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1 J Korean Soc Food Sci Nutr 한국식품영양과학회지 45(9), 1293~1301(2016) 겉귀리및쌀귀리분말의입자크기별영양성분및이화학적특성 이유진 1 김진숙 2 김경미 2 최송이 2 김기창 2 1 한국과학기술연구원강릉분원천연물연구소 2 국립농업과학원농식품자원부가공이용과 Nutritional Components and Physicochemical Properties of Hulled and Naked Oat Flours according to Particle Sizes Yu-Jin Lee 1, Jin-Sook Kim 2, Kyung-Mi Kim 2, Song-Yi Choi 2, and Gi-Chang Kim 2 1 KIST Gangneung Institute of Natural Products 2 Agro-Food Resources, National Academy of Agricultural Science, Rural Development Administration ABSTRACT Hulled oat (Chohan) and naked oat (Choyang) flours were analyzed according to particle size to investigate nutritional components and physicochemical properties. Particle size of naked oat flours was larger than that of hulled oat flours. As the mesh of the crushed ones decreased, particle sizes increased in value. The content of total β-glucan was highest in hulled oat flour (4.23%) with mesh and in naked oat flour (4.26%) with mesh. Most total β-glucan was soluble β-glucan in both flours (over 76%). Total starch of hulled oat flours ( %) was higher than that of naked oat flours ( %). Whereas amylose contents showed a negative correlation with total starch contents. Contents of free amino acids increased according to particle size, and each component was dependent on each type of amino acid. Moreover, while fatty acid composition was not significant, the content of most naked oats was higher than that of hulled oats. Besides, the ratio of unsaturated fatty acids (oleic acid and linoleate) in both types of oat flours was relatively higher than that of other grains. The pasting properties of peak viscosity, trough, and breakdown showed the highest value in both oats with mesh. Further, the values of final viscosity and the setback were higher with relatively larger particle size. In addition, peak time exhibited a lower value with larger particle size, whereas it showed the opposite value for pasting temperature. Starch digestibility did not show any specific trend according to particle size, whereas expected glycemic index of hulled oats was lower than that of naked oats. Moreover, lower values were investigated at larger particle sizes. The results of this study provide basic useful information for processing of oat products to improve consumption of oats grown in Korea. Key words: oat flour, particle size, β-glucan, nutritional component, physicochemical properties 서 귀리 (Avena sativa L.) 는벼과에속하는곡류로예로부터단백질, 섬유질, 비타민및무기질이풍부하여건강식품으로인식되어왔다 (1,2). 독성과부작용이없는귀리의배유및호분층세포벽에는고분자인베타글루칸및단백다당체가다량함유되어있으며, 심혈관질환개선및항고혈압등의생리적효능이있는것으로알려져있다 (3-6). 그뿐만아니라귀리에는 tocol류를비롯한페놀화합물이다양하게존재하고있으며, 페놀을포함하는알칼로이드계물질인 avenanthramides는귀리의항산화물질로크게주목받고있다 (7,8). Received 23 May 2016; Accepted 27 June 2016 Corresponding author: Jin-Sook Kim, Agro-Food Resources, National Academy of Agricultural Science, Rural Development Administration, Wanju, Jeonbuk 55365, Korea preetyjs@korea.kr, Phone: 론 귀리는예로부터생산량의대부분을사료로이용하였으나, 최근건강에대한관심증대와더불어미국타임지가선정한세계 10대건강식품으로영양적가치를인정받아소비량이빠르게증가하고있다. 귀리는곡알그대로쌀과혼합하거나오트밀또는쿠키형태로단순히식용재료로이용되고있으며귀리를이용한가공제품을개발하기위해서는반드시제분공정이필요하다 (9). 한편귀리종실은일반적으로내영과외영이라는껍질의유무에따라껍질이제거되지않은겉귀리와껍질의제거가용이한쌀귀리로나누어진다 (10). 그러므로귀리를식용으로이용하고자할경우겉귀리보다는쌀귀리가다소유리하며영양적인측면에서도쌀귀리가우수한것으로평가받고있다 (11). 한편우리나라에서는귀리주요생산국인캐나다, 호주, 러시아등에서수입된원가가낮은수입산귀리를대부분이용하고있으며, 그소비량은매년증가하고있는추세이다 (12). 따라서국내에서는태한, 다한, 삼한, 조한과같은가을에파종하여 5월중순에수확이가능한추파형겉귀

2 1294 이유진 김진숙 김경미 최송이 김기창 리와내한성은다소약하나남부지역에서추파가가능한식용및사료겸용쌀귀리인조양, 수양등을개발하여국내자급률향상을위해노력하고있다 (13-15). 귀리에대한연구는주로귀리종실과관련하여재배및사료작물로서의품질평가 (16,17) 와귀리의기능성성분인베타글루칸의추출, 정제및함량변화, 생리활성에대해연구되어왔다 (18-21). 또한, 귀리의활용도를높이기위한연구로는발효귀리를첨가한전통된장의제조, 귀리추출물을이용한젖산음료개발및귀리분말을첨가한빵, 쿠키, 떡, 케이크, 죽등이있다 (22-25). Oh(26) 는쌀귀리분말을이용한다양한가공제품을개발하고이들의품질과관능적특성분석을통해귀리의우수성을검증하였으나, 귀리분말의입도및품종에따른기능성물질과이화학적특성에대한연구는수행하지않았다. 아울러귀리베타글루칸성분의가공처리에의한용해성과함량의변화 (5), 입도분획별베타글루칸의함량 (21) 에관한연구는있으나쌀귀리에관한연구는없는실정이다. 한편귀리에는다른곡류에비해다량의식이섬유가포함되어있으며이는위장통과시간을늦추고전분소화를지연시켜혈당지수 (glycemic index, GI) 를변화시키는요인으로서작용한다 (27). 또한, 전분의소화흡수속도는당뇨병과같은질환을예방하기위한중요한인자이므로새로운형태의전분질식품이나신가공기술을활용하여전분의소화율을낮출필요성이있다 (28). 따라서귀리를이용한다양한제품을개발하기위해서는전분소화율과상관성에대한체계적인연구가선행되어야한다. 귀리의식이섬유를이용하여밀가루를대체하였을경우전분소화지연효과가있음이확인되었으나 (29), 귀리의입도별전분의소화특성과소화율에따른 GI에대한연구는전무한실정이다. 아울러지금까지귀리에대한연구는대부분겉귀리에국한된것으로귀리를이용한가공제품제조에적합한국내산귀리분말의이화학적특성과영양성분에대한연구는거의없는실정이다. 따라서본연구에서는국내산귀리의소비를증진하고, 귀리를이용한다양한형태의가공제품개발을위한기초자료를제공하고자겉귀리 ( 조한 ) 와쌀귀리 ( 조양 ) 를각각선정하여입자크기에따른영양성분 ( 탄수화물, 아미노산및지방산조성 ) 및이화학적특성 ( 입도, 호화특성, in vitro 소화율, expected GI) 을비교분석하였다. 재료및방법실험재료본연구에사용한귀리는 2014년도전북정읍귀리명품화사업단에서생산한겉귀리 ( 조한 ) 와쌀귀리 ( 조양 ) 를국립농업과학원농업공학부에서 2013년개발한분쇄기 (pin mill) 를이용하여 mesh(425 μm), mesh(250 μm), mesh(1 μm), mesh(150 μm) 로분쇄하였으며얻어진입도별귀리분말은냉장보관하면서실험에사용하였다. 입도분석분쇄한귀리분말의입도분석은입도분석기 (HELOS, Berlin, Germany) 를이용하여귀리분말 2 g을취하여분산시킨후 3회반복하여입자의크기를측정하였다. 탄수화물분석 ( 베타글루칸, 총전분, 아밀로오즈 ) 귀리분말의총베타글루칸함량은 Megazyme β-glucan assay kit(megazyme International Ltd., Wicklow, Ireland) 을사용하여분석하였다. 불용성베타글루칸의함량은귀리분말에증류수를가하여 C에서 2시간동안초음파추출기로추출한후 5,000 rpm에서 10분간원심분리하여상층액을제거하여얻어진침전물로측정하였다. 수용성베타글루칸함량은총베타글루칸함량에서불용성베타글루칸의함량을뺀값으로나타내었다. 총전분및아밀로오즈의함량은 Megazyme total starch assay kit 및 Megazyme amylose assay kit을이용하여분석하였다. 유리아미노산함량분석입도별귀리분말의유리아미노산의함량분석은귀리분말 1 g에초순수 20 ml를첨가하여초음파처리 (50 C, 2시간 ) 한후원심분리 (5,000 rpm, 10분, 4 C) 하여상등액을분리하였다. 얻어진상등액은감압농축하여초순수 5 ml에용해한후 0.45 μm PVDF 필터 (Millipore, Darmstadt, Germany) 로여과하여시료로사용하였다. 제조된시료 10 μl에 70 μl의 AccQ-fluor borate buffer 와 20 μl의 AccQfluor reagent를혼합하여 55 C에서 10분간반응시킨후 ACQUITY TM UPLC(Waters, Milford, MA, USA) 로분석하였다. 