• Animal Bioscience
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• v.36 no.7
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• pp.1101-1119
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• 2023

Objective: This study aimed to evaluate the physicochemical, metabolomic, and sensory qualities of Chikso and Hanwoo beef during 28 days of wet aging. Methods: Rump and loins from Hanwoo and Chikso were obtained and wet-aged for 28 days at 4℃. The samples were collected at 7-day interval (n = 3 for each period). Physicochemical qualities including pH, meat color, shear force value, and myofibrillar fragmentation index, metabolomic profiles, and sensory attributes (volatile organic compounds and relative taste intensities) were measured. Results: Chikso showed a significantly higher shear force value than Hanwoo on day 0; however, no differences between breeds were found after day 14, regardless of the cuts. Overall, Chikso had more abundant metabolites than Hanwoo, especially L-carnitine and tyrosine. Among the volatiles, the ketone ratio was higher in the Chikso rump than the Hanwoo rump; however, Chikso had fewer alcohols and aldehydes than Hanwoo. Chikso rump showed higher taste intensities than the Hanwoo rump on day 0, and sourness decreased in Chikso, but increased in the Hanwoo rump on day 14. Wet aging for 14 days intensified the taste of Chikso loin but reduced the umami intensity of Hanwoo loin. Conclusion: Chikso had different metabolomic and sensory characteristics compared to Hanwoo cattle, and 14 days of wet aging could improve its tenderness and flavor traits.

• Animal Bioscience
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• v.37 no.5
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• pp.908-917
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• 2024

Objective: Although pork loins is not a tough meat, they need to develop meat products with a soft texture for the elderly. This study focused on the physicochemical properties and tenderness characteristics of pork loin injected with green kiwifruit juice (GRJ) and gold kiwifruit juice (GOJ) during various incubation times. In addition, the antioxidant activities of hydrolysate derived from the hydrolysis of pork loin by kiwifruit juice protease were evaluated. Methods: The pork loin was injected with 10% and 20% GRJ and GOJ, under various incubation times (0, 4, 8, and 24 h). Then, the physicochemical properties and tenderness of pork loins were measured. 2,2- diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power were conducted to determine hydrolysate's antioxidant activities derived from pork loin's hydrolysis by kiwifruit juice protease. Results: GRJ had greater tenderizing ability than GOJ, even at the 10% addition. When kiwifruit juice was injected into pork loin, the tenderness increased with increasing incubation time. This was confirmed by the decrease in intensity of the myosin heavy chain (MHC) band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In particular, the MHC band decreased at 8 h for both 10% GRJ and 20% GOJ and at 4 h for 20% GRJ alone. The highest myofibril fragmentation index and peptide solubility were observed in pork loin treated with 20% GRJ compared to the other treatments during incubation. The 10% GRJ and 20% GOJ treatments showed similar levels of antioxidant activity of the protein hydrolysates in pork loin, and 20% GRJ showed the highest activity among the treatments. Conclusion: Kiwifruit juice had protease activity, and GRJ was more useful for tenderizing meat products than GOJ. Thus, GRJ at 10% could be a potential agent to tenderize and enrich the natural antioxidant activity through the proteolysis of pork loin.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.260-265
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• 2000

To determine the quality change of the irradiated eggs during storage, fresh shell eggs were irradiated using $^{60}Co$ at 0, 1, 5, 10, 30 kGy and stored for 30 days. The york index, color, pH, viscosity, egg weight, and SDS-PAGE profile of the irradiated eggs were examined. During storage, york index values of the irradiated eggs and the control were decreased and the increase of dose decreased yolk index. However, the yolk index values were increased temporarily at 10 kGy and 30 kGy. The yolk color had a bright yellow with increases in dose level and there was no significant change during storage. The albumen viscosities were decreased with increases in dosage and were decreased during storage. Also, the albumen pH values of the irradiated eggs were higher than that of the control and were increased during storage. The weight losses of eggs were increased during storage and there were no significant changes by dose level. SDS-PAGE profile of the egg white proteins of the shell eggs showed the change in molecular weight distribution and had aggregation pattern as well as degradation. CD and fluorescence spectroscopy study showed changes in the secondary and tertiary structure of egg white proteins by ${\gamma}-irradiation$. Therefore, this study clearly indicates that irradiation dose of eggs should be appropriate to prevent the loss of egg qualities.

