Korean J Food Cook Sci Vol. 33, No. 6, pp. 636~642 (2017) pissn 2287-1780 eissn 2287-1772 https://doi.org/10.9724/kfcs.2017.33.6.636 보이차젤리의품질특성및항산화효과 정지승 정하숙 덕성여자대학교자연과학대학식품영양학과 Physicochemical Characteristics and Antioxidant Activities of Pu-erh Tea Jellies Ji Seung Jeong Ha Sook Chung Department of Food and Nutrition, Duksung Women's University, Seoul 01369, Korea Abstract Purpose: The aim of our study was to investigate the quality characteristics and antioxidant activities of pu-erh tea jellies. Methods: Jellies were prepared with different amounts of pu-erh tea (0, 5, 10, 20, and 40%). The ph, sugar content, color, hardness,total phenol compounds, anti-oxidative activities, and sensory properties of pu-erh tea jellies were determined. Results: As a result, the ph, sugar content, and hardness of pu-erh tea jellies were significantly reduced with increasing levels of pu-erh tea (p<0.05). For color values, as the content of pu-erh tea increased, L-values of the jellies significantly decreased while a- and b-values significantly increased (p<0.05). Total phenolic compounds and anti-oxidative activities increased with increasing concentration of pu-erh tea (p<0.05). Sensory properties in terms of color, flavor, bitterness, chewiness, and overall preference showed the highest scores in jelly with 20% pu-erh tea. Conclusion: In conclusion, jelly with 20% pu-erh tea is recommended to take advantage of its functional properties with consumer acceptability. Key words: pu-erh tea, Camellia sinensis L., functional jelly, quality characteristics, antioxidant Ⅰ. 서론 생활수준의향상과건강에대한관심이높아지면서, 건강기능성이우수한식품에대한수요와선호도가증가하여생리활성이높은천연소재를첨가한제품개발에대한연구가꾸준히계속되고있다 (Hwang YK 등 2001). 젤리는겔 (gel) 상식품으로당류와겔화제를혼합하여농축 성형하여굳힌후건조하여제조되는반고체식품 (Kim AJ 등 2007) 으로감촉이부드럽고씹고삼키기용이하여유아나노인용기능성식품제형으로주목받고있다. 젤리는수분을 20% 내외로함유하여젤라틴, 펙틴, 한천등수분결합이가능한겔화제의종류와부재료에따라다양한조직감을가진제품을기대할수있다 (Oh HJ 등 2013). 전분젤리는조직이단단하고, 한천과펙틴젤리는잘끊어지며씹힘성이약한반면, 젤라틴젤리는씹힘성은좋지만잘끊기지않는다는특징이있다 (Kim HJ 등 2015). 최근까지감귤 (Jeong JS & Kim ML 2008), 흑마늘농축액 (Kim AJ & Rho JO 2011), 숙지황농축액 (Kim NY 등 2011), 인디언시금치열매착즙액 (Moon JH 등 2016), 유자 (Jo HY 등 2015) 등다양한식품소재를활용한젤리등이보고된바있으며, 이와는다른종류의겔화제와부재료를첨가하여젤리의물리적, 관능적특성을향상시킨연구가지속적으로진행되고있다. 중국운남지역의대엽종차나무 (Camellia sinensis L.) 의찻잎을건조시켜제조되는보이차 (Pu-erh tea) 는생산과제조공정에있어녹차, 홍차등과구분된다. 따뜻하고습한환경에장시간노출시켜 Aspergillus 속과 Penicillium 속등의미생물이분비하는효소에의해발효가진행되어후발효차로분류되며 (Park SH 등 2009), 찻잎은주로흑갈색을띄고탕색은등황색이며특유의숙성된향을지니고있다 (Son GM 등 2005). 