Arabinoxylan content and characterisation throughout the bread‐baking process

End‐use quality of wheat (Triticum aestivum L.) is influenced in a variety of ways by nonstarch polysaccharides, especially arabinoxylan (AX). The objective of this study was to track total and water‐extractable AX (TAX and WEAX, respectively) throughout the bread‐baking process, using wholemeal and refined flour. The TAX and WEAX content and the ratio of arabinose: xylose were assessed in flour, mixed dough, proofed dough and the bread loaf, which was separated into crumb, upper crust and bottom crust. Changes in TAX during the baking process differed between the refined flour and wholemeal samples, suggesting a change in the TAX availability which we ascribe to molecular interactions and heat treatment. WEAX content dramatically decreased during baking, suggesting that oxidative cross‐linkages rendered it unextractable. Higher levels of WEAX and lower levels of arabinose substitution were correlated with higher loaf volumes for refined flour among the hard wheat varieties. Having a better understanding of the importance of both WEAX content and arabinose substitution allows for directed breeding efforts towards improved hard wheat varieties for optimum bread baking.     

Effect of Different Binders on the Physico-Chemical, Textural, Histological, and Sensory Qualities of Retort Pouched Buffalo Meat Nuggets

ABSTRACT: The functional properties of 4 binders, namely corn starch, wheat semolina, wheat flour, and tapioca starches, were evaluated to improve the quality of buffalo meat nuggets processed in retort pouches at F₀ 12.13. Incorporation of corn starch in buffalo meat nuggets produced more stable emulsion than other binders used. Product yield, drip loss, and pH did not vary significantly between the products with different binders. Shear force value was significantly higher for product with corn starch (0.42 ± 0.0 Kg/cm³) followed by refined wheat flour (0.36 ± 0.010 Kg/cm³), tapioca starch (0.32 ± 0.010 Kg/cm³), and wheat semolina (0.32 ± 0.010 Kg/cm³). Type of binder used had no significant effect on frying loss, moisture, and protein content of the product. However, fat content was higher in products with corn starch when compared to products with other binders. Texture profile indicated that products made with corn starch (22.17 ± 2.55 N) and refined wheat flour (21.50 ± 0.75 N) contributed firmer texture to the product. Corn starch contributed greater chewiness (83.8 ± 12.51) to the products resulting in higher sensory scores for texture and overall acceptability. Products containing corn starch showed higher sensory scores for all attributes in comparison to products with other binders. Panelists preferred products containing different binders in the order of corn starch (7.23 ± 0.09) > refined wheat flour (6.48 ± 0.13) > tapioca starch (6.45 ± 0.14) > wheat semolina (6.35 ± 0.13) based on sensory scores. Histological studies indicated that products with corn starch showed dense protein matrix, uniform fat globules, and less number of vacuoles when compared to products made with other binders. The results indicated that corn flour is the better cereal binder for developing buffalo meat nuggets when compared to all other binders based on physico-chemical and sensory attributes.     

A survey of water‐extractable arabinopolymers in bread and durum wheat and the effect of water‐extractable arabinoxylan on durum dough rheology and spaghetti cooking quality

BACKGROUND: Information on the variation in water‐extractable arabinopolymers (WEAP) in durum wheat and their impact on pasta quality is limited. A survey of the content of WEAP in selected bread wheat varieties and durum wheat was conducted and the influence of water‐extractable arabinoxylans (WEAX) on dough and spaghetti quality was examined by fortifying low‐WEAP durum semolina with purified WEAX. RESULTS: Bread wheat typically possessed higher levels of WEAP than durum wheat, but the latter had a greater range. Purified WEAX was extracted from bread wheat cultivar Sunlin which possessed a high level of WEAP. The extract was used to fortify semolina (0.125–2% w/w) derived from durum wheat variety Tamaroi (low WEAP). Fortification caused a near linear increase in farinograph water absorption of approximately 12% over the range of addition, leading to dough weakening. Reduced cooked pasta stickiness was observed at all levels of WEAX addition. CONCLUSION: Increased WEAX content may be a means to improve pasta quality by reducing pasta stickiness. Durum wheat showed a wide range of WEAP contents, and this may well be exploited by developing cultivars with elevated WEAP levels. © 2008 Crown in the Right of the State of New South Wales and Society of Chemical Industry.     

