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1 Korean J Food Cook Sci Vol. 34, No. 1, pp. 96~104 (2018) pissn eissn 혼합쌀가루로조절한아밀로스함량이글루텐프리쌀컵케이크의품질특성에미치는영향 송난주 김지명 1 신말식 전남대학교식품영양학과, 1 올라이스 Effects of Amylose Content Controlled by Blended Rice Flours on the Quality Characteristics of Gluten-Free Rice Cupcake Nan Ju Song Ji Myoung Kim 1 Malshick Shin Department of Food and Nutrition Chonnam National University, Gwangju 61186, Korea 1 Allrice Co. Ltd., Nano Bio Research Center, Jeonnam 57248, Korea Abstract Purpose: To determine the optimal amylose content of rice flour to make gluten-free rice bakery products, blended rice flours with high amylose contents and waxy rice flours were used. Methods: The physicochemical and pasting properties as well as particle size distribution of blended rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%) and quality characteristics of rice cupcakes were investigated. Results: Solubilities of blended rice flours decreased with increasing amylose contents. Total and damage starch contents ranged % and %, respectively. Particle sizes of all flours were distributed in two peaks at µm (free starch granules) and at 100 µm (cells) fractions. The initial pasting temperature and setback viscosity increased while peak viscosity decreased with increasing amylose contents. Hardness of rice cupcake showed minimum values in the range of 15-17% amylose contents. Adhesiveness of rice cupcake with waxy rice flour showed the highest values. Rice cupcakes prepared from blended rice flours with 15% amylose contents had not only the highest volume and homogeneous air cells but also the highest scores in the acceptability test. Conclusion: Based on the above results, it is suggested that the amylose content of rice flour, blended or not, should be an important factor in making bakery products. Key words: amylose content, blended rice flour, gluten-free, rice cupcake, particle size distribution Ⅰ. 서론 쌀은옥수수, 밀을비롯한세계 3 대작물중하나로우리나라를비롯한전세계인구의약절반이주식으로사용하고있는중요한곡물자원이다. 최근서구화된식습관과수입및가공식품시장의발달등으로인하여연간 1 인당쌀소비량은지속적인감소추세에있으며 2015 년 62.9 kg 에서 2016 년에 61.9 kg 으로 1 kg, 2017 년에는 61.8 kg 으로 0.1 kg 감소하였다 (Statistics Korea 2018). 반면 2016 년쌀생산량은 417 만 7 천톤에서 2017 년 397 만 2 천톤으로감소하였지만 (Statistics Korea 2017) 쌀자급율은 100% 를유지하고있다. 그러나쌀은정부비축미가지속적으로 증가할뿐만아니라수입된쌀도재고량이증가하면서쌀을활용하는데더많은관심을가져야하는실정이다. 따라서밀가루를대체할가공용쌀가루의생산증가가필요하기때문에용도별쌀가루에대한품질지표가요구되고있다. 일본은글루텐프리쌀가루로제빵, 제과및요리용과면용 3 가지로분류하여그기준항목으로입자크기, 아밀로스함량, 수분함량, 전분손상도를제시하였다 (Ministry of Agriculture, Food and Rural Affairs 2016). 우리나라에서도 2017 년쌀가루의용도별기준을발표하였으나지속적인보완이필요한실정이다. 밀, 보리, 귀리등맥류에들어있는불용성단백질인글루테닌 (glutenin) 과글리아딘 (gliadin) 이물과함께반죽 Corresponding author: Malshick Shin, Division of Food and Nutrition, Chonnam National University, 77, Yongbong-ro, Buk-gu, Gwangju 61186, Korea ORCID: Tel: , Fax: , address: msshin@chonnam.ac.kr Korean Society of Food and Cookery Science This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( nses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