보이차는제다법에따라 Corresponding author: Ha Sook Chung, Department of Food and Nutrition, Duksung Women's University, 33, Samyng-ro 144-gil, Dobong-gu, Seoul 01369, Korea ORCID: http://orcid.org/0000-0001-9983-6489 Tel: +82-2-901-8593, Fax: +82-2-901-8593, E-mail:hasook@duksung.ac.kr http://www.ekfcs.org 2017 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 (http://creative-commons.org/lice nses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Korean J Food Cook Sci 보이차젤리의품질특성및항산화효과 637 크게생차 ( 生茶 ) 와숙차 ( 熟茶 ) 로구분되며, 생차는살청 ( 殺靑, 푸른찻잎의색을제거하는과정 ), 유념 ( 柔捻, 손으로찻잎을비비는공정 ) 의과정을거쳐햇볕에건조한쇄청모차를통풍이잘되고건조한곳에서자연건조시켜제조하며 (Abe M 등 2008), 숙차는쇄청모차를습한곳에보관하여발효속도를증가시켜비교적단시간에발효시키는악퇴 ( 渥堆, 고온다습한곳에서찻잎을발효시키는공정 ) 과정을거쳐제조되며 (Choi SH 2016), 본실험에서는보이차생차를시료로사용하였다. 보이차는인체에유익한아미노산, 비타민, 알칼로이드, 폴리페놀, 탄닌등의기능성화합물을다량함유하고있으며, 이화합물은은항염증, 항암 (Hayakawa S 등 2001), 항산화 (Duh PD 등 2004), 항알러지 (Weisburger JH 1999) 등다양한생리활성효과가있는것으로알려져있다 (Kim HJ 등 2010). 뿐만아니라, 본실험실에서는보이차가 UVB 로염증을유발시킨 HaCaT 세포를보호하며, 인체대장암세포주인 HCT116 사멸효과가높음을확인하였다 (Guon TE 등 2016). 일반적으로보이차는저장기간이오래될수록품질과맛이우수하다고알려져있는데, 이는미생물에의한발효중떫고쓴맛이있는 catechin 이산화되어떫은맛이감소되기때문이다 (Kim IY 등 2013). 또한보이차의후발효과정중 catechin, gallic acid, theaflavin, thearubigin, theabrownine, caffeine, flavonoids 등의함량이변화되어보이차고유의향, 맛, 색의품질을나타낸다 (Lv HP 등 2013). 따라서이번연구에서는선행연구를근거로항산화, 항암효능이입증된보이차를다양한편이식품가공에이용하기위한연구의일환으로, 보이생차를첨가하여보이차젤리를제조하고시료인보이차대체비율에보이차젤리의물리화학적특성및관능적품질특성을평가한후, 항산화효과규명을통해부가가치가우수한기능성젤리개발을위한실험적기초자료를확립하고자한다. 1. 재료및시약 Ⅱ. 재료및방법 실험에사용된보이차생차는 2012 년중국윈난성 (Menghai Tea Factory, Yunnan, China) 에서생산된것을구입하여블랜더 (HR1372, Philips, Shanghai, China) 로분쇄후냉장보관하여사용하였다. 백설탕 (CJ CheilJedang, Seoul, Korea), 젤라틴 (Eselnara, Daegu, Korea) 은시중에서구입하여제조하였다. 항산화활성실험에사용한 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino bis(3-ethyl benzothiazoline-6-sulphonic acid) (ABTS), Folin-ciocalteu s phenol reagent, gallic acid, 2,4,6-tris (2-pyridyl)-1,3,5-triazine(TPTZ), 6-hydroxy-2,5,7,8- tetramethlychroman-2-carboxylic acid(trolox), ethanol, sodium Table 1. Ingredient composition of jelly incorporated with different levels of pu-erh tea Ingredient (g) Contents of pu-erh tea (%) 0 5 10 20 40 Pu-erh tea 0 20 40 80 160 Gelatin 15 15 15 15 15 Sugar 50 50 50 50 50 Water 400 380 360 320 240 carbonate, FRAP 용액은모두 Sigma 사 (St. Louis, MO, USA) 의특급시약을사용하였다. 2. 젤리제조 실험에사용된젤리는 Hwang ES & Thi ND(2015) 의방법을참고하여여러차례예비실험을거친후재료배합비율을 Table 1 과같이결정하였다. 보이차가첨가되지않은젤리를대조군으로하고, 첨가하는물의중량을기준으로보이차를 5, 10, 20, 40%(w/w) 첨가하여제조한젤리를실험군으로설정하였다. 보이차를우리는방법은예비실험을통해최적의방법을설정하였으며, Kim EJ 등 (2015) 의방법을참조하였다. 즉, 증류수 1,150 g 을끓인후보이차잎 15 g 을넣고 10 분간우려낸후여과하여실험재료로사용하였다. 