Mathematical models for maximum improvement of in vitro protein digestibility of high dietary fibre cookies

Via substituting with wheat flour some high dietary fibre cookies were prepared (with 6, 12, 18 and 24%) from cereal industry by-products: corn bran (CB), rice bran (RB) and barley husk (BH). In vitro protein digestibility assay was used to examine the effect of substituting on protein digestibility. The applied nonlinear mathematical models indicated a higher determination coefficient between experimental and predicted data (R2 ≥ 0.999). A maximum in vitro protein digestibility (IVPD) of 88.4, 84.1, 85.2% was obtained when using optimum level substituting with wheat flour (7.9, 9.3 or 5.2%) in the CB, RB or BH respectively for producing cookies. The maximum improvement or minimum reducing IVPD by using fibre sources in producing cookies ranged from ?0.25% in RB to 4.9% in CB.     

Effects of alkaline,hydrogen peroxide-treated fibres on nutrient digestibility,blood sugar and lipid profile in rats

Three diets containing different sources of dietary fibre, wheat bran, faba bean testas and rice hulls, were tested to determine the effects of alkaline, hydrogen peroxide (AHP)-treated fibre at 10% substitution level of dextrose corn flour on apparent digestibility, faecal characteristics, and levels of plasma glucose and lipid profile in rats. A fourth non-fibrous diet was used as a control. The results showed that, although AHP treatment of fibres resulted in reduction of their weight after washing, it caused an increase in their water absorption and in their swollen volume when mixed with an excess of water (up to three fold) as in the case of wheat bran. Rats consuming diets containing dietary fibres showed a significant loss of body weight but no significant effects on heart weight or liver weight were found. Faeces of rats fed on dietary fibre diets showed an increase in weight and volume, which resulted in reduction of faecal density. The consumption of the treated fibre significantly reduced total cholesterol, plasma triglycerides and blood sugar; wheat bran was the most effective followed by rice hulls and faba bean testas. On the other hand, it effected an increase in the plasma content of high-density lipoprotein HDL-C but this increase was only significant in rats fed with wheat bran. Alkaline hydrogen peroxide-treated fibres showed a great improvement in their absorbency, making them equal to or even better than untreated fibre in lowering blood lipids and sugar levels, in addition to their excellent effect on the physiological function of the intestinal tract.     

Short-chain fatty acid content and pH in caecum of rats given various sources of carbohydrates

The caecal content of short-chain fatty acids (SCFA; acetic, propionic and butyric acid), caecal pH, fermentability and dry matter digestibility (DMD) were examined through balance experiments in rats fed 11 various indigestible carbohydrates. The following carbohydrate sources were incorporated into test diets: cellulose, oat husk, wheat bran, oat bran, pea fibre, linseed fibre, low methoxylated (LM)-pectin, guargum, β-glucans, neosugar and raffinose. The indigestible carbohydrates, except for those in wheat bran, oat husk and cellulose, were highly fermented, ie > 90%. Caecal pH varied between 5·6 and 7·8, with neosugar and raffinose causing the lowest pH and the fibre-free diet and the diet with oat husk the highest. The caecal pool sizes of SCFA were highest with raffinose, β-glucans, LM-pectin, guargum and linseed fibre (335-400 μmol) while pea fibre, wheat bran, oat bran and neosugar gave intermediate levels (137–227 μmol). The pool size with oat husk and cellulose was similar as with the basal diet (45–64 μmol). A high proportion of propionic acid was obtained with guargum and linseed fibre, whereas acetic acid was the predominant product in case of LM-pectin. On the other hand, linseed fibre gave a remarkably low proportion of butyric acid. The quantity fermented and caecal pH correlated well to the amount of SCFA with most materials (r = 0·96 and r = ?0·87, respectively), an exception was neosugar and in case of fermentability also oat bran. DMD values with most of the easily fermented carbohydrates were high (>96%). Exceptions were diets with β-glucans and oat bran which caused low DMD values, about 93%. It is concluded that indigestible carbohydrates may differ in ability to lower caecal pH and to form SCFA during fermentation.     

