Reduced Fat, High Moisture Beef Frankfurters as Affected by Chopping Temperature

Six treatment combinations were studied to determine the effects of initial temperature (0, 15, 30°C) and endpoint chopping temperatures (0, 15, 30, 45°C) on texture and stability of reduced fat, high moisture beef frankfurters. Textural properties (raw batter, frankfurter) and purge loss were determined over 8 wk storage. As endpoint chopping temperature increased, batter stability and shear force decreased. In most samples, initial temperature did not affect texture or stability. Endpoint chopping temperatures of ± 15°C resulted in most stable batters. Chopping > 15°C lowered product quality.     

Fracture of Alaska Pollock Gels in Water: Effects of Minced Muscle Processing and Test Temperature

The effects of temperature on instrumental textural measurements of cooked Alaska pollock gels were evaluated. Independent variables were: raw materials (minced muscle, washed minced muscle alone or with cryoprotectants), cooking schedule (90°C for 20 min with/without preconditioning at 25°C) and test temperatures. Gels tested at 5°C were more brittle than those tested at 45–55°C. Gels preset at 25°C for 1 hr prior to cooking at 90°C had higher fracture shear stress values and were influenced differently by test temperatures than those not preset suggesting cooking history influenced structure of the gels at the molecular level. Results indicated gels set at 25°C were probably stabilized by more covalent bonds.     

Electrical Stimulation of Mutton

Electrically stimulated ovine muscles, restrained from shortening during rapid chilling at 0-1 or 15-16°C, had lower Warner-Bratzler (WB) shear force values after 1 and 2 days aging at 0-1°C than un-stimulated controls, but were not significantly different at ≥4 days aging. Direct measurement of muscle fiber length showed that contraction values obtained for muscles assigned to go into rigor at 0, 15, 30 or 40°C were significantly less for stimulated muscles than for control muscles at 0°C, but of same magnitude or at rigor temperatures ≥15°C. WB shear force values indicated that, at temperatures ≥15°C, increase in tenderness due to stimulation became small after 7 days aging at 0-1°C, whereas at 0°C aging further increased improvement due to stimulation. Results were thus consistent with electrical stimulation reducing myofibrillar shortening at rigor temperature <15°C but at temperature ≥15°C stimulation had the same effect as a few days aging.     

Setting Response of Alaska Pollock Surimi Compared with Beef Myofibrils

Physicochemical properties of surimi after preincubation at 25–50°C and beef myofibrils at 25–60°C for up to 8 hr prior to cooking at 80°C for 20 min were evaluated by a torsion test and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Shear stress and true shear strain of surimi were more sensitive to pH changes than beef myofibrils. Maximum gel strength was found at = pH 7 for surimi and pH 6 for beef myofibrils. The myofibrils showed no setting effect at any preincubation temperatures examined, while surimi showed an optimum setting effect at 25°C. Incorporation of beef myofibrils into surimi resulted in decrease of shear stress and true shear strain values.     

Comparison of the Thermostability of Red Hake and Alaska Pollock Surimi during Processing

Thermostability of red hake (Vrophycis chuss) mince and its temperature-dependent gel-forming properties were determined while using Alaska pollock (Theragra chalcogrumma) for comparison. Fish mince and surimi were subjected to various washwater, chopping and setting/ cooking temperatures, cooking times at varying salt concentrations and moisture levels. The optimal temperatures for washing and chopping were 15°C and 12°C for red hake and 10°C and 4°C for pollock, respectively. All treatments significantly affected gel properties. For red hake gels, 77% moisture, 2.0% salt, and a 40°C preheat-setting temperature produced the most cohesive gel. Gels of both red hake and pollock gradually became less cohesive with extended cooking time. The results suggest that red hake is more thermally stable than pollock.     

Relationship of Disulfide Bond Formation to Altered Rheological Properties of Oleic Acid Modified Egg White

Egg white modification with oleic acid (OEW) had no effect on disulfide bond formation during the thermal gelation process. Lower transition temperatures were seen for oleic acid treated egg white (70°C) relative to native egg white (EW) (74°C). Torsional failure testing showed increases of 60 and 100% for shear stress and strain at failure, respectively, of OEW over EW. Dialysis, pH-adjustment, and treatment with N-ethylmaleimide (NEM) lowered stress values while shear strain Was affected only by pH-adjustment. Scanning electron micrographs indicated a more dense structure for OEW than that of EW. No visible structural change was apparent due to treatment with NEM.     

