J Korean Soc Food Sci Nutr 한국식품영양과학회지 43(12), 1896~1905(2014) http://dx.doi.org/10.3746/jkfn.2014.43.12.1896 머루를이용한 Sourdough 식빵개발 빙동주 1 김원태 2 전순실 1 1 순천대학교식품영양학과 2 창신대학교호텔조리제빵과 Development of White Bread Using Fermented Wild Grape Sourdough Dong-Joo Bing 1, Won-Tae Kim 2, and Soon-Sil Chun 1 1 Department of Food & Nutrition, Sunchon National University 2 Department of Hotel Culinary & Bakery, Changshin University ABSTRACT The purpose of this study was to manufacture white bread by substituting bakery yeast with natural starter. The general composition of wild grape, was 81.22% moisture, 0.81% ash, 0.74% crude fat, 1.58% crude protein, and 15.65% carbohydrate contents. Fermented wild grape extract was made by culturing for 4 days at 25 C. Flour was added three times to fermented wild grape extract and incubated for 36 hours at 20 C to manufacture sourdough. We investigated the quality characteristics of white bread with different amounts of fermented wild grape sourdough. The ph of dough decreased with increasing amounts of sourdough, whereas total titratable acidity of dough significantly increased. Fermentation power of dough expansion significantly increased with increasing incubation time, and control showed the highest value of 126.67%. White bread specific volume was highest in, 50% sourdough at 4.76 ml/g. Water content increased with increasing amounts of sourdough, whereas water activity was not significantly different between the samples. For texture, hardness of 50% sourdough was lowest at 19.23 g. In the sensory evaluation, color, flavor, softness and overall acceptability decreased with increasing amounts of sourdough. As a result, 50% sourdough can be considered as a baker's yeast substitute for making natural fermented bread. Key words: wild grape, sourdough, fermentation power, texture, sensory evaluation 서 최근경제발전과여성의사회진출증가, 서구화된식생활등으로인해국내쌀소비량은점차감소하고있는반면밀가루의소비는꾸준히증가하고있다 (1). 그중빵은밀가루, 소금, 설탕등과효모를혼합하여발효시킨것으로기원전 5000년경이집트에서발효빵이만들어져왔으며문화와지역에따라다양하게발전해왔다 (2). 소비자는건강에대한관심의증가로일반적으로사용하는상업적효모보다는천연효모를이용한빵을찾는소비자가증가하면서 sourdough를이용한제빵생산이증가하고있다. Sourdough는밀, 보리등을분쇄하여물을가하면효모와유산균에의해알코올발효와젖산발효가일어나면서 CO 2 를생성하고시큼한맛과향미가있는반죽이다. 19세기상업적효모가발전하기전부터제빵용천연효모로사용해왔으며 (3,4), 빵반죽시사용하고남은일부분을남겨두었다가다시빵반죽에반복적으로사용한다 (5). Sourdough 제조시사용되는곡 Received 22 August 2014; Accepted 23 September 2014 Corresponding author: Soon-Sil Chun, Department of Food & Nutrition, Sunchon National University, Jeonnam 540-742, Korea E-mail: css@scnu.ac.kr, Phone: +82-61-750-3654 론 물의종류, 물의양, 기온, 시간등은미생물학적변화에영향을주어최종제품의빵의부피, 조직감, 풍미및저장성에영향을미친다 (6-8). 또한 Liukkonen 등 (9) 은호밀 sourdough는발효과정중엽산과페놀화합물의양이증가하여호밀보다영양적가치가높아졌다고한다. 최근 sourdough 에대한관심이급증하면서다양한연구가진행되고있으며, Hwang 등 (10) 은유기산으로발효미강 sourdough를제조하여바게트에이스트양의 2/3를대체하여 sourdough를첨가했을때수분함량, 부피및풍미향상효과를보고하였다. Lee 등 (4) 은홍국을첨가한 sourdough 분말, 상업용 sourdough 분말및일반적인이스트를사용하여식빵을제조하였을때홍국을첨가한 sourdough 분말첨가식빵이저장기간중에경도변화가작고노화가늦게일어났으며소비자기호도도가장높게나타났다. 이외에도건도포를이용한천연발효액과 sourdough(11), 국내산밀가루를이용한 sourdough starter 분말첨가식빵 (12), 항균활성이있는유산균을이용한발효빵 (13), 유산균과 Bifidobacterium longum을혼합균으로사용한 flour sourdough의발효특성 (14), 야콘을이용한 sourdough starer 개발 (15), sourdough로부터젖산균과효모의분리및배양특성 (16) 에관한연구등이있다.
