Instron Hardness Research Articles

Assessment of Compressive Characteristics of Some Brands of Artemether – Lumefantrine Double Strength Tablets

The study was aimed at comparatively evaluating the mechanical properties of some brands of artemether lumefantrine double strength tablet (DST) products. The friability, hardness, disintegration tests, compressive stress, strain, extension and energy release at break of six randomly selected brands of DST products were evaluated using conventional pharmaceutical devices and engineering computerized Instron hardness tester. All the brands of the DST products passed the tablet friability test with values lower than 1% loss while one failed the disintegration test. Three brands exhibited hardness outcomes in the range of 1.30 to 3.26 KgF. Two brands gave energy release of 0.01 J while the others had 0 values at break. The plot of compressive stress and compressive strain for the products produce strikingly different pictogram patterns indicative of variable mechanical characteristics and drug release pattern (P<0.05). The DST formulations exhibited significant differences in their mechanical characteristics at break which could result in possible differences in their bioavailability outcomes (P<0.05). A standard operating procedure (SOP) is required to harmonize the outcomes of the mechanical characteristics of artemether lumefantrine DST formulations.

A new fast nonlinear modeling of soft tissue forsurgical simulation.

In this paper, soft tissue is modeled by a mass-spring-damper system and tissue deformations under the compression of surgical instruments are simulated. For this purpose, soft tissue confined in a cubic plastic mold is studied using a nonlinear viscoelastic model. Displacements resulting from probe insertions are measured and modeled for use in robotic surgery. Data is collected on bovine sirloin using the Instron hardness tester. The model's dynamic equations are obtained in the form of ordinary differential equations. The external force is considered as the input and the resulting deformation as the output of the model. Simulation results are compared with laboratory findings, and the nonlinear model's unknown parameters are estimated. The threshold force and displacement before the tearing of the soft tissue are respectively determined by analyzing the force-time and displacement-time diagrams obtained for the test samples.

Texture Profile of Tofu as Affected by Instron Parameters and Sample Preparation, and Correlations of Instron Hardness and Springiness with Sensory Scores

Our objective was to characterize the variations of tofu textural profiles as affected by physical parameters and to correlate the data with that of the sensory method. The textural profiles of 13 selected tofu types were characterized using various crosshead speeds and 2 degrees of penetration using an Instron universal textural machine. Hardness (firmness) and springiness (elasticity) were also analyzed by a descriptive sensory analysis. The results showed that the degree of plunger penetration had a significant impact on textural properties. Hardness values obtained by both levels of penetration correlated significantly (r= 0.94 to 0.95) with the sensory hardness. Springiness obtained by the 50% penetration method did not correlate significantly with the sensory data, whereas 75% penetration had a significant correlation (r= 0.98). Hardness values obtained using tofu specimens without skin correlated better with sensory data than that obtained with skin, which typically results from a pressing step in traditional tofu-making process. The findings were the first in the literature to show linear correlations between instrumental and sensory tofu textural characteristics, and provided a basis for the selection of physical parameters for determining tofu textural properties using an Instron machine.

CHARACTERISTICS OF FRANKFURTERS WITH DIFFERENT COOKING PARAMETERS

ABSTRACTThe purpose of this study was to evaluate the effects of different reheating methods (steeping, broiling, or microwaving) and end‐point reheating temperatures (66C, 77C, or 88C) on the physical and sensory characteristics of frankfurters. Instron hardness, shear force, sensory hardness, and saltiness scores increased and juiciness scores decreased with additional reheating temperature when frankfurters were microwaved or broiled. Frankfurter density decreased with higher ultimate temperature which was attributed to additional gas volume. Expressible moisture increased with a higher ultimate temperature when frankfurters were steeped. Free water was the highest at 77C. Neither cooking procedure nor ultimate temperature influenced protein denaturation as determined by gel electrophoresis and enzymatic digestion.

