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The rationale for and challenges of reducing salt in foods
 

The rationale for and challenges of reducing salt in foods

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Dr. Ray Winger

Dr. Ray Winger

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    The rationale for and challenges of reducing salt in foods The rationale for and challenges of reducing salt in foods Presentation Transcript

    • A justificativa e os desafios da redução do sal nos alimentos.Dr Ray J Winger Dr Ray J WingerEmeritus Professor of Food Technology Managing DirectorMassey University Inside Foods LimitedNew Zealand United Kingdom Board member, Institute of Food Technologists, USA.
    • Outline Importance of salt to our health Sources of salt What is saltiness? Implications for product development Technological challenges for salt use Challenges and acheivements of reducing salt Pragmatic lowering of salt in food Example
    • The importance of salt to our health
    •  Humans need 10-20mmole sodium/day  230 – 460mg Na/day 1g Na = 2.5g salt  580 – 1160mg salt/day Evolutionary ancestors ate about 250mg salt/day Civilisation development  salt played a pivotal role  preservative – allowed communities to settle  highly prized, valued, taxed – a luxury
    •  Almost all Na ingested is absorbed into blood  active sodium pump
    •  Almost all Na ingested is absorbed into blood Regulates blood pressure and blood volume  blood volume 70kg man ~15litres  blood Na content ~50g  ~90% of the total body Na
    •  Almost all Na ingested is absorbed into blood Regulates blood pressure and blood volume Responsible for osmoregulation in our bodies  sodium-potassium-ATPase pump  uses a third of our bodies energy  high-Na & low-K extracellular, low-Na & high-K inside Involved in contraction and relaxation of muscles
    •  major studies:  INTERSALT (1985-1987)  52 populations  32 countries  INTERMAP (1996-1999)  17 populations  4 countries  Several individual countries  timeline of changes in salt consumption
    •  Lowest salt intake studied  Yanomamo Indians (Brazil)  0.8mmole Na/day for men (46mg salt/day)  1.0mmole Na/day for women (58mg salt/day)  Also low (<50mmole Na/day) (2.9g salt/day)  Xingu Indians (Brazil)  Papua New Guinea Highlanders  Luo (Kenya)INTERSALT Cooperative Group. (1988). BMJ 297:319-328Mancilha-Carvalho & de Souza e Silva (2003). Arq. Bras. Cardiol. 80 (3):295-300
    •  Highest salt consumption (INTERSALT)  Korea (385mmole Na/day) (22.3g salt/day)  Japan  Northern – 462mmole Na/day (26.8g salt/day)  Southern – 239mmole Na/day (13.9g salt/day)  People’s Republic of China - 259mmole Na/day  (15g salt/day)INTERSALT Cooperative Group. (1988). BMJ 297:319-328
    •  Overall modal value (INTERSALT)  150 – 199mmole Na/day for men (8.7-11.5g salt)  100 – 149mmole Na/day women (5.8 – 8.6g salt) Brazil has about 11g salt/day UK and USA about 9g salt/dayINTERSALT Cooperative Group. (1988). BMJ 297:319-328
    •  Need 10 – 20mmole Na/day  = 0.6 – 1.2g salt/day Range of consumptions  1mmole Na/day to 460mmole Na/day  = 0.06 – 26.7g salt/day  Most countries consume 100 – 199mmole Na/day  = 5.8 – 11.5g salt/day  men higher than women
    •  Huge day-to-day variability for an individual  >10-fold Best data are from 24-hour urine collections  only one sample  require >6 samples over prolonged period  Impractical  Records Na (not salt consumed)
    •  Blood pressure  Yanomami Indians: 95 / 61  Xingu: 99 / 62  Effective baseline target for no salt
    •  Salt and blood pressure  evidence is substantial  extremely controversial  about 33% population no influence at all  definite link to increasing bp with age (>60 years)  definite link to bp and renal insufficiency  unable to adequately excrete Na
    •  Salt and blood pressure Relationship to ischemic stroke  strong epidemiological evidence from Japan Strong relationship to cardiovascular mortality Critical for water retention  major cause of oedema in women  heart failure  left ventricular hypertrophy  increased stiffness of blood vessels
    •  Stomach cancer  possible links to Helicobacter pylori Urinary calcium excretion  kidney stones  bone mineral density
    • Typical target salt levels by governments
    •  USA 2010 guidelines  recommend no more than 2300mg Na/day  further reduce to 1500mg Na/day for people:  51 years and older  any age and  are Afro-American  have hypertension  have diabetes  have chronic kidney disease
    •  UK guidelines  10 years and older  1600mg Na/day Key issue for all public health professionals is:  sodium to potassium ratio  used to be about 1:7 (ancestors)  now 3:1
    •  Pan American Health Organisation / WHO  policy goal  target of <5g salt/person/day by 2020 20-33% of adults in Americas are hypertensive  above 80 years old this is >90% Want standard food labelling  educating children on health risks of excess salt
    •  USA market insight  45% of consumers check Na on food labels  70% used low Na foods/beverages in 2006  78% used them in 2007Source: NMI Health and Wellness Trends Database, 2007.