머루를이용한 Sourdough 식빵개발 1897 포도과에속하는머루는덩굴성식물로한국과일본에서주로분포하고있으며국내에는파주, 평창, 문경및임실과무주에서재배한다 (17,18). 예로부터머루는염증, 천식, 기관지염, 병소치료를위한민간요법으로사용되어왔다 (19). 또한머루는알칼리성식품으로비타민 B 1, B 2, B 3 및 C가풍부하며 Ca, P, Fe 등무기질함량이높고 (20,21), 열매에는 phenolic acids와 flavonoids와같은페놀화합물을다량함유하고있어천연항산화소재로각광을받고있다 (22- ). 그러나머루는신맛이강하고과육부분이적으며저장성이낮아대부분머루주스 (21) 나머루와인 (25) 또는약주 (26,27) 로이용되며, 머루를이용한가공식품연구는미비한실정이다. 따라서본연구에서는머루를이용한천연 sourdough를제조하고 10%, 30%, 50% 및 70% 를대체한식빵반죽의 ph와총산도를측정하고, 식빵의 ph, 적정산도, 비용적, 굽기손실률, 수분함량, 색도, 조직감, 내부표면관찰및관능검사를실시하여머루 sourdough 식빵의최적배합비를구명하여상업적으로현장에서이용할수있는제조조건을제시하고자한다. 재료및방법실험재료천연발효액종제조에사용된머루는전라북도무주군에서 2013년 9월말경에수확한머루를 20 C에서냉동보관하여사용하였고, 밀가루 ( 강력분, 씨제이제일제당, 양산, 한국 ), 버터 ( 롯데우유버터화이트, 롯데, 천안, 한국 ), 드라이이스트 (instant yeast, La Parisienne, Paris, France), 소금 ( 꽃소금, 샘표식품주식회사, 서울, 한국 ), 설탕 ( 백설하얀설탕, 씨제이제일제당, 인천, 한국 ) 및식물성크림 ( 뉴밀키엑스트라, 희창유업, 양산, 한국 ) 을구입하여실험재료로사용하였다. 머루의일반성분분석머루의조지방과조단백질은원소분석기 (EA 1110, Thermo Quest, Milan, Italy) 로분석하였다. 탄수화물은시료전체무게에서수분, 조회분, 조지방, 조단백질을뺀나머지값을 % 로표시하였다. 머루발효액종및 sourdough 제조멸균한병에머루 200 g, 생수 500 g, 설탕 5 g을넣고혼합한다음인큐베이터에서 4일간 25 C에서배양한후 60 mesh 체로여과하여발효액을제조하였다. 발효액종 100 g에강력분 160 g을함께넣고섞어준후반죽기를이용하여 1단 3분, 2단 5분동안반죽하여글루텐이형성되도록 1차반죽하였다. 그리고 20 C에서 12시간정도발효한후 1차반죽에강력분 230 g, 물 130 g을넣고 1차반죽과동일한방법으로발효시켜 2차반죽하였다. 다시 2차반죽 에강력분 670 g, 물 700 g을넣고반죽하여 20 C에서 12시간발효하여최종 sourdough를완성하였다. ph와적정산도측정 ph는 25 C에서 4일간배양하며매 시간마다 ph meter(ph-200l, Istek, Seoul, Korea) 로측정하였고, 적정산도 (28) 는 0.1 N NaOH로 ph 8.5까지적정한후소모된 0.1 N NaOH의양을 ml 수로나타내었다. 당도및알코올함량측정당도는시료 1 ml를 digital refractometer(hi 96801, Hanna Instruments, Cluj Napoca, Romania) 를사용하여측정하였고, 알코올함량은시료 100 ml를취하고증류하여측정하였다. 증류액은 70 ml 이상취한뒤 3차증류수를첨가하여 100 ml로용량을보정하고주정계를이용하여비중을측정하였으며, Gay-Lussac 표를주정환산표로보정하였다. 식빵의제조머루 sourdough를대체한제조한식빵의배합비는 Table 1에나타내었으며, 식빵은직접반죽법 (optimized straightdough method) 으로제조하였다. Sourdough는밀가루건물당 10%, 30%, 50%, 70% 의비율로대체하였고, 수분함량을동일하게할목적으로사용하는물의양을조정하였다. 제조공정은강력분을체에내린후버터를제외한모든재료를반죽기 (N50(ML104642), HOBART, Troy, OH, USA) 에넣어 1단에서 3분, 2단에서 2분간반죽한후버터를반죽기에넣고 1단에서 1분, 2단에서 12분 30초, 1단에서 1분간반죽하였다. 반죽의최종온도는 27±1 C로하였다. 완성된반죽은발효기 (SMDG-36, Daehung Machinery Co., Gyeonggi, Korea) 에서 90분동안 1차발효 ( 온도 32 C, 상대습도 80%) 한후, 120 g씩분할하여둥글리기하고실온 (20 C) 에서 15분간중간발효를하였다. 중간발효가끝난후가스빼기를하고성형하여틀에넣어발효기 ( 온도 32 C, 상대습도 80%) 에서반죽이팬의상단부 1 cm까지올라오는 Table 1. Formula of dough with wild grape sourdough Ingredients (g) Wheat flour 1) Wild grape sourdough 2) Butter Instant yeast Salt Vegetable cream powder Sugar Water 300 278.88 236.64 194.4 152.16 0.00 30 90 150 210 3 6 9 174.00 0.6 6 9 165.12 0.6 6 9 147.36 0.6 6 9 129.6 1) Moisture content of wheat flour: 12.27%. 2) Moisture content of wild grape sourdough: 38.23%. 0.6 6 9 111.84
