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.     

FLAVOR PROPERTIES OF PLAIN SOYMILK*

A trained sensory panel was used to (1) establish terminology for describing flavor attributes of a wide range of “fresh” and processed soymilks (SMs); and (2) test the lexicon and describe the flavor properties of a wide range (n = 32) of plain SM samples. Twenty‐eight attributes were identified in the SMs studied. However, findings indicate that the main differences are a consequence largely of the presence of certain attributes that are either infrequently present or unique to a specific product. Thus, sensory evaluation of SM needs to include a review of samples to ensure that all attributes are documented prior to evaluation, or use a method that allows the addition of attributes during testing.     

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.     

In situ production of exopolysaccharides during Sourdough fermentation by cereal and intestinal isolates of lactic acid bacteria

EPS formed by lactobacilli in situ during sourdough fermentation may replace hydrocolloids currently used as texturizing, antistaling, or prebiotic additives in bread production. In this study, a screening of >100 strains of cereal-associated and intestinal lactic acid bacteria was performed for the production of exopolysaccharides (EPS) from sucrose. Fifteen strains produced fructan, and four strains produced glucan. It was remarkable that formation of glucan and fructan was most frequently found in intestinal isolates and strains of the species Lactobacillus reuteri, Lactobacillus pontis, and Lactobacillus frumenti from type II sourdoughs. By the use of PCR primers derived from conserved amino acid sequences of bacterial levansucrase genes, it was shown that 6 of the 15 fructan-producing lactobacilli and none of 20 glucan producers or EPS-negative strains carried a levansucrase gene. In sourdough fermentations, it was determined whether those strains producing EPS in MRS medium modified as described by Stolz et al. (37) and containing 100 g of sucrose liter(-1) as the sole source of carbon also produce the same EPS from sucrose during sourdough fermentation in the presence of 12% sucrose. For all six EPS-producing strains evaluated in sourdough fermentations, in situ production of EPS at levels ranging from 0.5 to 2 g/kg of flour was demonstrated. Production of EPS from sucrose is a metabolic activity that is widespread among sourdough lactic acid bacteria. Thus, the use of these organisms in bread production may allow the replacement of additives.     

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.     

Evaluation of mono or mixed cultures of lactic acid bacteria in type II sourdough system

The aim of this study was to evaluate the use of mono and mixed lactic acid bacteria (LAB) cultures to determine suitable LAB combinations for a type II sourdough system. In this context, previously isolated sourdough LAB strains with antimicrobial activity, which included Lactobacillus plantarum PFC22, Lactobacillus brevis PFC31, Pediococcus acidilactici PFC38, and Lactobacillus sanfranciscensis PFC80, were used as mono or mixed culture combinations in a fermentation system to produce type II sourdough, and subsequently in bread dough production. Compared to the monoculture fermentation of dough, the use of mixed cultures shortened the adaptation period by half. In addition, the use of mixed cultures ensured higher microbial viability, and enhanced the fruity flavor during bread dough production. It was determined that the combination of L. plantarum PFC22 + P. acidilactici PFC38 + L. sanfranciscensis PFC80 is a promising culture mixture that can be used in the production of type II sourdough systems, and that may also contribute to an increase in metabolic activity during bread production process.     

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.     

Prebiotic Content of Bread Prepared with Flour from Immature Wheat Grain and Selected Dextran-Producing Lactic Acid Bacteria

