Optimisation of experimental conditions for binding of divalent iron to bioactive casein phosphopeptides

Casein phosphopeptides (CPPs) are mineral‐binding bioactive peptides derived from enzymatic digestion of casein. They have been shown to increase iron bioavailability due to increasing iron solubility at the alkaline pH of the intestine. Thus, they are potentially applicable as an advantageous preparation for iron fortification of food. This study aimed to characterise a commercially available CPP and determines optimum experimental conditions for binding it with ferrous iron. The effect of three variables – pH (5–7.5), mass ratio of iron to CPP (MR) (0.04–0.16) and holding time (40–80 min) – on the CPP's iron content was investigated using the central composite design (CCD) in response surface methodology (RSM), and a quadratic model was developed. The optimisation in this survey was based on the maximum response. Among all the regression's terms, the main and quadratic effects of pH represented the most significant influences on the iron content (P‐value <0.05). The obtained optimum conditions were as follows: pH 6.5, MR 0.14 and holding time 72 min, resulting in binding 68.66 mg iron per gram of the CPP. The quantity of iron bound to the CPP depended considerably on the experimental conditions and proved the importance of optimisation.     

Suppressing vibration modes of spindle-holder-tool assembly through FRF modification for enhanced chatter stability

Modifying dynamic response of a machine tool is of great importance for chatter mitigation. Tool tip frequency response function (FRF) can be suppressed by capitalizing on the absorber effect due to dynamic interactions among vibration modes of spindle, holder and tool. In this paper, a practical method is presented to modify the system’s FRF by selecting proper dimensions for assembly component without extensive testing. Robustness of the method is demonstrated through simulation and test results. Milling stability tests were also conducted where significant improvements in chatter free Material Removal Rate (MRR) is achieved.     

Evolving new group contribution-LSSVM model to estimate standard molar chemical exergy of pure organic substances

Chemical exergy values of pure organic compounds are required in order to perform an exergy analysis to achieve the optimum conditions. Development of reliable predictive tools for standard molar chemical exergy estimation, is of great importance. A least squares support vector machine (LSSVM) based group contribution (GC) method is proposed for standard molar chemical exergy prediction of pure organic compounds. The proposed model is trained and evaluated based on a comprehensive data base comprising standard molar chemical exergy for 133 organic compounds. 47 chemical substructures are employed in the process of model development. The proposed model is evaluated using different graphical and statistical error analysis. Determination coefficient (R²) and average absolute relative deviation (AARD%) values of 1.00 and 0.56% indicate the applicability potential and reliability of the predictions from the proposed model.     

Hesperetin-Loaded Solid Lipid Nanoparticles and Nanostructure Lipid Carriers for Food Fortification: Preparation, Characterization, and Modeling

Solid lipid nanoparticles and nanostructure lipid carriers were used to entrap hesperetin and broaden confined knowledge of application of nanocarriers as the functional ingredients in food sectors. The produced nanocarriers using a high mechanical shear method were subjected to size and zeta potential analysis. The developed nanosize carriers had the encapsulation efficiency ranging from 39.90 to 63.08 %. Differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy were also employed to study thermal behavior, crystalline state, and chemical structure. The release behavior of hesperetin in simulated gastrointestinal conditions was investigated and kinetically modeled. The modeling results indicated that the release phenomenon is mostly governed by combination of Fickian and dissolution mechanisms. Stability of the nanocarriers, as analyzed for up to 30 days, at 6 and 25 °C in aqueous suspension, showed no detectable hesperetin leakage. Cryoprotectant effect of different compounds (i.e., glucose, sorbitol, glycerin, lactose, and sucrose) was also examined. Finally, the potential capability of nanocarriers for food fortification was studied using milk as a model food. The fortified milk samples were subjected to sensory analysis and results betokened that the developed nanocarriers did not show any significant difference with blank milk sample and could well mask the bitter taste, after taste, and obviate poor solubility of hesperetin.     

Interpreting SuperPAVE PG test results with confidence intervals

The innovative method to interpret SuperPAVE PG test results using regression analysis and confidence intervals is evaluated in this research. Till now, most of researches and conclusions in the field of bitumen rheological aspects are based on the mean values of test results. Using the mean values does not show the reliability of the test results and in many cases two bitumen with the same PG show different performances, due to different data variances. In this study the confidence intervals method is implemented to interpret the results of SuperPAVE PG tests and notify that the mean values of the variables are occasionally misleading and always some uncertainty exists when using bitumen. This study presents a new formulation that quantifies the uncertainties in bitumen behavior to obtain the true temperature grade of the bitumen with different confidence levels (75% and 95%). Two samples of bitumen with same PG were evaluated with this formulation and the interesting results were found. The behavior of these samples with same PG was significantly different regarding the higher confidence intervals.