瓜尔豆胶在饺子粉中的应用

饺子是我国北方人民特别喜爱的一种面制食品."好吃莫过饺子"便是广大群众对其喜爱的真情表达.随着生产水平的日益提高,人们越来越要求饺子的质量--晶莹剔透、爽滑筋道.好的饺子粉应该是面筋数量高、质量好且可操作性好.为了满足市场需求,许多面粉加工企业通过提高优质小麦配比来调整饺子专用粉的面筋质量(拉伸阻力增大).为缓和面筋强度提高造成的饺子口感过硬问题,辅以添加剂进行改良.     

Soybean Flour/Oil and Wheat Bran Effects on Characteristics of Cassava (Manihot esculenta Crantz) Flour Extrudate

Adding soybean flour, soybean oil and wheat bran to cassava flour increased the percentage of crude protein/fat and crude fiber respectively in the blends. Crude protein or extrudate correlated negatively (P<0.01) with expansion, water solubility or total reducing sugars and positively (P<0.01) with bulk density, and water absorption. Crude fiber of extrudate correlated negatively (P<0.01) with expansion, bulk density and total reducing sugars. At 4% soybean oil addition, extrudate expansion and WSI were highest, while bulk density and WAI were lowest. Extrudates became more yellow in color on addition of soybean flour.     

An Automated Cassava Peeling System for the Enhancement of Food Security in Nigeria

Cassava is second only to sweet potato as the most important starchy root crop of the tropical world. In most parts of the tropics, cassava is grown on small plots. However, in some countries, e.g. Mexico, Brazil and Nigeria, large plantations have been started and interest in mechanization is growing. The degree of mechanization depends on the size of the land and availability of machines for each unit operation involved in cassava processing. However, of all the unit operations involved in cassava processing, cassava peeling remains a serious global challenge to process engineers. An automated cassava peeling machine was thus developed in the Department of Agricultural Engineering, Federal University of Technology, Akure. The design of the machine was based on the development and modification of the peeling tool of previous cassava peeling machines and the peeling principle is by impact. This machine was evaluated using newly harvested improved variety of cassava tuber (TMS 30572) grouped into different sizes: 100 ≤ L < 140, 140 ≤ L < 180, 180 ≤ L < 220, 220 ≤ L < 260, and 260 ≤ L < 300. The speed of the machine varies from 100 – 600 rpm while machine operational parameters such as throughput capacity, peeling efficiency, mechanical damage, quality performance efficiency and peel retention were determined for each size. Results revealed that throughput capacity ranged from 76 – 442 kg/h, peeling efficiency ranged from 50 – 75%, mechanical damage ranged from 12 – 44%, quality performance efficiency ranged from 22 – 66%, and peel retention ranged from 7.2 – 33%. These results show appreciable improvement over manual method and existing machines.     

Texture and Microstructure of Cassava (Manihot esculenta Crantz) Flour Extrudate

Cassava flour (Manihot esculenta Crantz) was texturized by single-screw extrusion processing. Relationships between texture and micro-structure as a function of extrusion variables were examined. The effect of feed moisture or screw speed was significant (P < 0.01) on all textural parameters except springiness and energy first bite. Hardness, gumminess (P < 0.05) fracturability and cohesiveness (P < 0.01) decreased with increasing temperature. Hardness, fracturability and firmness were lowest at screw speed 520 rpm with feed rate 300g/min, 120–125°C and 11% feed moisture. Scanning electron micrographs showed structural change from a coarse cell mass at high feed moisture to a porous, thin-walled structure with decreased feed moisture.     

湘味挤压面粉熟食复配抗氧化剂的研究

以过氧化值(POV)、酸价(AV)为考察指标,采用Schaal烘箱加速氧化试验法,研究增效剂(柠檬酸CA)与合成抗氧化剂(TBHQ、BHT、BHA、PG)复配,合成抗氧化剂、增效剂CA与天然抗氧化剂(茶多酚TP、甘草提取物LRNO)复配对湘味挤压面粉熟食的抗氧化性的影响,通过比较产品预测货架期从而得出最佳的复合抗氧化剂组。结果表明:CA对不同合成抗氧化剂均具有协同增效作用,除对TBHQ增效无显著性差异(P0.05),其余均有显著性差异(P0.05)。TP对TBHQ+CA、LRNO对TBHQ+CA+TP均具有较强的协同增效作用,增效有显著性差异(P0.05)。添加抗氧化剂0.05‰TBHQ+0.025‰CA+0.05‰TP+0.05‰LRNO可使挤压面粉熟食在20℃条件下的预期贮藏时间从64 d延长至136 d,为抗氧化效果最佳的复配抗氧化剂。     

无铝多效泡打粉在面制食品中的应用

将研制的Ⅰ型、Ⅱ型无铝泡打粉与市售的含铝泡打粉A、无铝泡打粉B和C应用到磨堡蛋糕、甜馒头和油条中,通过比较及分析其产品的感官、比容、质构等特性,确定研制的泡打粉的性能.结果表明、研制的Ⅱ型泡打粉在所有产品中都能起到比较好的作用,在蛋糕(2％)、馒头(2.5％)、油条(3.5％)产品中的比容分别为2.65 mL/g、1.76 mL/g、4.11 mL/g,同时质构特性各指标达到或优于市售泡打粉的产品水平,具有较好的应用前景.     

