• Korean Journal of Food Science and Technology
• /
• v.40 no.2
• /
• pp.178-183
• /
• 2008

This study investigated the effects of osmotic dehydration (OD) and vacuum impregnation (VI) on the quality of dried apple products. Weight reduction and water loss increased during OD, but these decreased in the apples during VI. In particular, VI's effect on increasing solid gain was superb. For apples in 40% sucrose solution, OD and VI were followed by hot-air drying at 50$^{\circ}C$. The experimental data were fitted successfully using the modified Page model. OD and VI increased drying time and decreased the drying rate constant of these apples as compared to the control. Shrinkage and rehydration capacity greatly decreased in the apples dried by OD and increased in the apples dried by VI as compared to the control. OD also decreased titratable acidity and ascorbic acid content considerably. Sensory evaluations of the products indicated that the apples prepared by OD had higher palatability in their rehydrated form in yoghurt, and the apple products prepared by VI had higher palatability in their dried form.

• Korean Journal of Food Science and Technology
• /
• v.46 no.3
• /
• pp.341-346
• /
• 2014

This study was conducted to evaluate the effect of trehalose on the rheological properties of bread flour dough. Farinographic and viscographic properties, pH, total titratable acidity (TTA), and fermentation power were analyzed for flour dough rheology. Flour dough containing trehalose showed greater water absorption capacity and longer development time. However the stability, degree of softening, and farinograph quality number (FQN) were lower for the trehalose-containing flour dough, however, these factors decreased with increasing amounts of trehalose. Trehalose did not affect the beginning of gelatinization temperature and maximum viscosity temperature of flour. The maximum viscosity was the lowest with 6% trehalose, the end of final holding period, breakdown and setback values decreased with increasing amounts of trehalose. Flour dough with 4% trehalose had the lowest pH value for 120 min fermentation at $30^{\circ}C$, and the highest TTA value. Addition of 4% and 6% trehalose showed larger fermentation volume of dough than the control. The results suggested that trehalose positively affected the rheological properties of flour dough such as bread volume, softness, and staling delay.

• Korean Journal of Food Science and Technology
• /
• v.50 no.3
• /
• pp.297-307
• /
• 2018

The aim of this study was to develop a seasoning paste fermented by Aspergillus oryzae and Bacillus subtilis using three edible insects: Tenebrio molitor larvae, Gryllus bimaculatus, and Bombyx mori pupa. No significant changes in pH and titratable acidity were observed between the insect pastes and soybean control during a 5-week fermentation process. The amino nitrogen was 0.35-0.50% (w/w) in the early stage of the fermentation and increased to 0.72-0.78%. The total nitrogen was 2.36-3.62% (w/w) in the early stage and was preserved during the fermentation period. Free amino acids of the insect pastes were similar to those in soybean paste. In general, the fermented insect pastes showed a lower flavor and color than soybean paste but B. mori pupa-fermented paste did not show any significant difference in preference from soybean. Glutamate, aspartate, lysine, phenylalanine, arginine, and serine were found to affect taste preference. It was possible to ferment edible insect protein to produce a fermented seasoning paste like Korean doenjang.

• Korean Journal of Food Science and Technology
• /
• v.52 no.2
• /
• pp.113-118
• /
• 2020

We investigated the quality characteristics and antioxidant capacities of Korean commercial yogurt. Twenty commercial yogurt samples exhibited a pH of 4.05-4.51, titratable acidity of 0.80-1.45%, viable counts of 6.65-9.39 log CFU/g, and total phenolic content of 0.71-2.92 mg gallic acid equivalent/g dry weight (dw). Lactic acid was the major organic acid detected by HPLC with UV detection, and its content was 5.4 times and 46.5 times higher than that of malic acid and citric acid, respectively. The tested commercial yogurt samples exhibited antioxidant potential (1.62-8.95 mM trolox equivalent/g, dw) measured based on scavenging activities of DPPH and ABTS radicals. The average antioxidant potentials of commercial set yogurt containing fruit syrup were significantly (p<0.05) higher than that of cream and plain yogurt. A positive linear correlation was observed between the total phenolic content and the antioxidant capacities, suggesting that phenolic components are likely to contribute significantly to the antioxidant potential of commercial yogurt.

