Some functional properties of oat bran protein concentrate modified by trypsin

Oat bran protein concentrate (OBPC) was prepared from oat bran, and hydrolyzed using trypsin. Protein hydrolysates of three different degrees of hydrolysis (4.1%, 6.4% and 8.3% respectively) were obtained. SDS-PAGE analysis demonstrated that oat globulin was the major protein component in OBPC. After trypsin treatment, acidic polypeptides were partly degraded into large peptides (M_r = 29,000–33,000) and small peptides (M_r < 20,000); however, basic polypeptides were almost intact. The functional properties of the resulting products were compared with those of control OBPC. Marked changes in the protein functionality were caused by proteolysis. The solubility, water-holding capacity, emulsifying activity and foaming ability of the hydrolysates gradually increased with the increase in DH. However, the oil-holding capacity, emulsifying stability and foaming stability of the hydrolysates reduced to a certain extent.     

Optimization of Viscozyme L-assisted extraction of oat bran protein using response surface methodology

The study investigated enzymatic pretreatment of oat bran, using Viscozyme L to enhance protein extraction. Response surface methodology (RSM) was used to study the effects of pretreatment variables of Viscozyme L concentration (6–30 FBG), pH (3.0–5.0), incubation time (0.5–2.5 h) and temperature (35–55 °C) on protein extraction from oat bran. The results indicated that the generated regression model represented the relationship between the independent variables and the responses. Protein extraction from oat bran was mainly affected by pH and incubation temperature. From the RSM-generated model, the optimum conditions of enzymatic pretreatment were identified as Viscozyme L concentration 30 FBG/10 g of oat bran, pH 4.6, incubation time 2.8 h and temperature 44 °C. Under the optimum conditions, the predicted protein extracted from oat bran was 55.7%, whereas, the experimental extracted protein was 56.2%. The RSM-predicted and experimental extracted proteins were not significantly different from each other. The enzymatic pretreatment method under the optimum conditions extracted significantly more protein (56.2%) than did the alkaline (pH 9.5) method (14.76%). Viscozyme L pretreatment of oat bran improved protein extraction.     

米糠油制备甘二酯工艺优化

采用响应面法优化米糠油制备甘二酯的工艺条件。在反应温度、反应时间、固定化脂肪酶添加量及反应物质量比4个单因素试验的基础上,通过四元二次回归正交旋转组合设计结构矩阵的建立,构建以甘二酯产率为响应值的二次回归模型并进行分析。结果表明:当温度为26℃、反应时间为10h、固定化脂肪酶添加量为8.5%及反应物质量比为14∶1时,甘二酯产率理论为60.36%,实际为58.31%,相对误差为3.4%。     

Role of carbohydrases on the release of reducing sugar, total phenolics and on antioxidant properties of oat bran

Aqueous solutions of medium oat bran flour were treated with four carbohydrases viscozyme, celluclast, alpha-amylase, and amyloglucosidase, and then extracted with equal volume of methanol. The resulting extracts were examined for their reducing sugar content, total phenolic content (TPC), oxygen radical scavenging absorbance capacity (ORAC), hydroxyl radical scavenging effect, superoxide scavenging activity, and ferrous ion chelating potential. The amount of reducing sugar increased form 2.0% in the control sample to 21.4% in the sample treated with four fungal beta-glucanase units/g of bran. The increase in reducing sugar was also associated with subsequent increase of other extractable compounds. The total phenolic content as measured by Folin-Ciocalteu’s method ranged from 0.50 to 4.80 mg of gallic acid equivalents/g of bran, whereas the ORAC values were 14.4-25.4 μM of Trolox equivalents/g of bran. All the samples treated with carbohydrases had higher TPC content and higher ORAC values than the control sample (no enzyme treatment). In the hydroxyl radical scavenging assay, except for the alpha-amylase treated sample, all other samples demonstrated a greater inhibition power than the control. These results indicated that pre-treatment of oat bran with cell wall degrading enzymes (i.e. carbohydrases) is a way to increase the amount of extracted phenols as well as the antioxidant properties of oat bran samples.     