2 Korean J Food Cook Sci 아밀로스함량이쌀컵케이크의품질특성에미치는영향 97 되었을때결합되어만들어지는성분인글루텐은밀알레르기반응과면역적인반응으로인한셀리악병 (Celiac disease) 을일으키기도한다 (Battais F 등 2008, Shewry PR 2009). 전세계인구의약 1% 가유전적으로소장내융털돌기에염증으로인해소화흡수가되지않아생기는이질환은글루텐이포함되지않은글루텐프리식품을섭취해야만건강하게살아갈수있다 (Sumnu G 등 2010, Turabi E 등 2010). 쌀에는글루텐이없고곡류중단백가가높으며나트륨도없을뿐아니라경제성과접근성이좋아글루텐프리제품의중요한소재로여겨지고있다 (Turabi E 등 2010, Kim JM & Shin M 2014). 쌀가루에는글루텐을형성하는단백질이없기때문에밀가루와같이글루텐함량을기준으로나눌수없으므로쌀가루의품질에영향을줄수있는요인과밀가루를대체할수있는쌀가루의기본규격등을파악하여쌀가루품질지표를제시해야한다. 밀가루에는제분과정중에얻어지는가루의단백질함량과전분함량이달라입자분포도를살펴보았을때입자가 100 μm 에서최대피크를보이는분획과밀의큰전분입자크기인 μm 에서피크를보이는분획을확인할수있다. 중요한점은세포가그대로있는분획과유리된전분이있는분획이공존한다는것인데, 밀가루대체쌀가루의경우도반죽시물을흡수하는데용이한유리전분입자가혼합되어있어야하므로입자크기분포양상이밀가루처럼두개의분획을나타내야한다고알려져있다 (Kim JM 2016). 멥쌀의아밀로스함량은쌀이나쌀가루의조리특성에영향을미치는중요한요인으로 (Lee SH 등 1989), 이화학적특성및호화특성등에영향을주어쌀가공식품의품질에중요한요소로작용한다고알려져있다 (Cai J 등 2015, Kong X 등 2015). 아밀로스는직선상의글루코스고분자로함량이높으면가열냉각에의해삼차원적그물망구조로아밀로스겔을형성하여그정도에따라텍스처가달라져제품의품질에영향을미친다. 특히밀가루대체쌀가공식품에이용되는쌀가루의경우에도제품구조형성에중요한아밀로스함량의최적조건을결정하는것이매우필요하다. 쌀가루에대한연구는쌀의품종, 제분방법등에따른이화학적성질에관한연구 (Fari MJM 등 2010, Lin Q 등 2011, Joy EE & Ledogo N 2016, Leewatchararongjaroen J & Anuntagool J 2016) 및아밀로스함량이쌀식빵의특성에미치는영향 (Kum JS 1998), 쌀품종차이가글루텐프리쌀식빵의품질에미치는영향 (Cornejo F & Rosell CM 2015) 에관한연구등단일품종의쌀가루를사용하였지만두가지품종의쌀로만든쌀가루를혼합함으로써아밀로스함량을조절한글루텐프리쌀베이커리제품의품질특성에대한연구는없는실정이다. 따라서본연구에서는고아밀로스쌀의활용도및쌀가루의품질지표기준을확인하고자고아밀로스품종인고아미와찹쌀계열인신선찰을수침후저온건조하여분쇄하는쌀가루제분방법을이용하여쌀가루를제조하였다. 쌀가루의혼합비율을달리하여아밀로스함량이다른혼합쌀가루를제조하고이화학적특성과입도분포도및호화특성을측정하였으며, 이쌀가루로글루텐프리쌀컵케이크를제조하여품질특성을확인하였다. Ⅱ. 재료및방법 1. 재료농촌진흥청국립식량과학원남부작물부 (Miryang, Korea) 에서육종한고아밀로스품종인고아미를구입하였고찹쌀계열인신선찰은죽암농장 (Goheung, Korea) 에서구입하여백미로도정하여사용하였다. 쌀컵케이크제조를위한재료로는혼합쌀가루, 설탕 (Samyang, Seoul, Korea), 쌀눈유 (CJ Cheiljedang, Incheon, Korea), 청주 (Lotte Liquor, Gunsan, Korea) 및소금 (Namdofood, Damyang, Korea), 달걀은시험당일에지역마트에서신선한것으로구입하여사용하였다. 2. 쌀가루의제조쌀은낟알상태로 3회수세하여상온 (18±3 C) 에서 6시간수침한다음 1시간동안물기를제거한후저온 (20±3 C) 에서낟알상태로건조하였다 (Shin M 등 2010, Kim JM & Shin M 2014). 건조된쌀의수분함량이 12% 가되었을때 160 mesh의체가내장된제분기 (Pyungjin Machinery Co., Gwangju, Korea) 로쌀가루를제조하고저온에보관하면서시료로사용하였다. 3. 혼합쌀가루의제조신선찰과고아미쌀가루를각각 1:0, 2:1, 1:1, 2:3, 1:2, 1:3, 1:5, 0:1의비율로정확히혼합하여아밀로스함량이 0, 8, 12, 15, 17, 19, 21, 25% 인혼합쌀가루를제조하여시료로사용하였다. 4. 혼합쌀가루의특성측정 쌀가루의이화학적특성측정혼합쌀가루의겉보기아밀로스함량은 Williams PC 등 (1970) 의방법으로측정하였다. 쌀가루 20 mg( 건물당 ) 과 0.5 N KOH(Daejung Chemical, Incheon, Korea) 10 ml 를 vial에넣고마그네틱바 (Φ mm) 로교반하면서알칼리호화를시켰다. 호화액을 100 ml 용량플라스크에증류수로정용하고이중 10 ml를취하여 50 ml 용량플라스크에넣고, 0.1 N HCl(Daejung Chemical) 5 ml, ; 34(:96-104