Physical Characteristics of Surimi Seafood as Affected By Thermal Processing Conditions

Texture, color and microbiological characteristics of surimi seafood were measured at three processing temperatures (93°, 85°, and 75°C) and various times (0–120 min). The time required to provide a zero aerobic plate count at 93°, 85°, and 75°C was 5,15, and 15 min, respectively. Both thermal processing temperature and time affected whiteness and shear strain of surimi seafood. As the thermal processing temperature and time increased, the shear strain and whiteness decreased. The higher the thermal processing temperature and longer time, the lower were the shear strain and whiteness. Results indicated 15 min at 75° or 85°C were the optimum thermal processing conditions.     

Ca2+-Induced Gelation of Pre-heated Whey Protein Isolate

Addition of CaCl₂ to pre-heated whey protein isolate (WPI) suspensions caused an increase in turbidity when pre-heating temperatures were ≥ 64°C. Pre-heating to ≥ 70°C was required for gelation. WPI suspensions which contained CaCl₂ became turbid at 45°C and formed thermally induced gels at 66°C. Thermally and Ca²⁺-induced gels showed significant time/temperature effects but the penetration force values in the Ca²⁺-induced gels were always lower. However, Ca²⁺-induced gels were higher in shear stress at fracture. The Ca²⁺-induced gels had a fine-stranded protein matrix that was more transparent than the thermally induced gels, which showed a particulate microstructure.     

Hot-boning, Tumbling, Salt and Chopping Temperature Effects on Cooking Yield and Acceptability of Emulsion-type Pork Sausage

Hot-boned or chilled pork with addition of 2% or 3% salt was used to prepare emulsion-type pork sausage. Different tumbling periods and a variety of chopping temperatures were evaluated. Emulsifying capacity (EC), water-holding capacity (WHC), pH, total plate count (TPC) and organoleptic properties were determined. Hot boned pork with 3% added salt had higher EC, pH, WHC, cooking yield and lower TPC than chilled meat samples with 2% added salt. As chopping temperature increased, WHC decreased and TPC increased. However, an intermediate chopping temperature of 12.8°C produced superior yield.     

Effect of Different Processing Methods and Salt Content on the Physicochemical and Rheological Properties of Meat Batters

The physicochemical and rheological properties of raw and cooked batters produced by a chopping or beating process with various amounts of salt content were studied. Various meat batters were made up for this purpose: the batter processed by chopping with 2% salt, by beating with 1% salt and 2% salt, respectively. Compared with the chopping, the beating cooked batters had higher L* value, hardness, G’ value at 80°C, and lower cooking loss. Using the beating process, the batter with 1% salt had lower L* values, hardness, springiness, and higher cooking loss than the 2% salt. From the micrographs, the batters produced by beating process exhibited more uniform and compact microstructure than the chopping. The result of low-field nuclear magnetic resonance exhibited that the batters of beating had higher water holding capacity than the chopping. Overall, the beating process enabled lowering of the salt content, cooking loss, and making the cooked batter more hard and elastic.     

Effect of Temperatures on Fish Alkaline Protease, Protein Interaction and Texture Quality

The effect of the activity of fish alkaline protease and protein denaturation on texture changes in mullet muscle during heating were studied. The proteolytic enzyme and the urea denatured hemoglobin substrate were incubated at different pH values and various temperatures. The enzyme activity was optimal at pH 8 and at 65°C. The extent of protein-protein interactions in mullet actomyosin solutions increased with increasing temperature. The rate of protein-protein interactions increased sharply as temperature increased from 35°C to 45°C at pH 6. When mullet muscle was heated at various temperatures ranging from 55°-85°C, the shear force value increased (toughening) during the initial stage of heating and then decreased (softening). The toughening of fish flesh is probably due to muscle protein interactions, and the later tenderizing of fish flesh may be explained by alkaline protease activity (hydrolysis) masking the protein denaturation effect. When fish flesh was cooked at 100°C, no tenderizing effect was observed. This was probably due to loss of enzyme activity and only protein denaturation had significant effect on texture quality.     