Gouda Cheese Made from Ultrafiltered Milk: Effects of Concentration Factor, Rennet Concentration, and Coagulation Temperature

The properties (composition, flavor, and texture) of Gouda cheese made from UF milk were evaluated to assess their dependence on the concentration factor, the rennet concentration, and the coagulation temperature employed in the manufacturing process. The UF Gouda had increased moisture content, decreased Instron hardness and decreased proteolysis compared to the conventional cheese. Milk concentration factors of 3.6 to 5 times were investigated. A 5 times concentration factor (80% volume reduction) yielded Gouda cheese more similar in moisture, Instron hardness, and proteolysis to the conventional Gouda cheese.Rennet concentrations of .007 to .021% based on unconcentrated milk volume were investigated. An intermediate rennet concentration (.014%) was found to be optimal Cheeses made using higher rennet concentrations were excessively bitter. Hence, savings in rennet costs of at least 33% in the manufacture of UF Gouda should be achievable.Bitterness was decreased by increasing the coagulation temperature. The increased temperature decreased PTA-soluble N, TCA-soluble N, and % NPN/TN, perhaps due to decreases in residual rennet. The coagulation temperature had no noticeable effects on cheese texture.

Some Grain Properties of IR36‐based Starch Mutants

AbstractSome grain properties of 20 starch mutants that were transferred from mutants of Japanese rices to IR36 (by two backcrosses to IR36) were studied. All had higher apparent amylose content (AC) and gelatinization temperature (GT) than the parent mutants, except the dull mutants, and the 82GF sugary mutant which had no amylose. All had lighter and lower density brown rices than IR36. Sugary 82GF und EM5 had high free sugars, and sugary and EM20 shrunken‐1 had high fat content. Phytoglycogen content of brown rice was 34% for 82GF and 7% for EM5 sugary mutants. Amylose extender mutants had higher lysine in brown rice protein than IR36 parent. Alkali spreading value did not accurately estimate GT of these starch mutants. Milled rice of the two high amylose extender mutants 2064 and EM16 had lower Amylograph peak viscosity but higher cooked rice Instron hardness than IR36 milled rice.

Effect of saline soil on grain quality of rices differing in salinity tolerance

Four varieties of rice, differing in salinity tolerance and grown in saline soil (electrical conductivity 5-6 dS/m) at Sadhoke, Punjab, Pakistan, had lighter grain and higher Na content than control samples. Grains of three out of the four rices grown on saline soils had higher brown rice protein (higher nutritional value), less translucent grain, lower starch and amylose content, and lower K than their control samples, but these differences were not related to salinity tolerance. Alkali spreading value and gel consistency were not affected by culture in saline soil. Cooked rice Instron hardness increased in saline culture in two higher-protein samples of the four rices. Amylograph peak viscosity was suppressed by saline culture.

Changes in Electrophoretic Patterns of Gadoid and Non‐gadoid Fish Muscle during Frozen Storage

ABSTRACTSodium dodecyl sulfate polyacrylamidc gel electrophoresis of fish muscle during frozen storage showed that a crosslinked protein of 280,000 daltons formed with gadoids, whereas this band did not occur with non‐gadoid fish species. For cod, 20 days at ‐7°C are needed for the crosslink to appear, whereas for whiting only 3 days arc needed. Formaldehyde (FA) may be responsible for the crosslinking. Adding ascorbic acid to cod mince prior to freezing accelerated dimcthylamine and FA formation during frozen storage and accelerated the formation of the crosslinked protein, while leaving cod fillets on ice for 10 days prior to freezing, reduced the Instron hardness and the crosslinked protein did not appear with 50 days of frozen storage at ‐7°C.

SENSORY AND INSTRUMENTAL EVALUATION OF TEXTURE OF COOKED AND RAW MILLED RICES WITH SIMILAR STARCH PROPERTIES

Three pairs of milled rices with similar starch properties (low gelatinization temperature waxy, and low gelatinization temperature low amylose, and intermediate gelatinization temperature intermediate amylose) were assessed for cooked rice properties by two industry taste panels and for raw and cooked rice properties by 30‐member Filipino consumer panels. Only slight differences in texture within pairs were noted by the two industry taste panels who had not been trained to assess boiled raw rice or waxy rice. The Filipino consumer panel gave significantly higher ranked scores for one low‐amylose variety in both raw and cooked forms. Malagkit Sungsong suman sa antala was ranked higher than modern waxy rices. Instrumental methods for translucency and whiteness of raw rice and Instron hardness and stickiness of cooked rice were not able to detect differences perceived by the Filipino consumer panels.

