纳豆芽孢杆菌固态发酵小米糠产抗氧化肽工艺优化

为提高小米糠蛋白资源的利用率,为小米糠的深加工提供参考,采用纳豆芽孢杆菌对小米糠进行固态发酵以获得小米糠抗氧化肽。在单因素试验的基础上以小米糠发酵后水提液的总抗氧化能力(total antioxidant capacity,T-AOC)为指标,使用Plackett-Burman试验对发酵条件进行筛选,然后使用响应面法对发酵条件进行优化,并测定优化后小米糠水提液的多肽含量和1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力。结果显示最适发酵条件为:小米糠平均粒径0.22 mm(60~80目)、菌液接种量0.4 mL(约108 CFU/mL)、初始pH 6.7、发酵时间26 h、发酵温度35℃。此条件下小米糠固态发酵后提取液的T-AOC实际值为(344.51±8.02)U/g小米糠,多肽提取量为(68.37±0.92)mg/g小米糠,清除DPPH自由基IC50为0.12 mg/mL。该研究表明,小米糠固态发酵条件经过优化后能够获得具有较高抗氧化能力的生物活性肽。     

Evaluation of antioxidant and antimicrobial properties of finger millet polyphenols (Eleusine coracana)

Phenolic acids from finger millet (Eleusine coracana) milled fractions (whole flour, seed coat, 3%, 5% and 7%) were isolated and their antioxidant and antimicrobial properties were evaluated. Acidic methanol extracts from seed coat to whole flour were rich in polyphenol content and were found to be stable up to 48 h at pH 4, 7, and 9 as studied by ultraviolet spectroscopy. Diadzene, gallic, coumaric, syringic and vanillic acids were identified as major phenolic acids from the extracted phenolics. Diadzene content was highest in concentration in the 5% flour. The reducing power of seed coat extract was significantly (p < 0.05) higher than that of whole flour extract. Antioxidant activity (AA) as determined by the β-carotene–linoleic acid assay indicated that the AA was highest in seed coat extract (86%), whilst at the same concentration it was only 27% in the whole flour extract. The seed coat extract showed higher antimicrobial activity against Bacillus cereus and Aspergillus flavus compared to whole flour extract. From these observations, it can be inferred that the polyphenols are responsible for the microbial activity of the millet and the results indicate that potential exists to utilise finger millet seed coat as an alternative natural antioxidant and food preservative.     

Comparative study of phytic acid content,in-vitro protein digestibility and amino acid composition of different types of flat breads

Phytic acid content of eight different types of leavened and unleavened flat breads was determined. It was highest in unleavened and non-fermented whole wheat chapati and lowest in the leavened and fermented white wheat flat bread roghni nan. The effect of baking conditions, bread composition and phytic acid content on in-vitro digestibility of protein was measured using a pepsin multienzyme pH stat technique. The amino acids released were separated by ultrafiltration. The rate of protein digestibility of flat bread and amino acid released depended upon the type of flour used, baking conditions, phytic acid content and other antiproteolytic constituents of breads. Leavening and fermentation of breads resulted in an increase of protein digestibility and availability of amino acids. Addition of soya flour increases the protein digestibility of breads whereas millet flour decreases it.     

挤压和发酵对小米多肽ACE抑制活性及抗氧化作用的影响

以小米为原料,制备具有血管紧张素转换酶(ACE)抑制作用的食源性活性多肽。采用挤压和发酵的方法对小米粉进行处理,研究其对小米蛋白消化率的影响,同时对在胃蛋白酶-胰酶水解条件下得到的小米多肽进行ACE抑制活性和抗氧化能力分析。结果表明,相比于原粉,挤压和发酵对小米多肽的ACE抑制活性和抗氧化能力都有显著的影响(P<0.01);挤压对小米蛋白消化率的影响较大(53.11%);挤压小米蛋白水解肽具有较强的ACE抑制活性(IC50=0.057 mg肽/mL)、DPPH自由基清除能力(10.99μmol/g肽)和铁离子还原能力(82.92μmol/g肽)。     

ESR spectroscopic study reveals higher free radical quenching potential in kodo millet (Paspalum scrobiculatum) compared to other millets

Six different millets kodo millet (Paspalum scrobiculatum), finger millet (Eleusine coracana), little millet (Panicum miliare), foxtail millet (Setaria italica), barnyard millet (Echinochloa utilis) and great millet (Sorghum bicolor) grown in India and their white varieties were screened for free radical quenching of 1,1, Diphenyl-2-picrylhydrazyl (DPPH) by electron spin resonance (ESR). Methanol extracts of the kodo millet flour showed 70% DPPH quenching in comparison to other millet extracts which showed 15–53%. The white varieties of great millet, finger millet and foxtail millet showed lower quenching than their coloured counterparts, indicating that phenolics in the seed coat could be responsible for the antioxidant activities. However, the content of the phenols and tannin in these grains did not correlate with the antioxidant activities. Kodo millet had the highest DPPH quenching activity followed by great millet and finger millet. Cooking of kodo or finger millet by roasting or boiling reduced the activity. Fractionation of kodo millet in to husk and endosperm also decreased the activity and the phytochemicals appear to act synergistically.     

