The aim of this study was to determine the effects of different soy protein concentrate (0, 15, 30, and 45%), defatted soy flour (0, 10, 20, and 30%), and wheat flour (10, 20, and 30%) contents replacing fish meal on physiochemical properties of extruded aquatic feed by using a twin screw extruder. The moisture content, barrel temperature, die diameter, and screw speed were adjusted to 45%, 137oC, 4 mm, and 250 rpm, respectively. With the higher amount of soy protein concentrate replacing fish meal, the expansion ratio, swelling ratio, and water stability increased significantly while specific length and water holding capacity decreased significantly. With the increasing defatted soy flour content, expansion ratio increased significantly, but specific length, water holding capacity and water stability decreased significantly. With increase in the wheat flour content, the specific length significantly decreased while the water stability significantly increased. In conclusion, aquatic feed quality was optimized in this study and could be used in the future.
The impregnation of solid foods into the surrounding hypotonic or hypertonic solution was explored as a method to infuse NaCl in pork loin cube without altering its matrix. Mass transfer kinetics using a diffusive model as the mathematical model for moisture gain/loss and salt gain and the resulting textural properties were studied for the surrounding solutions of NaCl 2.5, 5.0, 10.0 and 15% (w/w). It was possible to access the effects of brine concentration on the direction of the resulting water flow, quantify water and salt transfer, and confirm tenderization effect by salt infusion. For brine concentrations up to 10% it was verified that meat samples gained water, while for processes with 15% concentration, pork loin cubes lost water. The effective diffusion coefficients of salt ranged from 2.43×10-9 to 3.53×10-9 m2/s, while for the values of water ranged from 1.22×10-9 to 1.88×10-9 m2/s. The diffusive model was able to represent well salt gain rates using a single parameter, i.e. an effective diffusion coefficient of salt through the meat. However, it was not possible to find a characteristic effective diffusion coefficient for water transfer. Within the range of experimental conditions studied, salt-impregnated samples by 5% (w/w) brine were shown with minimum hardness, chewiness and shear force.
In this study, the nutritional components (moisture, fat, protein, ash) value of military hardtack was collected and analyzed to control the mixing ratio of rice and flour. Hardtack from 4 factories was analyzed by 3 testing organizations certified by the Korean Ministry Food and Drug Safety. In addition, the accuracy and collaborative study possibility of each organization were evaluated in Q-test and HorRat. Also, other hardtack groups with different mixing ratios were compared to quality control of hardtack by I-MR charts. As a result, the HorRat and Q-test values of test organizations were 0.5-6.2 and 0.08-0.91, respectively. The quality of hardtack by the factories was similar. However, for accurate management of the mixing ratio, suggesting both upper and lower limit requirements of the nutritional components is necessary.
This study was carried out using Celluclast 1.5L to increase the content of 2,6-DMBQ and water extractable arabinoxylan in wheat germ extract. Extraction temperatures were 30oC, 45oC and 60oC. The extraction times were 0, 6, 12, 18, 24 and 30 h. The pH of the extract decreased rapidly from 18 h at 30oC in both water- and enzyme-treated extracts. 2,6-DMBQ of water- and enzyme-treated extracts increased with the extraction time. At 30-hour extraction time, enzyme-treated extract increased 27.60% at 30oC extraction temperature than water extraction. Extraction temperatures of 45oC and 60oC were increased by 65.03% and 151.05%, respectively. The highest content of waterextractable arabinoxylan was 15.23±0.08 mg/g when the enzyme was treated at an extraction temperature of 60oC for 30 h. At 30=hour extraction time, enzyme-treated extract increased 7.92% at 30oC extraction temperature compared to water extraction. Extraction temperatures of 45oC and 60oC were increased by 31.20% and 54.38%, respectively.
To investigate the effects of tagatose added to yogurt fermented with Streptococcus thermophiles (ST) or Lactobacillus delbrueckii subsp. Bulgaricus (LB), pH, titratable acidity (TA), sugar content, color value, viable cell number, and sensory evaluation were determined on yogurts added with 7% sucrose, tagatose, or a mixture of sucrose and tagatose in triplicate. After 24 h, pH and sugar content of sucrose-added yogurt reached nearly 4.5 and 4.2 respectively, and were lower than those of yogurt with tagatose (above 5.6 and 8.6, respectively). Also, TA of sucroseadded yogurt (1.51%) was much higher than that of yogurt with tagatose (0.59%). There were no significant differences in color value and viable cell count after 24 h. However, the addition of tagatose seems to slow the growth rate of LB more than that of ST. Sensory preference revealed that mixture-added yogurts scored significantly higher in taste (5.90), texture (5.86), and overall acceptability (6.16) than yogurts with tagatose (5.20, 5.02, and 5.36, respectively), but there was no significant difference from the sucrose-added yogurts. In conclusion, tagatose inhibited the fermentation rate, but the mixture of tagatose and sucrose could be used for yogurts with lower calories and glucose index (GI) without a sensory difference from sucrose-added yogurt.
