THE ATTITUDES OF EUROPEAN CONSUMERS TOWARD INNOVATION IN BREAD; INTEREST OF THE CONSUMERS TOWARD SELECTED QUALITY ATTRIBUTES

This survey concerns industrial bread making and has been carried out within the European project entitled EU-FRESHBAKE (October 2006 to October 2009), which concerns the bake-off technology. This technology consists in producing bread at industrial level (frozen most of the time) and to retail the bread in "baking stations" or in small vending shops.
The objectives of this survey were (1) to better understand the attitude of the European innovations in bread and (2) to understand the main determinants of it. Two main categories of consumers were observed; (1) frequent (daily) buyers with a focus on quality and pleasure and (2) less frequent buyers (once a week) with a more pronounced interest in nutrition, shelf life and energy (process). The first group was named the "crust group" and the second one the "crumb group." The "crumb group" seems to be the one that is the most interested in the outcomes of the EU-FRESHBAKE project.

PRACTICAL APPLICATIONS

This survey brings interesting information regarding the expectations of EU consumers toward innovation in bread making. Bread is a very symbolic food, carrying a lot of messages coming from religion, social classification and from well being.
Among the key messages to be withdrawn from this survey, it appears that northern and eastern Europe, and also the young population, are expecting from bread a food that must adapt to the constrain of life. It must have a long shelf life and it must carry a nutritional value. On the other hand, French and southern Europe countries are bringing more attention to the pleasure and to the freshness of the product. There is thus a complex matrix of social and qualitative attitudes toward bread from one country to the other. Innovation can be considered as a positive image in some countries, whereas it may have a very negative image in other countries.     

A review on biotechnological potential of multifarious enzymes in bread making

Baking is a universal process for the preparation of baked products like, bread, biscuits, pastries, cookies, crackers, pies, and others. Although usage of enzymes in bakery is quite old but recent developments in basic biology, biochemistry, advancements in technological approaches, and discovery of new/novel enzymes, has revolutionized the application potential of enzymes in a variety of food industries including the bakery. World over people want their foods to be free of chemical preservatives and additives, therefore, the role of enzymes in potentially replacing the chemicals is very imperative. Application of enzymes in bakery not only enhances the dough properties such as, gas retention, crumb softness, water absorption capacity, and others but improves the nutritional status of products. Microbial sources of enzymes offer multiple advantages over plants and animals. Microbial enzymes from diverse resources have been reported for usage in bread making. A wide array of microbial enzymes viz. xylanases, phytases, α-amylases, proteases, cellulases, glucose oxidases, lipase and others have been reported to enhance the nutritional, sensory and other desirable properties of bread. Current article presents recent developments on application of enzymes for improvement of bread quality.     

Improvement of the quality of wheat bread by addition of glycoside hydrolase family 10 xylanases

Although many xylanases are widely used in the baking industry, only one glycoside hydrolase family 10 (GH 10) xylanase has previously been reported to be effective in baking. In this study, we compared the effectiveness of two GH 10 xylanases, psychrophilic XynA from Glaciecola mesophila and mesophilic EX1 from Trichoderma pseudokoningii, in bread making. The optimal dosages needed to improve wheat flour dough and bread quality were 270-U/kg flour for EX1 and 0.9-U/kg flour for XynA. At their optimal dosage, both XynA and EX1 had significant dough-softening ability, resulting in a 50% reduction in Brabender units. XynA was more effective than EX1 in reducing the time to reach maximum consistency. XynA and EX1 showed similar effects in improving the bread volume (~30% increase). EX1 was more effective in reducing the initial crumb firmness. Although both enzymes exhibited similar anti-staling effects on the bread, based on a decrease in the bread firmness, XynA had a greater effect on reducing the firming rate, and EX1 showed an enhanced reduction in the initial firmness. These results show that these two GH 10 xylanases have unique advantages in improving dough and bread quality and indicate their potential in bread making.     

