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1.
The metabolic responses to South American foods remain to be determined. Using glycemic index (GI) and insulinemic index (II) values as references for therapeutic potential of foods, this study investigated the glucose responses to a typical Venezuelan corn bread (arepa) and to an arepa supplemented with rice bran. Adding rice bran to the bread increased the content of resistant starch and dietary fiber measured as total, soluble, and insoluble dietary fiber. It also increased the protein content of the arepa. Three meals, white wheat bread, 100% corn meal arepa, and an arepa supplemented with 20% rice bran, were administered within a one‐week period. Available starch in the foods was determined to provide 50 g of available carbohydrate per meal. To calculate the indices, bread was used as the reference. The GI and II of the two arepa meals were significantly smaller than the GI and II of white wheat bread, although the differences between the two types of arepas were not significant. It is concluded that Venezuelan arepas (corn meal bread) may have potential health benefits and that the presence of 20% rice bran in the arepa meal did not produce a significant improvement in the glucose response. Due to the presence of antioxidant elements in the supplemented arepa and its higher protein, dietary fiber, and resistant starch content, it may have a potential preventive effect against the development of other pathologies.  相似文献   

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Oat β‐glucan enriched extruded cereals with molecular weights (MWs) ranging from 2,180,000 to 326,000 were produced. Test meals composed of 31 g of available carbohydrate, 8.3–8.7 grams of β‐glucan, and milk were administered to subjects and their postprandial blood glucose levels monitored for 2 hr. White bread plus milk and a control wheat bran cereal plus milk were administered, and white bread alone served as a reference food for estimation of glycemic index (GI) of the cereals, after adjusting for the effect of adding milk to white bread. Both oat bran and wheat bran cereals significantly reduced peak blood glucose rise (PBGR) and area under the curve (AUC) versus white bread alone or white bread plus milk. There was a significant inverse relationship between AUC and log10[weight average MW] (r2 = 0.96, P = 0.0192). There was a significant inverse relationship between PBGR and log10[viscosity] of in vitro extracts from all cereals, including the wheat control (r2 = 0.96, P = 0.0031). However, no significant differences in glycemic responses among the oat bran cereals were found with pairwise comparisons. All cereals were low GI (<55) and were significantly lower than white bread alone or white bread plus milk. Among the oat bran cereals, palatability was positively correlated with MW (r2 = 0.98, P = 0.0110).  相似文献   

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The glycemic index (GI) is an indicator of the relative human glycemic response to dietary carbohydrates in a food. It is determined using a costly and time‐consuming in vivo method. We describe an in vitro analytical method that allows the accurate prediction of the GI of a food product. The method involves digestion of the food product using HCl and enzymes, followed by HPLC analysis of sugars and sugar alcohols. Data from the HPLC analysis combined with the product's compositional information are treated using an artificial neural network to produce a predicted value for the GI of the food product. For the sample set examined (n = 72) consisting of a variety of food types, r2 = 0.93 and the root mean square error of correlation (RMSEC) = 5 GI units. Twenty‐fold cross‐validation yields CVR2 = 0.89, indicating good predictive ability for samples outside the calibration set. The relative standard deviation of the method is 6.6%. This method is rapid and low cost relative to in vivo testing. Due to good ability to predict in vivo GI, it may be a valuable screening tool for determining the relative effect of food ingredients on the glycemic index of a food product.  相似文献   

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The effect of starch–protein–lipid interaction on the in vitro starch digestibility and expected glycemic index (eGI) of kodo millet flour (MF) was investigated. Debranned MF and the flour with lipid removed, protein removed, or both lipid and protein removed (MF‐L‐P) were subjected to digestion assays. The in vitro starch digestibility and eGI of the millet samples and millet starch were compared with rice or wheat flour. Rapidly digestible starch, slowly digestible starch, and resistant starch (RS) of the samples were also calculated. Protease treatment and defatting resulted in significant reduction (P < 0.05) in protein and lipid contents of samples. Significant increases in the in vitro starch digestibility and eGI of samples were observed after removal of protein, lipid, or both. The effect of lipid removal on in vitro starch digestibility of kodo millet was found to be more significant, compared with when proteins were removed. The eGI increased from 49.4 for cooked MF to 62.5 for MF‐L‐P. The eGI of cooked kodo millet starch was significantly lower than that of cooked rice flour. The RS (1.61%) of cooked rice was the least among the samples. The in vitro starch digestibility and eGI of rice were significantly higher than those of MF. Processes applied to kodo millet, such as decortication, that result in the removal of proteins, lipids, or both (especially lipids) would result in an increase in its in vitro starch digestibility and eGI. We therefore advocate for the development of acceptable products from whole millets to maintain its hypoglycemic property.  相似文献   

