Molecular weight of guar gum affects short-chain fatty acid profile in model intestinal fermentation

Dietary fiber exerts many beneficial physiological effects; however, not all types of dietary fiber display the same effects. Partially hydrolyzed guar gum (PHGG), a lower molecular weight form of guar gum, is more easily incorporated into food, but may have less pronounced physiological effects than the native form. The aim of this study was to identify differences in intestinal fermentability based on the molecular weight of guar gum. Guar gum of four molecular masses (15, 20, 400, and 1,100 kDa) was fermented using a batch in vitro fermentation system. Human fecal inoculum was the source of microbes. The 400-kDa fraction produced the greatest concentrations of total short-chain fatty acid (SCFA) at 8 h and the highest amounts of butyrate at 24 h. At 24 h, the 400-kDa fraction produced more total SCFA and propionate than the 15 kDa, but was not different than 20 kDa or 1,100 kDa fractions. The molecular weight of guar gum was positively correlated with acetate production and negatively correlated with propionate production. This study concludes that 400-kDa guar gum may be optimal for intestinal fermentability. In conclusion, the molecular weight of guar gum affects in vitro fermentability and should be considered when adding to a food or beverage.     

部分水解瓜尔豆胶对高脂高糖饮食诱导小鼠代谢紊乱的调节作用

部分水解瓜尔豆胶(partially hydrolyzed guar gum,PHGG)是一种有益于代谢平衡的可溶性膳食纤维,但其对糖脂代谢紊乱的调节效果及其潜在机制尚不明确.利用高脂高糖饮食诱导小鼠16周,使其产生明显的脂代谢紊乱和胰岛素抵抗,进一步通过检测小鼠糖耐量、血清生化指标、脂肪形态、肠道短链脂肪酸及相关mRNA的表达,考察PHGG对模型小鼠的糖脂代谢稳态及肠道环境的调节作用.结果表明:长期高脂高糖饮食条件下,PHGG组小鼠比模型组小鼠的体质量增长率减缓,空腹血糖降低,葡萄糖耐量和胰岛素耐量显著提升;血清中的甘油三酯、总胆固醇、低密度脂蛋白胆固醇和游离脂肪酸可分别降低21.56％、32.67％、25.66％和22.91％,明显抑制了脂肪积累.PHGG将肠道胰高血糖素样肽-1的分泌提升并恢复到67.76 pmol/L,盲肠中的丁酸含量比模型组提升了7.14倍.定量PCR显示,PHGG干预后小鼠短链脂肪酸受体GPR43的蛋白表达水平比模型组提升了63.30％.本研究表明,PHGG通过调节短链脂肪酸影响脂联素、胰岛素的分泌,进而改善高脂高糖饮食引起的糖脂代谢紊乱,可以应用于辅助糖脂代谢调控的功能性食品开发中.     

部分水解瓜尔胶的酶法制备及其对面包烘焙特性的影响〖

为研究部分水解瓜尔胶(partially hydrolyzed guar gum,PHGG)对面包烘焙特性的影响,以瓜尔胶(guar gum,GG)为原料,采用酶解法制备PHGG。在比较PHGG和GG基本组成差异的基础上,采用质构仪、低场核磁共振仪、差示扫描量热仪和九分嗜好评分法研究PHGG添加量对面包烘焙品质及储藏特性的影响。基本组成分析结果表明,与GG相比,PHGG的黏度和分子质量显著下降,分别为(118.80±0.62)mPa·s、8.1kDa。烘焙品质分析结果表明,添加PHGG对面包比容无显著影响,但可显著降低面包的烘焙损失率,从(14.08±0.77)%降低至(11.73±1.29)%;并赋予了面包更好的色泽。面包储藏特性研究结果表明:在7d储藏期内,PHGG显著提高了面包的保水率,从(77.48±0.43)%增加至(85.58±4.15)%;改善了面包的内聚性和回复性;促进了面包内部水分的迁移,进而增加了面包内部结构的稳定性,具有延缓面包老化的效果。此外,感官评价结果表明,PHGG添加组面包的感官评分高于对照组面包。PHGG添加量(质量分数)为2.5%~4.5%时可显著改善面包的烘焙品质、储藏特性和感官品质,研究旨在为PHGG在食品加工中的应用提供一定理论参考。     