3 98 송난주 김지명 신말식 Korean J Food Cook Sci 요오드용액 (0.2% I 2/2% KI; Yakuri Pure Chemicals Co., Ltd., Osaka, Japan) 0.5 ml 를첨가발색후실온에서 20 분간방치하여안정화시켰다. 분광광도계 (Optizen pop, Mecasys Co., Ltd., Daejeon, Korea) 를이용하여 650 nm 에서흡광도를측정하여표준곡선으로부터아밀로스함량을계산하였다. 표준곡선은 Montgomery EM & Senti FR (1958) 의방법으로동진벼전분에서아밀로스와아밀로펙틴을분리하여일정비율로혼합하고위의방법을적용하여실시하였으며, 표준곡선식은 Y = X 로결정계수 (R 2 =0.996) 가매우높았다. 팽윤력과용해도는 Schoch TJ(1964) 의방법을이용하여 80 C 에서측정하였다. 50 ml 원심분리관에혼합쌀가루 0.5 g( 건량기준 ) 와증류수 30 ml 를넣고마그네틱바 (Φ mm) 를이용하여분산시킨후, 80 C 항온수조 (vs-12055w1, Vision Scientific, Daejeon, Korea) 에서 30 분간교반기를이용하여저어준뒤바로찬물에냉각시켰다. 마그네틱바를제거한후 5,000 rpm 에서 30 분간원심분리 (Supra 22K, Hanil Science Industrial Co., Ltd., Seoul, Korea) 하였다. 원심분리후침전된시료의무게를측정하고미리항량하여건조시킨용기에분리된상징액을부어 105 C dry oven(of-22gw, Jeiotech.com, Daejeon, Korea) 에서건조한무게를측정하였다. 팽윤력과용해도는다음의식을이용하여용해도를계산하였다. 용해도 (%) = 상징액의건조무게 (g) 100 시료의무게 (g) 침전된쌀가루의무게 (g) 팽윤력 (g/g) = 100 시료의무게 (g) (100 % 용해도 ) 혼합쌀가루의총전분함량은 Megazyme kit(k-tsta Megazyme International Ltd., Wicklow, Ireland) 로 AACC 의방법에따라측정하였고, 손상전분함량은 Starch damage kit(k-sdam Megazyme International Ltd.) 를사용하여 AACC 에따라측정하였다 (AACC 201. 쌀가루의입자크기분포도측정혼합쌀가루의입자크기분포는 LS particle size analyzer(ls 100Q, Coulter International Co., Miami, FL, USA) 를사용하여분석하였다. 3) 호화특성측정혼합쌀가루의호화양상은신속점도측정기 (rapid visco analyzer, RVA; 3D, Newport Scientific Pty, Ltd., Narrabeen, Australia) 를이용하여측정하였다. RVA 용 canister 에시료 3 g( 수분함량 12% 기준 ) 에증류수 25 ml 를가하여담고 0-1 분간은 50 C, 분은 95 C 까지상승, 분은 95 C 로유지, 분은 50 C 까지냉각, 분은 50 C 를유지하면서점도를측정하였다. 측정치는호화개시온도 (initial pasting temperature), 최고점도 (peak viscosity, P), 최소점도 (trough viscosity, T), 50 C 에서의냉각점도 (final viscosity, F) 를나타냈고, setback(f-t) 과 breakdown(p-t) 점도를계산하였다. 5. 혼합쌀가루로제조한컵케이크의품질특성측정 쌀컵케이크의제조컵케이크의제조방법은 Kim JM & Shin M(2014) 의방법을일부수정하여실시하였다. 혼합쌀가루를이용한컵케이크반죽의배합비는쌀가루 50 g, 전란 100 g, 설탕 40 g, 소금 0.7 g, 쌀눈유 10 g, 청주 10 g으로하였다. 설탕, 소금, 달걀을볼에넣고휘핑기로저어주며혼합물온도를 40 C로중탕한다음믹서기 (800-J, Spar Food Machinery MFG, Co., Ltd, Taichung city, Ta-Li, Taiwan) 를사용하여 3단고속으로 3분동안혼합한후 1단저속으로 30초동안부드럽게균질화하여혼합물을제조하였다. 체를 2번친쌀가루를믹싱보울에넣고혼합한다음쌀눈유와청주를넣고잘혼합하였다. 비중은 0.38로조절하여컵케이크팬 (Φ5 cm) 에반죽 25 g을넣고 170/150 C 의오븐 (Deck oven, Sam Mi Ind. Co., Seoul, Korea) 에서 22분간구웠다. 쌀컵케이크는구운후실온에서 1시간냉각하여시료로사용하였다. 쌀컵케이크의형태관찰쌀컵케이크의외형적인특성은제조후실온에서 1 시간냉각한다음전체외관및내부단면을디지털카메라 (EOS 400D, Canon, Tokyo, Japan) 로촬영하여비교관찰하였다. 3) 쌀컵케이크의중량, 부피, 비체적쌀컵케이크를방냉한후무게 (g) 를측정하여평균값으로나타내고, 부피는좁쌀을이용한종자치환법으로측정하였으며무게와부피의측정값으로비체적 (ml/g) 을구하였다. 4) 쌀컵케이크의텍스처측정텍스처특성은구워진컵케이크를실온에서 1 시간냉각후 crumb 부분을 cm 3 로잘라서 texture analyzer (TA-XT plus, Stable Micro Systems, Ltd., Surrey, England) 를이용하여 10 회반복압축실험을실시하였다. TPA 로부터경도 (hardness), 응집성 (cohesiveness), 탄성 (springiness), 부착성 (adhesiveness), 씹힘성 (chewiness), 회복력 (resilience) 의특성치를비교하였다. 2018; 34(:

4 Korean J Food Cook Sci 아밀로스함량이쌀컵케이크의품질특성에미치는영향 99 5) 관능평가본연구에서실시한관능평가는전남대학교생명윤리위원회의심의를받아진행하였다 (Approval Number: HR 관능평가원은호텔조리학과학부생 15 명을선정하여평가전시료와평가방법에관한충분한설명후반복실시되었다. 차이조사및전반적품질에관한기호도조사를 9 점척도법으로평가하였다. 차이조사는외관 ( 표면및내부색, 표면매끄러움, 기공균일성, 부푼정도 ), 냄새 ( 이취, 향미 ), 맛 ( 단맛, 고소한맛 ) 및텍스처 ( 경도, 부착성, 탄력성, 씹힘성, 촉촉함, 부드러움 ) 을측정하였다. 기호도조사는외관, 냄새, 맛, 텍스처, 전반적인품질을비교평가하였다. 6. 통계처리모든실험은 3번이상반복하였고결과는평균과표준편차로나타내었다. 통계처리는 SPSS Statistics(ver. 12.0, SPSS Inc., Chicago, IL, USA) 를사용하여 ANOVA에의해분산분석을실시하였다. p<0.05 수준에서 Duncan's multiple range test로유의성을검증하였다. Ⅲ. 결과및고찰 1. 쌀가루의이화학적특성혼합쌀가루의겉보기아밀로스함량측정결과, 아밀로스함량은 % 로유의적인차이가나타났다 (Table. 이는고아미쌀가루의겉보기아밀로스함량 25% 와신선찰쌀가루의겉보기아밀로스함량 0% 를일정비율로혼합한것으로혼합쌀가루가잘혼합되었음을알수있었다. 아밀로스함량에따른혼합쌀가루의팽윤력은유의적차이가나타나지않았으나용해도는혼합쌀가루 의아밀로스함량이높아질수록낮아졌으며유의적인차이를보였다. 이는고아미쌀가루의경우 80 C 에서아밀로스용출이낮기때문이며고아밀로스전분의경우전분의호화온도가높은것과상관이있을것으로생각되었다. 즉아밀로스함량이높아질수록가열중에용출되는전분분자가적기때문으로볼수있다 (Choi SY & Shin MS 2009). 혼합쌀가루의총전분함량은 % 의범위로혼합쌀가루의아밀로스함량에따라유의적인차이를보였다. 손상전분은 % 로측정되었으며아밀로스함량이증가할수록유의적으로낮아졌다. 총전분및손상전분함량은신선찰과고아미쌀품종특성의영향이있을것이라고유추해볼수있었다. 본실험에사용된제분방법은쌀을수침하여건조및분쇄하는과정을거치는데, 수침과정에서쌀알내부로물이침투하여제분과정중손상정도를낮춘다는선행연구의보고 (Kim RY 등 2009, Kim JM 2016) 와같이손상전분함량은모두 10% 미만의낮은수치로나타났다. 2. 입자크기분포도밀가루는가공시단백질인글리아딘과글루테닌에물이흡수되어반죽에의해글루텐을형성하여수화된상태가된다. 즉글루텐단백질은흡수된물을가열과정에서전분으로재분배해주는역할을하지만쌀가루에는글루텐이없어전분이호화되기위해충분한물이반죽에존재해야하므로물을흡수하는데용이한유리전분입자분획이필요하다. 따라서본실험에사용된방법으로제분된쌀가루에유리된전분입자가포함되어입자크기분포양상이두개의봉우리로나타나는지를확인하기위하여입자분포도를살펴보았다. Fig. 1에서와같이모든혼합쌀가루에서유리된전분입자분획인 μm에서 Table 1. Apparent amylose content, solubility, swelling power, total starch content and damaged starch content of Sinseonchal and Goami blended rice flours with different flour ratio Amylose content (%) of blended rice flour Apparent amylose content (%) Solubility at 80 C (%) Swelling power at 80 C (g/g) Total starch content (%) Damaged starch content (%) BRF0 0.00±0.16 h 29.24±10.40 a 9.09± ±0.35 a 8.29±0.09 a BRF8 7.89±0.13 g 20.55±2.18 b 7.67± ±2.02 ab 7.73±0.03 b BRF ±0.12 f 12.76±0.59 bc 7.70± ±2.36 ab 7.44±0.00 c BRF ±0.11 e 13.49±2.52 bc 6.07± ±0.29 ab 7.27±0.02 d BRF ±0.10 d 8.17±0.69 c 6.87± ±0.80 ab 7.16±0.03 d BRF ±0.10 c 8.53±0.05 c 6.17± ±1.55 bc 7.02±0.04 e BRF ±0.09 c 7.25±0.23 c 5.82± ±2.62 c 6.89±0.06 f BRF ±0.08 a 6.90±0.15 c 5.20± ±0.14 c 6.60±0.09 g Data represents mean±sd. Blended rice flours (BRF) were controlled by mixing Sinseonchal and Goami rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). Values in the same column with different letters are significantly different at p<0.05 by Duncan's multiple range test ; 34(:96-104