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《Cereal Chemistry》2017,94(1):110-116
Pulse ingredients (pea and lentil flour, pea protein, and pea fiber) were incorporated into 94 different food products. Products included pastas, breads, crackers, extruded snacks, cookies, cereal bars, and muffins. Products were screened for estimated glycemic index using an in vitro method. Based on the screening results, five products (pasta, bread, cracker, granola bar, and cookie) were selected for in vivo glycemic index (GI) testing. For each control (containing 100% wheat flour), a pulse variant (containing up to 50% pulse ingredients) was developed. Ten healthy subjects consumed each test meal in addition to three control white bread meals on separate days during the in vivo GI testing. GI values of the control and pulse variant meals were 61.3 ± 5.1 versus 54.6 ± 7.6 (pasta), 61.4 ± 5.6 versus 53.4 ± 4.7 (focaccia bread), 46.0 ± 4.2 versus 41.5 ± 3.1 (cracker), 35.4 ± 3.6 versus 34.8 ± 5.0 (granola bar), and 41.6 ± 3.8 versus 37.6 ± 3.0 (cookie). The difference did not reach statistical significance (P > 0.05). Mean GI difference between control and pulse variant was 4.8 ± 2.6, with all pulse variants falling into the low GI category. Palatability scores showed no statistically significant difference (P > 0.05) between the control and pulse variant. The data support substituting wheat flour with pulse ingredients to reduce the GI value without changing palatability of the products.  相似文献   

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The nutritional characteristics of buckwheat starch were studied to identify the possibility for reduced postmeal metabolic responses to various buckwheat products. The in vitro rate of starch hydrolysis and resistant starch (RS) formation in boiled buckwheat groats and in a series of breads, baked with 30-70% of buckwheat flour (BWF) or groats (BWG), respectively, were evaluated in vitro. In parallel, postprandial glucose and insulin responses and also the satiety score to BWG and wheat bread with 50% BWG as compared with the reference white wheat bread (WWB) were studied in healthy humans. The highest concentration of RS was found in boiled BWG (6% total starch basis). The RS level in bread products based on different proportions of BWF or BWG (30-70%) varied from 0.9 to 4.4%. The rate of in vitro amylolysis was significantly lower (P < 0.05) in all buckwheat products in comparison with the reference WWB. The calculated hydrolysis indices (HI) were lowest in boiled BWG (HI = 50) and in bread with 70% BWG (HI = 54). Consumption of boiled BWG or bread based on wheat flour and 50% BWG induced significantly lower postprandial blood glucose and insulin responses compared with the WWB. The calculated glycemic and insulinemic indices (GI and II) for boiled BWG were 61 and 53 and for the buckwheat bread, 66 and 74, respectively. The highest satiety score was found with boiled BWG. It is concluded that buckwheat has potential use in the design of foods with lower GI properties.  相似文献   

7.
Vacuum drying was employed with a vacuum impregnation technique in a semidry state to enrich rice with antioxidants of beetroot juice. The properties of the vacuum‐dried raw and cooked rice grains were characterized. The various raw rice grains (three varieties and two storage time periods) exhibited a significant absorption of beetroot juice, which was evident from the red‐violet beetroot color of the rice, as distinguished from the white color of the control. The color increase (ΔE= 20−40) was linear with the juice content (R2 = 0.96−0.99). Their total phenolic (TP) contents and 2,2‐diphenyl‐2‐picrylhydrazyl radical (DPPH) scavenging activities were enhanced (ΔTP = 21−260 mg of gallic acid equivalents/100 g of rice db and ΔDPPH = 22−64 mg of vitamin C equivalents/100 g of rice db). Their grain integrity was reduced (Δforce = −1 to −63), which was potentially associated with the formation of grain surface cracks (linear relationship of %crack and %juice with R2 = 0.94−0.98). After cooking, the enriched rice grains were linearly elongated with added juice (R2 = 0.88−0.97, up to 1.6‐, 2.0‐, and 2.0‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively), and the overall volume of the cooked rice was increased (likely not linear, up to 3.2‐, 4.3‐, and 4.8‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively). Such improvements in cooking qualities were obtained by this simple vacuum‐drying technique, in comparison to existing rice‐aging processes that are more time consuming. The sensorial scores of the resultant rice products were excellent. Vacuum drying is an effective tool to improve the antioxidant value of rice as well as its cooking quality, and the raw quality remains appreciable. It is a simple and rapid process that could be practical for manufacturing healthy rice products.  相似文献   

