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KOREAN J. FOOD COOKERY SCI. Vol. 29, No. 5 October, 2013 ISSN 2287-1780(Print) ISSN 2287-1772(Online) http://dx.doi.org/10.9724/kfcs.2013.29.5.469 타피오카전분의첨가가쌀쿠키의품질특성에미치는영향 이준경 오성훈 1 임재각 한국산업기술대학교생명화학공학과 신안산대학교식품생명과학과 1 Effects of Tapioca Starches on Quality Characteristics of Rice Cookies Joon-Kyoung Lee, Sung Hoon Oh 1 and Jae Kag Lim Department of Chemical Engineering & Biotechnology, Korea Polytechnic University 1 Department of Biotechnology & Food Science, ShinAnsan University Abstract The effects of tapioca starch (TS) and tapioca modified starch (TMS) as additives on the quality characteristics of rice cookies were investigated in this study. The amounts of TS and TMS replaced were 5, 10 and 15%(w/w) based on 100 g of rice flour. At the result of rapid viscosity analyser (RVA) properties of rice flour added with starches, peak, trough, and final viscosity of rice flour added with TMS decreased significantly(p<0.05). Hardness of dough and cookies as measured by Texture analyzer (TA) significantly decreased upon addition of TMS, and hardness of cookies significantly decreased upon addition of TS, hardness of cookies TMS lower than TS. L value of dough and cookies increased upon addition of TMS, whereas a value decreased upon addition of TMS. Spreadability of cookies increased upon addition of TMS, 10% TMS is the highest. Bulk density of dough decreased upon addition of TMS, bulk density of cookies decreased upon addition of TS and TMS, and bulk density of TMS cookie lower than TS cookie. In sensory evaluation, 10% TS added rice cookies showed the highest score in overall acceptability, hardness, brittleness, color, softness, taste and flavor, and 15% TS added rice cookies showed the highest score in appearance. And 15% TMS added rice cookies showed the highest score in overall acceptability, taste, brittleness, flavor, and 10% TMS added rice cookies showed the highest score in hardness, flavor, taste and color. It is indicated that the quality characteristics and sensory characteristics of the rice cookie can be improved by adding TS and TMS Key word : rice cookie, tapioca starch (TS), tapioca modified starch (TMS), quality characteristics I. 서론 1) 쌀 (Oryza sativa L.) 은동양여러나라에서오랜기간주식 ( 主食 ) 으로섭취되어온작물이다. 급속한경제발달로국민의식생활문화가변화하면서쌀의소비가점차줄어들고있으며, Corresponding author : Jae-Kag Lim, Department of Chemical Engineering & Biotechnology, Korea Polytechnic University, JeongWang-dong, Siheung-si, Kyungggi-do, 429-793, Korea Tel : +82-31-8041-0616 Fax : +82-31-8041-1834 E-mail : jklim@kpu.ac.kr 점차면류, 빵류, 과자류와같은밀가공제품이쌀가루를혼합하거나쌀가루위주의제품으로새로운시장을형성하고있으나, 여전히밀가루를쌀가루로대체하였을때제품에서나타나는식감및품질의문제점은해결되지못하고있다 (Shin MS 2010). 쌀에는밀가루반죽시형성되는점탄성단백질인글루텐을형성하는글리아딘과글루테닌이존재하기않아쌀가루반죽은탄력성과점착성이부족하다. 따라서반죽의취급이나제품의형성이어렵다. 또한제품에서는부피감소및경도증가뿐만아니라관능적인식감또한밀가루제품에비해현저히낮아밀가루를대체한제품을개발하는데큰어려움이있다. 쌀가루를이용한제과제빵제품, 특히쌀빵에서나타나는