5 100 송난주 김지명 신말식 Korean J Food Cook Sci Fig. 1. Particle size distribution patterns of Sinseonchal and Goami blended rice flours prepared with different flour ratio. Blended rice flours (BRF) were controlled by mixing Sinseonchal and Goami rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). 작은피크를나타내었고 100 μm 근처에서큰피크값을나타내어입자크기가다른 2 개의피크를보였다. 이는쌀가루에서두종류의입자가혼합되어입자크기분포양상이밀가루와비슷한두개의피크로나타남을확인하였으며이는입자크기에따른컵케이크품질을비교한보고와유사하였다 (Kim JM & Shin M 2014). 3. 호화특성호화개시온도는아밀로스함량 25% 의혼합쌀가루에서 C로가장높았으며아밀로스함량 8% 혼합쌀가루에서 C로가장낮게나타났다. 아밀로스함량이높아질수록호화개시온도는높아지는반면최고점도 (P) 는 낮아지는경향을보였다 (Varavinit S 등 2003). 고아밀로스품종의쌀가루호화온도가높은것은전분입자들이촘촘한구조로되어있기때문으로, 팽윤된전분입자가열과전단응력에대한저항성이높아져점성안정제로서이용에효과적이라고보고하였다 (Lee SH 등 1989). 한편 setback 점도값은호화후냉각과정에서네트워크변화로생기는점도차로노화정도를나타내기도하지만아밀로스겔에의해형성된메트릭스가쌀베이커리의구조를이루기때문에노화도보다는구조형성에도움을준다고설명할수있다. 아밀로스함량이높아질수록 setback 점도 (F-T) 값이증가하였다. Breakdown 점도 (P-T) 는최고점도 (P) 와최소점도 (T) 의차이로전분입자가열에붕괴되는정도를나타내며, 호화특성중열전단에대한저항성과높은상관성을보인다 (Lee JS 등 2009). 본실험에서혼합쌀가루의아밀로스함량이높아질수록낮아지는경향을보였는데이는 Jang KA 등 (1996) 이 breakdown 값과아밀로스함량은부의상관관계에있다는선행연구와일치하는값을보였다. 혼합쌀가루의아밀로스함량의증가에따라호화특성차이를나타냈고이를통해혼합쌀가루의아밀로스함량은쌀가루의가공적성에영향을미칠것으로사료되었다. 4. 혼합쌀가루로제조한쌀컵케이크의품질특성 쌀컵케이크의형태및품질특성신선찰과고아미쌀가루를혼합한쌀가루를이용하여쌀컵케이크를제조하여외관과단면의형태를관찰한결과, Fig. 2와같이아밀로스함량이낮은쌀컵케이크의부피가작은경향을보였다. 아밀로스함량이다른혼합쌀가루를이용한컵케이크의외형특성관찰결과, 특히 Table 2. Pasting properties of Sinseonchal and Goami blended rice flours prepared with different flour ratio by rapid visco analyzer Viscosity (RVU) Amylose content (%) Initial pasting of blended rice flours temp. ( C) Peak Trough Final Breakdown Setback (P) (T) (F) (P-T) (F-T) BRF ±0.49 cd ±2.71 a 99.25±2.36 c ±2.12 e 77.25±0.35 a 28.50±0.24 f BRF ±0.78 d ±3.12 b ±2.12 a ±0.29 d 41.13±5.24 b 61.88±2.42 e BRF ±0.64 bcd ±1.00 c ±1.47 b ±1.36 b 41.50±2.47 b 83.42±2.83 d BRF ±0.53 cd ±1.18 de 95.29±1.36 de ±0.41 b 39.54±0.18 b 94.92±0.94 c BRF ±0.64 bcd ±2.00 d 96.83±0.00 cd ±1.47 a 40.08±2.00 b ±1.47 b BRF ±0.67 cd ±0.47 ef 92.04±1.00 ef ±1.71 a 39.79±0.53 b ±0.71 b BRF ±0.00 bc ±0.24 f 88.21±0.06 g ±0.47 a 39.38±0.18 b ±0.53 a BRF ±0.11 a ±2.24 g 88.38±2.30 g ±2.18 c 31.38±0.06 c 95.33±0.12 c Data represents mean±sd. Blended rice flours (BRF) were controlled by mixing Sinseonchal and Goami rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). Values in the same column with different letters are significantly different at p<0.05 by Duncan's multiple range test. 2018; 34(:

6 Korean J Food Cook Sci 아밀로스함량이쌀컵케이크의품질특성에미치는영향 101 Fig. 2. Whole and cross section of cupcakes prepared from Sinseonchal and Goami blended rice flours with different flour ratio. Blended rice flours (BRF) were controlled by mixing Sinseonchal and Goami rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). Table 3. Specific gravity of batters and weight and volume of rice cupcake prepared from Sinseonchal and Goami blended rice flours with different flour ratio Amylose content (%) of blended rice flours Weight (g) Volume (ml) Specific volume (ml/g) BRF ± ±2.89 e 3.73±0.17 e BRF ± ±3.61 cd 3.98±0.14 cd BRF ± ±2.65 bc 4.14±0.11 bc