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Response Surface Analysis (response + surface_analysis)
Selected AbstractsOptimization of ingredients for the formulation of a direct acidified whey based lassi-like beverageINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2008KALYANI NAIR Samples of direct acidified whey based lassi like beverage were prepared with different proportions of guar gum, CMC and inulin and were examined for sensory and physical attributes. The optimisation was carried out using central composite rotatory design (CCRD) of response surface methodology (RSM). Response surface analysis revealed that sensory scores for flavour, consistency, colour and appearance and overall acceptability of lassi like beverage varied from 6.50 to 7.25, 6.16 to 7.12, 6.20 to 7.41 and 5.96 to 7.20 respectively. The results of analysis showed that all the examined model solutions had significant influence on the different parameters indicating that the statistical model designed for these attributes fitted well in all the aspects of model efficiency check (R2 >85%). [source] The impact of role discrepancy on nurses' intention to quit their jobsJOURNAL OF CLINICAL NURSING, Issue 9 2006BNurs, DipNurs, MNurs, Miyuki Takase RN Aims and objective., The purpose of this study was to investigate the impact of role discrepancy on nurses' intention to quit their jobs. Background., Nurses experience role discrepancy, which refers to incompatibility between the roles nurses desire and expect to take, and the roles they actually engage in at work. However, there is a paucity of information as to how this role discrepancy affects nurses' intention to quit their jobs. Design., A correlational design was used to investigate the impact of role discrepancy on nurses' intention to quit their jobs. Methods., A total of 346 Australian nurses participated in this study by completing questionnaires. The results were analysed by t -test, polynomial regression and response surface analysis. Results., Nurses tended to experience role discrepancy, in particular, in decision making with hospital policies and provision of patient education. The overall results show that this role discrepancy contributes to nurses' intention to quit their jobs. Nurses' intention to quit their jobs also increased when they had a low desire to engage in nursing roles and when they only performed a few roles. When specific dimensions of nursing roles were examined, a role discrepancy in the use of nursing skills, such as participation in decision making and providing patient education and emotional support, had little impact on their turnover intention. On the contrary, a role discrepancy in task delegation practice showed a significant association with nurses' intention to leave their jobs. Conclusions., Role discrepancy has been experienced by many nurses, and this discrepancy partially contributes to nurses' intention to quit their jobs. Relevance to clinical practice., To reduce nursing turnover, it is important to create a work environment where nurses are inspired to engage in various nursing roles and their work desires are reinforced by existing work opportunities. [source] OPTIMIZATION OF NATTOKINASE PRODUCTION CONDUCTION USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2006DJA-SHIN WANG ABSTRACT Natto has attracted worldwide attention because of its health benefits and long history in Japanese food. It has been found that a potent fibrinolytic enzyme named nattokinase, which is extracted from natto, is able to prevent atherosclerosis. The production of nattokinase may be influenced by various factors such as temperature, shaking speed, volume of medium, fermentation time and so forth. Three-step response surface methodology was applied to obtain the optimal operation conditions of the fermentation process in order to maximize the nattokinase yield. The three major steps are described as follows. First, the important factors for fermentation were identified by L8 orthogonal array experiment. The chosen factors were temperature (37 or 45C), shaking speed (110 or 150 rpm), volume of medium (80 or 120 mL), Brix of wheat bran extract (1.5 or 3°), Brix of soy meal extract (1 or 2°), glucose concentration (0.6 or 1.2%) and fermentation time (24 or 36 h). Second, a regression equation was established between the response (i.e., the enzyme activity) and the two statistically significant factors (i.e., the volume of medium and fermentation time). Third, the optimal solutions for the volume of medium and fermentation time were obtained based on the response surface of the regression equation. According to the response surface analysis, the optimal operation conditions for the fermentation process should be 80 mL and 37.0817 h for the volume of medium and the fermentation time, respectively, which resulted in 459.11 FU/mL as the predicted enzyme activity. [source] EFFECTS OF PROCESS VARIABLE CONDITIONS ON MINERAL AND CHEMICAL COMPOSITION OF EXTRUDED AFRICAN BREADFRUIT (TRECULIA