Effects of High-voltage Electric Field Treatment on the Water Activity of Bread

Treating bread dough by a high-voltage electric field (HVEF) during the first fermentation enabled the bread dough to retain water in the gluten fibers. The microstructure of the gluten fibers was still visible even with an HVEF treatment at 50 kV for 20 min, but could no longer be observed when the gluten was treated for more than 30 min. The crumb temperature of the HVEF treated bread during baking began to rise a few minutes sooner than that of the untreated bread, but the maximum temperature reached was the same in both cases: 99°C. The fact that the water activity of the HVEF-treated bread was 0.987 ± 0.0056, being higher than that of the untreated bread by 0.011, is in good agreement with the growing tests of Rhizopus nigricans. Furthermore, a distinct decrease in the water loss of the baked gluten was observed after the HVEF treatment. These results suggest that the HVEF treatment increased the ability of the gluten fibers, rather than the starch granules, to absorb and retain water; the state of the remaining water is considered to have become immobile, so that migration of moisture to the starch granules in the bread could be minimized.     

Effects of Acidification, Sodium Chloride, and Moisture Levels on Wheat Dough: II. Modeling of Bread Texture and Staling Kinetics

The effect of three experimental factors pH (addition of lactic acid and sodium hydroxide), water, and sodium chloride (NaCl) addition on wheat bread making performance (volume, baking loss, crumb firmness, crumb grain features) and the crumb staling during storage was studied. The staling behavior was modeled with the Avrami equation and with linear regressions. All bread quality parameters were reliably modeled using response surface methodology (up to R ² ?=?0.97). The crumb staling behavior was better described by a linear regression than by the rate constant k of the Avrami equation (R ² ?=?0.87 / R ² ?=?0.36). The highest volume can be achieved with the experimental values pH 5.39, 0.41?g NaCl 100?g^?1 flour and 68.7?g water 100?g^?1 flour. Correlation analysis revealed significant linear dependency of dough rheology (complex shear modulus) on the firmness of the bread crumb (r?=?0.73) and staling attributes (r????0.73). Dough microstructural properties showed significant but low correlation with bread making performance attributes.     

Survival and growth of Bacillus cereus in bread

Bread doughs were artificially inoculated with spores of six Bacillus cereus strains at different inoculum levels and counts of survivors in bread determined during storage at 27.5 degrees C. No B. cereus were isolated from the centre crumb of 400 g loaves when the dough contained less than 10(4) spores/g whereas with 800 g loaves survival occurred with doughs containing 5.0 X 10(3) spores/g. With all strains there was a period of at least 24 h before multiplication took place in the bread. The inclusion in dough of 0.2% of calcium propionate, based on flour, effectively delayed germination and subsequent multiplication of B. cereus spores. It is concluded that the risk of food poisoning due to the presence of B. cereus in bread is minimal.     

The effect of seaweed composite flour on the textural properties of dough and bread

Seaweeds as food and seaweed-derived food flavors, colors, and nutrients are attracting considerable commercial attention. In the baking industries, hydrocolloids are of increasing importance as bread making improvers, where their use aims to improve dough handling properties, increase the quality of fresh bread, and extend the shelf life of stored bread. Seaweeds contain a significant amount of soluble polysaccharides and have the potential function as a source of dietary fiber. In this study, red seaweed (Kappaphycus alvarezii) powder was incorporated (2–8 %) with wheat flour and used to produce bread. The effect of seaweed composite flour on dough rheological properties and the quality of bread was investigated using various techniques. Farinograph tests were applied to determine the effect of seaweed powder on the rheological properties of wheat flour dough, while texture profile analysis (TPA) was used to measure the textural properties of dough as well as the final product. The results showed that the additions of seaweed powder (2–8 %) increased the water absorption of the dough. TPA results showed that the addition of seaweed powder decreased stickiness properties. Bread produced with seaweed composite flour showed higher values of firmness.     

Lactic acid bacteria of the sour cassava starch fermentation

In Brazil and Colombia, 'sour starch' is traditionally obtained by a submerged lactic fermentation of crude cassava starch followed by sun drying. It is used by local bakers to prepare breadlike products which display the same expanded crumb texture as in wheat bread.
In this process, suspended starch is settled down and left aside for a few weeks under anaerobic conditions where natural lactic populations develop.
Three collections of clones isolated from local fermentations have been identified using the API procedure and further characterized. Most of them belong to different species of Lactobacillus . Many display a ropy phenotype, typical for exopolysaccharide (EPS) excretion. A possible role of these EPS in the special properties of sour starch is discussed.     

