Thermal Scanning Rigidity Monitor Research Articles

Thermal gelation behaviors of surimi protein mixed with Hydroxypropylmethylcellulose

This study examined the thermal galation characteristics of myofibrillar protein (MP) and salt-ground horse mackerel surimi that had been mixed with hydroxypropylmethylcellulose (HPMC). Analysis, using thermal scanning rigidity monitor and differential scanning calorimetry, demonstrated that thermal gelation begins in the thermo-reversible HPMC gel used in this study at approximately 60°C. In the rescanning test, first scanning diagrams showed similar pattern, but second scanning diagrams were rather diverse between MP and MP/HPMC mixture. The addition of HPMC increased rigidity of salt-ground surimi and modified the thermal gelation during the heating process, suggesting that certain enhancing effect of gelation occurred when the mixture of MP and HPMC was heated. In the annealing test, the addition of HPMC lowered the breaking force, but increased the gel strength of surimi due to a substantial increase in deformation. Although the strong cross-linking between the two components might not occur during the gelling process, HPMC gel formed at high temperature occupies some space in thermal gel by interacting with proteins and resulted in a combinative gel with a higher rigidity and gel strength at higher temperature.

Salt, Nonmuscle Proteins, and Hydrocolloids Affecting Rigidity Changes during Gelation of Giant Squid (Dosidicus gigas)

A thermal scanning rigidity monitor was used to determine how certain nonmuscle proteins and hydrocolloids contribute, separately or in combination, to gelation of giant squid mantle homogenized with 1.5% or 2.5% NaCl. In batters with 1.5% salt, rigidity was higher and peak gelation also took place at a higher temperature. Of all the ingredients tested, only ι-carrageenan contributed significantly to rigidity. Maximum values for batter rigidity and for folding test and work of penetration in cooked gels were attained when ι-carrageenan was added along with starch and a nonmuscle protein, which indicates synergy among the three ingredients. Keywords: Squid muscle; gelation; proteins; hydrocolloids; rheology

Thermal gelation properties of two different composition sardine ( Sardina pilchardus) muscles with addition of non-muscle proteins and hydrocolloids

A Thermal Scanning Rigidity Monitor was used to study heat gelation in two sardine minces (S1 and S2) differing in compositional properties (fat content (S1 = 4.3%, S2 = 9.6%) and water content (S1 = 76.5%, S2 = 72.0%)), protein functionality (soluble protein (S1 = 62.6%, S2 = 49.8%) and viscosity (S1 = 3140 cP, S2 = 2323 cP)), as well as the contribution to gelation of a number of non-muscle proteins (egg white, soy protein, sodium caseinate, wheat gluten) and hydrocolloids (iota-carrageenan and starch). The batter of the mince, characterised by higher protein solubility and viscosity and lower fat content (S1), exhibited greater structural stability at temperatures above 50 °C. The addition of gelling ingredients always produced an increase in maximum rigidity values, except in the case of sodium caseinate or starch-containing batters of mince with low protein solubility and viscosity (S2), where the rigidity is considerably inferior throughout the experimental temperature range. Of the non-muscle proteins assayed, batters contanining egg white presented the highest rigidity at maximum gelation peak, mainly in the low quality mince (S2). Iota-carrageenan also increased rigidity considerably with respect to the controls. Addition of starch gave less rigidity than iota-carrageenan, although it helped stabilise the formed gel at high temperatures (80 °C).

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 degrees 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.

Effects of different levels of fat on rheological changes and microstructure of meat batters during heat processing

The effect of differences in fat content (5.3% and 20.8%) on the rheological characteristics and microstructure of meat batters in the course of heating was studied. Rheological properties were assessed using nondestructive measurements (thermal scanning rigidity monitor) and structural failure (penetration test) analyses. Microstructure was studied by scanning electron microscopy (SEM). The influence of fat content on the modulus of rigidity (G) only became evident as gel structures began to form, giving higher G values for meat batters the higher the fat content of the sample. As the temperature was raised in the product (between 40 and 70° C), penetration stress and elasticity increased. The work of penetration, on the other hand, increased between 40 and 60° C, remaining steady at higher temperatures. Analysis of the results on the basis of different treatments indicates that an increase in fat content significantly raises penetration stress, elasticity and work of penetration. Increased temperature causes the formation of a matrix structure typical of heat-induced protein gels, which became compact and determine the formation of stronger, more elastic structures. Differences in microstructure caused by fat content were more evident at low temperature (40° C).

Rheological changes during thermal gelation of meat batters containing surimi from alaska pollack (Theragra chalcogramma) or sardine (Sardina pilchardus)

AbstractThe objective of this study was to use a thermal scanning rigidity monitor to analyse the changes occurring in rheological behaviour during thermal gelation induced by the presence of surimi in meat batters. These studies were conducted on systems prepared with pork meat to which varying proportions of surimi from Alaska pollack (Theragra chalcogramma (Pallas)) or sardine (Sardina pilchardus) (Walb) were added.The results indicated that gelation in pork proteins did not occur in the same way as in fish proteins. Whereas the addition of Alaska pollack surimi to the meat preparations produced scarcely any change with respect to the meat alone, the sardine surimi caused major alterations. These changes depended upon the proportion of protein from surimi added: addition of 100 g kg−1 caused a protein matrix to form, inducing the formation of stiffer gels and the appearance of the setting phenomenon, although at higher temperatures than are found with fish proteins. Such behaviour was not apparent when the proportion of protein from surimi was raised to 200 g kg−1.

