Changes in Microbial Counts, Enzyme Activity and Quality of Foxtail Millet Takju Treated with High Hydrostatic Pressure during Storage

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(1)KOREAN J. FOOD SCI. TECHNOL. Vol. 36, No. 2, pp. 233~238 (2004). ©The Korean Society of Food Science and Technology. .{ ¾Ò §&ç"~ &Ë 7 b>, Î²W 5 ®îæz ªçn*Á²ãÁÏÆ1Á;'*1ÁÖ2 Bv ®", 1ãöv «¦, 2®~£®n*Ó ®>". Changes in Microbial Counts, Enzyme Activity and Quality of Foxtail Millet Takju Treated with High Hydrostatic Pressure during Storage Sangbin Lim*, Mi-Kyung Jwa, Chulkyoon Mok1, Young-Seo Park1, and Gun-Jo Woo2 Department of Food Science and Engineering, Cheju National University 1 Division of Biotechnology, Kyungwon University 2 Division of Food Microbiology, Korea Food and Drug Administration Foxtail Millet Takju was treated with heat (65oC/30 min) (HT) or high hydrostatic pressure (27oC/400 MPa/10 min) (PT), and changes in microbial count, enzyme activity, and quality were determined during 30-day storage at 10 and 25oC. Total viable cellcount remained constant, while lactic acid bacteria and yeast were not detected in HT and PT Takjus. Relative activities of α-amylase in PT Takju significantly increased by 169.7% at 3 days storage, then decreased to 137.7 and 68.7% at 10 and 25oC, respectively, at 30 days. Relative activities of glucoamylase in HT Takju showed reversible change, and were 36.5 and 54.3% at 10 and 25oC, respectively, at 30 days storage. Activities in PT Takju increased with storage period, 158.2% at 30 days storage at 10oC. Titratable acidity in untreated Takju increased, while those in HT and PT Takjus remained almost constant during 30 days storage. Reducing sugar content in untreated Takju showed no change, while that in HT Takju increased gradually, reaching 2.9% at 30 days, whereas that in PT increased sharply after 3 days, reaching 4.8% at 30 days. Sensory evaluation showed sourness and bitterness were low, and sweetness and overall acceptance were high in PT Takju after 30 days storage at 10oC. Key words: Takju, high hydrostatic pressure, pasteurization, enzyme inactivation, quality change. B. . ¢z& ÚJÚ ^B6j n ® (5,6). ¢ Oæ~V *~ ç"¢ &~ &ËWf ËÒ > ®b¾, ~ B *, ; k(zëÚ)~ W, æï, [ªÒ bÒ' Wç~ æz ~ ç®Wj &~Êº ^B6j n ® (3,7). V¢B ç"~ æîö &~º "º bj ÒÊB ®î~ &~¢ ²z > ®º ¾Ò O»~ BB jº~ . .