Abstract
Functional food concept is one of the hot topics in the food industry. In recent years, people want to consume food products having health beneficial effect as well as nutritive characteristics. Regarding functional food development, foods have also advantages and disadvantages in terms of delivering bioactive compounds due to formulation (interaction of the bioactive compound with other ingredients, calorie value provided) and production process (mechanical and thermal processes applied during production). When considering the factors restricting usage of the food products as a delivery system, chewing gum is one of the most up-and-coming products in many aspects: (i) simplicity of the formulation prevents the activity of bioactive compound by interaction, (ii) level of mechanical and thermal stresses applied during production, (iii) enabling the release of targeted molecule in a controlled and sustained manner, (iv) different consumption behavior abolishing calorie intake concern since it is only chewed without swallowing, and (v) holding time in mouth. Usage of encapsulated bioactive compounds can improve the release behavior of the functional ingredient. Mastication process and the formed matrix/structure of the chewing gum also influence the release of the bioactive compounds. The researches about improving functionality of chewing gum have indicated that chewing gum can be used as a delivery system for transportation of the desired bioactive compound to body/targeted site. However, during functional chewing gum development, formulation, production process, mastication process, and type/form of bioactive compounds should be considered to achieve the product with required functional properties.
Abbreviations
- CMG:
-
Chios mastic gum
- EC:
-
Epicatechin
- ECG:
-
Epicatechin gallate
- EGC:
-
Epigallocatechin
- EGCG:
-
Epigallocatechin gallate
- FDA:
-
Food and Drug Administration
- FM:
-
Fusion method
- HPMC:
-
Hydroxypropyl methylcellulose
- MCG:
-
Medicated chewing gum
- MCGs:
-
Membrane coating granules
- MS:
-
Mutans streptococci
- NRT:
-
Nicotine replacement therapy
- ODF:
-
Oral disintegrating film
- PVAc:
-
Polyvinyl acetates
- Qt:
-
Quercetin
- TP:
-
Tea polyphenols
- UGTs:
-
UDP-glucuronosyltransferases enzymes
References
EPHAC (2010) Towards a healthier, more sustainable CAP (The European Agriculture and Public Health Consortiums position paper). http://eurohealthnet.eu/sites/eurohealthnet.eu/files/publications/EPHAC-Position
Granato D, Nunes DS, Barba FJ (2017) An integrated strategy between food chemistry, biology, nutrition, pharmacology, and statics in the development of functional foods: a proposal. Trends Food Sci Technol 62:13–22
Mark-Herbert C (2004) Innovation of a new product category-functional foods. Technovation 24:713–719
Menrad K (2003) Market and marketing of functional food in Europe. J Food Eng 56:181–188
Simões LDS, Madalena DA, Pinheiro AC, Teixeira JA, Vicente AA, Ramos LÓ (2017) Micro- and nano bio-based delivery systems for food applications: In vitro behavior. Adv Colloid Interf Sci 243:23–45
Hooper L, Cassidy A (2006) A review of the health care potential of bioactive compounds. J Sci Food Agric 86:1805–1813
Halliwell B (1995) How to characterize an antioxidant: an update. Biochem Soc Symp 61:73–101
Santos MG, Carpinteiro DA, Thomazini M, Rocha-Selmi GA, da Cruz AG, Rodrigues CEC, Favaro-Trindade CS (2014) Coencapsulation of xylitol and menthol by double emulsion followed by complex coacervation and microcapsule application in chewin gum. Food Res Int 66:454–462
Abbasi S, Rahimi S, Azizi MH (2009) Influence of microwave-microencapsulated citric acid on some sensory properties of chewing gum. J Microencapsul 26:90–96
Yang X, Wang G, Zhangi X (2004) Release kinetics of catechins from chewing gum. J Pharm Sci 93:293–299