Lipases and Their Functionality in the Production of Wheat‐Based Food Systems

In the last several decades, food industries have increasingly used lipases as a result of the functional versatility of these enzymes and their potential beneficial effects in terms of processing and product quality. This review article discusses lipases and their functional effects during cereal‐based food processing with a focus on the production of bread and cakes. Their dough and batter intermediates, respectively, are essentially semi‐solid foams that upon baking are converted into solid cellular sponges. In both cases, the lipid fraction(s) from wheat (in the case of bread and cake), egg and/or bakery fat (in the case of cake) exert major roles in gas incorporation and stabilization in the cited semi‐solid foams. An up‐to‐date overview on the (potential) substrates, the different lipase enzymes, their action mechanism, their functionality, and how they impact bread and cake quality is presented. We also hypothesize on how the observed effects can be interpreted in terms of the altered lipid chemistry.     

基于钝齿棒杆菌argGH启动子改造的L-瓜氨酸高效合成

L-瓜氨酸是尿素循环的重要中间体,在argGH编码酶的催化下易分解为L-精氨酸,在微生物体内难以大量积累。作者通过启动子替换手段,以弱启动子P-dapAB6替换调控argGH表达的启动子P-argG,构建了弱化L-瓜氨酸分解代谢途径的重组菌株Corynebacterium crenatum H-7-PdapAB6:argGH。重组菌株的转录水平和酶活力结果显示,重组菌株分解途径中argG和argH的基因表达水平下调,精胺琥珀酸合成酶ASS(argG编码)和精胺琥珀酸裂解酶ASL(argH编码)酶活分别降低91.80%和55.35%。摇瓶发酵结果表明,L-瓜氨酸的产量、糖酸转化率和生产强度分别为33.85 g/L、0.25 g/g和0.34 g/(L·h),较原始菌株分别提高了4.91、5.00和4.86倍。通过启动子替换策略,构建了L-瓜氨酸分解代谢途径弱化的工程菌株,初步实现了L-瓜氨酸的高效合成。     

Quality Evaluation of Maize Chips (Kokoro) Fortified with Cowpea Flour

Quality evaluation of “kokoro” fortified with cowpea flour (0, 10, 20, 30, and 40 %) was studied. The blends were reconstituted into a thick paste, manually moulded into kokoro stick and deep fried in hot vegetable oil at about 170°C for 5 minutes. These flour blends were analyzed for pasting, proximate and functional properties. The result showed that there was significant difference (p < 0.05) in the proximate composition in all the bends. The protein content ranged from 15.20 – 23.03% while ash content was between 1.29 – 1.90%, which increased with increase in cowpea flour. The carbohydrate, fat and fiber contents decreased with values ranging from 59.17 – 65.00%, 3.24 – 4.40% and 2.23 – 2.96%, respectively. The pasting characteristics of the maize cowpea blends gave a peak viscosity ranging from 510 – 702 cp. There was no significant difference (p > 0.05) in the pasting time and temperature. The functional properties reflected that water absorption, oil absorption and foaming capacity significantly increased with increase in cowpea flour with their values ranging from 186.67 – 210.00 g/100 g, 163.33 – 195.00 g/mg and 30.73 – 39.27% respectively. Bulk density also followed the same trend. Sample CAF (100% maize) reflected the highest dispersibility value (6.63%). No significant difference (p > 0.05) was observed in the swelling capacity and least gelatinization concentration. Although the sensory result indicated that increase in cowpea flour does not show a significant difference (p > 0.05) in the sensory parameters, the overall acceptability of the samples was highly rated.     

食品中蛋白质的功能(二) 蛋白质结构与食品功能性质的关系研究

本文综述了蛋白质的结构,以及它与食品中蛋白质功能性质(如:表面性质、水化性质、凝胶性质等)的关系,并探讨了食品蛋白质的几种功能性质的影响因素及其在食品加工中的作用。     

Physicochemical Properties and Starch Granular Characteristics of Flour from Various Manihot Esculenta (Cassava) Genotypes

ABSTRACT: Flour and starch were produced from 11 cassava genotypes. Starch and total dietary fiber contents were determined using a single-enzyme gravimetric procedure and high-performance anion exchange chromatography, pasting profiles by rotary viscometry, water holding capacity gravimetrically, and granular characteristics by scanning electron microscopy. Starch and total dietary fiber contents varied among genotypes. Flour peak viscosities, setback, and final viscosities differed significantly. Flour water holding capacity correlated with flour peak viscosity (r = 0.7). Starch granules ranged from 9 to 20 μm. Predominant granule shapes were oval, rounded, and truncated. The results provide insights into cassava genotype characteristics, and functionality of cassava starch and flour.     