Changes in chemical composition during development of grass pea (Lathyrus sativus L.) seeds

The level of chemical components was determined in seeds of grass pea (Lathyrus sativus L.), cv. Krab, harvested at a dry matter content between 25.9 and 49.6 g/100 g of the raw material, and divided into five degrees of maturity. The results presented suggest that, in general, with an increasing maturity of seeds, the level of the following components increased if related to fresh matter: starch, dietary fibre, acids, total and protein nitrogen, total amino acids and sulphur amino acids, ash and its alkalinity, magnesium, calcium, total phosphorus and phytic phosphorus, and thiamine. The following components were reduced: vitamin C, riboflavin, carotenoids, beta-carotene, and chlorophylls. No such regularity could be found with respect to the accumulation of sugars, essential amino acids, and iron. By expressing the results in dry matter, increases were noted in starch, protein nitrogen, and thiamine. The content of sugars, total nitrogen, total amino acids, essential and sulphur amino acids, ash and its alkalinity, magnesium, phosphorus, vitamin C, riboflavin, carotenoids, beta-carotene, and chlorophylls were reduced while that of dietary fibre, iron, calcium, and phytic phosphorus varied.     

籽粒苋保健面包的研制(II)——籽粒苋对赖氨酸和膳食纤维的营养强化作用

以 5%、10 %、15%、2 0 %、2 5%籽粒苋粉代替小麦粉 ,制成籽粒苋保健面包。对这类面包中赖氨酸、膳食纤维含量进行分析 ,结果表明籽粒苋粉能明显提高赖氨酸和膳食纤维的含量 ,特别是能改善可溶性膳食纤维与不溶性膳食纤维的配比。与全麦粉面包相比 ,籽粒苋面包中蛋白质的提高率为 0 .58%～ 6 .91% ,赖氨酸含量提高率为 13.50 %～ 56 .57% ,总膳食纤维提高 8.2 6 %～ 39.4 5% ,不溶性膳食纤维提高 7.91%～33.33% ,可溶性膳食纤维提高 9.76 %～ 6 5.85% ;而脂肪的含量则随籽粒苋粉的增加而减少。由于籽粒苋对赖氨酸和膳食纤维具有强化作用 ,使籽粒苋保健面包可以作为高脂血症、糖尿病和肥胖人群的理想食品     

Contents of dietary fibre components and their relation to associated bioactive components in whole grain wheat samples from the HEALTHGRAIN diversity screen

A large and diverse material collection of whole grain wheat samples (n = 129) was analysed for total dietary fibre (TDF) content and composition, including fructan (11.5–15.5%). Correlations between the dietary fibre components, associated bioactive components (e.g. tocols, sterols, phenolic acids and folates) and agronomic properties previously determined on the same samples were found with multivariate analysis (PCA). Samples from the same countries had similar characteristics. The first PC described variation in components concentrated in the starchy endosperm (e.g. starch, β-glucan and fructan) and the dietary fibre components concentrated in the bran (e.g. TDF, arabinoxylan and cellulose). The second PC described the variation in kernel weight and other bran components such as alkylresorcinols, tocols and sterols. Interestingly, there was no correlation among these different groups of bran components, which reflected their concentration in different bran tissues. The results are of importance for plant breeders who wish to develop varieties with health-promoting effects.     

Rapeseed meal. II. Chemical composition and biological quality of the protein

The chemical composition (moisture, ash, protein, amino acids, ether extract, crude fibre, Ca, P, Fe, thioglucosides, isothiocyanates and oxazolidinethiones) and biological quality (net protein utilisation, available lysine and digestibility) were investigated in 12 samples of presscake meal of rapeseed (Brassica napus) collected from local factories. Crude fibre and mineral contents were comparatively high. Thioglucosides and their hydrolysis products (isothiocyanates and oxazolidinethiones, which are toxic) were found in high concentrations. All samples showed a high protein content and their amino acid patterns corresponded to a good-quality protein with a score of 80, and an adequate level of available lysine. Nevertheless, the biological quality measured as net protein utilisation and digestibility gave low values, which could be explained on the basis of the presence of the toxic factors and the high level of crude fibre, respectively.     

