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Creedon AC, Hung ES, Dimidi E, Grassby T, Berry SE, Whelan K. Particle Size Distribution and Predicted Lipid Bioaccessibility of Almonds and the Effect of Almond Processing: A Randomised Mastication Study in Healthy Adults. Nutrients 2023; 15:nu15030489. [PMID: 36771196 PMCID: PMC9919979 DOI: 10.3390/nu15030489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
Almonds are rich in unsaturated lipids, which play a role in some of the reported benefits of almond consumption for human health. Almond lipids are poorly bioaccessible due to almonds' unique physicochemical properties that influence particle size distribution (PSD) following mastication, allowing much intracellular lipid to escape digestion in the upper gastrointestinal tract. To investigate the impact of commercial processing (grinding almonds into flour), on PSD and predicted lipid bioaccessibility following mastication, a randomised cross-over design mastication study was conducted in healthy adults. The PSDs of masticated whole and ground almonds was assessed using two laboratory methods (mechanical sieving and laser diffraction). PSD from mechanical sieving was used to calculate lipid bioaccessibility using a theoretical mathematical model. Thirty-one healthy adults (18-45 years) completed both mastication sessions. Following mastication, ground almonds had a PSD with significantly fewer larger particles and more smaller particles, compared with whole almonds. Predicted lipid bioaccessibility of masticated ground almonds (10.4%, SD 1.8) was marginally but significantly greater than the predicted lipid bioaccessibility of masticated whole almonds (9.3%, SD 2.0; p = 0.017). Commercial grinding of almonds significantly influences the PSD of almonds following mastication, which results in a modest but significant increase in predicted lipid bioaccessibility.
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Affiliation(s)
- Alice C. Creedon
- Department of Nutritional Sciences, King’s College London, London SE1 9NH, UK
| | - Estella S. Hung
- Department of Nutritional Sciences, King’s College London, London SE1 9NH, UK
| | - Eirini Dimidi
- Department of Nutritional Sciences, King’s College London, London SE1 9NH, UK
| | - Terri Grassby
- School of Biosciences, University of Surrey, Guildford GU2 7XH, UK
| | - Sarah E. Berry
- Department of Nutritional Sciences, King’s College London, London SE1 9NH, UK
| | - Kevin Whelan
- Department of Nutritional Sciences, King’s College London, London SE1 9NH, UK
- Correspondence:
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Creedon AC, Dimidi E, Hung ES, Rossi M, Probert C, Grassby T, Miguens-Blanco J, Marchesi JR, Scott SM, Berry SE, Whelan K. The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and mastication study. Am J Clin Nutr 2022; 116:1790-1804. [PMID: 36130222 PMCID: PMC9761756 DOI: 10.1093/ajcn/nqac265] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/16/2022] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Almonds contain lipid, fiber, and polyphenols and possess physicochemical properties that affect nutrient bioaccessibility, which are hypothesized to affect gut physiology and microbiota. OBJECTIVES To investigate the impact of whole almonds and ground almonds (almond flour) on fecal bifidobacteria (primary outcome), gut microbiota composition, and gut transit time. METHODS Healthy adults (n = 87) participated in a parallel, 3-arm randomized controlled trial. Participants received whole almonds (56 g/d), ground almonds (56 g/d), or an isocaloric control in place of habitual snacks for 4 wk. Gut microbiota composition and diversity (16S rRNA gene sequencing), SCFAs (GC), volatile organic compounds (GC-MS), gut transit time (wireless motility capsule), stool output and gut symptoms (7-d diary) were measured at baseline and endpoint. The impact of almond form on particle size distribution (PSD) and predicted lipid release was measured (n = 31). RESULTS Modified intention-to-treat analysis was performed on 79 participants. There were no significant differences in mean ± SD abundance of fecal bifidobacteria after consumption of whole almonds (8.7% ± 7.7%), ground almonds (7.8% ± 6.9%), or control (13.0% ± 10.2%; q = 0.613). Consumption of almonds (whole and ground pooled) resulted in higher mean ± SD butyrate (24.1 ± 15.0 μmol/g) than control (18.2 ± 9.1 μmol/g; P = 0.046). There was no effect of almonds on gut microbiota at the phylum level or diversity, gut transit time, stool consistency, or gut symptoms. Almond form (whole compared with ground) had no effect on study outcomes. Ground almonds resulted in significantly smaller PSD and higher mean ± SD predicted lipid release (10.4% ± 1.8%) than whole almonds (9.3% ± 2.0%; P = 0.017). CONCLUSIONS Almond consumption has limited impact on microbiota composition but increases butyrate in adults, suggesting positive alterations to microbiota functionality. Almonds can be incorporated into the diet to increase fiber consumption without gut symptoms.This trial was registered at clinicaltrials.gov as NCT03581812.