低分子量瓜尔豆胶膳食纤维对面团流变学特性和馒头品质

研究低分子质量瓜尔豆胶膳食纤维(partially hydrolyzed guar gum,PHGG)对面团流变学和馒头品质影响。mixolab实验结果表明,PHGG对面筋蛋白有弱化作用;添加适量的PHGG能延长面团的形成时间和稳定时间;PHGG能一定程度的抑制淀粉回生。在PHGG添加量3%时,馒头比容达到最大,相比对照增大15.5%。随着PHGG添加量增加馒头硬度、弹性、内聚性和咀嚼性降低,而黏附性增加。感官评价实验结果表明,PHGG添加量为3%时,馒头的综合感官评价得分最高。PHGG添加量在2%以上时,可以显著延缓馒头老化。PHGG可以降低馒头体外消化时的升糖指数。综合实验结果,PHGG添加量为3%时,馒头的品质最好。     

不同多糖对发酵空心挂面品质的影响

酵母发酵空心挂面是一种新型的工业化挂面产品,具有营养丰富、风味独特等特点,但尚存在干挂面韧性差和易断条、熟面条弹性不足等问题亟待解决。该文研究了瓜尔豆胶、黄原胶、海藻酸钠、羧甲基纤维素钠、魔芋粉5种常用多糖对发酵空心挂面微观结构、力学性质、蒸煮特性、质构品质和感官品质的影响。结果表明：与对照相比,单独添加0.1%瓜尔胶、海藻酸钠、羧甲基纤维素钠和魔芋粉时,挂面的蒸煮损失率从6.5%分别降低到5.8%、5.7%、5.3%和5.9%;添加0.5%黄原胶时,干挂面的面体更加致密,面条的最佳蒸煮时间增长了1.25 min,蒸煮损失减少了0.41%,干挂面的抗断裂强度和柔韧性、熟挂面的弹性、咀嚼性和拉断力分别提高了31.06%、49.79%、24.87%、61.62%和77.73%,此添加量下的面条的食用品质最佳,感官评价得分89分。5种多糖均显著改善了发酵空心挂面的柔韧性,及煮后挂面的弹性、咀嚼性和拉伸特性,其中黄原胶对发酵空心挂面的微观结构、力学性质、蒸煮特性、质构品质和感官品质改良效果较好。     

乳化剂、亲水胶体及谷朊粉对方便湿面品质的影响

为解决方便湿面因水分含量高易发生老化,硬度增加、弹性下降和口感变差等问题,采用三类添加物即乳化剂（单甘酯、硬脂酰乳酸钠、蔗糖酯）、亲水胶体（黄原胶、瓜尔胶、羧甲基纤维素钠）和谷朊粉对方便湿面面片的色泽、蒸煮品质及储藏期间的质构拉伸特性和水分分布的影响开展了研究。结果表明：蔗糖酯将面片的亮度从95.26显著提高到96.78;三类添加物均显著降低了蒸煮损失,其中添加0.20%硬脂酰乳酸钠使方便湿面的蒸煮损失从5.81%降低至3.00%;储藏期间,添加0.40%单甘酯可使方便湿面的硬度从4 787.44 g降低至2 904.95 g;三类添加物均显著提高了方便湿面的拉伸特性,其中添加0.20%蔗糖酯使方便湿面的拉伸力从17.94 g提高到24.13 g;从水分分布可以发现,乳化剂抑制了结合水的流动,增大了结合水的含量,减小了自由水的流失。综上所述,添加三类添加物均延缓了方便湿面在储藏期间淀粉的老化,使方便湿面的蒸煮损失降低、硬度减小和弹性增加,进而改善了方便湿面的品质,其中添加0.40%的单甘酯和0.30%瓜尔胶的效果较好。     

