Can salt be reduced without affecting pleasantness of foods

1. Can salt be reduced without affecting pleasantness of foods Katariina Roininen May 29, 2007

3. Anatomy of gustation • In mammals sensory receptor cells are located in taste buds • Taste buds are located in papillae in tongue (4600) and throughout the oral cavity (2500) http://www.cf.ac.uk/biosi/starff/jacop/teaching/sensory/taste.html

4. Taste transduction of salt taste • Salt taste • Sodium Chloride (Na+ Cl- ) • Na+ ions enter the receptor cells via Na-channels • The entry of Na+ causes deporarization, Ca2+ enters through Ca2+-channels causing transmitter release and finally increase firing of afferent nerve http://www.cf.ac.uk/biosi/starff/jacop/teaching/sensory/taste.html

5. Salt perception • Depends on the matrix • B detection threshold • C recognition threshold • D terminal threshold water food Perceived saltiness • Detection threshold for salt • water 0.007% • bread 0.05% A B C D D % NaCl

6. NaCl Salt in foods Preservation Processability Flavour Increases shelf life Increase pleasantness Improves texture Enhance flavours Water-holding capacity Reduce the perception of other stimuli Effect on gluten deve- lopment

7. Use habit Diet Age Gender Salt preference

8. Salt preference • It is only partly innate (compared to sweetness which is innate ) • Preference develops during fist four months • Early imprinting • Experience • Habit • Can be changed • Difficult and takes time • In the beginning low salt food does not meet expectations • Exposure • Increased liking of low salt options

9. Why salt should be reduced? • The association between excessive sodium intake and the development of hypertension • Hypertension is major risk factor in the development of cardiovascular disease • Study of Appeal et al. (1997) showed a graded linear relation between salt intake and blood pressure • It has been estimated that reducing salt intake to 6g a day • Effect on blood presure, could lead to a 24% reduction in deaths from strokes and an 18% reduction in deaths from coronary heart disease, • The cost of CVD to the EU economy is estimated €169B (Petersen et al. (2005)

10. Salt intake • Salt intake in Finland in 2002 was about 9.5 g/day in men and 7 g/day in women • Recommendation in Finland is 7 g/day for men and 6 g/day for women • General recommendations in many EU-countries is 6g/day • In Sweden recent study showed that men aged between18-20 years had a very high salt intake (around 11.7 g/day) • Physiological need is only 2 g/day • Intake should be lowered to meet recommendations Sources of salt, Reinivuo et al. 2006

11. Potential approaches for salt reduction Salt replacers Stepwise reduction Salt enhancers Modification of physical form of salt

12. Effects of salt reduction • Effect depends on the food matrix • Has to take into account Cohesiveness of sausage is decreased Bread will be crumbly Taste and aroma balance will change

13. Mineral salts KCl and MCl2 Salt replacement Umami: Natriumglutamate + 5-ribonucleotides Spices and herbs Increased acidity Salt at the top of the product

14. Salt replacement Mineral salts • Do not deliver the clean salt taste of sodium chloride (NaCl) • The bitterness associated with potassium chloride (KCl) at the concentrations needed for saltiness limits the industrial use • 50:50 NaCl:KCl is blend is common limit • Ruusunen et al. (2005) suggested in a review that the use of mineral salt mixtures is a good way to reduce sodium content in meat products • Gelabert et al. 2003 studied the effect of substituting NaCl by KCl, potassium lactate (K-lactate) and glycine (0-40%) on sensory, microbiological and physiochemical characteristics of fermented sausages • The partial substitution (above 40%) of NaCl with different mixtures of KCl/glycine and K-lactate/glycine had important flavour and textural defects, therefore level of substitution can not increased

15. Salt replacement Commercial mixtures of NaCl and KCl • Pansalt® • Almost half of the sodium is removed and replaced with potassium chloride (KCl), magnesium sulphate (MgSO4) and the essential amino acid L-lysine hydrochloride • Sodium is reduced 43% • Relative saltiness compared to salt (NaCl) is 70% • Problem with bitterness of potassium and magnesium • Morton Lite Salt ®(mixture of NaCl:KCl in relation 60:40) • AlsoSalt (KCl and L-lysine) processed in a way that bitterness is reduced • Adsalt Lo (KCl-NaCl mixture where 13.6% K and 35%Na) • Sub4salt (Na-glukonate+NaCl+KCl) should give 25-50% reduce in sodium • Lo ®Salt (66,6% KCl and 33.3% NaCl) • Saxa So-low salt, Nalow www.pansuola.fi, www.alsosalt.com/potassium1.html, www.mortonsalt.com/consumer/products/foodsalts/litesalt.html, www.losalt.com, www.askadams.co.uk/news_archive2.html

16. Salt replacement Spices and herbs • Marjoram, allspice, onion and monosodium glutamate was added to bouillon (Tuorila et al. 1990) • No effect of the pleasantness of the low salt bouillon • Bouillon with 1% of salt was the pleasant with or without herbs anc spices

17. Salt replacement Increasing sourness • Tomato juice (Pangborn & Trabue 1967) sourness increased perceived saltiness • Rye bread (Helleman 1991) sourness enhanced perceived saltiness clearly

18. Salt replacement Salt enhancers • Compounds that do not have themselves a salty taste, but enhance a salty taste when used in combination with NaCl • Amino acids (glycine, lysine, taurine and aginine), glycine ester and lactates • Amino acids had no consistent enhancement effect in solution or in food • Glycine ester successfully compensated for salt taste in products with a 30% reduction in their salt content, although it had a sour note • Potasium lactate was the most effective salt enhancer in solution and in all of the foods tested • It compensated loss in saltiness in products with a reduced salt content of up to 30% without off-flavour • (Phelps et al. 2006)

19. Salt replacement Umami • Taste comes from glutamate • Naturally lot of in mushrooms, tomato and soy sauce • Monosodium glutamate (flavour enhancer) and 5’ribonukleotides (Ionosine monophosphate, IMP and guanosine monophosphate, GMP) can be used for forming umami taste or Monosodium glutamate and yeast extract • When added in suitable foods (meat fish, seafood, vegetable foods and mixed products of these raw materials) has considerable impact on their sensory and hedonic properties • Resulting increased richness, savouriness, saltiness and palatability Barylko-Pikielna and Kostyra (2007); Roininen et al. 1996; Yamaguchi, 1998

20. Salt replacement Umami • 0.3% and 0.5% amount of salt in lentil, mushroom, leak-potato and minestrone soups • Eight weeks of repeated testing • Low- and high-salt preference respondents • The pleasantness, taste intensity and ideal saltiness rating of soups were higher in soups with umami in both preference groups • Soups without umami pleasantness decreased during repeated testing while soups with umami it remained unchanged • Sodium was reduced 40% • (Roininen et al. 1996)

21. Salt replacement Salt at the top of the product • Crackers, mashed potato and an omelet was perceived saltier when the product was salted only from surface compared to the conventional way of salting (Mattes 1987) • Liver pate was perceived saltier when salted from the surface (Shepherd et al 1989) Physical modification of physical for of salt • Salt was prepared with small crystal sizes and blended with varying concentrations of potassium chloride • Smaller crystal size was associated with faster salt perception (Phelps et al. 2006)

22. Can salt be reduced without affecting the pleasantness • Yes, for certain limits • Mineral salts and umami • Maybe in the future bitterness of mineral salts can be better suppressed

23. Thank you for your attention! More information: katariina.roininen@vtt.fi