发酵麸皮混合物对面包品质的影响

为改善麸皮面包的品质,增加麸皮的利用率,本实验应用甜酒曲联合酵母发酵麸皮、黄豆和花生的混合物,得到发酵麸皮混合物。以面粉+发酵麸皮混合物总量为100 g(面粉90 g、发酵麸皮混合物10 g)计,制备发酵麸皮混合物面包(简称发酵麸皮面包),以普通面包、麸皮面包及添加黄豆、花生混合物的非麸皮添加物面包为对照,对这几种面包的品质、风味物质及抗氧化活性进行分析。结果表明:黄豆、花生的添加能够起到提升面包风味的作用;发酵麸皮混合物的添加可以改善麸皮面包的品质,其感官评分、弹性、硬度和色差L、b值极显著优于麸皮面包(P0.01),而与普通面包比较没有显著差异(P0.05);与3种对照面包样品比较,发酵麸皮面包的醇类、酯类和醛类等风味成分种类较多,且分布均匀,而且还检测出其特有的风味物质,分别为吡嗪类、呋喃类、乙基酯类;发酵麸皮面包的多酚、黄酮含量以及抗氧化活性指标也均最高。综上,发酵麸皮混合物能够改善麸皮面包的品质,并提高面包的抗氧化活性。     

Effect of natural fermentation on phytate and polyphenolic content and in-vitro digestibility of starch and protein of pearl millet (Pennisetum typhoideum)

Natural fermentation at 20, 25 and 30°C for 72 h brought about a significant reduction in phytic acid content of pearl millet (Pennisetum typhoideum Rich) flour. The phytate content was almost eliminted in the flour fermented at 30°C. An increase in polyphenol content of fermented flour was noticed, the higher the temperature of fermentation the greater was the increase in polyphenol content of pearl millet. An improvement in starch as well as protein digestibility (in vitro) was noticed at all the temperatures of natural fermentation, the highest being at 30°C.     

氨基酸均衡小米复合粉制备及发酵乳体外消化分析

将小米与乳清分离蛋白粉和大豆分离蛋白粉复配,通过正交实验确定最优氨基酸均衡小米复合粉的质量配方;评价体外胃肠消化过程对小米浓浆未发酵组和小米发酵乳组的多酚、黄酮及抗氧化性的影响。结果表明：小米复合粉最佳质量配方为：小米粉66.8%,乳清分离蛋白粉16.6%,大豆分离蛋白粉16.6%;未发酵组和发酵乳组的多酚含量、DPPH、ABTS和羟基自由基清除率在胃、肠消化的各个阶段都显著增加。黄酮含量和铁还原力在胃消化阶段呈正增长而在肠消化时略微减少。发酵乳组的抗氧化能力在消化的每个时间段都要强于未发酵组,说明发酵工艺可以提升产品的抗氧化性。     

小米挤压粉与小米生粉理化性质及营养品质的差异比较

为了全面分析挤压膨化处理对小米粉品质特征的影响,本文系统比较了小米挤压粉与小米生粉理化性质及营养品质的差异,结果发现:小米挤压粉的密度极显著低于小米生粉(P<0.01),而粒径(P<0.01)和静止角(P<0.01)极显著高于小米生粉。挤压膨化后,小米挤压粉亮度(L*)减小、色泽(a*)变暗、肉眼可观察到色泽的差异。挤压膨化过程中产生较多阈值较低,风味贡献较大的醛类、呋喃类和吡嗪类挥发性风味物质,使得小米挤压粉的风味明显优于小米生粉。醛类,尤其是己醛(其相对质量分数高达34.58%),是小米挤压粉的主要风味贡献物质。与小米生粉相比,小米挤压粉的干基脂肪含量和直链淀粉含量分别减少28.92%和28.21%,但多不饱和脂肪酸含量增加21.08%,其中亚油酸增加19.92%、亚麻酸增加63.40%。据此推测,适量添加小米挤压粉将有利于增强小米制品的风味、改善成品口感、提高成品质量。     