重组脂肪氧合酶对面团流变性质及面包品质的影响

通过测定酶促作用前后面筋蛋白（wheat gluten,WG）的自由巯基含量、表面疏水性、黏弹性等的变化,研究了重组脂肪氧合酶（pET-32a-ana-lipoxygenase,ana-rLOX）对水溶性阿拉伯木聚糖（water-solublearabinoxylan,WEAX）和WG相互作用的影响,并探讨了ana-rLOX对面包品质改良的作用。结果表明,与添加WEAX的样品相比,加入ana-rLOX和WEAX后WG的自由巯基含量下降了21%,表面疏水性指数增大,流体动力学半径增大了27.3%,WG的黏弹性明显增加;面包的硬度、胶着性、咀嚼性降低,回复性增强,明显改善了面包品质。     

Olive stone powder: A potential source of fiber and antioxidant and its effect on the rheological characteristics of biscuit dough and quality

Being waste products of olive fruits, olive stones could be used as a healthy functional food ingredient thanks to their rich antioxidant properties, nutrients and dietary fibers. In this study, wheat flour was substituted by olive stone powder at levels of 0, 5, 10 and 15%. The rheological properties of biscuit dough and proximate composition, color values, total phenolic content, antioxidant activity, textural characteristics and sensorial properties of biscuit samples were investigated. Wheat flour replacement by olive stone powder increased antioxidant activity, fat and fiber content of biscuit samples (p < 0.05). The biscuits prepared with addition of 15% olive stone powder had 30.44 ± 0.03% DPPH radical scavenging activity, 11.22 ± 0.09% crude fiber, and 26.32 ± 0.22% fat. According to results of sensory analysis, wheat flour could be substituted up to 15% by olive stone powder to prepare biscuits without causing unacceptable product in terms of sensory properties.     

面包制作过程中戊聚糖酶的作用机理

研究了戊聚糖酶对面包品质的影响.加酶面包的体积明显增加,在适宜加酶量下,面包综合品质较佳.加酶面团中可溶性戊聚糖含量显著增加,但加酶过量可导致面团中水可提取的阿拉伯木聚糖(WEAX)降解程度加剧.未加酶面团较原料面粉中的可溶性戊聚糖含量略有增加,WEAX亦有部分降解,但作用程度远低于加酶样品.适量戊聚糖酶对面包品质的改良作用的关键在于产生大量的相对分子质量适宜的WEAX.     

Refrigerated dough quality: effect of environment and genotypes of hard red spring wheat

Refrigerated dough products use wheat flour as their primary ingredient, so the quality and chemical composition of the flour determine the quality of the final product. Six varieties of hard red spring wheat, grown in 3 locations in Minnesota, U.S.A., were evaluated for use in refrigerated dough products. Total arabinoxylan percentages in the flours ranged from 0.97 to 1.54. Xylanase activity of the flour was measured and ranged from 0.20 to 0.84 mU/g. An important factor in the suitability for refrigerated dough is the syruping during storage. A large amount of variability in dough syruping was observed among the varieties and locations when the extent of dough syruping was measured over a period of 10 d. The mean dough syruping on day 10 ranged from 2.05% to 14.83%. Despite the significant interaction effect of genotype and environment, 2 varieties, Glenn and Oklee, had lower dough syrup formation with greater stability across growing locations and storage days than other varieties. Practical Application: Refrigerated dough production is one of the fastest growing segments of the ready-to-use food industry. Well-formulated and processed refrigerated doughs are practical to consume and should stay fresh during extended periods of storage; thus, maintenance of dough quality during refrigeration is critical. This study was designed to perform the research on genotypic and environmental effects on variations in dough syruping during refrigeration storage of doughs from hard red spring wheats.     

