• 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.

• Food Engineering Progress
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• v.21 no.4
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• pp.341-350
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• 2017

The relationship of in vitro starch digestibility and gel strength was investigated at various concentrations (10-30%) of rice cultivars with different amylose contents (27.9, 17.9, and 5.2%). As the rice flour concentration increased, predicted glycemic index decreased, but gel strength increased regardless of amylose contents. Gel strength correlated strongly with amylose content, whereas in vitro starch digestibility was more highly affected by rice flour concentration than by amylose contents. Moreover, the impact of degree of gelatinization on in vitro starch digestibility of high amylose rice was also examined in terms of structural features and rheological properties. The digestion rate of fully gelatinized flour was 1.7 times higher than that of native flour, while the disrupted structure with a different gelatinization degree during starch digestion was visually demonstrated through the X-ray diffraction and molecular distribution analysis. The rice flour changed from an A-type to a V-type pattern and showed difference in crystalline melting. The low molecular weight distribution increased with increasing degree of gelatinization during starch digestion. The apparent viscosity also increased with degree of gelatinization. These results demonstrated that the starch digestibility of rice was more affected by concentration than by amylose content, as well as by the degree of gelatinization due to structural difference.

• The Korean Journal of Food And Nutrition
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• v.36 no.5
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• pp.368-378
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• 2023

Changes in contents of free sugars, amino acids, and fatty acids of legumes were analyzed for each phase of in vitro digestion. In addition, contents of resistant starch in raw and digested pulses were compared. Soybeans, kidney beans, cowpeas, and chickpeas were analyzed. An in vitro digestion model was used to analyze contents of nutrients using LC-MS and GC-MS. Stachyose in kidneybean, cowpea, and chickpea increased as the digestion phase progressed. In four types of legumes, raffinose slightly decreased or showed no significant difference between the Oral phase and the BBMV phase. Content of glucose, a monosaccharide, increased during the BBMV phase. During the digestion phase, levels of free amino acids and free fatty acids also increased. Content of resistant starch was reduced compared to that in the raw material. It was 0.01g/100 g food in soybean, 1.06 g/100 g food in red kidney bean, 0.77g/ 100g food in cowpea, and 0.76 g/100 g food in chickpea. It was confirmed that nutrients in the in vitro digestion model were liberated at each digestion phase with changes in the content of resistant starch. These results are expected to be used as fundamental data for obtaining bioavailability of nutrients.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.355-356
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• 1989

• 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.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.180-183
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• 2008

Digestion properties of 3 types of cereals, white rice, brown rice, and barley, were measured after cooking or grinding. Regardless of the processing methods, white rice showed the highest rate and the greatest extent of digestion, whereas barley showed the lowest values. During the early digestion period, cooked white rice kernels had a larger k (kinetic constant) value than uncooked white rice flour, indicating that cooking induced faster digestion than grinding. In the case of brown rice and barley, the cell wall in cooked kernels remained intact and resulted in a lower k values than those of uncooked flour. However, after 3 hr of digestion, the total digestion extent was greater for the cooked brown rice and barley than that for uncooked flours. The high content of slowly digestible starch (SDS) in cooked brown rice and barley might be due to the starch fraction which was protected by the cell wall. The resistant starch (RS) content, however, was greater for the uncooked flours than that for cooked kernels. The cooked kernels of 3 cereal samples tested showed higher glycemic index (GI) values than the uncooked flours.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.929-939
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• 2011

The effects of micronization on in situ and in vitro nutrient disappearances of wheat, barley and corn were investigated in a series of experiments. In Experiment 1, chemical composition and in situ dry matter disappearance (DMD) of six varieties of wheat were determined. In addition, an in vitro study was completed using ground micronized and unmicronized wheat (var. Kansas). In Experiment 2, three varieties of wheat (Kansas, Sceptre and Laura) and in Experiment 3, three cereal grains (wheat, barley and corn) were either micronized for 1 min to attain internal kernel temperatures of 90-100$^{\circ}C$ or not (controls), and DM, protein and starch disappearances were estimated. In Experiment 2, an in vitro study was also completed using ground micronized and unmicronized wheat (var. Kansas). Wheat samples varied with respect to crude protein (10.0-21.2%), starch (61.6-73.9%), NDF (8.5-11.8%), volume weight (753-842 g/L) and kernel hardness (0.0-32.0). Rate (p = 0.003) and extent (p = 0.001) of in situ DMD differed among wheat varieties. Correlations between in situ kinetics, and chemical and physical properties of wheat varieties showed that protein content was negatively correlated with the rate of disappearance ($r^2$ = -0.77). Micronization of all grains markedly reduced (p = 0.001) the rate and extent of DM, and protein disappearances as compared to control samples. Micronization increased (p<0.05) the digestion of starch in wheat. However, release of ammonia into the incubation medium was markedly reduced (p<0.05), suggesting that micronization increased the resistance of protein to microbial digestion. Disappearances of DM, protein and starch differed (p = 0.001) among cereal grains with wheat>barley>corn. Micronization reduced the rate of DM disappearance (p = 0.011) and slowly degradable protein fractions (p = 0.03), however, increased (p = 0.004) slowly degradable starch fractions of all three cereals. Examination of in situ samples by scanning electron microscopy confirmed that microbial colonization focused on starch granules in micronized grains, and that the protein matrix exhibited resistance to microbial colonization. These results suggest that micronization may be used to increase the ruminal escape value of protein in cereal grains, but may lead to increased starch digestion if grains are finely ground.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.1
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• pp.122-126
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• 2004

