• The Korean Journal of Food And Nutrition
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• v.15 no.1
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• pp.29-35
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• 2002

N-nitrosamine(NA) contents depending on simulated gastric digestion were analyzed with 12 kinds of diets collected from institutional food service those diets were estimated the total NA amounts including both intake from food directly and its endogenous formation in human body from simulated gastric digestion. NA was determined in dishes of meats, fishes and vegetables before and after simulated gastric digestion. Before digestion, N-nitrosodimethylamine (NDMA) contents ware from not detected(ND) to 4.8$\mu\textrm{g}$/kg in dishes of meats and fishes. After digestion, its contents increased and the highest level was 3.0 $\mu\textrm{g}$/kg in panbroiled dried anchovy. In vegetable dishes, NDMA was detected as ND∼trace before and after digestion. The contents of NDMA in diets collected from institutional food service were 0.20∼0.78$\mu\textrm{g}$/kg 0.43 ∼ 0.80$\mu\textrm{g}$/kg before and after digestion, respectively. The average intake of NA per day to Korean, based on the above data, was 0.60 ∼ 2.34$\mu\textrm{g}$/day/ person. The maximum daily intake of NA was deduced to 5.15$\mu\textrm{g}$/day/person when considering NA amounts formed endogenously by simulated gastric digestion.

• Mycobiology
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• v.39 no.1
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• pp.67-69
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• 2011

A cell-free extract of Saccharomyces cerevisiae containing the angiotensin I-converting enzyme (ACE) inhibitory peptide was treated in a successive simulated gastric-intestinal bioreactor (step 1: amylase digestion, step 2: gastric fluid digestion, step 3: intestinal fluid digestion) to illustrate the absorption pattern of antihypertensive ACE inhibitory peptide, and the ACE inhibitory activities of each step were determined. Total ACE inhibitory activities of step 1, step 2, and step 3 were 55.96%, 80.09%, and 76.77%, respectively. The peptide sequence of each steps was analyzed by MS/MS spectrophotometry. Eleven kinds of representative peptide sequences were conserved in each step, and representative new peptides including RLPTESVPEPK were identified in step 3.

• Korean Journal of Food Science and Technology
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• v.47 no.6
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• pp.793-796
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• 2015

The in-vitro starch digestibility of white and brown rice flours was continuously characterized from a rheological point of view. Specifically, the in-vitro viscosities of the rice digesta samples were monitored under simulated oral, gastric, and intestinal conditions. A trend of decreasing viscosities in all the digesta samples was observed during the in-vitro digestion. After cooking, the brown rice sample exhibited lower viscosity than that of the white rice flour due to the presence of more non-starch components. A similar tendency was observed during the simulated oral and gastric digestions. However, the viscosity crossover between the white and brown rice samples was observed during intestinal digestion. In addition, the amount of glucose released from the brown rice flour was significantly lower than that from the white rice flour. Thus, the slower rate of starch hydrolysis in the brown rice flour could be related to its in-vitro rheological behaviors.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1310-1314
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• 2012

Gastrointestinal digestibility of new proteins inserted in the food supply is a significant parameter for assessing the safety of GM foods based on the assumption that digestive stability is undesirable. In this study, we performed in vitro digestion of CP4EPSPS, a new protein, expressed in genetically modified (GM) soybean in order to evaluate its digestibility in three different ratios of simulated gastric fluid with preheating. Ratios of GM soybean to simulated gastric fluid were 2:2, 2.5:1.5, and 1.5:2 and preheating was conducted at $100^{\circ}C$ for 5 min. Electrophoresis and Western blotting were used to confirm changes in soybean protein patterns and CP4EPSPS gene expression after in vitro digestion. At ratios in which the amount of gastric fluid was equal to (2:2) or relatively higher than that of soybean (1.5:2), no CP4EPSPS (47.4 kDa) protein was detected after 15 seconds of simulated gastric fluid incubation, the earliest time interval evaluated. However, when the ratio of GM soybean to gastric fluid was 2.5:1.5, CP4EPSPS was detected in 5 min and gradually decreased according to time. After preheating, no CP4EPSPS protein was detected after 15 seconds under all conditions. From these results, we concluded that the digestibility of CP4EPSPS in simulated gastric fluid increased upon preheating. Accordingly, we suggest that it is important to account for the ratio of gastric fluid to GM food in in vitro digestibility assessment models of GM food.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.925-930
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• 2004