稻谷加工主要副产物的营养及功能性成分分析

为探明稻谷加工主要副产物米糠、米糠粕和白米糠的成分差异,对三者的营养成分及其功能性成分进行了测定和分析。结果表明：米糠、米糠粕和白米糠的碳水化合物含量均在50%以上,白米糠的淀粉含量最高,米糠粕中膳食纤维含量最高。米糠富含油脂和维生素E,可作为浸油的原料。白米糠富含淀粉,可作为微生物发酵原料或酿造原料。米糠粕富含优质蛋白质和膳食纤维,与白米糠和米糠相比,微生物感染小、有利于保藏。此外,米糠、白米糠和米糠粕中的人体必需氨基酸含量占氨基酸总量的45%左右,是必需氨基酸的良好来源。     

Effect of insoluble dietary fibre addition on technological,sensory, and structural properties of durum wheat spaghetti

Insoluble fibres are important in human health and disease prevention and can be incorporated into food. High fibre pasta prepared with bran is typically inferior quality compared to durum pasta. This study compared spaghetti prepared from durum semolina substituted with various amounts of either durum bran or germ (pollard) dried at high temperature. Pasta was evaluated for cooking properties, texture, sensory, fibre content, antioxidant status (AO) and in vitro starch digestibility to determine the dose producing acceptable quality. Pollard at 10% substitution had minimal impact on quality with higher AO and fibre. Above 30%, pasta had undesirable colour, sensory properties and higher starch digestion. Although bran substituted pasta had undesirable sensory and technological properties, especially at 30% incorporation, it does provide more dietary fibre and antioxidants than regular pasta and does not affect starch digestibility. Interestingly, a significant amount of AO was retained in the cooked pasta. The study illustrates the value of structural analysis to explain observed technological properties of the product with fibre inclusion.     

Effect of micronised oat bran by ultrafine grinding on dietary fibre,texture and rheological characteristic of soft cheese

The purpose of this research was to study the effect of micronised oat bran on dietary fibre, textural and rheological of soft cheese. The soft cheese was processed by using the different particle size oat bran as fibre supplement, and its dietary fibre content, rheological and textural properties were determined. The results show that the micronised oat bran with 5–30 μm particle size was prepared by ultrafine grinding and passed through 60–400 mesh sieves. The soluble dietary fibre content in micronised oat bran soft cheeses was higher than that of the control (untreated oat bran soft cheeses; P < 0.05), with a maximum of 2.65 g per 100 g cheeses when oat bran was ultrafine crushed and passed through 300 mesh sieves, while the content of insoluble dietary fibre was lower than that of the control (P < 0.05). The micronised oat bran soft cheese in fermentation is a typical non-newtonian fluid. G′, G″ and apparent viscosity of soft cheeses were increased with the reduction of oat bran particle size. The chewiness and springiness of micronised soft cheeses were increased with the reduction of oat bran particle size, and were higher than that of the control (P < 0.05). The hardness and cohesiveness of micronised soft cheese were decreased with the reduction of oat bran particle size, the hardness was lower, but the cohesiveness of micronised soft cheese was higher than that of the control (P < 0.05). The 1% micronised oat bran can obtain better processing characteristics and overall acceptability for cheese products.     

Does a mix of plant-based dietary fibre affect milk protein true digestibility? An in-vivo study

Milk protein is easily digestible. However, some plant-based dietary fibres (DF) could impact protein bioavailability. The effect of DF fortification on the true protein digestibility (TPD) of milk was evaluated following the rat balance method. Four groups of rats were fed four different diets. Three diets comprised milk protein as a source of protein along with either DF Blend I (a mix of psyllium husk, oat fibre, microcrystalline cellulose and inulin) or Blend II (psyllium husk, oat bran, wheat fibre and inulin) or cellulose (as control). The fourth group was nitrogen-free with cellulose (5%). The TPD of milk remained statistically unaffected (ANOVA, P > 0.05), indicating that DF blends are suitable for milk fortification.     

大麦在发芽过程中营养物质的变化及其营养评价

通过测定发芽大麦中的蛋白质、脂肪、淀粉、氨基酸、还原糖、β-葡聚糖、总膳食纤维、可溶性膳食纤维、不溶性膳食纤维、VB1和VB2的含量,研究发芽时间对大麦营养价值的影响。结果表明：发芽过程中,总干物质有一部分降解,蛋白质、淀粉和脂肪均呈下降趋势;但可溶性低分子糖类、含氮物质和维生素含量有很大提高,其中还原糖含量上升2.78%～14.36%,总氨基酸含量增加了8.15%,且7种必需氨基酸含量均逐渐增加,赖氨酸增幅最大（32%）。与未发芽大麦相比,VB2含量增长了17.8倍;VB1含量变化不大;β-葡聚糖呈下降趋势;可溶性膳食纤维增加。发芽过程中,必需氨基酸/总氨基酸值和必需氨基酸指数增加,必需氨基酸组成模式更加符合联合国粮食及农业组织/世界卫生组织联合食品标准计划,第一限制氨基酸由原来的赖氨酸转变为蛋氨酸+胱氨酸。结论：发芽在一定程度上提高了大麦的营养价值,但对其在利用β-葡聚糖相关功能特性方面有一定的限制。     