Optimization of the enzymatic pretreatment in oat bran protein extraction by particle swarm optimization algorithms for response surface modeling

Enzymatic pretreatments of oat bran, using viscozyme L to enhance protein extraction, were investigated. To obtain the best possible combination of enzymatic pretreatment variables including viscozyme L concentration, incubation time, pH and incubation temperature for maximum protein extraction, modern optimization techniques were employed. The optimization procedure included two stages: creating a response surface model through regression on experimental data and then optimizing the model by Particle Swarm Optimization (PSO) algorithms. The optimum conditions of enzymatic pretreatment were: viscozyme L concentration, 30 FBG/10 g of oat bran; incubation time, 2.8 h; pH 4.6; and incubation temperature, 44 °C. Under such conditions, the predicted maximum protein extracted was 55.69%, which coincided with the experimental values. These results indicated that enzymatic pretreatment can improve protein extraction significantly and PSO algorithms were efficient approaches for optimizing the conditions of enzymatic pretreatment of oat bran.     

酶法制备燕麦麸蛋白ACE抑制肽的研究

采用碱溶酸沉法制备了燕麦麸蛋白,并利用7种商业化蛋白酶对其进行酶解以考察生产ACE抑制肽的效果,结果表明Alcalase为最适用酶。优化了Alcalase水解燕麦麸蛋白的工艺条件,在[S]=5.0%,E/S=1.33%,pH7.5,温度60℃条件下酶解90min,酶解产物的ACE抑制活性最强(IC50=0.291mg/mL),此时水解度为11.0%,产物的相对分子质量主要集中在880Da以下。     

Maize bran/oat flour extruded breakfast cereal: A novel source of complex polysaccharides and an antioxidant

A maize bran/oat flour extruded breakfast cereal was developed as a novel source of an antioxidant and complex polysaccharides. Six levels of maize bran/oat flour were formulated (0, 10, 20, 30, 40 and 50%, w/w). The breakfast cereal containing 30% maize bran was the most accepted by consumers. A 100 g serving of this cereal formulation provides 0.2 g of ferulic acid, and 8 g of complex polysaccharides, which includes 1.2 g of β-glucans and 6.8 g of arabinoxylans. This cereal breakfast could be an alternative to maize bran, which is a by-product scarcely used for human consumption.     

复合蛋白酶(Protamex)提取米糠蛋白条件优化

以米糠为原料,利用复合蛋白酶(Protamex)提取蛋白。在提取过程中,以蛋白收率为指标,确定提取时间、提取温度、pH值和酶添加量4个因素对脱脂米糠蛋白收率的影响。经试验确定出复合蛋白酶法提取米糠蛋白的最佳条件为:提取时间3h、温度45℃、pH值6.0、酶添加量为400U/g,水解度为2.33%,经测定所用的米糠原料成分为蛋白质14.83%、脂肪22.94%、纤维素24.55%、水分8.84%。     

A novel process for microencapsulation of fish oil with barley protein

This research represents the first scientific publication reporting barley protein as a wall material to encapsulate fish oil. Solid microcapsules were able to form in aqueous solution by pre-emulsifying barley proteins with a homogenizer followed a microfluidizer system. No organic solvent or cross-linking reagents were used in the preparation process. The wet status microcapsules were converted into free-flowing powder (dry status microcapsules) by a spray-drying process. The optimum microcapsule preparation conditions were 15% protein, oil/protein ratio = 1.0, and an inlet temperature of 150 °C. These microcapsules exhibited high encapsulation efficiency (EE: 92.9–100.2%), loading efficiency (LE: 46.5–50.1%) and low moisture content (0.75–0.90%). The oxidative stability of microencapsulated fish oil was tested at both dry status and in aqueous solutions (pH 7.0 and pH 2.0) in an accelerated storage test (40 °C, 8 weeks). These barley protein microcapsules possessed a strong ability to protect fish oil against oxidation, making them ideally suited for use in liquid/semi-liquid food systems. Food formulation tests confirmed their successful application in milk and yogurt for their respective shelf lives.     