不同粒径小米粉对面团流变特性及馒头质构特性的影响

为研究小米粉添加对面团流变特性和馒头制品质构特性的影响,分别选取不同粒径的粳性和糯性小米粉,利用损伤淀粉测定仪、快速黏度分析仪等对不同小米粉的损伤淀粉含量和糊化特性进行分析,通过流变仪测定小米面团的流变学特性,结合扫描电镜观察小米面团微观结构变化,并利用质构仪测定小米馒头的质构特性。结果表明：随着小米粉粒径的减小,多数品种小米粉（除冀谷39和汇华金米）损伤淀粉的碘吸收率增加;受直支比的影响,相同目数下,粳性小米粉的峰值黏度、谷值黏度、最终黏度和回生值较糯性小米粉大。流变学研究表明,除汇华金米和冀谷39,储能模量与损耗模量随角频率增加总体上升。扫描电镜观察发现小米粉的添加使面团结构更加松散。小米粉的添加会对馒头质构性质中硬度、咀嚼性和弹性等有一定程度的负面影响。主成分分析表明馒头咀嚼性、损伤淀粉、峰值黏度、谷值黏度、最终黏度、崩解值和回生值可作为区分粳糯品种和馒头品质特征的指标。     

Physicochemical,functional and antioxidant properties of flour from pearl millet varieties grown in India

Indian pearl millet varieties were selected, milled to flour and studied for their proximate composition, hunter color, functional, and antioxidant properties. Proximate composition and hunter color values differed significantly (p < 0.05) among varieties. Hunter L* value was found the highest for HHB-223 flour whereas a*, b* and ΔE was the highest for W-445 flour. Flours also showed significant variations in their total phenolic content (TPC), total flavonoids content (TFC), antioxidant activity (DPPH) and metal chelating activity. Variety GHB-732 showed the highest values for TPC (3137 µg GAE/g) and DPPH (46.7 %) activity. TFC was, however, found the highest for HC-10 (2484 µg CE/g) variety. Several significant correlations were observed among different flour properties as revealed by both pearson correlations and principal component analysis. Formulation of chapatti resulted in decrease in TPC, TFC, DPPH values when compared to its flour. However, reverse was observed for metal chelating activity.     

不同品种小米主要营养成分 及氨基酸组分评价

以10种山西主推品种小米为原料,测定小米中水分、蛋白、脂肪、碳水化合物等营养成分,用超高效液相色谱仪测定氨基酸含量,通过模糊识别法和氨基酸比值系数法,结合全鸡蛋蛋白模式和FAO/WHO模式,对不同品种小米主要营养成分及氨基酸含量分析评价。结果表明,不同品种小米的营养成分含量存在差异,小米蛋白变幅为11.43%~13.72%,脂肪变幅为3.75%~5.34%,碳水化合物变幅为81.30%~84.60%,总氨基酸含量变幅为9.04%~11.34%,水分含量变化范围在10.35%~12.37%。10种小米中富含17种氨基酸,其中必需氨基酸种类齐全,含量丰富,尤其谷氨酸和亮氨酸含量较高。汾选3号有5种氨基酸的RAA及RC在1左右,EAAI为0.80,接近1,表明其为良好蛋白质源,营养价值与利用率较高。晋谷21号鲜味氨基酸含量占比较高,鲜味较浓,更容易受到消费者的欢迎与喜爱。     

球磨改性对小米全粉理化特性及其面条品质特性的影响

小米兼具营养价值与药用价值,为提高小米的附加值和小米面条的加工品质,本实验利用球磨技术对小米全粉进行改性处理,探究不同球磨处理时间（0.5、1、2、4、6、8 h）对小米全粉营养成分、水合特性、糊化特性、流变特性、结晶结构及面条品质的影响,并分析部分理化性质与面条品质的相关性。结果表明,随着球磨时间延长,小米全粉的结晶结构破坏较明显,损伤淀粉质量分数显著增加,直链淀粉质量分数不断减少（除8 h外）,面粉亮度由77.27升至81.37。同时,球磨处理使小米全粉峰值黏度、谷值黏度和最终黏度均显著上升（P＜0.05）,分别由1 478、665 Pa·s和1 384 Pa·s提升至3 271（球磨1 h）、982 Pa·s（球磨2 h）和2 199 Pa·s（球磨2 h）,同时使水合特性（持水力、膨润力）显著提升（P＜0.05）。当球磨时间为4 h时,面团的凝胶网状结构愈发均匀致密,制作的小米面条质构、蒸煮品质均最佳。相关性分析结果表明,面条质构特性（弹性、胶黏性、咀嚼性）、感官品质（色泽、外观、黏性）与直链淀粉质量分数呈极显著负相关（P＜0.01）,与损伤淀粉和支链淀粉质量分数整体上呈极显著正相关（P＜0.01）。面条的蒸煮品质（断条率）与直链淀粉质量分数呈极显著正相关（P＜0.01）,与损伤淀粉和支链淀粉质量分数呈极显著负相关（P＜0.01）;且糊化黏度与面条品质相关性也较强。综合分析,球磨技术对小米全粉的改性处理可用于生产较高品质的小米面条。     