Biochemical properties of type I sourdough affected by wheat bran dietary fibre during fermentation

The supplementation of dietary fibre in sourdough is beneficial to increase the nutritional quality of fermented foods. The influence of different wheat bran dietary fibre (WBDF) levels (0%, 3%, 6%, 9%, and 12%) on the biochemical characteristics of sourdough during fermentation was investigated. This study showed that WBDF was slightly resistant to the reduced pH caused by the initial fermentation of sourdough dough. After 6 h of fermentation, whether or not it contained WBDF, the dough’s amylase activity was relatively stable (P > 0.05). However, in the samples containing WBDF, it took longer for the amylase activity to increase from 200 to 300 U g⁻¹. The content of free amino acids in the dough showed a tendency to first decrease and then increase with the metabolic activity of microorganisms, and WBDF could accelerate this rate. This study also provided evidence that insoluble dietary fibre may stimulate the growth and reproduction of lactic acid bacteria.     

两种制粉方式对紫粒小麦营养功能成分的影响

采用机械分层碾磨和石磨制粉2种加工方式,对"贵紫4号"紫粒小麦加工的面粉和麸皮进行淀粉、粗蛋白、脂肪、粗纤维、维生素、矿物质、氨基酸、总酚、花青素等营养功能成分的对比分析。结果表明,机械分层碾磨和石磨制粉,对面粉和麸皮的营养功能成分影响显著(P<0.05),机械一等粉和机械麸皮的常规营养成分、钙、铁、锌和维生素含量分别高于石磨面粉和石磨麸皮,而石磨面粉的硒含量比机械一等粉高113.90%,石磨制粉的花青素含量比机械制粉高4.90%,说明2种加工方式各有优缺。从氨基酸组成看,"贵紫4号"紫粒小麦的AAS评分高于普通小麦9.70%,且麸皮中的赖氨酸评分大于1(变为非限制性氨基酸),花青素含量达2 904.93 mg/kg,是麸皮入粉进行全麦加工的优质原料。     

Nutritional and sensory properties of a maize‐based snack food (kokoro) supplemented with treated Distillers’ spent grain (DSG)

The effect of treated Distillers’ spent grain (DSG) supplementation on the nutritional and sensory properties of kokoro, a maize‐based snack, was investigated. Treated DSG was used to replace 5%, 10%, 15%, 20%, 25%, 30% and 35% of maize flour. Mean water absorption capacity of DSG was 291%, swelling capacity 2.27 bulk density was 58%, oil absorption capacity 216, protein content of 27% and a total dietary fibre content 24.2%. The swelling, water and oil absorption capacities of the flour blends increased while bulk density decreased significantly. The ash, fat, protein, insoluble and total dietary fibre and total nonessential and essential amino acids contents of the flour blends increased with DSG inclusion. Processing the flour blends to kokoro slightly increased the ash, fat and protein contents, while the total nonessential and essential amino acids, total sugar and total dietary fibre decreased. The addition of DSG increased the lysine and tryptophan contents of kokoro. Although the sensory evaluation results indicate that kokoro with 5%, 10% and 15% DSG were well accepted and compared favourably with those made from whole maize for overall acceptability, it was observed that generally, there is a consumer dislike of the new product as the amount of DSG added increased.     

乳酸菌发酵香菇柄主要营养成分的变化

目的研究香菇柄经过乳酸菌发酵后主要营养成分的变化。方法采用乳酸菌为菌种发酵香菇柄,与未添加乳酸菌的香菇柄作比较,测定发酵前后主要营养成分的含量,并用高效液相色谱法检测膳食纤维的单糖组成。结果与发酵前相比,香菇柄经过发酵后总糖、不溶性膳食纤维含量下降,总膳食纤维、蛋白质的含量上升,尤其是可溶性膳食纤维和总酸含量显著上升(P0.05),分别提高了2.13倍和2.71倍;可溶性膳食纤维的单糖组成种类无变化,其中,葡萄糖、木糖、甘露糖含量增加,半乳糖含量减少;水解氨基酸的种类无变化,总量略有提高,除赖氨酸外,各水解氨基酸经过发酵后含量均未有减少;游离氨基酸总量减少了31.72%,但部分游离氨基酸含量有所增加,呈味氨基酸组成发生变化,酸味氨基酸、鲜味氨基酸、芳香味氨基酸含量均有提高。结论本研究为开发乳酸菌发酵香菇柄的香菇制品提供理论依据。     