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Affiliation(s)
- Alice C Creedon
- Department of Nutritional Sciences, King's College London, London, United Kingdom
| | - Eirini Dimidi
- Department of Nutritional Sciences, King's College London, London, United Kingdom
| | | | - Megan Rossi
- Department of Nutritional Sciences, King's College London, London, United Kingdom
| | - Christopher Probert
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Terri Grassby
- Department of Nutritional Sciences, University of Surrey, Guildford, United Kingdom
| | | | - Julian R Marchesi
- Division of Digestive Diseases, Imperial College London, London, United Kingdom
| | - S Mark Scott
- Department of Neuroscience, Surgery and Trauma, Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Sarah E Berry
- Department of Nutritional Sciences, King's College London, London, United Kingdom
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Sadler CR, Grassby T, Hart K, Raats MM, Sokolović M, Timotijevic L. “Even We Are Confused”: A Thematic Analysis of Professionals' Perceptions of Processed Foods and Challenges for Communication. Front Nutr 2022; 9:826162. [PMID: 35284464 PMCID: PMC8904920 DOI: 10.3389/fnut.2022.826162] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/11/2022] [Indexed: 12/29/2022] Open
Abstract
Processed foods are increasingly under the spotlight since the development of classification systems based on proxies for food processing. Published critical reviews and commentaries suggest different views among professional disciplines about the definition and classification of processed food. There is a need to further understand perspectives of professionals on the conceptualisation of processed food and the agreements and disagreements among experts, to encourage interdisciplinary dialogue and aid communication to the public. The aim of this research was to elicit views and understandings of professionals on processed food, their perceptions of lay people's perceptions of the same, and their perspectives on the challenges of communicating about processed foods to the public. The online discussion groups brought together a range of professionals (n = 27), covering the fields of nutrition, food technology, policy making, industry, and civil society, mixed in 5 heterogenous groups. Through thematic analysis the following themes relating to the conceptualisation of processed food and challenges for communication were identified: (1) Broad concepts that need differentiation; (2) Disagreements on scope and degree of processing; (3) The role of food processing within the food system: the challenges in framing risks and benefits; and (4) The challenge of different perspectives and interests for risk communication. Throughout the discussions blurred lines in the characterisation of processing, processed foods, and unhealthy foods were observed. Participants agreed that consensus is important, but difficult. Participants identified a need for further interdisciplinary dialogue, including public engagement, to break down the observed issues, and work towards a mutual understanding and develop clear communication messages.
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Affiliation(s)
- Christina R. Sadler
- Department of Nutritional Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Food, Consumer Behaviour and Health Research Centre, School of Psychology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- European Food Information Council, Brussels, Belgium
- *Correspondence: Christina R. Sadler
| | - Terri Grassby
- Department of Nutritional Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Kathryn Hart
- Department of Nutritional Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Monique M. Raats
- Food, Consumer Behaviour and Health Research Centre, School of Psychology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | | | - Lada Timotijevic
- Food, Consumer Behaviour and Health Research Centre, School of Psychology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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Mandalari G, Parker ML, Grundy MML, Grassby T, Smeriglio A, Bisignano C, Raciti R, Trombetta D, Baer DJ, Wilde PJ. Understanding the Effect of Particle Size and Processing on Almond Lipid Bioaccessibility through Microstructural Analysis: From Mastication to Faecal Collection. Nutrients 2018; 10:nu10020213. [PMID: 29443942 PMCID: PMC5852789 DOI: 10.3390/nu10020213] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 02/06/2018] [Accepted: 02/09/2018] [Indexed: 11/30/2022] Open
Abstract
We have previously reported on the low lipid bioaccessibility from almond seeds during digestion in the upper gastrointestinal tract (GIT). In the present study, we quantified the lipid released during artificial mastication from four almond meals: natural raw almonds (NA), roasted almonds (RA), roasted diced almonds (DA) and almond butter from roasted almonds (AB). Lipid release after mastication (8.9% from NA, 11.8% from RA, 12.4% from DA and 6.2% from AB) was used to validate our theoretical mathematical model of lipid bioaccessibility. The total lipid potentially available for digestion in AB was 94.0%, which included the freely available lipid resulting from the initial sample processing and the further small amount of lipid released from the intact almond particles during mastication. Particle size distributions measured after mastication in NA, RA and DA showed most of the particles had a size of 1000 µm and above, whereas AB bolus mainly contained small particles (<850 µm). Microstructural analysis of faecal samples from volunteers consuming NA, RA, DA and AB confirmed that some lipid in NA, RA and DA remained encapsulated within the plant tissue throughout digestion, whereas almost complete digestion was observed in the AB sample. We conclude that the structure and particle size of the almond meals are the main factors in regulating lipid bioaccessibility in the gut.