{ &VFf j ÒÏ~æ p bj Ú > ®bæ îÚ ®&»b V&¢ Îb ® . { ~ öBº ¦b& *Úº OËb z>w /ê>æ ² >W Ö" NÖ~ 2Zº /ê>æò FÖ" >² Öf n;zB . V¢B .{ ¾ÒVFf ® ¾~ ® î &~¢ ²z~B bj Ú~¾ Î²¢ ®W zÒ > ®bæ(8), ç"f ?f *Û®~ W Ëç j * îÚ ;b ÏF > ®j © . ç"~ FÛ"; 7 º~º bö ~ ®îæz¢ Û B~V *~Bº, ç"¢ B çê <Ö" ÎÎ¢ Ò B <Öö ~ ÖW" ÎÎö ~ r BÎ¢ ;æ Ò jº& ® . -æò Ú>Ú ®º Î² 7 ß® glucoamylase~ ºWj FæÒ > ® &Ë 7 Wj / êB B®~ ®îj FæÒ > ®j ©b V&B . V¢B öBº ®î~ æz¢ ²z~B &ËW. ç"º ÖÒ¾¢ F~ *Û"B JÑÿn ";rò Bê ï" '·B~ j ~B ÖÒ"~ ö æ & 'Ëj öz (1). "öê ®~ ç"~ ²jïf 1970j& 7> ê æ³'b 6²~ ®º, º "~~. ·zf ²j¶~ V^ê æzº b, ç" ¶Ú& &æ ®º &ËW, ²zW ~ ®ïö V (2,3). ç"öº Aspergillus, Rhizopus, Mucor³~ Gf Saccharomyces, Pichia, Candida, Torulopsis, Hansenula³~ ÎÎf Bacillus, Micrococcus, Aerobacter, Pseudomonas³~ ^ G~ ® (4). V¢B ZÚ ç"º FÛ"; 7ö bö ~~ º~º ~~ æ³' BÎ ~ ². " þ " ç&'b Ã&~² >º ®î~. *Corresponding author : Sangbin Lim, Department of Food Science and Engineering, Cheju National University, Ara il-dong, Jeju-si, Jeju-do 690-756, Korea Tel: 82-64-754-3617 Fax: 82-64-755-3601 E-mail: [email protected] 233.

(2) ®"²æ B 36 ² B 2 ^ (2004). 234. ®º "³ "~¢ B~V *~, ·öò §&j Ï~ B ç"¢ &çb jÚ» .{¾Ò»j 'Ï~, &ËNê 5 &ËV*ö V b>, Î²W 5 ®îæz¢ G;~ ç"~ &ËW ÃêÎ"¢ ¦;~& .. Òò 5 O» Òò §&ç"º J·(B")öB B jÚ ç"¢ «~ ÒÏ~& . &¾Ò §&ç"¢ 125 mL Ò*j2÷ö jÖ 65oC~ water bath(MC-31, JeioTech Co., Korea)öB 30ª* & ê N öB ï'~& . {¾Ò þö ÒÏ .{V(MFP-7000, Mitsubishi Heavy Industries Co., Japan)º ÚÏ' 600 mL, b& 125 mL Ò *j2÷ö §&ç"¢ jò V& Ú&æ p² &/. r, ÷j Òö2 jªb vß Ë ê Ã~>& j òê {ÏVö I ;>{²* bÊÊj çßB &{ ~& . .{¾Òº çN(27oC)/400 MPa/10ªöB ~& . ¾ÒNêº ¾Ò{KöB ¾Ò* ÿn ªî {ÏV Ú ¦~ Nê¢ G;~ ï 8b ¾æÚî .. ê ²jB NaOH~ ·b¦V ';Öê(%<Ö)¢ êÖ~ & (12). ~ö §&ç" 10 mL¢ 100 mL C ê "æ(Toyo No. 2) " r 1 mLö DNS £ 3 mL¢ & ê 5ª 7û~ çN ï' ê 550 nmöB 7ê¢ G;~ glucose ~ &Fj Ï~ ~Ö~& (11). Ë¦Ò §&ç"~ &Ë' ®îf ®" Ò 20«j N6 F;~ ~ ;ê(, , )f «' V^êö &~ 96 j6»b ~& (13). r j6V&f j " ;~ (± ): 96, Ûb ;~ (± ): 76, '~ (± æê ¾~æê p ): 56, Ûb £~ (¾~ ): 36, j" £~ (¾~ ): 16î . &Ë¦Ò Ö"º SAS¢ ÒÏ~ Duncan~ 7º*¦;j ~ F~N¢ ªC~& (14).. Ö 5 V b>~ æz §&ç"¢ (65oC/30ª) $º .{(27oC/400 MPa/10ª)b ¾Ò ê 10oCf 25oCöB 30¢* &Ë~º ÿn ¢>^. &Ë þ Z¾Ò §&ç", ¾Ò §&ç", .{¾Ò §&ç"¢ 10oCf 25oCöB 30¢* &Ë~B 3¢î ò¢ ~ b>, Î²W 5 ®îßWj G;~& . b ¦Ò ç"~ bf &ÂV·»(9)b ^>, <Ö>, Î Î>¢ G;~& . ^f &ÂVæöB, <Öf 0.133% ~ .Öj &~ « pH¢ 5.5 ; Rogosa SL agar V æöB 37oC/72* V·~&, ÎÎº YM agar VæöB 25oC/72* V·~& . ÷£> 30-100B ï6j ~ ÷ £>¢ G;~ CV>¢ ~ *¦b b>¢ Ö Â~& . 4² > G;~ ï~& . Î²W /; Î²f òö 0.5% NaCl Ïj &~ NöB 30ª v> ê "æ(Toyo No. 2) "~ B~& (10). αAmylase~ Wf 1% *ªÏ 1 mLö Î² 1 mL¢ &~ 30oC/30ª* >wÊ 1 M .Ö 10 mLf 1/3000 N ºJ z Ï 10 mL¢ & ê 660 nmöB 7ê¢ G;~&b, blank OD8~ 10%j 6²Êº ©j 1 unit ¾æÚî (9). Glucoamylase~ Wf 0.5% *ªÏ 1 mLö Î² 1 mL ¢ &~ 30oC/30ª* >wÊ dinitrosalicylic acid reagent (DNS) 3 mL¢ & ê 535 nmöB 7ê¢ G;~&b, Î ² 1 mL& 1 mg~ glucosej FÒÒ r~ Î²ïj 1 unit ¾æÚî (9,11). 8f 2² > G;~ ï~& . ';Öê §&ç" 10 mLö 1% phenolphthalein Ïj &~ ';. Fig. 1. Changes in total bacteria counts of Foxtail Millet Takju treated with heat or high hydrostatic pressure during storage at 10oC and 25oC..

(3) .{ §&ç"~ &Ë 7 b>, Î²W 5 ®îæz. 235. Fig. 2. Changes in lactic acid bacteria counts of Foxtail Millet Takju treated with heat or high hydrostatic pressure during storage at 10oC and 25oC.. Fig. 3. Changes in yeast counts of Foxtail Millet Takju treated with heat or high hydrostatic pressure during storage at 10oC and 25oC.. >~ æz¢ G; Ö"º Fig. 1" ?~ . Z¾Ò~ ¢ >^>º &ËNê 10oCöB &Ë.Vf jv~ &Ë 30 ¢ êö l log cycle 6² >, 25oCöBº 3 log cycle 6² ~ 10oC 25oCöB 6² z . Mok (2)ê 4oC f 25oCöB jÚ£"¢ &Ë~º ÿn >º 6²~& º, º &ËV* 7ö FVÖ~ Wö V '·ª~ & ~ ^~ WË &¢ A~V r^ ©b º;~ ®. . Þ ¾Òf .{¾Òº Î &ËNêöB &Ë V*ö V ¢>^>~ Nº ~ ìî . $º . {¾Ò ê º~º bf ¶;W¾ ¢¦ ²·W ©b º;>î . $º .{b ¾Ò §&ç"~ &ËV* 7 <Ö >~ æzº Fig. 2f ?~ . Z¾Ò §&ç"~ .V <Ö >º 7.0Ü107 CFU/mLîæò $º .{¾Òö ~B j*® Ò>î . &ËV*ö V <Ö~ æzº Z¾Ò ~ ãÖ æz& ìîb, $º .{b ¾Ò § &ç"~ <Öf j*® ÒB ê &ËV* 30¢ ÿn ¦ Â>æ pj :²ç n;Wj ¾æÚî . $º .{b ¾Ò §&ç"~ &ËV* 7 ÎÎ> ~ æzº Fig. 3" ?~ . Z¾Ò §&ç"~ ÎÎ>º 9.5Ü 106 CFU/mLîæò $º .{ ¾Òö ~~ j*® Ò >î . &Ë 30¢ ÿn $º .{¾Òº <Ö~ ãÖf îR&æ ÎÎ& ¦Â>æ pj :²ç n;Wj. ¾æÚî . ¾ Z¾Ò ãÖöº &ËNê 10oCöBº &ËV* ÿn ÎÎ>~ æz& 'îb¾, 25oCöBº ê³' b 6²~ &Ë 30¢öº 1.9Ü103 CFU/mL 3 log cycle 6²>î . Î²W~ æz *ª~ zö 7º j ~º α-amylase~ &ËV*ö V ç&W~ æzº Fig. 4f ?~ . §&ç"¢ ¾Ò çê α-amylase~ ç&Wf 21.8% 78.2%& ®Wz>î b¾, .{ ¾Ò ò~ ç&Wf Z¾Òf jÝ~&. . &ËV*ö V ç&W~ æzº 10oCöB &Ë~º ÿ n Z¾Òf .{¾Òº &Ë 3¢ö '' 161.0%f 169.7% /Ï® Ã&~&b¾, ê 6²~V ·~ & Ë 6¢ êöº ~ ¢; ãËj ¾æÚîb &Ë 30¢ö '' 135.3%f 137.7%î . Þ ¾Òº &ËV* ÿn ç&W~ æz& ~ ìî . &ËNê 25oCöB Z¾Ò f .{¾Òº 10oCöBf ? &Ë 3¢ö Î²W / Ï~² Ã&~&æò ê 6²~&b &Ë 30¢ö '' 47.9%f 68.7%î . Þ ¾Òº 10oCöBf îR&æ W~ æz& ~ ìî . Weemaes (15)f Bacillus subtilis¦V~ α-amylasej jÏÏöB .{ ¾Ò ê 022oCöB 6* &Ë~º ÿn Î²Wf Ã&~&º, N öB &NöB Ã&N z ¸~ ~& . $.

(4) 236. ®"²æ B 36 ² B 2 ^ (2004). Fig. 4. Changes in L-amylase activity of Foxtail Millet Takju treated with heat or high hydrostatic pressure during storage at 10oC and 25oC.. Fig. 5. Changes in glucoamylase activity of Foxtail Millet Takju treated with heat or high hydrostatic pressure during storage at 10oC and 25oC.. Laidlerf Bunting(16)f Î²¢ 70oC çöB ¾Ò~ j& ' ®Wz& ¢ÚÂ ~& . zB *ªj glucose &>ª~º Î² glucoamylase ~ &ËV*ö V ç&W~ æzº Fig. 5f ?~ . ¾ Ò §&ç"~ glucoamylase~ ç&Wf 17.1% ¾Òö ~~ 82.9%& ®WzB >, .{ ¾Ò ò~ W f Z¾Òf jÝ~& . 10oCöB &Ë~º ÿn ¾Ò ~ ç&Wf BB® Ã&~ &Ë 30¢ êöº 36.5% & ' æz¢ ¾æÚî . Z¾Òf .{¾Òº 10oCö B &Ë 30¢ ê ç&W '' 119.2%f 158.2%, .{ ¾Ò& &ËV* 7 Ã& &Ë . &ËNê 25oCöB º ¾Ò~ ç&W 10oC z ô Ã&~&b & Ë 30¢ö 54.3% &Ë.Vö j~ &' W~ Ã& ¢ & . ¾ Z¾Òº &ËV* ÿn W ² 6 ²~ &Ë 30¢ö 89.9%î . .{ ¾Ò §& ç"º 25oCöB &Ë 12¢ö W 159.3% Ã&~& & 6²~ &b &Ë 30¢öº 114.9%î .. ~ æN& ê¯> ®º ©b º;B . Þ $º . {¾Ò~ ';Öêº &ËV* ÿn æz& ìîº, j §&ç"¢ $º .{¾Ò~ 10oCöB &ËV * 7 Ö~ Wj Oæ > ®î . º Tanakaf Hatanaka (17) ºÞ¢ 10-20oCöB 300 MPa 10ª ¾Ò Ö" FÛ 7ö ¢Ú¾º ÖWj Oæ > ®î º f ¢ ~~º ©b, $º .{¾Òö ~~ <Ö~ ®W zö V~º ©b º;B . &ËNê 25oCöB Z¾Ò ~ ';Öêº &Ë 3¢ ê /Ï® Ã&~ &Ë 30¢ö 1.12% î . ¾Òº 10oCöBf îR&æ &Ë 7 ~ æz & ìîæò, .{¾Òº &ËV* ÿn .O Ã&~º *çj & . &ËV* 7 §&ç"~ " &ê& ®º ~ö ï~ æzº Fig. 7" ?~ . 10oCöB &ËV* 7 Z¾Ò~ ~ ö ïf æz& ~ ìº >, ¾Òº ê³'b Ã&~ &Ë 30¢ö 2.9%î . Þ .{¾Òº &Ë 3¢ ê¦V /Ï~² Ã&~&b &Ë 30¢ êöº ~ö ï 4.8%î . ~ö ï~ Ã&º glucoamylase~ W" &N ®bæ glucoamylase~ W ¸j> ~ö ï ¸j ©b V&B (18). ¯, glucoamylaseº ¾ Òö ~~ ®Wz>îæò .{ ¾Òö ~Bº W J®J Ã&>îb, 10oCöB &ËV* ÿn Î²W ê³'b Ã&>îbæ ~ö ïê Ã&B ©b º. ®îæz $º .{b ¾Ò §&ç"~ &ËV* 7 ';Ö ê~ æzº Fig. 6" ?~ . &ËNê 10oCöB Z¾Ò~ ';Öêº &Ë.Vö 0.70%öB &Ë 30¢ö 1.02% &Ë V*ö V¢ Ã&~º *çj ºbö ~~ ç".

(5) .{ §&ç"~ &Ë 7 b>, Î²W 5 ®îæz. 237. Fig. 6. Changes in titratable acidity of Foxtail Millet Takju treated with heat or high hydrostatic pressure during storage at 10oC and 25oC.. Fig. 7. Changes in reducing sugar of Foxtail Millet Takju treated with heat or high hydrostatic pressure during stored at 10oC and 25oC.. ;B . ² & .{¾Ò~ ~ö ï ¸f ©f . {¾Òö ~ §&ç"~ ÎÎ& >î &Ë 7öê ¦ Â>æ pj ÎÎö ~ ª~ ²j& ìîV r^ . Þ Z¾Ò ãÖ &Ë 7 glucoamylase W ² Ã&~ &æò ~ö ï ¢; ©f º~º ÎÎö ~~ ª ²j>îV r^ ©b º;B (6). &ËNê 25oCö Bº &ËV* 7 Z¾Ò~ ~ö ïf 10oCf îR&æ ~ æz& ìî . ¾ ¾Òº glucoamylase W ~ Ã&f z®Ú ~ö ïê &Ë 30¢ö 5.68% /Ï® Ã&~& . .{¾Ò~ ~ö ïê glucoamylase W ~ æzf FÒ~² &Ë 12¢ö 5.42% Ã&~& & 6² ~ &Ë 30¢öº 3.03%î . ç~ Ö"öB 10oCf 25oCöB &Ë~º ÿn $º .. {b ¾Ò §&ç"º ÎÎ~ Ò ~ ~ö ² j>æ p~j öò jî¢, glucoamylase~ W Ã& ~ö ï Ã&>îbæ, V ç"~ êBÎö ~ j j~V ~ j Î&¢ ~º ^B¢ Ö > ®j © b V&B (6). Þ $º .{b ¾Ò §&ç"~ ~ö ïf 10oC 25oCöB z Ã&~&º, æ¾ ~ ö ï~ Ã&º §&ç"~ proteaseö ~ W>º j Ö" z>wj ¢bB .æ~ öbîj W > ®b æ 25oCöB 10oCöB &Ë~º © :²ç~ . $º .{b ¾Ò §&ç"¢ 10oCf 25oCöB 30 ¢* &Ë ê~ &Ë' ßWf Table 1" ?~ . f 10oC öB &Ë $º .{¾Ò& &Ë ¸~b, Z¾Ò º Î &ËNêöB F~'b &Ë Ôf 8j & . . Table 1. Sensory properties of Foxtail Millet Takju treated with high hydrostatic pressure after storage at 10oC and 25oC for 30 days Storage temperature o. Untreated Sweetness Sourness Bitterness Overall acceptance 1). 25oC. 10 C. Sensory attribute 2.5bc1) 7.8a 6.4ab 3.2bc. Heat treated. Pressure treated. Untreated. Heat treated. Pressure treated. 4.2a 5.8b 4.6c 4.7a. 4.2a 4.2c 4.6c 4.7a. 1.5c 8.2a 7.0a 2.0c. 3.4ab 4.7c 5.0bc 4.4ab. 1.8c 7.8a 6.6a 2.2c. The same superscripts in the same row are not significantly different at 5% level by Duncan's multiple range test..

(6) ®"²æ B 36 ² B 2 ^ (2004). 238. º 10oCöB &ËV* ÿn $º .{¾Ò~ ~ö ï Ã& >, Z¾Òº 6²~&V r^ ©b º; B . §&ç"~ f Z¾Òf 25oCöB &Ë .{ ¾Ò& &Ë ;~&º, º ';Öê~ æzf ¢~~º ©b &ËV* 7 ';Öê& Ã&~º &ËNê 25oCöB ~ Z¾Ò& &Ë ;~& . ~ ãÖ " j Ý ãËj Z¾Òf 25oCöB &Ë .{¾Ò & &Ë ¸~b, ; 10oCöB &Ë $º . {¾Ò& F~'b &Ë Ô~ . Þ «' V^êº 10oCöB &Ë $º .{¾Ò& &Ë ¸f >, Z ¾Òf ß® 25oCöB &Ë .{¾Ò& &Ë Ô~º , º ~ &Ë¦Ò Ö"f ¢~~º ©b, §&ç" ~ V^êº &Ë' ßW 7 ö ~~ &Ë 'Ëj A º ©b º;B .. º. £. §&ç"¢ (65oC/30ª) $º .{(27oC/400 MPa/10ª)b ¾Ò ê 10oCf 25oCöB &ËV*ö V b>, Î ²W 5 ®îæz¢ G;~& . $º .{¾Ò~ ¢ >^>º Î &ËNêöB &ËV*ö V¢ æz& ì îb, <Ö" ÎÎº j*® ÒB ê &Ë 30¢ ÿn ¦ Â>æ p~ . α-Amylase~ ç&Wf .{¾ÒöB 10oC öB &Ë 3¢ö 169.7% /Ï® Ã&~& & &Ë 30¢ö 137.7% 6²~&b, 25oCöBº &Ë 30¢ö 68.7% & ËV*ö V¢ BB® 6²>º ãËj & . ¾Òº & ËV* ÿn ~ æz ì Ôf Wj Fæ~& . ¾Ò ~ glucoamylase ç&Wf 10oCf 25oCöB &' æz ¢ ¾æÚÚ &Ë 30¢ö '' 36.5%f 54.3%îæò, . {¾Òº 10oCöB &ËV*ö V¢ W Ã&~ &Ë 30¢ö 158.2%î . Z¾Ò~ ';Öêº &ËV* ÿn Ã& >, $º .{¾Òº æz& ~ ìî . 10oC öB &ËV* 7 Z¾Ò~ ~ö ïf ~ æz& ì º >, ¾Òº &ËV* 7 ê³'b Ã&~ &Ë 30¢öº 2.9%î, .{¾Òº &Ë 3¢ ê¦V /Ï® Ã&~º *çj &b &Ë 30¢öº 4.8%î . &Ë¦ Ò Ö" 10oCöB 30¢ &Ë .{¾Ò& " ' " «' V^ê& ¸j &Ë Ö> ®îj ¾ æÚî .. 6Ò~ º "Ò ß;V.(98-04-02-01-01-3) æ öb >¯>îb, ö 6Òãî .. ^. ò. 1. Lee KB, Kim JH. Studies on radiation preservation of fermented Korean rice-wine. Korean J. Microbiol. 7: 45-56 (1969) 2. Mok CK, Lee JY, Chang HG. Quality changes of non-sterilized Yakju during storage and its shelf-life estimation. Food Eng. Prog. 1: 192-197 (1997) 3. Lee CH, Tae WT, Kim, GM, Lee HD. Studies on the pasteurization conditions of Takju. Korean J. Food Sci. Technol. 23: 44-51 (1991) 4. Lee ZS, Rhee TW. Studies on the microflora of Takju brewing. Korean J. Microbiol. 8: 116-133 (1970) 5. Lee CH, Lee HD, Kim JY, Kim KM. Sensory quality attributes of Takju and their changes during pasteurization. Korean J. Diet. Cult. 4: 405-410 (1989) 6. Bae SM, Kim HJ, Oh TK, Kho YH. Preservation of Takju by pasteurization. Korean J. Appl. Microbiol. Biotech. 18: 322-325 (1990) 7. Mok CK, Lee JY, Chang HG. Optimization of heat sterilization condition for Yakju. Food Eng. Prog. 2: 137-143 (1998) 8. Lee DU, Park J, Kang JI, Yeo IH. Effect of high pressure on the shelf-life and sensory characteristics of angelica keiskei juice. Korean J. Food Sci. Technol. 28: 105-108 (1996) 9. Park JM, Oh HI. Changes in microflora and enzyme activities of traditional Kochujang meju during fermentation. Korean J. Food Sci. Technol. 27: 56-62 (1995) 10. Hong SW, Hah YC, Yoon KS. On the changes of amylase activity and saccharifying ability in Takjoo mashes during the process of brewing. Korean J. Microbiol. 6: 141-146 (1968) 11. Miller GL. Use of dinitrosalicylic acid reagent for determination of reducing sugar. Anal. Chem. 31: 426-428 (1959) 12. Kang MY, Park YS, Mok CK, Chang HG. Improvement of shelflife of Yakju by membrane filtration. Korean J. Food Sci. Technol. 30: 1134-1139 (1998) 13. Stone H, Sidel JL. Sensory Evaluation Practices. 2nd ed. Academic Press. New York, NY, USA. pp. 84-87 (1993) 14. SAS Institute Inc. SAS User's Guide. Statistical Analysis Systems Institute, Cary, NC, USA (1996) 15. Weemaes C, De Cordt S, Goossens K, Ludikhuyze L, Hendrickx M, Herenans K, Tobback P. High pressure, thermal, and combined pressure-temperature stabilities of α-amylases from Bacillus Species. Biotechnol. Bioeng. 50: 49-56 (1996) 16. Laidler KJ, Bunting PS. General kinetic principles. pp. 35-67. In: The Chemical Kinetics of Enzymic Action. Leidler KJ (ed). Clarendon Press, Oxford, UK (1973) 17. Tanaka T, Hatanaka K. Application of hydrostatic pressure to yoghurt to prevent its after-acidfication. Nippon Shokuhin Kogyo Gakkaishi 39: 173-177 (1992) 18. Hara A, Nagahama G, Ohbayashi A, Hayashi R. Effects of high pressure on inactivation of enzymes and microorganisms in nonpasteurized rice wine. J. Agric. Chem. Soc. Jpn. 64: 1025-1030 (1990) (2003j 10ú 25¢ 7>; 2004j 3ú 5¢ j).

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