젤리는증류수에보이차와설탕, 젤라틴을넣고 80 o C 가될때까지가열한후, 설탕과젤라틴이완전히용해되면상온에서식혀직사각형틀 (190 70 65 mm) 에넣고수분이증발되지않도록랩을씌워 4 o C 냉장고에서 3 시간동안성형한후, 실험에사용하였다. 3. ph 및당도측정 보이차젤리의 ph 와당도측정을위한시료는젤리 10 g 에증류수 90 ml 를넣고균질화시킨후 Whatman No.1 여과지로여과하여준비하였으며, ph 는 ph meter(bp3001, Trans Instruments, Jalan, Singapore) 를, 당도는식품당도계 (HI96801, HANNA Instruments, Inc., Woonsocket, RI, USA) 를이용하여측정하였다. 모든실험은각각 3 회반복측정하였으며, 평균값과표준편차로표시하였다. 4. 색도및경도측정색도측정은색도계 (HI96801, HANNA Instruments, Inc., Woonsocket, RI, USA) 로젤리표면의 L값 (Lightness), a 값 (redness), b값 (yellowness) 을각각 3회반복측정하여평균값과표준편차로나타내었다. 사용된표준백색판은 L=93.88, a=-0.32, b=3.37이었다. 젤리의경도는 Mo EK 등 (2007) 의방법을참고하였고, texture analyzer(ta Plus, Lloyd Instrument Ltd., West Sussex, UK) 로측정하였다. 시료는가로, 세로, 높이를각각 30 mm, 30 mm, 20 mm http://www.ekfcs.org 2017; 33(6):636-642
638 정지승 정하숙 Korean J Food Cook Sci 로준비하여측정하였고 3 mm 의원형탐침 (probe) 을사용하였다. Depression limit 는 8 mm, test speed 는 5 mm/sec, trigger force 는 0.3 N 로설정하였으며, 실험결과는 5 회반복측정하여평균값과표준편차로나타내었다. 5. 총페놀성화합물함량측정 총페놀성화합물함량은 phosphomolybdic acid 와반응하여청색을나타내는원리를이용한 Richard-Forget FC 등 (1992) 의 Folin-Denis 방법으로측정하였다. 젤리 80 g 을잘게부순후중량대비 10 배 (w/v) 의 70% ethanol 을첨가하고실온에서 72 시간침지후여과하여시료액으로사용하였다. 젤리추출물 50 μl 와 Folin-Ciocalteu s phenol reagent 50 μl 를첨가하여혼합한후 3 분간실온에서반응시킨후, 10% sodium carbonate 용액 150 μl 를첨가하여암실에서 1 시간동안방치하여 ELISA reader(spectramax, Molecular Devices, LLC, Sunnyvale, CA, USA) 를이용하여 760 nm 에서흡광도를측정하였다. Gallic acid 를이용하여검량선을작성하였고총페놀성화합물함량은건조시료중량당 mg gallic acid equivalent(gae/g dry weight, DW) 로표시하였다. 6. 항산화활성측정 DPPH free radical 소거활성은 Blois MS(1958) 방법으로측정하였다. 젤리 80 g 을잘게부순후중량대비 10 배 (w/v) 의 70% ethanol 을첨가하고실온에서 72 시간침지후여과하여시료액으로사용하였다. 젤리추출물 100 μl 에 0.2 mm DPPH 용액 100 μl 를가하고실온에서 30 분동안반응시킨후 ELISA reader(molecular Devices, LLC) 를이용하여 515 nm 에서흡광도를측정하여 free radical 소거능을계산하였다. ABTS 라디칼소거활성은 Fellegrini N 등 (1999) 의방법으로측정하였다. 보이차젤리추출물 10 μl 에 ABTS solution 190 μl 을가하여암소에서 10 분반응시킨후 ELISA reader(molecular Devices) 를이용하여 734 nm 에서흡광도를측정하고라디칼소거활성을계산하였다. FRAP 환원능측정은 Benzie IFF & Strain JJ(1996) 방법을참고하였다. 젤리추출물 10 μl 와 FRAP 용액 190 μl 를혼합하여 30 분간반응시킨후 ELISA reader(molecular Devices) 를이용하여 595 nm 에서흡광도를측정하였다. 시료의 FRAP 환원능은 Trolox 로표준곡선을작성하여 Trolox equivalent antioxidant activity(mg TEAC/g dry sample) 로표시하였다. 7. 관능검사 관능검사는덕성여자대학교식품영양학전공대학원생중훈련된 10 명의패널을선정하여실험목적과평가방법및측정항목에대해인지될수있도록충분히설명한뒤 실시하였다. 평가항목은젤리의색 (color), 향미 (flavor), 쓴맛 (bitterness), 단맛 (sweetness), 부드러운정도 (softness), 씹힘성 (chewiness), 전반적인기호도 (overall preference) 이며 9 점척도 (1, 대단히싫다 9, 대단히좋다 ) 를사용하여평가하였다. 