Minimierung von Kochsalz bei Brot und Backwaren: Technologie und Geschmackqualität IGF-Projekt Nr N

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1 .7. Minimierung von Kochsalz bei Brot und Backwaren: Technologie und Geschmackqualität IGF-Projekt Nr. 5 N Peter Köhler, Katharina Konitzer, Tabea Wieber, Thomas Hofmann Deutsche Forschungsanstalt für Lebensmittelchemie, Lise-Meitner-Straße, 55 Freising Technische Universität München, Lehrstuhl für Lebensmittelchemie und Molekulare Sensorik, Lise-Meitner- Straße, 55 Freising 5. September Joint Project on Salt Reduction in Bread Chair of Brewing and Beverage Technology, Technical University of Munich Margit Beck, Mario Jekle and Thomas Becker Technological issues of sodium chloride in bread German Research Centre for Food Chemistry Tabea Wieber and Peter Köhler Sodium binding in bread, influence of constituents Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich Katharina Konitzer and Thomas Hofmann Sensory evaluation of bread, replacers, model experiments

.7. Health Issues Excess intake of sodium: primary cause of hypertension cardiovascular diseases (leading cause of mortality

arterial hypertension current intake (Western Europe, US) recommended intake (WHO) g salt/day 5 g salt/day ( g sodium/day) ( g

5 % (based on flour) Lit: He and MacGregor, 7; WHO, 7; National Nutrition Survey II, Salt Reduction Strategies Salt

Stepwise reduction Technological methods encapsulated salt crystals, inhomogeneous distribution So far no strategy is entirely

2 .7. Health Issues Excess intake of sodium: primary cause of hypertension cardiovascular diseases (leading cause of mortality worldwide) particular risk for -5 % of the population which suffer from salt-sensitivity: excess sodium intake leads to arterial hypertension current intake (Western Europe, US) recommended intake (WHO) g salt/day 5 g salt/day ( g sodium/day) ( g sodium/day) Bread/cereal products provide % of daily sodium intake in Germany Average NaCl levels in German bread:.5.5 % (based on flour) Lit: He and MacGregor, 7; WHO, 7; National Nutrition Survey II, Salt Reduction Strategies Salt replacement potassium chloride, calcium and magnesium salts, citrates, gluconates Salt enhancement L-lysine, L-arginine Stepwise reduction Technological methods encapsulated salt crystals, inhomogeneous distribution So far no strategy is entirely satisfactory Lit: Kilcast and Angus, 7; Girgis, ; Salovaara, 9; Wyatt, 9; Takano, ; Charlton, 7; patents WO / 9; WO 7/5 A; US 9/97 A; US 9/9957; WO /959; WO 9/9

.7. Functions of NaCl in Bread Technological functions strengthening of gluten regulation of yeast activity prolongation of shelf life Sensory functions unique, clean salty taste improvement of the

3 .7. Functions of NaCl in Bread Technological functions strengthening of gluten regulation of yeast activity prolongation of shelf life Sensory functions unique, clean salty taste improvement of the entire flavor musty/stale flour/water musty/stale flour/water yeasty sweet salty bitter acidic % NaCl.7 % NaCl sweet salty acidic Fundamental studies on salt taste perception in bread crumb as a basis for new salt reduction strategies yeasty bitter.5 % NaCl. % NaCl Lit.: Kilcast and Angus, 7 5 Aims Reduction of the sodium content in bread and baked goods Studies on the technological effects of sodium chloride Investigation of the parameters affecting salt taste perception in bread crumb Sodium binding to wheat proteins Sodium release from bread crumb during mastication Sodium distribution Texture Identification of new strategies to reduce sodium chloride in bread while maintaining taste quality

.7. Confocal Laser Scanning Microscopy of Wheat Dough % NaCl % NaCl % NaCl Without NaCl: Less interconnected protein structures Sodium chloride

Formation of a protein network Optimal mixing time [min] 7 5 NaCl amount [g NaCl g - flour] 7 Bread volume g - flour [ml g - ] Technological Effects of

... Rate of bread staling [-] Maximal bread volume at.