(X-)-R控制图在面粉生产控制中的应用

简单描述控制图及在面粉生产过程中取同一品种不同生产时间的各批次面粉灰分值,利用(X-)-R控制图进行分析,排除生产过程的异常因素,达到了较好地稳定生产,保证质量的目的.     

Characteristics and Functionality Enhancement by Glycosylation of Bitter Melon (Momordica charantia) Seed Protein

Seeds of ripe bitter melon (Momordica charantia) contain approximately 30% protein. However, this protein, which is less functional than soy protein, may have desirable functionalities as a food ingredient after modification. Bitter melon seed protein isolate (BMSPI) was prepared under optimal extraction conditions (defatted meal to 1.3 M NaCl was 1:10 w/v; pH 9.0) and its functional properties were investigated before and after modification by glycosylation. Glycosylation was conducted at varying relative humidities (50%/65%/80%) and temperatures (40 °C/50 °C/60 °C) using a response surface central composite design. Degree of glycosylation (DG) ranged from 39.3 to 52.5%, 61.7 to 70.9%, and 81.2 to 94.8% at 40 °C, 50 °C, and 60 °C, respectively (P values < 0.0001). Denaturation temperatures of all DGs ranged from 111.6 °C to 114.6 °C, while unmodified/native BMSPI had a value of 113.2 °C. Surface hydrophobicity decreased to approximately 60% when the DG was maximal (94.8%). Solubility decreased almost 90% when the DG was maximal in comparison to the native BMSPI (62.0%). Emulsifying activity increased from 0.35 to 0.80 when the DGs were ≥80%, while emulsion stability increased from 63 to 72 min when the DGs were greater than 70%. A similar trend was observed with foaming capacity and foaming stability of the glycosylated proteins. This glycosylated BMSPI with improved emulsifying and foaming properties could be used as an ingredient in food products where such properties are required.     

木薯酒精生产技术要点

以木薯干为原料，经二次粉碎、风选，加α-淀粉酶预煮和直接蒸汽蒸煮糊化，加糖化酶糖化，加活性干酵母，采用半连续发酵工艺发酵，所生产的木薯酒精符合国标普级酒精标准，出酒率达36．8％，提高了0．5％。     

Gluten-Free Bread Making Trials from Cassava (Manihot Esculenta Crantz) Flour and Sensory Evaluation of the Final Product

The aim of this work was to evaluate the effectiveness of the use of cassava flour in bread making, and the sensory acceptability of the final product. Different baking trials were carried out by using egg white and extra-virgin olive oil, in consideration of their high nutritional value with respect to other food additives (i.e., hydrocolloids). Significant (p < 0.05) improvements of loaf specific volume (from 2.24 to 3.93 mL/g) and crumb firmness (from 9.14 to 4.67 N) were achieved by contemporarily including egg white and extra-virgin olive oil in the formulation. Cassava breads containing both these ingredients obtained the best scores from panelists for all the test breads examined and resulted attractive as the wheat bread prepared as reference.     

Direct Determination of Ca,K and Mg in Cassava Flour Samples by Laser-Induced Breakdown Spectroscopy (LIBS)

This study aims to develop a method for direct determination of Ca, K, and Mg in cassava flour samples by laser-induced breakdown spectroscopy (LIBS). LIBS instrumental parameters were evaluated using factorial design with a central point. The variables evaluated were delay time (0.0; 1.0 and 1.8 μs) and fluence (81; 2037 and 4074 Jcm^?2): both were tested in three different values. The best results obtained were with a delay time of 1.8 μs and a fluence of 4074 Jcm^?2. The proposed calibration model obtained using LIBS data presented a good correlation with reference values obtained by inductively coupled plasma atomic emission spectrometry (ICP OES). The predictive capabilities, based on the standard error of validation (SEV), were 117, 530 and 77 mg kg^?1 for Ca, K, and Mg, respectively. The proposed LIBS method was applied to the analysis of 90 cassava flour samples, and the results showed concentrations of Ca, K, and Mg of 352–1845, 1285–3187, and 320–1242 mg kg^?1, respectively.     