1898 빙동주 김원태 전순실 시간까지 2차발효하였다. 굽기는윗불 190 C, 아랫불 180 C로예열된오븐 (Deck Oven, Shinshin Machinery Co., Busan, Korea) 에서 17분동안구웠다. 완성된식빵은실온 (20 C) 에서 1시간동안방치한후시료로사용하였다. 식빵의 ph와적정산도식빵의 ph와적정산도 (total titratable acidity) 는시료 10 g을분쇄하여발효액과동일한방법으로측정하였다. 반죽의발효팽창력식빵반죽의발효팽창력은 He와 Hoseney(29) 의방법을변형하여사용하였다. 믹싱이끝난반죽 25 g을취해 50 ml의메스실린더에넣은후상부의표면을평평하게하였다. 그리고 1차발효조건인온도 32 C, 상대습도 80% 의발효기 (SMDG-36, Daehung Machinery Co.) 에서 60분간발효하면서 15분간격으로측정한결과를다음식으로계산하였다. Fermentation power of dough expansion (%)= [(volume after first fermentation-volume before first fermentation)/ volume before first fermentation] 100 비용적과굽기손실률식빵의부피는종자치환법을사용하였다. 유채씨를이용하여 volumeter로측정한후비용적 (ml/g) 으로나타내었고, 굽기손실측정은굽기전의중량과구운후의중량차이로굽기손실률 (%) 을계산하였다. 수분함량측정식빵내부의수분함량은시료 2 g을수분측정기 (MB45, Ohaus, Greifensee, Switzerland) 를이용하여측정하였다. 수분활성도측정식빵내부의수분활성도는시료 2 g을수분활성도측정기 (HP23-AW, Rotronic, Bassersdorf, Switzerland) 로측정하였다. 색도측정식빵의색도는식빵의 crumb를취하여직경 2 cm, 높이 1 cm의 cell에넣고색차계 (Chroma Meter, CR-200b, Minolta, Osaka, Japan) 를사용하여 L( 명도 ), a(+ 적색도 /- 녹색도 ), b( 황색도 ) 값으로나타내었다. 이때사용된표준색판은 L=97.10, a=+0.13, b=+1.88이었다. 조직감검사식빵의조직감은완성된식빵을 1시간방냉한뒤 4 4 2 cm로자른후 texture analyzer(model TA-XT2i, Stable Micro Systems, Godalming, UK) 를이용하여 100 mm compression plate를장착하고시료를 2회연속적으로침 Table 2. Operation condition of texture analyzer for white bread with wild grape sourdough Mode Measure force in compression Option Sample size Load cell Pre-test speed Test speed Post-test speed Distance Time Trigger type Data acquisition rate Probe and product data TPA 4 4 2 cm 25 kg 2.0 mm/sec 1.0 mm/sec 1.0 mm/sec 30% 3 sec Auto-1 g 200 pps 70 mm compression plate 입시켰을때나타난 force-time curve로부터경도 (hardness), 부서짐성 (fracturability), 씹힘성 (chewiness) 및복원성 (resilience) 을측정하였으며, 이때의분석조건은 Table 2에나타내었다. 내부표면관찰식빵의내부표면관찰은디지털카메라 (Powershot G- 10, Canon, Tokyo, Japan) 로식빵의내상을검은배경의무대에서플래시가터지지않도록촬영하였다. 이때시료와카메라와의거리, 지면과카메라의높이는동일하게유지시켰다. 관능검사 관능검사는순천대학교식품영양학과조리과학실험실에서학생 58명을대상으로 9점척도법으로소비자검사를동일설문지로실시하였다. 이때품질특성은떫은맛 (astringency), 신맛 (sourness), 단맛 (sweetness) 및거친정도 (coarseness) 및이취 (off-flavor) 를아주심하다 (extreme) 9점, 전혀없다 (none) 1점으로나타내었다. 또한제품의색 (color), 향미 (flavor), 부드러움 (softness) 및전체적인기호도 (overall acceptability) 로서대단히좋아한다 9 점, 좋지도싫지도않다 5점, 대단히싫어한다 1점으로나타내었다. 시료의준비및제시는 1인분분량을 20 g으로정하여세자리난수표로구분하여종이접시위에나열한후제시하였으며, 관능검사에참여한소비자는나이와성별등을기록하고각시료는물컵, 시료를뱉는컵과정수기에서받은물을시료사이에제공하였다. 통계처리모든실험결과는 SPSS 프로그램 (SPSS 12.0 for windows, SPSS Inc., Chicago, IL, USA) 을이용하여일원배치분산분석 (oneway-anova) 을실시하였으며, 각측정평균값간의유의성은 P<0.05 수준으로 Duncan의다중범위시험법을사용하여검증하였다. 실험결과값들사이의상관관계는 Pearson의상관분석을이용하였다.