이때시료온도와칼럼온도는각각 20 C, 55 C였으며, 칼럼은 AccQTag TM Ultra column 2.1 mm, 용매는용매 A(1:10 Dilution of AccQ Tag Ultra Eluent A, Waters) 와용매 B(AccQ Tag Ultra Eluent B, Waters)(linear gradient elution from A to B for 9.5 min) 를유속 0.7 ml/min 으로하여시료 1.0 μl를주입하여 2 nm에서측정하였다. 지방산추출및분석지방산조성은 AOAC 방법 (30) 에따라지질을 methyl ester화한후측정하였다. 먼저귀리분말을 soxhlet 추출법으로약 2시간동안에테르로추출하여지방산시료를제조하였다. 추출한지방산시료에 0.5 M NaOH/ 메탄올을첨가하여 85 C에서 10분동안가수분해한후 14% BF 3 메탄올을첨가하여 methyl ester화하였다. 여기에포화 NaCl과헥산을순차적으로넣은후상등액인헥산층에소량의무수 Na 2SO 4 를첨가하여수분을제거한다음분석시료로사용하였다. 지방산표준용액은지방산표준품 37종 (CRM47885, Supelco 37 Component FAME Mix, Supelco, Bellefonte, PA, USA) 을클로로포름에용해하여사용하였으며 flame ionization detector(fid) 가장착된 GC(Agilent 7890A series, Agilent, Palo Alto, CA, USA) 로분석하였다. 칼럼은

3 겉귀리및쌀귀리분말의입자크기별영양성분및이화학적특성 1295 Agilent J&W HP-88( m 0.25 mm i.d. 0.2 μm) 을, 오븐온도는 C에서분당 4 C씩 2 C까지올린후 35 분간유지하였다. 이때시료 1 μl를 split ratio 10:1로주입하였으며이동상가스인 N 2 의유량을 1 ml/min, 시료주입기와검출기온도는각각 250 C, 2 C로설정하여분석하였다. starch, RS) 으로나타내었다. In vitro 혈당지수 (expected glycemic index, egi) 는 Goni 등 (32) 의방법을이용하여측정하였으며귀리시료와표준물질 ( 식빵 ) 의소화율곡선의면적비율로 hydrolysis index(hi) 를계산한후 Goni 등 (32) 의계산식 (egi= hi) 으로부터 egi 값을구하였다. 호화특성분석귀리분말의호화특성은신속점도측정기 (Rapid Visco Analyser, Newport Scientific Pty, Ltd., Warriewood, Australia) 를사용하여시료 3 g을증류수 25 ml에분산시킨후측정하였다. 호화조건은초기온도를 50 C에서 1분간유지한후분당 12 C씩 95 C까지가열하여 2분 30초간유지한다음, 1분당 12 C씩 50 C까지냉각시켜 2분간유지하면서측정하였다. RVA viscogram으로부터최고점도 (peak), 최저점도 (trough), 최종점도 (final), 강하점도 (breakdown), 치반점도 (setback), peak time 및호화온도로산출하였으며점도단위는 rapid viscosity unit(rvu) 으로표시하였다. In vitro 소화율귀리분말의 in vitro 소화율은 Englyst 등 (31) 의방법을수정하여측정하였다 g의 porcine pancreatin(p- 7545, Sigma-Aldrich Co., St. Louis, MO, USA) 을증류수 4 ml에분산시키고원심분리한후 2.7 ml의상층액을분리하였다 ml amyloglucosidase(a-7095, Sigma- Aldrich Co.) 는증류수 0.4 ml와혼합한후 0.4 ml의희석된 amyloglucosidase를취하여앞서제조한 2.7 ml의 porcine pancreatin 상등액을혼합하여전분분해효소를제조하였다. 전분시료 mg에 2 ml의 0.05 M HCl과 0.01 g pepsin, 10개의유리구슬 (4 mm 지름 ) 을넣고교반한후 2 ml의 0.5 M sodium acetate buffer(ph 5.2) 와미리제조한전분분해효소 1 ml를넣은다음 37 C에서반응시켰다. 시간 (0~1분) 마다시료 (0.1 ml) 를취하여 % 에탄올용액과혼합한후 glucose oxidase and peroxidase assay kit(gago-20, Sigma-Aldrich Co.) 을이용하여 glucose 함량으로측정하였다. 측정된 glucose와총전분의함량을이용하여 20분이내에분해가되는빨리소화되는전분 (rapidly digestible starch, RDS), 20분과 120분사이에분해가되는천천히소화되는전분 (slowly digestible starch, SDS), 120분동안분해되지않는저항성전분 (resistant 통계분석본연구결과는 SPSS version 12.0K(SPSS Inc., Chicago, IL, USA) 를이용하여 3회반복하여실험한데이터를평균과표준편차로나타내었으며, 데이터는분산분석 (oneway ANOVA) 을시행하고유의성검정은 Duncan's multiple range test를실시하여 P<0.05 수준에서검정하였다. 결과및고찰입도분석겉귀리와쌀귀리를이용한입도별귀리분말을제조하기위하여분쇄기의배출체종류를달리하여각각,,, mesh로분쇄한후얻어진귀리분말을입도분석기로분석하였으며그결과는 Table 1과같다. 쌀귀리 (42.77~ μm) 가겉귀리 (32.66~ μm) 보다입자크기가전반적으로높게나타났으며분쇄 mesh가작을수록입도가큰경향을나타내었다. 