A Study on the Relationship Between Rheological Properties of Wheat Flour,Gluten Structure,and Dumpling Wrapper Quality

Fifty different kinds of wheat from 10 provinces in China were chosen as samples to be milled into flour. Dumpling wrappers were made from the flour and their texture qualities and rheological properties, disulfide content, sulfhydryl content, and gluten secondary structure were determined. The web structure formed by the gluten was observed under scanning electron microscopy. These results showed that the flour’s rheological properties, apart from extensibility, were significantly correlated with several aspects of the texture of the dumpling wrapper, and the degree of softening showed negative correlations, most closely with the texture quality of the dumpling wrapper. Disulfide played an important role in forming the gluten web, its content showing significant correlations with the rheological properties of the flour and the texture quality of the dumpling wrapper. The disulfide content in gluten was positively correlated with the hardness and quality of the cooked product; the sulfhydryl content showed no significant correlations with the rheological properties of the flour and the texture of the dumpling wrapper. The gluten secondary structure showed some correlation with the rheological properties of the dough, but little with the texture quality of the dumpling wrapper. Under observation by scanning electron microscopy, the weak structure was loose with large interspaces, while the strong structure was compact with few interspaces.     

Bread Making Potential of Composite Flour of Wheat-Acha (Digitaria exilis staph) Enriched with Cowpea (Vigna unguiculata L. walp) Flour

Bread-making potentials of composite flours containing 90% wheat and 10% acha enriched with 0-15% cowpea flour were investigated. Proximate composition and functional properties of the blends were studied using AOAC standard methods. Bread loaves were prepared from the blends using the straight dough method and evaluated for loaf height, loaf volume, loaf weight and sensory characteristics. Crude protein, crude fat, crude fibre and ash contents increased significantly (p < 0.05) with increase in level of cowpea flour addition, but moisture content was not significantly (p > 0.05) different among the blends. Functional properties, with exception of bulk density and swelling capacity, were significantly (p < 0.05) different among the blends. Average loaf height and loaf volume decreased significantly (p < 0.05) with increased cowpea flour but loaf weight showed opposite trend with significant (p < 0.05) differences as cowpea flour increased. However, the addition of cowpea flour significantly (p < 0.05) decreased the loaf specific volume but all enriched samples were not significantly (p > 0.05) different. Bread samples from composited blends were rated lower than bread from all wheat bread. Bread loaves from enriched composite flour with up to 10% cowpea flour were acceptable to the panelists.     

Effect of Soy Flour and Maize Flour Addition on Phase Separation in Moi-Moi from Soaked Cowpea (Vigna unguiculata) and Cowpea Flour from Different Cowpea Varieties

Two improved varieties of cowpea (IT89KO and IT90K-76) and one local variety (lsiocha) were used to investigate the effects of added soyflour and maize flour on the phase separation in moi-moi made from soaked cowpea and cowpea flour. Different levels (5%, 10%, 15%, 20% and 25%) of maize flour, soyflour and a 1:1 blend of soyflour and maize flour (soy/maize flour) were separately added. The moi-moi from the different combinations was evaluated for phase separation and per cent height of the upper layer calculated. Soaking of cowpea reduced the size of the upper layer in moi-moi compared with the use of cowpea flour. The addition of maize flour or the soy/maize flour reduced the upper layer compared with when either flour was added alone. The upper layer of moi-moi made from cowpea flour with added soy flour (21.20%) was significantly higher (p < 0.05) than moi-moi from soaked cowpea with added soy flour (15.2%). Moi-moi with added maize flour made from cowpea flour produced a significantly (p < 0.05) higher mean per cent upper layer (19.72%) compared with that from soaked cowpea (8.95%). Addition of soyflour produced the greatest upper layer for all varieties used. There were no significant (p > 0.05) differences in the per cent upper layers for moi-moi from all cowpea varieties when maize flour was added. Increasing the proportion of added flours increased the size of the upper layer. Complete prevention of the occurrence of phase separation in moi-moi by addition of soy flour and maize flour alone is not feasible.     

植物乳杆菌活菌片剂产品的功能性与稳定性研究

本研究以一株具有润肠通便功能的植物乳杆菌为研究对象,研究其活菌片剂产品的功能与稳定性,通过检测植物乳杆菌581的生长曲线和终点pH评价其对不同益生元的利用效率,采用小鼠便秘模型评估低聚果糖和植物乳杆菌581制成的片剂产品的功效,通过监测产品在4℃和28℃贮存6个月的活菌数、水分含量和水分活度评价产品稳定性。实验结果表明,低聚果糖是与植物乳杆菌581配伍制成片剂产品的优选益生元。以植物乳杆菌581与低聚果糖为主要功能成分所制备的活菌片剂产品连续7 d灌胃便秘模型小鼠能有效改善小鼠的肠道功能,具有润肠通便的功效。其中,低聚果糖能够促进植物乳杆菌581更好的发挥润肠通便功能。同时,该片剂产品在4℃储藏条件下可有效维持其活菌数达到10¹⁰ CFU/g,从而充分发挥该产品的益生功能。