머루를이용한 Sourdough 식빵개발 1899 결과및고찰머루일반성분머루의일반성분은수분 81.22%, 회분 0.81%, 조지방 0.74%, 조단백질 1.58%, 탄수화물 15.65% 로나타났다. 머루발효액종의특성머루발효액종의 ph, 산도, 당도및알코올함량변화는 Table 3과같다. 발효액종의초기 ph는 3.75로발효 1일차 3.65, 발효 2일 3.40, 3일 3.25, 4일 3.25로발효시간이증가할수록 ph는유의적으로낮아졌으며 (P<0.05), 3일과 4 일은유의적인차이를나타내지않았다 (P<0.05). 초기적정산도는 1.66을나타내었고발효시간이증가할수록증가하는경향을나타냈으며발효 4일차에는 3.31을나타내었다. Kim과 Chun(11) 의연구에건포도발효액의발효기간이증가할수록 ph가낮아지고적정산도가높아졌으며, 블루베리와쌀발효액 (30) 연구에서도같은결과를보였다. 이는여러가지산에영향을받으나주로 acetic acid와 lactic acid 에영향을받는다고한다. 당도는발효 0일차 3.80 o Brix, 발효 1일차에 4.57 o Brix로가장높았으며발효시간이증가 할수록유의적으로낮아졌다 (P<0.05). Kim(31) 은발효 1일차에당도가가장높았는데이는건포도에있는당분이녹아드는결과라고하였으며, 당분을이용해미생물이발효되면서 ph가낮아지고산도가증가하였다고한다. 알코올함량은 1일차에는나타나지않았고발효 2일차에 0.57%, 발효 4일차에는 1.37% 였으며, Fig. 1과같이발효 1일차에 CO 2 가생성되는것을알수있었고발효일수가증가할수록 CO 2 생성이많아졌다. 반죽의 ph와적정산도머루 sourdough를대체한식빵반죽의 ph와적정산도는 Table 4와같다. 대조군은 5.54로유의적으로가장높았으며 (P<0.05), 10% 대체군 5.44, 30% 대체군 5.36, 50% 대체군 4.92 및 70% 대체군 4.70으로대체량이증가할수록유의적으로낮아졌다 (P<0.05). 적정산도는대체군이 1.08 로가장낮았으며머루 sourdough 대체량이증가할수록유의적으로높아졌다 (P<0.05). 식빵반죽의적정 ph는 5.5 6.0으로 (32), ph 5.0 이하에서는효모의작용이활발하지못해가스보유력이약해진다고한다 (33). 본실험에서도 1차발효와 2차발효가진행됨에따라 ph가낮아질것으로 Table 3. Changes in physicochemical properties of fermented wild grape extract during 4 days at 25 C Time (day) 0 1 2 3 4 ph Total titratable acidity (ml) Brix Alcohol contents (%) 3.75±0.02 a 1.66±0.07 d 3.80±0.00 b 0.00±0.00 d 3.65±0.03 b 2.83±0.14 c 4.57±0.06 a 0.00±0.00 d 3.40±0.02 c 3.62±0.10 a 3.13±0.06 c 0.57±0.06 c 3.25±0.01 d 3.27±0.03 b 2.47±0.06 d 1.47±0.06 a 3.25±0.05 d 3.31±0.08 b 1.97±0.06 e 1.37±0.06 b Values are mean±standard deviation (n=3). Means with different letters (a-d) in the same row are significantly different (P<0.05). 0 day 1 day 2 day 4 day Fig. 1. Appearance of fermented wild grape extract during 4 days at 25 C. Table 4. ph and total titratable acidity (TTA) of dough with wild grape sourdough ph TTA (ml) 5.54±0.02 a 1.08±0.02 e 5.44±0.02 b 1.23±0.12 c 5.36±0.02 c 1.30±0.06 c 4.92±0.02 d 1.61±0.07 b 4.70±0.01 e 1.90±0.03 a Values are mean±standard deviation (n=3). Means with different letters (a-e) in the same row are significantly different (P<0.05).