In the last few years the need to produce food with added value has fueled the search for new ingredients and health-promoting compounds. In particular, to improve the quality of bakery products with distinct nutritional properties, the identification of new raw materials, appropriate technologies, and specific microbial strains is necessary. In this study, different doughs were prepared, with 10% and 20% flour from immature wheat grain blended with type “0 America” wheat flour. Immature flour was obtained from durum wheat grains harvested 1 to 2 weeks after anthesis. Doughs were obtained by both the straight-dough and sourdough processes. Two selected exopolysaccharide-producing strains of lactic acid bacteria (LAB), Leuconostoc lactis A95 and Lactobacillus curvatus 69B2, were used as starters. Immature flour contained 2.21 g/100 g (dry weight) of fructo-oligosaccharides. Twenty percent immature flour in dough resulted in a shorter leavening time (4.23 ± 0.03 h) than with the control and dough with 10% immature flour. The total titratable acidity of sourdough with 20% immature flour was higher (12.75 ± 0.15 ml 0.1 N NaOH) than in the control and sourdough with 10% immature wheat flour (9.20 ml 0.1 N NaOH). Molecular analysis showed that all samples contained three LAB species identified as L. lactis, L. curvatus, and Pediococcus acidilactici. A larger amount of exopolysaccharide was found in sourdough obtained with 20% immature flour (5.33 ± 0.032 g/kg), positively influencing the exopolysaccharide content of the bread prepared by the sourdough process (1.70 ± 0.03 g/kg). The addition of 20% immature flour also led to a greater presence of fructo-oligosaccharides in the bread (900 mg/100 g dry weight), which improved its nutritional characteristics. While bread volume decreased as the concentration of immature wheat flour increased, its mechanical characteristics (stress at a strain of 30%) were the same in all samples obtained with different percentages of fructo-oligosaccharides. These data support the use of immature wheat grain flour, and exopolysaccaride-producing lactic acid bacteria in formulating functional prebiotic baked goods whose nutritional value can be suitably improved.     

DEVELOPMENT OF A LEXICON FOR BEEF FLAVOR IN INTACT MUSCLE

ABSTRACT

A lexicon describing the flavor characteristics of beef across different cuts, grades, and cooking temperatures and methods was developed. Four major cuts of the United States Department of Agriculture (USDA) quality grade beef were cooked to five endpoint temperatures using braising, broiling (oven broiling and electric charbroiling), roasting and grilling (indoor and outdoor grilling). Six highly trained panelists identified and defined a total of 38 aroma and flavor characteristics in 176 beef samples. Beef identity, brown/roasted, bloody/serumy, metallic, fat‐like, overall sweet, sour aromatics and five tastes were present in practically all samples. Other attributes were present only in certain samples, depending on either the sample group or the cooking method/endpoint temperature combination used. This lexicon potentially offers the beef industry a standard tool to identify and quantify flavor attributes as impacted by temperature, cooking method, aging process, storage time, diet regime, packaging, USDA quality grades, etc.

PRACTICAL APPLICATIONS

Until now, the beef industry's main focus has been to assess beef tenderness and juiciness, with an emphasis on ways to improve beef texture. Meat companies and academic institutions have been using the 1995 American Meat Science Association guidelines to assess the flavor of beef, which are not comprehensive. Recent work has focused on flavor, and the industry needs a standardized flavor lexicon that can be used for many projects. It is important for the industry to be able to systematically identify and quantify flavor attributes that drive consumer acceptance.     

The effect of sourdough and calcium propionate on the microbial shelf-life of salt reduced bread

The consumption of low-salt bread represents an efficient way to improve public health by decreasing cardiovascular health issues related to increased intakes of sodium chloride (NaCl). The reduction of NaCl influences the bread quality characteristics, in particular the shelf-life. Calcium propionate (CP) is commonly used in bread as an antifungal agent. Alternatively, sourdough can be used as a natural preservative. This work addresses the feasibility of NaCl reduction in wheat bread focussing on shelf-life and the compensation using sourdough as well as chemical preservatives. The impact of NaCl reduction and the addition of preservative agents in conjunction with different NaCl concentrations on the shelf-life of bread were tested under 'environmental' conditions in a bakery as well as using challenge tests against selected fungi. The challenge tests were performed using fungi commonly found in the bakery environment such as Penicillium expansum, Fusarium culmorum and Aspergillus niger. NaCl reduction decreased the shelf-life by 1-2?days. The addition of sourdough with antifungal activity prolonged the shelf-life to 12-14?days whereas the addition of 0.3?% calcium propionate prolonged the shelf-life to 10-12?days only. The fungal challenge tests revealed differences in the determined shelf-life between the different fungi based on their resistance. Similar antifungal performance was observed in sourdough breads and calcium propionate breads when tested against the different indicator moulds. The findings of this study indicate that addition of sourdough fermented using a specifically selected antifungal Lactobacillus amylovorus DSM 19280 can replace the chemical preservative calcium propionate addition and compensate for the reduced level and, therefore, guarantee the product safety of low-salt bread.