4 .7. Confocal Laser Scanning Microscopy of Wheat Dough % NaCl % NaCl % NaCl Without NaCl: Less interconnected protein structures Sodium chloride neutralizes the electrostatic repulsion of gluten particles Improved aggregation of gluten molecules Consequence: Increase of the mixing time With NaCl: Formation of a protein network Optimal mixing time [min] 7 5 NaCl amount [g NaCl g - flour] 7 Bread volume g - flour [ml g - ] Technological Effects of NaCl on Baked Goods 5 NaCl amount [g NaCl g - flour] Initial crumb firming [N] 5 NaCl amount [g NaCl g - flour].... Rate of bread staling [-] Maximal bread volume at.5 g NaCl g - flour Decrease of loaf volume at high NaCl concentration Crumb firmness increases in particular with NaCl amounts > g NaCl g - flour lower water-activity leads to an increased rate of bread staling Osmotic effect lowers yeast activity less and smaller crumb pores initial crumb firmness is increased

.7. Crumb Porosity Area of pores [%]. % NaCl.

unstable, weak crumb 5 Amount of pores [-] Area of pores [%].

fluffy, attractive crumb 5 Amount of pores [-] Area of pores

compact crumb 5 Amount of pores [-] 9 Perception of

water with the same ( % NaCl, s) amount of NaCl aqueous salt

5 .7. Crumb Porosity Area of pores [%]. % NaCl. porosity: large irregular. unstable, weak crumb 5 Amount of pores [-] Area of pores [%]..5% NaCl porosity:. normal regular. fluffy, attractive crumb 5 Amount of pores [-] Area of pores [%]..5% NaCl porosity:. very fine dense. compact crumb 5 Amount of pores [-] 9 Perception of Saltiness: Bread vs. Water -AFC-test g bread crumb vs. water with the same ( % NaCl, s) amount of NaCl aqueous salt solution tastes significantly saltier (α =.) Why? aqueous solution: % of sodium is instantly available in the mouth bread crumb: What percentage is available in the mouth? 5

6 .7. Sodium Binding to Wheat Proteins Sodium bound to protein [mg/g] ph 7 ph 9. Albumins (MB) Albumins/Globulins (ISE) Gliadins (ISE) Glutenins (ISE) More sodium is bound to wheat proteins at ph 9 than at ph 7 Explanation: acidic amino acid residues are involved in the binding of sodium ions Sodium Binding to Proteins Sensory Impact Calculation of the corresponding amounts of NaCl in wheat bread: Sodium bound at ph 7 [mg/g protein] NaCl in bread (based on flour) [%] Albumins (MB).7 <. Albumins/Globulins (ISE). <. Gliadins (ISE).. Glutenins (ISE). <. But:. % NaCl is the lowest detectable difference, when bread containing % NaCl is used as a reference The binding of sodium to wheat proteins is negligible concerning the sensory perception of saltiness

.7. Sodium Release Discontinuous Methods In-mouth g bread crumb Mastication simulator (Potter S Homogenizer) g bread crumb Addition of human saliva Chewing (5- s) Chewing (5- s, 7 C) Spit out, weigh

7 .7. Sodium Release Discontinuous Methods In-mouth g bread crumb Mastication simulator (Potter S Homogenizer) g bread crumb Addition of human saliva Chewing (5- s) Chewing (5- s, 7 C) Spit out, weigh Centrifugation ( min, rpm) Dilution of the supernatant with buffer Quantitation of sodium: Sodium-selective electrode (ISE) Sodium Release Results (Discontinuous) Time-resolved release of sodium from bread (.5 % NaCl) in-mouth or in the mastication simulator (human saliva, probands): Extracted sodium[%] 5 s s 5 s s s Duration of chewing Bread (Mouth) Bread (Mastication simulator) Sodium is completely extractable from bread crumb after 5 s (simulator) and s (mouth) The release of sodium is slower in-mouth than in the simulator due to different homogenization 7

.7. Sodium Release Continuous Method Motor Chewing Satin ribbon Absorption of saliva during chewing of g bread crumb by a satin ribbon (width: mm) Ribbon is cut into small pieces (5.

8 .7. Sodium Release Continuous Method Motor Chewing Satin ribbon Absorption of saliva during chewing of g bread crumb by a satin ribbon (width: mm) Ribbon is cut into small pieces (5.7 cm = 5 s) Extraction with 5 ml 5 % TISAB (TRIS-buffer ph 7, 5 min Vortex) Quantitation of sodium by ISE 5 Sodium Release Results (Continuous) Bread crumb with.5 % NaCl:. Sodium concentration in saliva Saliva secretion Sodium in saliva [mg/ml] Duration of chewing [s] Saliva [ml] Duration of chewing A,5 % B,5 % A,5 % B,5 % Higher sodium concentrations in the saliva of panellist B Explanation: lower saliva secretion in the mouth of panellist B

9 .7. Sodium Release Results (Continuous) Bread crumb with.5 % NaCl:. Sodium concentration in saliva Sodium concentration * saliva secretion Sodium in saliva [mg/ml] Duration of chewing [s] Sodium in saliva [mg] Duration of chewing [s] A,5 % B,5 % A,5 % B,5 % Corresponding absolute amounts of extracted sodium Complete sodium extraction at the earliest after 55 s (. mg Na)! g bread crumb (.5 % NaCl) contain. mg Na lower sodium concentration at the sampling point 7 Discontinuous vs. Continuous Method Sodium release from bread crumb with.5 % NaCl: Extracted sodium [mg] Discontinuous method Sodium in saliva [mg] Continuous method 5 s s 5 s s s Duration of chewing Duration of chewing [s] A,5 % B,5 % A,5 % B,5 % Continuous method: slower sodium release than the discont. method Explanation: Continuous method: chewing point sampling point Discontinuous method: additional extraction by centrifugation 9