1900 빙동주 김원태 전순실 예상되어 70% 대체군은발효에부정적영향을미칠것으로사료되었다. sourdough는과도한유기산의생성으로글루텐구조와가스포집능력을떨어뜨린다고하였다. 반죽발효팽창력머루 sourdough를대체한식빵반죽의발효팽창률은 Table 5와같다. 발효시간에따른팽창력은대조군이발효시간 90분에서 126.67% 로가장높은값을나타내었고, 10%, 30%, 50% 및 70% 대체군은발효 30분까지는팽창률이변화가없었다. 발효 90분에는 10% 대체군이 20.00% 로유의적으로가장낮았고 (P<0.05) 머루 sourdough 대체량이증가할수록유의적으로높아졌으며 (P<0.05), 50% 와 70% 대체군은각각 49.33%, 53.33% 로 70% 대체군이높게나타났으나유의적인차이는없었다 (P<0.05). 발효팽창력은발효시생성되는 CO 2 가스에영향을받으며 (34), Park 등 (13) 은유산균을첨가한 sourdough의반죽발효는대조군과첨가군간에뚜렷한차이가없다고하였으며또한유산균의종류와관계없이동일한경향으로증가하였다. Sourdough의산도 (acidity) 는빵의부피와노화에영향을주는요소로단백질가수분해효소활성을유도하여글루텐구조의수분을방출시키고 α-amylase 활성을증가시키며전분의수분흡수와효소의활성을변화시킨다고하였다 (35). Park(36) 의연구에서 sourdough 60% 첨가군의발효팽창률이 40% 첨가군보다낮게나타내어일정량이상의 반죽의 2차발효시간머루 sourdough를대체하여제조한식빵반죽의 2차발효시간은 Table 6과같다. 중간발효가끝난뒤반죽의분할량은틀의용적 / 비용적으로계산하여 120 g으로하였다. 그리고발효기에넣고반죽이팬의상단부 1 cm까지올라오는시간을 2차발효시간으로정하였다. 대조군은 81.00분으로가장낮았고대체군들은머루대체량이증가할수록유의적으로낮아졌으며 (P<0.05), 70% 대체군이 168.33분으로나타났다. 식빵의 ph와적정산도머루 sourdough를대체하여제조한식빵의 ph와적정산도는 Table 7과같다. 식빵의 ph는대조군이 5.27로가장낮았으며머루 sourdough 대체량이증가할수록유의적으로낮아졌다 (P<0.05). 적정산도는대조군이 0.95로가장낮았고머루 sourdough 대체량이증가할수록유의적으로높아졌다 (P<0.05). 비용적과굽기손실률머루 sourdough를대체하여제조한식빵의비용적및굽 Table 5. Fermentation power of dough expansion of white bread with wild grape sourdough Wild grape sourdough (%) 0 10 30 50 70 Incubation time (min) 15 30 45 60 75 90 2.67±4.62 NSd 0.00±0.00 c 0.00±0.00 d 0.00±0.00 d 0.00±0.00 d 20.00±6.93 Ad 0.00±0.00 Bc 0.00±0.00 Bd 0.00±0.00 Bd 0.00±0.00 Bd 44.00±0.00 Ac 0.00±0.00 Cc 0.00±0.00 Cd 4.00±4.00 BCd 5.33±4.62 Bd 98.67±16.17 Ab 1.33±2.31 Bc 6.67±4.62 Bc 13.33±6.11 Bc 16.00±6.93 Bc Values are mean±standard deviation (n=3). Means with different small letters in each row are significantly different (P<0.05). Means with different capital letters in each column are significantly different (P<0.05). NS: not significant. 114.67±11.55 Aa 8.00±4.00 Cb 14.67±4.62 Cb 30.67±2.31 Bb 32.00±6.93 Bb 126.67±18.48 Aa 20.00±4.00 Ca 28.00±4.00 Ca 49.33±4.62 Ba 53.33±6.11 Ba Table 6. Second fermentation time of white bread with wild grape sourdough Fermentation time (min) 81.00±6.56 d 213.00±6.56 a 184.67±4.93 b 174.00±5.29 bc 168.33±12.58 c Values are mean±standard deviation (n=3). Means with different letters in the same row are significantly different (P<0.05). Table 7. ph and total titratable acidity (TTA) of white bread with wild grape sourdough ph TTA (ml) 5.27±0.03 a 0.95±0.02 e 5.09±0.02 b 1.12±0.03 d 4.56±0.02 c 1.66±0.04 c 4.28±0.01 d 2.33±0.12 b 4.23±0.01 e 2.55±0.05 a Values are mean±standard deviation (n=3). Means with different letters in the same row are significantly different (P<0.05).