470 이준경 오성훈 임재각 품질저하를해결하기위한연구가시도되어왔다. 제분법에따른쌀가루를이용한연구도보고되었는데, 습식쌀가루가쌀빵의부피와질감을개선한다는연구 (Lee MH와 Lee YT 2006) 가있다. 습식쌀가루의개선효과에관련된연구로는산처리및압출팽화시킨쌀가루로제조한쌀빵의경우조직감및빵표면의색이개선되어밀가루빵과유사한품질을갖는것으로확인되었다 (Maria TPSC 등 2009). 또한 Glucose oxidase나 α-amylase와같은효소와 HPMC(hydroxypropyl methylcellulose), guar gum, tara gum 등의검류를복합첨가한쌀빵의경우부피가증가하고관능적기호도를높이는효과뿐만아니라쌀빵의노화를지연하는효과 (Hardeep SG와 Cristina MR 2004, Hardeep SG 등 2004, Hema PS 등 2004, Kim KE와 Lee YT 2009) 도있는것으로보고되었다. 밤가루와쌀가루혼합물로제조한쌀빵의경우밤가루와쌀가루의혼합비율이 30 : 70일때가장적절한것으로보고하였고 (Ilkem D 등 2010), 탈피시킨메밀가루의첨가가쌀빵의경도를증가시키지만탈피하지않은메밀가루보다관능적기호도가높은것으로나타났으며 (Aleksandra T 등 2010), 검류인 PGA(propylene glycol alginate) 와함께메밀가루를첨가한경우는쌀빵의부피를증가시키고빵껍질의견고성을감소시키는것으로보고되었다 (Donatella P 등2011). 이처럼 gluten-free 빵에대한연구는활발히진행되어왔으며 gluten-free 쿠키에대한관심도증가하고있다. 쌀가루를기본으로한쌀쿠키에관련된연구도이루어지고있다. 옥수수유와변성전분및검물질을혼합하여만든지방대체제의첨가에의해쿠키반죽의경도는반죽의휴지시간에따라증가하고관능적기호도또한높은것으로보고하였다 (Kim MY 2007). 또한아밀로오스함량이높을수록쿠키의경도는낮고저장기간에따른경도변화도거의없다고보고하였다 (Kwon YR 등 2011). 생리활성이나기능성을갖는물질을첨가한쿠키의제조적성을확인한연구로, 기능성쌀을이용한쌀쿠키의경우기능성쌀첨가량이증가함에따라경도변화는없지만관능적기호도가증가하는것으로나타났으며 (Kim HY 등 2002), 깨또는 octenyl-succinated 전분의첨가 (Jung YJ 등 2007, Han JA 2009) 는쌀쿠키의경도를낮추었고연자나복령의첨가 (Kim SM 2011) 는경도가증가했지만관능적기호도는높았다. 지금까지쌀가루로제조한쿠키는여러연구에서시도되었으나반죽및쌀쿠키물성에대한연구, 또는전분과같은첨가제를이용하여쌀쿠키의가공적성을높이려는연구는부족한실정이다. 타피오카전분은카사바 (Manihot esculenta Crantz) 의뿌리로부터추출한것으로다른전분에비해탄수화물함량이높고단백질함량이낮다. 또한강수량이적거나척박한토양에서도생산성이높으면서생산비는낮아점점수요가증가한추세이다 (Kim 등 2007, Mishra and Rai 2006). 타피오카전분은점성이높고무색투명하고쫄깃한식감을가지며, 소화ㆍ흡수가잘되는전분으로식품산업에널리쓰이고있다 (Song과 Park 2000, Ahn GJ 2005). 타피오카전분을첨가한절편의조직감과기호성을평가한연구에서, 쌀가루로만만든처리군보다타 피오카전분 5% 첨가군이조직감과기호성이더좋게나타났고 (Ahn, 2005), 쌀식빵에관한연구에서는대조군에비해타피오카등의전분첨가군이발효팽창력에있어안정적인형태를보이며제품의구조를강하게하는것이라는연구보고가있었다 (Yoon YK 2011). 최근에는국내에서도타피오카전분을이용하여조직감을향상시킨베이커리제품이인기를끌면서주목받고, 선호되고있어, 타피오카전분을참가하여탄력성이좋은제품에대한소비자의요구도가증가하고있는것으로사료된다. 또한식품의조직감을향상시키기위한목적으로최근변성전분의개발이이루어지고있다 (Choi HM와 Yoo BS 2007, Shin MS. 2001). 타피오카히드록시프로필전분은반죽의쫄깃함과부드러움을조절하기위한것으로식품산업에이용되고있는추세이다. 따라서본연구에서는타피오카전분의첨가가쌀반죽및쌀쿠키의질감특성과관능특성에미치는영향에대하여알아보고자하였다. 1. 재료 II. 재료및방법 쌀쿠키제조에사용된쌀가루는 ( 주 ) 태평양물산 (Panpacific Co., Ltd, Ansan, Korea) 에서습식제분법으로생산한멥쌀가루를구입하여실험에사용하였다. 타피오카전분 (; TS) 과알칼리촉매하에서 propylene oxide 를첨가하여 glucose 단위 2 번탄소위치에하이드록시프로필기를치환시켜제조한타피오카변성전분 (Tapioca modified starch; TMS) 은 ( 주 ) 삼양제넥스 (Samyang Genex Co., Seoul, Korea) 에서구입하여실험에사용하였으며, 쌀가루중량의 5, 10 및 15% 를쌀가루와대체하여혼합하였다. 쌀쿠키제조에사용된쇼트닝은 ( 주 ) 오뚜기 (Ottogi Co., Ltd., Seoul, Korea), 백설탕은 ( 주 )CJ(CJ Co., Ltd., Seoul, Korea), 계란은이마트에서구입하여사용하였다. 2. 일반성분 쌀가루의일반성분은 AOAC 법 (AOAC 1990) 에의하여측정하였다. 쌀가루의수분함량은 105 에서상압가열건조법, 조지방은 Soxhlet 추출법, 조단백질은 Kieldahl 법, 조회분은직접회화법으로측정하였다. 3. RVA 의호화특성 쌀가루중량의 5, 10 및 15% 를타피오카생전분및변성전분으로대체하여혼합한쌀가루의호화특성은 Rapid visco analyser(rva Super 4, Newport scientific Inc., Warriewood, Australia) 를이용하여측정하였으며, Thermal cycle windows software 로결과를분석하였다 (AACC 2000). 쌀가루 3 g 을증류수 25 ml 가든원통형알루미늄용기에잘분산시킨후용기를기기에장착하여측정하였다. 측정조건은 50 에서 1 분 한국식품조리과학회지제 29 권제 5 호 (2013)