The aim of this study is to investigate the relationship between the sensory characteristics and protein concentration of enzymatically hydrolyzed isolated soy protein. As a result of QDA, 34 attribute descriptors were developed. According to the results of the flavor profile, the strengths of most color and tastes except sourness were evaluated before activated carbon treatment sample. Principal component analysis (PCA) was performed to summarize the relationship between attributes and samples. The result of PCA was 56.35% (F1) and 35.05% (F2), having explained 94.13% in total variablility. In case of the untreated sample of active carbon, it was located in the first quadrant and correlated with color, flavor, a slightly salty taste, and a slightly bitter taste. It also showed high correlation with meju taste. The activated carbon treatment samples were located in the second quadrant and correlated with delicate taste, slight saltiness, sourness, and umami, having high correlation with burned rice.
β-mannanase from Trichoderma reesei was purified by DEAE Sephadex A-50 ion exchange chromatography and Sephadex G-100 gel chromatography. The molecular weight was determined to be 54 kDa by tricine SDS-PAGE. Trigonella foenum-graecum galactomannan was hydrolyzed by the purified β-mannanase, and then the hydrolysates were separated by Bio-Gel P2 chromatography. The main hydrolysates were composed of D.P. (degree of polymerization) 2, 3, and 4, 6 galactomanno-oligosaccharides. To investigate the effects of Trigonella foenum-graecum galactomanno- oligosaccharides on in vitro growth of L. plantarum, were cultivated individually on a modified-MRS medium containing carbon sources such as low- and high-molecular-weight galactomanno-oligosaccharide. Lactobacillus plantarum grew 1.8-fold after treatment with high- and low-molecular-weight galactomanno-oligosaccharides, compared to 1.3-fold for those with standard MRS medium. Bacteriocin was purified by Sephadex G-100 gel chromatography and determined to be 122 kDa by tricine SDS-PAGE. The bacteriocin activated doubly more effectively after treatment with galactosmanno-oligosaccharides compared to those with standard MRS medium. Bacteriocin showed antimicrobial activity against Staphylococcus aureus. The inhibitory compound lost activity when heated to temperatures greater than 30oC and when inhibited to pH changes that lowered the pH below 4 or raised it above 5. Furthermore, its effects were inhibited by treatment with proteolytic enzymes.
For the vessel export of strawberries, modified atmosphere package (MAP) using polyamide (PA) film and linear low density polyethylene (LLDPE) film was investigated to extend the shelf life of strawberries. Because the temperature and relative humidity changes of the MAP were lower than the changes of the control, the weight loss of the MAP were lower than that of the control. The low oxygen level and high carbon dioxide level were effective to decrease the fungal decay rate and to increase the hardness of strawberries. The Hunter’s color differences before and after storage showed no distinct difference between the MAP and the control. The lightness had a tendency to decrease while the redness increased. There were no significant changes of the soluble solids during the storage. The shelf life of strawberries could be extended to 16 days using the MAP considering the weight loss and the fungal decay rate. Thus, this MAP method using PA film and LLDPE film was effective to extend the shelf life of strawberries.
In this study, the physical and sensorial properties of the meat analog were studied for the purpose of improving sensory preference and mimicking animal meat. The meat analog was made with different types of liquid materials such as oil, water, lecithin, polysorbate 80, or the emulsion of these components. At the aspect of density, the sample mixed with oil was higher than the sample mixed with water. Cooking loss value was higher at the sample with water than the sample with oil and this was the result opposite to the liquid holding capacity analysis. Also, texture profile analysis result showed that the samples with medium chain triglycerides (MCT) oil only showed the highest values in all attributes except for adhesiveness. Principal component analysis was carried out to analyze sensorial properties and it showed that the overall acceptance was high when the juiciness and softness increased. This result was highly related with the addition of emulsion. Therefore, emulsion technology can be a good candidate for improving the quality of meat analog and for mimicking the taste of animal meat.
This study investigated the effects of blanching conditions on the quality characteristics of burdock, lotus root, and garlic scape. The selected plants were blanched at varying temperatures (70-100oC) for 1-5 min, and moisture content, shear force, color, and total microbial count were analyzed. Burdock exhibited browning discoloration when it was blanched at a relatively low temperature (70-80oC). In addition, thermal tenderization of burdock was not evident in the blanching conditions adopted in this study. Blanching affected the tenderness and moisture content of lotus root without deteriorative discoloration. In particular, low temperature blanching (80oC) was favorable to blanching lotus root. Alternately, thermal tenderization of garlic scape was possible by blanching at 80- 100oC for 3-5 min, while discoloration of the blanched garlic scape dominated at high-temperature blanching (100oC). Consequently, the result indicated that low temperature for a long time (80oC and 3-5 min) provided a better blanching condition for lotus root and garlic scape than high temperature applied at a short time (100oC and 1-3 min).