临夏市面制品和焙烤食品中铝含量检测及危害分析

目的初步了解临夏地区面制食品中铝的污染情况,并以此来评估消费者可能从食物中摄入铝的情况和相关的健康风险。方法对临夏各销售渠道地区生产销售的不同品种面制品进行市场监查、样品采集和测定分析。结果 1000份样品中检出铝残留238份,检出率为23.8%;铝含量超标样品59份,对应不合格率为5.9%;检测最大值为540mg/kg,是限定值的5倍以上;蒸馍面制品铝超标问题较为严重,检测最大值为540mg/kg;生湿面制品铝含量都低于检出限;其他类都有不同程度的铝检出问题。结论临夏市面制品中铝超标情况较为严重,建议有针对性的对不同地区不同种类面制品中铝添加剂的监管,如临夏县和积石山保安族县的面点坊及早餐摊位,所生产的蒸馍食品、油炸食品、焙烤食品。     

Analysis of Lunasin in Commercial and Pilot Plant Produced Soybean Products and an Improved Method of Lunasin Purification

Abstract: Lunasin is a bioactive peptide present in soybean. It is important to quantify lunasin concentration in soy products to assess its potential impact as functional food. The objectives of this study were to analyze lunasin in commercial soymilk products and implement an efficient method to isolate and purify it from defatted soybean flour. Defatted soybean flour was suspended in water, and the extract was loaded in a pre‐equilibrated diethylaminoethyl column and bound proteins eluted using a step gradient of salt. Most lunasin was eluted from the column at 0.2 to 0.4M NaCl as quantified by immunoassays and purified using ultracentrifugation and ultrafiltration techniques. Lunasin purity was ≥90% and a standard curve was used to quantify its concentration in soymilk products. Concentration of lunasin in soy products, including organic soymilk, soy protein shakes, and soy infant formulas, ranged from 1.78 to 9.26 mg lunasin/100 g product. The concentration per serving ranged from 1.59 ± 0.01 to 22.23 ± 0.74 mg lunasin with variability depending on brand and size per serving. Steam‐ground‐cooked soy had the highest concentration of lunasin (22.23 ± 0.74 mg/serving), similar to some commercial products. Ground‐cooked soymilk contained roughly half the concentration of lunasin (14.39 ± 1.4 mg/serving). Soy infant formulas that used soy protein isolate revealed lower concentrations of lunasin (P < 0.05). It was concluded that all soymilk products analyzed contained lunasin, and a more efficient method to isolate lunasin with higher purity was developed. Practical Application: Soy foods have shown to play a role in cardiovascular health prevention. The quantification of lunasin in commercially available soy products can add to the already existing health claim for soy foods and encourage consumers to include soy products in their diets.     

Development of a sensitive polyclonal antibody-based competitive indirect ELISA for determination of citrinin in grain-based foods

ABSTRACT

A sensitive competitive indirect enzyme-linked immunosorbent assay (ciELISA) was developed for the detection and quantification of citrinin (CIT) in grain-based food samples. The limit of quantification (IC₂₀) of the established method was 0.10 ± 0.02 ng mL^?1, with the limit of detection (IC₁₀) being 0.04 ± 0.007 ng mL^?1 in wheat and corn flour matrices with a coefficient of variation (CV) less than 20%. The assay was very specific to CIT and showed no cross-reactivity with other mycotoxins (OTA, T-2 toxin, HT-2 toxin, DON, patulin and zearalenone). In spiked wheat and corn flours, the recoveries ranged from 86.6% to 115.6% with CVs of less than 20%. The effectiveness of this method was verified by participating in a proficiency test (PT) from the Food Analysis Performance Assessment Scheme (FAPAS) 17181 corn flour. A successful z-score (?0.6) for this PT sample showed that the present method is comparable to the instrumental methods used by other laboratories in the PT testing scheme. A small survey of grain-based foods was conducted using this method and CIT was detected in 43% of the samples up to a concentration of 17.7 ng g^?1. This method is suitable for sensitive and rapid quantitation of citrinin in wheat and corn matrices.     