Optimization of emulsification conditions with rice bran concentrates for the preliminary formulation of potential vegan dressings and their characterization

A fraction of rice bran (RB), generated during the brown rice polishing, is utilized to extract oil, resulting in defatted RB (DRB). The aim of this study was to optimize the emulsification conditions to enhance the value of this byproduct by formulating potential vegan dressings and characterizing them. Enzymatic hydrolysis of the starch present in DRB yields the DRB concentrate (DRBC). A central composite design was applied and the results were analyzed using response surface methodology to select optimal conditions for an oil-in-water emulsion formula. Two formulations were chosen: one corresponds to the optimal conditions, with 26.5% of oil and 73.5% of DRBC dispersion ( e_optimal ), and the other one with 21.7% of oil and 78.3% of dispersion ( e_ED8 ). The e_optimal formulation exhibited significantly lower mean De Brouckere diameter (D_4,3) value and higher viscosity when compared with e_ED8 . For both emulsions, the particle size distribution and D_4,3 remained unchanged during storage, whereas viscosity decreased, and backscattering (BS) increased. Initially, both emulsions exhibited solid viscoelastic behavior, which was partially lost during quiescent storage. The increase in BS was attributed to particle disaggregation, ultimately leading to the aforementioned change in rheological behavior. In conclusion, although the designed emulsions underwent microstructural changes, they were stable against gravitational separation. To improve stability during quiescent storage, it is suggested to incorporate a thickening agent. Hence, it is propose to procced with the development of a vegan dressing based on the e_optimal emulsion, as it exhibits superior physicochemical properties.     

超声波辅助法提取黑色小麦麸皮花色苷工艺优化

该文采用超声波辅助有机溶剂法对黑色小麦麸皮中花色苷进行提取,研究提取溶剂、p H、料液比、超声温度及超声时间对花色苷提取量的影响。在单因素基础上选取参数范围进行正交实验优化提取条件,确定最佳提取工艺:70%盐酸甲醇溶液(p H 1.0)作为提取溶液,料液比1∶15,超声温度60℃,超声时间80 min。在此优化条件下,花色苷的提取量为700.35 mg/kg。     

复合菌发酵苦荞麸皮馒头的工艺优化

选取从酸面团筛选的酵母YCY5-2,ZKY7-1及乳酸菌YCL7-3,ZKL10-4进行组合发酵苦荞麸皮馒头,以馒头黄酮含量和感官评定分数作为指标,筛选出发酵苦荞麸皮馒头的最适菌种组合。实验采用响应面法对菌株比例,菌株接种量,发酵时间和醒发时间进行了优化。结果表明:最佳组合菌种为YCY5-2和ZKL10-4,苦荞麸皮添加量为20%,最佳工艺条件为YCY5-2∶ZKL10-4=2∶1,菌种添加量为3%,发酵时间为5 h、醒发时间40 min。此条件下苦荞麸皮馒头黄酮含量为（211.33±1.34）mg Rutin/100 g,感官评分为（82.2±2.30）。与安琪酵母发酵的苦荞麸皮馒头的黄酮含量（（189.70±3.66 mg）Rutin/100 g）,感官评价（77.1±1.4）及质构相比可知,复合菌馒头的功能和品质均比安琪酵母的好。结论:复合菌发酵的苦荞麸皮馒头具有开发利用的价值。      

Optimization of ingredients and baking process for improved wholemeal oat bread quality

Baking technology for tasty bread with high wholemeal oat content and good texture was developed. Bread was baked with a straight baking process using whole grain oat (51/100 g flour) and white wheat (49/100 g four). The effects of gluten and water content, dough mixing time, proofing temperature and time, and baking conditions on bread quality were investigated using response surface methodology with a central composite design. Response variables measured were specific volume, instrumental crumb hardness, and sensory texture, mouthfeel, and flavour. The concentration and molecular weight distribution of β-glucan were analysed both from the flours and the bread. Light microscopy was used to locate β-glucan in the bread. Proofing conditions, gluten, and water content had a major effect on specific volume and hardness of the oat bread. The sensory crumb properties were mainly affected by ingredients, whereas processing conditions exhibited their main effects on crust properties and richness of the crumb flavour. β-glucan content of oat bread was 1.3/100 g bread. The proportion of the highest molecular weight fraction of β-glucan was decreased as compared with the original β-glucan content of oat/wheat flour. A great part of β-glucan in bread was located in the large bran pieces.     