Antioxidant activity and antimutagenic activities with and without simulated gastric digestion of hot water extracts from white and yellow onions were investigated as compared to BHT and ascorbic acid as control Contents of total phenol and flavonoid in hot water extract of yellow onion were higher than those of white one. The scavenging activity of hydrogen peroxide of both extracts were increased in direct proportion to added their concentration. Antioxidant activity and reducing power of the hot water extract were elevated through analysis of $\beta-carotene-linoleate$ system and were lower than those of BHT and ascorbic acid. Antimutagenic activity after simulated gastric digestion of hot water extract of white and yellow onions was observed against mutagen IG and MNNG on Salmonella typhimurium TA80 and TA100. Extract of yellow onion was higher in antimutagenic activity than that of white one. In conclusion, these results suggested that phenol and flavonoid in hot water extract from yellow and white onions may play an important role in the antioxidant and antimutagenic activities.

• Korean journal of food and cookery science
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• v.33 no.2
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• pp.181-189
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• 2017

Purpose: This study was conducted to examine the effects of the starch concentration of filled hydrogel and the addition of ${\alpha}-amylase$ and simulated mastication processing in an oral phase on lipid digestion and ${\beta}-carotene$ bioaccessibility of filled hydrogels. Methods: Lipid digestion and ${\beta}-carotene$ bioaccessibility of the filled hydrogels were measured after the samples were passed through an in vitro gastrointestinal tract model consisting of oral, gastric, and small intestinal phases. Results: The initial rate and final extent of lipid digestion were higher in the filled hydrogels than in the emulsion when the filled hydrogels were treated in an oral phase without simulated mastication processing and addition of ${\alpha}-amylase$, regardless of starch concentration. However, when the filled hydrogels were minced using mortar and pestle for 2 min and were exposed to ${\alpha}-amylase$, the filled hydrogel fabricated with 5% starch showed the lowest lipid digestion rate and extent compared to the emulsion and other filled hydrogels. Bioaccessibility of ${\beta}-carotene$ was higher in the filled hydrogels than in the emulsion, regardless of the digestion method performed in an oral phase and starch concentration. However, there were appreciable differences in bioaccessibility of the filled hydrogels depending on whether or not simulated mastication and addition of ${\alpha}-amylase$ were employed. Conclusion: These results suggested that the rheological properties of initial filled hydrogels and simulated mastication processing in an oral phase plays an important role in determining the lipid digestion and ${\beta}-carotene$ bioacccessibility entrapped within filled hydrogels.

• Animal Bioscience
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• v.35 no.10
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• pp.1592-1605
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• 2022

Objective: The objective of this study was to select an effective in vitro digestion-fermentation model to estimate the effect of decreasing dietary crude protein (CP) on odor emission during pig production and to suggest potential prediction markers through in vitro and in vivo experiments. Methods: In the in vitro experiment, three diet formulations with different CP contents (170 g/kg, 150 g/kg, and 130 g/kg) but containing the same standardized ileal digestible essential amino acids (SID-EAA) were assessed. Each diet was evaluated by two different in vitro gastric-intestinal phase digestion methods (flask and dialysis), combined with fresh pig feces-ferment inoculation. Eighteen growing barrows (31.9±1.6 kg) were divided into three groups: control diet (180 g CP/kg, without SID-EAA adjustment), 170 g CP/kg diet, and 150 g CP/kg diet for 4 weeks. Results: The in vitro digestion results indicated that in vitro digestibility was affected by the gastric-intestinal phase digestion method and dietary CP level. According to the gas kinetic and digestibility results, the dialysis method showed greater distinguishability for dietary CP level adjustment. Nitrogen-related odor compounds (NH₃-N, indole, p-cresol, and skatole) were highly correlated with urease and protease activity. The feeding study indicated that both EAA-adjusted diets resulted in a lower odor emission especially in p-cresol and skatole. Both protease and urease activity in feces were also closely related to odor emissions from nitrogen metabolism compounds. Conclusion: Dialysis digestion in the gastric-intestinal phase followed by fresh fecal inoculation fermentation is suitable for in vitro diet evaluation. The enzyme activity in the fermentation and the fecal samples might provide a simple and effective estimation tool for nitrogen-related odor emission prediction in both in vitro and in vivo experiments.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1560-1565
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• 2004