즉겉귀리는 mesh( μm)> mesh(57.15 μm)> mesh(36.58 μm)> mesh (32.66 μm) 였으며, 쌀귀리는 mesh( μm)> mesh(64.70 μm)> mesh(43.98 μm)> mesh(42.77 μm) 순으로평균입자크기가작은것을확인하였다. 또한, 귀리품종에관계없이 mesh와 mesh는유의적인차이를나타내지않았다. 수용성, 불용성및총베타글루칸함량귀리의주된기능성물질인베타글루칸은귀리의세포벽에많이함유되어있으며가공처리에의해용해성및함량이변화되기때문에식품이용에있어매우중요한성분이다 (20). 또한, 베타글루칸은혈중콜레스테롤의함량을저하하는물질로서수용성과불용성으로구분되며 (3), 입도별귀리분말의베타글루칸함량을분석한결과는 Table 2와같다. 총베타글루칸함량은겉귀리 3.20~4.23%, 쌀귀리 3.~ 4.26% 로입자크기에따라겉귀리는 mesh를제외하고입자가작을수록함량이낮게나타났지만쌀귀리는증가하 Table 1. Particle size of oat flours in different particle sizes Hulled oat Naked oat Particle size (μm) mesh mesh mesh mesh ±9.23 a 57.15±2.91 b 36.58±1.68 c 32.66±0.50 c ±10.93 a 64.70±0.87 b 42.77±2.57 c 43.98±3.56 c Values with the different letters (a-c) in each row are significantly different at P<0.05.

4 1296 이유진 김진숙 김경미 최송이 김기창 Table 2. Contents of β-glucan of oat flours in different particle sizes Hulled oat Naked oat β-glucan (%, dry basis) Total Insoluble Soluble 4.02±0.23 ab 0.37±0.03 b ±0.43 a 0.58±0.00 ab ±0.00 bc 0.81±0.10 a ±0.08 c 0.72±0.17 a ±0.15 ab 3.±0.54 b 3.68±0.05 ab 4.26±0.04 a 0.37±0.01 b 0.59±0.10 ab 0.77±0.15 a 0.±0.13 a Values with the different letters (a-c) within a column differ significantly (P<0.05). 1) Soluble β-glucan as percent of total β-glucan Solubility (%) 1) 는경향을보였다. 겉귀리의경우 mesh(4.23%), 쌀귀리는 mesh(4.26%) 에서가장높은함량을나타내어귀리의입자가커질수록총베타글루칸함량이증가하였다 (21) 는결과와는다소차이가있었다. 한편지용성베타글루칸은 0.37~0.81% 로품종에상관없이귀리분말의 mesh가증가할수록함량이높아지는경향을나타내었다. 아울러수용성베타글루칸함량은 2.48~3.65% 로총베타글루칸의대부분 (76.99~90.%) 을차지하는것을알수있었다. 이러한결과는겉귀리의총베타글루칸함량이 2.2~4.2% 이며, 이중약 % 가수용성베타글루칸으로수용성이차지하는비중이높다는 Aman과 Graham(3) 의결과와도일치하였다. 한편베타글루칸은입도가큰비전분다당류로동일한제분조건에서는입자가큰구간에서높은함량을나타내므로이러한특성을이용하여베타글루칸함량이높은기능성귀리분말의제조가가능할것으로생각된다. 총전분및아밀로오즈함량귀리의분쇄크기에따른총전분과아밀로오즈의함량을측정한결과는 Table 3과같다. 총전분은겉귀리 (63.64~ 69.82%) 가쌀귀리 (52.45~63.71%) 보다높게나타났으며이는귀리의총전분함량이 59.8~61.5% 함유되어있다는 Tian 등 (33) 의연구결과와유사하였다. 또한, 겉귀리의총 Table 3. Contents of total starch and amylose of oat flours in different particle sizes Hulled oat Naked oat Total starch (%, dry basis) 69.82±0.82 a 67.63±0.58 ab 65.39±1.12 bc 63.64±1.02 c 63.71±1.42 a 58.28±0.41 b 52.45±2.01 c 54.43±1.09 c Amylose (%, dry basis) 7.54±0.07 d 8.51±0.33 c 12.34±0.09 b 12.92±0.23 a 5.47±0.20 b 7.00±.019 a 7.94±0.72 a 7.67±0.00 a Values with the different letters (a-d) within a column differ significantly (P<0.05). 전분함량은 mesh(69.82%)> mesh(67.63%)> mesh(65.39%)> mesh(63.64%) 순으로나타났으며, 쌀귀리의경우 mesh(54.43%) 를제외하고 mesh (63.71%)> mesh(58.28%)> mesh(52.45%) 순으로입자크기가작을수록유의적으로낮아졌다. 이는귀리의총전분은입자크기가작을수록증가하였다 (29) 는보고와는상반된결과로귀리의품종및식이섬유와베타글루칸의함유량에따른결과차이로생각된다. 한편아밀로오즈는전분의호화, 노화, 소화율특성등에영향을미치는성분으로함유량에따라특성의차이를나타낸다 (3). 겉귀리와쌀귀리의아밀로오즈함량은총전분과는상반된음의상관관계로귀리분말의입자크기가클수록낮아지는경향을나타내었다. 또한, 아밀로오즈의함량은겉귀리 (7.54~12.92%) 가쌀귀리 (5.47~7.94%) 보다전반적으로높은수치를나타내었으며입자크기가작을수록함량이증가하였다 (29) 는보고와일치하였다. 