Valduga E, Lazzari MR, Xardanega R, Di Luccio M (2012) Evaluation of sugar inversion in chewing gum added of sodium lactate. J Food Process Eng 35:37–53
Potineni RV, Peterson DG (2008) Influence of flavor solvent on flavor release and perception in sugar-free chewing gum. J Agric Food Chem 56:3254–3259
Fritz D (2008) Formulation and production of chewing gum and bubble gum. Kennedy’s Books Ltd, Essex
Konar N, Palabiyik I, Toker OS, Sagdic O (2016) Chewing gum: production, quality parameters and opportunities for delivering bioactive compounds. Trends Food Sci Technol 55:29–38
Potineni RV, Peterson DG (2008) Mechanisms of flavor release in chewing gum: Cinnamaldehyde. J Agricultural Food Chem 56:3260–3267
Cherukuri RS, Marschall-helman E, Hriscisce FT (1985) Non-adhesive chewing gum base composition. New York, Warner-Lambert Company
Pratik S, Asif K, Ramana MV, Mitul P, Mahesh K (2011) Chewing gum: a modern era of drug delivery. Int Res J Pharm 2:7–12
Gadhavi AG, Patel BN, Patel DM, Patel CN (2011) Medicated chewing gum a 21st century drug delivery system. Int J Pharm Sci Res 2:1961–1974
Ingole B, Daga AS, Joshi UM, Biyani KR (2012) Chewing gum: a mobile drug delivery system. Int J Pharm Sci Rev Res 14:106–114
Niederer B, Le A, Cantergiani E (2003) Thermodynamic study of two different chewing-gum bases by inverse gas chromatography. J Chromatogr A 996:189–194
Aslani A, Ghannadi A, Raddanipour R (2015) Design, formulation and evaluation of aloe vera chewing gum. Adv Biomed Res 4:175
Sameja K, Raval V, Asodiya H, Patadiya D (2011) Chewing gum: a modern approach to oral mucosal drug delivery. Int J Pharm Res Dev 4:001–016
Rose K, Steinbüchel A (2005) Biodegradation of natural rubber and related compounds: recent insights into a hardly understood catabolic capability of microorganisms. App Environ Microbiol 71:2803–2812
Farber TM, Clewell AE, Endres JR, Hauswirth J (2010) Safety assesment of a novel ingredient for removable chewing gum. Food Chem Toxico l48:831–838
Cook RB (1996) Confections comprising a proteinaceous chewable base. US patent 5,482,722
Mcgowan BA, Padua GW, Lee S-Y (2005) Formulation of corn zein chewing gum and evaluation of sensory properties by the time-intensity method. J Food Sci 70:475–481
Mehta FF, Triverdi P (2015) Formulation and characterization of Biodegredable medicated chewing gum delivery system for motion sickness using corn Zein as gum former. Trop J Pharm Res 14(5):753–760
Mehta F, Rajagopalan R, Trivedi P (2013) Formulation and texture characterization of environment friendly chewing gum. Int J of Pharm Tech Res 5(1):222–232
Palabiyik I, Toker OS, Konar N, Öner B, Demirci AS (2017) Development of a natural chewing gum from plant based polymer. J Polym Environ. https://doi.org/10.1007/s10924-017-1094-2
Nagasamy VD, Toprani PS, Mukherejee S, Tulasi K (2014) Medicated chewing gums – a review. Int. J Pharm Sci 4:581–586
Asija R, Patel S, Asija S (2012) Oral dosages forms: medicine containing chewing gum: a review. J Drug Deliv Ther 2:90–95
Smith AP, Woods M (2012) Effects of chewing gum on the stress and work of university students. Appetite 58:1037–1040
Nabors LO (2001) Alternatives sweeteners. Marcel Dekker, New York
Lakkis JM (2016) Encapsulation and controlled release technologies in food systems. Wiley Blackwell, UK
Bahoshy BJ, Klose RE, Nordstrom HA (1976) Chewing gums of longer lasting sweetness and flavor. General Foods Corp US 3:943,258
Bunczek MT, Urensis P (1993) Aspartame stability in chewing gum using an acid gelatin system. US Patent 5,192,561
Sharma SC, Yang KY (1986) Chewing gum compositions containing novel sweetener delivery systems and method of preparation. US Patent 4,597,970