타피오카전분의첨가가쌀쿠키의품질특성에미치는영향 471 간유지한후 11.83 /min 의속도로 95 까지상승시켜 2 분 30 초동안유지시키고, 11.83 /min 의속도로 50 까지냉각시켜약 1 분간유지시켰으며, 얻어진결과를 Rapid visco unit(rvu) 으로나타내었다. 4. 쌀쿠키의제조 쌀쿠키배합비와제조과정은예비실험을통하여확립한조건을각각 Table 1 과 Fig. 1 에나타내었으며, 모든원료는쌀가루중량대비비율로나타내었다. 실험에사용한쌀가루는 40 mesh 의 sieve 를통과시켰다. 쌀쿠키제조에는 1~10 단까지속도를조절할수있는 Mixer(5KPM50, Kitchen Aid Co., Ltd., Ohaio, USA) 를사용하였다. Mixing bowl 에쇼트닝과설탕을넣고저속 1 분, 중속 1 분, 고속 1 분간혼합하였다. 전란액을첨가한후중속 1 분, 고속 2 분간혼합하여크림화하였다. 소금을용해시킨배합수를첨가한후중속에서 2 분간혼합하여크림을완성하였다. 쌀가루와쌀가루중량의 5, 10 및 15% 를전분으로대체하여섞은후체에친것을크림과함께저속 1 분간혼합하여쿠키반죽을완성하였다. 완성된반죽을랩으로싼후상온에서 30 분동안휴지시켜반죽의품질특성을측정하였다. 10 mm의두께로반죽을편후원통형쿠키커터 (Φ36 mm ) 로반죽을성형하여윗불 190 와아랫불 150 의오븐 (HYMPO-104, Hanyoung Co. Hanam. Korea) 에서 15 분간구웠다. 구워진쌀쿠키는 30 분간상온에서방냉한후쿠키의품질특성을측정하였다. Weighting ingredients Mixing (6 min) Mixing (2 min, medium speed) Mixing (1 min, low speed) Adding shortening, sugar, whole egg liquids in mixing bowl Adding water with 1% salt Adding rice flour and starches Table 1. Formula for rice cookie Control (%) (%) Tapioca modified starch (%) Ingredients 1) 0 5 10 15 5 10 15 Wet-milled rice flour 100 95 90 85 95 90 85 0 5 10 15 0 0 0 Tapioca modified starch 0 0 0 0 5 10 15 Shortening 63.3 63.3 63.3 63.3 63.3 63.3 63.3 Sugar 15 15 15 15 15 15 15 Whole egg liquids 26.7 26.7 26.7 26.7 26.7 26.7 26.7 Salt 1 1 1 1 1 1 1 1) Ingredients were added on the basis of wet-milld rice flour 100 g. 5. 색도 타피오카전분을첨가한반죽및쿠키의색도는색차계 (Color reader CR-10, Konica Minolta Sensing Inc., Osaka, Japan) 를사용하여반죽및쿠키표면의 L (lightness) 값, a (redness) 값, b (yellowness) 값을측정하여그결과값을나타내었다. 6. 쿠키의퍼짐성 쿠키의퍼짐성지수는 AACC method 10-50D 의방법 (AACC 2000) 을사용하여측정하였다. 쿠키의평균직경은쿠키 6 개를나란히수평으로정렬한후전체길이를측정하고, 쿠키를 90 로회전시킨후같은방법으로길이를측정한다음각각을 6 으로나누어쿠키한개에대한평균직경을구하였다. 쿠키의두께는같은쿠키 6 개를수직으로쌓은후그높이를측정하고각각 6 으로나누어다시쿠키의순서를다르게쌓아높이를측정한다음쿠키한개에대한평균두께를구하였다. 쿠키의퍼짐성지수는쿠키의두께 (mm) 와직경 (mm) 의비로구하였으며, 3 회이상반복하여측정하였다. 계산식은아래의식을이용하였다. Dough formation Resting (30 min at room temp.) Sheeting and shaping (thickness 10 mm, diameter 36 mm) Baking (14 min at 190, 150 ) Cooling (30 min, at room temp.) Rice cookie Fig. 1. Process flow diagram of cookie made of rice flour Spread ratio = Average width of 6 cookies(mm)/average thickness of 6 cookies(mm) 7. 밀도 반죽및쌀쿠키의밀도 (bulk density) 는무게와부피의비로나타내었다. 부피측정은종자치환법 (Pyler EJ 1979) 에의하여측정하였다. 8. 경도 타피오카전분을첨가한반죽및쿠키의경도 (hardness) 는 Texture Analyser(TA.XT Express, Stable Micro Systems Ltd., Godalming, UK) 를사용하여측정하였으며한시료당 10 회반복실시하였다. 반죽 35 g 을원통형용기 (Φ55 75 mm 에 Korean J. Food Cookery Sci. Vol. 29, No. 5(2013)