There are about 50 kinds of salted and fermented fish in Korea, and they have been used as a necessity for the preparation of kimchi. There is next to nothing for the studies of finding out the cause of N-nitrosamine formation by using the salted and fermented anchovies. In order to predict the possibility of N-nitrosamine formation and mutagenicity from gastric digestion of Korean Jeotkal, correlation of N-nitrosodimethylamine (NDMA) and mutagenicity of the salted and fermented anchovy under simulated gastric digestion was investigated through mixture system of nitrate, thiocyanate, formaldehyde and ascorbic acid to the anchovy product aged at room temperature (18~20$^{\circ}C$) for 60 days. NDMA formation of fermented anchovy under simulated gastric digestion was accelerated by the increase of nitrate, thiocyanate and formaldehyde concentration and was inhibited by the addition of ascorbic acid as an inhibitor, showing that its inhibition rate was 71.3% at 4 mM as compared with control group. Mutagenicity in anchovy digest added with several level of nitrite, thiocyanate and formaldehyde was increased, while it was markedly decreased in addition of ascorbic acid.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.346-355
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• 2021

Ngoc Linh ginseng is one of the most valuable endemic medicinal herbs in Vietnam. In this study, Ngoc Linh ginseng callus was fermented by Lactobacillus plantarum ATCC 8014 (at 6, 7, and 8 log CFU/ml) to evaluate the extraction efficiency of bioactive compounds. The post-fermentation solution was spray-dried using maltodextrin with or without Stevia rebaudiana (3% and 6% v/v) as the wall material. Bioactive compounds such as polyphenols, polysaccharides, and total saponins, and L. plantarum viability during fermentation and after spray-drying, as well as under simulated gastric digestion, were evaluated in this study. The results showed that probiotic density had a significant effect on bioactive compounds, and L. plantarum at 8 log CFU/ml showed the best results with a short fermentation time compared to other tests. The total content of polyphenols, polysaccharides, and saponins reached 5.16 ± 0.18 mg GAE/g sample, 277.2 ± 6.12 mg Glu/g sample, and 4.17 ± 0.15 mg/g sample, respectively after 20 h of fermentation at the initial density of L. plantarum (8 log CFU/ml). Although there was no difference in the particle structure of the preparation, the microencapsulation efficiency of the bioactive compound in the samples containing S. rebaudiana was higher than that with only maltodextrin. The study also indicated that adding S. rebaudiana improved the viability of L. plantarum in gastric digestion. These results showed that S. rebaudiana, a component stimulating probiotic growth, combined with maltodextrin as a co-prebiotic, improved the survival rate of L. plantarum in simulated gastric digestion.

• Food Science of Animal Resources
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• v.39 no.6
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• pp.1000-1007
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• 2019

This study investigated protein digestibility of beef puree in infant and adult in vitro digestion models. The simulated digestive juices for infant and adult were prepared. Protein digestibility of beef puree was calculated in the gastric and gastrointestinal compartments. The 10% trichloroacetic acid soluble nitrogen and α-amino group contents of gastric digesta were lower in the infant in vitro digestion model than those in the adult in vitro digestion model (p<0.05). In addition, the gastrointestinal digesta from the infant in vitro digestion model had lower value of the 10% trichloroacetic acid soluble nitrogen and α-amino group contents than those of the adult in vitro digestion model (p<0.05). The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the remarkable bands of actin and myosin light chain B were found in the digesta of beef puree from the infant in vitro digestion model. The results of this study revealed the lower protein digestibility of beef puree in infants compared to that in adults. Therefore, the development of ways to increase digestibility of meat protein can improve the nutritional quality of meat products for infants.