-packed separately, were subjected to moderate hydrostatic pressure (225 MPa, 8.5 min) (MHP) as abiotic stress to increase bromelain activity and antioxidant capacity. Pressurized and raw PBP were lyophilized to produce a stable powder. The dehydrated samples were characterized by the following methodologies: chemical and physical characterization, total phenolic compounds (TPC), antioxidant capacity, bromelain activity, microbiology, and mycotoxins. Results demonstrated that PBP are naturally rich in carbohydrates (66–88%), insoluble (16–28%) and soluble (2–4%) fiber, and minerals (4–5%). MHP was demonstrated to be beneficial in improving TPC (2–4%), antioxidant activity (2–6%), and bromelain activity (6–32%) without affecting the nutritional value. Furthermore, microbial and mycotoxical analysis demonstrated that powdered PC is a safe by-product. PS application is possible but requires previous decontamination to reduce the microbiological load.
Opuntia fruits are recognized for their richness in nutrients and in bioactive compounds, being also highly appreciated by consumers as a juice. Nevertheless, without further processing, prickly pear juices have a short shelf-life, hampering their commercial use. In this work, thermal (TP) and high-pressure (HPP) pasteurization were applied to juices from Opuntia ficus-indica cultivars ‘Rossa’, ‘Gialla’, and ‘Bianca’ to understand the impact of those methods on the microbial safety, physico-chemical properties, and the nutritional content of the samples, over storage at 4 °C. In general, thermal pasteurization at 71.1 °C for 30 s increased the shelf-life by 22 days, and high-pressure pasteurization at 500 MPa for 10 min increased the shelf-life by 52 days with regard to microbial growth as well as maintenance of physical-chemical characteristics. The application of these two pasteurization methods delayed changes in the physico-chemical characteristics of the juices, with a more pronounced effect on the titratable acidity, °Brix and browning. For the same periods of time, the application of pasteurization methods decreased the variation in these quality parameters by around 75%. Similarly, these methods were shown to have the same effect on the polyphenolic concentration as well as the antioxidant activity of the juices. In particular, HPP was more efficient in preventing a decrease in °Brix and increase in titratable acidity, which normally negatively affect the flavor of the juices.