머루를이용한 Sourdough 식빵개발 1901 기손실률은 Table 8과같다. 비용적은 10% 대체군이 4.23 ml/g으로유의적으로가장낮았으며 (P<0.05), 대조군, 50% 및 70% 대체군이유의적으로차이는없었으나 (P< 0.05) 50% 대체군이 4.76 ml/g 으로가장높은값을나타냈다. 굽기손실률은 10% 대체군과 30% 대체군이각각 11.72%, 11.68% 로유의적으로가장낮았고 (P<0.05), 70% 대체군이 12.42% 로가장높은값을나타냈다. 오븐에서굽는과정은식빵의온도가 50 C에이르기전까지는효모의활성이높아져 CO 2 가스발생을증가시키고부피가 1/3 정도크게되는오븐팽창 (oven spring) 이일어나며, 60 C 이상에서효모가불활성화되지만부피는계속팽창하게된다 (37). 발효팽창력은 70% 대체군이가장높았으나계속적인발효과정중유기산의생성으로글루텐구조와 CO 2 가스포집력을약화시켜오븐팽창이낮아진것으로사료된다. 굽기손실률은알코올과이산화탄소와같은휘발성물질과수분이굽는과정중열에의한증발에영향을받으며제품이열과닿는표면적과비례한다고한다 (38,39). 수분함량과수분활성도머루 sourdough를대체하여제조한식빵의수분함량과수분활성도는 Table 9와같다. 수분함량은 10% 대체군이 37.95% 로가장낮았고머루 sourdough 대체량이증가할수록유의적으로증가하여 (P<0.05), Hwang 등 (10) 과 Crowley 등 (40) 의연구에서도대조군에비해 sourdough 첨가군의수분함량이높게나타나본실험과유사한결과를보였다. 이는 sourdough의산 (acid) 에의해 α-amylase가활성화되고전분의수분흡수율변화로인한것으로사료되며 (35), Park(36) 은호밀을이용한 sourdough의발효과정중펜토산의가용화 (solubilization) 로인해수용성펜토산함량이높아지고이는빵의수분흡수율을증가시키며비용적증가로경도가낮아진다고한다 (41). Corsetti 등 (42) 은 sourdough의산으로인해저장기간중식빵내부의수분을다시전체에재분배함으로써신선함을유지하는데긍정적인영향을미친다고한다. 수분활성도는대조군 0.931로가장낮았으나실험군들은 0.931 0.935로유의적인차이를나타내지않았으며 (P<0.05), 수분활성도는미생물이이용할수있는자유수를나타내는지표로수분활성도가높을수록미생물증식에유의해야한다 (11). 색도머루 sourdough를대체하여식빵의색도는 Table 10과같다. 명도는대조군이 58.14로가장높았고머루 sourdough 대체량이증가할수록유의적으로낮아졌다 (P<0.05). 적색도는대조군이 -1.84로가장낮았으며머루 sourdough 대체량이증가할수록유의적으로높아졌고 (P<0.05), 황색도는대체량이증가할수록유의적으로낮아졌다 (P<0.05). Table 8. Specific volume and baking loss of white bread with wild grape sourdough Bread weight (g) Bread volume (ml) Specific volume (ml/g) Baking loss (%) 0 10 30 50 70 105.57±0.61 ab 105.94±0.55 a 105.98±0.67 a 105.11±0.32 b 105.10±0.52 b 497.50±21.27 a 447.92±19.71 c 472.50±16.45 b 500.00±21.11 a 490.83±20.54 a Values are mean±standard deviation (n=12). Means with different letters (a-c) in the same column are significantly different (P<0.05). 4.71±0.21 a 4.23±0.19 c 4.46±0.18 b 4.76±0.20 a 4.67±0.20 a 12.03±0.51 ab 11.72±0.46 b 11.68±0.55 b 12.41±0.27 a 12.42±0.43 a Table 9. Moisture contents and water activity (Aw) of white bread with wild grape sourdough Moisture content (%) Aw 38.40±0.21 c 37.95±0.23 d 0.931±0.006 NS 0.932±0.005 38.74±0.14 b 0.934±0.004 Values are mean±standard deviation (n=9). Means with different letters (a-d) in the same row are significantly different (P<0.05). NS: not significant. 39.06±0.41 a 0.935±0.003 39.12±0.22 a 0.934±0.003 Table 10. Color of white breads with wild grape sourdough Hunter value Crumb L a b 58.14±0.46 a -1.84±0.09 c 10.75±0.29 a 56.69±0.50 b -1.81±0.10 c 9.52±0.33 b 56.30±0.62 b -1.47±0.09 b 9.42±0. b Values are mean±standard deviation (n=12). Means with different letters (a-c) in the same row are significantly different (P<0.05). 55.36±0.31 c -1.21±0.04 a 8.75±0.21 c 55.66±0.70 c -1.16±0.09 a 8.29±0. d