Haahr AM, Pilsgaard CF, Stahnke LH, Bredie WLP, Refsgaard HHF (2003) Effect of sweetener on release of flavor compounds from chewing gum. In: Le Quere JL, Etievant PX (eds) Flavor research at the Dawn of the twenty-first century, proceedings of the 10th Weurman flavor research symposium. Intercept LLC, Paris
Tanzer JM, Freedman ML, Fitzgerald RJ (1984) Virulence of mutants defective in glucosyltransferase, dextranmediated aggregation, or dextran activity. In: Magenhagen S, Rosan B (eds) Molecular basis of oral microbial adhesion. American Society for Microbiology, Washington
Edwardson S, Birkhed D, Majare B (1977) Acid production from lycasin, maltitol, sorbitol and xylitol by oral streptococci and lactobacilli. Acta Odontol Scand 35:257–263
Thaweboon S, Thaweboon B, Soo-Ampon S (2004) The effect of xylitol chewing gum on mutans streptococci in saliva and dental plaque. Southeast Asian J Trop Med Public Health 35:1024–1027
Kleber CJ, Milleman JL, Putt MS, Nelson BJ, Proskin HM (1998) Clinical effects of baking soda chewing gum on plaque and gingivitis. J Dent Res 77:A290
Çaglar E, Kavaloglu SC, Kuscu OO, Sandalli N, Holgerson PL, Twetman S (2007) Effect of chewing gums containing xylitol or probiotic bacteria on salivary mutans streptococci and lactobacilli. Clin Oral Invest 11:425–429
Aslani A, Rostami F (2015) Medicated chewing gum, a novel drug delivery system. J Res Med Sci 20:403–411
Surana AS (2010) Chewing gum: a friendly oral mucosal drug delivery system. Int J Pharm Sci Rev Res 4:68–71
Semwal R, Semwal DK, Badoni R (2010) Chewing gum: a novel approach for drug delivery. J Appl Res 10:115–123
Rassing MR (1994) Chewing gum as a drug delivery system. Adv Drug Deliv Rev 13:89–121
Imfeld T (2006) Chlorhexidine-containing chewing gum. Schweiz Monatsschrz 116:476–483
Bijella MFTB, Brighenti FL, Bijella MFB, Buzalaf MAR (2005) Fluoride kinetics in saliva after the use of a fluoride containing chewing gum. Braz Oral Res 19:25–260
Aslani L, Ghannadi A, Mortazavi S, Torabi M (2013) Design, formulation and evaluation of medicinal chewing gum by the extract of Salvadora Persica. Life Sci J 10:47–55
Kralikova E, Kozak JT, Rasmussen T, Gustavsson G, Houezec JL (2009) Smoking cessation or reduction with nicotine replacement therapy: a placebo-controlled double blind trial with nicotine gum and inhaler. BMC Public Health 9:433
Aslani A, Rafiei S (2012) Design, formulation and evaluation of nicotine chewing gum. Adv Biomed Res 1:1–6
Reineccius GA (1993) Controlled release techniques in food industry. In: Risch SJ, Reineccius GA (eds) Encapsulation and controlled release of food ingredients, ACS Symposium Series, vol 590. American Chemical Society, Washington DC
Greenblatt HC, Dombroski M, Klishevich W, Kirkpatrik J, Bajwa I, Garrison W, Redding BK (1993) Encapsulation and controlled release of flavors and fragrances. In: Karsa DR, Stephenson RA (eds) Encapsulation and controlled release. Royal Society of Chemistry (RSC), London
Lew CW (2000) Encapsulation additives. US Patent 6,056,992
Taylor AJ (2002) Release and transport of flavors in vivo: physicochemical, physiological, and perceptual considerations. Comp Rev Food Sci Food Safety 1:45–57
Sostmann K, Potineni PV, McMillan E, Antenucci RN (2009) In: Hansel A, Dunkl J (eds) 4th international conference on proton transfer reaction mass spectrometry and its applications. Innsbruck, Innsbruck University Press
De Roos KB, Wolswinkel K (1994) Non-equilibrium partition model for predicting flavor release in the mouth, in trends in flavor research, proceedings of the 7th Weurman flavor research symposium, Noordwijkerhout, The Netherlands, 15-18 1993. In: Maarse H, van den Heij DJ (eds). Elsevier, Amsterdam
Harrison M (2000) Mathematical models of release and transport of flavors from foods in the mouth of the olfactory epithelium. In: Roberts DD, Taylor AJ (eds) Flavor Release. Oxford University Press, Washington, DC