BRF ± ±2.65 a 4.53±0.16 a BRF ± ±3.61 b 4.28±0.16 b BRF ± ±2.52 de 3.93±0.15 cd BRF ± ±2.52 de 3.88±0.14 cd BRF ± ±1.00 de 3.79±0.12 e Data represents mean±sd. Blended rice flours (BRF) were controlled by mixing Sinseonchal and Goami rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). Values in the same column with different letters are significantly different at p<0.05 by Duncan's multiple range test. 아밀로스함량 15% 와 17% 의혼합쌀가루로만든컵케이크에서기공이균일하고좋은부피를형성함을관찰할수있었다. 아밀로스함량이증가할수록점차부피가증가하다가아밀로스 15%, 17% 인컵케이크에서가장좋은부피를나타내었고이후아밀로스 19% 이상의컵케이크에서다시부피가감소하는경향을나타내었다 (Table 3). 부피와비체적은 Table 3 과같이각각 ml 와 ml/g 범위였으며혼합쌀가루의아밀로스함량이 15% 인시료에서부피가 ml, 비체적이 4.53 ml/g 으로가장좋은부피와비체적을나타내었다. 반면혼합쌀가루의아밀로스 0% 인신선찰가루로만든컵케이크는부피 ml, 비체적 3.73 ml/g 으로부피와비체적이가장낮았고아밀로스 25% 인고아미쌀가루컵케이크에서는 3.79 ml/g 으로비체적이낮은경향을보였다. 혼합쌀가루의아밀로스함량이높아질수록부피와비체 적값이높아지다가아밀로스 15% 인컵케이크에서가장높은값을나타내었고아밀로스함량 17% 이상의혼합쌀가루시료에서점점그값이낮아졌으며유의적인차이를보였다. 텍스처특성쌀컵케이크의텍스처특성치는 Table 4 와같았다. 텍스처특성치중경도는제품의단단한정도를나타내는데아밀로스 15% 인컵케이크에서가장낮아부드러웠으며, 아밀로스 25% 의컵케이크에서가장단단하였다. 고아미쌀은아밀로스겔을이용한쌀국수용으로개발된벼품종으로, 경도는높고부착성이낮은특성이있다 (Song YC 등 2008). 경도역시부피나비체적과비슷한양상으로컵케이크의경도가아밀로스함량 15% 인쌀가루로제조하였을때까지낮아지다가그이상의경우점차증가되는경향을나타내었다. 한편아밀로스함량 0-12% 의시료에서는부착성을보였으며특히아밀로스 0% 의신선찰쌀가루로만든컵케이크에서큰부착성을나타내었다. 탄성과응집성은각각 와 의범위였고아밀로스 0% 시료에서가장낮은탄성과응집성을보였다. 씹힘성은아밀로스 15% 의시료에서가장낮았으며아밀로스 25% 의시료에서가장높게나타나경도와유사한경향이었다. 회복력는힘을주었다가놓았을때회복되는정도로신선찰쌀가루인아밀로스 0% 의시료에서가장낮았다. 컵케이크의물성은부드럽고부착성이없는것이좋은품질로, 아밀로스함량 15% 인쌀가루로제조한컵케이크가우수하였다. Kang MY 등 (1997) 의연구에의하면쌀가루의아밀로스함량이높을수록쌀빵의탄력성은높고응집력이낮다고하였으며, Marco C & Rosell CM(2008) 는빵의부피와경도는반비례한다고하였다. 3) 관능평가아밀로스함량이다른쌀가루로제조한쌀컵케이크의 ; 34(:96-104

7 102 송난주 김지명 신말식 Korean J Food Cook Sci Table 4. Textural properties of rice cupcakes prepared from Sinseonchal and Goami blended rice flours with different flour ratio Amylose content (%) of blended rice flours Hardness (g) Adhesiveness (g.sec) Springiness Cohesiveness Chewiness Resilience BRF ±63.87 b -3.63±1.19 c 0.59±0.08 c 0.59±0.05 b ±42.11 bc 0.18±0.01 e BRF ±58.08 cd -1.66±0.84 b 0.82±0.06 ab 0.66±0.01 a ±22.84 cd 0.22±0.01 d BRF ±40.42 de -0.11±0.06 ab 0.79±0.05 b 0.63±0.02 a ±16.56 acd 0.22±0.01 d BRF ±16.39 f n.d. 0.84±0.03 ab 0.64±0.01 a ±9.69 e 0.23±0.01 c BRF ±21.15 df n.d. 0.85±0.03 ab 0.65±0.01 a ±16.36 de 0.27±0.01 b BRF ±5.09 cd n.d. 0.83±0.05 ab 0.65±0.02 a ±13.89 bc 0.24±0.01 c BRF ±52.26 c n.d. 0.89±0.03 a 0.64±0.01 a ±35.09 b 0.27±0.01 b BRF ± a n.d. 0.86±0.04 ab 0.66±0.01 a ±56.47 a 0.30±0.01 a Data represents mean±sd. n.d. means not detected Blended rice flours (BRF) were controlled by mixing Sinseonchal and Goami rice flours with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). Values in the same column with different letters are significantly different at p<0.05 by Duncan's multiple range