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Affiliation(s)
- Giuseppina Mandalari
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy.
- Quadram Institute Bioscience, Norwich NR4 7UA, UK.
| | | | | | - Terri Grassby
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
| | - Antonella Smeriglio
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy.
| | - Carlo Bisignano
- Department of Biomedical, Dental, Morphological and Functional Images Sciences, University of Messina, Via C. Valeria, 98125 Messina, Italy.
| | - Roberto Raciti
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy.
| | - Domenico Trombetta
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy.
| | - David J Baer
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Centre, Building 307B, Room 213, BARC-East, Beltsville, MD 20705, USA.
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Grassby T, Mandalari G, Grundy MML, Edwards CH, Bisignano C, Trombetta D, Smeriglio A, Chessa S, Ray S, Sanderson J, Berry SE, Ellis PR, Waldron KW. In vitro and in vivo modeling of lipid bioaccessibility and digestion from almond muffins: The importance of the cell-wall barrier mechanism. J Funct Foods 2017; 37:263-271. [PMID: 29034005 PMCID: PMC5628021 DOI: 10.1016/j.jff.2017.07.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We investigated the mechanisms of lipid bioaccessibility from almond muffins. An in vitro dynamic gastric model was used to simulate human digestion. A pilot ileostomy study was performed to define the rate of lipid release. Microstructural analysis proved that some lipid remained encapsulated within matrix. The cell-wall is the main factor regulating the lipid bioaccessibility.
This study compares in vitro and in vivo models of lipid digestion from almond particles within a complex food matrix (muffins) investigating whether the cell-wall barrier regulates the bioaccessibility of nutrients within this matrix. Muffins containing small (AF) or large (AP) particles of almond were digested in triplicate using an in vitro dynamic gastric model (DGM, 1 h) followed by a static duodenal digestion (8 h). AF muffins had 97.1 ± 1.7% of their lipid digested, whereas AP muffins had 57.6 ± 1.1% digested. In vivo digestion of these muffins by an ileostomy volunteer (0–10 h) gave similar results with 96.5% and 56.5% lipid digested, respectively. The AF muffins produced a higher postprandial triacylglycerol iAUC response (by 61%) than the AP muffins. Microstructural analysis showed that some lipid remained encapsulated within the plant tissue throughout digestion. The cell-wall barrier mechanism is the main factor in regulating lipid bioaccessibility from almond particles.
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Affiliation(s)
- Terri Grassby
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Giuseppina Mandalari
- Quadram Institute Bioscience, Norwich NR4 7UA, UK.,Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy
| | - Myriam M-L Grundy
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Cathrina H Edwards
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Carlo Bisignano
- Department of Biomedical, Dental, Morphological and Functional Images Sciences, University of Messina, Via C. Valeria, 98125 Messina, Italy
| | - Domenico Trombetta
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy
| | - Antonella Smeriglio
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Viale SS. Annunziata, 98168 Messina, Italy
| | | | - Shuvra Ray
- Department of Gastroenterology, Guy's and St. Thomas' NHS Foundation Trust, London SE1 9RT, UK
| | - Jeremy Sanderson
- Department of Gastroenterology, Guy's and St. Thomas' NHS Foundation Trust, London SE1 9RT, UK
| | - Sarah E Berry
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Peter R Ellis
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
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Lovegrove A, Edwards CH, De Noni I, Patel H, El SN, Grassby T, Zielke C, Ulmius M, Nilsson L, Butterworth PJ, Ellis PR, Shewry PR. Role of polysaccharides in food, digestion, and health. Crit Rev Food Sci Nutr 2017; 57:237-253. [PMID: 25921546 PMCID: PMC5152545 DOI: 10.1080/10408398.2014.939263] [Citation(s) in RCA: 294] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/24/2014] [Accepted: 06/24/2014] [Indexed: 12/19/2022]
Abstract
Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets.
