• Food Science of Animal Resources
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• v.33 no.6
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• pp.744-751
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• 2013

The objective of this study was to assess the physicochemical and sensory changes of a kefir manufactured by a two-step fermentation (MTY, $1^{st}$ step: $37^{\circ}C$ for 9 h; $2^{nd}$ step: $24^{\circ}C$ for 15 h) and compare it with kefirs produced by two conventional methods (GTY, fermentation at $37^{\circ}C$ for 24 h; KEY, $22^{\circ}C$ for 24 h). Rapid changes in pH and titratable acidity (TA) were observed in samples from all three manufacturing methods during fermentation process and storage period. Lactic acid bacteria (LAB) counts of MTY increased gradually up to 12 h of fermentation, reaching 9.28 Log CFU/mL, with maximum value observed in this experiment of 9.48 Log CFU/mL. The LAB counts of all samples decreased significantly during storage. The highest viscosity was observed for MTY (1750-1771 cPs), compared with the lowest viscosity observed for KEY (1250-1277 cPs). The viscosity of all samples increased slightly during storage (1250-1805 cPs, p<0.05), as well as carbon dioxide content (0.01-1.36%, p<0.05), except for GTY. The most significant increase in alcohol concentration during storage period was seen in MTY from 0.01% to 1.36% (p<0.05). MTY scored significantly higher in most items of the sensory analysis, indicating that the product manufactured by the two-step fermentation method is more acceptable compared with conventionally produced kefirs.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.865-872
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• 2017

The objective of this study was to determine the antioxidant and quality characteristics of yogurt added green olive powder stored at $4^{\circ}C$ for 15 d. The following four groups were used in this study: Control group (GY0), Yogurt added with 1% green olive (GY1), with 3% green olive (GY3), and with 5% green olive (GY5). The more time of titratable acidity went by, the more it increased. Except GY0, viscosity tended to decrease in other groups (p>0.05), and the more time of syneresis went by, the more it increased, but GY3 of them showed the lowest syneresis. Lactic acid bacteria showed no significant with GY0 until 5 d, but after that, GY1, GY3 and GY5 showed lower than GY0. Yogurt added green olive showed darker color than GY0 (low $L^*$ and high $a^*$). The antioxidant activity of GY5 was found to be the highest among the four groups at day 1 of storage. Total phenolic content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and reducing power of GY5 was found to be the highest among the four groups at day 1 of storage which were 6.96 mg GAE/kg, 47.53%, and 0.57, respectively. In the sensory evaluation sweet and overall of GY3 indicated the highest score among the four groups. Results of this study demonstrated that green olive powder might be used to improve the antioxidant capacity and sensory characteristics of yogurt.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.227-233
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• 2014

The discovery of bioactive compounds in foods has changed the dietary lifestyle of many people. Cyperus esculentus (tigernut) is highly underutilized in Africa, yet tigernut extract is highly profitable in Europe. This study aims to add value to tigernut extract by revealing its health benefits and food value. In this study, tigernut tubers were germinated or roasted and the extracts were combined with Moringa oleifera extract (MOE) or Hibiscus sabdariffa extract (HSE) and spiced with ginger to produce functional drinks. The drinks were evaluated for physicochemical characteristics, sensory parameters, and antioxidant potentials. The total phenolic content of each beverage was measured by the Folin-Ciocalteu method, and the antioxidant activity of each beverage was determined by the 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid assays. The beverages from the germinated tigernut extracts had the highest titratable acidity and the lowest pH, while beverages containing the roasted tigernut extract had the highest $^{\circ}Brix$. Germination and roasting significantly enhanced the total phenolic content of the drinks. The beverage containing HSE and germinated tigernut extract had a total phenolic content of 45.67 mg/100 mL gallic acid equivalents, which was significantly higher than the total phenolic content of all other samples. The DPPH inhibition activity of the beverages prepared with germinated tigernut extracts was significantly higher than the DPPH inhibition activity of the beverages prepared with fresh tigernut extract. The taste and overall acceptability of drinks containing the roasted tigernut extract were preferred, while the color and appearance of drinks with the germinated samples were preferred. Roasting or germinating tigernuts before extraction and addition of MOE or HSE extracts is another way to add value and enhance the utilization of tigernuts.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.113-120
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• 2004