Faecal fermentation of partially hydrolyzed guar gum

Partially hydrolyzed guar gum (PHGG) remains undigested in the upper gastrointestinal tract, but is fermented by bacteria in the large intestine to stimulate short-chain fatty acids, particularly butyric acid. In this study, the bacterial composition in the in vitro faecal fermentation of PHGG was analyzed by real-time PCR to identify the bacteria contributing to the stimulation of butyric acid production. The production of short-chain fatty acids in a PHGG culture was compared with that in inulin and blank (no substrate) cultures. After the fermentation of the substrates by fresh human faeces, PHGG clearly promoted the production of butyric acid. The butyryl-CoA CoA-transferase gene copy number and the 16S rRNA gene copy number of the Roseburia/Eubacterium rectale group in the PHGG culture were significantly higher than those in the blank culture. These results indicated that Roseburia/E. rectale group bacteria would play an important role in the butyric acid production in vitro fermentation of PHGG.     

双酶改性制备玉米皮水溶性膳食纤维的工艺研究

以玉米皮超声提取天然水溶性膳食纤维后的副产物——不溶性玉米皮渣为试材,应用木聚糖酶和纤维素酶组合酶解制备水溶性膳食纤维,采用单因素和正交试验组合研究确立一套由水不溶性膳食纤维改性制备水溶性膳食纤维制备工艺。结果表明,最佳工艺参数为纤维素酶添加量40mg/g 底物、木聚糖酶添加量40mg/g 底物、料液比1:14(g/ml)、酶解时间90min,水溶性膳食纤维得率为5.96%。     

马铃薯膳食纤维物化特性分析及其对马铃薯热干面品质的影响

以马铃薯为原料,对膳食纤维进行提取制备,考察马铃薯膳食纤维的物化特性,并测定不同马铃薯膳食纤维添加量对马铃薯热干面品质的影响。结果表明,马铃薯膳食纤维中不溶性膳食纤维占48.74%;马铃薯膳食纤维的持水性为11.23?g/g,持油性为1.76?g/g,吸水膨胀性为6.65?mL/g,葡萄糖吸附能力为0.87?mmol/g,胆固醇吸附能力为2.04?mg/g;膳食纤维在一定程度上改善了马铃薯热干面的品质：随着膳食纤维添加量的增加,热干面的吸水率、蒸煮损失率呈不规律变化趋势;其剪切力及拉伸力整体上呈逐渐减小的变化趋势;膳食纤维能延缓面条中淀粉的分解,且增加面条中蛋白质的消化率。综上所述,膳食纤维的建议添加量为5%～12%。     

Sensory Optimization of Broken-Rice Based Snacks Fortified with Protein and Fiber

ABSTRACT:  A 3-component mixture experiment was used to optimize the formulation of broken-rice based snack fortified with protein and fiber based on consumer sensory acceptability. Soy protein isolate and guar gum were used as a good source of protein and fiber, respectively, according to DRV (daily reference value) based on a 2000-calorie diet. A consumer panel evaluated sensory acceptability of color, crispness, and flavor, and overall liking of 12 experimental broken-rice based snack formulations. Predicted models derived from the restricted nonintercept regression analysis were used to plot mixture response surfaces (MRS) of each sensory attribute. Areas within the MRS plots having predicted acceptability scores of at least 6.5 (on a 9-point hedonic scale) for color, crispness, flavor, and overall liking were selected to derive a predicted optimum formulation range. Flavor acceptability was a limiting factor in attaining the optimum formulation range, which consisted of 40% to 48% broken-rice flour, 8% to 16% guar gum, and 20% to 33% soy protein isolate. To verify the obtained predicted models, the formulation containing 48% broken-rice flour, 8% guar gum, and 20% soy protein isolate, which was located in the optimum area, was chosen to support our effort to utilize and add value to broken rice. Selected physicochemical measurements of the chosen optimized formulation were determined. One serving size (30 g) of the chosen optimized snack product provided 6.58 g protein and 3.80 g dietary fiber, which met the US FDA definition of a good source of protein and dietary fiber.     