1902 빙동주 김원태 전순실 Table 11. Textural characteristics of white breads with wild grape sourdough Hardness (g) Fracturability (g) Chewiness Resilience 20.06±1.11 cd 1.00±0.09 b 17.4±1.0 c 0.53±0.01 b 37.33±2.76 a 1.22±0.13 a 31.9±3.0 a 0.55±0.01 a 29.12±1.97 b 1.02±0.11 b.8±1.8 b 0.54±0.02 ab Values are mean±standard deviation (n=5). Means with different letters (a-d) in the same row are significantly different (P<0.05). 19.23±1.15 d 1.07±0.11 b 16.2±1.6 c 0.53±0.01 b 22.10±0.75 c 0.98±0.07 b 18.3±0.6 c 0.52±0.02 b 조직감머루 sourdough를대체하여제조한식빵의조직감은 Table 11과같다. 경도는소비자가베이커리제품의품질을인지하는요소중하나 (43) 로부피가작을수록내부구조가작아지고밀집됨에따라경도가높게나타난다 (44). 경도는 10% 대체군이 37.33 g으로가장유의적으로가장높았으며 (P<0.05), 50% 대체군이 19.23 g으로가장낮게나타났다 (P<0.05). 부서짐성은 10% 대체군이 1.22 g으로가장높게나타났고 (P<0.05), 나머지실험군들은 0.98 1.07 g으로유의적인차이를나타내지않았다 (P<0.05). 씹힘성는대조군과 50%, 70% 대체군이각각 17.4, 16.2, 18.3으로유의적으로가장낮게나타났다 (P<0.05). 복원성또한 10% 대체군이 0.55로가장높게나타났으며대조군과 50%, 70% 대체군은 0.52 0.53으로유의적으로가장낮게나타났다 (P<0.05). 내부표면관찰머루 sourdough를대체한제조한식빵의내부표면은 Fig. 2와같다. 머루 sourdough 10% 대체군이부피가가장작았고 sourdough 대체량이증가할수록높아지는것을볼수있었으며, 비용적측정결과와같이 50% 대체군이가장부피가높게나타났다. 관능검사머루 sourdough를대체한제조한식빵의관능검사는 Table 12, 13과같다. 소비자를대상으로실시한특성강도검사에는머루 sourdough 대체한식빵의대표적인관능특성이면서이해가쉬운떫은맛, 신맛, 단맛, 거친정도 4가지특성만을평가하도록하였다. 특성강도검사에서떫은맛은 30% 대체군이 2.12로가장낮았으며실험군들간에는유의적인차이를나타내지않았다 (P<0.05). 신맛은대조군이 1.90으로가장낮았으며머루 sourdough 대체량이증가할수록유의적으로높아졌다 (P<0.05). 단맛은이와반대의결 0% 10% 30% 50% 70% Fig. 2. Photographs of white breads with wild grape sourdough. Table 12. Characteristic intensity rating of white bread with wild grape sourdough Astringency Sourness Sweetness Coarseness 2.16±1.63 NS 1.90±1.33 d 3.83±1.83 a 2.52±1.64 b 2.32±1.65 2.00±1.32 cd 3.67±1.88 ab 3.62±1.81 a 2.12±1.42 2.59±1.59 c 3.36±1.74 ab 3.03±1.94 ab Values are mean±standard deviation (n=58). NS: not significant. Means with different letters (a-d) in the same row are significantly different (P<0.05). 2.40±1.58 3.28±2.08 b 3.40±1.81 ab 2.97±1.79 ab 2.48±1.74 4.05±2.20 a 3.07±1.67 b 2.95±1.74 ab
머루를이용한 Sourdough 식빵개발 1903 Table 13. Consumer acceptance of white bread with wild grape sourdough Color Flavor Softness Overall acceptability 6.48±1.10 a 6.48±1.39 a 6.71±1.28 a 6.67±1.32 a 6.09±1.34 ab 6.02±1.25 ab 5.48±1.57 b 5.76±1.55 b 5.84±1.41 b 5.64±1.48 bc 5.71±1.81 b 5.72±1.75 b Values are mean±standard deviation (n=58). Means with different letters (a-d) in the same row are significantly different (P<0.05). 