224 Nippon Shokuhin Kagaku Kogaku Kaishi Vol. // No. /. - (**2) 22 * * E# ect of Modified Wheat Starches on the Textural Properties of Baked Products such as Cookies Atsuko Higo and Yoshiko Wada* Bunkyo University Women s College ++** Namegaya Chigasaki Kanagawa /-2//* * Kanto Gakuin University + /* + Mutuura higashi Kanazawa-ku Yokohama Kanagawa -02/*- The textural properties of baked products such as cookies were studied by using the modified wheat starches with di# ering gelatinized characteristics. ( + ) The baked products containing gelatinized starches were hard and became harder when absorbed moisture was increased. () Based on a high positive correlation between the breaking properties and the starch gelatinization values a paste material was suggested to be a principal factor for hardening. (-) After moisture absorption the hardening point of gelatinized samples was shifted to higher humidity and the hardening region was widened. (.) Water activity of hardened samples was clearly lower. Increasing of starch-gel and restricting water are assumed to be the important factors leading to hardening of baked products. (Received Oct. ++ **1 ; Accepted Feb. + **2) Keywords : modified wheat starches textural properties baked products gelatinization moisture absorption : + + - /. W a+ : +** g 0 g /-2//* ++** * -02/*- + /* + +** g -* g Corresponding authorhigo@shonan.bunkyo.ac.jp -* g +* g Wa W Table + W + : W : W a : W a :
23 : 225 Table + Basic properties of modified starches and properties of baked products Samples of modified starches Ingredient Baking properties of cookies Samples of Ingredient modified starches Baking properties of cookies Water Thickness Viscosity Water Thickness Viscosity (g) (mm) (mpas) (g) (mm) (mpas) W: +* 240 W : * 24* Un-modified wheat starch -* 241./ Gelatinized after cross-linked -* 14 1** /* 242 +** Forming low viscosity paste /* 142..** +** 242 +** 242 W- + : +* 24/ W : +* 242 Cross-linked for later gela- -* 240 - Etherificated starch -* 243.** tinization /* 240 1/ More gelatinization type /* 34. 2** Faster retro gradation in the paste +** 24. +** 340 W- : +* 240 W : +* 242 Partial acetylated starch -* 243 0 Etherificated and cross-linked -* 34 -.** Gelatinization type /* 242 ++/ More gelatinization type /* +*4 00** +** 240 +** +-4/ Other contents are flour +** g sugar -* g and butter -* g. The flour +** g is mixed with +** g of modified starches and 0 g of gluten powder. a a-+ a- Fig. + The case of forming for test samples of water +** /flower +** and the baked products * g -* /* +** g. +** +** Fig. +. +. -* +* SN-**2 PLZ +2* * /* +** g +.* +2* / + - : + -* + - RX-+0** * g./.* ml + + mm ++ *** rpm +. *** rpm - ** mmmin - mm.* TV-* H BM
226 // / **2 / 24 Fig. Typical load-time curves for various baked samples / upper figure : maximum stress ( +* N/m ) 0 - lower figure : total energy ( +* J/m ) n/ or over 2 H/.* * rpm -* /* Table + W W+ +..* W Wa Wa+ Wa -* /* / -- - ao /0 Wao Sigma Amyloglucosidase A- 1.* PH../ +** Fig. ao - 0 GSI AW-CCP / +** + / +** +* Wa /* * -* /* +** W +* * +** W Wa+ Wa +** Wa Table + +** W W+ -* /* W awa+ Wa
25 : 227 Fig. - Water sorption isotherms of storage samples R.H..- Wa+ Wa R.H. /0 0 -* /* WW+ W Wa +* Wa Wa+ -* /* +** +* -* - /* +** W R.H. -.- 02 2* Wa- - * Wa R..- 22 22 31 H. 1. 0 ++ -.- /0 02 2* 22 31 W W+ W Wa +* -* Wa+ Wa -* +** Fig. - R.H. 1. 031 g +** g W -* -. 1 +3.* /*... +.* +** /. 0.* W a -*.... *./ /* /...* +** 0.* -./ a R.H. 22 Fig. / +. + R.H. 22 R.H. 1. 031 +* -* /* +** W Fig.. *2/. +/.. 3+. Wa- *11. -/.