하지만귀리의아밀로오즈함량이 21.3% 였다는결과 (34) 와는달리상대적으로낮은값을나타내었으며이는귀리의품종및수확시기에따른함량차이로생각된다. 유리아미노산함량입자크기에따른겉귀리와쌀귀리분말의유리아미노산의함량은 17가지의아미노산표준물질 ( 필수아미노산 9가지및비필수아미노산 8가지 ) 을이용하여분석하였으며그결과는 Table 4와같다. 귀리의유리아미노산함량은귀리의종류및입도에관계없이입자크기가클수록높은경향을보였다. 즉겉귀리의경우 mesh(1,933.7±192.0 μg/g)> mesh(1,927.6±125.5 μg/g)> mesh(1,888.2±134.6 μg/g)> mesh(999.9±62.3 μg/g) 순으로나타났으며, 특히 mesh에서함량이현저하게감소하는것을확인할수있었다. 또한, 쌀귀리는 mesh(2,559.4±391.4 μg/ g)> mesh(1,820.5±167.1 μg/g)> mesh(1,457.1± μg/g)> mesh(1,270.4±155.5 μg/g) 순으로겉귀리에비해 mesh와 mesh는특이적으로약 1.3배정도높게나타났다. 한편두가지귀리모두필수아미노산

5 겉귀리및쌀귀리분말의입자크기별영양성분및이화학적특성 1297

6 1298 이유진 김진숙 김경미 최송이 김기창 의함량이총유리아미노산의절반이상 (628.4~1,633.4 μg/ g) 을차지하였으며입자가작을수록필수아미노산이차지하는비율은유의적으로감소하였다. 이는입도가작을수록조단백질및아미노산함량이감소한다 (29) 는결과와유사하였으며귀리부위별아미노산함량은강층이배유와분말보다높다는결과를뒷받침해준다 (1). 아울러겉귀리와쌀귀리의아미노산조성별함량을살펴보면 serine, glycine, threonine, lysine, isoleucine, leucine 등은입도가작아질수록함량이감소하였으며겉귀리에서는필수아미노산인 histidine, arginine과비필수아미노산인 glutamic acid가 mesh를제외하고입자가작아짐에따라증가하는경향을나타내었다. 또한, aspartic acid와 glutamic acid는겉귀리 mesh에서는함량이많이감소하여각각미량, 94.8 μg/g을나타냈지만쌀귀리는 83.8 μg/g, μg/g으로많이증가하는것을확인할수있었다. 또한, 17가지의표준물질중유일하게 cystine은겉귀리, 쌀귀리모두에서검출되지않았다. 따라서각각의아미노산조성에따라함량의감소및증가경향이모두차이가있음을알수있었으며이는 Yu(23) 의연구결과와도일치하였다. 지방산함량귀리의종류및입자크기에따른지방산의함량을비교한결과는 Table 5와같다. 겉귀리와쌀귀리두종류모두포화지방산인 palmitate(c16:0), stearate(c18:0) 가검출되었으며불포화지방산은 oleic acid(c18:1), linoleate(c18:2) 및 linolenate(c18:3) 가검출되었다. 아울러겉귀리와쌀귀리간의지방산조성및함량에따른유의적인차이는보이지않았으며이러한결과는 Yu(23) 의보고와도일치하였다. 한편겉귀리의경우 palmitate는 4.81~5.58%, stearate는 0.50~0.62% 로소량존재함을확인하였으며, oleic acid는 22.75~26.%, linoleate는 38.14~44.11%, linolenate는 0.57~0.72% 함유되어있음을알수있었다. 반면쌀귀리의경우 palmitate 4.92~6.06%, stearate 0.38~0.70%, oleic acid 22.33~29.75% 및 linoleate 36.43~46.73%, linolenate 0.31~0.75% 로전반적으로쌀귀리의함량이높은것 을확인할수있었다. 겉귀리와쌀귀리의불포화지방산은입자크기와관계없이전체지방산조성의약 90% 이상이며귀리의주요지방산은 palmitate, oleic acid, linoleate 등으로다른곡류에비해불포화지방산의조성이높은것으로나타났다 (2). 호화특성분석입자크기에따른겉귀리와쌀귀리분말의호화특성을분석하였으며, 그결과는 Table 6과같이최고점도, 최저점도, 최종점도, 강하점도, 치반점도, peak time 및호화온도로표시하였다. 귀리입도별호화특성에따른뚜렷한경향은보이지않았으나최고점도, 최저점도및강하점도는겉귀리 (215.08, , RVA), 쌀귀리 (210.00, , RVA) 두종류모두 mesh에서높게나타나는것을확인하였다. 아울러강하점도는가공중의안정도를확인하는지표로써입자크기가작을수록값이증가하는경향을나타내며 (35) 입도가작은시료의최고점도가높다 (36) 는연구결과와일치하였다. 한편최종점도와치반점도는입자크기가큰귀리분말이상대적으로높은수치를나타났으며겉귀리는 mesh(424.44, RVA) 에서, 쌀귀리는 mesh(338.45, RVA) 에서각각높게나타났다. 치반점도는노화와밀접한관계가있으며입자크기가작을수록높다는연구결과 (35) 와다소차이가있었다. 최고점도에이르는 peak time의경우겉귀리와쌀귀리모두 mesh(6.29, 6.11 min)> mesh(6.16, 6.02 min)> mesh(6.07, 5.85 min)> mesh(5.82, 5.62 min) 순으로귀리의입자가클수록높은경향을나타냈다. 아울러호화개시온도는귀리의입자크기가작을수록감소하는경향을보였으며겉귀리 (64.85 C) 와쌀귀리 (63.20 C) 모두 mesh에서가장낮게나타났으며, 이는입자크기가작아짐에따라낮아진다는 Kum과 Lee(37) 의연구결과와일치하였다. 따라서입도에따른영양성분의조성변화가귀리의물리적특성과가공적성에도영향을주는것을확인할수있었다. Table 5. Contents of fatty acid of oat flours in different particle sizes Hulled oat Naked oat Palmitate (C16:0) 4.81± ± ± ± ± ± ± ±0.90 Stearate (C18:0) 0.50± ± ± ± ± ± ± ±0.53 Fatty acid content (%, dry basis) Cis-9-Oleic acid (C18:1) 22.75± ± ± ± ± ± ± ±7.62 Linoleate (C18:2) 38.14± ± ± ± ± ± ± ±7.70 Results are not significantly different at P<0.05 significance level by Duncan's multiple range test. Linolenate (C18:3) 0.57± ± ± ± ± ± ± ±0.54

