Influence of Heat Treatment on the Chemical, Physical, Microbiological and Sensorial Properties of Pork Liver Pâté as Affected by Fat Content.

The novelty of this study is the investigation of the effect of different heat treatments and, simultaneously, the effect of different fat levels on the quality of pork liver pâtés. Hence, this study aimed to evaluate the effect of heat treatment and fat content on selected properties of pork liver pâté. For this purpose, four batches of pâtés with two different fat contents (30 and 40% (w/w)) and two different heat treatments (pasteurisation: target temperature 70 °C, holding time of 10 min; sterilisation: target temperature 122 °C, holding time of 10 min) were manufactured. Chemical (pH, dry matter, crude protein, total lipid, ammonia, and thiobarbituric acid reactive substances (TBARS)), microbiological, colour, textural, rheological, and sensory analyses were performed. Both different heat treatment and fat content affected most of the parameters observed. Sterilisation ensured the commercial sterility of the manufactured pâtés, resulting in elevated TBARS values, hardness, cohesiveness, gumminess and springiness, and increased rheological parameters (G', G″, G*, and η*), as well as colour changes (decrease in L* and increase in a*, b*, and C* values) and deterioration of appearance, consistency, and flavour also being detected (p < 0.05). Higher fat content caused similar variations in the textural and viscoelastic properties, i.e., the increase in hardness, cohesiveness, gumminess and springiness, and also in G', G″, G*, and η* (p < 0.05). However, the colour and sensorial parameters changed in different ways compared to the changes induced by the sterilisation effect. Overall, the observed changes might not be desirable for some consumers and further research would be appropriate to improve especially the sensorial attributes of sterilised pork liver pâtés.

The Impact of Different Hydrocolloids on the Viscoelastic Properties and Microstructure of Processed Cheese Manufactured without Emulsifying Salts in Relation to Storage Time.

The current study was conducted to evaluate the effect of the addition of selected hydrocolloids [agar (AG), κ-carrageenan (KC), or gelatin (PG); as a total replacement for emulsifying salts] on the viscoelastic properties and microstructure of processed cheese (PC) samples during a storage period of 60 days (at 6 ± 2 °C). In general, PC viscoelastic properties and microstructure were affected by the addition of hydrocolloids and the length of storage time. The evaluated PC reported a more elastic behavior (G' > G″) over the viscous one. The highest values of viscoelastic moduli (G'; G″; G*) were recorded for PC samples manufactured with KC addition, followed by those prepared with AG and PG. The control sample presented values of viscoelastic moduli similar to those of the PG sample. All PC samples tested had fat globule size values lower than 1 µm. Moreover, PC with AG and KG addition presented similar microstructures and sizes of fat globules.

Changes in the Quality Attributes of Selected Long-Life Food at Four Different Temperatures over Prolonged Storage.

This study reports the development of selected indicators affecting changes in food quality and safety of selected long-life canned (Szeged goulash, canned chicken meat, pork pâté, canned tuna fish) and dehydrated (instant goulash soup) food during a two-year storage experiment at four different temperatures. The storage temperatures were selected to represent Arctic (−18 °C), temperate (5 °C), subtropical (25 °C) and tropical (40 °C) climatic zones where such food is likely to be stored during, for example, humanitarian and military missions. Microorganism amounts below the detection limit (p < 0.05), regardless of the storage temperature (p ≥ 0.05), were monitored in canned samples. The contents of dry matter, fat and proteins did not change during storage, regardless of the storage temperature (p ≥ 0.05). During the 24-month storage, all food showed an increase in the level of ammonia (p < 0.05) and the TBARS-value (p < 0.05), whereas the rate of increase in both parameters was significantly higher at higher storage temperatures (p < 0.05). The losses of individual amino acids during storage ranged from 5% rel. calculated on the amino acid contents in Month "0" up to 15% rel. (p < 0.05). With storage temperatures above the freezing point, the hardness values decreased with the increase in the storage temperature (p < 0.05) and prolongation of the storage period (p < 0.05). Moreover, with temperatures of −18 °C, the development of hardness, measured as the "decrease rate", was significantly higher compared to the absolute values.