472 이준경 오성훈 임재각 넣고반죽표면을평평하게눌러준후직경 10 mm 의 Cylinder plunger 를사용하여측정하였으며, 10 mm 두께의반죽을원통형쿠키커터 (Φ36 mm) 로성형하여구운쌀쿠키의경도는직경 5 mm 의 Cylinder plunger 를사용하여측정하였으며측정조건은 Table 2 와같다. Table 2. The operating conditions of texture analyser for dough and rice cookie Conditions Parameters Dough Cookie Plunger type Φ10 mm Cylinder Φ5 mm Cylinder Deformation 50% Test mode Cycle test Load cell 5 kg Pre-test speed 2.0 mm/s Test speed 0.5 mm/s Post-test speed 5.0 mm/s 9. 관능평가 타피오카전분을첨가하여제조한쿠키의관능검사는훈련된대학원생 (20~38 세 ) 패널 12 명을대상으로실시하였다. 전분첨가쿠키와무첨가쿠키의관능적특성을각각살펴보았고평가항목은각각외관 (Appearance), 색 (Color), 맛 (Taste), 향 (Flavor), 단단한정도 (Hardness), 바삭거림정도 (Brittleness), 촉촉한정도 (Moistness), 부드러운정도 (Softness), 목넘김이거친정도 (Sandiness) 및전반적인기호도 (Overall acceptability) 에대하여 9 점척도법 (9 점 : 매우좋다 ~5 점 : 좋지도싫지도않다 ~1 점 : 매우싫다 ) 으로 3 회반복하여평가하였다. 10. 통계처리 모든실험의결과값은최소 3 반복을실시한평균과표준편차로나타내었다. 실험에대한유의차검정은통계프로그램인 SAS(Statistical analytical system version 9.1, SAS Institute Inc. Cary, NC 27513, USA) 를이용하여평균값을분산분석한후 α=0.05 수준에서 Duncan's multiple range test 에따라분석하였다. 1. 쌀가루의일반성분 III. 결과및고찰 쌀쿠키제조에사용한쌀가루의일반성분측정결과는 Table 3 과같다. 수분함량은 14.05%, 조단백질함량은 6.80%, 조회분함량은 0.61%, 조지방함량은 0.34% 로나타났다. Table 3. Compositional analysis of rice flour Compositional analysis (%) Moisture content Crude protein Crude ash Crude lipid Rice flour 14.05±0.08 1) 6.80±0.01 0.61±0.04 0.34±0.01 1) Values are Mean±S.D.. 2. RVA 에의한호화특성변화 타피오카생전분과타피오카변성전분을쌀가루중량대비각각 5, 10 및 15% 씩대체하여혼합한전분류가쌀가루의호화특성에미치는변화를 Table 4 에나타내었다. RVA 로측정한각시료의시간에따른점도변화에서호화개시온도, peak time, trough, final, breakdown, setback 점도등의호화특성을나타내었으며, 호화개시온도는대조군쌀가루현탁액 69.28, 타피오카생전분을첨가한쌀가루현탁액 68.55~69.03, 타피오카변성전분을첨가한쌀가루현탁액이 67.12~68.08 로나타나타피오카변성전분첨가로쌀가루현탁액의호화개시온도가낮아졌다. 최고점도에이르는 peak time 이타피오카생전분첨가로감소하여타피오카전분첨가쌀가루현탁액의호화시간이단축되는것을알수있다. Peak, trough 및 final viscosity 의점도변화는전체적으로타피오카변성전분첨가쌀가루현탁액이타피오카생전분첨가쌀가루현탁액보다변화폭이크게나타났다. 타피오카생전분첨가쌀가루현탁액의 peak, trough 및 final viscosity 의점도변화는전분을첨가하지않은경우와큰차이가나타나지않았고, 타피오카변성전분에의한쌀가루현탁액의점도변화는전분첨가량의증가에따라유의적으로감소하였다. 타피오카변성전분은대조군에비해 15% 첨가군에서 peak viscosity 74.7 RVU, trough viscosity 49.8 RVU, final viscosity 75.6 RVU 만큼점도를감소시켜생전분보다변성전분이이들점도변화에큰영향을주는것으로나타났다. 이러한점도변화로부터나타낸 breakdown(peak-trough) 은호화중에전분의열과전단에의한저항을나타내는정도 (Kim JS 와 Shin MS 2006) 로타피오카변성전분과비교해타피오카생전분의첨가가쌀가루현탁액의 breakdown 점도를억제하는역할을하는것으로나타났다. 가공안정도를나타내는 breakdown 점도는대조군쌀가루현탁액이 79.7 RVU, 타피오카생전분첨가쌀가루현탁액은 82.1~86.1 RVU 로나타나대조군쌀가루현탁액보다높게나타났고, 타피오카변성전분첨가쌀가루현탁액은 54.9~68.2 RVU 로나타나대조군쌀가루현탁액보다낮게나타났으며, 타피오카변성전분첨가량증가에따라 breakdown 점도가감소하는경향을나타냈다. 노화의정도를나타내는 setback(final viscosity-trough) 은쌀가루현탁액을가열한후 50 로냉각시키는과정에서전분사슬의재결합에의해증가하는점도의값으로무첨가쌀가루가 150.1 RVU 로나타났고, 타피오카생전분첨가쌀가루현탁액은 132.9~144.9 RVU, 타피오카변성전분첨가쌀가루현탁액은 124.4~140.1 RVU 로대조군쌀가루현탁액보다낮게나 한국식품조리과학회지제 29 권제 5 호 (2013)

