摘要：
An improved rapid analysis for determining the content of insoluble dietary fiber (IDF) in common cereals and some sorts of beans is described in this paper. The procedure includes starch gelatinization in water bath for 20 min at 100 degrees C and 2.5% (w/w) alpha-amylase hydrolyzed reaction followed by neutral detergent wash and acetone extraction. Compared with 1.5 h for filtration (estimated) and 18 h for the enzymatic hydrolysis required by the typical American Association of Cereal Chemists (AACC) method, the filtration and enzymatic treatment procedures in the improved method was completed within 15 min and 1.5 h, respectively. The length of time for the filtration and the enzymatic hydrolysis for the improved method was significantly shortened from 19.5 h (AACC method) to 1.75 h. In addition, orthogonal array design (OAD) has been applied to optimize parameters of the improved method. The recovery yield of microcrystalline cellulose was 97.75% (w/w), in agreement with the result obtained using the typical AACC method, demonstrating the reliability of the improved method. Furthermore, several common cereals and beans were employed to validate the accuracy and universality of this improved method. (C) 2012 Elsevier Ltd. All rights reserved.
关键词：
ACE-inhibitory peptides;Antihypertensive effect;Inhibition pattern;Purification;Rice protein hydrolysate;Stability against gastrointestinal proteases
摘要：
In this study, angiotensin-I converting enzyme (ACE) inhibitory tripeptides from rice protein hydrolysate were purified and their properties were further characterized. Val-Asn-Pro (VNP) and Val-Trp-Pro (VWP) were successfully purified from rice protein hydrolysate through multi-step isolation and purification comprising of ultrafiltration and DA201-C macroporous adsorption resin, followed by a two-step reverse phase high performance liquid chromatography (RP-HPLC). The sequences of tripeptides were separately assayed by using automated protein/peptide sequencer. In addition, the stability of the tripeptides against ACE and simulated gastrointestinal proteases, ACE-inhibitory kinetics, and their antihypertensive effects in vivo were evaluated. Our results showed that VNP (IC50 value of 6.4 mu M) and VWP (IC50 value of 4.5 mu M) were both competitive ACE inhibitors, and stability against ACE and gastrointestinal proteases of pepsin and chymotrypsin. Furthermore, single oral administration of the tripeptides VNP and VWP at 5 mg/kg body weight in spontaneously hypertensive rats (SHRs) significantly decreased the systolic blood pressure (SBP) of 29 and 38 mmHg (P < 0.05), respectively, and the antihypertensive effects of tripeptides could last for 8 h minimally. The identified unique characterization of VNP and VWP may enable the application of rice protein hydrolysate as functional foods or pharmaceuticals against hypertension. (C) 2013 Elsevier Ltd. All rights reserved.
关键词：
ACE-inhibitory peptide;Grass carp protein hydrolysate;Inhibition pattern;Purification;Stability against gastrointestinal enzymes
摘要：
Peptides inhibiting angiotensin-I converting enzyme (ACE, EC. 3.4.15.1) are possible cures of hypertension. Food-derived ACE-inhibitory peptides are particularly attractive because of reduced side effects. Previously, we reported ACE-inhibitory activity of grass carp protein hydrolysates. In this work, we report steps for purifying the ACE-inhibitory peptide from the hydrolysate and its biochemical properties. Following steps of ultrafiltration, macroporous adsorption resin, and two steps of reversed phase high performance liquid chromatography (RE-HPLC), a single Val-Ala-Pro (VAP) tripeptide was identified. The tripeptide with excellent ACE-inhibitory activity (IC50 value of 0.00534 mg/mL) was a competitive ACE inhibitor and stable against both ACE and gastrointestinal enzymes of pepsin and chymotrypsin. This is the first report of food-derived VAP. The identified unique biochemical properties of VAP may enable the application of grass carp protein hydrolysates as a functional food for treatments of hypertension. The developed purification conditions also allow the production of VAP for pharmaceutical applications. (C) 2011 Elsevier Inc. All rights reserved.
摘要：
采用DSC、布拉班德粉质仪和双螺杆挤压机研究燕麦方便面的非膨化挤压生产工艺, 具体分析燕麦粉添加量、混粉水分含量、螺杆转速、机筒温度对方便面糊化度和复水性的影响. 结果表明, 非膨化挤压生产燕麦方便面的较佳工艺条件为燕麦粉添加量40%(燕麦粉与混粉的质量比)、混粉水分含量40%、螺杆转速210r/min, 以及机筒温度Ⅱ区90~95℃、Ⅲ区110~115℃. 在此工艺条件下制得燕麦方便面的糊化度为94.6%、复水时间为 8 m in