Impact of cell wall‐degrading enzymes on water‐holding capacity and solubility of dietary fibre in rye and wheat bran

BACKGROUND: Rye and wheat bran were treated with several xylanases and endoglucanases, and the effects on physicochemical properties such as solubility, viscosity, water‐holding capacity and particle size as well as the chemical composition of the soluble and insoluble fractions of the bran were studied. A large number of enzymes with well‐defined activities were used. This enabled a comparison between enzymes of different origins and with different activities as well as a comparison between the effects of the enzymes on rye and wheat bran. RESULTS: The xylanases derived from Bacillus subtilis were the most effective in solubilising dietary fibre from wheat and rye bran. There was a tendency for a higher degree of degradation of the soluble or solubilised dietary fibre in rye bran than in wheat bran when treated with most of the enzymes. CONCLUSION: None of the enzymes increased the water‐holding capacity of the bran or the viscosity of the aqueous phase. The content of insoluble material decreased as the dietary fibre was solubilised by the enzymes. The amount of material that may form a network to retain water in the system was thereby decreased. © 2012 Society of Chemical Industry     

Loss of selected water-insoluble polysaccharides and component neutral sugars from swede (Brassica napus (cv. danestone)) and cereal bran measured during digestion in the pig caecum

Sources of dietary fibre with a high pentose sugar content have been shown to have the greatest effect in promoting faecal bulking, though no underlying reason for this has been found. Pentose-containing polysaccharides in dietary fibre are, in isolation, as degradable as other polysaccharides, though their known association with lignin could be important in helping to maintain the structural integrity and hence the bulking ability of a fibre source. Using a modified nylon bag technique, the potential digestibility of fibre prepared from a source rich in pentose sugars (cereal bran) and a source poor in pentose sugars (Swede; Brassica napus, cv. Danestone) was estimated in the pig caecum. Swede fibre was effectively completely degraded (within 18 h) but in bran 100% digestion was not achieved even with extended incubation. Rates of fibre component loss, estimated from material recovered from the nylon bags, showed that different fibre components were degraded at different rates and that the rate of degradation was not always linear. In swede xylose was less readily lost than other fibre components and the rate was non-linear whilst in bran xylose was preferentially lost and at a linear rate. In bran arabinose was less readily lost. The results showed that the bulking effects of fibre sources with a high pentose sugar content were unlikely to be due solely to pentose content. Differences in rates of digestion suggested that different linkage groups contained within a component may be able to modify the degree of fibre digestion, most probably by the linkage of specific pentosans to lignin.     

Rice bran proteins: Properties and food uses

Rice bran, a good source of protein and fat, is at present underutilized as a food material. The potential of producing rice bran at the global level is 27.3 million t. The presence of enzyme lipase in rice bran causes rapid deterioration of oil to free fatty acids and glycerol. Various stabilization techniques involving heat treatment, low‐temperature storage, chemical treatment, control of relative humidity during storage, and simultaneous milling and extraction were evolved to inactivate lipase. Multiple forms of rice bran lipase have been identified. Fractional classification of proteins reveals a high percentage of albumins and globulins. Proteins can be extracted from full‐fat or defatted rice bran by alkaline extraction and acid or heat precipitation. Extraction procedures influence the protein content of concentrates, which ranged from 19.4 to 76.1% in concentrates from full‐fat rice bran and 17.5 to 85.0% in concentrates from defatted rice bran. The PER of rice bran ranges from 1.59 to 2.04 and that of protein concentrates from 1.99 to 2.19. Available lysine contents of protein concentrates ranged from 54 to 58.8%. The essential amino acid profiles of protein concentrates indicate that threonine and isoleucine are limiting amino acids. Various functional properties of rice bran protein concentrates have also been investigated that are known to be influenced by drying technique and stabilization treatment of rice bran. Rice bran has been used in food as full‐fat rice bran, defatted rice bran, and in the form of rice bran oil and protein concentrates. Full‐fat and defatted rice bran have been used in bakery products, breakfast cereals, wafers, as a protein supplement, binder ingredients for meats and sausages, and as a beverage base. Incorporation of protein concentrates have been studied in bread, beverages, confections, and weaning foods.