Proteolytic enzymes were screened to obtain anchovy protein hydrolysates (APH) with low-bitterness under pressurization. First, the residual proteolytic activity (%) and SDS-PAGE of commercially available food-grade protease (Alcalase® 2.4 L, FlavourzymeTM 500 MG, Neutrase®, ProtamexTM) and mixed enzyme (ME, Alcalase® : FlavourzymeTM = 1 : 5) after treatments of ambient pressure and 100 MPa at 50oC were investigated. The proteolytic activity of enzymes was still largely retained after pressure treatment. The SDS-PAGE on tested enzymes showed that the electrophoretic mobility maps (EMMs) after pressure treatment were similar to those at ambient pressure. With these results, it seemed that tested enzymes were stable at 100 MPa and 50oC. Raw anchovy hydrolyzed with various protease at 50oC under ambient pressure and 100 MPa for 1, 2, 6, 12, and 24 h. The degree of hydrolysis (DH, %) of prepared APHs at 100 MPa was increased, which suggests that the medium pressure treatment accelerates protein hydrolysis. The APH by ME exhibited the best suitable characteristics, which had a relatively higher DH (36.2±1.8- 57.5±2.8), a high content of oligopeptides with a molecular mass lower than 1,100 Da, mildly bitter taste as the bitterness value was lower than that of 0.2 g/L tea alkaloid, and the lowest contents of tryptophan. Thus, ME was selected to obtain APH with low-bitterness under pressurization.
This study was carried out to investigate the effect of liposome-coated salt (LCS) on the salty taste intensity of noodle. Dough, dried noodle, and boiled noodle with LCS were evaluated physico-chemically for water content, water binding capacity, solubility, swelling power, color, texture, cooking properties, and sensory test. There were no significant differences in water content, water binding capacity, lightness, yellowness, and texture of noodle between the noodles with liposome-coated salt and non-coated salt. For the sensory analysis, the panel did detect more salty taste at 1.0% and 2.0% of LCS compared to the control. From these results, this study demonstrates that liposome coated salt can enhance salty taste, maintaining the same salt concentration without the physical property changes of noodle.
Taro is an alkaline food containing a lot of protein, vitamin C, and minerals. Matang is a food prepared by frying a starch-containing material in oil and glazing with honey or starch syrup and it is widely enjoyed as simple snack or dessert in Asian countries including Korea. In this study, to increase the usability of taro having high nutritional values, taro matang was prepared by varying the types of starch while the physical and sensory properties were investigated. The taro matang was prepared by mixing corn starch, sweet potato starch, potato starch, and sticky rice starch with taro. The chromaticity of taro matang samples were measured, and the results showed that the corn starch taro matang was the brightest (L=40.48±1.17) and the potato starch matang was the darkest (L=33.81±1.33). The pH of the taro matang samples were within the range of 6.16-6.26 with no significant difference. The physical properties of the prepared taro matang samples were measured. The hardness and fracturability of the sweet potato starch taro matang were the highest at 3,414.79 and 1,570.03, respectively. The springiness and chewiness of the corn starch taro matang were the highest at 0.95 and 1,773.24, respectively. With regard to sensory properties and preference, the taro matang samples having lower hardness and brighter chromaticity were preferred. The preference for the flavor, crispness, softness, taste, and overall preference of the potato starch taro matang were the highest. Therefore, taro matang prepared as snack or dessert by mixing with potato starch may satisfy consumers’ demand.
Food freezing preservation is an important process due to its high quality and long shelf-life. In order to improve the quality of frozen sweet potato stem, the freezing rate, thawing, and packaging method was optimized by the determination of physical properties. There was no significant difference among the treatment of freezing rate. Further, the drip loss of sweet potato stem was higher at a relatively fast freezing rate (immersion freezing) than at slow freezing rate (natural convection freezing at -20 or -40oC). For the comparison of packaging methods, the aircontaining packaged sweet potato stem had the lowest significant differences from the result of color, pH, and hardness. From the result of the drip loss, the high frequency and microwave using thawing samples were more effective than room temperature and water thawing. Therefore, fast freezing and thawing rate with air-containing package were recommended to obtain the better quality of sweet potato stem.
High pressure and enzymatic hydrolysis was applied to anchovy in order to produce a natural seasoning salt enhancer. The purpose of this study is to investigate the relationship between the sensory characteristics and protein concentration of enzymatic hydrolysates with anchovy. According to the results of QDA, 24 attribute descriptors were developed. Based on the flavor profile, the strengths of most tastes, except sourness, color flavor, and odor were evaluated before activated carbon treatment. Principal components analysis (PCA) was performed to summarize the relationship between attributes and samples. The result of PCA was F1 72.13% and F2 22.01%, having explained 94.13% in total variability, as F1 was shown according to the correlation about activated carbon treatment before or after samples. The characteristics of color, flavor/odor, and saltiness or bitter taste had higher correlation before activated carbon treatment samples. Also, F2 was shown to have no correlation to the samples.