Diversity of Novel Glutenin Subunits in Bread Wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Glutenin is a major determinant of baking performance and viscoelasticity, which are responsible for high-quality bread with a light porous crumb structure of a well-leavened loaf. We analyzed the diversity of glutenin genes from six wheat cultivars (Korean cvs. Keumgang and Jinpum, Chinese cvs. China-108 and Yeonnon-78, and Japanese cvs. Norin-61 and Kantou-107). Glutenins contain two types of isoforms such as high molecular weight glutenin subunit (HMW-GS) and low molecular weight glutenin subunit (LMW-GS). Glutenin fractions were extracted from wheat endosperm using Osborne solubility method. A total of 217 protein spots were separated on two-dimensional gel electrophoresis with isoelectric focusing (wide range of pH 3–10). The proteins spots were subjected to tryptic digestion and identified by matrix assisted laser desorption/ionization–time of flight mass spectrometry. HMW-GS (43 isoforms) and LMW-GS (seven isoforms) are directly responsible for producing high-quality bread and noodles. Likewise, all the seed storage proteins are digested to provide nutrients for the embryo during seed germination and seedling growth. We identified the diverse glutenin subunits in wheat cultivars and compared the gluten isoforms among different wheat cultivars according to quality. This work gives an insight on the quality improvement in wheat crop.     

Survival and growth of Bacillus cereus in bread

Bread doughs were artificially inoculated with spores of six Bacillus cereus strains at different inoculum levels and counts of survivors in bread determined during storage at 27·5°C. No B. cereus were isolated from the centre crumb of 400 g loaves when the dough contained less than 10⁴ spores/g whereas with 800 g loaves survival occurred with doughs containing 5·0 times 10³ spores/g. With all strains there was a period of at least 24 h before multiplication took place in the bread. The inclusion in dough of 0·2% of calcium propionate, based on flour, effectively delayed germination and subsequent multiplication of B. cereus spores. It is concluded that the risk of food poisoning due to the presence of B. cereus in bread is minimal.     

Odorant transfer characteristics of white bread during baking

The potent odorants in the crust and crumb of white bread were identified and quantified by gas chromatography-mass spectrometry and gas chromatography/olfactometry. The weight loss ratio of the samples baked at 220 °C was controlled in the range of 0-28%. The odorants were classified into 5 types by the transfer characteristics: i) All amounts of odorant transferred from the crust to external space (type-I). ii) All transferred from the crust to the crumb and external space (type-II). iii) Certain amount remaining in the crust and the rest transferred to the crumb and external space (type-III). iv) All transferred from the crumb to external space (type-IV). v) Certain amount remaining in the crumb and the rest transferred to the crust and external space (type-V). The odorants of type-IV were not apparent after the crust had formed. The results indicate that the crust could be a barrier to prevent the odorants from being transferred to external space.     

Microbial ecology and quality assurance in food fermentation systems. The case of kefir grains application

Fermentation technology has become a modern method for food production the last decades as a process for enhancing product stability, safety and sensory standards. The main reason for this development is the increasing consumers’ demand for safe and high quality food products. The above has led the scientific community to the thorough study for the appropriate selection of specific microorganisms with desirable properties such as bacteriocin production, and probiotic properties. The main food products produced through fermentation activity are bread, wine, beer cheese and other dairy products. The microorganisms conducting the above processes are mainly yeasts and lactic acid bacteria. The end products of carbohydrate catabolism by these microorganisms contribute not only to preservation as it was believed years ago, but also to the flavour, aroma and texture and to the increase of the nutritional quality by thereby helping determine unique product characteristics. Thus, controlling the function of specific microorganisms or the succession of microorganisms that dominate the microflora is therefore advantageous, because it can increase product quality, functionality and value. Throughout the process of the discovery of microbiological diversity in various fermented food systems, the development of starter culture technology has gained more scientific attention, and it could be used for the control of the manufacturing operation, and management of product quality. In the frame of this review the presentation of the quality enhancement of most consumed fermented food products around the world is attempted and the new trends in production of fermented food products, such as bread is discussed. The review is focused in kefir grains application in bread production.     