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Affiliation(s)
- A. Lovegrove
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, United Kingdom
| | - C. H. Edwards
- King's College London, Diabetes and Nutritional Sciences Division, School of Agriculture, Policy and Development, London, United Kingdom
| | - I. De Noni
- Department of Food, Environmental and Nutritional Sciences, University of Milan, Milan, Italy
| | - H. Patel
- King's College London, Diabetes and Nutritional Sciences Division, School of Agriculture, Policy and Development, London, United Kingdom
| | - S. N. El
- Food Engineering Department, Nutrition Section, Ege University, Izmir, Turkey
| | - T. Grassby
- King's College London, Diabetes and Nutritional Sciences Division, School of Agriculture, Policy and Development, London, United Kingdom
| | - C. Zielke
- Food Colloids Group, Department of Food Engineering, Technology and Nutrition, Faculty of Engineering LTH, Lund University, Lund, Sweden
| | - M. Ulmius
- Solve Research and Consultancy AB, Lund, Sweden
| | - L. Nilsson
- Food Colloids Group, Department of Food Engineering, Technology and Nutrition, Faculty of Engineering LTH, Lund University, Lund, Sweden
| | - P. J. Butterworth
- King's College London, Diabetes and Nutritional Sciences Division, School of Agriculture, Policy and Development, London, United Kingdom
| | - P. R Ellis
- King's College London, Diabetes and Nutritional Sciences Division, School of Agriculture, Policy and Development, London, United Kingdom
| | - P. R. Shewry
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, United Kingdom
- Department of Agriculture, Reading University, Whiteknights, Reading, Berkshire, United Kingdom
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Edwards CH, Grundy MM, Grassby T, Vasilopoulou D, Frost GS, Butterworth PJ, Berry SE, Sanderson J, Ellis PR. Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants. Am J Clin Nutr 2015; 102:791-800. [PMID: 26333512 PMCID: PMC4588739 DOI: 10.3945/ajcn.114.106203] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 07/31/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Cereal crops, particularly wheat, are a major dietary source of starch, and the bioaccessibility of starch has implications for postprandial glycemia. The structure and properties of plant foods have been identified as critical factors in influencing nutrient bioaccessibility; however, the physical and biochemical disassembly of cereal food during digestion has not been widely studied. OBJECTIVES The aims of this study were to compare the effects of 2 porridge meals prepared from wheat endosperm with different degrees of starch bioaccessibility on postprandial metabolism (e.g., glycemia) and to gain insight into the structural and biochemical breakdown of the test meals during gastroileal transit. DESIGN A randomized crossover trial in 9 healthy ileostomy participants was designed to compare the effects of 55 g starch, provided as coarse (2-mm particles) or smooth (<0.2-mm particles) wheat porridge, on postprandial changes in blood glucose, insulin, C-peptide, lipids, and gut hormones and on the resistant starch (RS) content of ileal effluent. Undigested food in the ileal output was examined microscopically to identify cell walls and encapsulated starch. RESULTS Blood glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide concentrations were significantly lower (i.e., 33%, 43%, 40%, and 50% lower 120-min incremental AUC, respectively) after consumption of the coarse porridge than after the smooth porridge (P < 0.01). In vitro, starch digestion was slower in the coarse porridge than in the smooth porridge (33% less starch digested at 90 min, P < 0.05, paired t test). In vivo, the structural integrity of coarse particles (∼2 mm) of wheat endosperm was retained during gastroileal transit. Microscopic examination revealed a progressive loss of starch from the periphery toward the particle core. The structure of the test meal had no effect on the amount or pattern of RS output. CONCLUSION The structural integrity of wheat endosperm is largely retained during gastroileal digestion and has a primary role in influencing the rate of starch amylolysis and, consequently, postprandial metabolism. This trial was registered at isrctn.org as ISRCTN40517475.