Effect of addition of protein concentrates from natural and yeast fermented rice bran on the rheological and technological properties of wheat bread

The effect of substituting wheat flour with 0%, 5%, 10% and 15% protein concentrates from natural and yeast fermented rice bran on the rheological properties of their dough and bread properties was studied. Rheological properties of wheat dough were influenced by addition of rice bran protein concentrates. Overall acceptability score and specific loaf volume of 100% wheat bread were not significantly different from composite bread up to 10% rice bran protein substitution, and therefore, the optimised level of substitution was established. The optimised composite bread contained higher total amino acid content, radical scavenging activity and ferric reducing ability power (43.04–48.87 g/100 g, 182.77–201.65   mmol TEAC/100 g and 613.29–637.81 mmol TE/100 g) than control (33.86 g/100 g, 109.43 mmol TEAC/100 g and 540.13 mmol TE/100 g). Springiness, cohesiveness and resilience values of wheat bread were not significantly different from composite bread. Scanning electron microscopy revealed that composite bread had surfaces with embedded granules like protein deposits with small spores.     

谷糠多酚对酒精性胃黏膜损伤的保护作用

目的：初步阐明谷糠多酚对酒精性胃黏膜损伤的保护作用以及具体分子机制,为谷糠多酚在饮酒人群胃黏膜损伤营养干预方面的应用提供科学依据。方法：雄性Wistar大鼠连续3 周每天灌胃50 mg/kg mb谷糠多酚,干预结束后通过灌胃体积分数75%乙醇溶液建立急性酒精性胃黏膜损伤模型;利用不同剂量（1～15 μg/mL）谷糠多酚对人胃黏膜上皮细胞（GES-1）处理24 h,继而通过1 000 mmol/L酒精继续作用12 h建立酒精性GES-1细胞损伤及干预模型;通过解剖观察大鼠胃组织形态学及病理结构,评价谷糠多酚对大鼠胃黏膜组织的保护作用;结合细胞形态变化及存活情况评价谷糠多酚对GES-1细胞的保护作用;通过测定氧化应激和细胞凋亡相关指标,评价谷糠多酚对急性酒精性胃黏膜损伤大鼠及GES-1细胞的抗氧化和抑制凋亡能力的影响。结果：谷糠多酚可以有效预防酒精引起的大鼠胃黏膜及GES-1细胞损伤,极显著缓解酒精引起的GES-1细胞活性氧（reactive oxygen species,ROS）水平升高（P＜0.01）;同时极显著缓解大鼠胃黏膜组织和GES-1细胞中丙二醛（methane dicarboxylic aldehyde,MDA）水平升高（P＜0.01）,提高超氧化物歧化酶（superoxide dismutase,SOD）活力,明显抑制酒精引起的细胞凋亡。结论：谷糠多酚能够通过缓解酒精引起的胃黏膜上皮细胞氧化损伤从而保护胃黏膜。     

Chemical,antioxidant, functional and thermal properties of rice bran proteins after yeast and natural fermentations

The paper focuses on the chemical, antioxidant, functional and thermal properties of rice bran proteins after yeast, natural fermentations and unfermented rice bran. Protein content of yeast‐fermented rice bran protein concentrate (YFRBPC), naturally fermented rice bran protein concentrate (NFRBPC) and unfermented rice protein concentrate (UFRBPC) were 72.50%, 68.92% and 65.73%, respectively, while ash content were 4.72%, 4.61% and 3.04%, respectively. The total amino acids of YFRBPC, NFRBPC and UFRBPC were 123.16, 118.45 and 99.39, respectively. DPPH radical inhibition of YFRBPC, NFRBPC and UFRBPC were 58.62%, 55.29% and 47.14%, respectively, while ferric reducing ability power were 0.73, 0.58 and 0.41 mmol TE per gram, respectively. The highest foam capacity of UFRBPC (57.56%), NFRBPC (64.15%) and YFRBPC (76.00%) was observed at pH 9.0. YFRBPC and NFRBPC were lighter in colour than UFRBPC. YFRBPC had higher denaturation temperature and enthalpy value than NFRBPC and UFRBPC. The β‐sheets structures were more in YFRBPC and NFRBPC than UNFBPC.     