AFRICANA DECNE) MIXTURESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2009TITUS U. NWABUEZE ABSTRACT Five levels of African breadfruit (Treculia africana), corn and soybean mixtures (fc) in ratios of 40:5:55, 55:5:40, 70:5:25, 85:5:10 and 100:0:0, respectively, were hydrated to 15, 18, 21, 24 and 27% (fm) and extruded at 100, 120, 140, 160 and 180 rpm (ss) in a Brabender single-screw extruder. The objective was to study effects of process variable conditions on mineral and chemical composition of the mixtures. Models developed by response surface analysis were high (R2 = 0.7646,0.9732) for Na, Ca, Mg, protein, fat, fiber and carbohydrate, and showed no significant (P > 0.05) lack of fit. All process variables had significant (P , 0.05) linear effects on Mg, protein and carbohydrate, quadratic effects on fat, energy and Mg and cross-product effects on Ca, Mg, protein and carbohydrate, when fc interacted with either fm or ss. Optimum process variable conditions that gave the best mineral and chemical composition were obtained at 40:5:55(fc), 18% (fm) and 140 rpm (ss). PRACTICAL APPLICATIONS The potentials of African breadfruit as a nutrient resource and its position in the food cycle of the people in the subtropical African countries makes its blending with other local ingredients one important way of expanding the scope of its utilization. African breadfruit seeds provide a delicacy and a specialized meal when consumed alone or with shelled milk-corn. The versatility and acceptance of extrusion as a processing technology and its benefits over conventional methods and worldwide adaptability to a variety of crops, makes its application in this research appropriate. Optimization of process variable conditions affecting mineral and chemical composition of extruded and unextruded mixtures of African breadfruit, corn and soybean, using response surface analysis, was the thrust of the study. It is expected to produce an optimum process combination that could give the best mineral and chemical composition for a possible scale-up operation in African breadfruit seed processing enterprises. [source] EXTRUSION COOKING OF BLENDS OF SOY FLOUR AND SWEET POTATO FLOUR ON SPECIFIC MECHANICAL ENERGY (SME), EXTRUDATE TEMPERATURE AND TORQUEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2001M. O. IWE Defatted soy flour and sweet potato flour containing 18% moisture were mixed in a pilot mixer, and extruded in an Almex-Bettenfeld single-screw extruder operated at varying rotational speed and die diameter. A central composite, rotatable nearly orthogonal design, which required 23 experiments for three factors (feed composition (fc), screw speed (ss) and die diameter (dd)) was developed and used for the generation of response surfaces. Effects of the extrusion variables on specific mechanical energy (SME), extrudate temperature (ET), and torque (T) were evaluated using response surface analysis. Results showed that product temperature increased with increases in die diameter, screw speed and feed composition. However, the effect of die diameter was greater than those of screw speed and feed composition. Decrease in die diameter with increase in sweet potato content increased torque. Screw speed exhibited a linear effect on torque. [source] PHYSICAL CHARACTERISTICS AND ACCEPTABILITY OF EXTRUDED AFRICAN BREADFRUIT-BASED SNACKSJOURNAL OF FOOD QUALITY, Issue 2 2008TITUS U. NWABUEZE ABSTRACT Five-level combinations of African breadfruit, corn and soybean, in the ratios 40:5:55; 55:5:40; 70:5:25; 85:5:10 and 100:0:0%, respectively, were hydrated to 15, 18, 21, 24 and 27% and extruded into snacks at screw speeds of 100, 120, 140, 160 and 180 rpm. Physical characteristics of snacks from blends containing 15 and 18% moisture ranged from thin-smooth to thin-fine-smooth pellets. Those containing 21 to 27% moisture were either thin-smooth or thick-smooth, fine-smooth or rough strands. Feed moisture and feed composition were the most significant process variables influencing physical and sensory characteristics. The optimum process variable combination that had maximum influence on physical and sensory characteristics of snacks was the 70:5:25 feed ratio with 21% moisture and extruded at 140 rpm. This resulted in an overall acceptability score of 8.20 on a 9-point hedonic scale. PRACTICAL APPLICATIONS African breadfruit is widely grown in the high rainforest parts of Nigeria and other African countries, where the seeds are traditionally consumed as porridge meal when cooked with ingredients or as snacks when roasted. There is therefore a need to adopt more efficient extrusion technologies to rapidly and efficiently transform African breadfruit and its blends with corn and soybean into acceptable snacks. Optimizing process variable conditions using response surface analysis to evaluate product physical characteristics and acceptability was the thrust of this study. It is expected to give direction toward a more scientific approach to scaling up operations in African breadfruit