G. Barreto

Binding properties and colour of Bologna sausage made with varying fat levels, protein levels and cooking temperatures

A little-studied procedure for adjusting the properties of low-fat products is to use the influence that both composition and certain processing factors exert on these properties. The object of the present work was to assess the effects of protein level (P, ranging from 10% to 16%), fat level (F, ranging from 10.1% to 22%) and cooking temperature (HT, ranging from 77 °C to 105 °C) on the binding properties and colour of meat emulsions. Protein content was the variable that most influenced total expressible fluid (TEF) and purge loss. Heating rate had scarcely any effect on the binding properties of Bologna sausages. Analysis of variance indicated that the regression models for parameters L, a and b were not significant.

Frozen storage of Bologna sausages as a function of fat content and of levels of added starch and egg white

The effect of freezing and frozen storage on the water holding capacity (WHC) and texture of Bologna sausages formulated with varying fat levels (7.2, 12.8 and 20.1%) and with different proportions of added starch (0, 5 and 10%) and egg white (EW) (0, 1.5 and 3%) was studied. High-fat sausages exhibited better binding properties than low-fat sausages. Freezing and frozen storage caused binding properties to deteriorate, the more so the lower the fat content. In general, addition of starch caused an increase in penetration force and a decrease in elasticity of sausages, and also favoured freeze-thaw stability. Addition of egg white had no influence (p > 0.05) on the WHC of Bologna sausages but did influence texture.

High-pressure-induced changes in the characteristics of low-fat and high-fat sausages

The purpose of this study was to analyse the consequences of applying high pressures (100 and 300 MPa for 5 and 20 min) on characteristics such as water and fat binding properties, texture, colour, microstructure and microbiology of low-fat (90 g kg -1 , LF) and high-fat (247 g kg -1 , HF) meat emulsions. Pressurising of LF and HF samples at 300 MPa caused a decline (P < 0-05) in emulsion stability, which was more pronounced at the higher pressure. The influence of high pressures on emulsion texture varies according to fat content. In HF samples, high pressure caused a decrease (P < 0.05) in Kramer shear force and Kramer energy, regardless of pressure intensity or time. Pressurisation generally caused increase (P < 0.05) in the colour lightness parameter in sausages; the effect on redness and yellowness, however, was dependent on fat content, pressure intensity and pressure time.

Characteristics of High- and Low-Fat Bologna Sausages as Affected by Final Internal Cooking Temperature and Chilling Storage

A study was made of the effect that final internal processing temperature (63, 70 and 78°C) and chilling storage (2°C) exerted on the characteristics (cooking loss, purge loss, colour, Instron texture profile analysis) of high-fat (242 g kg -1 ) and low-fat (100 g kg -1 ) bologna sausage. High-fat sausages were harder and chewier than low-fat sausages. Lower fat contents were accompanied by a significant reduction in the cooking loss and purge loss. Binding properties were not affected (P > 0.05) by final internal cooking temperature. In general, Hunter colour parameter a values were higher in low-fat samples subjected to a high final internal cooking temperature than in those cooked up to only 63°C. High internal temperatures produced harder meat emulsions, an effect which was more pronounced in high-fat than in low-fat sausages. Cohesiveness and springiness of sausages was not affected (P > 0.05) by heat treatment. There were no major variations in textural parameters as a result of chilled storage.

Chopping temperature effects on the characteristics and chilled storage of low- and high-fat pork Bologna sausages

The object of this study was to investigate the influence of chilled storage (2 °C) and final chopping temperatures (8, 15 and 22 °C) on the characteristics and stability of Bologna sausage containing two levels of fat (8.5 and 23%). When the fat level was reduced there was a significant decrease in penetration force and an increase in both cooking and purge loss. A lower chopping temperature reduced purge loss during chilled storage. In general, an inverse relationship was found between chopping temperature and penetration force. Chopping temperature did not influence total aerobic count, but during chilled storage counts were significantly higher in the low fat sausages.

Thermal gelation of meat batters as a function of type and level of fat and protein content

The rheological behaviour of meat batters during heating was analysed as a function of protein level (10–16%), type (pork back or perirenal/peritoneal fat) and amount (10–22%) of fat used. Fat thermal behaviour was studied by differential scanning calorimetry and rheological properties of batters were assessed using non-destructive measurements (thermal scanning rigidity monitor). The higher the protein content, the higher were the rigidity values displayed by the batters, irrespective of fat type, although the magnitude of these values appeared to be dependent on the amount and characteristics of the fat. The lower the fat content, the lower were the rigidity values of the batters. This behaviour pattern was influenced by the amount of protein present. In general, samples containing perirenal/peritoneal fat exhibited lower rigidity values at high temperatures, whereas at less than 35–40 °C, the opposite appeared to be the case.

Rheological changes during thermal processing of low-fat meat emulsions formulated with different texture-modifying ingredients

The rheological behaviour of high-fat (22%) and low-fat (8%) meat emulsions during thermal processing in the presence (3%) of various texture-modifying non-meat ingredients, namely maltodextrin, starch, wheat flour, egg white and apple fibre, was analysed. Rheological properties of emulsions were assessed using non-destructive measurements (thermal scanning rigidity monitor, TSRM). The lower the fat content, the lower were the rigidity values of meat emulsions throughout the temperature range studied. Emulsions made with maltodextrin proved less rigid. Addition of starch and egg white favoured the formation of more rigid structures in low-fat meat emulsions at temperatures over 55 °C. Low-fat meat batters containing wheat flour and apple fibre exhibited the highest rigidity values over the given temperature range. The presence of wheat flour caused variations in the modulus of rigidity at all stages of the thermal gelation process, very similar to those observed in high-fat emulsions.