酶法制备甘露低聚糖

利用枯草芽孢杆菌产生的碱性甘露聚糖酶,以魔芋、槐豆胶、瓜尔胶与田菁胶为原料,制备甘露低聚糖。比较了酶对底物水解反应动力学,对低聚糖制备过程中的水解液进行了还原糖测定,并通过质谱对最终酶解液组分进行分析。结果表明:魔芋与槐豆胶为甘露聚糖酶的最适水解底物,水解8h后,还原糖得率稳定,可作为甘露低聚糖生产的指导依据。酶解24h后,魔芋、槐豆胶、瓜尔豆胶及田菁胶的主要产物分别为二糖至九糖、五糖至十糖、二糖至十糖和二糖至十糖。利用酶法生产甘露低聚糖的方法具有水解过程简单、产物聚合度低、纯度高的优点。     

Controlling rheology and structure of sweet potato starch noodles with high broccoli powder content by hydrocolloids

Incorporating high volume fractions of broccoli powder in starch noodle dough has a major effect on its shear modulus, as a result of significant swelling of the broccoli particles. Several hydrocolloids with distinct water binding capacity (locust bean gum (LBG), guar gum, konjac glucomannan (KG), hydroxypropyl methylcellulose (HPMC) and xanthan gum), were added to systems with 4 and 20% (v/v dry based) broccoli particles, and the effect of this addition on dough rheology, mechanical properties and structure of cooked noodles was investigated. Hydrocolloids with low (LBG and guar gum) and intermediate (KG) water binding capacity had no significant effect on shear rheology of the dough. Adding hydrocolloids with high water binding capacity (HPMC and xanthan gum) decreased the shear modulus of dough with 20% broccoli particles significantly. CLSM analysis of cooked noodles showed that in samples containing xanthan gum there was also an inhibition of swelling of starch granules. Strength and stiffness of cooked noodles with 20% broccoli particles were higher for samples containing xanthan gum, than samples without xanthan gum. The cooking loss and swelling index of samples with added hydrocolloids were slightly lower than samples without hydrocolloids. Our results showed that hydrocolloids with high water binding capacity can be used to control the degree of swelling of vegetable particles and starch granules in starch noodle products, and thereby control both dough rheology and textural properties of the cooked noodles.     

纤维酶法制备可溶性麸皮膳食纤维工艺条件的优化

以小麦麸皮膳食纤维为原料,采用纤维素酶解法对小麦麸皮膳食纤维进行改性,制备可溶性麸皮膳食纤维。通过正交试验优化工艺条件,确定了纤维素酶解的最佳工艺条件:料液比1∶10、酶用量20 U/g、酶解p H 4.8、酶解温度60℃、酶解2 h,可溶性膳食纤维得率为12.67%。     

脱脂椰蓉可溶性膳食纤维制备工艺及单糖组成和理化特性分析

以脱脂椰蓉为原料,采用响应面分析法建立酶-化学法提取可溶性膳食纤维得率的二次多项数学模型,并验证数学模型的有效性。探讨酶添加量、酶解时间、碱添加量、碱解时间因素对可溶性膳食纤维得率的影响,优化提取工艺参数,确定最佳提取工艺参数为混合酶添加量0.5%、酶解时间50?min、碱液（NaOH溶液）质量分数5%、碱解时间40?min,在此条件下椰蓉粕可溶性膳食纤维得率达11.78%,持水性、持油性和膨胀性分别为3.8?g/g、5.2?g/g和3.1?mL/g。红外光谱分析发现,脱脂椰蓉可溶性膳食纤维处于缔合状态的氢键较多;高效液相色谱结果表明,可溶性膳食纤维含有9?种单糖,其中甘露糖、氨基半乳糖、半乳糖、阿拉伯糖含量较高,分别为537.21、40.38、39.48?mg/L和15.83?mg/L。     

复合膳食纤维素的结构及物性研究

采用大豆纤维素为基料,水溶性天然植物胶——瓜尔豆胶、果胶为辅料复合后,制备一种兼有水溶性和非水溶性双重特性的复合膳食纤维素。测定复合膳食纤雏素的粘度和表面张力,并对复合膳食纤维素体系进行扫描电镜观察后发现,大豆纤维素与瓜尔豆胶复合物的粘度和表面张力较两种单一成分均有明显提高,且复合物可调和成为以瓜尔豆胶溶胶为基体、大豆纤维素颗粒均匀镶嵌其间的稳定体系。大豆纤维素与果胶复合物的上述指标也有提高,但体系不稳定。     