test. Table 5. Sensory evaluation data for difference and acceptability tests of cupcakes prepared from Sinseonchal and Goami blended rice flours added with different flour ratio Appearance Flavor Texture Attributes Amylose content (%) of blended rice flours Difference test Surface color 3.6±2.2 b 5.2±2.2 a 5.5±1.5 a 6.1±1.7 a 6.1±1.5 a 5.3±1.9 a 5.5±1.1 a 6.0±1.1 a Surface smoothness 2.6±1.6 d 3.3±1.4 cd 3.9±1.5 c 6.4±2.1 ab 5.5±1.2 ab 6.6±1.5 a 5.8±1.2 ab 5.4±1.2 b Air cell uniformity 2.9±1.9 d 4.6±2.3 bc 3.7±1.7 cd 6.2±2.0 a 4.6±1.6 bc 6.7±1.8 a 5.9±1.8 ab 6.4±1.4 a Volume 2.1±1.8 d 3.0±1.0 c 5.5±1.2 c 6.5±1.6 ab 5.9±1.3 ab 7.1±1.9 a 5.5±2.0 b 6.6±1.3 ab Off-flavor 2.0±1.6 b 2.7±0.6 ab 2.6±1.5 ab 2.2±1.4 b 2.8±1.6 ab 3.7±1.2 a 3.1±1.8 ab 3.9±2.0 a Flavor 6.7±1.2 a 5.3±1.5 bc 6.3±1.2 ab 6.3±1.2 ab 5.3±1.6 bc 5.3±1.2 bc 4.6±1.5 c 5.1±1.5 c Hardness 4.4± ± ± ± ± ± ± ±2.0 Elasticity 4.3±2.1 ab 4.2±1.9 ab 5.8±1.4 a 5.7±1.8 a 4.5±2.2 a 5.7±1.9 ab 5.3±2.0 ab 3.7±2.0 b Being chewy 5.2±1.6 a 4.2±1.7 ab 5.1±1.8 a 4.9±1.2 a 4.9±1.8 a 4.8±1.2 a 4.1±1.8 ab 3.2±1.9 b Moistness 5.6±2.2 a 3.8±1.8 bc 4.5±2.0 ab 4.7±1.7 ab 4.1±1.8 bc 3.3±2.2 bc 3.9±1.8 bc 2.7±1.4 c Softness 5.9±2.0 a 3.8±1.8 b 4.7±2.2 ab 6.1±1.7 a 4.0±1.7 b 4.0±1.6 b 4.3±2.4 b 3.7±2.0 b Acceptability test Appearance 3.1±4.6 e 4.1±1.3 d 5.1±1.3 c 6.9±0.9 a 6.1±0.6 ab 6.5±1.6 ab 5.5±1.4 bc 5.4±0.9 bc Flavor 6.2± ± ± ± ± ± ± ±0.9 Taste 5.9±1.5 a 5.1±0.7 ab 5.9±1.2 a 6.0±1.1 a 5.4±0.9 ab 5.1±1.2 ab 4.8±1.1 b 3.5±1.5 c Texture 5.5±0.7 ab 4.7±1.1 bc 5.8±1.5 a 5.8±1.5 a 5.6±1. ab 5.7±1.4 ab 5.1±1.1 ab 4.3±1.1 c Overall quality 5.7±1.0 bcd 5.5±0.5 cde 6.1±1.1 bc 7.1±1.1 a 6.3±0.4 b 5.7±0.4 bcd 5.1±1.2 de 5.0±0.4 e Data represents mean±sd. Blended rice flours (BRF) were prepared with different amylose contents (0, 8, 12, 15, 17, 19, 21, and 25%). Values in the same row with different letters are significantly different at p<0.05 by Duncan's multiple range test. 차이조사결과, Table 5 와같이경도를제외하고는모두유의적인차이를보였다 (p<0.05). 외관에서표면색, 표면매끄러움, 기공균일성및부푼정도는아밀로스 0% 의찹 쌀가루컵케이크에서가장낮은점수를, 아밀로스 15% 의혼합쌀가루로만든컵케이크에서가장높은점수를받았다. 향미는아밀로스 0% 의컵케이크에서 6.67 로가장높 2018; 34(:

8 Korean J Food Cook Sci 아밀로스함량이쌀컵케이크의품질특성에미치는영향 103 은점수를받았고이취는아밀로스 0% 와 15% 로제조한컵케이크에서낮은점수를얻었다. 텍스처결과아밀로스 12-17% 의컵케이크에서탄력성과씹힘성이가장좋은점수를받았으며촉촉함과부드러움은아밀로스 0% 의컵케이크에서높은점수로평가되었다. 기호도평가결과, 향미를제외한모든항목에서유의적인차이를보였다 (p <0.05). 혼합쌀가루아밀로스 15% 의컵케이크에서외관, 맛, 텍스처와전반적인품질평가에서가장좋은점수를받았으며아밀로스함량이 17% 와 12% 인컵케이크는다음으로좋은점수를받아아밀로스함량은제과품질에영향을주며 15% 근처에서좋은품질을나타낸다고할수있다. 외관은아밀로스 0% 컵케이크가낮은점수를받았으며맛은아밀로스 0, 12, 15% 함량의컵케이크에서높은점수를받았다. 아밀로스함량이높은혼합쌀가루로만든컵케이크는외관은좋았으나맛, 텍스처, 전체적인품질평가에서낮게평가되었고그중아밀로스함량이 25% 인고아밀로스쌀가루로만든컵케이크가가장낮았다. Ⅳ. 요약및결론 베이커리제품용쌀가루의품질지표로쌀가루의아밀로스함량이영향을주는지알아보고, 고아밀로스쌀가루를사용하기위한방법을모색하고자하였다. 