• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.116-122
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• 1990

In order to improve the shelf life of Tofu, the effect of calcium chloride or acetic acid as coagulants were investigated for microbial and physicochemical changes during the storage in different kinds of soaking solution. The soaking water of Tofu prepared from calcium chloride was found to be spoiled after 15-17 hours of storage at $30^{\circ}C$, by reaching the bacteria count to 10million per ml. The shelf life of the Tofu prepared from acetic acid was better than those prepared by calcium chloride. For the effect of soaking solution on storage life, soaking Tofu in 0.1% acetic acid was found to be more effective than soaking in other solutions of 3% NaCl or 0.1% K-sorbate. The optical density of soaking solution of Tofu increased in proportion to spoilage, and in case of soaked Tofu in 3% sodium chloride and 0.1% K-sorbate solution, it greatly increased. Titratable acidity, and amino nitrogen contents in soaking solution increased as spoilage of Tofu progressed, but pH decreased the early period, one or two days, of stored Tofu and then increased.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.210-224
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• 2018

Warqe (Ensete ventricosum) has been traditionally fermented in an earthen pit to yield a carbohydrate-rich food product named kocho, for generations. A fermentation enhancer (gammaa) was added to this fermenting mass to enhance the fermentation process. The objectives of this study were to assess the physicochemical properties and microbiota of the kocho fermentation enhancer culture to reduce losses. Cross-sectional study design was implemented to collect 131 gammaa samples on the first day of fermentation. The samples were further classified into four groups according to the duration of fermentation (14, 21, 30, and 60 days) practised in various households traditionally. The results showed that the fermentation time significantly affected the physicochemical properties and microbial load of gammaa (p < 0.01). As the fermentation progressed from day 1 to 60, the pH decreased and the titratable acidity increased. The total coliform, Enterobacteriaceae, aerobicmesophilic bacteria (AMB), yeast, and mould counts were significantly reduced at the end of fermentation. In contrast, the number of lactic acid bacteria (LAB) increased significantly until day 30 of fermentation, because of the ability of the LAB to grow at low pH. Lactobacillus species from LAB isolates and Enter obacteriaceae from AMB isolates were the most abundant microorganisms in gammaa fermentation. However, the Enterobacteriaceae and Lactobacilli species count showed decreasing and increasing trends, respectively, as the fermentation progressed. These isolates must be investigated further to identify the species and strain, so as to develop gammaa at the commercial scale.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5693-5699
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• 2014

The influence of the flour types, including bread flour and cake flour on sourdough preparation was investigated. As starters, mixed probiotic microorganisms, including Bifidobacterium longum KCTC 5734, Enterococcus faecium KCTC 13410, and Lactobacillus acidophilus KCTC 3925, or Saccharomyces cerevisiae fermented separately for 15h at $30^{\circ}C$, were combined and then fermented for 10h at $30^{\circ}C$. The combined process with cake flour showed a 100-fold and two-fold increase in [$H^+$] and titratable acidity, respectively. This was also reflected in the viable cell counts and lactate concentration in sourdough. These results show that bread flour and cake flour may be useful for the production of sourdough.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.317-323
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• 1999

Immature plums(Prunus salicina L.) were coated with edible coatings, calcium-added methyl cellulose(CaMC) and hydroxy propyl methyl cellulose-15(CaHPMC-15). Weight loss and respiration rate of immature plums coated with CaMC and CaHPMC-15 were lower only at the earlier storage period. The titratable acidity of plums was decreased and pH was increased during storage, Soluble pectin, pectinesterase, and polygalacturonase activity as the marker of softening were commonly increased with storage time, but those increases were lower in CaMC and CaHPMC-15-coated plums. Mechanical firmness became significantly soft during storage, while the coated plums were remained harder. As a result of sensory evaluation, softening of plum tissue was found during storage, but the coated plums had the harder texture. These data suggest that the application of CaMC or CaHPMC-15 coatings into immature plums can reduce the postharvest softening during storage.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2058-2071
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• 2015

A comparative study was conducted to evaluate precision and accuracy in controlling the temperature dependence of encapsulated microbial time-temperature integrators (TTIs) developed using two different emulsification techniques. Weissela cibaria CIFP 009 cells, immobilized within 2% Na-alginate gel microbeads using homogenization (5,000, 7,000, and 10,000 rpm) and Shirasu porous glass (SPG) membrane technologies (10 μm), were applied to microbial TTIs. The prepared micobeads were characterized with respect to their size, size distribution, shape and morphology, entrapment efficiency, and bead production yield. Additionally, fermentation process parameters including growth rate were investigated. The TTI responses (changes in pH and titratable acidity (TA)) were evaluated as a function of temperature (20℃, 25℃, and 30℃). In comparison with conventional methods, SPG membrane technology was able not only to produce highly uniform, small-sized beads with the narrowest size distribution, but also the bead production yield was found to be nearly 3.0 to 4.5 times higher. However, among the TTIs produced using the homogenization technique, poor linearity (R²) in terms of TA was observed for the 5,000 and 7,000 rpm treatments. Consequently, microbeads produced by the SPG membrane and by homogenization at 10,000 rpm were selected for adjusting the temperature dependence. The E_a values of TTIs containing 0.5, 1.0, and 1.5 g microbeads, prepared by SPG membrane and conventional methods, were estimated to be 86.0, 83.5, and 76.6 kJ/mol, and 85.5, 73.5, and 62.2 kJ/mol, respectively. Therefore, microbial TTIs developed using SPG membrane technology are much more efficient in controlling temperature dependence.