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Rye breads made from commercial rye blends lower the postprandial insulin demand and appear to facilitate glucose regulation. However, differences in metabolic responses may occur between rye varieties. In the present work, five rye varieties (Amilo, Evolo, Kaskelott, Picasso. and Vicello) and a commercial blend of rye grown in Sweden were investigated with regard to their postprandial insulin, glucose, and appetite regulation properties in a randomized crossover study in 20 healthy subjects. The rye flours were baked into whole grain breads, and a white wheat bread (WWB) was used as reference (50 g of available starch). Picasso and Vicello rye bread showed lower glycemic indices (GIs) compared with WWB (80 and 79, respectively) (P < .0.05). In addition to the GI, two measures of the glycemic profile (GP and GP(2)) were calculated by dividing the incremental duration of the plasma glucose curve with the incremental glucose peak and squared incremental glucose peak, respectively. Vicello and Picasso ryes were characterized by a higher GP(2) than that of the WWB, suggesting a better regulated course of glycemia. Rye bread made from not only Vicello and Picasso but also Amilo and Kaskelott displayed significantly lower insulin indices (IIs) than WWB (74-82). A high GP and GP(2) and a low GI were related to a lower II and insulin incremental peak. A high content of insoluble fibers and a high GP(2) were related to a higher subjective satiety in the early and late postprandial phase (tAUC 0-60 min and tAUC 120-180 min, respectively). The results suggest that there may be differences in the course of glycemia following different rye varieties, affecting postprandial insulin responses and subjective satiety.  相似文献   

11.
Double‐null partial waxy wheat (Triticum aestivum L.) flours were used for isolation of starch and preparation of white salted noodles and pan bread. Starch characteristics, textural properties of cooked noodles, and staling properties of bread during storage were determined and compared with those of wheat flours with regular amylose content. Starches isolated from double‐null partial waxy wheat flours contained 15.4–18.9% amylose and exhibited higher peak viscosity than starches of single‐null partial waxy and regular wheat flours, which contained 22.7–25.8% amylose. Despite higher protein content, double‐null partial waxy wheat flours, produced softer, more cohesive and less adhesive noodles than soft white wheat flours. With incorporation of partial waxy prime starches, noodles produced from reconstituted soft white wheat flours became softer, less adhesive, and more cohesive, indicating that partial waxy starches of low amylose content are responsible for the improvement of cooked white salted noodle texture. Partial waxy wheat flours with >15.1% protein produced bread of larger loaf volume and softer bread crumb even after storage than did the hard red spring wheat flour of 15.3% protein. Regardless of whether malt was used, bread baked from double‐null partial waxy wheat flours exhibited a slower firming rate during storage than bread baked from HRS wheat flour.  相似文献   

12.
The seeds of Parana pine (Araucaria brasiliensis syn. Araucaria angustifolia), named pinh?o, are consumed after cooking and posterior dehulling, or they are used to prepare a flour employed in regional dishes. Native people that live in the South of Brazil usually consume baked pinh?o. As a result of cooking, the white seeds become brown on the surface due to the migration of some tinted compounds present in the seed coat. In this work, the proximate composition, minerals, flavonoids, and glycemic index (GI) of cooked and raw pinh?o seeds were compared. No differences in moisture, lipids, soluble fiber, and total starch after boiling were found. However, the soluble sugars and P, Cu, and Mg contents decreased, probably as a consequence of leaching in the cooking water. Also, the boiling process modified the profile of the phenolic compounds in the seeds. No flavonols were detected in raw pinh?o seeds. The internal seed coat had a quercetin content five times higher than that of the external seed coat; also, quercetin migrated into the seed during cooking. The internal seed coat had a high content of total phenolics, and seeds cooked in normal conditions (with the seed coat) showed a total phenolics content five times higher than that of seeds cooked without the seed coat. Cooking was then extremely favorable to pinh?o seeds bioactive compounds content. The carbohydrate availability was evaluated in a short-term assay in humans by the GI. The GI of pinh?o seeds cooked with the coat (67%) was similar to that of the seeds cooked without a coat (62%) and lower than bread, showing that cooking does not interfere with starch availability. The low glycemic response can be partly due to its high content of resistant starch (9% of the total starch).  相似文献   