타피오카전분의첨가가쌀쿠키의품질특성에미치는영향 473 Table 4. Pasting properties of wet-milled rice flour added with starches measured by rapid visco-anaylser Viscosity (RVU) Starches Addition rate 1) Peak time Peak 1 Trough Breakdown Final Setback (min) Pasting Temp.( ) Control 268.5±18.2 a2) 188.7±21.2 a 79.7±7.0 ab 338.9±37.9 a 150.1±17.5 a 6.72±0.09 a 69.28±0.08 a 5 268.2±16.3 a 184.6±21.3 a 83.7±5.8 a 329.5±36.4 a 144.9±15.7 a 6.66±0.08 ab 69.03±0.43 a 10 269.2±14.0 a 183.1±23.8 a 86.1±10.1 a 321.2±36.8 a 138.1±13.2 a 6.57±0.07 b 68.55±0.13 ab 15 271.3±11.2 a 189.2±20.4 a 82.1±9.7 ab 322.1±31.5 a 132.9±12.0 d 6.61±0.07 b 68.57±0.10 ab 5 241.2±11.1 b 173.0±20.4 a 68.2±9.5 bc 313.1±33.0 a 140.1±12.9 a 6.74±0.05 a 67.12±0.75 d Tapioca modified starch 10 215.7±6.6 c 155.7±20.8 ab 60.0±14.3 c 286.9±32.7 ab 131.3±12.0 a 6.72±0.11 a 67.62±0.41 cd 15 193.8±2.0 d 138.9±12.7 b 54.9±10.9 c 263.3±24.3 b 124.4±12.9 a 6.69±0.09 ab 68.08±0.40 bc 1) Starches were added in 5, 10 and 15% substituted for rice flour 100 g. 2) Different superscripts in a row indicate significant differences at p<0.05 by Duncan's multiple range test 타났고, 전분첨가량증가에따라감소하는경향이나타났다. 타피오카변성전분첨가에의한 setback 점도가타피오카생전분첨가보다크게감소하는것으로나타났다. Yoo JN과 Kim YA(2001) 는쌀가루의호화특성비교연구에서싸이클로덱스트린첨가로쌀가루현탁액의 breakdown이증가되어호화를촉진하고, setback은감소되어노화를지연시킨다고보고한바있다. 또한 Oh MH 등 (2010) 의연구에서도트레할로스와효소제를함께첨가한쌀가루현탁액의 breakdown이증가되었고, setback은더욱감소하여쌀가루현탁액의호화촉진과노화억제에효과적인것으로보고하였다. 본연구에사용한타피오카변성전분은쌀가루현탁액의 breakdown과 setback 점도모두감소시키지만, 타피오카생전분은대조군쌀가루현탁액보다 breakdown 점도가증가되었고, setback 점도는감소하여쌀가루의호화촉진과노화지연에효과적인것으로나타났다. 타피오카생전분을첨가한쌀가루현탁액은가공안정성이향상되고, 노화도가감소되는것으로나타났다. 타피오카변성전분은쌀가루현탁액의 breakdown 점도를감소시켰으며, 타피오카생전분보다큰폭으로 setback 점도를감소시켜노화지연에보다효과적인것으로사료된다. Choi SY와 Shin MS(2009) 은 setback 점도는노화정도또는냉각과정에서겔구조형성을예측할수있는지표로전분용액의 setback 점도가낮으면전분용액이냉각될때겔구조형성을위한 network 형성이잘이루어지지않으며노화가잘일어나지않는다. 즉 setback 점도가높으면호화액이냉각될때단단한겔을형성할수있다고하였다. 타피오카변성전분첨가쌀가루현탁액에서 setback 점도가낮게나타났는데이는겔이냉각될때점도변화가적어 network 형성이어려워기계적인특성을나타내는경도측정결과에서타피오카변성전분첨가쿠키의경도가타피오카생전분첨가쿠키의경도보다낮게나타나는것과연관있다고사료된다. 사용된변성전분은타피오카히드록시프로필전분으로히드록시프로필화 (Hydroxypropylation) 는전분의호화온도를낮추고, 수분보유력 (water holding capacity) 과해동안정성 (freeze-thaw stability) 을개선한다고알려져있다 (Tuschhoff JV 1987, Choi MH와 Yoo BS 2007). 하이드록시프로필화는알칼리촉매하에 서 propylene oxide 를첨가하여 glucose 단위 2 번탄소위치에하이드록시프로필기를치환시켜제조하는방법으로써하이드록시필기에의해전분입자의내부결합이약해져서호화온도가낮아지고노화가억제된다. 특히하이드록시프로필화는냉해동및저장시안정성을증진시키는효과를가지고있어하이드록시프로필화전분은냉장, 냉동식품에주로사용되고있다 (Tuschhoff JV 1987, Choi MH 와 Yoo BS 2007). 이러한전분입자의약해진내부결합으로수분보유력이높아져최고점도를감소시킨것으로볼수있다 (Eliasson AC 2004). Kim SK 와 Shin MS(1992) 은아밀로펙틴함량이높은찹쌀전분이멥쌀전분보다비결정부분이많고전분입자의내부치밀도가낮아수분의흡수가높고빠르다고보고하였다. 전분의호화는함께첨가된물질의작용에의해수분흡수가증가되거나또는억제되는등첨가제의영향을직접적으로받는다. 약해진분자결합을가진타피오카변성전분첨가에의해수분흡수가빨라호화진행이빠르게되어호화온도가낮아진것으로사료된다. 3. 반죽및쌀쿠키의색도 전분을첨가한반죽과쌀쿠키색도인 L, a, b 값을측정한결과는 Table 5 에나타내었다. 타피오카생전분을첨가한반죽의 L 값은유의적인차이를보이지않았고, 타피오카변성전분은첨가군반죽의 L 값이높게나타났다. Kum 등 (1994) 의보고에따르면, 압출성형및드럼건조로제조한변성전분이생전분에비해 L 값이감소한결과로미루어볼때변성전분의첨가가반죽의명도를감소시킨것으로사료된다. 타피오카변성전분을첨가한쿠키의 L 값과 b 값은증가하였으며, a 값은감소하였다. 타피오카생전분첨가쿠키의경우는일정한경향이나타나지않았다. 4. 쌀쿠키의퍼짐성 쿠키의품질에서관능적요인과함께중요한인자로작용하는것이퍼짐성인데쿠키반죽을성형한후굽는과정에서쿠키의반죽이바깥쪽으로밀려퍼지면서두께가감소하고직경이커지는현상을뜻하며이를퍼짐성이라하고, 반죽시간 Korean J. Food Cookery Sci. Vol. 29, No. 5(2013)