Ferrazzano GF, Cantile T, Coda M, Alcidi B, Sangianantoni G, Ingenito A, Stasio MD, Volpe MG (2016) In vivo release kinetics and antibacterial activity of novel polyphenols-enriched chewing gums. Molecules 21:1–11
Hansson A, Andersson J, Leufven A (2001) The effect of sugars and pectin on flavor release from a soft drink-related model system. Food Chem 72:363–368
Roberts DD, Elmore JS, Langley KR, Bakker J (1996) Effects of sucrose, guar gum, and carboxy-methylcellulose on the release of volatile flavor compounds under dynamic conditions. J Agric Food Chem 44:1321–1326
Baek I, Linforth RST, Blake A, Taylor AJ (1999) Sensory perception is related to the rate of change of volatile concentration in-nose during eating of model gels. Chem Senses 24:155–160
Delarue J, Loescher E (2004) Dynamic of food preferences. A case study with chewing gums. Food Qual Prefer 15:771–779
Chandran S, Ravi S, Vipin KV, Augusthy AR (2014) Formulation and evaluation of medicated chewing gums containing methyl prednisolone IP. Int J ChemTech Res 6:4810–4816
Ko S, Gunasekaran S (2014) Controlled release of food ingredients. In: Nano- and micro-encapsulation for foods. Wiley, Chichester, pp 325–343
Peltzer MA, Salvay AG, Delgado JF, Wagner JR (2017) Use of edible films and coatings for functional food developments: a review. In: Functional foods: sources, health effects future perspectives. Nova Science Publishers, New York, pp 1–26
Charanioti C, Nikoloudaki A, Tzia C (2015) Saffron and beetroot extracts encapsulated in maltodextrin, gum arabic, modified starch and chitosan: incorporation in chewing gum system. Carbohyd Polym 127:252–263
Arvanitoyannis IS, Varzaka TH (2008) Vegetable waste management: treatment methods and potential uses of treated waste. In: Arvanitoyannis IS (ed) Waste management for the food industries. Elsevier. Academic Press, London
Aguiar J, Estevinho BN, Santos L (2016) Microencapsulation of natural antioxidants for food application – the specific case of coffee antioxidants – a review. Trends Food Sci Technol 58:21–39
Nakagawa K (2014) Nano- and microencapsulation of flavor in food systems. In: Kwak HS (ed) Nano- and microencapsulation for foods. Wiley, Oxford
Marquez AL, Perez MP, Wagner JR (2017) Double emulsions: potential applications for the elaboration of functional foods. In: Nelson DL (ed) Functional foods: sources, health effects and future perspectives. Nova Science Publishers, New York
Mohos F (2010) Confectionery and chocolate engineering: principles and applications. Willey, Oxford
Minifie BW (1989) Chocolate, cocoa and confectionery: science and technology, 3rd edn. AVI Book, New York
Rey A, Gonzalez R, Martinez-de-Juan JL, Bendito J, Mulet A (2007) EMG assessment of chewing gum behaviour for food evaluation: influence of personality characteristics. Food Qual Prefer 18:585–595
Dawes C, Pedersen AML, Villa A, Ekström J, Proctor GB, Vissink A, Aframian D, McGowan R, Aliko A, Narayana N, Sia YW, Joski RK, Jensen SB, Kerr AR, Wolf A (2015) The functions of human saliva: a review sponsored by the world workshop on oral medicine VI. Arch Oral Bio 60:863–874
Katschinski M (2000) Nutritional implications of cephalic phase gastrointestinal responses. Appetite 34:89–96
Engelen L (2004) A rough guide to texture. Oral physiology and texture perception of semi solids. Dissertation, University of Utrecht
Ting Y, Jiang Y, Ho CT, Huang Q (2014) Common delivery systems for enhancing in vivo bioavailability and biological efficacy of nutraceuticals. J Funct Foods 7:112–128
Yang Y, Yin J, Shao B (2011) Simultaneous determination of five aluminum lake dyes in chewing gum by HPLC with photodiode array detection. Food Addit Contam 28:1159–1167