    • Where does salt come from in our diet?
    •  Cereals and cereal products  breakfast cereals  bread  pasta  pizza
    •  Cereals and cereal products Meat and meat products  bacon  ham  sausages  marinades  red meat and poultry (includes natural Na)  fish and seafood
    •  Cereals and cereal products Meat and meat products Prepared meals  restaurants  ready made meals  takeaway foods  Chinese and Indian foods  soups  sauces
    •  Cereals and cereal products Meat and meat products Prepared meals Dairy products Vegetable, tomato and fruit juices
    •  UK  focuses on specific food groups high in added salt  sets targets they believe are realistic  examples: food group current Na target Na level level mg/100g mg/100g pizza 600 300 cheese 700 500 bacon and ham 1491 750 burgers 503 300 sandwiches (bought) 500 350
    •  UK  focuses on specific food groups high in added salt  sets targets they believe are realistic Issue:  where salt has a key preservative role, may:  reduce safety margins in relevant foods  create unsafe food  reduce shelf life significantly (food spoilage)  increase incidence of food poisoning
    •  Kraft Foods Ltd reduced salt in 1000 products  by 10% over 2 years  saved 4500 tonnes salt / year  that’s the weight of 25 jumbo jets....
    •  ConAgra Foods Ltd, Nebraska  removed 2.8 million pounds from USA diet  (1,260 tonnes)  from entrees (prepared meals)
    • Salt usage Number (%) of consumers Never Occasionally Frequently AlwaysIn cooking 31 36 8 25At the table 20 43 15 21Purdy & Armstrong (2007). In: Reducing Salt in foods. Kilcast & Angus. Woodhead Publishing Ltd, UK.
    •  Generally over consume Na  Under consume potassium (K)  Under consume calcium (Ca)
    • What is saltiness?
    •  Salty taste is a response to regulating Na levels  no body stores of Na  need to respond to sudden Na-depletion quickly Only sodium and lithium taste salty  certain circumstances – potassium, calcium NaCl is most salty of all Na compounds
    •  Salt is perceived in taste buds on the tongue  unsure exactly how in humans  involves Na-ions through a narrow ion channel? Nerve impulses to brain  increases blood flow in specific parts of the brain Blood hormones influence Na  angiotensin II  aldosterone
    •  Salty taste is perceived on tongue Salt also modifies perceived flavours of food  perception is in the nose  not a direct effect of NaCl as this is not volatile  modifies volatility of aroma chemicals?