5.88±1.39 b 5.31±1.44 cd 6.02±1.58 b 5.78±1.74 b 5.67±1.60 b 4.98±1.52 d 5.86±1.57 b 5.19±1.62 b 과를나타냈다. 이는단맛과신맛의상호작용때문이라사료된다. 거친정도는 10% 대체군이 3.62로가장높았으며 (P<0.05), 대조군을제외하고대체군들은머루 sourdough 대체량이증가할수록낮아졌다. 이는소비자의부드러운정도에대한기호도결과와일치하였다. 대부분의특성강도결과들의표준편차가높게나타났는데제품의관능적특성을객관적으로표현하는방법인묘사분석 (descriptive analysis) 은고도로훈련된관능검사요원에의해시행되는것으로제품의관능적특성을객관적으로이해하고자할때사용한다 (45,46). 그러나본실험에서는훈련을거치지않은일반소비자를대상으로특성강도검사를실시하여정량화가제대로이루어지지않은것으로사료되며, 일반적으로소비자에게는특성강도에관한질문을하지않도록권장하고있지만최근일반소비자를대상으로 check-all-thatapply(cata) 법또는 sorting 등의방법이이용되고있다. CATA법은훈련된패널이아닌일반소비자가설문지에관능적조항수에제한을받지않고다지선택할수있는형식으로제품에대한감각적특성을빠르고쉽게얻을수있어이러한방법등을접목하여기호도와특성강도에관한의견을평가하고있는추세이다 (47,48). 색에대한기호도는대조군이 6.48로가장높았고 30%, 50% 및 70% 대체군들은유의적인차이가없었다 (P<0.05). Katina 등 (6) 은밀가루의회분함량과발효시간은관능검사에미치는중요한요소이며, 톡쏘는듯하며자극취가나지않는 sourdough는전체적인맛, 후미, 굽는향등을향상시키며, Lactobacillus brevis를스타터로한 sourdough 20% 첨가는자극취가과도하게나지않아신선한풍미를감소시키지않았다고한다. 향미에대한기호도는머루 sourdough 대체량이증가할수록낮아졌다 (P<0.05). 부드러운정도에대한기호도는대조군이가장높았고, 대체군들은유의적인차이가없었으나 (P<0.05) 50% 대체군이 6.02로가장높은값을나타내어조직감의경도측정과유사한결과를나타내었다. 전체적인기호도는대조군이 6.67로가장높은값을나타냈고 (P< 0.05), 대체군의기호도는 5.19 5.78로유의적인차이는없었으나 (P<0.05) 50% 대체군이 5.78로가장높게나타났다. 이결과를종합하면식빵의품질특성과소비자기호도등을고려하여머루 sourdough 50% 대체군이최적배합비로결정되었다. 요 본연구에서는머루를이용한 sourdough를제조하고머루 sourdough 10%, 30%, 50% 및 70% 를대체한식빵의이화학적특성과관능검사를실시하였다. 25 C에서발효한머루액종의 ph는발효시간이증가할수록 ph는유의적으로낮아졌으며, 적정산도는증가하는경향을나타냈다. 당도는발효 1일차에 4.57 o Brix로가장높았고발효시간이증가할수록유의적으로낮아졌으며 (P<0.05), 알코올함량은 1일차에는나타나지않았고 4일차에서 1.37% 를나타냈다. 완성된발효액에밀가루를첨가하여 20 C에서 36시간발효하여 sourdough를제조하였다. 제조된머루 sourdough 10%, 30%, 50% 및 70% 로대체하여식빵을제조하였다. 식빵반죽의 ph는 sourdough 대체량이증가할수록낮아졌으며적정산도는유의적으로증가하였다. 발효시간에따른발효팽창력은 10% 대체군이 20.00% 로유의적으로가장낮았으며 (P<0.05), sourdough 첨가량이증가할수록유의적으로높아졌다 (P<0.05). 반죽의 2차발효시간에서대체군들은머루대체량이증가할수록유의적으로낮아졌다 (P<0.05). 식빵의비용적은 50% 대체군이 4.76 ml/g으로가장높은값을나타냈다. 수분함량은머루 sourdough 대체량이증가할수록유의적으로증가하였고 (P<0.05), 수분활성도는실험군들간에유의적인차이를나타내지않았다 (P<0.05). 조직감에서경도는 50% 대체군이 19.23 g으로가장낮게나타났다. 기호도검사결과색, 향미, 부드러운정도및전체적인기호도는 sourdough 대체량이증가할수록유의적으로감소하였다. 따라서식빵의품질특성과소비자기호도등을고려할때머루 sourdough 50% 대체군이최적배합비로결정되었다. 약 REFERENCES 1. http://www.newsam.co.kr/news/article.html?no=1417 (accessed Jun 2014). 2. Chung HC. 2008. Properties of sourdough-added bread. Korean J Food Sci Technol 40: 643-648. 3. Corsetti A, Settanni L. 2007. Lactobacilli in sourdough fermentation. Food Res Int 40: 539-558. 4. Lee JH, Kwak EJ, Lee YS. 2008. Quality characteristics of sourdough breads added with red koji rice sourdough powder. J Korean Soc Food Sci Nutr 37: 333-341. 5. Marklinder I, Johanssona L, Haglunda Å, Nagel-Held B,
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