EARLY FINDINGS FROM THE MOUTH-GUT-BRAIN PROJECT & RESEARCH INTO GUSTATORY RESPONSES TO FAT

Transcription

1 Sensory Science Centre Department of Food and Nutritional Sciences EARLY FINDINGS FROM THE MOUTH-GUT-BRAIN PROJECT & RESEARCH INTO GUSTATORY RESPONSES TO FAT Dr Lisa Methven 1 Copyright University of Reading

2 Fat Perception & Preference Hedon ic respon se (liking) Sensory Modalities Food selectio n and intake Mouthfeel Odour Taste Five basic taste: sweet, sour, salty, bitter, umami Fat as sixth taste ( oleogustus ) Fatty acid as stimuli Receptors (CD36 & G protein coupled receptors Transduction pathways (DRK, TRPM5)

3 Individual Variation in Fat Perception Saliva flow 3 CD36 Genotypes 5,6 At threshold level Above threshold level Fatty acid sensitivity 1,2 Oral perceived fat intensity 1,2,3 Salivary lipase activity 4,5 Expression of receptors 1 Stewart et al. (2010). Br J Nutr, 104(1), Stewart, Newman, & Keast. (2011). Clin Nutr, 30(6), Keller et al (2012). Obesity, 20(5), Mounayar, et al. (2013). Chem Percep, 6, Voigt, et al. (2014). J Lip Res, 55, Melis et al, (2015). Nutrients, 7(3), Mrizak et al, (2015). Br J Nutr, 1-8. Food intake and preference CD36 Genotypes 3

4 Aims of our previous study: To Understand. The relative effects of taste, mouthfeel and odour on fat perception in a real food model The relationship between fat perception in a real food model, fatty acid sensitivity, fat intake, fat liking The effects of CD36 genotypes and salivary lipase activity on individual fat perception and consumption

5 Many Methods! CD36 genotyping rs , rs , rs Buccal swabs collection Fat intensity rating Single cream and double cream added into skimmed milk 0%, 2.5%, 5%, 7.5%, 10%, 15%, 20% fat levels Salivary lipase activity Free oleic acid analysis from expectorated almond samples one almond per person, 1 bite/s for 15 seconds 85 participants Rating under taste condition Mouthfeel masked samples (containing thickener and liquid paraffin; nose-clip provided) Rating under overall condition Mouthfeel nonmasked samples Food liking Food Preference questionnaire 6 Dietary intake Food Frequency questionnaire Eating behaviour Three Factor Eating questionnaire Fat sensitivity Modified 3-AFC staircase method Skimmed milk emulsions with added oleic acid (ranged from 0.098mM to 55.9mM, 0.25 logunit dilutions

6 Method: Fatty acid TASTE Thresholds Skimmed milk emulsions with added oleic acid Oleic acid range: 0.098mM (0.0028%w/v) to 55.9mM (1.58%w/v) 0.25 log-unit dilutions Plus Thickener, Liquid Paraffin &EDTA 3-AFC staircase method Three samples were presented each time Start at the second lowest concentration Oleic acid concentration mm %w/v % % % Fat sensitivity (Detection threshold) Second reversal Question: Which sample is different from the other two? % % % % % % First reversal Third reversal Stop after a minimum four reversals % % %

7 Method: Fat intensity and 2AFC discrimination test Fat intensity rating Varied amount of single cream and double cream added into milk Fat intensity ratings under taste condition Mouthfeel masked samples 0%, 2.5%, 5%, 7.5%, 10%, 15%, 20% fat levels Thickener and liquid paraffin to minimize the viscosity and lubricity Nose-clip provided Fat intensity ratings under overall condition Mouthfeel non-masked samples 0%, 2.5%, 5%, 7.5%, 10%, 15%, 20% fat levels 2AFC discrimination test Fat levels: 0%, 2.5%, 5%, 7.5%, 10% Two samples were presented each time: which one is fattier

8 Method: Preference and Intake of Fatty Foods Food liking Food Preference Questionnaire (modified from the PrefQuest questionnaire 1 ) 9 point liking scale Preferred level of seasoning or fat related component Full fat milk Dislike Dislike very extremely much Dislike moderately Dislike slightly I don t eat it / I have never tasted it before Neither like nor dislike Like slightly Like moderately Like very much Like extremely How do you like your strawberry? Food intake EPIC-Norfolk Food frequency questionnaire (FFQ) Eating behaviours 51-food items Three factor eating questionnaire Without cream With lots of 7 cream I prefer much more cream than Image6 shows 8 If you don t like strawberry with cream but like strawberry with other things, please specify 9 I don t like strawberry 1 Deglaire et al. (2012). Food Qual Prefer, 23,

9 Fatty acid sensitivity Results: Fatty acid TASTE Thresholds Previous Studies: In the US (Chalé-Rush et al, ): mean detection threshold was 0.77mM (0.022%), ranged from 0.01 to 175mM ( % to 5%) In Australia (Stewart et al, 2010): mean detection threshold was 2.2mM, ranged from mM Classifying in Sensitivity Groups: Triplicate triangle test to classify participants into hyper-/hypo-sensitive groups 1.4mM as a cut-off point: 48% of subjects (n=31) in their pilot study could detect this level or lower levels 22% of subject in their later study (n=54): hyper-sensitive 78% of subject in their later study (n=54): hypo-sensitive 1 Chalé-Rush, Burgess, Mattes (2012). Chemical Senses, 32(5), Stewart et al (2010). B J Nutrition, 104(1),