Optimization of enzymatic degumming process for rice bran oil using response surface methodology

Response surface methodology was used to determine the optimum processing conditions for enzymatic degumming of rice bran oil. Reaction time, enzyme dosage, level of water added and temperature were the factors investigated with respect to phosphorus and free fatty acids contents. A D-optimal design, with four variables and two response functions, was employed to study the effect of the individual variables on the response functions. For each response, second-order polynomial models were developed using multiple linear regression analysis. Applying desirability function method, optimum operating conditions were found to be reaction time of 4.07 h, enzyme dosage of 50 mg/kg, added water of 1.5 ml/100 g and temperature of 49.2 °C. At this optimum point, phosphorous and free fatty acids contents of degummed oil were found to be 8.86 mg/kg and 2.01 g/100 g as oleic acid, respectively.     

脱臭过程中保留米糠油中植物甾醇的工艺优化

采用氮气蒸馏法进行米糠油的脱臭,研究了脱臭温度、脱臭时间以及氮气流速对脱臭米糠油中植物甾醇含量的影响。结果表明,在保证得到高品质米糠油的前提下,最大程度保留脱臭油中植物甾醇的优化工艺条件为:脱臭温度260℃,脱臭时间120 min,氮气流速0.12 m3/h。在最优工艺条件下,植物甾醇保留率(相对于脱色油)为83.38%,米糠油酸值(KOH)为0.25 mg/g,精炼率为93.01%。同时发现,脱臭前后米糠油中植物甾醇的主要组成成分没有变化,均为豆甾醇、菜油甾醇和β-谷甾醇。     

高酸值米糠毛油碱炼脱酸工艺及条件的优化研究

以高酸值米糠毛油为原料,采用两次碱炼脱酸工艺,以碱炼得率、脱色率、谷维素损失率、甾醇损失率为考察指标,研究碱液质量分数对两次碱炼脱酸工艺中一次、二次碱炼效果的影响,并与一次碱炼脱酸工艺进行比较。结果表明:随碱液质量分数的增大,两次碱炼脱酸工艺中的一次、二次碱炼的碱炼得率变化不大,一次碱炼脱色率在14.24%时最大,二次碱炼脱色率呈起伏变化;两次碱炼脱酸工艺中二次碱炼时采用较低的碱液质量分数有利于甾醇和谷维素的保留;与一次碱炼脱酸工艺相比,两次碱炼脱酸工艺在相同碱液质量分数条件下,油脂碱炼得率平均提高4.89个百分点,谷维素损失率平均降低5.87个百分点;在碱液质量分数较低(8.07%~14.24%)时,脱色率平均提高9.25个百分点,甾醇损失率平均降低12.64个百分点。对于高酸值米糠毛油,采用两次碱炼脱酸工艺和质量分数为14.24%以下的碱液,对提高碱炼得率和脱色率以及减少谷维素和甾醇的损失都具有明显优势。     

高温-复合酶法改性小米糠膳食纤维工艺优化及结构与功能分析

本文采用高温-复合酶法改性脱脂小米糠膳食纤维（DF）并优化工艺;通过扫描电镜（SEM）、X-射线衍射（XRD）、傅里叶红外图谱（FT-IR）及吸附性能等分析改性膳食纤维的结构及功能性质。结果表明,高温-复合酶法改性小米糠膳食纤维的最佳工艺条件为：复合酶比例（木聚糖酶∶纤维素酶）为2：1、复合酶用量2%、 酶解温度50 ℃、酶解时间1.50 h,在此条件下改性后小米糠可溶性膳食纤维（SDF）得率达到17.27±1.57%;SEM表明改性后样品形态均发生改变,呈现多孔隙网络结构,毛细管吸附作用增强,XRD表明DF改性后纤维晶型保持不变,仍为纤维素Ⅰ型,结晶度增大,FT-IR显示改性后吸收峰的峰型、位置均未有明显改变;改性后葡萄糖、胆固醇的吸收能力分别增加23.05%和0.813%（pH 2）、3.195%（pH 7）且具有显著性差异,同时α-淀粉酶的抑制率增加了13.47%。综上所述,高温-复合酶法可以有效改性膳食纤维,提高其结构和功能特性。     

