Consequences of high-pressure processing of vacuum-packaged frankfurters on the formation of polyamines: Effect of chilled storage

Macroalgae-Fortified Sausages: Nutritional and Quality Aspects Influenced by Non-Thermal High-Pressure Processing

The present work evaluated the nutritional impact of macroalgae flours used as new ingredients in fermented sausages and the feasibility of using high-pressure processing (HPP) as a non-thermal pasteurization methodology to keep the quality attributes of the new food products. A commercial macroalgae mix was used in the formulation of new macroalgae-fortified meat frankfurter sausages (F-MFS), macroalgae-fortified vegetable frankfurter sausages (F-VFS) and in macroalgae-fortified traditional Portuguese sausage "chouriço" (F-TPS), overall incrementing the contents of Mg, K, Ca, Mn and Fe and decreasing the Na/K ratio. The application of HPP allowed extending the shelf-life of frankfurters by about 3-fold and improved the safety of "chouriço" along 180 days of storage, keeping its microbial load below the detection limit. The prevention of microbial growth in F-MFS and F-VFS was accompanied by pH stability of the products. In addition, no significant detriment on surface color and fatty acids was observed between pressurized and non-pressurized sausages, allowing consolidating the suitability of HPP in seaweed-fortified fermented sausages.

Effects of High Pressure Processing and Hot Water Pasteurization of Cooked Sausages on Inactivation of Inoculated Listeria monocytogenes, Natural Populations of Lactic Acid Bacteria, Pseudomonas spp., and Coliforms and Their Recovery during Storage at 4 and 10°C

The study investigated the effects of high pressure processing (HPP; 600 MPa for 3 min) and hot water (HW; 75°C for 15 min) pasteurization on the inactivation of inoculated Listeria monocytogenes, natural populations of lactic acid bacteria, Pseudomonas spp., and coliforms in vacuum-packaged cooked sausages and their recovery during storage at 4 and 10°C for 35 days. Cooking sausages to an internal temperature of 72°C resulted in a >6-log reduction in numbers of inoculated L. monocytogenes. Storage at 4°C resulted in no significant difference ( P > 0.05) in L. monocytogenes numbers in sausages pasteurized by either HPP or HW compared with unpasteurized control. However, at 10°C, L. monocytogenes numbers in unpasteurized control sausages increased to about 7 log CFU/g by day 35, whereas in HPP-pasteurized sausages, numbers remained below the detection limit for up to 21 days and then increased to 4.5 log CFU/g by day 35. HW pasteurization resulted in inhibition of L monocytogenes to below the detection limit throughout the 35-day storage at 10°C. Natural lactic acid bacteria populations were significantly reduced by HPP and HW pasteurization and continued to be significantly lower at the end of the 35-day storage. Unlike most studies that focus on HPP or HW treatment of postcooking surface contamination of meat with Listeria, this study examined the combined effect of cooking, HPP, and HW on raw meat with a high contamination level. This scenario is important in countries where raw meat supply and in-store refrigeration are a challenge. The results suggest that HPP and HW pasteurization could be used to successfully enhance the safety and shelf life of cooked sausages and that HW pasteurization (75°C) was more effective than HPP (600 MPa) to control L. monocytogenes.

Chemical Modifications of Lipids and Proteins by Nonthermal Food Processing Technologies

A range of nonthermal techniques have demonstrated process efficacy in ensuring product safety, extension of shelf life, and in general a retention of key quality attributes. However, various physical, chemical and biochemical effects of nonthermal techniques on macro and micro nutrients are evident, leading to both desirable and undesirable changes in food products. The objective of this review is to outline the effects of nonthermal techniques on food chemistry and the associated degradation mechanisms with the treatment of foods. Oxidation is one of the key mechanisms responsible for undesirable effects induced by nonthermal techniques. Degradation of key macromolecules largely depends on the processing conditions employed. Various extrinsic and intrinsic control parameters of high-pressure processing, pulsed electric field, ultrasound processing, and cold atmospheric plasma on chemistry of processed food are outlined. Proposed mechanisms and associated degradation of macromolecules, i.e., proteins, lipids, and bioactive molecules resulting in food quality changes are also discussed.

Biogenic amines in foods

Biogenic amines are produced by bacterial decarboxylation of corresponding amino acids in foods. Concentration of biogenic amines in fermented food products is affected by several factors in the manufacturing process, including hygienic of raw materials, microbial composition, fermentation condition, and the duration of fermentation. Intake of low amount of biogenic amines normally does not have harmful effect on human health. However, when their amount in food is too high and detoxification ability is inhibited or disturbed, biogenic amines could cause problem. To control concentration of BAs in food, decarboxylase activity for amino acids can be regulated. Levels of BAs can be reduced by several methods such as packaging, additives, hydrostatic pressure, irradiation, pasteurization, smoking, starter culture, oxidizing formed biogenic amine, and temperature. The objective of this review paper was to collect, summarize, and discuss necessary information or useful data based on previous studies in terms of BAs in various foods.

Effect of ultra high pressure homogenization treatment on the bioactive compounds of soya milk

Ultra high pressure homogenization (UHPH) is a useful novel technology to obtain safe and high-quality liquid foods. The effect of UHPH at 200 and 300 MPa in combination with different inlet temperatures (Tin) (55, 65 and 75 °C) on the bioactive compounds of soya milk was studied. Total phytosterols increased with the higher combination of pressure and temperature. The main phytosterol was β-sitosterol, followed by stigmasterol and campesterol. Total tocopherols in UHPH-treated soya milks decreased as the temperature and pressure increased. UHPH treatment also affected the different chemical forms of tocopherols. No biogenic amines were detected in any of the analyzed soya milks. Meanwhile, the polyamines SPD and SPM were found in all soya milks, being stable to the UHPH treatment. Total isoflavones increased with the higher combination of pressure and temperature. No differences in the isoflavone profile were found, with β-glucoside conjugates being the predominant form.