• Horticultural Science & Technology
• /
• v.33 no.5
• /
• pp.784-788
• /
• 2015

A new cultivar 'Picnic' originated from an artificial cross between 'Fuji' and 'Sansa' at National Institute of Horticultural & Herbal Science in 1994. The cultivar was preliminarily selected among the elite siblings for its high fruit quality in 2003. After regional adaptability tests in five districts for four subsequent years as 'Wonkyo Ga-34', it was ultimately selected in 2008. Optimum harvest time is late September. Mature fruit has mean weight of 233 g and is conic with light red skin on a greenish yellow ground and yellowish white flesh. The fruit contains a favorable total soluble solids content at $13.8^{\circ}Brix$ and titratable acidity at 0.43%, which results in gustatory harmony between sugars and acids. It is not resistant to bitter rot or Marssonina blotch. 'Picnic' exhibits a physiological cross compatibility with leading cultivars such as 'Fuji', 'Hongro' and 'Tsugaru'. Tree topology is semi-spreading with a weak growth habit.

• The Korean Journal of Food And Nutrition
• /
• v.27 no.1
• /
• pp.31-42
• /
• 2014

This study was conducted to evaluate the effect of gamma irradiation (0.4, 0.6, 0.8, 1 and 1.5 kGy) on the microbiological, physicochemical and sensory qualities of imported orange during storage at $3^{\circ}C$ for 60 days. Total aerobic bacteria and yeast/mold counts in non-irradiated oranges were 3.59 and 3.75 log CFU/g, and those counts in irradiated oranges at 1.5 kGy were decreased by 1.75 and 2.26 log CFU/g, respectively. Moreover, those counts were decreased significantly according to a dose-dependent manner after gamma irradiation. The pH revealed no significant difference between the control and irradiated samples; however, titratable acidity was decreased significantly according to a dose-dependent manner and storage time. The vitamin C contents were decreased significantly according to a dose-dependent manner and storage time after gamma irradiation. Further, sensory evaluation testing revealed no significant difference between the control and irradiated samples, except 1.5 kGy. Samples irradiated at 1.5 kGy had the lowest values in color, sweetness, sourness, flavor, texture and overall acceptance. The results suggest that gamma irradiation was effective for ensuring microbiological safety; however, irradiated oranges at 1 and 1.5 kGy did not have good physicochemical and sensory qualities. Therefore, we can use the sample irradiated at 0.4~0.6 kGy as optimum-dose to be minimize on quality changes.

• Korean journal of food and cookery science
• /
• v.19 no.5
• /
• pp.609-615
• /
• 2003

In the Kimchi manufacturing industry, the process of brining baechu produces a vast amount of high salinity waste water. To study if this brine can be recycled, the quality characteristics of Kimchi salted by waste brine(F), which was used five times successively, was compared with those salted using water after recycling filtration through sand (F1) and activated carbon (F2) columns. No significant difference in the salinity and soluble solid contents, during fermentation at 10 was observed among the samples, but the salinity and soluble solid contents of the F-sample were slightly higher than in the control. The F1 and control Kimchi showed similar pHs and titratable acidities, while the F-Kimchi had a lower pH and a higher acidity during fermentation. The numbers of total viable cells were highest in the F, and lowest in the F2-Kimchi, while the counts of lactic acid bacteria were lowest in the F-Kimchi. The sensory tests for appearance, odor, taste and overall acceptance showed that the F-Kimchi was the least desirable, the F2-Kimchi had lower sour odor and taste, and a higher toughness, than the others. The F1- and control Kimchi had similar sensory grades for appearance, odor, and tastes, and there were no significant difference in the overall acceptance, showing the possibility of recycling wastewaters as brine for the production of baechu Kimchi.