Rheology of Rice Starch‐Sucrose Composites

The effect of sucrose at different concentrations (0, 10, 20 and 30%) on rheological properties of rice starch pastes (5% w/w) was investigated in steady and dynamic shear. The steady shear properties of rice starch‐sucrose composites were determined from rheological parameters for power law and Casson flow models. At 25°C all the starch‐sucrose composites exhibited a shear‐thinning flow behavior (n=0.25–0.44). The presence of sucrose resulted in the decrease in consistency index (K), apparent viscosity (η_a,100) and yield stress (σ_oc). Dynamic frequency sweeps at 25°C indicated that starch‐sucrose composites exhibited weak gel‐like behavior with storage moduli (G′) higher than loss moduli (G′′). G′ and G′′ values decreased with the increase in sucrose concentration. The dynamic (η*) and steady‐shear (η_a) viscosities at various sucrose concentrations did not follow the Cox‐Merz superposition rule. G′ values as a function of aging time (10 h) at 4°C showed a pseudoplateau region at long aging times. In general, the values of G′ and G′′ in rice starch‐sucrose composites were reduced in the presence of sucrose and depended on sucrose concentration.     

Characterization of Extruded and Toasted Milk Protein Concentrates

Important functional properties of milk protein concentrate with 80% protein (MPC80), modified with low‐ and high‐shear extrusion, or low‐temperature toasting were compared. The effect of high‐ and low‐shear profile screws in a corotating twin‐screw extruder, and 4 different ramped temperature profiles with die temperatures of 65, 75, 90, and 120 °C were compared. Extrudates were pelletized, dried, and ground to a fine powder. Toasting was done at 75 and 110 °C for 4 h for milk protein modification. Extruded and toasted MPC80 had reduced protein solubility and surface hydrophobicity. Extrusion decreased water‐holding capacity (WHC). Toasted MPC80 had increased WHC when treated at 75 °C, but WHC decreased when heated at 110 °C. The treatments had no strong influence on gel strength. Reduced and nonreduced sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed peptide structural changes that occurred due to processing, especially for whey proteins. Results are discussed in terms of potential for application of extruded or toasted MPC80 in high‐protein nutrition bar applications.     

Effects of Collagen and Alkaline Phosphate on Time of Chopping, Emulsion Stability and Protein Solubility of Fine-Cut Meat Systems

Four meat emulsions were prepared with two levels of collagen and alkaline phosphate. Samples were taken at five different chopping temperatures and evaluated for total chopping time, emulsion stability and protein solubility. Adding additional collagen to meat emulsions shortened total chopping time, and decreased emulsion stability but had no effect on protein solubility. The addition of 0.25% sodium tripolyphosphate (STPP) improved emulsion stability but resulted in no significant (p>0.05) change in chopping time or protein solubility. The high-collagen-phosphate (HCP) treatment resulted in less fat, gelliquid, solid and total cookout when compared with high-collagen no-phosphate (HC) and low-collagen no- phosphate (LC) treatments. Maximum emulsion stability was obtained at 13°C.     

Freezing and Thawing Conditions Affect the Gel Stability of Different Varieties of Rice Flour

The freeze‐thaw stabilities of three different rice flour gels (amylose rice flour with 28% amylose, Jasmine rice flour with 18% amylose and waxy rice flour with 5% amylose) were studied by first freezing at –18 °C for 22 h and subsequent thawing in a water bath at 30 °C, 60 °C and 90 °C, or by boiling in a microwave oven. The freeze‐thaw stability was determined for five cycles. Starch gels thawed at higher temperature exhibited a lower syneresis value (percent of water separation) than those thawed at lower temperature. Amylose rice flour gels gave the highest syneresis values (especially at the first cycle). The Jasmine rice flour gels gave a higher syneresis value than the waxy rice flour gel. Except for freezing by storage at –18 °C and thawing at 30 °C, there was no separation of water at any cycle when waxy rice flour gel was thawed at any temperature, irrespectively of the freezing methods used. Cryogenic Quick Freezing (CQF) followed by storage at –18 °C and then thawing (by boiling or by incubation at any other temperatures) gave lower syneresis values than all comparable samples frozen by storage at –18 °C. The order of syneresis values for the three types of rice flour was waxy rice flour < Jasmine rice flour < amylose rice flour. The syneresis values and the appearance of starch gels, which had gone through the freeze‐ thaw process, suggested that the order of freeze‐thaw stability of gels for the three types of rice flour was waxy > Jasmine > amylose rice flour.     