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Affiliation(s)
- Cathrina H Edwards
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Myriam Ml Grundy
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Terri Grassby
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Dafni Vasilopoulou
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Gary S Frost
- Nutrition and Dietetic Research Group, Faculty of Medicine, Hammersmith Campus, Imperial College, London, United Kingdom
| | - Peter J Butterworth
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Sarah Ee Berry
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Jeremy Sanderson
- Department of Gastroenterology, Guy's and St. Thomas' National Health Service Foundation Trust, London, United Kingdom; and
| | - Peter R Ellis
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom;
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Grassby T, Picout DR, Mandalari G, Faulks RM, Kendall CWC, Rich GT, Wickham MSJ, Lapsley K, Ellis PR. Modelling of nutrient bioaccessibility in almond seeds based on the fracture properties of their cell walls. Food Funct 2015; 5:3096-106. [PMID: 25310222 DOI: 10.1039/c4fo00659c] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cell walls (dietary fibre) of edible plants, which consist of mainly non-starch polysaccharides, play an important role in regulating nutrient bioaccessibility (release) during digestion in the upper gastrointestinal tract. Recent studies have shown that structurally-intact cell walls hinder lipid release from the parenchyma cells of almond seeds. A theoretical model was developed to predict the bioaccessibility of lipid using simple geometry and data on cell dimensions and particle size for calculating the number of ruptured cells in cut almond cubes. Cubes (2 mm) and finely-ground flour of low and high lipid bioaccessibility, respectively, were prepared from almond cotyledons. The model predictions were compared with data from in vitro gastric and duodenal digestion of almond cubes and flour. The model showed that lipid bioaccessibility is highly dependent on particle size and cell diameter. Only a modified version of the model (the Extended Theoretical Model, ETM), in which the cells at the edges and corners were counted once only, was acceptable for the full range of particle sizes. Lipid release values predicted from the ETM were 5.7% for almond cubes and 42% for almond flour. In vitro digestion of cubes and flour showed that lipid released from ruptured cells was available for hydrolysis and resulted in lipid losses of 9.9 and 39.3%, respectively. The ETM shows considerable potential for predicting lipid release in the upper gastrointestinal tract. Further work is warranted to evaluate the efficacy of this model to accurately predict nutrient bioaccessibility in a broad range of edible plants.
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Affiliation(s)
- Terri Grassby
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
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Grundy MML, Grassby T, Mandalari G, Waldron KW, Butterworth PJ, Berry SEE, Ellis PR. Effect of mastication on lipid bioaccessibility of almonds in a randomized human study and its implications for digestion kinetics, metabolizable energy, and postprandial lipemia. Am J Clin Nutr 2015; 101:25-33. [PMID: 25527747 PMCID: PMC4266890 DOI: 10.3945/ajcn.114.088328] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 10/07/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The particle size and structure of masticated almonds have a significant impact on nutrient release (bioaccessibility) and digestion kinetics. OBJECTIVES The goals of this study were to quantify the effects of mastication on the bioaccessibility of intracellular lipid of almond tissue and examine microstructural characteristics of masticated almonds. DESIGN In a randomized, subject-blind, crossover trial, 17 healthy subjects chewed natural almonds (NAs) or roasted almonds (RAs) in 4 separate mastication sessions. Particle size distributions (PSDs) of the expectorated boluses were measured by using mechanical sieving and laser diffraction (primary outcome). The microstructure of masticated almonds, including the structural integrity of the cell walls (i.e., dietary fiber), was examined with microscopy. Lipid bioaccessibility was predicted by using a theoretical model, based on almond particle size and cell dimensions, and then compared with empirically derived release data. RESULTS Intersubject variations (n = 15; 2 subjects withdrew) in PSDs of both NA and RA samples were small (e.g., laser diffraction; CV: 12% and 9%, respectively). Significant differences in PSDs were found between these 2 almond forms (P < 0.05). A small proportion of lipid was released from ruptured cells on fractured surfaces of masticated particles, as predicted by using the mathematical model (8.5% and 11.3% for NAs and RAs, respectively). This low percentage of lipid bioaccessibility is attributable to the high proportion (35-40%) of large particles (>500 μm) in masticated almonds. Microstructural examination of the almonds indicated that most intracellular lipid remained undisturbed in intact cells after mastication. No adverse events were recorded. CONCLUSIONS Following mastication, most of the almond cells remained intact with lipid encapsulated by cell walls. Thus, most of the lipid in masticated almonds is not immediately bioaccessible and remains unavailable for early stages of digestion. The lipid encapsulation mechanism provides a convincing explanation for why almonds have a low metabolizable energy content and an attenuated impact on postprandial lipemia.