474 이준경 오성훈 임재각 Table 5. Color value of dough and rice cookie made of wet-milled rice flour added with starches Dough Cookie (Top) Color value Control Addition rate of starches (%) 1) Tapioca modified starch 5 10 15 5 10 15 L 76.9±0.6 c2) 77.9±0.9 abc 77.5±1.0 bc 77.0±1.1 c 78.0±0.4 abc 79.0±0.3 a 78.7±0.8 ab a 4.8±1.3 ab 3.0±0.2 c 5.1±0.2 a 3.8±0.5 bc 1.5±0.1b d 1.2±0.2 d 1.4±0.1 d b 23.1±0.7 e 25.4±0.8 bc 24.7±0.5 cd 24.5±0.2 d 27.9±0.4 a 26.0±0.2 b 25.6±0.3 b L 78.3±1.0 b 77.8±0.5 b 79.1±1.1 b 78.9±0.6 b 78.2±0.6 b 80.4±0.5 a 81.0±0.5 a a 7.0±2.1 a 5.7±0.4 ab 2.7±0.6 cd 5.8±1.4 ab 4.4±0.1 bc 2.3±0.3 d 2.0±0.2 d b 26.6±0.5 d 29.4±1.2 b 29.5±0.6 b 27.5±0.4 cd 31.7±0.7 a 29.1±0.1 b 28.6±0.4 b Cookie (Bottom) L 67.1±3.5 ab 64.6±2.6 ab 65.2±2.3 ab 69.1±0.5 a 63.0±3.1 b 68.0±1.2 a 67.3±1.8 a a 12.9±0.7 a 13.6±1.1 a 12.7±1.3 a 13.0±1.3 a 13.9±1.6 a 11.8±0.8 a 12.0±1.1 a b 32.7±0.5 bc 33.7±0.7 ab 33.8±1.0 ab 31.1±1.7 c 35.3±0.2 a 34.8±0.9 a 35.0±0.6 a 1) Starches were added in 5, 10 and 15% substituted for rice flour 100g. 2) Different superscripts in a row indicate significant differences at p<0.05 by Duncan's multiple range test Table 6. Spreadability of cookie made of rice flour added with starches Addition rate of starches (%)1) Control Tapioca modified starch 5 10 15 5 10 15 Spreadability 3.061±0.14 c2) 3.076±0.14 c 3.138±0.06 bc 3.065±0.11 c 3.277±0.11 ab 3.370±0.13 a 3.282±0.02 ab 1) Starches were added in 5, 10 and 15% substituted for rice flour 100g. 2) Different superscripts in a row indicate significant differences at p<0.05 by Duncan's multiple range test 과방법, 굽는온도및시간, 쿠키의재료및가루의수분흡수율등의영향을받는것으로알려져있다 (Gisslen 2001). 타피오카전분을첨가한쌀쿠키의퍼짐성 (Spread ratio) 은 Table 6 과같다. 타피오카전분첨가에의한쿠키의퍼짐성은생전분첨가군은 10% 첨가군에서만증가하였고, 변성전분첨가군모두에서무첨가군보다증가하였고 10% 첨가군에서제일높게나타났다. 생전분첨가군보다변성전분첨가군에서큰증가폭을나타내었다. 쿠키의퍼짐성은반죽의농도, 오븐의굽는온도, 반죽내성분에따라영향을많이받게되는데, 타피오카생전분의보수력증진성질 (Ahn GJ. 2005) 에의해점도가감소하여묽어짐에따라퍼짐성이증가하여쿠키의직경이증가하게된다 (Han HS 2004, Mehri H 와 Francis B 2009). 타피오카전분을첨가할경우겔강도의증가와함께보수력을증진시킬수있다 (Ahn GJ. 2005) 즉전분의하이드록시프로필화에의해수분보유력증가로반죽내수분이자유수상태로존재할경우반죽의점성이낮아져퍼짐성지수가높아질수도있다 (Kissell LT 와 Yamazaki WT 1975). 하이드록시프로필화쌀전분겔이망상구조를형성하여생전분보다낮은탄성을가지며, 또한전분내에하이드록시기의도입은전분입자내부의수소결합을방해하여장시간노화과정에도낮은저장탄성률 (storage modulus G') 을유지하게된 다고하여궁극적으로쌀전분에하이드록시기의도입은전분분자의재회합을방해함으로써노화를지연시켜준다는보고가있다 (Shon KJ 와 Yoo BS 2006.) 타피오카변성전분은타피오카생전분보다큰폭으로 setback 점도를감소시켜노화지연에보다효과적인것으로사료된다. 5. 반죽및쌀쿠키의밀도 밀도는반죽의팽창정도를나타내므로쿠키의품질관리에있어서중요한항목으로완성된쿠키의향과색에영향을미칠수있다 (Cho 등 2006). 밀도가낮으면쿠키가딱딱하여기호도가감소하고, 밀도가높으면쿠키가쉽게부서져상품성이떨어질수있다고보고된바있다 (Shin 등 2007). 타피오카전분을첨가한반죽및쌀쿠키의밀도를측정한결과는 Fig. 2 에나타내었다. 타피오카생전분첨가에의한반죽의밀도는유의적인차이가나타나지않았다. 타피오카변성전분을첨가한쿠키반죽은무첨가군에비하여감소하였으나첨가량증가에따른유의적인차이는나타나지않았다. 타피오카생전분을첨가한쿠키의밀도는무첨가군의밀도 0.968g/mL 에비하여 0.897~0.944g/mL 로유의적으로감소하였다. 타피오카변성전분을첨가한쿠키의경우에서도첨가량증가에따라밀도가 0.846~0.900g/mL 로유의적인감소를나타 한국식품조리과학회지제 29 권제 5 호 (2013)