• Current Research on Agriculture and Life Sciences
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• v.8
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• pp.83-88
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• 1990

This experiment was conducted to investigate the effect of $CO_2$ treatment on quality of strawberry during storage. Gas composition in polyethylene(P.E.) film bag during storage was changed markedly at early stage of storage and then kept at the level of 8-9% $CO_2$and 1-2% $O_2$. Weight loss and decay were restricted by $CO_2$ pretreatment and P.E. film packaging. Titratable acidity, PH and soluble solids were not changed greatly during storage. Firmness of flesh was increased by $CO_2$ treatment till 14 days of storage and decrease of a value reduced by $CO_2$ treatment and P.E.film packaging, too. Ascorbic acid contents were more high in not packed samples than packed untill 14 days of storage but after that those were more high in P.E.film packed and $CO_2$ treated samples.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.8-13
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• 2002

The isoflavone glycosides are hydrolyzed by ${\beta}$-glucosidase from gut microbes to the bioactive aglycones. However, the specific bacteria from the human intestinal tract that are involved in the metabolism of these compounds are not known. This study was undertaken to develop a fermented soymilk which converts isoflavones to the more bioactive aglycones form using a Bifidobacterium strain. The ${\beta}$-glucosidase activity of 15 Bifidobacterium strains were measured during cell growth. Among them, Bifidobacterium sp. Int-57 was selected for this study, because it has the highest ${\beta}$-glucosidase activity. Growth, acid development, ${\beta}$-glucosidase activity, and the hydrolysis of daidzin and genistin were investigated in four soymilks inoculated with Bifidobacterium sp. Int-57. After 12 h of fermentation, the counts of viable Bifidobacterium sp. Int-57 in all the soymilks reached a level of more than $10^8$ cfu/ml, which was then maintained. The pH of soymilks started to decrease rapidly after 6 h of fermentation and leveled off after 18 h. The titratable acidity of BL# 1 soymilk, BL#2 soymilk, and JP#l soymilk increased from 0.18 to 1.21, 1.15, and $1.08\%$ over the fermentation period, respectively. After 24 h of fermentation, the $\beta$-glucosidase activity in BL#1 soymilk, BL#2 soymilk, JP#l soymilk, and JP#2 soymilk increased to 59.528, 40.643, 70.844, and 56.962 mU/ml, respectively. The isoflavone glycosides, daidzin and genistin, in soymilks were hydrolyzed completely in the relatively short fermentation time of 18 h. These results show that Bifidobacterium sp. Int-57 can be used as a potential starter culture for developing fermented soymilk which has completely hydrolyzed isoflavone glycosides.

• Korean Journal of Human Ecology
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• v.23 no.3
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• pp.467-481
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• 2014

We investigated the effects of Mulberry leaves fermented enzyme liquid(MLE) addition on the quality of Kimchi which were fermented at $5^{\circ}C$ during 30 days. MLE was added to salted cabbage at concentrations of 0%(C), 0.4%(MLE1), 0.8%(MLE2), and 1.2%(MLE3) (w/w). pH in Kimchi added upon 1.2% of MLE, was higher than that of Kimchi without MLE after 12 days of fermentation. The titratable acidity was increased by the addition of MLE, and particularly Kimchi added 1.2% of MLE showed the slowest changed level. The degree of salinity were decreased in Kimchi with MLE as well as control group. However, MLE1 showed significantly lower salinity than MLE2, MLE3 and control group (p<0.001). L, a, b values of control group indicated significantly higher than the Kimchi with enzyme liquid concentrations(MLE1~MLE3). As compared with the control group, the cutting force in treated groups were increased during the fermentation period, and especially MLE3 showed the highest value of hardness. Moreover, that growth of lactic acid bacteria and total bacteria were inhibited by the addition of MLE. In the sensory assessment, the color, taste, and overall preferences were higher in MLE2 than control group and MLE1, MLE3. The acceptability of MLE as an additive in Kimchi among middle school students was higher than in the control sample, with an optimum additive of 0.8% MLE, based on the lowest volume of leftovers. Therefore, it was confirmed that addition of 0.8% MLE appears to be an acceptable approach to enhance the quality of Kimchi without reduction of acceptability.

• Food Science and Preservation
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• v.7 no.2
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• pp.133-138
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• 2000

The research was conducted to measure the effect of temperature on respiratory and quality characteristics of 'Tsugaru' apple(Malus domestica Borkh) during storage at 4$^{\circ}$C, 10$^{\circ}$C and 20$^{\circ}$C. Respiration rate of the apple just after harvest was 7.57 mL CO$_2$/kg/h at 20$^{\circ}$C. It was decreased rapidly and was 2.86 mL CO$_2$/kg/h after storage for 45 days at 20$^{\circ}$C. The apples showed the highest ethylene production rate at 10$^{\circ}$C and 20$^{\circ}$C after 14 days, and at 4$^{\circ}$C after 28 days during storage. Weight of the apple was reduced by 2.9% after 120 days at 4$^{\circ}$C and by 6.1% after 45 days at 20$^{\circ}$C. Color difference of peel and pH increased with the temperatures but titratable acidity and flesh firmness showed the reverse trends during storage. According to the subjective quality test, it could be suggested that the shelf-life of the apple is 86 days at 4$^{\circ}$C, 65 days at 10$^{\circ}$C and 37 days at 20$^{\circ}$C, respectively.

• Food preservation and processing industry
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• v.3 no.1
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• pp.42-46
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml h-1 m-2 nun-1 at $5^{\circ}C$ and $99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%$ CO2 + 1 or $20\%\;O_2, \;8\%\;CO_2+1$ or $20\%\;O_2$, or $12\%\; CO_2+\;20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2 +\;1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SCC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene Production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown.