Journal of Korean Society of Oral Health Science 2017, September. 5(2): 8~15 ISSN: 2288-6079 유제품에의한구강내 ph 변화와우식활성능에관한평가 김현대 동부산대학교치위생과 An evaluation in changes of ph and dental caries activity in oral cavity due to dairy products Hyun-Dae Kim Department of Dental Hygiene, Dongpusan College University Correspondence to Kim H-D, Tel: +82-51-540-3823 Fax: +82-51-540-3676 E-mail: hydkim9710@hanmail.net Received Aug 9, 2017 Revised Aug 28, 2017 Accepted Sep 11, 2017 ABSTRACT In this study, ph value, buffer capacity and total sugar contents (Brix %) were measured by selecting food & beverages containing lactic acid bacteria in viscous form and inviscid form as an ex vivo study to reproduce similar phenomena with regard to oral hygiene during and after oral ingestion. Further, the dental caries activity of Streptococcus mutans was measured to analyze factors affecting tooth corrosion and dental caries in oral cavity after inoculating Streptococcus mutans into selective samples of the experiment and control groups. Compared to processed milk products, the ph of viscous yogurt to which distilled water was added showed a low measurement. Each ph was in the range of 4.11-4.21 and 6.73-6.91. Compared to the processed milk product, the ph of viscous yogurt to which oral cavity cleaner was added showed a low measurement. It was even lower than in the case where distilled water was added as a solution ex vivo. Further, the buffer capacity of yogurt product as an experiment group was measured to be in the range of 0.40-0.51 ml at ph 5.5. The range of total sugar contents (%) of yogurt to which distilled water was added as a solution was 11.0-14.5, which was higher than that of processed milk product(9.0-12.0). In the case where oral cavity cleaner was added as a solution, sugar content(%) was higher in all samples than the cases where distilled water was added. In analysis of the vitality of Streptococcus mutans in yogurt-2 products, the experiment group with the lowest ph value and white milk product, the control group, the number of germs increased within 10 hours of culture time, after which it decreased. However, in the case of the control group, the number of total germs gradually increased with increasing culture time. The result of this study implies that viscous yogurt product to which distilled water and oral cavity cleaner is added as a solution is likely to cause tooth corrosion and dental caries, because its ph value and sugar content (%) is higher than that of processed milk product. Oral hygiene, therefore, should also be controlled after ingesting processed milk product. Key words: Caries activity, Dairy products, Oral cavity, ph change I. 서론 최근건강수명에대한관심증가와양성평등시대에접어들 어혼식생활문화가저변확대됨에따라식음료선택에있어다품종, 소량형태의고열량, 고단백및고지방식으로변화하고있다. 이러한형태의섭취식품들은정제도가높아질병양 Copyright@ 2017 by the Korean Society of Oral Health Science (KOHS) 8
An evaluation in changes of ph and dental caries activity in oral cavity due to dairy products 상도다양화되고있다. 치아우식증은다른질환과는달리한번이환되면만성적으로진행되어원래상태로되돌릴수가없으므로무엇보다조기예방이중요한질병이다 [1]. 치아우식증은구강미생물이생산하는유기산에의해치아경조직의조성물인수산화인회석이분해되어칼슘과인같은무기질이빠져나가면생기는결과물이다 [2]. 치아우식과탄수화물의섭취가밀접한관계를가지고있는데, 가장우식유발을시키는 sucrose은용해도가높고, 치태내로확산이쉬워서세포외다당체와산을생산하는원료로공급된다. 구강내치아우식균인 Streptococcus mutans는 sucrose으로부터불용성 glucan을생산하여구강내세균의부착에관여하며, 치태에존재하는세균집락들의부착을더욱견고하게하여치태의형성에주요인이된다 [3]. 또한, 구강내의치은열구는산소농도가매우낮아이곳에서식하는구강세균들은발효를통해 ATP를생산하는데, 치태에존재하는 Streptococcus mutans에의해 sucrose가 fructose 와 glucose으로분해되어대사내해당작용을통해최종유기산을생성한다. 이러한유기산의 ph가 5.5 이하로떨어지면서법랑질의수산화인회석결정체가분해되거나탈회가일어나치아우식증을유발한다 [4]. 법랑질을이화학적으로탈회시키는기전으로치아우식증과치아부식증의병변결과는유사하지만각기다른원인물질에의해발생한다는점이차이가있다. 일반적으로치아부식증은산업현장에서발생한산의가스나미스트 (mist) 가치아에작용하여나타나는직업성치아부식증등이있다. 그리고산성과일이나산성식음료등에포함된산성물질의발생이원인이되어치아변색과치질의결손을나타내는식이성치아부식증있는데 [5], 이러한산성식음료가식이성치아부식증에주요한영향을미친다는보고는이미선행연구들을통해입증되어왔고 [6][7][8], 그외보다구체적으로사람의치간치태에서 ph를 5.5 이하로떨어뜨리는치아우식성유발식품으로콜라음료, 우유, 초콜릿우유, 사과음료, 파스타, 감자칩, 쌀밥등이포함되어있는것으로알려져있다 [9]. 건강기호식품중우유를주원료로종균을접종시켜가공제조한발효요구르트는건강장수식품으로서방세계에서우리나라로급속히전파되어그소비량이증가된대표적인것이다. 따라서국내에서많이소비는액상요쿠르트제조에사용되는균주로는 Lactobacillus sp. 인데, 통성혐기성으로유제품, 채소등에서식하고일부균종은사람이나동물의구강, 위장 관및여성생식기와같은산성환경에잘공생하면서구강내치아우식기전과연관이있는것으로알려져있다 [3]. 이러한젖산균 (Lactic acid bacteris) 은 Louis Pasteur에의해처음발견되었고 sucrose을발효하여젖산을주로생산하는세균으로그람양성의구균, 구형간균, 간균등의세포형태를가지고있으며, DNA의 G+C 함량이 50% 이하인세균들을말한다 [10]. 여기에분류학적으로 Lactobaciilus sp., Streptococcus sp., Lueuconostoc sp., Pediococcus sp. 및 Bifidobacterium sp. 등이속한다 [11]. 치아우식증의주요한원인세균인 Streptococcus mutans는산소성조건에서는주로 glucose과같은당을발효하여에너지를얻으며대사산물로젖산 (lactic acid) 만을생산하며소량의 glucose가있는무산소성조건에서는주로 acetate, formate 과 ethanol을생성한다. 이중에서젖산은강산으로치면세균막내에접촉되면 ph 5.5 이하로떨어져치아경조직의수산화인회석을분해시켜치아우식유발에중요한요인으로작용한다 [12]. 따라서식품과치아경조직간의치아우식발생의관련성을규명하는데있어식품의우식유발능측정이필수적인데, 동물우식모형과세균막 ph 측정모형및구강내우식유발모형이대표적인것으로알려져있다 [13]. 그러나치아경조직의치아우식발생에중요한요소인세균막의 ph의변화를측정하는것이가장효과적인것으로보고되고있다 [14]. 수종의젖산균발효유에대한연구에서발효유의 ph가높을수록치아의우식활성능이증가하는식품으로분류하였으나 [15], 발효유에접종된젖산균은치아우식균의증식이나치태형성을억제하는효과가있는것으로보고하였다 [16]. 지금까지치아우식증과치주질환에영향을주는식품군에대한연구와일부생활식음료가치아부식및우식에미치는영향에대한연구보고는다양하게알려져있다. 따라서건강한수명의질개선의차원에서건강기호식음료의선택적소비증가형태는지속될수밖에없는실정이므로이들식음료섭취시구강내치아표면의노출시간을감안할때이화학적으로치아법랑질표면의부식과우식기전에영향을미치는요인에대해파악해볼필요가있다. 따라서본연구에서는호상형태와비호상형태의유산균식음료를실험군과대조군으로나누어섭취시와섭취후생체외연구로각각실시하였다. 음용상태의재현은시료에증류수를용매로첨가하였고, 음용후구강세정상태의재현은각 9
Journal of Korean Society of Oral Health Science Vol. 5 No. 2 September 2017 시료에구강세정제를용매로일정비율희석액으로제조하여각각 ph 수치, 완충능및총당도 (Brix%) 를측정하였다. 또한, 실험군과대조군의선택적시료에 Streptococcus mutans 균을접종시킨후치아우식균의우식활성능을측정하여구강내치아부식과우식에미치는영향을분석하였다. 이러한결과를토대로치아부식과우식유발활성이낮은일부유제품을선택할수있게하여유아와장애인의구강관리에대한적절한정보제공과올바른치위생식이조절프로개발에기초자료로제공하고자실시하였다. Ⅱ. 연구방법 1. 시료의선정 본실험에서사용된시료들은치아법랑질에치아부식이나치아우식을유발시킬수있는호상과비호상형태의유제품중원유를가공한요구르트와우유제품을선정하였다. 실험군으로호상형태의요구르트 3개제품과대조군으로우유가공식음료 3개제품을국내유통업체점에서구입하여냉장보관한후바로실험에적용하였다. 2. ph 변화측정각시료의 20ml를동일한온도조건하 (37 ) 에서 ph를측정하기위해배양기에서조정한후 ph meter(waterpfoof phscan3, Eutech, Instruments Pte Ltd, Singapore) 를사용하였다. ph meter의전극은표준완충액으로보정한후각시료를증류수와구강세정액 (biotene, Canada,; glycerin, xylitol, sorbitol, propylene, glycol, poploxamer 407, sodium benzoate, hydroxyethylcellulose, methylparaben, propylparaben flavor, sodium phosphate, purified water) 의 20% 희석액을제조한후 ph 측정을총 3회실시하여평균값으로산출하였다 [17]. 3. 완충능측정각시료의 20ml의 20% 희석액비커에담아균질혼합후 ph가 5.5이하인경우는 1 M sodium hydroxide solution을이용하여 ph 5.5까지상승될때까지의사용된 sodium hydroxide solution의양을측정하여시료의완충능력을환산하였다 [6]. 4. 총당도측정 <Table 1> Products of experimental and control group used in the experiments Classification Brand name Main Ingredients crude milk, mixed nonfat dry milk P-Yogurt 3) protein concentrate powder, lactic acid bacteria Experimental group 1) Control group 2) M-Yogurt crude milk, plain syrup, mixed nonfat dry milk, lactic acid bacteria, crude milk, nonfat dry milk, N-Yogurt peach juice concentrate, lactic acid bacteria, B-White milk crude milk 100% P-Strawberry-flavored milk D-Chocolate-flavored milk crude milk 65%, nonfat dry milk, strawberry juice concentrate crude milk 20%, nonfat dry milk, cream, cocoa powder, chocolaty. 스포이트를사용하여당도굴절계의접안렌즈에시료를 2-3방울떨어뜨린후프리즘덮개를덮고 30초간기다렸다가흰색으로눈금이변하면당도 (Brix 범위 0-32%) 를측정하였다 (Hand refractometer ATC-1, Atago, Japan). 5. S. mutans의우식활성능각시료를교반시킨후 ph 5.5까지 1M sodium hydroxide solution으로적정시켰다. 적정된각시료에 Streptococcus mutans (KCCM 40105) 를접종혼합시킨후 0, 1, 5, 10, 24hrs 동안 37, incubator에서배양하였다. 시간대별각시료를일정량분주하고 10 7 배까지희석시켜 MS(Mitis Salivarius, Difco) agar상에도말접종후 37, 48hrs 동안배양한후각시간대별시료에대한 colony를측정하였다 [18]. 1) Experimental group: Viscous type of liquid yogurt products 2) Control group: liquid milk products 3) Abbreviated word means name of products 10
An evaluation in changes of ph and dental caries activity in oral cavity due to dairy products 1. 시료의이화학적특성 1) 실험유제품의 ph 분석 Ⅲ. 연구결과 실험군인호상요구르트와대조군인우유가공식품에각각증류수와구강세정액을용매로일정비율희석하여초기 ph 수치를측정한결과는 <Table 2> 과같았다. 상온에서구강내음용상태를재현하기위하여증류수 (ph 6.30±0.15) 와구강세정제 (ph 6.45±0.11) 을실험군과대조군에 20% 희석액으로제조하였다. 각시료에증류수를용매로희석한결과실험군과대조군의 ph 범위는 4.11-4.47과 6.73-6.91로나타났다. 호상요구르트에증류수를용매로첨가한실험군이대조군에비해치아법랑질의탈회임계선인 ph. 5.5 이하로우유가공제품보다낮은 ph를보였다. 한편, 실험군과대조군에구강세정액을용매로희석하여전자와동일한방법으로 ph를측정한결과실험군 ( 요구르트제품 ) 의경우증류수를용매로첨가한것보다 ph 범위 (4.24-4.58) 가다소상승한것으로나타났고대조군 ( 우유가공품 ) 의경우증류수를용매로첨가한시료보다다소낮은수준의 ph 변화가있었다. <Table 2> The results of ph values between experimental group and control used in this study Brand name ph in D.W. 1) ph in O.R. 2) P-Yogurt 3) 4.47(0.01) 4) 4.58(0.03) M-Yogurt 4.11(0.01) 4.24(0.04) N-Yogurt 4.21(0.02) 4.32(0.05) B-White milk 6.73(0.02) 6.68(0.05) P-Strawberry-flavored milk 6.85(0.01) 6.72(0.06) D-Chocolate-flavored milk 6.91(0.02) 6.80(0.04) 1) ph in D.W. menas ph in distilled water 2) ph in O.R. menas ph in oral rinse 3) Abbreviated word means name of products 4) All values are mean(standard deviation) 2) 실험유제품완충능분석 <Table 3> 은각시료를 ph 5.5까지상승시키는데필요한 1 M sodium hydroxide solution의양을단일측정한수치를나타내고있다. 대조군인우유제품은 <Table 2> 에서제시된바와같이 ph가 5.5이상이므로분석에적용되지않았고, 실험 군인요구르트제품의완충능의범위는 0.40-0.51ml로나타나거의비슷한수준이었다. 실험에적용된요구르트의완충능은 ph 5.5에서 P-요구르트 0.51ml, M-요구르트 0.44ml및 N- 요구르트 0.40 ml로나타났다. <Table 3> The results of NaOH( ml ) required to raise the ph of 5.5 ph in D.W. Brand name T.A. 5.5 1) P-Yogurt 3) 0.51 M-Yogurt 0.44 N-Yogurt 0.40 B-White milk ND 2) P-Strawberry-flavored milk ND D-Chocolate-flavored milk ND 1) T.A. 5.5 menas titratable acidity to ph 5.5 2) All values are mean and ND is not determined 3) Abbreviated word means name of products 3) 실험유제품의총당도 (Brix %) 분석 실험군인요구르트제품 3종류와대조군인우유가공품 3종류의총당도 (Brix %) 를측정한수치는 <Table 4> 와같다. 증류수를희석한유제품중에서요구르트의총당도 (%) 범위는 11.0±0.03 14.5±0.06으로우유제품 (9.0±0.02 12.0±0.03) 보다높게나타났다. 분석시료중에서 P-요구르트의총당도가 14.5±0.06% 으로가장높았고 B-흰우유가가장낮은수치 (9.0±0.02%) 를보였다. 또한우유제품중에서는 D-초코레트우유제품이 12.0±0.03% 로가장높은총당도수치를보여유제품에포화된설탕의함량과비례하는것으로나타났다. 반면, 구강세정제를희석한유제품의총당도는증류수를희석한시료보다모두높은당도수치를보였다. 실험군의총당도 (%) 범위 (15.5±0.03 18.5±0.05) 는대조군인우유제품보다높게나타났다. <Table 4> The results of sugar content (Brix %) measurement index of samples Brand name Sugar(%) in D.W. 1) Sugar(%) in O.R. 2) P-Yogurt 3) 14.5(0.06) 16.0(0.02) M-Yogurt 11.0(0.03) 15.5(0.03) N-Yogurt 12.5(0.03) 18.5(0.05) B-White milk 9.0(0.02) 14.0(0.05) P-Strawberry-flavored milk 10.0(0.02) 14.5(0.05) D-Chocolate-flavored milk 12.0(0.03) 17.0(0.04) 11
Journal of Korean Society of Oral Health Science Vol. 5 No. 2 September 2017 1) Sugar in D.W. menas ph in distilled water 2) Sugar n O.R.. menas ph in oral rinse 3) Abbreviated word means name of products 4) 실험유제품에대한 S. mutans 의생활력분석 1M sodium hydroxide solution으로 ph 5.5으로적정된각시료중에서 ph 수치가가장낮은요구르트두제품과흰우유제품을선정하여 Streptococcus mutans를접종시킨후평판배지상의세균수를측정한결과요구르트두개제품에서 0-10 incubation time(hrs) 까지는총세균수가증가하였다가 10시간이후부터세균수가감소되었다 <Table 5>. 특히배양시간 10시간대에최대총세균수를보였다. 