7 겉귀리및쌀귀리분말의입자크기별영양성분및이화학적특성 1299 Table 6. Pasting properties of oat flours in different particle sizes Hulled oat Naked oat Peak viscosity ±2.38 c ±5.09 ab ±12.05 b ±9.56 a ±3.01 c 1.75±6.04 b ±5.75 c ±8.37 a Trough viscosity ±0.95 c ±6.47 b ±4.20 c ±9.01 a.39±1.70 c ±5.68 b 98.72±5.08 c ±6.35 a Breakdown viscosity 49.44±2.09 b 67.06±1.79 a 74.70±10.42 a 68.86±2.96 a 51.22±1.44 d 68.86±1.38 b 62.56±2.53 c 73.44±2.05 a Final viscosity ±16.33 b ±3.54 a ±10.51 b ±12.51 b ±2.86 a ±13.32 a ±11.66 b ±8.31 b Values with the different letters (a-c) within a column differ significantly (P<0.05). Setback viscosity ±17.15 b ±3.29 a ±6.51 b ±4.59 b ±1.42 a ±7.65 a ±6.79 b ±1.97 c Peak time (min) 5.82±0.08 b 6.07±0.14 a 6.16±0.20 a 6.29±0.03 a 5.62±0.04 c 5.85±0.04 b 6.02±0.04 a 6.11±0.03 a Pasting temperature ( C) 83.72±6. a 73.10±9.61 ab 68.85±4.72 b 64.85±2.06 b 87.48±0.88 a 67.55±2.86 bc 72.82±10.03 b 63.20±0.52 c Table 7. The amount of starch nutritional fractions (RDS, SDS, RS) and expected glycemic index (egi) of oat flours in different particle sizes Hulled oat Naked oat Starch fraction 1) (%) RDS SDS RS 32.19±2.72 ab 28.15±0.53 ab 23.41±8.08 b 39.±2.14 a 25.58±1.02 c 32.37±2.81 b 42.71±2.18 a 32.42±2.61 b 26.20±1.68 c 32.09±2.04 b 44.45±1.81 a 42.37±0.65 a 37.52±6.14 NS3) 44.18± ± ±5.88 Values with the different letters (a-c) within a column differ significantly (P<0.05). 1) RDS: rapidly digestible starch, SDS: slowly digestible starch, RS: resistant starch. 2) egi: expected glycemic index. 3) NS: not significant ±1.70 a 39.48±3.33 ab 33.88±5.90 ab 27.98±4.75 b 36.29±7.82 a 23.73±3.87 ab 13.34±1.36 b 18.34±6.54 b egi 2) 76.57±1.17 b.61±1.48 ab 84.01±3.36 a 85.53±2.66 a.±4.15 b 89.61±2.44 ab 95.73±3.65 a 92.20±2.94 a In vitro 소화율귀리전분의 in vitro 소화율과 in vitro egi를측정한결과는 Table 7과같다. 전분소화율은겉귀리가쌀귀리에비해 RDS(25.58~42.71%) 와 SDS(23.41~39.%) 의함량이낮게나타났지만 RS(27.98~42.23%) 의함량은비교적높게나타났으며품종및입도크기에따른일정한경향성은보이지않았다. RS는인체내느리게대사되어포만감을증가시키며혈당및인슐린반응을감소시켜당뇨병의위험을낮추는전분으로 (38) 다른곡류에비해상대적으로매우높은수치 ( 겉귀리 27.98~42.23%, 쌀귀리 13.34~36.29%) 를나타내었다. 이는귀리의식이섬유는 RDS를감소시키며 RS 를증가시켰다 (28) 는연구결과로미루어보았을때귀리의식이섬유및지방의함량이다른곡류에비해많은것에기인하는것으로생각된다. 한편혈당지수는식품의분쇄나제분등의가공방법에따라영향을받으며입자의크기가줄어들면물에쉽게흡수되고소화효소의접근이용이하여혈당지수가높아진다 (38). 또한, 전분내아밀로오스의비율이높을수록낮아진다 (39) 는보고와는다른경향을나타내었는데이는입자가클수록전분및식이섬유의함량이높다 (29) 는연구결과에더많은영향을받은것으로생각된다. 식빵 (egi=) 을기준으로 egi를분석한결과겉귀리 (76.57~85.53) 가쌀귀리 (.