각시료는 3 자리난수표를이용하여구분하였다. 8. 통계처리 모든실험은 3 회이상반복하였고, 실험결과는 SPSS Statistics(ver. 24.0, IBM Corp., Armonk, NY, USA) 를이용하여각실험군의평균과표준편차로계산하고 ANOVA 분석후 p<0.05 수준에서 Duncan's multiple range test 를실시하여대조군과처리군간의유의성을검정하였다. 1. ph 및당도 Ⅲ. 결과및고찰 보이차가첨가되지않은젤리 ( 대조군 ) 의 ph 는 5.22 로확인되었고보이차첨가량이증가할수록젤리의 ph 가유의적으로감소하였으며, 보이차 40% 첨가군에서 ph 4.87 을나타내었다 (p<0.05)(table 2). 이는보이차발효중미생물대사과정에서생성되는유기산인 oxalic acid, citric acid, quinic acid 등이포함되어 (Horie H 등 1998) 보이차함량이증가할수록젤리의 ph 가감소한것으로사료된다. 또한이번실험에서, 아로니아에함유된유기산에의해젤리 ph 가유의적으로감소한연구 (Joo SY 등 2015) 와동일한결과가나타났으며, 이는보이차첨가량이증가함에따라보이차에함유된유기산에의해젤리의 ph 가감소한것으로추정된다 (Data not shown). 보이차가첨가되지않은대조군젤리의당도는 1.13 o Brix 로나타났다. 보이차첨가에따라젤리의당도가감소하였으나 20% 첨가군까지는유의적이지않았으며, 40% 첨가군의당도는 0.97 o Brix 로다른첨가군에비해유의적으로감소하였다 (p<0.05)(table 2). 돌나물즙 (Mo EK 등 2007) 젤리연구에서는젤리제조시일정한양의당이다량첨가되어부재료인돌나물즙을소량넣는것은젤리의당도에유의적인영향을미치지않는것으로설명한바있다. 본연구에서는보이차첨가량이 5, 10, 20, 40% 증가할수록젤리의당도가감소하였으며, 보이차 0, 5, 10, 20% 첨가군에서는유의적인결과를나타내지않았는데, 이는상대적으로보이차당도가낮기때문인것으로생각된다 (0.23 o Brix, Data not shown). 2. 색도및경도보이차젤리의밝기를나타내는 L값은대조군젤리가 35.96으로가장높았으며, 보이차첨가량이증가함에따라 L값이 32.17에서 28.33으로유의적으로감소하였다 2017; 33(6):636-642 http://www.ekfcs.org
Korean J Food Cook Sci 보이차젤리의품질특성및항산화효과 639 Table 2. Quality characteristics of jelly incorporated with different levels of pu-erh tea Properties Contents of pu-erh tea (%, w/w) 0 5 10 20 40 ph 5.22±0.14 1)a 5.06±0.01 b 5.01±0.02 bc 4.92±0.04 cd 4.87±0.01 d o Brix 1.13±0.06 a 1.10±0 a 1.07±0.06 a 1.03±0.06 ab 0.97±0.06 b L-value 35.96±1.26 a 32.17±2.56 b 30.47±0.31 bc 29.52±1.06 bc 28.33±0.80 c a-value 0.26±0.04 e 0.56±0.02 d 0.68±0.05 c 1.11±0.08 b 1.26±0.05 a b-value 1.02±0.07 e 3.07±0.09 d 5.24±0.03 c 6.21±0.27 b 7.85±0.48 a Hardness (N) 1.81±0.12 a 1.78±0.11 a 1.70±0.09 ab 1.62±0.06 bc 1.56±0.04 c 1) All values are mean±sd (n=3). a-e Means in a row different superscripts are significantly different at the p<0.05 level by Duncan s multiple range test. (p<0.05). 적색도를나타내는 a 값은대조군젤리가 0.26 으로가장낮았고첨가량이증가함에따라유의적으로증가하였다 (p<0.05). 또한황색도를나타내는 b 값도대조군젤리가 1.02 로가장낮았고첨가량이증가함에따라 7.85 까지유의적으로증가하였다 (p<0.05)(table 2). 보이차는미생물발효가행해지는퇴적공정동안차잎에존재하는일부식물성색소성분들이중합되어오렌지색의 theaflavin, 적색의 thearubigin, 갈색의 theabrownin 으로변환되어수색 ( 水色 ) 에영향을주며 (Kosińska A & Andlauer W 2013), 이번실험에서는보이차함량이증가할수록젤리의 L 값이감소하고적색도를나타내는 a 값과황색도를나타내는 b 값이증가하는것으로확인되었다. 대조군젤리의경도는 1.81 N 으로가장높게나타났고보이차첨가량이 5, 10, 20, 40% 증가함에따라경도가 1.78, 1.70, 1.62, 1.56 N 으로감소하는경향을나타내었다 (p<0.05)(table 2). 이러한결과는보이차첨가량이증가할수록젤리의유기산함량증가로 ph 가감소하고, 감소된 ph 가젤리의경도에영향을미친것으로사료된다. Gel 의최적강도는 ph 5 에서 10 사이이며, 산은 gel 의단백질분자의결합을가수분해하여 gel 을약화시킨다. 