Medical nutrition therapy: use of sourdough lactic acid bacteria as a cell factory for delivering functional biomolecules and food ingredients in gluten free bread

Celiac disease (CD) is an immune-mediated disease, triggered in genetically susceptible individuals by ingesting gluten from wheat, rye, barley, and other closely related cereal grains. Currently, the estimated prevalence of CD is around 1 % of the population in the western world and medical nutritional therapy (MNT) is the only accepted treatment for celiac disease. To date, the replacement of gluten in bread presents a significant technological challenge for the cereal scientist due to the low baking performance of gluten free products (GF). The increasing demand by the consumer for high quality gluten-free (GF) bread, clean labels and natural products is rising. Sourdough has been used since ancient times for the production of rye and wheat bread, its universal usage can be attributed to the improved quality, nutritional properties and shelf life of sourdough based breads. Consequently, the exploitation of sourdough for the production of GF breads appears tempting. This review will highlight how sourdough LAB can be an efficient cell factory for delivering functional biomolecules and food ingredients to enhance the quality of gluten free bread.     

Application of Bifidobacterium strains to the breadmaking process

The possible use of bifidobacterial strains from different origin (adult and infant humans, and chicken) as novel starter cultures for breadmaking was evaluated. Fermentative parameters of doughs (pH, volume, total titrable acidity [TTA], lactic and acetic acids production and rheofermentative parameters) and technological parameters of breads (specific volume, bread shape and crumb hardness) were analyzed. Human bifidobacterial strains could replace Lactobacillus strains, commercialized for breadmaking, as they yielded breads with similar characteristics but with the advantage of having softer crumbs. Important differences between the behavior of chicken bifidobacterial strains and human bifidobacterial strains were found when comparing bread TTA, bread shape and bread volume. Breads made with chicken strains showed significantly lower (p < 0.05) specific bread volume than those made with human strains, while showing similar values of TTA. The effects observed when using bifidobacterial strains from different origin as novel starter cultures for breadmaking seemed to depend on the strain and its origin.     

重组小麦静息巯基氧化酶的表达、酶学特性及其对面包品质的影响

为发展新型面粉改良酶制剂,利用大肠杆菌Escherichia coli原核表达了小麦静息巯基氧化酶(Wheat quiescin sulfhydryl oxidase,wQSOX)。将合成的wqsox基因构建至pMAL-c5x载体,并在大肠杆菌中进行表达,优化蛋白表达条件后对重组蛋白进行分离纯化及融合标签切除,获得的重组wQSOX蛋白用于酶学性质探究以及面包品质改良。结果表明,合成的截短wqsox基因包含1359 bp,编码453个氨基酸,理论蛋白分子量51 kDa;构建的pMAL-c5x-wqsox重组质粒在E.coli Rosetta gamiB(DE3)中可溶表达了重组蛋白MBP-wQSOX,其最佳表达条件为:诱导温度25℃,诱导剂IPTG浓度0.3 mmol/L,诱导时间6 h;利用Xa因子蛋白酶切除了MBP融合标签,亲和层析纯化得到了wQSOX;wQSOX可催化DTT、GSH和Cys氧化,并伴随着H2O2的生成,其中对DTT表现出最高的底物特异性;酶学性质研究发现,wQSOX最适反应温度和pH分别为50℃和10.0,在高温和碱性环境条件下表现出较好的稳定性;每克面粉中添加1.1 U wQSOX能够显著(P<0.05)提高26.4%的面包比容,降低20.5%的面包芯硬度和24.8%的咀嚼性,表现出了较好的改良面包加工品质能力。研究结果对丰富新型面粉改良酶制剂种类以及推动wQSOX在焙烤行业的应用奠定了理论基础。     