    •  Na-deprived animals have a compensatory appetite for salt NaCl pleasantness depends on other attributes  texture of food  some liquid foods (soup) better with excess NaCl
    •  Acute sodium loss (eg vomiting, diarrhoea)  show reduction in perceived intensity of salt  increase in pleasantness of salty foods
    •  Reduced sodium diets  after 8-12 weeks, preferred NaCl concentration is reduced  original higher level is unpleasant
    •  Clear evidence of foetal environment and salt preferences during later life Mothers with regular morning sickness  acute and sustained salt deficiency during pregnancy  off-spring have higher salt preference Higher salt consumption by mother  reflected in amniotic fluid  children consume higher salt  (close correlation to mother)
    • Implications for product development
    •  There are no effective sodium-free salt substitutes that mimic salt taste Salt is used to mask bitter tastes  are there alternative Na-free masks? Can we enhance salty taste  results in reduction of salt for same perception
    •  Gradual reduction in salt over prolonged time  salt taste can be changed  requires time  requires an industry-wide coordinated effort Never forget:  taste and flavour is the #1 consumer driver
    •  The medium the Na is presented has a profound impact on taste perception Up to about 30% salt reduction  single main salt carrier (eg beef in a stew)  salt perception significantly reduced  acceptability ratings not changed significantly  multiple salt carriers (eg vegetable soup)  salt perception relatively similar to original
    •  Complex food dishes  create a variety of tastes and flavours  30% salt reduction without affecting acceptability Coarse texture better for reducing salt than smooth texture
    • Technological functions of salt
    •  Preservative (5 – 20% salt)  meat  fish  pickled vegetables  mayonnaises and sauces As a component part of hurdle technology  3-6% salt plus other hurdles (chilling, acid, etc)
    • Salt concentration water activity % NaCl 1.7 0.99 3.4 0.98 6.6 0.96 9.4 0.94 11.9 0.92 14.2 0.90 16.3 0.88 18.2 0.86Most undesirable food bacteria stop growing around Aw = 0.92Yeasts and moulds are mainly controlled below Aw = 0.85Betts et al., 2007. In: Reducing salt in foods. Kilcast & Angus. Woodhead Publishing Ltd., UK.
    •  Preservative Control fermentation conditions  yeast and microbial growth  bread  cheese  fermented pickles  fermented sausages
    •  Preservative Control fermentation conditions Assist in product texture  bread  meat products  breakfast cereals  pickled vegetables  extruded snacks  cheese
    •  Preservative Control fermentation conditions Assist in product texture As a processing aid  bread (dough formation, structure)  sausages (emulsion development, stability)  cheese (physical structuring of protein)  baked goods (gelatinisation, gluten development)
    • Challenges in reducing salt (ie. how to do it)
    • Challenges and achievements in reducing salt The most common procedure in UK  slow, small, stepwise reduction in salt from product formulations over a long time  from 1998 to 2005 - 33% reduction in many foods  Heinz Foods Ltd (11-18% reduction)  Kraft reduced processed cheese salt by 33% Significant choice of no-added-salt foods  breakfast cereals  margarines, butter
    • Challenges and achievements in reducing salt Create more complex flavour mixtures  use of herbs and spices  increase in quantity of main components  use of specific ingredients to strengthen taste  lemon  onion, garlic  vinegar and other acids  chilli
    • Challenges and achievements in reducing salt Distinct from salt replacers (though fuzzy) Amino acids  glycine  L-lysine and L-arginine  hydrolysed protein savoury flavours yeast extracts  amino acid mixtures cultured products  often bitter  glutamates (especially MSG)  L-ornithine  dipeptides, tripeptides
    • Challenges and achievements in reducing salt Amino acids Nucleotides  5ʹ-ribonucleotides  disodium guanylate  disodium inosinate  inosine 5ʹ-monophosphate (IMP)  5ʹ-guanidyllic acid
    • Challenges and achievements in reducing salt Amino acids Nucleotides Lactates  sodium, potassium and calcium lactates Trehalose  Cargill - ASCEND™ Alapyridaine  (N-(1-carboxyethyl)-6-hydroxymethyl-pyridinium-3-ol)
    • Challenges and achievements in reducing salt potassium chloride  most common substitute  bitter / chemical / metallic taste and aftertaste  requires masking at high concentrations  feasible in some products to 30 – 50% substitution  enormous range of bitterness sensitivity among consumers  often combined with other salts  MSG  ammonium chloride, magnesium sulphate  amino acids
    • KClean™ saltNaCl and KCl with a proprietaryadditive to mask the bitterness NaCl , KCl Na-gluconate