따라서 ph 가낮은부재료를사용하여젤리를제조하여 ph 가 4 이하가되면경도가낮은부드러운 gel 을생성하거나그이하일경우, gel 의형성을방해할수있다 (Brown A 2011). 이는흑마늘첨가량이증가할수록경도가감소 (Lee JY 등 2010) 한경우와유사한양상을나타내었으며, Kim HJ 등 (2015) 의생맥산농축액젤리연구에서도생맥산으로인해젤리의보습성이높아져단단하지않은질감을갖게되는것으로보고한바있다. 따라서젤리의물리적특성은첨가된시료에함유된성분과연관성이큰것으로추정된다. 3. 총페놀성화합물함량 대조군젤리의총페놀성화합물함량은 11.58 mg GAE/g 으로가장낮았으며, 보이차첨가량이 5, 10, 20, 40% 증가할수록보이차젤리의총페놀함량이각각 Fig. 1. Total phenolic compound contents of jelly incorporated with different levels of pu-erh tea. All values are mean±sd (n=3). a-e Different letters on the bars are significantly different at the p<0.05 level by Duncan's multiple range test. 12.69, 16.52, 18.48, 27.98 mg GAE/g 으로유의적으로증가하였다 (p<0.05)(fig. 1). 수산기를가지고있는방향족화합물인페놀성화합물은식물계에다량함유되어있으며, 고유의색과맛을부여하고항산화반응에관여하여 free radical 을환원시켜인체내노화, 질병예방에효과가있는것으로알려져있다 (Cho JW 등 2012). 따라서젤리제조시첨가하는보이차함량이증가할수록보이차에함유된페놀성화합물의양도증가하여총페놀성화합물함량에영향을준것으로사료되며, 이와같은결과는아로니아과즙첨가량에따른젤리연구 (Hwang ES & Thi ND 2015) 에서클로로겐산, 바닐산, 루틴수화물등과같은페놀성화합물이풍부한아로니아과즙첨가량이증가할수록젤리의총폴리페놀함량이비례하여증가한것과동일한결과를나타내었다. 4. 항산화활성 보이차젤리의 DPPH free radical 소거능은대조군젤리 http://www.ekfcs.org 2017; 33(6):636-642
640 정지승 정하숙 Korean J Food Cook Sci Fig. 2. DPPH and ABTS radical scavenging activity of jelly incorporated with different levels of pu-erh tea. All values are mean±sd (n=3). a-d Different letters on the bars are significantly different at the p<0.05 level by Duncan's multiple range test. 가 3.74% 로가장낮은소거능을보였으며, 보이차첨가량이 5, 10, 20, 40% 증가할수록소거능이각각 6.71, 17.45, 23.30 과 42.76% 로유의적으로증가하였다 (p<0.05)(fig. 2). 이는식물체총폴리페놀함량과항산화작용사이에밀접한상관관계가있어폴리페놀함량이높을수록항산화작용이높았다고보고한연구 (Kim HK 등 2002, Seog HM 등 2002) 와일치하는것으로확인되었다. ABTS 는산화유도물질인 potassium persulfate 와의반응으로생성된청록색의 ABTS 양이온이항산화성물질에의해제거되어탈색되는원리를이용하여항산화력을측정하는방법이며다양한산성환경에서도사용할수있어여러연구에서활용되고있다 (Shalaby EA & Shanab SMM 2013). 보이차젤리의 ABTS radical 소거능은대조군이 2.87% 로가장낮았으며, 보이차첨가량이 5, 10, 20, 40% 로증가할수록소거능이각각 5.96, 9.65, 15.09, 24.91% 로유의적으로증가하는것이확인되었다 (p<0.05)(fig. 2). 이는차추출 Fig. 3. FRAP assay of jelly incorporated with different levels of pu-erh tea. All values are mean±sd (n=3). a-e Different letters on the bars are significantly different at the p<0.05 level by Duncan's multiple range test. 물에함유된 catechins, polyphenols, thearubigin, theabrownin, gallic acid 등의주요항산화성분 (Oi Y 등 2012) 이보이차젤리의항산화효과에영향을미친것으로사료된다. FRAP 환원능은낮은 ph 에서환원제에의해산화반응의촉매작용을감소시켜 ferric ion 복합체가파란색의 ferrous ion 으로환원되는원리를이용한방법 (Kim MS 등 2011) 으로, 대조군젤리의 FRAP 환원능이 2.81 mg TEAC/g 으로가장낮았으며, 보이차첨가량이 5, 10, 20, 40% 로증가함에따라각각 7.57, 15.67, 27.10, 58.52 mg TEAC/g 까지유의적으로증가하였다 (p<0.05)(fig. 3). 