Physiochemical Properties and Probiotic Survivability of Symbiotic Corn‐Based Yogurt‐Like Product

Corn is a major grain produced in northern China. Corn‐based functional food products are very limited. In this study, a symbiotic corn‐based yogurt‐like product was developed. Corn milk was prepared through grinding, extrusion and milling, and hydration processes. Corn extrudate was prepared under the optimized conditions of corn flour particle size <180 μm, moisture content of 15% and extrusion temperature at 130 °C. The corn milk was prepared from 8% corn extrudate suspension and then milled twice with 0.1% glyceryl monostearate and 0.1% sucrose ester as emulsifiers. The corn milk was mixed with sugar (5%), glucose (2%), soy protein isolate (0.75%), inulin (1%), polymerized whey protein (0.3%) and xanthan gum (0.09%) as thickening agents. The mixture was fermented at 35 °C for 6 h using a probiotic starter culture containing L. plantarum. Chemical composition (%) of the symbiotic corn‐based yogurt‐like product was: total solids (17.13 ± 0.31), protein (1.12 ± 0.03), fat (0.30 ± 0.05), carbohydrates (15.14 ± 0.19), and ash (0.16 ± 0.02), respectively. pH value of this symbiotic product decreased from 4.50 ± 0.03 to 3.88 ± 0.13 and the population of L. plantarum declined from 7.8 ± 0.09 to 7.1 ± 0.14 log CFU/mL during storage at 4 °C. SDS‐PAGE analysis showed that there were no changes in protein profile during storage. Texture and consistency were also stable during the period of this study. It can be concluded that a set‐type corn‐based symbiotic yogurt‐like product with good texture and stability was successfully developed that would be a good alternative to the dairy yogurt.     

Nutritional Evaluation of Cereal–Cheese Whey Mixtures

The chemical composition, amino acid content, PER, and digestibility of dehydrated sweet cheese whey, wheat flour, wheat bran, and lime-treated corn flour (nixtamal, used for making tortillas), as well as of 21 cereal-cheese whey mixtures were determined. The cheese whey was composed of 12% protein and 74% lactose. Diets containing a total of 8% protein were formulated with the cereal-cheese whey mixtures. The 50:50 (% protein) cereal-whey mixtures had the highest adjusted modified PERs, representing an increase over the cereals alone of 324% for the corn flour, 215% for wheat flour, and 177% for wheat flour, and 177% for wheat bran. The 50:50 (% protein) wheat bran mixture had the largest adjusted modified PER at 2.33 ± 0.13 (mean ± SEM) and the 50:50 wheat flour mixture, the smallest at 1.48 ± 0.21. Although the apparent digestibility was reduced from 10–14% for the latter two 50:50 cereal-whey mixtures compared to the cereals alone, this was not reflected in the PER. It was concluded that the nutritive value of all the cereals tested significantly increased with the addition of 155 25% or more (by weight) of dehydrated cheese whey.     

利用气相离子迁移谱对小麦与小麦粉挥发性物质研究

利用气相离子迁移谱(GC-IMS)对河北、山东各15个小麦样品、山东对应小麦制粉后的15个小麦粉样品的风味物质进行测定,确定一种粮食风味物质的快速测定方法。结果表明,在不经过样品前处理的条件下便可快速检测小麦及小麦粉中的挥发性有机物,主成分分析可将山东小麦和山东的小麦粉区别分开,分析时间短,操作简单。其中小麦的风味物质成分明显高于小麦粉。     

Xylanases in Wheat Separation

Hemicellulases used in the wheat separation process have resulted in better separation, purer fractions, increased plant capacity, reduced processing time etc. In order to further improve enzyme-treatment in the wheat separation process, monocomponent xylanases were evaluated. A laboratory viscosity model has been set up to evaluate the xylanases. The model showed good correlation (for a commercial hemicellulase preparation used for wheat separation) between viscosity of the wheat flour slurry and the sludge/supernatant ratio after centrifugation of the slurry. A xylanase (Novozyme 867) with excellent performance in the wheat separation process has been found. The xylanase has high activity towards soluble arabinoxylan and gives a rapid viscosity reduction of wheat flour slurries. The enzyme also has a moderate activity towards insoluble arabinoxylan, but due to the low molecular weight of the solubilized material this was not was found to contribute negatively to the enzymes' performance. The pH and temperature conditions in the wheat separation process were well within the active range of the enzyme. A pilot plant experiment showed improved yield of gluten and A-starch, with no apparent negative effect on the gluten quality.     