Selected microbiological and biochemical characteristics of the steeping process for the production of yukwa, a traditional Korean oil-puffed snack made of waxy rice, were investigated during steeping of waxy rice in water for 15 days. The lengthy steeping process was largely predominated by lactic acid bacteria (LAB), particularly, Lactobacillus and Leuconostoc. The predominat type of bacterium isolated was the Y26 strain tentatively identified as Lactobacillus plantarum. The titratable acidity of the steeping medium increased from 0.01 to 1.13%, in parallel with the decrease in pH ranging from 6.3 to 4.2 as the steeping period increased from 0 to 15 days. A high amount of lactic acid and to a much lesser extent, butyric acid, acetic acid, propionic acid, and succinic acid were detected during the steeping process. The amount of reducing sugars in the steeping medium increased from 0.61 to 10.43 mg/mL, whereas sucrose decreased from 0.46 mg% to an undetectable level. Starch degradation products including glucose, maltose and oligosaccharides ranging G3-G7 were not initially noticed, but their content increased during the steeping process until completion. However, no oligosaccharides larger than G8 were detected in the steeping medium. The activities of $\alpha$-amylase, $\beta$-amylase and protease in the steeping medium of waxy rice tended to rise increase with time during the steeping process. From these results, the lengthy steeping process in yukwa production can be characterized as the spontaneous fermentation, dominated by lactic acid bacteria, which is a necessary process for inducing biochemical modification of waxy rice.

• The Korean Journal of Community Living Science
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• v.21 no.4
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• pp.641-649
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• 2010

To make sure of the usefulness of extract of Rubus coreanus Miquel for producing functional feeding honey, we compared some antioxidative indicators of feeding honey using extract of Rubus coreanus Miquel with acacia honey, SueBee Clover honey(USA), feeding honey on the market. The water content of four honeys were 16.6~26.5%, pH were 3.18~3.70, and titratable acidity ranged 0.018~0.022%. The phenolic compound contents of SueBee Clover honey and feeding honey using extract of Rubus coreanus Miquel were 8.3 mg/100 g and 7.3 mg/100 g, respectively, and were significaltly higher thgheacacia honey and feeding honey on the market. The flavonoid contents per 100 g of honey ranged from 2.3 mg(acacia honey) to 15.0 mg(SueBee Clover honey). DPPH anion scavenging activity of four honeys were not high. 0.5~2.0 g/ml of feeding honey using extract of Rubus coreanus Miquel was 16~36% and showed a concentration-reliant figure. At the concentration of 0.25~0.75 mg/ml, the reducing power of four honeys increased concentration-dependently, and the power of 0.25 mg/ml of feeding honey using extract of Rubus coreanus Miquel was corresponding to thgt of $150{\mu}g$/ml of a vitamin C solution. ABTS radical scavenging activity of feeding honey using extract of Rubus coreanus Miquel was 43.3~68.4%; the highest activity amongst all samples. When plotting the dose-response curve, ABTS radical scavenging activity also increased as their concentration increased from 62.5 mg/ml to 500 mg/ml. The heat treatment reduced the phenolic compound contents of acacia honey and feeding honey using extract of Rubus coreanus DPPH anion scavenging activity of feeding honey on the market and feeding honey using extract of Rubus coreanus Miquel did not changed significaltly after heating for 20 min, and the three honey except SueBee Clover honey maintained the reducing power with the same treatment.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.83-92
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• 2012

This study was performed for analyzing the general composition and the change in the quality of soymilk-derived yogurts manufactured by adding skim milk and whey powder to soymilk heat-treated at $95^{\circ}C$/5 min and $120^{\circ}C$/10 min, respectively. 1. During the storage of soymilk yogurt, the concentrations of total solids, protein, fat, and lactose slightly decreased, whereas viscosity, content of ash and NPN, and the number of lactic acid bacteria remained unchanged. 2. The pH and titratable acidity changed rapidly in all soymilk yogurts after 3 h of incubation. 3. We found $7.8{\times}10^8$ lactic acid bacteria in the control sample, $4.7{\times}10^8$ and $5.02{\times}10^8$ in soymilk yogurt with skim milk, respectively, and $5.9{\times}10^8$ and $5.5{\times}10^8$, respectively in soymilk yogurt with whey powder according to degree of heat treatment with $95^{\circ}C$/5 min and $120^{\circ}C$/10 min. 4. The viscosity of yogurt samples became lower as the heat treatment increased in temperature and in the length of time. 5. The value of sensory evaluation was relatively high in soymilk yogurt with the added skim milk, which was heat-treated $95^{\circ}C$/5 min; however, the value was significantly lower than that of the control sample. 6. Lactose, glucose, and galactose were detected in all samples because lactose is degraded into glucose and galactose within 3 h of inoculation.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.103-112
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• 2015

