Taste of Bread: From Theory to Practice

September 5, 2016 | Food Science

AnalyticBreadAromas

In order to illustrate the method of taste analysis shown above, with actual examples, five representative types of bread could be made.

  • Directly made bread, 3-hour program.
  • Retarded proofing (14 hours at 50°F).
  • Directly made bread, 3-hour program with the addition of 2% strongly acidic dehydrated fermented rye flour.
  • Round loaf with raising agent, retarded proofing using 5% of ready-to-use liquid raising agent with guaranteed minimum bio-cultures.
  • Country-style bread with 20% liquid raising agent with variable bio-cultures.

These different types of breadmaking were chosen in order to study three parameters and their interactions:

  • The type of acidification (dehydrated fermented flour versus raising agent)
  • The length of fermentation (direct versus retarded proofing)
  • The quality of raising agent (raising agent with variable biomass versus raising agent with guaranteed minimum biomass)

After tasting by the qualified panel a statistical analysis (Analysis of Main Ingredients—AMI) was carried out in order to identify groups of homogeneous products. The AMI represents a diagrammatic projection of products/descriptions. The two axes are linear combinations of evaluated sensory descriptions.

This first analysis isolated 2 homogeneous groups which were reanalyzed with sensory analysis and then with olfactometric analysis:

  • A group of “non-acidic/slightly acidic” bread: directly baked bread, retarded proofing bread, bread with dehydrated fermented flour.
  • A group of “more acidic” bread: bread made with guaranteed minimum biomass raising agent, bread made with variable biomass raising agent, bread with dehydrated fermented flour.

The AMI shows that the bread made with dehydrated fermented flour has intermediate characteristics. It was therefore included in each of the two groups for detailed analyses.
 

AC_LessAcidicBreads

Group of “non-acidic or slightly acidic” bread

The “Analytical Approach to Bread Aromas” table shows that physicochemical analysis is not very relevant for this type of product. Only sensory analysis and olfactometric analysis are useful.

  • The directly baked bread has a characteristic “yeasty/fermented” aroma, typical of this type of breadmaking and often much appreciated. With olfactometric analysis, we have been able to show that this aroma mainly comes from a few molecules arising from the metabolism of the yeast, such as 2 methyl-1-butanol (fermented, wine) 3 methyl- 1-butanol (whiskey, malt) and phenylethanol (rose, wine).
  • In the bread made with dehydrated fermented flour, one also finds an acidic character. Moreover, the rye aroma is very evident. However, the color of the bread is significantly darker. The aromatic type is therefore easily recognizable.

In the olfactometric analysis, one finds that in the presence of dehydrated fermented flour the above-mentioned aromatic components are still present in similar quantities. Nevertheless, several other molecules were also detected in the analysis in addition to acetic acid:

  • Isobutyric, isovaleric and butyric acids, lactate of ethyl and octanoate of ethyl; traces of fat and butter
  • Benzaldehyde, furfural: grilled traces
  • Phenylacetaldehyde: honey traces

These new molecules were able to “mask” the perception of the “yeast” odor. The bread made with yeast with a retarded proofing program also allowed the transformation of this yeasty type into a more cereal-like white flour note. The olfactometric analysis shows that the dominant aromatic molecules in the direct baking program are metabolized into a great variety of molecules which give this “cereal” note.

In the “non-acidic or slightly acidic” breadmaking, we have illustrated two ways of improving bread flavors:

  • The addition of aromatizing products gives a typical flavor, even with a small quantity of additive and masks the “yeasty” notes (in our example a dehydrated fermented flour revealed an acidic taste);
  • The lengthening of fermentation (in this case by retarded proofing) transforms the “yeasty” note into a “cereal” note and improves the texture and therefore the aromatic intensity.

Group of “more-acidic” bread

In this group of products the physicochemical analysis makes complete sense:

  • The bread with dehydrated fermented flour and the bread with variable biomass raising agent are equivalent in terms of pH (approx. 4.67), but the latter attains 3 times greater concentrations of acetic (0.6 compared to 0.2 g/kg). This difference translates into a much clearer perception of acidity in the sensory analysis;
  • In this breadmaking program, only the bread made with the minimum guaranteed biomass reaches the specifications of the “Bread Law” (bread pH 0.9 g/kg of bread) with concentrations of lactic acid and acetic acid respectively 3.5 and 2 times greater than those for bread made with variable biomass raising agent.

The physicochemical analysis is completed by sensory and olfactory analyses.