이러한결과는 FRAP 값과총폴리페놀함량과의상관관계를규명한연구 (Benzie IFF & Szeto YT 1999) 와동일한실험결과를보여주었으며, 보이차추출물에함유된다양한종류의페놀성화합물이젤리의항산화활성에주요인자로작용하고있음을알수있다. Table 3. Sensory evaluation data of jelly incorporated with different levels of pu-erh tea Properties Contents pu-erh tea (%, w/w) 0 5 10 20 40 Color 4.70±2.50 b 5.30±1.89 b 6.20±1.32 ab 7.20±1.14 a 4.70±2.26 b Flavor 3.20±2.35 c 4.10±1.60 bc 5.40±2.12 ab 6.40±2.17 a 5.90±2.13 ab Bitterness 4.70±2.50 c 5.60±1.43 abc 6.70±1.49 ab 6.9±1.45 a 5.0±2.40 bc Sweetness 4.80±2.62 NS 5.00±2.00 NS 6.40±1.78 NS 6.80±1.69 NS 5.50±2.55 NS Softness 6.10±2.38 NS 6.10±1.91 NS 6.70±1.83 NS 7.20±1.69 NS 6.0±2.36 NS Chewiness 4.60±2.07 b 5.70±2.00 ab 6.80±1.62 a 7.20±1.99 a 6.00±2.26 ab Overall preference 3.60±2.22 c 4.20±1.93 bc 5.90±1.97 ab 7.10±1.20 a 6.00±2.54 ab a-e Means in a row by different superscripts are significantly different at the p<0.05 level by Duncan s multiple range test. NS Not significantly different at p<0.05. 2017; 33(6):636-642 http://www.ekfcs.org
Korean J Food Cook Sci 보이차젤리의품질특성및항산화효과 641 5. 관능검사 보이차젤리의기호도를평가한관능검사결과는 Table 3 과같다. 색, 향미, 쓴맛, 씹힘성은보이차가 0-20% 까지첨가된경우에선호도가증가하였으며, 보이차 40% 첨가군에서는감소하였다. 이는일정농도의보이차첨가가젤리의색, 향미, 맛, 조직감에긍정적인영향을주는것으로확인되었다. 또한젤리의단맛과부드러운정도의경우, 20% 첨가군이기호도가가장높았지만시료간의유의적인차이는보이지않았다. 결론적으로, 보이차를 20% 첨가하여제조한젤리의경우, 건강효능과기호성이우수한최적의기능성제품으로사료된다. Ⅳ. 요약및결론 본연구는대표적후발효차인보이차 (Pu-erh tea) 젤리의이화학적특성및항산화효과를관찰하여기능성젤리로의이용가능성을알아보고자시도되었다. 보이차젤리의 ph, 경도및당도는보이차첨가량이 0, 5, 10, 20, 40% 증가함에따라유의적으로감소하였다 (p<0.05). 보이차젤리의색도는첨가량이증가함에따라 L 값이유의적으로감소하는 (p<0.05) 반면, a, b 값은유의적으로증가하였다 (p<0.05). 보이차젤리의총페놀성화합물함량, DPPH free radical, ABTS radical 소거능및 FRAP 환원능은보이차첨가량이 0% 에서 40% 로증가할수록모두유의적으로증가하였다 (p<0.05). 관능검사결과, 색, 향, 맛, 부드러운정도, 씹힘성및전체적인기호도가보이차 20% 첨가군이가장높게평가되었다. 이상의결과를근거로, 보이차를첨가하여젤리를제조할경우, 젤리의이화학적품질과항산화특성및관능적만족도등을고려하여 20% 첨가가가장적절한것으로판단된다. Conflict of Interest No potential conflict of interest relevant to this article was reported. Acknowledgments This research was supported by College of Natural Sciences, Duksung Women s University, Seoul, Korea in 2016. References Abe M, Takaoka N, Idemoto Y, Takagi C, Imai T, Nakasaki K. 2008. Characteristic fungi observed in the fermentation process for Puer tea. Int J Food Microbiol 124(2):199-203. Benzie IFF, Strain JJ. 1996. The ferric reducing ability of plasma (FRAP) as a measure of antioxidant power : The FRAP assay. Anal Biochem 239(1):70-76. Benzie IFF, Szeto YT. 1999. Total antioxidant capacity of teas by the ferric reducing/antioxidant power