• Food Engineering Progress
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• v.14 no.2
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• pp.127-134
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• 2010

This study was to develop high-nutritious energy bar from extruded hemp obtained by extrusion process. Mixture of rice flour and defatted hemp was extruded at a barrel temperature of 110 and 130$^{\circ}C$, and moisture content of 20 and 25%. Properties of extrudates such as bulk density, expansion index, breaking strength, apparent elastic modulus, water absorption index (WAI), water solubility index (WSI) have been analyzed. The antioxidant potential was determined by the DPPH-radical scavenging assay. The expansion index was the highest in rice-hemp extrudate at 130$^{\circ}C$ barrel temperature and 20% moisture content among the other hemp-added extrudates. The WAI was increased with increase in moisture content, while the WSI was increased with increase in barrel temperature. The peak viscosity of rice extrudate had higher valule than those of extrudate added with hemp. DPPH scavenging activity of rice-hemp extrudate at 130$^{\circ}C$ barrel temperature and 20% moisture content showed the highest value. Sensory properties, moisture content and color were assessed for quality of energy bar. The color values of the energy bar indicated decreasing L (lightness) and b (yellowness), and increasing a (redness) after 30 days storage at ambient condition. The highest overall acceptable was the energy bar added with rice-hemp extrudate at 130$^{\circ}C$ barrel temperature and 20% moisture content.

• Food Science and Preservation
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• v.30 no.2
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• pp.311-320
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• 2023

Surfactin, one of the most powerful biosurfactants, can be widely applied in agriculture, food, and pharmaceutics. The purpose of the present study was to establish suitable indicators for a rapid detection method that can confirm the surfactin productivity of cheonggukjang. In the present study, changes in the total number of bacteria were quantified according to the fermentation time of chenggukjang. Furthermore, physicochemical factors, such as pH, color value, surface tension, refractive index, absorbance, and protein contents, were assessed in chenggukjang viscous substances, and a correlation analysis between the physicochemical factors and surfactin contents was performed. We found that the protein contents gradually increased up to 48 h (4.21±0.11 mg/mL) without a change in the surface tension. Furthermore, the refractive index, absorbance at 280 nm, and color value were significantly increased as the fermentation time increased; however, there were no statistically significant differences after 36 h of fermentation. Interestingly, this result exhibited a tendency similar to the surfactin content according to fermentation time. These findings suggest that surfactin can be used as a suitable quality indicator and may provide an experimental basis for the fermented food industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1797-1801
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• 2011

Two brown rice samples differing in amylose content, 20.1 (normal) and 7.3% (low amylose) were milled by different milling methods, and their physicochemical properties were tested. Particle size of brown rice flour prepared by dry milling using a pin mill (DM) was lower than that prepared by wet milling using a roll mill (WM). Particle size was further reduced by successive dry milling of the flour after wet milling and drying (WM/DM). Damaged starch contents in the wet milled brown rice flour were 14.6 and 15.6% for the normal and low amylose samples, respectively, whereas they were only 4.2 and 4.8% for the dry milled samples. WM/DM method resulted in a lower damaged starch (%) than DM, despite a reduced flour particle size. Water absorption index (WAI) of the brown rice flour was the lowest after WM/DM, and the water solubility index (WAI) was higher in the order of DM, WM/DM, and WM. Brown rice flour with normal amylose content appeared to have significantly higher pasting viscosities, as determined using a Rapid Visco Analyzer (RVA). Compared to dry milled brown rice flour, wet milled brown rice flour showed lower peak viscosity and higher final viscosity, resulting in increased setback value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.688-694
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• 2017

The effects of heat treatments on the physicochemical properties and in vitro biological activities of quinoa (Chenopodium quinoa Willd.) were investigated. Quinoa grains were subjected to two different heat treatment methods: boiling and steaming plus roasting (steaming/roasting). Compared with raw quinoa, boiled quinoa samples had slightly lower crude protein, crude fat, crude ash, and starch contents. However, steaming/roasting treatment did not cause significant differences in proximate composition. Heat treatments reduced total phenolic and flavonoid contents in quinoa extracts, and higher reduction was detected upon boiling treatment. Heat treatments also reduced lightness and increased yellowness of quinoa samples. Heat treatments increased water absorption index but decreased water solubility index. In vitro starch hydrolysis increased substantially after both heat treatments, and slightly higher values were observed in the boiled quinoa samples. 1,1-Diphenyl-2-picrylhydrazyl free radical scavenging activity and nitrite scavenging activity were reduced by heat treatments, and the boiled quinoa sample showed the lowest activity likely due to loss of activities in cooking water.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.171-175
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• 1999