Impact of brown foxtail millet (Setaria italica) flour on thermo-mechanical properties of flours from different rice varieties

The physical, functional and thermo-mechanical properties of rice flours prepared from long, round and medium rice grain and of foxtail millet (Setaria italica) flour were investigated. The impact of foxtail millet flour addition on the thermo-mechanical properties to the rice flours was also explored. Rice flour from long grain had higher amylose content (26.37%), while the rice flour from round grain had better hydration properties compared to the other rice flours. The dough from long grain rice flour exhibited higher starch gelatinisation temperature and cooking stability and lower starch retrogradation compared to the other investigated rice flours. Foxtail millet flour addition to the rice flours exerted a lower impact on the thermo-mechanical properties of the dough based on rice flour from long grain compared to the other investigated rice flours. These differences might be due to the differences in terms of starch properties and proximate composition of the flour samples.     

Antioxidant properties of commercial soft and hard winter wheats (Triticum aestivum L.) and their milling fractions

The total phenolic content (TPC), total antioxidant activity (TAA), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging capacity, inhibition of coupled oxidation in a β‐carotene–linoleate model system, iron(II) chelation activity and inhibition of copper‐induced oxidation of human low‐density lipoprotein (hLDL) cholesterol of 80% ethanolic extracts of soft and hard winter wheat samples and their milling fractions, namely flour, germ, bran and shorts, were investigated. Soft wheat extracts examined demonstrated higher TPC and TAA compared to those of hard wheat extracts. The germ fraction possessed the highest TPC, followed by bran, shorts, whole grain and flour for both wheat types examined. The TAA of both wheat types showed similar results except that shorts performed better than bran in this assay. Free radical scavenging properties of whole grain and milling fractions of both soft and hard wheat samples were examined against DPPH radical. The germ and flour fractions demonstrated the highest and lowest DPPH radical scavenging activity, respectively, among wheat fractions. Wheat extracts were also efficient in preventing bleaching of β‐carotene, which is also known to be free radical mediated. In the iron(II) chelation assay the flour extracts demonstrated excellent activity, while the germ extracts showed a weak activity. The trends were similar in both soft and hard wheat for the iron(II) chelation assay. Wheat extracts also inhibited copper‐induced oxidation of hLDL. In LDL oxidation assay, wheat extracts performed better than the reference antioxidant, ferulic acid. Thus wheat phenolics may serve as effective antioxidative components as measured by in vitro techniques. Copyright © 2005 Society of Chemical Industry     

固态发酵对麸皮抗氧化特性及全麦面包感官品质的提升作用

用植物乳杆菌LB-1和酿酒酵母对小麦麸皮进行固态发酵,利用发酵麸皮重组全麦粉制备全麦面包,并对固态发酵麸皮的抗氧化特性及全麦面包的色泽、组织结构、风味、口感等感官品质进行分析.结果表明:经过乳酸菌LB-1与酵母菌协同发酵36?h后,麸皮的总游离氨基酸、可溶性蛋白、可溶性多酚和可溶性阿拉伯木聚糖分别增加了0.44、0.8...     

Influence of enzymatic treatment on the nutritional and functional properties of pea flour

The effect of enzymatic treatment on the nutritional value and functional properties of pea flour was investigated. Pea flour was hydrolyzed with acid protease from Aspergillus saitoi, to give two different hydrolyzed pea flours. This enzymatic treatment led to a significant (p < 0.05) decrease in crude and true protein and to an increase of free amino acids and non-protein nitrogen. The nutritional value decreased, but an increase in the avilability of protein was expected as result of lower trypsin inhibitor activity and phytic acid content in hydrolyzed pea flours. The amino acid profile of unhydrolyzed pea flour was slightly modified after enzymatic hydrolysis, increasing (significantly) the isoleucine, leucine, lysine, cystine, phenylalanine, threonine, alanine, arginine and aspartic acid contents as a result of the added enzyme. In addition, enzymatic treatment released hydrophobic amino acids, which significantly improved the protein solubility at acid pH, the oil absorption capacity and the emulsification capacity of pea flours. Protein solubility, foaming capacity, foam stability, water absorption capacity, gelation capacity and green colour decreased. It was thus confirmed that treatment with acid protease improves some functional properties of pea flour, but the effect on nutritional properties was unclear.