A digestion trial in vitro was conducted to study effects of supplementation of NSP (non-starch polysaccharides) degrading enzyme (feed grade) on cell wall degradation and digestibility of nutrients in barley. The slices of barley were soaked in distilled water with or without 0.15% non-starch polysaccharides degrading enzyme. Microscopic examination of the slices showed that the endosperm cell wall of barley was completely degraded by the non-starch polysaccharides degrading enzyme. The residues and supernatant of digesta in vitro were separated by filtration with 0.1 mm nylon fabric. The residues were used for measurement of crude protein, crude fat, crude fiber, and moisture. The supernatant was used for determination of viscosity, as well as amino-nitrogen and glucose content. The results showed that compared with the control, the amino-nitrogen and glucose content of the supernatant increased by 17.58% (p<0.05) and 10.26% (p<0.05), respectively, while viscosity did not change. Enzyme supplementation increased the digestibilities of dry matter, crude protein, nitrogen-free extract, crude fat and crude fiber of barley by 18.1% (p<0.05), 20.3% (p<0.05), 16.4% (p<0.05), 26.9% (p<0.05) and 30.0% (p<0.05), respectively. The present study suggests that cell wall hydrolysis may contribute to improved nutrient digestion in vivo when non-starch polysaccharides degrading enzymes are fed to swine.

• Korean journal of food and cookery science
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• v.24 no.3
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• pp.273-281
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• 2008

To determine the nutritional quality and physical properties of ginseng-chicken meat porridge, 10 kinds of ginsengchicken meat porridge samples containing waxy and/or non-waxy rice were analyzed for in vitro protein digestibility and their degree of starch hydrolysis. Viscosity and spreadness were determined for the gelatinized pastes of the porridge samples. Microphotographs of the starch granules and pastes were studied to confirm structural changes in the rice starch during cooking. The starch paste from non-waxy rice porridge had higher viscosity than the starch paste from the waxy rice porridge; however, in the case of the ginseng-chicken meat porridge, the difference in viscosity was negligible. Microphotograph comparisions between the waxy rice porridge and non-waxy rice porridge indicated apparent differences in the shapes of their starch granules and gels. The granule surface of the non-waxy rice was very rough while that of the waxy rice was very smooth; this difference would lead to organoleptical discrepancy. The added ginseng increased the protein digestibility of the chicken meat; however, the protein digestibility of the ginseng-chicken meat porridge was lower than that of the chicken meat or rice porridge due to inhibited protein digestion by the gelatinized starch. Finally, the rice porridge had increased starch hydrolysis with additions of chicken meat and vegetables.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.365-374
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• 2021

In this study, the effect of enzyme-modified starch used in the preparation of filled hydrogel powder loaded with curcumin (FHP) on redispersibility, thermal and UV stability, and curcumin retention during in vitro digestion was investigated. FHP maintained stability without layer separation when redispersed and showed more stability against UVB than the emulsion powder (EMP). There was no significant difference in the chemical stability of curcumin between rice starch-based filled hydrogel powder (RS-FHP) and enzyme-modified starch-based filled hydrogel powder (GS-FHP). However, the gel matrix of GS-FHP maintained greater stability of lipid droplets in the stomach compared to RS-FHP, thereby improving the retention rate of curcumin after in vitro digestion. GS-FHP could be used as a novel material for developing premixes that require stable formulation and maintenance of functional substances, as it can increase the dispersion stability and retention rate of functional substances after digestion.