assay. J Agric Food Chem 47(2):633-636. Blois MS. 1958. Antioxidant determinations by the use of a stable free radical. Nature 181(4617):1199-1200. Brown A. 2011 Understanding food: Principles and preparation. Cengage Learning, Stamford, CT, USA. pp 340-341. Cho JW, An TH, Lee SY, Park KW. 2012. Determination of total content of phenolic compounds in Chinese matrimony vine s accessions. Korean J Crop Sci 57(4):409-417. Choi SH. 2016. Volatile flavor components in raw pu-erh tea and fermented pu-erh tea (Camellia sinensis L.). J Korean Tea Soc 22(2):50-54. Duh PD, Yen GC, Yen WJ, Wang BS, Chang LW. 2004. Effects of pu-erh tea on oxidative damage and nitric oxide scavenging. J Agric Food Chem 52(26):8169-8176. Fellegrini N, Ke R, Yang M, Rice-Evans C. 1999. Screening of dietary carotenoids and carotenoid-rich fruit extracts for antioxidant activities applying 2,2'-azinobis (3-ethylenbenzothiazoline-6-sulfonic acid) radical cation decolorization assay. Method Enzymol 299:379-389. Guon TE, Jeong JS, Chung HS. 2016. Effect of pu-erh tea on UVB-induced oxidative damage in human HaCaT and cytotoxicity in HCT116 human colon cancer cells. J Korean Tea Soc 22(4):115-121. Hayakawa S, Kimura T, Saeki K, Koyama Y, Aoyagi Y, Noro T, Nakamura Y, Isemura M. 2001. Apoptosis-inducing activity of high molecular weight fractions of tea extracts. Biosci Biotechnol Biochem 65(2):459-462. Horie H, Yamauchi Y, Kohata K. 1998. Analysis of organic anions in tea infusions using capillary electrophoresis. J Chromatogr A 817(1):139-144. Hwang ES, Thi ND. 2015. Quality characteristics of jelly containing aronia (Aronia melanocarpa) juice. Korean J Food Sci Technol 47(6):738-743. Hwang YK, Hyun YH, Lee YS. 2001. Study on the characteristics of bread with green tea powder. Korean J Food Nutr 14(4):311-316. Jeong JS, Kim ML. 2008. Quality evaluation of citrus jelly prepared using concentrated citrus juice. Korean J Food Cook Sci 24(2):174-181. Jo HY, Kang TY, Jung JH, Ko SH. 2015. Effect of citron pomace oleoresin and sugar contents on the quality of citron jelly. Food Eng Prog 19(3):187-192. Joo SY, Ryu HS, Choi HY. 2015. Quality characteristics of jelly added with aronia (Aronia melancocarpa) juices. Korean J Food Cook Sci 31(4):456-464. Kim AJ, Rho JO. 2011. The quality characteristics of jelly added with black garlic concentrate. Korean J Human Ecol 20(2):467-473. http://www.ekfcs.org 2017; 33(6):636-642
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