The effects of drying temperature on the drying characteristics of soybeans at the different position in the dryer with 28.1% (±0.8) of initial moisture content were studied. Drying temperatures varied at 35, 45 and 55ºC, with a constant inlet air velocity (3 m/s). The local air velocities at a position 1, 5, and 9 were 0.150 m/s (±0.012), 0.247 m/ s (±0.018) and 0.795 m/s (±0.036), respectively. The drying rate increased as the local air velocity increased from 0.150 m/s to 0.795 m/s. The cracked grain ratio increased as the drying rate increased. To prevent quality degradation of soybeans during hot-air drying, the local air velocity should be considered. Thin-layer drying models were applied to describe the drying process of soybeans. The Midilli-Kucuk model showed the best fit (R2>0.99). Based on the model parameters, the drying time to achieve the target moisture content (15%) was successfully estimated. The drying time was strongly dependent on the position in the dryer and the drying temperature.
In the food industry, freezing storage has been an important process for maintaining the properties of food materials. In order to maintain the quality of blanched Colocasia esculenta (L.), Schott stem, packaging, freezing, and thawing methods were optimized by determinations of the physicochemical properties. For the comparison of packaging method, Colocasia esculenta (L.) Schott stem packed by air containment had the lowest significant differences of properties such as hardness and drip loss compared to the control samples. Overall, the drip loss of Colocasia esculenta (L.) Schott stem had lower value at fast freezing rate (immersion freezing). Considering the result of the drip loss, high frequency thawing was more effective than other thawing methods. Therefore, it was supposed that samples treated by air-containing packaging, immersion freezing, and high frequency thawing used the optimal method to maintain the original quality of Colocasia esculenta (L.) Schott stem.
Sea cucumber (SC) or Stichopus japonicas is widely used in East Asia as a traditional medical component for the treatment of asthma, arthritis, and sinus congestion. The hydrolysate of SC (HSC) after treatment with a protease is also widely used as an ingredient for processed food application such as noodles. Tensile force and deformation are important texture properties of noodle. The peptides prepared by hydrolyzing SC could affect the tensile properties of noodle, as well as DPPH radical scavenging. The objectives of this study were to characterize the tensile properties, the texture properties, color, and DPPH radical scavenging of noodle with HSC and to determine an optimum formulation of dough with HSC for noodle. The HSC was prepared by hydrolyzing dried SC powder with distilled water (DW) and a protease, Protamex (Novozyme Nordisk, Bagsvaerd, Danmark). The tensile properties and antioxidant activity were used as major constraint functions for the optimization. The optimum ratio was determined as flour:water:HSC=69.27:22.48:7.05 (w/w). Increasing the amount of HSC in the formulation increased the tensile force but no significant difference was observed in the deformation.
The aim of this study was to investigate the method validation for the determination of loganin content in Cornus officinalis (CO). This medicinal plant reportedly mainly included loganin. The specificity, linearity, precision, accuracy, limit of detection (LOD), and quantification (LOQ) were measured by HPLC/DAD. Our results showed that high linearity in the coefficient of calibration correlation (R2) for loganin standard was 1. LOD and LOQ for loganin were 0.007 and 0.026 mg/mL, respectively. The recovery rate of loganin was revealed to be in the high range of 95.14-105.45%. The relative standard deviation of intra- and inter-day precision of loganin in CO was 1.8% and 2.3%, respectively. The loganin content of CO from Gurye, Uiseng, Ichoen, and China were 7.81, 3.41, 7.42, and 6.52 mg/g, respectively. In conclusion, these methods were validated for the detection of loganin in CO.
The purpose of this study was to formulate the optimal ratio of tofu ice cream made with crushed tofu and soybean milk. Also, to compare characteristics of tofu ice cream and soybean ice cream. Mix viscosity, overrun and melting down are measured as characteristics of ice cream. The optimal mixing ratio of tofu ice cream was determined by response surface methodology based on overall quality. As a result of optimization, tofu ice cream was made with 65.90% tofu cream (9% solid contents), 4.35% whipping cream, 14.35% canola oil, 15.00% sugar, 0.2% emulsifier and 0.2% guar gum. Soybean ice cream made with three different treated (blanched, steamed, roasted) soybean and each preprocess are treated for 0-20 min. Mix viscosity was enhanced preprocessing time increasing. Also, overrun and melting down was decline preprocessing time increased. As a result of comparison of ice cream overall quality, 15 min roasted soybean ice cream was shown the best quality.
The effect of roasting intensity and extraction time of coffee bean on the antioxidant activity of roasted ground coffee extract was investigated. Coffee was roasted at 185oC using a rotating fluidized bed roaster for 5.17 (medium roasting) and 6.00 (dark roasting) min, respectively. Both roasted coffees were extracted in 90oC hot water according to the increased extraction time. Until 20 min, an increase in extraction time significantly increased soluble solute, caffeine, brown color, and phenolic compound. The soluble solid and caffeine contents showed no significant difference among medium- and dark-roasted coffee extracts. The brown color intensity and free radical scavenging activity of dark-roasted coffee extract were higher than those of medium-roasted coffee. On the contrary, the total phenolic content of dark-roasted coffee extract was lower than that of medium-roasted coffee. The free radical scavenging activity of coffee extracts showed a positive correlation with brown color intensity, as well as total phenolic content.