Antioxidant effects of soy sauce on color stability and lipid oxidation of raw beef patties during cold storage

This study was conducted to evaluate the antioxidant effects of soy sauce on lipid oxidation and color stability of raw beef patties. Raw beef patties were formulated with four solutions such as NaCl (sodium chloride solution), NaCl/SS (1:1 ratio of sodium chloride and soy sauce solution), SS (soy sauce solution), or SS/A (soy sauce solution combined with 0.05% ascorbic acid) in the same salt concentration. Addition of soy sauce resulted in the decreased pH, lightness, and increased yellowness. Treatment SS/A had the lowest percent of metmyoglobin during storage (P < 0.05). A reduction (P < 0.05) in the 2-thiobarbituric acid, peroxide, and conjugated diene concentration as result of soy sauce addition were observed in treatments SS and SS/A at the end of the storage period. There were no differences (P > 0.05) in free fatty acid concentration at the end of storage. The combined addition of soy sauce and ascorbic acid greatly improved (P < 0.05) color stability and retarded lipid oxidation.     

Antioxidative properties of onion peel extracts against lipid oxidation in raw ground pork

Onion peels extracted with various concentrations of ethanol were examined for their extraction yield, total phenolic content, DPPH scavenging activity, and reducing power. Onion peel extracted with 50% ethanol exhibited higher extraction yields, total phenolic content, and DPPH scavenging activity than extracts from distilled water, 70 or 95% ethanol. Thus, the antioxidative efficiency to inhibit lipid oxidation of ascorbic acid (0.05%) and 50% ethanol extract of onion peel (0.05, 0.1, and 0.2%) in raw ground pork was investigated during chilled storage (16 days). The pH of the samples decreased considerably during storage (p<0.05). Addition of ethanol onion peel extract significantly improved the thiobarbituric acid reactive substances and peroxide values in raw ground pork meat (p<0.05). Therefore, onion peel extract by 50% ethanol is a very effective inhibitor of lipid oxidation and has potential as a natural antioxidant in raw ground pork.     

Characterization of plasma electrolytic oxide formed on AZ91 Mg alloy in KMnO4 electrolyte

The aim of this work is to investigate microstructure, corrosion resistance characteristics and nanohardness of the oxide layer on AZ91 Mg alloy by applying different voltage with KMnO₄ contained solution. There are lots of closed pores that are filled with another oxide compound compared with the typical surface morphology with pore coated until 350 V of coating voltage. The thickness of oxide layer increases with increasing coating voltage. The oxide layer formed on AZ91 Mg alloy in electrolyte with potassium permanganate consists of MgO and Mn₂O₃. Corrosion potential of the oxide layer on AZ91 Mg alloy obtained at different plasma electrolytic oxidation(PEO) reaction stages increases with increasing coating voltage. The corrosion resistance of AZ91 Mg alloy depends on the existence of the manganese oxide in the oxide layer. The inner barrier layer composed of the MgO and Mn₂O₃ may serve as diffusion barrier to enhance the corrosion resistance and may partially explain the excellent anti-corrosion performance in corrosion test. Nanohardness values increase with increasing coating voltage. The increase in the nanohardness may be due to the effect of manganese oxide in the oxide layer on AZ91 Mg alloy coated from electrolyte containing KMnO₄.     

Effects of fat levels on changes in flavor pattern of irradiated pork patties

The effects of fat levels on changes in flavor pattern of irradiated pork patties were evaluated by using electronic nose. Total peak amount decreased with increasing fat level and irradiation dose, and the increased fat level and irradiation dose influenced the formation of new peaks at latter retention time. For the principal component analysis, the irradiated pork patties with containing higher fat level were clearly separated from the other treatments. The irradiation dose also affected the position of spot in identical fat level. It is possible to distinguish the changes in flavor patterns due to fat content and irradiation dose by using electronic nose.     

A robust optimization using the statistics based on kriging metamodel

Robust design technology has been applied to versatile engineering problems to ensure consistency in product performance. Since 1980s, the concept of robust design has been introduced to numerical optimization field, which is called the robust optimization. The robustness in the robust optimization is determined by a measure of insensitiveness with respect to the variation of a response. However, there are significant difficulties associated with the calculation of variations represented as its mean and variance. To overcome the current limitation, this research presents an implementation of the approximate statistical moment method based on kriging metamodel. Two sampling methods are simultaneously utilized to obtain the sequential surrogate model of a response. The statistics such as mean and variance are obtained based on the reliable kriging model and the second-order statistical approximation method. Then, the simulated annealing algorithm of global optimization methods is adopted to find the global robust optimum. The mathematical problem and the two-bar design problem are investigated to show the validity of the proposed method.     

Powder Characteristics of Pb(Mg1/3Nb2/3)O3 Prepared by Molten Salt Synthesis

Lead magnesium niobate (Pb(Mg_1/3Nb_2/3)O₃, PMN) was prepared by a molten salt synthesis method. Powder characteristics were greatly influenced by the processing parameters, such as amount of salt, species of salt, and the presence of excess PbO. Grown in sulfate salts, PMN crystallites showed faceted morphology with a bimodal particle-size distribution in which the smaller particles were in the submicrometer range. The presence of excess PbO in the sulfate salts greatly influenced the faceted morphology and resulted in rounded PMN crystallites. The possible origin of particle morphology changes due to the processing parameters is discussed.     

Effect of soy sauce type on the quality characteristics of emulsion sausages

The emulsion sausages were prepared with industrially brewed soy sauce at levels of 0, 1, 3, and 5%, and were additionally prepared with two further types of soy sauce (mixed and Korean traditional soy sauces) at a concentration of 1%. Soy sauce increased the satisfaction for flavor and saltiness of emulsion sausages. Addition of 1% soy sauce improved the overall acceptance without adverse effect on physicochemical and textural properties. From the results of electronic nose analysis, soy sauce results in an increased peak intensity of the emulsion sausages. In principal component analysis, clusters of emulsion sausages formulated with Korea traditional soy sauce and industrially brewed soy sauce were clearly distinct from the control (without soy sauce). Thus, our study suggested that addition of 1% soy sauce could be effective for improving the flavor of emulsion sausages, and the effects are highly dependent on the type of soy sauce used.     

Quality characteristics of reduced-fat frankfurters with pork fat replaced by sunflower seed oils and dietary fiber extracted from makgeolli lees

The effects of reducing pork fat levels from 30% to 20% by partially substituting pork fat with a mix of sunflower seed oil (0, 5, 10, 15, and 20%) and makgeolli lees fiber (2%) were investigated based on physicochemical properties, textural properties, and sensory characteristics of reduced-fat frankfurters. The moisture and ash content, and lightness were higher in reduced-fat frankfurter samples containing sunflower seed oil and makgeolli lees fiber than in the control. The results showed that reduced-fat frankfurter samples with higher sunflower seed oil levels had lower redness and yellowness values, as well as less cooking loss, emulsion stability, hardness, springiness, and apparent viscosity. The results of this study show that incorporating sunflower seed oil and makgeolli lees fiber into the formulation successfully reduced animal fat in frankfurters, while improving quality characteristics.