Agonistic Interactions and the Distribution of Foraging Organisms: Individual Costs and Social Information

The results of a previous experiment we conducted suggested that agonistic interactions may, counterintuitively, attract organisms to food sites rather than drive them away. In this study we test whether interactions attract or deter organisms by manipulating the distribution of interactions in a natural population of mallard ducks (Anas platyrhynchos L.). We manipulated the distribution of interactions by changing the size of the bread fed to the ducks from two food sites. In the condition with large pieces of bread the distribution of interactions between the two food sites was more extreme than in the small bread condition. The attraction hypothesis predicted that the distribution of ducks should be more extreme in this condition, whereas the deterrence hypothesis predicted that the distribution of ducks should be less extreme. We found that the distribution of ducks was significantly more extreme in the large bread condition. This supports the hypothesis that agonistic interactions act as a net attraction to foraging organisms. The possible benefits organisms may gain from agonistic interactions are discussed.     

Application of novel starter cultures for sourdough bread production

Sourdough application has been extensively increased in the last years due to the consumers demand for food consumption without the addition of chemical preservatives. Several starter cultures have been applied in sourdough bread making targeting the increase of bread self-life and the improvement of sensorial character. More specific, Lactobacillus acidophilus and Lactobacillus sakei as single and mixed cultures were used for sourdough bread making. Various sourdough breads were produced with the addition of sourdough perviously prepared with 10% w/w L. acidophilus, 10% w/w L. sakei and 5% w/w L. acidophilus and 5% w/w L. sakei at the same time. Various chemical parameters were determined such as lactic acid, total titratable acidity and pH. The results revealed that the produced sourdough bread made with sourdough containing the mixed culture was preserved for more days (12 days) than all the other breads produced in the frame of this study, since it contained lactic acid in higher concentrations. The respective total titratable acidity varied between 10.5 and 11 ml NaOH N/10. The same sourdough bread had a firmer texture, better aroma, flavor and overall quality compared to other sourdough breads examined in this study, as shown by sensory evaluation tests and results obtained through SPME GC–MS analysis, which revealed significant differences among the different bread types.     

Kinetics of in Vitro Bread Bolus Digestion with Varying Oral and Gastric Digestion Parameters

The rate of bolus disintegration in the stomach plays an important role in gastric emptying, which has been shown to be directly correlated with post-food consumption blood glucose levels and satiety. This study examined the effect of various oral and gastric factors on bread bolus disintegration, including flour type, hydrodynamic forces, saliva level, and presence of α-amylase. The kinetics of bolus disintegration were determined by measuring the mass retention of boluses and fitting their disintegration profiles to a linear-exponential model. Artificially masticated bread was mixed with simulated saliva to form a bolus, which was soaked in simulated gastric juice for 120 min. The mass retention kinetics during static and agitated soaking followed three distinct profiles: exponential, sigmoidal, and delayed sigmoidal. The differences in profiles were attributed to varying levels of water absorption, caused by variations in bread structure and moisture content. Increasing the bolus saliva level decreased cohesive forces and increased bolus disintegration rate. These changes could have been caused by the increase of water inside the food matrix, or by the softening effect of α-amylase, which was shown to have a significant effect on bolus texture and also caused an increase in bolus disintegration. This work studies the driving factors in the breakdown of different types of bread during simulated gastric digestion. Our results demonstrate that bread structure and moisture content are key features controlling the rate of bread breakdown during gastric digestion.     

Yeasts in foods and beverages: impact on product quality and safety

The role of yeasts in food and beverage production extends beyond the well-known bread, beer and wine fermentations. Molecular analytical technologies have led to a major revision of yeast taxonomy, and have facilitated the ecological study of yeasts in many other products. The mechanisms by which yeasts grow in these ecosystems and impact on product quality can now be studied at the level of gene expression. Their growth and metabolic activities are moderated by a network of strain and species interactions, including interactions with bacteria and other fungi. Some yeasts have been developed as agents for the biocontrol of food spoilage fungi, and others are being considered as novel probiotic organisms. The association of yeasts with opportunistic infections and other adverse responses in humans raises new issues in the field of food safety.