• Food Science of Animal Resources
• /
• v.30 no.3
• /
• pp.458-465
• /
• 2010

This study evaluated the effect of whey brew cultured by Lactobacillus helveticus ATCC 55163 and Propionibacterium acidipropionici 5020 on bread quality characteristics. Ten and 15% whey brew were added to flour-based bread, after which bread volume, pH, total titratable acidity (TTA), moisture content, water activity, texture, organic acid content, and sensory evaluation were analyzed. The bread volume and TTA of control were the largest among the samples, whereas pH was the lowest. Moisture content did not significantly differ depending on the amount of whey brew added, though water activity was highest in the bread with 10% whey brew. However, hardness was the lowest in bread with 10% whey brew. Propionic acid was not detected while succinic acid, lactic acid, and acetic acid were detected in small amounts in the control compared to the test samples. Succinic acid, acetic acid, and lactic acid content was high in bread with 15% whey brew, with propionic acid present at a very high amount. In terms of sensory evaluation, bread with 10% whey brew had the highest score. As a result, high quality characteristics were associated with the bread with 10% whey brew, whereas long preservation was a characteristic of the bread with 15% whey brew.

• Korean Journal of Food Science and Technology
• /
• v.34 no.6
• /
• pp.1036-1042
• /
• 2002

During storage at $25^{\circ}C$, the effect of gas absorbents, such as carbon dioxide scavenger, ethylene absorber, and their combinations, on respiration characteristics and quality attributes of mature-green Mume fruits packaged in $30\;{\mu}m$ low density polyethylene (LDPE) film was examined. Changes in quality attributes of the fruits were observed in terms of weight loss, titratable acidity, pH, fish firmness, color, water-soluble solid, and chlorophyll contents. In the presence of ethylene absorber $(KMnO_4)$, the physiological injury was remarkably suppressed, and there was no significant injury in Mume fruits at $25^{\circ}C$ for 10 days. Yellowing and softening were also noticeably reduced by the combination of plastic film packaging and inclusion of ethylene absorber. The respiration rate was slower in fruits sealed with ethylene absorber than in those with absorbent-free packaging. Using ethylene absorber, levels of oxygen and carbon dioxide were maintained at 2-3 and 7-8%, respectively, during storage at $25^{\circ}C$ for 10 days. The addition of carbon dioxide scavenger $(Ca(OH)_2)$, negatively affected the quality attributes and respiration characteristics of the fruits. Overall results showed that ethylene removal by gas absorbent in the film packages significantly prolonged the shelf life of the fruits at ambient temperature.

• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1271-1277
• /
• 2000

The extracts from tomatoes, apples, carrots, mallows, watercreses+pine needles, Angelica keiskei Koiz, jujubes and lemons were selected and mixed at the ratio of 3 : 3 : 3 : 1/2 : 1/2 : 1/2 : 1/2 : 1/5 on the basis of sensory evaluation. The mixed extracts were divided into three lots and treated as follows. The first lot was heated for 15 sec at $96^{\circ}C$ without centrifugation and filtration, the second filtered through a ultramembrane filter. For the third one, the ultrafiltrate combined with autoclaved retentates on the membrane filter and the previous centrifugal precipitation. The mixed juices were stored in the glass bottles with atmosphere or in film package with nitrogen gas. And then they were stored at $4^{\circ}$ and $20^{\circ}C$. During storage the treated juices showed $pH\;4.07{\sim}4.10$, titratable acidity $66.35{\sim}84.08$, soluble solid $7{\sim}9^{\circ}Brix$, reducing sugar $5.42{\sim}6.97%$, glucose $1.96{\sim}2.30%$ and fructose $3.46{\sim}4.14%$. The ultrafiltered juices showed yellow color, different from orange color of other treatment lots. Peroxidase activity and microbial population were inhibited by thermal treatment and ultrafiltration. The browning effects of the mixed juice of fruits and vegetables during storage were caused by ascorbic acid oxidation and non-enzymatic browning reaction, which could be reduced by change and packing with nitrogen gas instead of atmosphere inside bottles.