Rheology of Sol‐Gel Thermal Transition in Cowpea Flour and Starch Slurry

ABSTRACTA thermal scanning rigidity monitor was used to follow rheological changes during heating of cowpea flour and starch slurries. The gelantinization temperature of cowpea starch was in the range 67–78°C. For cowpea flour, in addition to starch gelatinization, a shallow plateau was observed. The starch gelatinization onset temperature shifted from 67°C for starch to 72C for 25% cowpea flour that contained 12–15% starch. The modulus (G′) of cowpea gels increased with flour concentration according to a power relationship. Rigidity of the cowpea starch and flour gels decreased at temperatures higher than 78 and 87°C, respectively.

GELATION KINETICS of MEAT EMULSIONS CONTAINING VARIOUS FILLERS DURING COOKING

ABSTRACTA cylindrical shaped thermal scanning rigidity monitor (TSRM) was developed to determine shear rigidity modulus of meat batters during cooking. A meat fatprotein ratio of 1.8, moisture content of 62% and 8.6% filler were used. the fillers were buttermilk powder, corn starch, micro‐crystalline cellulose, modified corn starch, modified wheat flour, soy‐protein concentrate and whey‐protein concentrate. Plots of rigidity modulus versus product‐temperature showed two major thermal transitions. the first and most important transition (53 to 61°C) was due to myosin gelation. the second transition (64 to 69°C) was ascribed to the collagen softening. the maximum rigidity‐temperature slopes of 0.60 to 1.02 kPa/°C occurred after the first transition.

Effects of salt reduction on the rheological and gelation properties of beef, pork and poultry meat batters

The gelation and rheological properties of beef, pork and poultry meat batters as affected by salt reduction (2·50, 1·25 and 0·00%) were studied by using a Haake rotational viscometer and a thermal scanning rigidity monitor. Beef batters showed a decrease in shear stress with the decrease in salt levels at both high and low shear rates. Pork batter showed a mixed behavior (no definite trend in shear stress versus shear rate) and the poultry meat batters showed a Bingham pseudoplastic behavior, except for the no-salt treatment. During heating the beef batters showed the highest G values followed by the pork and the poultry meat batters. The rigidity modulus profiles exhibited two major transition temperatures at 47–53°C and at 64–76°C. Beef batter with 2·50% salt developed the highest average G value (16·6 kPa) and the poultry batter with 2·50% salt the lowest (7·3 kPa).

Thermal Transitions in Myosin‐ANS Fluorescence and Gel Rigidity

ABSTRACTThermal transitions (Tr) in myosin were monitored during constant rate heating with a thermal scanning rigidity monitor (TSRM) and a fluorescent probe, 1‐anilino‐naphthalene‐8‐sulfonate (ANS). The Tr values from fluorescent probe measurements were 37°C, 44°C, and 44°C for tilapia, rabbit, and chicken myosin‐ANS, respectively. Three Tr values at 43°, 49°C, and 55°C were observed in TSRM measurements of tilapia myosin gelation, whereas a single Tr was observed in rabbit and chicken gelation at 48°C and 49°C, respecitvely. In tilapia myosin, KCl concentration and pH significantly influenced the TSRM but not the fluorescence thermograms. These results indicated that a prerequisite change occurred in the hydrophobic character of myosin just prior to the onset of gelation.

Thermal Transitions of Admixed Starch/Fish Protein Systems During Heating

ABSTRACTThe thermal transitions of starch‐fish protein mixtures were investigated by a thermal scanning rigidity monitor technique and differential scanning calorimetry. Three transitions due to protein denaturation and one transition due to starch gelatinization were identified by both techniques during thermal processing of these mixtures. The gelatinization of starch caused an increase in rigidity of the system to a degree dependent upon the starch type. Thermal transitions of starch and fish protein seemed to proceed independently in mixture systems. However, the presence of salt and sucrose, necessitated by the inclusion of fish protein, caused starch gelatinization to shift to higher temperatures.

Thermally Induced Gelation of Selected Comminuted Muscle Systems–Rheological Changes during Processing, Final Strengths and Microstructure

ABSTRACTSols were prepared from comminuted fish (surimi), beef, pork and turkey muscles. Continuous evaluation of changes in structural rigidity and energy damping during heating of the sols from 3° to 95°C was performed in a nondestructive, temperature‐controlled Thermal Scanning Rigidity Monitor. Surimi presented major rigidity transitions at 40°. 48° and 65°C; beef at 43°. 56° and 69°C; pork at 44°, 53° and 69°C; and turkey at 50°, 53° and 79°C. All materials exhibited rapid decrease in energy damping (i.e. increase in elasticity) over a short temperature span. Failure testing of gels indicated differences in strength and deformability. SEM micrographs provided an insight into structural features of the gels.

Thermally Induced Gelation of Native and Modified Egg White‐Rheological Changes During Processing; Final Strengths and Microstructures

ABSTRACTThe heat‐induced gelation of native egg white (EW) and egg white modified with succinic anhydride (SEW) or oleic acid (OEW), by addition of 15 moles of reagent/50000g protein, was evaluated. Rigidity modulus (G) and mechanical energy damping were continuously monitored during heating of the samples from 5 ‐ 95°C in a nondestructive temperature‐controlled thermal scanning rigidity monitor (TSRM). A measurable increase in G and decrease in energy damping were observed at lower temperatures for OEW than for EW. In SEW the measurable rheological transitions occurred at the highest temperature ranges. Failure strength of the cooked products (gels) evaluated using torsion and uniaxial compression tests revealed large differences due to treatments. Micrographs of gels showed apparent structural differences among treatments.