고아미쌀가루에신선찰쌀가루비율을달리혼합하여아밀로스함량이다른혼합쌀가루의이화학적특성과쌀가루로글루텐프리쌀컵케이크를제조하여품질특성을비교하였다. 혼합쌀가루의아밀로스함량이높아질수록용해도는낮아졌다. 입자크기는유리된전분분획인 μm 와세포분획인 100 μm 에서피크를보였다. 아밀로스함량이높을수록쌀가루의호화개시온도와 setback 점도는높아졌으나피크점도는낮아졌다. 혼합쌀가루로만든쌀컵케이크의외관은아밀로스함량 0% 에서중심부분이가라앉았고 15% 와 17% 쌀가루로만든컵케이크에서부피와비체적이높은값을보였다. 경도는아밀로스함량 15% 에서최저값을보였고부착성은 0-12% 까지나타났다. 관능평가결과, 외관, 맛, 텍스처와전반적인품질평가에서아밀로스 15% 인컵케이크가가장높은점수를나타냈다. 위의결과로부터고아밀로스쌀가루에찹쌀가루를혼합하여아밀로스함량을조절하면베이커리제품에사용할수있으며밀가루대체용쌀가루에서아밀로스함량은용도별품질기준에중요한요인임을확인하였다. Conflict of Interest No potential conflict of interest relevant to this article was reported. Acknowledgments This work was supported by Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET) through High Value-added Food Technology Development Program funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) ( ). References AACC Approve methods of analysis. 11th ed. American Association of Cereal Chemists International, St. Paul, MN, USA. Method Battais F, Richard C, Jacquenet S, Denery-Papini S, Moneret-Vautrin DA Wheat grain allergies: An update on wheat allergens. Eur Ann Allergy Clin Immunol 40(3): Cai J, Man J, Huang J, Liu Q, Wei W, Wei C Relationship between structure and functional properties of normal rice starches with different amylose contents. Carbohyd Polym 125: Choi SY, Shin MS Properties of rice flours prepared from domestic high amylose rices. Korean J Food Sci Technol 41(: Cornejo F, Rosell CM Physicochemical properties of long rice grain varieties in relation to gluten free bread quality. LWT-Food Sci Technol 62(: Fari MJM, Rajapaksa D, Ranaweera KKDS Effect of rice variety on rice based composite flour bread quality. Tropical Agric Res 21(: Jang KA, Shin MG, Hong SH, Min BK, Kim KO Classification of rices on the basis of sensory properties of cooked rices and the physicochemical properties of rice starches. Korean J Food Sci Technol 28(: Joy EE, Ledogo N The effect of variety and processing methods on the functional and chemical properties of rice flour. Int J Nutr Food Sci 5(: Kang MY, Choi YH, Choi HC Interrelation between physicochemical properties of milled rice and retrogradation of rice bread during cold storage. Korean Soc Food Sci Nutr 26(5): Kim JM, Shin M Effects of particle size distributions of rice flour on the quality of gluten-free rice cupcakes. LWT-Food Sci Technol 59(: Kim JM Characteristics of rice flours prepared from different rice varieties and development of gluten-free bakery products using them. Doctorate dissertation. Chonnam National University, Gwangju, Korea. pp Kim RY, Kim CS, Kim HI Physicochemical properties of non-waxy rice flour affected by grinding methods and steeping times. J Korean Soc Food Sci Nutr 38(8): ; 34(:96-104

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