    • Challenges and achievements in reducing salt potassium chloride calcium chloride  need high concentration to get salty taste  comes with bitter and sour tastes  irritation and metallic taste  works OK in conjunction with NaCl (masks bitterness)  sugar and citric acid also assist
    • Challenges and achievements in reducing salt potassium chloride calcium chloride Magnesium sulphate  also bitter  salty at low concentrations  often a significant component of ‘low Na’ sea salt
    • Challenges and achievements in reducing salt  potassium chloride  calcium chloride  magnesium sulphate  metal ions and sea salt  Oshima Blue (Japan)  Icelandic US$14 / 240g Rudolf Wild GmbH & Co. Ltd Germany Sea SaltTrim™: Low in sodium, great in taste contains sea salt with natural high40% Na content of salt concentration of non-NaCl minerals Na content ~ 45% normal salt
    • Challenges and achievements in reducing salt Salt crystal size important for perception of saltiness  normal table salt -- crystal size 200-500microns  microfine salt – crystal size 10-100microns  nanosalt – crystal size 0.005 – 0.01microns Smallest crystals give strongest saltiness perception Tate & Lyle signs exclusive worldwide agreement with University of Nottingham subsidiary for its novel salt reduction technology nanosalt
    • Challenges and achievements in reducing salt Salt crystal size important for perception of saltiness Emulsion technology  oil-in-water emulsion versus water-in-oil emulsion  when water is external continuous phase (oil-in-water)  much more salty than water-in-oil Emerging emulsions:  water-in-oil-in-water  small volume of external water phase could be very salty  major internal water phase no salt  saltiness perception from external water phase only  overall salt content can be significantly reduced in the food
    • Challenges and achievements in reducing salt Replacing sodium with potassium salts  use of potassium bicarbonate for baking  modification of polyphosphates KUDOS™ Potassium Bicarbonate BENEPHOSTM Sodium potassium hexametaphosphate to replace sodium metaphosphates
    • Challenges and achievements in reducing salt Use of dairy salts NatraSal Mineral Whey Concentrate
    • Challenges and achievements in reducing salt There are 25 G-protein coupled receptors for bitterness  also called TAS2R  shows importance of bitter taste to human survival  identifies potential toxic chemicals and poisons Totally different perception mechanism than salt salt and sugar decrease perception of bitter IMP and GMP increase impact of MSG on umami taste
    • Challenges and achievements in reducing salt Adenosine monophosphate (AMP) reduces KCl bitterness Givauden Flavors  GIV3616 – a new chemical blocker of bitterness Yeast hydrolysates Prime Favorites  NeutralFres®  blocks KCl bitterness
    • Pragmatic issues for lowering salt in foods and beverages
    •  Identify goals  who is your consumer?  why are you doing this?  introducing a new variant (no, or low salt)?  changing your existing products? What are your competitors doing?  are there products already there?  are they selling well?  what level of change are you envisaging?  can you differentiate from competitors (price, etc)?
    •  What are the sources of sodium in your product?  not all sodium is NaCl  animal foods all have high natural Na  some plants have higher levels than others  many food additives have sodium The only reliable ‘salt’ measurement in foods is Na What is your target Na reduction?
    •  Are you wishing to reduce Na in existing products?  or are you creating a new version? Consumer test your products  understand what happens as you change Na levels  what can be perceived  what affects acceptability (may not be salt!)
    •  Can you make a health claim?  low sodium  reduced sodium  very low sodium? What’s your marketing message?  clarity?  stealth?
    • An example
    •  Products designed for people with renal disease  require no added salt  for reducing hypertension  reducing fluid accumulation  reducing cardiovascular damage  cannot use salt replacers (K is deadly to these people) Complete meal to compensate for lethargy  lack of adequate kidney functionality  accumulate toxins in blood  tiredness associated with toxin accumulation
    •  Formulations:  no added salt  careful selection of ingredients  increased protein component  added herbs and spices Create multicomponent formulations Spice levels a bit higher than normal
    • Beef casserole 30Frequency of responses 25 20 15 Appearance 10 Aroma Flavour 5 0 1 2 3 4 5 6 7 Degree of liking 1= dislike extremely; 7 = like extremely 30 Thai chicken curry 25 Frequency of responses 20 15 Appearance 10 Aroma Flavour 5 0 1 2 3 4 5 6 7 Degree of liking