10 Fatty acid sensitivity Our Results: Fatty acid TASTE Thresholds 0.55mM: 49% of subjects (n=43/87) could detect this level or lower levels Mean Detection Threshold: 0.22% (7.6mM); Median: % (0.55mM) 10

11 Perceived fat intensity Results : Discrimination of Fat Levels in a Dairy Model Fat levels were discriminated when mouthfeel & odour masked (Zhou et al, 2016) Fat level can be distinguished by taste Confirmed by 2AFC test * * * 0% 2.5% 5% 7.5% 10% 15% 20% Fat level * * Strong Moderate Weak Barely detectable No sensation p< Taste (from MM samples with NC) Overall (from MNM samples without NC) Zhou et al, (2016). Chem Percept 9:105-11

12 Results : Fatty acid TASTE Thresholds and Oral Fat Perception in a Dairy Model Subjects with high sensitivity to fatty acid could distinguish more pairs of fat levels in the dairy model Perceived fat intensity under Taste modality (left) and under Overall modality (right) for three sensitivity groups. Bars not sharing a common letter differ significantly (p<0.05) between fat levels within one sensitivity group 12

13 In Summary, we found: Fat can be perceived through taste modality Fat liking affects fat intake and is influenced by oral fat perception Both salivary lipase and CD36 genotype influenced oral fat perception The influence of CD36 genotypes on oral fat perception varied between subjects according to high or low salivary lipase activity; but this needs confirming in a larger cohort.

14 The Mouth Gut Brain (MGB) model: an integrated multidisciplinary approach to reduce risks of reformulation

15 Long Term Vision: To maximise repeat use of healthier foods, focussed on risks and challenges from nutrient reduction.

16 Mouth Gut Brain Model Big Picture A Liking Expectations Post ingestive effects E F C B D Schematic of the Mouth-Gut-Brain Model: A (Mouth to Brain, hedonic): tasting food leads to hedonic response in brain in addition to an expectation of satiety B (Mouth to Brain, expected satiety) C (Mouth to Gut): consuming the food leads to uptake of nutrients; taste receptors are located throughout the GI tract where they act as metabolite receptors. D (Gut to Brain): release of satiety hormones post-ingestion signaling post-ingestive satiety in the brain E (Brain post-ingestive to Brain expectation and hedonic signals): post ingestive satiety may match or mismatch sensory expected satiety (B) and influence expected hedonics and likelihood to consume on repeated exposure (F)

17 Complexity of fat reduction Sensory signalling Sensory perception of fat is multifaceted Mouth feel (texture) Oral fat receptors Related odour release Individual differences in fat sensitivity Mouth feel Oral fatty acid perception Post-ingestive signalling Reducing total fat reduces nutrient delivery and removes specific fatty acid cues How much reduction can be tolerated before functionality is lost? How can specific modifications (structuring, fatty acid profile) counter this?

18 In Summary: The MGB Project Milestone Months Action & Outcomes 1a 1-3 Establish Sensory Tolerance in Expected Satiety (mouthfeel matched emulsion model) (Hypo-sensitive subjects*) 1b 4-6 Establish Mouth Gut Discordance (Preload Satiety Test) (n=40) Design Fat Snack Model (min 25% reduction) Axes: Content / FA Profile & FFA content / Structure Release : In Mouth & In Vitro (Gut) In Vivo Testing (n=80; Hyper& Hypo Sensitive) Measures: Hedonic, Perception, Ex-Vivo (spit!) Physical & Chemical Genotype saliva, Expected Satiety Snack Refining Preload Satiety Study (n=80; Hyper & Hypo sensitive) 6 18 Dissemination & Confirmation of Main Study Design * Oral Fatty Acid sensitivity (Mouthfeel sensitivity will be measured but not used to categorise)

19 Volunteer characterisation Buccal swab collection Fatty acid sensitivity Biscuit tasting (mouthfeel sensitivity) Tongue photo Tactile sensitivity Mouth behaviour, Eating behavior, anthropometric collection 19

20 Fatty acid sensitivity Free oleic acid (0.55mM, %w/v, g in 100ml) Water Milk Thickener Liquid paraffin EDTA Oleic acid Control 80ml 20ml 1g 3g 0.01g n/a Sample 80ml 20ml 1g 3g 0.01g g The composition of 100ml sample used in fatty acid sensitivity Triplicate triangle test Each set contains two controls and one sample Hyper-sensitive: who could identify fatty acid samples three times over of the three sets Hyposensitive: less than three times over of the three sets 20

21 Tactile test Von Frey filament with 0.02g force Test is conducted ten times Five times with filament touch Five times with nothing R-index: probability of discriminating samples R-index value of 1.0: easily distinguishable R-index value of 0.5: extremely difficult to discriminate. Y-sure Y-unsure N-sure N-unsure Total R-index True a b c d 5 False e f g h 5 R index = a f+g+h +b g+h +c h+ 1 2 a e+b f+c g+d h /(5 5) 21

22 Mouth behaviour Our participants showed different mouth behaviours based on the mouth behaviour questionnaire (developed by Jeltema et al 2014) Individuals classified in each group (%) based on the study of Jeltema et al 2014 (n=500) Chewer 43% Cruncher 33% Smoosher 16% Sucker 8% 22

23 So, by next year. We hope to complete recruitment (!) Aim to determine extent of fat reduction to maintain expected satiety Aim to determine extent of discordance between expected satiety & post-ingestive satiety. 23

24 Thank Acknowledgements you. Dr Xirui Zhou All our participants All our project students Prof Pete Wilde (Quadram) Prof Martin Yeomans (Sussex) Dr Jane Parker & Prof Orla Kennedy Our Industrial Partners 24