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Brans of specialty sorghum varieties (high tannin, black, and black with tannin) were used to investigate the effects of sorghum phenolic compounds on starch digestibility of soft and hard sorghum endosperm porridges. Endosperms of varieties with the highest and lowest grain hardness index were mixed with brans of specialty sorghum varieties in the ratio of 85:15 and cooked into porridges with distilled water using a Rapid Visco Analyzer. Brans of condensed tannin containing sorghum varieties (high‐tannin and black with tannin sorghums) significantly (P < 0.05) decreased starch digestibility and estimated glycemic index (EGI) and increased resistant starch (RS) content of endosperm porridges. However, the addition of phenolic‐rich tannin‐free (mostly anthocyanins) black sorghum bran significantly (P < 0.05) increased starch digestibility and EGI but did not affect RS content of endosperm porridges. The disparate effects with black bran may, in part, result from its larger particle size and different bran structure compared with other sorghum varieties evaluated. Thus, our study showed that not only presence of phenolic compounds in the brans but also structural differences of specialty sorghum brans can have significant effects on starch digestibility.  相似文献   

15.
Brown rice kernels (japonica type) were soaked in water at different temperatures (25 or 50°C) before cooking to a moisture content of 20 or 30%. Soaked brown rice was cooked in either the soaking water (SW) or in distilled water (DW) (rice solids to water ratio 1:1.4). Color, texture, and in vitro digestive properties of the cooked rice were examined. When the soaking temperature was higher (50°C vs. 25°C), water absorption and starch leaching were greater. To reach 20% moisture, the rice required 1 hr of soaking at 50°C but 2 hr of soaking at 25°C. Both the moisture content of the soaked rice and the soaking temperature affected the texture of the cooked brown rice. Rice that attained 20% moisture content during soaking was harder and less adhesive when cooked compared with rice that attained 30% moisture content. The rice soaked at 50°C was slightly softer but more adhesive when cooked than rice soaked at 25°C. The soaking temperature and moisture content of the rice kernels also affected the digestive properties of the cooked rice. The cooked brown rice that had attained 30% moisture before cooking was digested to a greater extent than rice that had attained 20% moisture. Even at equal moisture content, the rice soaked at the higher temperature (50°C) was digested more readily. It was assumed that the amount of soluble material leached during soaking differed according to the soaking temperature and moisture content, which subsequently affected the texture and digestive properties of the cooked brown rice. The rice cooked in its own soaking water was harder and more adhesive, had higher levels of resistant starch (RS), and exhibited smaller glycemic index (GI) values than its counterpart cooked with distilled water. This result indicated that the soluble material leached during soaking made the cooked rice harder and less digestible, perhaps due to interactions between these molecules and the gelatinized rice during cooking.  相似文献   

16.
蒸煮过程中稻米水分状态的质子核磁共振谱测定   总被引:6,自引:4,他引:6       下载免费PDF全文
对3种稻米蒸煮过程中水分的状态进行了1H-NMR测定。结果表明, 不同品种的原料稻米具有相近的弛豫特征。但在蒸煮过程中,纵弛豫时间会因品种的不同而呈现出显著的差异。分析结果认为,稻米中水分的存在状态有自由水、构造水和结合水等3种形式。蒸煮过程中各种稻米水分状态的差异与谷粒中有机物的理化特性密切相关,并可能是导致米饭具有不同食味特性的重要原因。  相似文献   

17.
The objective of this study was to investigate the effects of milling and cooking conditions of cooked rice prepared from cultivar Koshihikari on in vitro starch digestibility and in vivo glucose response in humans. In addition, compression and adhesiveness tests were conducted for texture analysis of the cooked rice. Brown rice (BR) and surface‐abraded BR (SABR, ≥99.5% of the original weight) were digested more slowly than white rice (91% of the original weight) when cooked rice grain was used for the in vitro test, but they were digested more rapidly in the initial stage of the reaction when cooked rice ground by a meat grinder was used. The increase in water added for cooking significantly increased the extent of starch digestion with BR and SABR. The changes in blood glucose levels after the ingestion of cooked rice were dependent on the sample type. The cooking conditions dramatically influenced the glucose response after the ingestion of BR. A significant correlation was found between blood glucose levels at 45 min and the extent of starch digestion with ground samples, whereas no relationship was found with cooked rice grain samples for in vitro digestibility.  相似文献   

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The purpose of this study was to develop highly accurate regression models with texture parameters of cooked milled rice grains for predicting pasting properties in terms of quality index of rice flour. Two methods were adopted as the texture measurement to acquire predictors for the models. In the calibration set, all the multiple regression models by a single‐grain method exhibited a higher R2 than those by a three‐grain method. Each of the former models also showed a lower SEP and a higher RPD in the validation set. The prediction performance was best for consistency (RPD = 2.4). The single‐grain method was more advantageous for the pasting prediction. These results suggest that the models based on grain texture could predict rice flour quality.  相似文献   

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