~95.73) 보다전반적으로값이낮았으며입자가클수록낮아지는경향을나타내었다. 또한, 겉귀리및쌀귀리모두 mesh에서각각 76.57,.으로가장낮게나타났다. 전분의소화율과소화속도는전분의구조나가공방법에따라다양하게나타날수있으며전분의종류, 아밀로오스와아밀로펙틴의비율및입자의크기등에영향을받는다 (). 따라서향후입도별귀리의전분결정및분자구조에대한추가적인연구가필요하며이를통해소화율이낮은기능성귀리제품을개발하는데도움이될것으로생각된다. 요약국내에서육종된겉귀리 ( 조한 ) 와쌀귀리 ( 조양 ) 를,,, mesh로분쇄하여얻은귀리분말의입자크기별영양성분및이화학적특성을조사하였다. 총베타글루칸의함량은겉귀리의경우 mesh(4.23%), 쌀귀리는 mesh (4.26%) 에서가장높게나타났으며, 수용성베타글루칸은총베타글루칸의 76.99~90.% 로대부분차지하였다. 총

8 1300 이유진 김진숙 김경미 최송이 김기창 전분은겉귀리 (63.64~69.82%) 가쌀귀리 (52.45~63.71%) 에비해함량이높았으며입자가작을수록감소하는경향을나타냈지만아밀로오즈는총전분과음의상관관계를나타내었다. 한편유리아미노산은조성에따라감소및증가패턴의차이를보였으나겉귀리와쌀귀리모두입도가클수록유의적으로높게나타났다. 아울러지방산은입도별유의적인차이는보이지않았으며겉귀리에비해쌀귀리의함량이높고불포화지방산 (oleic acid, linoleate) 이약 90% 이상함유되어있음을확인하였다. 호화특성인최고점도, 최저점도및강하점도는겉귀리와쌀귀리모두 mesh에서높게나타났으며최종점도와치반점도는입자크기가큰귀리분말이상대적으로높았으며호화개시온도는귀리의입자크기가작을수록감소하는경향을보였다. 한편전분소화율의경우입자가큰귀리분말의 RS 함량이높게나타났으며 egi는겉귀리 (76.57~85.53) 가쌀귀리 (.~95.73) 보다전반적으로낮았고입자가클수록감소하는경향을나타내었다. 이러한결과를종합해보면귀리의종류및입자크기에따른특성이최종가공제품에영향을미칠수있으므로용도및가공적성에적합한귀리분말을선택하는것이중요할것으로생각된다. 감사의글 본논문은농촌진흥청연구사업 ( 과제번호 : PJ ) 지원에의해이루어진것으로이에감사드립니다. REFERENCES 1. Hahn JD, Chung TK, Baker DH Nutritive value of oat flour and oat bran. J Anim Sci 68: Leonova S, Shelenga T, Hamberg M, Konarev AV, Loskutov I, Carlsson AS Analysis of oil composition in cultivars and wild species of oat (Avena sp.). J Agric Food Chem 56: Aman P, Graham H Analysis of total and insoluble mixed-linked (1-3),(1-4)-D-β-glucans in barley and oats. J Agric Food Chem 35: Thies F, Masson LF, Boffetta P, Kris-Etherton P Oats and CVD risk markers: a systematic literature review. Br J Nutr 112: S19-S Lee YT Physicochemical characteristics and physiological functions of β-glucans in barley and oats. Korean J Crop Sci 41(S1): Park HJ, Kim YB, Kang TS, Jung IS, Kim KY, Jeong HS Immunomodulatory activities of oat bran extracts with different extraction conditions. Korean J Food Sci Technol 37: Peterson DM, Quresh AA Genotype and environment effects on tocols of barley and oats. Cereal Chem 70: Peterson DM, Hahn MJ, Emmons CL Oat avenanthramides exhibit antioxidant activities in vitro. Food Chem 79: Gutkoski LC, EI-Dash AA Effects of extrusion variable on functional and nutritional properties of extruded oat products. J Food Sci Nutr 4: Welch RW The oat crop. production and utilization. Economic Botany 51: Park BG, Lee HJ, Lee KH Adaptation and quality of naked oat (Avena nuda L.) cultivars in Korea. Korean J Breed 27: Korea Customs Service Trend of major grains the first half of income by Seoul, Korea. 