Optimal formulation of a product containing black wheat granules

This study describes the development process of a healthy nutritional product containing black wheat granules (BWGP), which was based on Xinjiang characteristics of miscellaneous grains and nuts. BWGP was designed and developed as a local characteristic of nutritious food, which is produced from wheat, black sesame seeds, flour, corn flour, chickpeas, walnuts, peanuts, melon seeds, red dates, and brown sugar. The product was then underwent sterilization process followed by the inflated or vacuum quantitative packing as an instant ready-to-eat food. The best formula (%) was determined as follows: black wheat 30, corn flour 20, flour 15, chickpeas 15, black beans 2, peanuts 3, melon seeds 3, walnut 3, black sesame seeds 4, red date powder 15, sugar powder 15, maltodextrin 15, and sunflower oil 20. BWGP has several advantages, which include: a regional characteristic, simple production methods, and rich flavors. Overall, our study focused on the nutritional, flavor, and compositional effects and how a food product can be made healthier, more sustainable or more acceptable to the consumer.     

Analysis of main physicochemical parameters in purple wheat with different milling technology

With layered milling flour technology, the efficiency of the nutrient distribution and hardness was demonstrated with the purple and normal wheat separation milling. The results showed that the total content on amino acid in purple wheat was 8.2–12.9% higher than the common wheat. Compared with the main nutriments Se, Fe, Ca between purple wheat and common wheat, the results showed that different milling methods treatment are capable of separating the different wheat flour from endosperms, bran, and aleurone layers. Micro and physicochemical characterization of different wheat flour and layers by means of microscopy techniques and images analysis provided relevant qualitative and quantitative information, which can be useful for the study of the microstructure of purple and normal wheat products and also for its processing and utilization.

Practical applications

Color wheat has gained more importance in the recent years due to its health benefits. Purple wheat is balanced in amino acid, mineral elements, and Wet gluten. Therefore, purple wheat is an excellent flour product source according to the Association of Official Agricultural Chemists (AOAC). Purple wheat rich in amino acid such as leucine, proline, serine, glycine, threonine, and glusate provide important roles in the quality and nutrient value of dough. Lately, the food industry has had a strong interest on purple wheat due to their benefits such as better delivery of protein components, and greater stability and functional performance. Using purple wheat as an ingredient in a flour product will not only improve the nutritional profile of the dough but will also substantially increase the natural microelement content. This study describes the development and characterization of flour product containing purple wheat.     

优良乳化特性麦麸阿拉伯木聚糖制备工艺优化

乳状液粒径大小和分布与乳状液乳化特性有着密切的关系,为得到优良乳化特性麦麸阿拉伯木聚糖,以乳液平均粒径及分布为考察指标,研究了碱提温度、碱提时间、NaOH浓度和pH单因素对麦麸阿拉伯木聚糖乳状液粒径的影响,并采用正交实验方法对麦麸阿拉伯木聚糖的碱提工艺条件进行优化。结果表明,在碱提温度85 ℃、碱提时间180 min、NaOH浓度0.15 mol/L、pH4.3条件下,所提取麦麸阿拉伯木聚糖平均粒径为(0.4859±0.009) μm低于阿拉伯胶的(0.5494±0.013) μm,并具有相近的分布指数(0.147±0.015,0.113±0.016,p>0.05)。因此,通过优化提取条件,制备具有优于或接近阿拉伯胶的乳化性质的麦麸阿拉伯木聚糖是可行的,为阿拉伯木聚糖的工业生产提供理论参考。     

Precooked sorghum flour as proper vehicle of ACE-I and DPP-IV inhibitory sorghum peptides