Effect of the hardening phenomenon on some physicochemical properties of common bean

Several aspects of the hard-to-cook phenomenon in beans ( Phaseolus vulgaris) were investigated. Two varieties of black and light yellow seeds were stored for 135 days at 40°C and 80% rh. Texture measurements produced force-time deformation curves of two peaks for the fresh samples and of three peaks plus a substantial increase in Instron hardness for the aged beans. The damaged starch content of the stored seeds tended to increase. The paste viscosity of flour dispersions from fresh seeds increased outstandingly after storage. Scanning electron microscopy studies showed that longitudinal sections of the cotyledons from hard beans had very densely packed cells, whereas they were loosely arranged in fresh samples. No changes were observed in the gelatinisation temperature of bean flour and isolated starch of hard-to-cook samples, as assessed by differential scanning calorimetry.

Barley Flour Level and Salt Level Selection for a Whole‐grain Bread Formula

ABSTRACTThual hull‐less barley from Alaska and Tennessee was ground into whole‐grain flours (10.5 and 14.4% protein, respectively). A potentially feasible bread formula was identified from response surfaces depicting effects of barley and salt levels within barley source on dough development parameters. Breads containing 20% barley, 30% whole‐wheat and 50% bread flours and 2.0% salt were prepared from each flour; a control contained 50:50 whole‐wheat:bread flour with 2% salt. Barley decreased specific loaf volume 5–6%. Instron hardness, cohesiveness, springiness, and chewiness were similar; lower protein barley bread was more gummy than the control. Overall flavor, appearance, and texture acceptability did not differ. Barley bread as prepared was feasible, suggesting the usefulness of response surfaces in formula development.

Varietal differences in properties of extrusion-cooked rice flour

Ten milled rices differing in starch properties were extrusion cooked through a twin screw extruder at 15% moisture and 120, 135 and 150°C. Instron hardness values of extrudate were lowest at 150°C. Extrusion cooking drastically reduced viscosity in 0·2 n KOH and in water without any decrease in amylose content and with little increase in reducing sugars. Spherical protein bodies were intact in the protein masses uniformly dispersed in the gelatinized starch matrix. Amylose content and gel consistency of raw rice flour were significantly correlated with expansion ratio only at 135°C, water absorption and solubility indexes at all temperatures and with gel viscosity of extrudates. Only gel consistency of raw flour correlated with cold paste viscosity of extrudate. Final gelatinization temperature of starch was not significantly correlated with any extrudate property.

MAJOR FACTORS AFFECTING COOKED MILLED RICE HARDNESS AND COOKING TIME

A study was made of factors affecting cooking time and the relationship between water:rice ratio (water content) in the rice cooker method and Instron hardness of cooked rice using 10 milled rice samples of diverse properties. Water:rice ratio for acceptable soft texture (&lt; 10 kg hardness) increased with increasing amylose content of the sample from 1.1 (56% water in cooked rice, wet basis) to 1.9 (68% water). The spread in cooked‐rice hardness values was higher at a water:rice ratio of 1.9 (68% water) than at 2.65 (75% water), which was equivalent to the water content of rice cooked in excess water for an optimum cooking time. Cooking time correlated better with starch final gelatinization temperature (r=0.75*) than with surface area per gram (r=−0.49) confirming the results of earlier kinetic studies that cooking rate was mainly influenced by the reactivity of the grain constituents with water.

Sensory Attributes of Corn Tortillas with Substitutions of Potato, Rice, and Pinto Beans

ABSTRACTCorn tortillas were prepared with substitutions of 12, 24, and 36% of two varieties of potato, 10, 20, and 30% of rice, and 5, 10, and 15% of pinto beans. Trained judges developed descriptors for appearance, aroma, manual and oral texture, flavor, and aftereffects, to quantify differences from the all‐corn reference. Up to 24% of either variety of potato, 30% of rice, and 15% beans could be substituted before undesirable sensory differences were detected. Potato improved texture, producing a softer, more flexible tortilla. Beans produced a less yellow, harder tortilla, and rice caused few sensory changes. Sensory texture compared well with Instron hardness and elongation measurements. Protein and lysine were unchanged by potato, increased by bean, and slightly decreased by rice substitution.