seed processing and utilization. [source] THE EFFECT OF EXTRUDED FLOUR AND FERMENTATION TIME ON SOME QUALITY PARAMETERS OF IDLIJOURNAL OF FOOD QUALITY, Issue 1 2000KULWINDER KAUR ABSTRACT The effects on idli characteristics of fermentation time and substituting rice with differing proportions of rice flour extrusion-cooked under different conditions were studied. The specific gravity, pH and viscosity of batter and idli characteristics such as expansion, compression force and sensory attributes were measured and described using regression to fit a response surface analysis. Fermentation time showed the most pronounced effect on specific gravity, pH and aqueous dispersion viscosity of batter and taste scores of idli. Substituting rice flour with extruded rice flour at different levels were observed to have significant effect on expansion and appearance scores of idlis. The textural scores and compression force was significantly affected by extrusion temperature. The formulation containing rice substituted by 30% extruded rice flour extruded at 175C and fermented for 24 h produced idlis with highest expansion and overall acceptability. [source] Likelihood and bayesian approaches to inference for the stationary point of a quadratic response surfaceTHE CANADIAN JOURNAL OF STATISTICS, Issue 2 2008Valeria Sambucini Abstract In response surface analysis, a second order polynomial model is often used for inference on the stationary point of the response function. The standard confidence regions for the stationary point are due to Box & Hunter (1954). The authors propose an alternative parametrization, in which the stationary point is the parameter of interest; likelihood techniques and Bayesian analysis are then easier to perform. The authors also suggest an approximate method to get highest posterior density regions for the maximum point (not simply for the stationary point). Furthermore, they study the coverage probabilities of these Bayesian regions through simulations. Approches vraisemblantiste et bayésienne pour I'inference portant sur le point stationnaire d'une surface de réponse quadratique Résumé: Dans l'analyse des surfaces de réponse, un polyn,me du second degré est souvent utilisé pour l'inférence portant sur le point stationnaire de la fonction de réponse. Les régions de confiance standards pour le point stationnaire sont dues à Box & Hunter (1954). Les auteurs proposent une paramétrisation différente dans laquelle le point stationnaire est le paramètre d'intér,t; ceci facilite l'emploi des techniques de vraisemblance et l'analyse bayésienne. Les auteurs suggèrent aussi une façon d'approximer les régions de plus haute densité a posteriori pour le point maximum (et non seulement pour le point stationnaire). De plus, ils étudient les propriétés de couverture des régions bayésiennespar voie de simulation. [source] Combination treatment with telmisartan and hydrochlorothiazide in black patients with mild to moderate hypertensionCLINICAL CARDIOLOGY, Issue 1 2001Janet B. Mcgill M.D. Abstract Background: Hydrochlorothiazide (HCTZ) is commonly used to treat black patients with hypertension. To avoid the metabolic disturbances associated with high-dose HCTZ, blood pressure control may be achieved by combining low doses with another antihypertensive. Hypothesis: The study was undertaken to assess the tolerability and antihypertensive dose-response efficacy of telmisartan and HCTZ and their combination in black patients with mild to moderate hypertension (mean supine blood pressure 140/95-200/114 mmHg). Methods: Following a 4,week, single-blind, placebo run-in period, 222 black patients were randomized to once-daily treatment with one of 20 different double-blind combinations of telmisartan (0, 20, 40, 80, 160 mg) and HCTZ (0, 6.25, 12.5, 25 mg) for 8 weeks. Blood pressure was measured at baseline and after 2, 4, and 8 weeks. Results: Telmisartan 80 mg/HCTZ 12.5 mg reduced supine trough diastolic blood pressure (DBP),primary efficacy parameter,by 13.3 mmHg, and supine trough systolic blood pressure (SBP) by 21.5 mmHg. These reductions represented benefits of 13.7/8.7 mmHg over telmisartan 80 mg and 12.3/8.1 mmHg over HCTZ 12.5 mg(p<0.01). Telmisartan 40 mg/HCTZ 12.5 mg reduced supine trough SBP/DBP by 14.3/10.0 mmHg, amounting to 12.3/3.3 mmHg more than telmisartan 40 mg and 5.1/4.8 mmHg more than HCTZ 12.5 mg, This reached significance for the comparisons with telmisartan 40 mg for SBP and HCTZ 12.5 mg for DBP (p,0.05). A response surface analysis and therapeutic response rates confirmed the additive antihypertensive effects of telmisartan and HCTZ. All treatments were well tolerated, with side-effect profiles comparable with placebo. Adverse events were mainly transient and of mild to moderate severity. Conclusions: Telmisartan 80 mg combined with HCTZ 12.5 mg is effective and well tolerated in black patients with mild to moderate hypertension, providing greater antihypertensive activity than the corresponding monotherapies. [source] | |||||||||||||