Optimisation of a Mashing Program for 100% Malted Buckwheat

The objective of this study was to develop a temperature programmed mashing profile for 100% buckwheat malt. Both standard brewing methods and a rheological tool (Rapid Visco Analyser) were used to characterise worts and mashes. An optimal grist: liquor ratio of 1:4 was observed. At this ratio, buckwheat malt showed a gelatinisation temperature of 67°C and barley malt 62°C. A one hour stand at 65°C exhibited higher FAN levels, fermentable extracts and lower viscosity values than stands at 67°C or 69°C, and was therefore used in further mashing trials. An extra mashing step of 30 min, at any of the tested temperatures, increased extract values a minimum of 4%, decreased viscosities a minimum of 0.20 mPas, and increased fermentable extracts 12%. Best results were obtained when a mashing‐in temperature was used in the range of 35°C to 45°C. These mashing‐in temperatures were used to design an optimal mashing procedure: 15 min at 35°C; 15 min at 45°C; 40 min at 65°C; 30 min at 72°C; 10 min at 78°C. This program showed higher extract values and fermentable extract values (72.7% and 49.9%) than obtained by congress mashing (65.3% and 40.0%), thus successfully optimising the mashing program.     

Effect of pre‐ripening chilling temperatures on ripening,shelf life and quality of bananas treated with 1‐methylcyclopropene

Ethylene production, shelf life and fruit quality of Cavendish bananas (cv. Williams), held at different pre‐ripening storage temperatures (5 °C, 10 °C or 15 °C) prior to ethylene and/or 1‐methylcyclopropene (1‐MCP) application, were determined and compared. Levels of ethylene production during ripening were highest for control fruit that had been stored at 5 °C followed by 10 °C and then 15 °C. 1‐MCP treatment (at 300 nL L^?1) had no effect on ethylene production of fruit that had been stored at 10 °C by day 10 of storage, but ethylene production was significantly higher for fruit that had been stored at 15 °C and lower for those stored at 5 °C before 1‐MCP treatment. 1‐MCP also increased shelf life to a greater extent when applied to fruit that had been stored at 10 °C or 15 °C. Even though 1‐MCP had no significant effect on under peel chilling injury, it increased discolouration significantly, regardless of storage temperature. Firmness of 1‐MCP‐treated fruit decreased significantly compared to the control when fruit were held at 5 °C or 15 °C prior to ripening (and 1‐MCP application) but had no effect on fruit stored at 10 °C before ripening. These results indicate that pre‐ripening storage temperature affects ripening, shelf life and quality in both ethylene and 1‐MCP‐treated bananas.     

Reduction of Drying Time for Pepperoni by Vacuum-drying

Commercial pepperoni was dried under vacuum (100 kPa) at three temperatures (177°, 19°, and 22°C) and matching controls were dried under commercial conditions. Vacuum-dried pepperoni achieved a moisture: protein (M:P) ratio of 1.6:1 after 9 to 12 days drying, compared to 18 days for the control. Overall drying time was reduced ～30%. Among temperature treatments, 17°C treatment had more weight loss and darker color (P < 0.05) than others. Weight loss and Kramer shear force were higher (P < 0.05) for vacuum-dried pepperoni, whereas Hunter a and b values tended to be higher for the control throughout the drying period.     

Rheological Characterization of Commercial Baby Fruit Purees

The rheological behaviour of fruit purees was measured at different temperatures (20°C–40°C) in a rotational viscometer. The rheograms were fitted with the Power Law or Ostwald de Waele model, the Herschel-Bulkley model, the Casson model, and the Cross model. The best adjustment was obtained with the Cross model, except for systems fruit purees 2 and 4, which were fitted satisfactorily with Power Law model. Flow curves exhibited at all temperatures a pseudoplastic character after applying a shear stress higher than a critical value.     

Fat Level and Freezing Temperature Affect Sensory, Shear, Cooking and Compositional Properties of Ground Beef Patties

Experiments were conducted to determine effects of two targeted fat levels (6, 20%) and two freezing temperatures (?43, ?20°C) on sensory, shear, cooking and compositional properties of beef patties. Select grade beef rounds (IMPS 161) were used as the lean source for patties with U.S. Choice plates as the fat source. The 20% fat formulation had increased beef flavor and initial tenderness (?20°C frozen patties only) scores, but had higher instrumental shear values compared to the 6% fat patties. Freezing patties (especially those of 6% fat) at ?43°C greatly improved sensory and instrumental tenderness. Faster freezing reduced fat retention of 20% fat patties during cooking. Use of Select grade beef rounds coupled with rapid freezing is suggested for producing acceptable low-fat ground beef patties.