米糠大豆酸奶发酵条件的优化

采用单因素实验和正交实验设计,对米糠大豆酸奶进行了研究,筛选出最佳工艺条件为:米糠与黄豆浆质量比为1/2,稳定剂为1:1海藻酸钠和琼脂,其添加量为米糠酶解液质量的0.13%,发酵温度为45℃,发酵时间为5 h。在此条件下,感官评定值为93.83分,乳酸含量是58.28 μg/mL,蛋白质含量为3.67 g/100 g。该植物性食品含有米糠以及大豆的重要天然营养成分,可以发挥米糠、大豆和酸奶的多种营养保健作用,为米糠大豆的开发利用提供了新的途径,也提高了米糠大豆的经济效用。     

Nanofiltration process for the nutritional enrichment and refining of rice bran oil

Crude rice bran is a natural source of γ-oryzanol, a nutritionally valuable phytochemical with antioxidant properties. In the present paper the refining and γ-oryzanol enrichment of rice bran oil was investigated through solvent extraction optimization and nanofiltration processing. Several solvent resistant nanofiltration membranes were screened and successfully applied in a two step membrane cascade with fluxes between 39 and 53 L m⁻² h⁻¹. A first membrane stage operation provided the separation between glycerides and γ-oryzanol, promoting the oil enrichment in this phytochemical. In the second membrane stage the oil could be refined to acceptable consumption levels (FFA < 0.20 wt.%) and its γ-oryzanol content was further enhanced. Overall, the integrated process provided a RBO γ-oryzanol enrichment from 0.95 to 4.1 wt.% in oil, which corresponded to more than a two fold increase in the oil’s antioxidant capacity. These results demonstrate the potential of organic solvent nanofiltration as a technology to enrich and refine oil based products.     

Effect of buckwheat flour and oat bran on growth and cell viability of the probiotic strains Lactobacillus rhamnosus IMC 501®, Lactobacillus paracasei IMC 502® and their combination SYNBIO®, in synbiotic fermented milk

Fermented foods have a great significance since they provide and preserve large quantities of nutritious foods in a wide diversity of flavors, aromas and texture, which enrich the human diet. Originally fermented milks were developed as a means of preserving nutrients and are the most representatives of the category. The first aim of this study was to screen the effect of buckwheat flour and oat bran as prebiotics on the production of probiotic fiber-enriched fermented milks, by investigating the kinetics of acidification of buckwheat flour- and oat bran-supplemented milk fermented by Lactobacillus rhamnosus IMC 501®, Lactobacillus paracasei IMC 502® and their 1:1 combination named SYNBIO®. The probiotic strains viability, pH and sensory characteristics of the fermented fiber-enriched milk products, stored at 4 °C for 28 days were also monitored. The results showed that supplementation of whole milk with the tested probiotic strains and the two vegetable substrates results in a significant faster lowering of the pH. Also, the stability of L. rhamnosus IMC 501®, L. paracasei IMC 502® and SYNBIO® during storage at 4 °C for 28 days in buckwheat flour- and oat bran-supplemented samples was remarkably enhanced. The second aim of the study was to develop a new synbiotic product using the best combination of probiotics and prebiotics by promoting better growth and survival and be acceptable to the consumers with high concentration of probiotic strain. This new product was used to conduct a human feeding trial to validate the fermented milk as a carrier for transporting bacterial cells into the human gastrointestinal tract. The probiotic strains were recovered from fecal samples in 40 out of 40 volunteers fed for 4 weeks one portion per day of synbiotic fermented milk carrying about 10⁹ viable cells.