Changes in physicochemical characteristics of steamed rice during roasting were investigated. Steamed rice was roasted at various temperature $(150{\sim}220^{\circ}C)$ for various time $(10{\sim}30min)$. L and b Hunter color values of steamed rice were decreased, but E value was increased by roasting. The water absorption index and the water solubility index were gradually with increasing roasting temperature and time up to $200^{\circ}C$ for 30min, but decreased at $220^{\circ}C$ for 20min. The yield of water extracts from steamed and roasted rice were sharply increased with increasing roasting temperature and time, however, precipitates and turbidity were decreased. The content of reducing sugar was slowly increased up to $200^{\circ}C$ and remarkably increased above it. The contents of amino acids were decreased by roasting. Among them, cystine, lysine and serin were significantly reduced with increasing roasting temperature.

• Food Science and Preservation
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• v.22 no.4
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• pp.591-597
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• 2015

In this study, extracts of chlorella using different extraction methods were compared for antioxidant activities and spray-dried chlorella powders were investigated for their physicochemical characteristics. The DPPH radical scavenging activity and superoxide radical scavenging activity of 50% ethanol extract were 29.19%, and 48.91%, respectively. The oxygen radical absorbance capacity (ORAC) of the 50% ethanol extract ($150.44{\mu}M/g$) was higher than those of other extracts. The total chlorophyll content of the 50% ethanol extract (542.89 mg/100 g) was higher than those of other extracts. The microencapsulation of the 50% ethanol extract was manufactured by spray-drying with 10 % maltodextrin (SD-C10), 20% maltodextrin (SD-C20), and 30% maltodextrin (SD-C30). The particle size of the freeze-dried powder ($454.47{\mu}m$) was higher than those of the spray-dried powders ($24.15{\sim}32.49{\mu}m$). Scanning electron microscope images showed that the spray-dried chlorella powders using SD-C10, SD-C20, and SD-C30 had an uniform particle distribution. The water absorption index and water solubility index (WSI) of powders were 0.31~0.45, and 96.96~98.28%, respectively. The spray-dried powders showed the stability in total chlorophyll content for 40 days storage. Based on these results, spray-dried chlorella powders could be used in various types of food processes.

• Journal of Mushroom
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• v.18 no.3
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• pp.268-273
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• 2020

This study aimed to assess the feasibility of composting spent mushroom substrate (SMS) materials of Lentinula edodes (Le), Hericium erinaceus (He), and Pleurotus ostreatus (Po). The different SMSs were composted for 7 to 10 days at high temperatures over 50℃; the composting procedure was completed in 30 days. A maturity test was conducted using the radish seed germination index and CoMMe-100. The composted SMS (CSMS) from Le and He showed gemination indices of 130% and 81%, respectively, that satisfied the criteria of maturity standard (gemination index over 70%) and the CoMMe-100 analysis. The physicochemical changes of CSMSs included an increase in the pH range from 4-5 to 6-7, slight reduction in the EC to 1-1.4 dS/m, and an organic content of 36.9% in LeCSMS. In LeCSMS, the contents of N, P, and K were 1.2%, 2.3%, and 0.77%, respectively, and heavy metals were detected below the standard value in all CSMSs; the Ca and Mg contents in the CSMSs were increased from 30% to 60% when compared to those in the SMSs. The C/N ratio (from 26-33) in LeSMS and HeSMS decreased to 15.3-15.9 in CSMSs. The growth effect of LeCSMS treatment on pepper seedlings was 60% higher than that in the control groups, one of which was treated with commercial organic compost; the former showed a superior growth effect on the leaf width, leaf length, and leaf number compared to other control groups. In conclusion, LeCSMS and HeCSMS could be utilized as compost resources capable of efficient soil amendment and plant growth promotion.