.7. Sodium Distribution Fine-/Coarse-grained Salt reference (homogeneous) coarse

dry matter] 9 7 5 5 s s 5 s s s Duration of chewing P coarse-grained NaCl P

bread with coarse-grained NaCl Salt taste is enhanced through higher sodium

10 .7. Sodium Distribution Fine-/Coarse-grained Salt reference (homogeneous) coarse NaCl (inhomogeneous) fine salt (patent blue V) coarse salt (patent blue V) addition at min addition at 7.5 min 9 Sodium Distribution Salt Taste and Na + Release signif. saltier (-AFC-test, α =.) coarse NaCl (inhomogeneous) reference (homogeneous) Extracted sodium [mg/g crumb dry matter] s s 5 s s s Duration of chewing P coarse-grained NaCl P coarse-grained NaCl P homogeneous P homogeneous Faster sodium release from the bread with coarse-grained NaCl Salt taste is enhanced through higher sodium availability and sensory contrast Addition of coarse NaCl (inhomogeneous sodium distribution) enables a sodium reduction by 5 % without adverse effects of the sensory quality Lit: Meiselman and Halpern, 97; Busch et al., 9; Noort et al.,

.7. Texture Fine-/Coarse-Pored Bread Crumb Variation of proofing times / min bread without proofing reference bread with normal proofing (/ min) 9/ min bread with very long

) tasted significantly saltier than / min (at a constant weight and at a constant volume) Texture Sodium Release: / min vs.

(/ min) mouth (9/ min) mastication simulator (9/ min) faster sodium release from the 9/ min-bread in accordance with sensory analysis: 9/ min-bread tasted sign.

11 .7. Texture Fine-/Coarse-Pored Bread Crumb Variation of proofing times / min bread without proofing reference bread with normal proofing (/ min) 9/ min bread with very long proofing Sensory analyses (-AFC tests, all breads contained.5 % NaCl): 9/ min and reference (resp.) tasted significantly saltier than / min (at a constant weight and at a constant volume) Texture Sodium Release: / min vs. 9/ min Extracted sodium [mg] Time-resolved sodium release during mastication: Constant sample weight ( g): 5 s s 5 s s s Duration of chewing mouth (/ min) mastication simulator (/ min) mouth (9/ min) mastication simulator (9/ min) faster sodium release from the 9/ min-bread in accordance with sensory analysis: 9/ min-bread tasted sign. saltier Extracted sodium [mg] Constant sample volume (/ min: ca. g, 9/ min: ca. g): 5 s s 5 s s s Duration of chewing mouth (/ min) mastication simulator (/ min) mouth (9/ min) mastication simulator (9/ min) amount of sodium is similar at the beginning no explanation for the sensory analysis: 9/ min-bread still tasted sign. saltier

12 .7. Texture Correlations to Pore Size & Na + Release average pore size [pixel²] / min reference 9/ min texture [N/g] average pore size [pixel²] / min reference 9/ min extracted sodium [%] average size texture average size extracted sodium (in-mouth, 5s) 9/ min: largest pores, softest texture 9/ min: highest amount of extracted sodium after 5 s / min and reference: similar extracted amounts of sodium, but the reference tasted saltier Salt perception in bread crumb is influenced by a combination of sodium release and texture Conclusion Sodium chloride has important technological effects in bread The salt intensity of bread crumb is impaired by: a retarded sodium release during chewing texture-induced tactile-gustatory interactions in mouth or brain The salt intensity of bread crumb can be enhanced by an accelerated sodium release during chewing an inhomogeneous distribution of sodium a modification of crumb texture Suitable approaches to reduce NaCl in wheat bread: coarse-pored crumb coarse-grained NaCl (reduction of sodium by 5 %)

13 .7. Thanks... for the financial support of this research project (AiF 5 N) by the FEI (Forschungskreis der Ernährungsindustrie e.v., Bonn), the AiF and the Ministry of Economics and Technology... and to you for your attention! 5

SODIUM REDUCTION WHILE MAINTAINING SENSORY PROFILES. Martijn Noort, Ronald Visschers November 29 th, Bern

SODIUM REDUCTION WHILE MAINTAINING SENSORY PROFILES Martijn Noort, Ronald Visschers November 29 th, Bern TNO mission and summary TNO aligns knowledge and people to create innovations to enhance the competitive