No abstract

Hyperbaric storage (HS) at variable room temperature (RT) has been proposed as an alternative to refrigeration at atmospheric pressure (RF/AP) for food preservation. Little information is available regarding the effect of HS in meat products. In this study the RT/HS effect was evaluated at 100 MPa and variable RT (≈20 °C) for minced meat preservation up to 24 h, initially for one batch. A further two different batches were studied independently. Microbiological and physicochemical parameters were analyzed to assess the feasibility of RT/HS, using storage at RF/AP and variable RT/AP (≈20 °C), for comparison. A post‐hyperbaric storage (post‐HS) was also tested over 4 days at RF/AP. For the first batch the results showed that RT/HS allowed a decrease of the total aerobic mesophile value (P < 0.05) when compared to the initial sample, whereas at RF/AP and RT/AP, values increased to > 6 Log CFU g−1 after 24 h. Similarly, Enterobacteriaceae increased > 1 and > 2 Log CFU g−1 at RF/AP and RT/AP, respectively, while yeasts and molds presented similar and lower overall loads compared to the initial samples for all storage conditions, whereas RT/HS always allowed lower counts to be obtained. Regarding pH, lipid oxidation, and color parameters, RT/HS did not cause significant changes when compared to RF/AP, except after 24 h, where pH increased. The three batches presented similar results, the differences observed being mainly due to the heterogeneity of the samples. RT/HS is a potential quasi‐energetic costless alternative to RF for at least short‐term preservation of minced meat. © 2018 Society of Chemical Industry

(2015) Preservation under pressure (hyperbaric storage) at 25°C, 30°C and 37°C of a highly perishable dairy food and comparison with refrigeration, CyTA -Journal of Food, 13:3, 321-328, DOI: 10.1080/19476337.2014 To link to this article: https://doi.org/10. 1080/19476337.2014 Hyperbaric storage (HS) under mild pressure of requeijão, a traditional Portuguese whey cheese, as a case study of a highly perishable dairy food, was evaluated as a possible energy costless alternative to refrigeration. Whey cheese was stored for 4 and 8 hours, at different pressure levels (0.1, 100 and 150 MPa) and temperatures (25°C, 30°C and 37°C), and the results were compared with refrigeration (4°C). Microbial analyses showed that storage for 4 hours at 100 MPa was able to maintain microbial counts similar to refrigeration and initial load, ≈3 Log 10 CFU/g, at all tested temperatures. By increasing the pressure to 150 MPa and the storage time to 8 hours, microbial loads were reduced to undetectable counts, with the exception for total aerobic mesophiles that were reduced to about ≈1 Log unit. HS in general maintained pH, water activity and lipid oxidation values, at levels similar to that in refrigeration.Keywords: food preservation; high pressure; hyperbaric storage; refrigeration; whey cheeseEl almacenamiento hiperbárico bajo una presión suave del requeijão, un queso de suero típico en Portugal, como caso de estudio de un producto lácteo altamente perecedero, fue evaluado como una alternativa sin ningún coste energético a la refrigeración. El queso de suero fue almacenado durante 4 y 8 horas, a diferentes niveles de presión (0,1; 100; y 150 MPa) y temperaturas (25, 30, y 37°C). Los resultados fueron comparados con la refrigeración (4°C). Los análisis microbianos mostraron que el almacenamiento de 4 horas a 100 MPa era capaz de mantener los recuentos microbianos similares a los de la refrigeración y carga inicial, ≈3 Log 10 CFU/g, para todas las temperaturas examinadas. Mediante el incremento de la presión a 150 MPa y el tiempo de almacenamiento a 8 horas, la carga microbiana fue reducida a recuentos indetectables, excepto el total de aerobios mesófilos que fue reducido alrededor de ≈1 unidad Log. El almacenamiento hiperbárico en general conservó pH, actividad del agua y valores de oxidación lipídica, a niveles similares a la refrigeración.Palabras clave: conservación alimentos; alta presión; almacenamiento hiperbárico; refrigeración; queso de suero

No abstract

Fourier transform infrared (FT-IR) spectroscopy is a physicochemical technique based on the vibrations of a molecule energized by infrared radiation at a specific wavelength range. Abiotic stresses can induce the production of secondary metabolites, increasing bioactivity. The objectives of the study were to evaluate the impact of heat treatments on the bioactivity of pineapple by-products, and whether FT-IR analysis allows understanding of the changes imparted by abiotic stress. The by-products were treated at 30, 40, and 50 °C for 15 min, followed by storage at 5 ± 1 °C for 8 and 24 h. Lyophilized samples were characterized for total phenolic content and antioxidant capacity and analyzed by FT-IR. Thermal treatments at 50 °C reduced the content of phenolic compounds (21–24%) and antioxidant capacity (20–55%). Longer storage time (24 h) was advantageous for the shell samples, although this effect was not demonstrated for the core samples. The principal components analysis (PCA) model developed with the spectra of the pineapple shell samples showed that the samples were grouped according to their total phenolic compounds content. These results allow the conclusion to be drawn that FT-IR spectroscopy is a promising alternative to the conventional chemical analytical methodologies for phenolic and antioxidant contents if there are significant differences among samples.