타피오카전분의첨가가쌀쿠키의품질특성에미치는영향 475 내었으며, 타피오카생전분첨가의경우보다타피오카변성전분첨가의경우가더크게감소하였다. 반면쿠키의밀도는반죽의밀도에비해 0.12~0.18 g/ml 로전체적으로감소하였다. 이는쿠키를굽는과정에서발생한수분증발에의한것으로사료된다. 생전분과변성전분모두에서쿠키의밀도는감소하였다. 았으나변성전분첨가반죽의경도는첨가량의증가에따라유의적으로감소하였다. 타피오카하이드록시필전분은하이드록시필기에의해전분입자의내부결합이약해져서호화온도가낮아지고노화가억제되는특성이있다. 이러한특성때문에반죽의경도를감소시키는연화작용을하는것으로사료된다. 타피오카생전분을첨가한쿠키경도의측정결과, 반죽의경우에서와는다르게타피오카전분의첨가는경도를감소시켰으며, 타피오카변성전분을첨가한쿠키의경도는유의적으로크게감소하는것으로나타났다. 7. 관능평가 Fig. 2. Bulk density of dough and cookie made of rice flour added with starches a,b Means with different letters in the same starches indicate significant difference from each addition rate of starches at p<0.05 by Duncan's multiple range test. TS; tapioca starch, TMS; tapioca modified starch 6. 반죽및쌀쿠키의경도 반죽의경도와부드러움을조절하기위하여식품산업에서사용되고있는타피오카생전분과변성전분을첨가한반죽과쌀쿠키의경도를측정한결과는 Table 7 에나타내었다. 타피오카생전분첨가반죽의경도는유의적인차이가나타나지않 타피오카생전분과변성전분의첨가량을달리하여제조한쌀쿠키의관능적특성을알아보기위하여전분첨가쿠키와무첨가쿠키의관능적특성을각각살펴보았고외관, 색, 맛, 향, 단단한정도, 바삭거림정도, 촉촉한정도, 부드러운정도, 목넘김이거친정도및전반적인기호도의평가항목에대한선호도를평가하였으며그결과는 Table 8 과같다. 타피오카생전분 10% 첨가군이전반적인기호도, 단단한정도, 바삭거리는정도, 부드러운정도, 맛, 색및향의항목에서높은선호도를나타내었다. 외관과향의경우에는타오카생전분 15% 첨가군이가장높은선호도를나타내었으며, 단단한정도와부드러운정도의경우에는 10% 첨가군과함께가장높은선호도를나타내었고, 목넘김이거친정도의경우에는타오카전분 5% 첨가군이가장높은선호도를나타내었다. 외관의경우타피오카생전분첨가량이증가할수록선호도가증가하였고, 촉촉한정도의경우에는유의차가나타나지않았다. 타피오카변성전분을첨가한경우에는 15% 첨가군이전반적인기호도, 외관, 향, 부스러지는정도의항목에서무첨가군보다높은선호도를나타내었고, 10% 첨가군이외관, 색, 향, 단단한정도, 부드러운정도및목넘김이거친정도의항목에서무첨가군보다높은선호도를나타내었다. 목넘김이거친정도에서유의성은없으나무첨가군보다높은선호도를나타내었다. 촉촉한정도에서는첨가군간에유의성이나타나지않았다. 타피오카생전분과타피오카변성전분의첨가로전반적인관능특성상기호도가개선되었으며, 특히타피오카생전분 10% 첨가군이타피오카변성전분첨가군보다전반적인기호도, 단단한정도, 바삭거리는정도, 외관, 맛및색의항목에서큰개선효과가큰것으로나타났다. 그러므로타피오카생전분과타피오카하이드록시프로필전분은쌀쿠키의관능적기호도개선에기여하는것으로나타났다. Table 7. Hardness of cookie made of rice flour added with starches Addition rate of starches (%) 1) Control Tapioca modified starch Hardness 5 10 15 5 10 15 Dough 295.7±28.3 a2) 292.53±33.3 a 293.5±28.1 a 277.2±31.3 a 265.1±38.7 bc 237.6±25.1 bc 219.5±12. 9 c Cookie 911.8±45.5 a 762.0±132.9 b 788.0±154.6 b 686.3±84.4 bc 631.0±116.3 cd 606.2±79.5 cd 543.7±63.9 d 1) Starches were added in 5, 10 and 15% substituted for rice flour 100g. 2) Different superscripts in a row indicate significant differences at p<0.05 by Duncan's multiple range test Korean J. Food Cookery Sci. Vol. 29, No. 5(2013)