In this new frame of reference the “pain sur levain,” i.e. the bread made with dehydrated fermented flour, is less aromatic (“white flour” description) and the “acidic” note disappears. The bread made with the raising agent with the minimum guaranteed biomass has the strongest aromas of “vinegar,” “rye” and “persistent taste.” It also has a darker color and a much more irregular texture. This is a typical traditional type bread, clearly made with a “raising agent.“

Through olfactometric analysis of the bread made with the guaranteed minimum biomass, we found a significant amount of acetic acid and various molecules:

  • Acetate of ethyl, acetate of isoamyl, p-cimene: fruity notes
  • 2-pentyl furan, saturated fatty acids from C6 to C9: buttery
    and cheesy notes
  • Furfural and furfurylic alcohol: grilled notes

All these molecules contribute to the aromatic richness of bread made with a raising agent.
 

AC_MoreAcidicBreads

The bread baked with the variable biomass raising agent was also interesting in terms of taste. The sensory evaluation showed evidence that its dominant aromas were “honey” and “cereal” and that overall it was less acidic. The texture was more regular and the bread was lighter in color. It is an interesting aroma but it does not have the characteristic notes of bread made with raising agent.

In the group of bread made “with a raising agent,” the bread with dehydrated fermented flour stood out immediately through its lack of richness and aromatic intensity.

Comparison of the two breads made with raising agents showed clear evidence of the need to combine a raising agent with a guaranteed minimum biomass and a long fermentation in order to achieve the richness and aromatic intensity of real bread made with raising agents, as well as consistency in the mouth, characteristic texture and good keeping properties.

The bread that we have chosen to illustrate the analytic exploration of bread flavors are just one example among others. We could have chosen to examine other characteristics:

  • Development of the aroma created by raising agents with variable biomass of various ages.
  • The aromatic diversity of bread made with raising agents with a guaranteed minimum biomass according to various breadmaking programs.
  • A comparison of the aromatic contribution of dehydrated fermented flours and liquid fermented flours.
  • The aromatic diversity of bread made = from starter cultures based raising agents, with variable flora.
  • A comparison with a bread with natural raising agents or a bread with a raising agent with guaranteed minimum biomass decrease in salt by using yeast derivatives.

The list could be even longer! These analytic disciplines are revolutionizing the approach to taste in breadmaking.

Two means of generating taste

The different breadmaking methods described here highlight the two complementary ways of generating taste in breadmaking:

  • The addition of flavor-enhancing products adds taste without changing the breadmaking method. These products clearly typify the bread but they do not give it the aromatic richness of products that have an active fermentation, even when they are added in very large quantities (raising agent with variable biomass).
  • The combination of fermentation agents and long maturation results in the aromatic richness of traditional bread but requires more complex production methods.

These two methods—practicality and long fermentation—are not contradictory. Sensory analysis clearly shows that each of them produces its own aromatic type. Rather than being opposites, they bring diversity.

Conclusion

In this series, Taste of Bread, bread has frequently been compared to wine and cheese. It is true that what these three foodstuffs have in common is that fermentation plays an essential part in their development, particularly in the synthesis of their aromas. Bread, which is a basic nutritional staple when buying power is low, becomes an accompaniment when the standard of living rises. For some time now, rather than being an “essential,” bread and the “pleasure” derived from its taste have been considered as accessories—unlike its two brothers, wine, and cheese, which have always been discussed and appreciated in generous terms. We love to talk about our past experiences, our new discoveries and our special moments.

With the huge selection now offered, bread has become a food of character and has confirmed its right to be the center of interest. It is not just “tasted” with cheese but agreeably complements most foods. It can even be eaten on its own, just for pleasure! Bread has become highly valued due to the development of technique. Scientists, industrial manufacturers, and craftsmen all work together to satisfy the tastes of a more knowledgeable and more demanding clientele who love both tradition and experimentation. These days, the art of making tasty bread can be pursued with a large palette of different resources.

Physicochemical analytical tools, an understanding of bread flora and mastery of the production of live microorganisms enable us to offer bakers products that guarantee performance, are easy to use, reliable and safe so that they can create quality bread with excellent taste, but also with a good shelf life, texture, and appearance. It is up to bakers to make full use of their creative talents and skills, and up to scientists and manufacturers of fermentation agents to give them the tools that they need. It is in pursuit of this logic and in this environment that Lesaffre can carry on with the development of their products and techniques, motivated by: “the cultivation of taste in breadmaking.”

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