This study was conducted on how the harvest time affect fruit quality, core breakdown, and taste of GA-pasted 'Wonhwang' pear (Pyrus pyrifolia Nakai) fruit in order to verify the optimum harvest time. Harvest time included 110, 115, 120, 125, 130 days after full bloom (DAFB). Delayed fruit harvest increased fruit weight and content of soluble solids but decreased firmness, titratable acidity, and starch content. Harvest at 130 DAFB severely reduced fruit firmness and increased fruit core breakdown for 21 days at room storage, while harvest at 115 DAFB showed the opposite result of the fruit firmness and breakdown. Delayed fruit harvest reduced fruit taste, regardless of GA pasting on fruit. GA-pasted fruit showed reduced taste in advance compared to those of non GA-pasted fruit, regardless of the harvest time. Harvest at 120 DAFB would be suitable to maintain fruit quality and reduce core breakdown.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.387-391
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• 2017

Kiwifruits introduced to Korea typically have green fruit flesh, yellow flesh, or yellow flesh with red coloration around the core. Here, we describe a new cultivar called 'Redvita', the first kiwifruit cultivar of Korea with yellow flesh and red coloration around the core. A conventional field cross was conducted in 2003, and permission for the final release of 'Redvita' was obtained in 2012. 'Redvita' originates from 'Red Princess', a maternal vine known for the red coloration in its flesh. The pollinizer is 'NHK0013' (IT233175), which blooms in early May. A principal feature of 'Redvita' is its high vitamin C content, which at an average of 140 mg per 100 g of fresh weight is 2 - 4 times higher than other commercial cultivars. The average fruit weight is 97 g; bigger than that of the control cultivar 'Hongyang'. 'Redvita' blooms in mid-May and is usually harvested in early to mid-October, approximately 150 - 160 days after anthesis. 'Redvita' produces 3 or 4 flowers per fruiting shoot, with no small lateral flowers, therefore does not need to be thinned before blooming for commercial production. The cultivar is acidulous because of a high titratable acidity content (about 1.5%), which is higher than other cultivars (less than 1.0%). 'Redvita' was registered with the Korean Seed and Variety Service in 2015 for plant variety protection rights (no. 5604).

• Horticultural Science & Technology
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• v.35 no.3
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• pp.300-313
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• 2017

'Unicon' cherry tomato (Solanum lycopersicum) is one of the most highly perishable horticultural crops due to its high water content and respiration rate. This study was carried out to assess the effect of continuous application of $CO_2$ (control [air], 3%, and 5%) on the quality and shelf life of cherry tomato fruits stored at $10^{\circ}C$ and $85{\pm}5%$ relative humidity (RH) at two maturity stages (pink and red). Continuous application of $CO_2$ did not affect the soluble solids content (SSC) or titratable acidity (TA) of the fruit at either maturity stage during storage. However, there was a significant difference among treatments in terms of flesh firmness, cell wall thickness, pectin content, vitamin C content, skin color, lycopene content, weight loss, ethylene production rate, respiration rate, and acetaldehyde and ethanol production. Fruits treated with 5% $CO_2$ maintained their high quality with regards to vitamin C, skin color ($a^*$), lycopene content, weight loss, physiological parameters (ethylene production rate, respiration rate, and volatile compounds), flesh firmness, cell wall thickness, and pectin content at both maturity stages compared with 3% $CO_2$ treatment and the control. Continuous application of $CO_2$ (5%) reduced the ethylene production rate and the production of volatile compounds during storage. Therefore, cherry tomato 'Unicon' fruit can be stored for two weeks without losing fruit quality at both maturity stages under continuous application of 5% $CO_2$ as a postharvest treatment.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.293-297
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• 2005

This experiment was carried to investigate the optimum concentration of abscisic acid (ABA) treatment for enhancing fruit coloration of 'Kyoho' grapes. Cluster and berry weights showed a tendency that increased in proportion to concentration of ABA treatment, but were not significant in all treatments. Also, soluble solids and titratable acidity were not significant during fruit development in all treatments. L-phenylalanine ammonia-lyase (PAL) activity showed a tendency that decreased after rapidly increased in all treatments, and was the highest in 1000 mg/l ABA treatment at final harvest. Anthocyanin and total phenolics contents were high in proportion to ABA treatment concentration, and anthocyanin content in 1000 mg/l ABA treatment was 2.5 folds of that in control. Fructose and glucose as soluble sugars were detected, but sucrose was not detected. Both fructose and glucose contents increased during fruit development, but showed little difference in all treatments.