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Affiliation(s)
- Myriam M L Grundy
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Terri Grassby
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Giuseppina Mandalari
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Keith W Waldron
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Peter J Butterworth
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Sarah E E Berry
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Peter R Ellis
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
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Grassby T, Jay AJ, Merali Z, Parker ML, Parr AJ, Faulds CB, Waldron KW. Compositional analysis of Chinese water chestnut (Eleocharis dulcis) cell-wall material from parenchyma, epidermis, and subepidermal tissues. J Agric Food Chem 2013; 61:9680-9688. [PMID: 24066627 DOI: 10.1021/jf401863n] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Chinese water chestnut (Eleocharis dulcis (Burman f.) Trin ex Henschel) is a corm consumed globally in Oriental-style cuisine. The corm consists of three main tissues, the epidermis, subepidermis, and parenchyma; the cell walls of which were analyzed for sugar, phenolic, and lignin content. Sugar content, measured by gas chromatography, was higher in the parenchyma cell walls (931 μg/mg) than in the subepidermis (775 μg/mg) or epidermis (685 μg/mg). The alkali-extractable phenolic content, measured by high-performance liquid chromatography, was greater in the epidermal (32.4 μg/mg) and subepidermal cell walls (21.7 μg/mg) than in the cell walls of the parenchyma (12.3 μg/mg). The proportion of diferulic acids was higher in the parenchyma. The Klason lignin content of epidermal and subepidermal cell walls was ~15%. Methylation analysis of Chinese water chestnut cell-wall polysaccharides identified xyloglucan as the predominant hemicellulose in the parenchyma for the first time, and also a significant pectin component, similar to other nongraminaceous monocots.
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Affiliation(s)
- Terri Grassby
- Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom
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Ellis PR, Grundy M, Grassby T, Mandalari G, Faulks RM, Berry SE, Waldron KW, Butterworth PJ. The role of dietary fiber in regulating lipid bioaccessibility of almonds during mastication. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1015.4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Peter R Ellis
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Myriam Grundy
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Terri Grassby
- School of MedicineKing's College LondonLondonUnited Kingdom
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Butterworth PJ, Warren FJ, Edwards CH, Grassby T, Patel H, Ellis PR. How analysis of data from alpha‐amylase catalysed starch digestibility performed
in vitro
contributes to an understanding of rates and extent of digestion starchy foods
in vivo. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.638.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Terri Grassby
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Hamung Patel
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Peter R. Ellis
- School of MedicineKing's College LondonLondonUnited Kingdom
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Knudsen GM, Nielsen MB, Grassby T, Danino-Appleton V, Thomsen LE, Colquhoun IJ, Brocklehurst TF, Olsen JE, Hinton JCD. A third mode of surface-associated growth: immobilization of Salmonella enterica serovar Typhimurium modulates the RpoS-directed transcriptional programme. Environ Microbiol 2012; 14:1855-75. [PMID: 22356617 DOI: 10.1111/j.1462-2920.2012.02703.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although the growth of bacteria has been studied for more than a century, it is only in recent decades that surface-associated growth has received attention. In addition to the well-characterized biofilm and swarming lifestyles, bacteria can also develop as micro-colonies supported by structured environments in both food products and the GI tract. This immobilized mode of growth has not been widely studied. To develop our understanding of the effects of immobilization upon a food-borne bacterial pathogen, we used the IFR Gel Cassette model. The transcriptional programme and metabolomic profile of Salmonella enterica serovar Typhimurium ST4/74 were compared during planktonic and immobilized growth, and a number of immobilization-specific characteristics were identified. Immobilized S.Typhimurium did not express motility and chemotaxis genes, and electron microscopy revealed the absence of flagella. The expression of RpoS-dependent genes and the level of RpoS protein were increased in immobilized bacteria, compared with planktonic growth. Immobilized growth prevented the induction of SPI1, SPI4 and SPI5 gene expression, likely mediated by the FliZ transcriptional regulator. Using an epithelial cell-based assay, we showed that immobilized S.Typhimurium was significantly less invasive than planktonic bacteria, and we suggest that S.Typhimurium grown in immobilized environments are less virulent than planktonic bacteria. Our findings identify immobilization as a third type of surface-associated growth that is distinct from the biofilm and swarming lifestyles of Salmonella.
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Affiliation(s)
- Gitte M Knudsen
- Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA, UK
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