Tedesco MP, Monaco-Lourenço CA, Carvalho RA (2017) Characterization of oral disintegrating film of peanut skin extract-potential route for buccal delivery of phenolic compounds. Int J Biol Macromol 97:418–425
Watanabe S, Dawes C (1988) The effects of different foods and concentrations of citric acid on the flow rate of whole saliva in man. Arch Oral Biol 33:1–5
Heintze U, Birkhed D, Björn H (1983) Secretion rate and buffer effect of resting and stimulated whole saliva as a function of age and sex. Swed Dent J 7:227–238
Richardson CT, Feldman M (1986) Salivary response to food in humans and its effect on gastric acid secretion. Am J Phys 250:G85–G91
Edgar M, Dawes C, O’Mullane D (2004) Saliva and oral health, 3rd edn. BDJ Books, London
Dawes C, Macpherson LMD (1992) Effects of nine different chewing gums and lozenges on salivary flow rate and pH. Caries Res 26:176–182
De Almeida PDV, Gregio AMT, Machado MAN, De Lima ADS, Azevedo AAS, Azevedo LR (2008) Salvia composition and functions: a comprehensive review. J Comtemp. Dent Pract 9:72–80
Woolnough JW, Bird AR, Monro JA, Brennan CS (2010) The effect of a brief salivary a-amylase exposure during chewing on subsequent in vitro starch digestion curve profiles. Int J Mol Sci 11:2780–2790
Neyraud E, Palicki O, Schwartz C, Nicklaus S, Feron G (2012) Variability of human saliva composition: possible relationships with fat perception and liking. Arch Oral Biol 57:556–566
WL X, Lewis D, Broundloud JE, Morgenstern MP (2008) Mechanism, design and motion control of a linkage chewing device for food evaluation. Mech Mach Theory 43:376–389
Lucas PW (2004) The structure of the mammalian mouth. In: Dental functional morphology: How teeth work. Cambridge University Press, Cambridge
Lucas PW (2004) How the mouth operates. In: Dental functional morphology: How teeth work. Cambridge University Press, Cambridge
Mongini F, Tempia-Valenti G, Benvegnu G (1986) Computer-based assessment of habitual mastication. J Prosthet Dent 55:638–649
Blee N, Linforth R, Yang N, Brown K, Taylor A (2011) Variation in aroma release between panelists consuming different types of confectionary. Flavour Fragr J 26:186–191
Lucas PW (2004) Tooth shape. In: Dental functional morphology: How teeth Work. Cambridge University Press, Cambridge
Krause AJ (2010) Real-time release of volatile and non-volatile components from chewing gum using a mechanical chewing device. Dissertation, University of Minnesota
Anderson K, Throckmorton GS, Buschang BH, Hayasaki H (2002) The effects of bolus hardness on the masticatory kinematics. J Oral Rehabil 29:689–696
Peyron MA, Lassauzay C, Woda A (2002) Effects of increased hardness on jaw movement and muscle activity during chewing of visco-elastic model foods. Exp Brain Res 142:41–51
Foster K, Woda A, Peyron M-A (2006) Effect of texture of plastic and elastic model foods on the parameters of mastication. J Neurophysiol 95:3469–3479
Wu B, Kulkarni K, Basu S, Zhang S, Hu M (2011) First-pass metabolism via UDP-glucuronosyltransferase: a barrier to oral bioavailability of phenolics. J Pharm Sci 100:3655–3681
Mallery SR, Budendorf DE, Larsen MP, Pei P, Tong M, Holpuch AS, Larsen PE, Stoner GD, Fields HW, Chan KK, Ling Y, Liu Z (2011) Effects of human oral mucosal tissue, saliva, and oral microflora on intraoral metabolism and bioactivation of black raspberry anthocyanins. Cancer Prev Res 4:1209–1221
Satheesh Madhav NV, Shakya AK, Shakya P, Singh K (2009) Orotransmucosal drug delivery systems: a review. J Control Release 140:2–11
Mizrahi B, Domb AJ (2008) Mucoadhesive polymers for delivery of drugs to the oral cavity. Rec Pat Drug Deliv Formul 2:108–119