Study on processing and quality improvement of frozen noodles

The processing method and quality improvement of frozen noodles were studied. To obtain the best mouthfeel and control the breakage during processing and cooking, noodles with a thickness of 1.1 mm and width of 3.4 mm were produced. The precooking method for raw noodles was steaming for 10 min and then boiling for 4 min before freezing to obtain the optimal characteristics for frozen noodles. Five frequently used food additives (guar gum, sodium stearyl lactate (SSL), cassava starch, glucose oxidase (GOD), and α-amylase) were used to improve the quality of frozen noodles. Cooking losses and sensory evaluation scores were adopted to optimize the formulation of frozen dough by a response surface methodology (RSM): guar gum 0.28%, SSL 0.44%, cassava starch 4.82%, GOD 0.003%, and α-amylase 0.04%. Frozen noodles had a more continuous microstructure and their storage quality was improved notably by this method.     

Influence of health based ingredient and its hydrocolloid blends on noodle processing

Blends were prepared with different levels of chickpea flour (CF) and durum semolina (0–60 %) and were utilized for understanding their influence on product quality. Proximate analysis and rheological characterization of blends were carried out. Noodles were developed and subjected to different physico-chemical, nutritional, cooking quality and sensory analysis, scanning electron microscopy (SEM). Optimized noodles on the basis of its sensory and cooking quality characteristics were improved with different hydrocolloids. Rheological studies revealed that with the increase in the CF content, Farinograph water absorption and dough stability decreased; simultaneously increase in dough development time. Maximum over pressure and curve configuration decreased with increase in CF. Based on the sensory and cooking loss of noodles 50 % formulation was improved with hydrocolloids. Noodles cooking loss reduced to 5.9 % with the addition of guar gum. Sensory scores for the noodles were above 8 in 15 cm scale. Colour value showed an increase in ‘b’ value, indicating increase in yellowness of samples. Texture of noodles became firm with the addition of CF. IVSD (In vitro starch digestibility) reduced from 71 to 29 %. There was a network like formation due to hydrocolloids was observed in SEM, which is the reason for slow release of glucose. Thus, can be used as substitution in noodles and can be included in the diet of malnutritious and diabetic population.     

Effects of nonprotein substances on protein hydrolysis and plastein formation

Effects of various naturally occurring nonprotein substances (carbohydrates, polysaccharides, fats and salts) on enzymatic hydrolysis of soy protein isolate and plastein formation from hydrolyzed soy protein were investigated. Relative extent of hydrolysis and plastein formation were measured as protein solubility in 10% trichloroacetic acid (TCA) since this method was found suitable for analysis of turbid, viscous and/or low protein samples. The presence of guar, xanthan, locust bean and arabic gums, arabinogalactan, unsaturated fatty acids (2%), salt mixture and xylan were found to enhance soy protein peptic hydrolysis at 0·5% enzyme/substrate; unsaturated fatty acids (1%) inhibited hydrolysis. At enzyme/substrate of 3·5%, hydrolysis was enhanced by xanthan gum, unsaturated fatty acids and sodium chloride but inhibited by gum karaya, salt mixture, starch, cellulose, and saturated fatty acids. Plastein synthesis was inhibited by xanthan, locust bean and guar gums but stimulated by arabinogalactan. Several nonprotein substances were found to interfere with the TCA solubility assay. Positive interference was noted for systems containing saturated and unsaturated fatty acids and magnesium, but negative interference was observed for systems containing guar gum, xanthan gum, calcium chloride and gum arabic.     

不同品种膳食纤维影响小鼠糖耐量结果的比较

本文选择多功能大豆纤维（MSF）、小麦纤维、纤维素、果胶和瓜儿胶等5种膳食纤维，对其影响小鼠葡萄糖耐量结果作了比较与分析。结果显示，1.0g/kg MSF、果胶或瓜儿胶可使葡萄糖耐量曲线变得尤为平缓，而同剂量纤维素和小麦纤维的效果并不显著。水溶性、粘性膳食纤维具有明显的稳定餐后血糖的作用，原因可能在于它能增加小肠内容物粘性，增加肠内非搅动层（unstirred layer）的厚度，并能使胃的排空速率降低，从而显著降低葡萄糖吸收速度。