13. Han OK, Park TI, Park HH, Song TH, Kim KJ, Park NG, Ju JI A new high-yielding winter oat cultivar for whole crop forage, Dahan. J Korean Soc Grassl Forage Sci 34: Park HH, Heo HY, Park KH, Park TI, Seo JH, Cheong YK, Choi JS, Kim JG, Kwon YU, Ju JI, Rye IM, Hong YG, Jung KY, Han OK A new early-heading and highyielding forage winter oat cultivar, Chohan. Korean J Breed Sci 39: Han OK, Park HH, Park TI, Seo JH, Park KH, Kim JG, Heo HY, Hong YG, Kim DH A new early-heading and high-yielding naked oat cultivar for human consumption, Choyang. Korean J Breed Sci : Kim JG, Park HS, Lee SH, Jung JS, Lee KW, H Jong Ko Evaluation of productivity and silage quality for domestically developed forage crops in Korea. J Korean Soc Grassl Forage Sci 35: Han OK, Park TI, Park HH, Song TH, Hwang JJ, Baek SB, Kim DW, Kwon YU Effect of seeding dates on yield and quality of various oat cultivars for year-around forage production. J Kor Grassl Forage Sci 32: Park HJ, Kang TS, Lee HB, Kim KY, Jang KI, Noh YH, Jeong HS Purification of oat β-glucan by α-amlyase treatment and characterization of its physicochemical properties. Korean J Food Sci Technol 37: Kang TS, Jeong HS, Park HJ, Lee MY, Kong YJ, Jung IS Biological activities or oat soluble β-glucans. Korean J Food Preserv 10: Lee YT β-glucans in barley and oats and their changes in solubility by processing. J Korean Soc Agric Chem Biotechnol 39: Jeong HS, Kang TS, Jung IS, Park HJ, Min YK β- Glucan contents with different particle size and varieties of barley and oats. Korean J Food Sci Technol 35: Oh SH Development of traditional Doenjang added with fermented oat and its functionality. MS Thesis. Jeonbuk University, Jeonju, Korea. 23. Yu SH Effect of particle size of naked oat on physicochemical and baking properties. MS Thesis. Jeonbuk University, Jeonju, Korea. 24. Lee C Changes in the microbiological characteristics of oat extract by lactic-bacterial fermentation. J Korean Soc Food Sci Nutr 38: Kim BY, Choi HS, Lyu ES Quality characteristics of cookies prepared with oat and barley powder. Korean J Food Cook Sci 30: Oh NG Research on cultivation and processing technologies in winter naked oats. PhD Dissertation. Jeonbuk University, Jeonju, Korea. 27. Dikeman CL, Fahey GC Viscosity as related to dietary fiber: a review. Crit Rev Food Sci Nutr 46: Asp NG, Björck I Resistant starch. Trends Food Sci Technol 3: Lee HI, Lee HG, Bae IY Impact of dietary fibers from various source in wheat flour gel model: Aspect of suitability of processing and in vitro starch digestibility. Food

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학술원논문집 ( 자연과학편 ) 제 50 집 2 호 (2011) 콩의식품적의의및생산수급과식용콩의자급향상 李弘䄷 * 李英豪李錫河 * * Significance of Soybean as Food and Strategies for Self Suffici

학술원논문집 ( 자연과학편 ) 제 50 집 2 호 (2011) 97-137 콩의식품적의의및생산수급과식용콩의자급향상 李弘䄷 * 李英豪 ** 李錫河 *** * Significance of Soybean as Food and Strategies for Self Sufficiency Improvement Hong Suk Lee*, Yeong-Ho Lee**, and