Martins ICF, Raposo NRB, Mockdeci HR, Polonini HC, de Oliveira FA, Fabri GMC, das Graças AMCM (2017) Delivering resveratrol on the buccal mucosa using mucoadhesive tablets: a potential treatment strategy for inflammatory oral lesions. Curr Drug Deliv. https://doi.org/10.2174/1567201814666170726102558
Wang ST, Chou CT, Su NW (2017) A food-grade self-nanoemulsifying delivery system for enhancing oral bioavailability of ellagic acid. J Funct Foods 34:207–215
Pagare PK, Satpute CS, Jadhav VM, Kadam V (2012) Medicated chewing gum: a novel drug delivery system. J Appl Pharm Sci 2:40–54
Ginsburg I, Koren E, Shalish M, Kanner J, Kohen R (2012) Saliva increases the availability of lipophilic polyphenols as antioxidants and enhances their retention in the oral cavity. Archives Oral Biol 57:1327–1334
Trivedi H, Xu T, Worrell C, Panaligan K (2005) US Patent 11/256,861
Jacobsen J, Bjerregaard S, Pedersen M (1999) Cyclodextrin inclusion complexes of antimycotics intended to act in the oral cavity–drug supersaturation, toxicity on TR146 cells and release from a delivery system. Eur J Pharm Biopharm 48:217–224
Kamonpatana K, Failla ML, Kumar PS, Giusti MM (2014) Anthocyanin structure determines susceptibility to microbial degradation and bioavailability to the buccal mucosa. J Agri Food Chem 62:6903–6910
Smith AJ, Moran J, Dangler LV, Leight RS, Addy M (1996) The efficacy of an antigingivitis chewing gum. J Clin Periodontol 23:19–21
Blumenthal G (2005) US Patent 11/166,543
Ooshima T, Minami T, Aono W, Tamura Y, Hamada S (1994) Reduction of dental plaque deposition in humans by oolong tea extract. Caries Res 28:146–149
Edgar KJ, Buchanan CM, Debenham JS (2001) Advances in cellulose ester performance and application. Prog Polym Sci 26:1605–1688
Greenberg M, Urnezis P, Tian M (2007) Compressed mints and chewing gum containing magnolia bark extract are effective against bacteria responsible for oral malodour. J Agric Food Chem 55:9465–9469
Gelski J (2006) Tea’s weight loss potential cited as additional benefits. Food business News 28:38–40
Lee MJ, Lambert JD, Prabhu S, Meng X, Lu H, Maliakal P, Ho CT, Yang CS (2004) Delivery of tea polyphenols to the oral cavity by green tea leaves and black tea extract. Cancer Epidemiol Biomark Prev 13:132–137
Blair DW (2010) Use of starch inclusion complexes for improved delivery of dietary polyphenols to the oral cavity by chewing gum. Dissertation, the Pennsylvania State University
Aslani A, Ghannadi A, Rostami F (2016) Design, formulation and evaluation of ginger medicated chewing gum. Adv Biomed Res 5:130
Kehayoglou A, Doxastakis G, Kiosseoglou V (1994) Compressional properties of Chios mastic. In: Charalambous G (ed) Food flavors, ingredients and composition, proceedings of the 7th international flavor conference Samos, Greece, 1993. Elsevier, Amsterdam
Paraskevopoulou A, Kiosseoglou V (2016) Chios mastic gum and its food applications. In: Kristbergsson K, Otles S (eds) Functional properties of traditional foods. Springer, New York
Gluskin AE, Qazi MW (2006) US Patent 11/887,284
Mostafavi SA, Varshosaz J, Arabian S (2014) Formulation development and evaluation of metformin chewing gum with bitter taste masking. Adv Biomed Res 3:92
Porsgaard TK (2005) US Patent 12/159,524. https://www.google.com/patents/US20080299250
Liping L, Xihui Z (2009) Chinese Patent CN 200810114357. http://www.google.com/patents/CN101595935A?cl=en
Si H (2016) Chinese Patent CN 201610642022. https://www.google.com/patents/CN106260468A?cl=en&hl=tr
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Palabiyik, I., Pirouzian, H.R., Konar, N., Toker, O.S. (2018). A Novel Delivering Agent for Bioactive Compounds: Chewing Gum. In: Mérillon, JM., Ramawat, K. (eds) Bioactive Molecules in Food. Reference Series in Phytochemistry. Springer, Cham. https://doi.org/10.1007/978-3-319-54528-8_32-1
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