476 이준경 오성훈 임재각 Table. 8. Sensory characteristics of cookie made of rice flour added with starches Addition rate of starches (%) 1) Sensory characteristics Control Tapioca modified starch 5 10 15 5 10 15 Appearance 5.5±1.9 c2) 6.5±1.7 bc 7.0±1.8 ab 7.9±1.1 a 5.5±1.2 c 5.4±0.9 c 5.5±1.4 c Color 6.2±1.0 b 7.3±1.1 a 7.3±0.5 a 6.8±0.6 ab 6.5±1.1 ab 6.7±0.7 ab 6.4±1.3 ab Flavor 4.8±0.6 b 5.4±1.7 ab 5.8±1.2 a 5.8±0.9 a 5.6±1.0 ab 5.8±1.4 a 5.8±0.7 a Hardness 5.2±0.9 c 7.0±0.7 a 7.0±0.4 a 5.9±1.0 bc 5.3±1.3c 6.1±0.7 b 5.7±0.9 bc Brittleness 4.9±1.0 c 6.3±0.5 ab 6.7±0.5 a 5.8±0.7 b 5.6±1.3 bc 5.7±1.0 bc 5.9±1.0 ab Taste 4.7±1.0 b 5.6±1.2 a 6.3±1.0 a 5.5±1.0 ab 5.8±1.0 a 5.9±1.1 a 6.3±1.1 a Moistness 5.3±1.1 a 5.6±0.9 a 5.9±1.2 a 5.3±1.3 a 5.7±0.7 a 5.6±1.1 a 5.5±1.0 a Softness 5.1±1.0 b 6.2±0.7 a 6.2±1.1 a 5.3±1.2 ab 5.7±1.0 ab 5.8±0.9 ab 5.2±1.0 b Sandiness 5.0±1.0 b 6.3±0.9 a 5.5±1.5 ab 4.8±1.9 b 5.3±1.0 ab 5.8±1.3 ab 5.2±1.1 b Overall acceptability 4.9±1.0 c 6.7±1.0 ab 7.0±1.1 a 6.0±1.1 b 5.8±0.9 b 6.0±1.0 b 6.2±1.0 ab 1) Starches were added in 5, 10 and 15% substituted for rice flour 100g. 2) Different superscripts in a row indicate significant differences at p<0.05 by Duncan's multiple range test IV. 요약및결론 본연구에서는타피오카생전분과변성전분첨가가쌀쿠키의품질특성에미치는영향을조사하였다. 습식쌀가루의 5%, 10% 및 15% 를생전분과변성전분으로대체하여첨가한가루의 RVA 에의한호화특성과쌀쿠키의색도, 퍼짐성, 밀도, 경도, 관능평가를실시하였다. 쌀가루의 RVA 호화특성을조사한결과, peak, trough 및 final viscosity 의점도변화는타피오카변성전분첨가에따라유의적으로감소하였고, 생전분보다변성전분이이들점도변화에큰영향을주는것으로나타났다. 타피오카생전분첨가쌀가루는가공안정도가높아지고, 노화도가감소되는것으로나타났다. 타피오카변성전분은타피오카생전분보다큰폭으로노화도를감소시켜노화지연에보다큰효과가나타났다. 타피오카변성전분첨가로호화개시온도가낮아졌고, 타피오카생전분첨가로쌀가루의호화시간이단축되었다. 타피오카변성전분첨가쿠키의 L 값과 b 값은증가하였으며, a 값은감소하였다. 쿠키의퍼짐성은타피오카변성전분에의해증가하였고, 10% 첨가할때가장높았다. 반죽의밀도는타피오카변성전분첨가로감소하였고, 쿠키의밀도는타피오카생전분과타피오카변성전분첨가로감소하였으며, 타피오카변성전분첨가로타피오카생전분보다더큰폭으로감소하였다. 반죽의경도는타피오카변성전분첨가로유의적으로감소하였다. 타피오카생전분과변성전분모두쌀쿠키의경도를유의적으로감소시켰으며, 타피오카변성전분이유의적으로더크게감소시켰다. 쌀쿠키의관능평가결과무첨가군은전체적으로전분첨가군보다선호도가낮았으며, 타피오카생전분과타피오카변성전분의첨가로전반적인관능특성상선호도가개선되었다. 타피오카생전분 10% 첨가군이전반적인기호도, 단단한정도, 바삭거리는정도, 색, 부드러운정도, 맛및향의항목에서, 15% 첨가군이외관의항목에서가장높은선호도를나타내었다. 타 피오카변성전분을첨가한경우에는 15% 첨가군이전반적인기호도, 맛, 부스러지는정도, 향의항목에서, 10% 첨가군이단단한정도, 향, 맛, 색의항목에서높은선호도를나타내었다. 그러므로타피오카생전분과타피오카변성전분은쌀쿠키의관능적선호도개선에기여하는것으로나타났다. 본연구결과타피오카생전분과타피오카변성전분첨가로쌀쿠키의품질을향상시키고, 관능적선호도가상승하였음을알수있었다. 그러므로이결과를통해쌀쿠키제조시타피오카생전분과변성전분의사용으로반죽및쌀쿠키의품질특성및관능적선호도를조절하는데기여할것이라사료된다. 참고문헌 AACC. 2000. Approved Methods of the AACC. 10th ed. Method 61-02. American Association of Cereal Chemists, St. Paul, MN, USA. Ahn GJ. 2005. Quality characteristics of the chol-pyon added tapioca powder. Korean J Culinary Research 11(3): 179-189 Aleksandra T, Miroslav H, Tamara D. 2010. Rheological, textural and sensory properties of gluten-free bread formulations based on rice and buckwheat flour. Food Hydrocolloids 24: 626-632 AOAC. 1990. Official Methods of Analysis. 15th ed. Association of Official Analytical Chemists, Washington, DC, USA. p.788 Cho HS, Park BH, Kim KH, Kim HA. 2006. Antioxidative effect and quality characteristics of cookies made with seatangle powder. Korean J Food culture 21: 541-549 Choi MH, Yoo BS. 2007. Dynamic rheological properties of 한국식품조리과학회지제 29 권제 5 호 (2013)

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