한편, 흰우유제품의경우배양시간이증가할수록총세균수가서서히증가하였는데, 배양시간에따른총세균수는 5.16±0.06에서 6.02±0.12 log10 CFU/ ml까지범위의값을나타났다. <Table 5> The cell forming unit(cfu) of Streptococcus mutans for different groups by incubation time Unit: log10 CFU/ ml Incubation Brand name time(hrs) M-Yogurt N-Yogurt B-White milk 0 4.75(0.02) 1) 4.48(0.03) 5.16(0.06) 1 4.75(0.16) 4.51(0.11) 5.45(0.14) 5 5.15(0.05) 4.98(0.04) 5.56(0.02) 10 5.02(0.01) 4.90(0.01) 5.71(0.16) 24 4.58(0.03) 4.74(0.12) 6.02(0.12) 1) All values are mean(standard deviation) Ⅳ. 고찰 최근구강건강에대한관심이높아지면서안전한식음료선택에대한욕구가점차강해지고있다. 섭취하는식음료는아동의성장과성인의건강유지에매우중요한역할을할뿐만아니라구강질환예방과구강건강을유지하는데필수적이다 [1]. 치아우식증유발요인으로치아표면의감수성, 구강내치아우식성세균, 치아우식성탄수화물및타액분비속도및조성등이복합적으로작용하는데이중에서단순탄수화물은치아우식증의발생에가장중요한인자이다 [9]. 치아우식의대표적인세균인 Streptococcus mutans는치아 면에부착능력이좋아전분, 유당, 설탕, 포도당, 과당과같은탄수화물을대사시켜수산화인회석의탈회에영향을미치는젖산뿐만아니라피르부산 (pyruvic acid) 와개미산 (formic acid) 들생성하여치아우식발생을유도시킨다. 그리고소량의포도당이있는무산소성조건하에서는강산인아세트산염 (acetate), 포름산염 (formate) 이생성되는데이들산성생성물질이치면세균막내에쌓이면치면의 ph가 5.5 이하로떨어져수산회인회석이분해된다. 이러한 S. mutans는적정 ph가낮은 F-ATPase(proton pump) 를가지고있어낮은산성환경에서생존할수있다 [19]. 따라서아동과성인의건강기호식음료인요구르트와우유가공식품이이화학적요인과치아우식세균에의해치아법랑질의부식과우식에영향이클것으로판단되어올바른치위생식이조절프로그램개발에기초자료로제공하는것이필요하다고판단되었다. 본연구에서는생체외연구로호상형태의요구르트제품과비호상형태의우유가공품을구강내섭취할때와섭취후구강위생환경개선을위하여구강세정작용현상을유사하게재현시키기위해기존연구자료를토대로응용실험하였다 [6]. 실험유제품의 ph 분석에서음용상태를재현하기위하여요구르트제품과우유가공품에증류수를용매로일정비율희석하여 ph 수치를측정한결과우유가공품보다요구르트제품들의 ph 수치가낮게측정되었고실험군인요구르트제품모두법랑질탈회임계선인 ph 5.5 이하로나타났다. 반면에대조군인흰우유, 딸기우유, 초콜릿우유모두 ph 5.5 이상으로측정되었다. Ji와 Park[20] 의연구에서흰우유는 ph 6, 요구르트와요플레는각각 ph 3과 4 범주내에나타났고, Jeong 등 [10] 의선별균주에의해제조된요구르트를배양시간에따라측정한 ph 변화연구에서는요구르트발효가진행되면서배양 6시간후 ph 6.3, 12시간배양후 ph 5.7, 24시간후 ph 4.1까지완만하게떨어졌다고하였다. Lee 등 [21] 은요구르트의저장중품질변화에서요구르트의적당한 ph는 4.1-4.2 범위라고발표하였다. 그리고치과예방학적인측면에서치아법랑질주위의 ph가 4.5-5.5인경우치아우식증이발생될수있고, ph 4.5 이하인경우치아부식증이, ph 5.5 이상에서는재광화가일어날수있다고보고하였다 [22]. 본실험에서는각시료에증류수를용매로첨가한 20% 희석혼합액상태에서측정된결과이지만, 전자의기존연구결과들과유사한 ph 범위수치를나타내었다. 특히요구르트제 12
An evaluation in changes of ph and dental caries activity in oral cavity due to dairy products 품들은유산균의접종에의해배양된발효음료로원유가 100% 포함된흰우유나식품첨가물이혼합된우유가공식음료에비해 ph수치범위가약산성으로나타난것으로판단된다. 젖산세균들은대체로산에대한내성이강한균주들로이루어져있는점을감안할때 [10], 본실험결과에서제시된바와같이우유가공품보다요구르트제품을섭취한후구강위생관리가매우중요하며특히아동과장애인들의치아부식과우식에대한을잠재성을고려해야할것으로사료된다. 그리고실험유제품의 ph 분석에서음용후구강위생환경을개선하기위해구강세정제를용매로일정비율희석한생체외실험결과에서실험군인요구르트제품모두법랑질탈회임계선인 ph 5.5이하로나타났지만, 대조군인모든우유가공품들은증류수를희석한경우와동일하게 ph 5.5이상의측정치를보였다. 