Sorghum flour was heat treated for producing an instant dispersion ingredient. The precooked sorghum flour was added with ACE-I and DPP-IV inhibitory sorghum peptides (3.0 g peptide 100 g⁻¹). The product was reconstituted in water, and peptide bioaccessibility was evaluated by equilibrium dialysis method after simulated gastrointestinal digestion. Total peptide dialysability of precooked sorghum flour added with sorghum peptides was higher than those obtained for precooked sorghum flour (315.9 ± 14.8 vs. 45.2 ± 5.6 µmol, respectively) (P < 0.05). The ACE-I and DPP-IV-IC₅₀ values of the bioaccessible peptides from the bioactive product were lower than those obtained for precooked sorghum flour ingredient (1.04 ± 0.12 vs. 1.82 ± 0.09 and 0.86 ± 0.02 vs. 2.12 ± 0.08 mg protein mL⁻¹, for ACE-I and DPP-IV, respectively) indicating a higher activity. Precooked sorghum flour was a good vehicle since it did not affect the bioaccessibility of ACE-I and DPP-IV inhibitory peptides provided by sorghum protein hydrolysate.     

Effect of Different Extrusion Parameters on Dietary Fiber in Wheat Bran and Rye Bran

Wheat bran and rye bran are mostly used as animal feed today, but their high content of dietary fiber and bioactive components are beneficial to human health. Increased use of bran as food raw material could therefore be desirable. However, bran mainly contains unextractable dietary fiber and deteriorates the sensory properties of products. Processing by extrusion could increase the extractability of dietary fiber and increase the sensory qualities of bran products. Wheat bran and rye bran were therefore extruded at different levels of moisture content, screw speed and temperature, in order to find the optimal setting for increased extractability of dietary fiber and positive sensory properties. A water content of 24% for wheat bran and 30% for rye bran, a screw speed of 400 rpm, and a temperature of 130 °C resulted in the highest extractability of total dietary fiber and arabinoxylan. Arabinoxylan extractability increased from 5.8% in wheat bran to 9.0% in extruded wheat bran at those settings, and from 14.6% to 19.2% for rye bran. Total contents of dietary fiber and arabinoxylan were not affected by extrusion. Content of β‐glucan was also maintained during extrusion, while its molecular weight decreased slightly and extractability increased slightly. Extrusion at these settings is therefore a suitable process for increasing the use of wheat bran and rye bran as a food raw material.     

Validation of HPLC-UV Methods for the Quantification of Betaine in Foods by Comparison with LC-MS

The importance of dietary betaine is increasingly recognized. The aim of this study was to develop a simple high-performance liquid chromatography with standard ultraviolet spectrometric detection (HPLC-UV) method for betaine (N,N,N-trimethylglycine) determination in foods after derivatization. Two methods were used for betaine derivatization. Thereafter, derivatized betaine was quantified using HPLC-UV, and the results were compared with liquid chromatography mass spectrometry (LC-MS). The established derivatizing agent 2′-naphthacyl triflate and a novel derivatizing agent 2-bromo-2′-acetonaphthone produced the same cationic derivative when they react with betaine. The calibration curves were linear up to 1000 μmol/L (R ²?=?0.9974 for 2′-naphthacyl triflate and 0.9995 for 2-bromo-2′-acetonaphthone). The limit of detection was 1 μmol/L for both methods (2′-naphthacyl triflate and 2-bromo-2′-acetonaphthone), confirming sufficient sensitivity for betaine quantification in foods. The average recovery from different food matrices (wheat flour and spinach) (n?=?12) was 99?±?9 %, 95?±?10 %, and 101?±?8 % for LC-MS, 2′-naphthacyl triflate, and 2-bromo-2′-acetonaphthone, respectively. Inter- and intra-assay coefficients of variation (CVs) in the control samples (whole wheat flour) were below 10 %. Quantitative results for foods analyzed using 2′-naphthacyl triflate and 2-bromo-2′-acetonaphthone were comparable to LC-MS (R ²?=?0.992 and 0.990), respectively. The highest betaine content (~160 mg/100 g) was found in spinach followed by faba bean, wheat flour, and beetroot. These methods can be widely used for betaine quantification because of the simplicity of the derivatization procedures, and the commercial availability of the derivatizing reagent (2-bromo-2′-acetonaphthone) or through the relatively easy synthesis of 2-naphthacyl triflate.