또한, 실험군과대조군모두증류수로희석한시료보다구강세정액을첨가한시료에서모두 ph수치가다소낮게나타났다. 일부선행연구 [6] 에서구강양치액의부식능력을규정하고있는데치아의부식을초래할수있는구강양치액의 ph 수치를 5.5로규정하고있는데, 산성식음료섭취후구강양치액으로세척하는것보다먹는물로세정하는것이구강건강관리측면에서양호할것으로판단된다. 구강관리용품에대한국제적인표준기준을제정하는기관인 ISO TC106 SC7 WG4에서는구강양치액과관련된국제적인기준을제정하고있다. 구강양치액의 ph는 3.0에서 10.5사이에존재해야한다고규정하고있고특히 ph가 5.5이하인제품인경우치아표면을부식시킬가능성이있기때문에구강양치액선택시이와관련된별도의부식가능성평가시험을확인하는것이필요하다고사료된다 [23]. 실험유제품의완충능분석에서법랑질탈회임계선이 ph 5.5 이하로측정된시료만을선정하여 ph 5.5까지상승시키는데필요한 1M KOH의양을측정하였다. 실험결과모든요구르트제품의완충능범위는 0.40-0.51 ml로나타났다. Choi 와 Yoon[24] 의연구에서저지방유의 ph의변화가 0-30일기간동안일정한수준 (ph 6.8-6.85) 을유지하는데반해적정산도의경우 20일경과시 0.34%, 저장 25-30일동안거의 0.5% 를나타나 ph와적정산도변화에있어저장기간에따라뚜렷한차이는보이지않은것으로나타났다. 그리고산성음료에의한치아부식은음료의산성도에의해크게좌우될것으로생각되나, 일반적으로산성도와치아부식이직접적으로비례하지는않는다고알려져있다. 이것은음료의산성도 가구강내에서적정산도로바뀌기때문이라고하였다. 또한, 완충능은산성음료가 ph의변화에대해저항하는성질로정의하였는데, 산성도와함께완충능이높은음료일수록구강내에서치아부식을유발하지않는적정산도로바뀌는것에대한저항력이높으며, 더심한부식을유발할수있다고보고하였다 [24]. 따라서실험시료결과 ph의변화가없다면화학적평형이일어난것으로가정할수있어이는치아부식이없는것으로평가할수있으며, 만약 ph가상승하였다면실험시료내수소이온이수산화인회석과반응한것이므로치아부식가능성이있다고할수있다 [6]. 실험유제품의총당도분석결과증류수를첨가한경우실험군인요구르트제품이대조군인우유가공품보다당도 % 가높게나타났는데, Kim 등 [25] 이보고한시판젖산균음료의치아부식에미치는영향의분석에서젖산균음료의당도는 17% 로이러한당분들은치아우식증의주원인균인 Streptococcus mutans 가치태형성에중요한요소로작용하는 dextran 과 levan을생성하는데필요한기질로작용될수있다. 또한포도당농도가증가함에따라치태내의 ph를급격히하락시킨다고하였다. 그리고젖산균음료의칼슘함량에따라법랑질의부식정도에유의한차이가있는것으로보고하였다. 본연구에서실험군과대조군의유제품에생체외실험으로증류수를용매로첨가함에따라 Kim 등 [25] 이보고한젖산균음료보다당도 % 수치는떨어지나거의유사한측정치를나타내었다. 특히우유제품의당도 % 수치에서는초콜릿우유 > 딸기우유 > 흰우유순서대로나타났는데설탕이많이함유된식음료에서총당도 % 의측정치가높아진것으로사료된다. 또한, Heo 등 [13] 의연구에서사용된초콜릿우유는점도와환원당이높아우식유발에영향을미칠가능성높다고하였다. 그리고구강세정제를용매로첨가한경우모든실험군과대조군의유제품에서당도 % 가높게측정되었는데이는구강세정제의화학첨가제인 xylitol, sorbitol 등이함유되어당도가증가한것으로판단된다. 실험유제품에대한 Streptococcus mutans의생활력분석에서실험군인요구르트제품은배양 10시간대에최대총세균수를보였다가배양 10시간이후부터서서히감소하였고, 반면에대조군인흰우유는배양시간이증가할수록총세균수도증가하였다. 본연구에서실험군과대조군모두초기배양시간동안은치아우식균수가증가하였는데, 원유에유산균을첨가하여배양한요구르트시료의경우발효과정에서유기산 13
Journal of Korean Society of Oral Health Science Vol. 5 No. 2 September 2017 이생성됨에따라치아우식세균수의증식을감소시키는데영향을미친것으로판단된다. 이와같은연구결과를뒷받침하는기존연구로당분이있는음료내에 1% 구연산과사과산을첨가한경우구강미생물의활성을억제한다는보고가있다 [26]. 또한 S. mutans의산생성능에의한 ph 평균값은 ph 5.33으로배양시간이길어질수록 ph 측정치가감소하는것으로보고하였다. 그러나치면에부착한 S. mutans은당질대사과정에서젖산과유기산을생성하는데, 이러한유기산과프래그 (plaque) 는치아의법랑질을탈회시키는원인이되기도한다 [20]. 본연구의제한점으로는특정유가공품을선택하여구강내음용시와음용후구강내환경을재현하기위한생체외연구로생체내구강생리환경을완전하게재현하지못한상황에서선택적용매로구강내 ph, 당도 % 및우식활성능을접근한점이다. 그러나이러한연구제한점에도불구하고본연구는호상요구르트와우유가공품의생체외 ph와당함량및치아우식균의우식활성능을평가함으로써부모의지속인관심과개입이필요한유아와장애인의구강관리에대한적절한정보제공과올바른치위생식이조절프로그램개발에기초자료로사용가능해질수있을것으로사료된다. Ⅴ. 결론 국내시판중인일부호상요구르트와우유가공제품에대한생체외연구결과다음과같은결론을도출할수있다. 1. 증류수를용매로첨가한호상요구르트의 ph수치는우유가공품에비해낮게측정되었으며각각의 ph 범위는 4.11-4.21 및 6.73-6.91로나타났다. 2. 구강세정제를용매로첨가한호상요구르트의 ph 범위 (4.24-4.58) 는우유가공품에비해낮게측정되었고생체외에서증류수를용매로첨가한경우보다낮았다. 3. 실험군인요구르트제품의완충능은 ph 5.5에서그범위는 0.40-0.51ml으로측정되었다. 4. 증류수를용매로첨가된요구르트의총당도 (%) 범위는 11.0-14.5으로대조군인우유가공품의 9.0-12.0보다높게측정되었고, 시료에구강세정제를용매로첨가한경우증류수를용매로첨가한경우보다모든시료에서높은당도 수치 (%) 를나타내었다. 5. ph수치가가장낮은실험군인요구르트 2제품과대조군인흰우유제품에대한 Streptococcus mutans의생활력분석에서배양 10시간까지는세균수가증가하였다가그이후부터감소하였고대조군의경우배양시간이길어질수록총세균수는서서히증가하였다. 본연구의결과를통하여증류수와구강세정제를용매로첨가한호상요구르트제품들은우유가공품에비해 ph 수치와당도 (%) 가높아치아부식과치아우식의가능성이있으며우유가공품을음용한후구강위생관리가필요한것으로사료되었다. 참고문헌 1. Choi JH, Kim DK: Relation between self-recognition of major oral disease and food intake of Korean adults. J of Korean Academy of Oral Health 33(2):201-210, 2009. 2. Cha JY, Yu YJ, Kim SY: Oral Microbiology. Medi Publishing, Korea. pp.251-252, 2016. 3. Kim KJ, Kim HS, Moon SE. et al: Oral Microbiology. DaehanNarade Publishing, Korea. pp.159-244. 2016. 4. Cole As, Eastoe JE: The formation and properties of dental plaque. IN Biochemistry and Oral Biology 2(2): 219-232, 1988. 5. Public Oral health committee: Public oral health. Komoosa, Korea. pp.130-133, 2016. 6. Kim AH, Kim YN, Kwon HK, Kim BI: Erosive potential of fruit flavored acidic candies in vitro and in vivo. J Korean Acad Dent Health 32(3):279-286, 2008. 7. Rytomaa I, Meuman JH, Koskinen J, Laakso T,, Gharazi L, Turunen R: In vitro erosion of bovine enamel caused by acidic drinks and other foodstuffs. Scand J Dent Res 96(4):324-333, 1998. 8. Song AH, Choi CH: Effect of commercial alcoholic drinks on sound enamel surface of bovine teeth. J Korean Acad Dent Health 37(4):180-186, 2013. 9. Park KG, Kim YS, Kim YJ, Park YM, Lee YY, Jeong 14
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