228 // / **2 / 26 Fig.. Changes of maximum stress and total energy after moisture sorption 1. 2 +.. 1 +* -* +** 3 +/ Fig.. -* /* R.H. 0231 / R.H. 10. - Fig. 0 R.H. 10. - Fig. 0. + R.H. 0231 -* /* /* W W+ W Wa Wa+ ao -* W a +.. +... +. -. /. Fig. 0 /*./ 00** mpas Table + /* W W + -.. 0. 3 00* nm O.D. W Wa W a+ W a. /....-. -2. 0.. *0..0. ao +/ 12 Fig. 0
27 : 229 -* /* r *. 0** *. 3+ r *. 1+2 *. 22/ 0 1 NMR 23 Aw *1. *13. Fig. / Typical load-time curves for samples stored Fig. - R.H. 1* 13 under R.H. 22 moisture g +** g / upper figure : maximum stress ( +* N/m ) R.H. 1/ W -* 3. + 0 - lower figure : total energy ( +* J/m ) +. +** +*. 2 +.. 2 W a -* +*. +.. +** +.. +1.* Wa Fig. 1 R.H. 22 ++ + 3/* 0 - +* Jm O.D. *. ++ /. + Fig. 2 Wa +* +** +*.* +/.* g+** g r *..* Aw+** -* W 1+ Wa - W - 2- Wa 012* +** Wa /. 1. 0 Fig. 1 r *. 2 *. 32/ 1 Table - /. + +/* +* Nm r *./. 0 r *. 023 *. 310 Fig.. +* -* /* +** W -* /* R.H. 1. 0-0.* 0. 1 ++.* +.. 2 g+** g W a 2. +1.. R.H. 0231 +.* -./ g+** g Table r *. 021 *. 3+3-0.* -./ g+** g. +-.* -./ g +** g +* ++
230 // / **2 / 28 Fig. 0 Textural properties of storage samples under low or high moisture and gelatinization characteristics of samples Fig. 1 Correlation between total energy of samples stored at 22 moisture and starch solubility of samples 0 + +- +. W+ Wa Wa+ Wa
29 : 231 +2 +3 W * +/ +0 + - -* +2 +1 Table Correlation between maximum stress of water -* /* samples stored under low or high moisture and the gelatinization characteristics Low moisture High moisture Starch solubility y242x143 y+ x.4 r *43+3 r *423. Swelling capacity y+ x-. y-+ x+*/ r *42-0 r *423 Viscosity y+0 x+0 y-3 x// r *42+* r *413- a-starch degree y*40/ x*43 y+41 x+3 r *4021 r *42. Fig. 2 Correlation between water activity and water content of samples absorbed at relative humidity Table - Water contents and humidity at hardening point and hardening ratio of maximum stress after moisture sorption Samples Hardening point Samples Hardening point Modified starch Water Water R.H. Modified starch Water Water R.H. Ratio (g) (g/ +** g DM) ( ) (g) (g/ +** g DM) ( ) Ratio W +* 04* - +4+ Wa +* -* 041.- +4- -* +*4-02 +40 /* ++4* 02 +42 /* +-4* 2* 4- +** +.42 2* 4+ +** +24* 2* 4/ W-+ +* 04. +4* Wa-+ +* 24/ /0 +4 -* 14/ /0 +4+ -* +142 22 4+ /* +*42 02 +4- /* +042 2* 41 +** +.40 2* +42 +** +241 2* 41 W- +* 04 - +4 Wa- +* 24.- +4* -* +*41 02 +4/ -* +14. 22 4+ /* +-40 2* 41 /* +4* 2* 42 +** +.42 2* 41 +** -4/ 31-4- Detail definitions of the samples are listed at Table +. Ratio of maximum stress at hardening point/mean at R.H. 140-
232 // / **2 / 30. **. 0-2 // 0- +33+ 1 J.A. Troller and J.H.B. Christian pp. 223* **+ 2 NMR / -. /00 /1/ +32-3 a -/ +12 +2- +32. +* Cadden A.M. Moisture sorption characteristics of several food fibers J. Food Sci. /- ++/* ++// ( +32/ ). ++ Rockland L.B. Water activity and storage stability Food Technology - ++ + ( +303). + 1-1 +/3 +03 **. +- /+ 0-10.* a **. +. /. 2 **1 +/ -1 20/ 21* +320 +0 -. 1-12 +32- +1 +/ +33 +2 2. - +32+ +3 -+ +3 - +32/ * pp. /00 +33. + + pp. +/ ***.+ J-13-2+ Augus /* +3 1 +333 *** -.3 11+ 12+ ** Netsu - Bussei +1 ++. +1 **- / 31-*/ **/.. /. /- 0* **1 pp. -+ -2 *** / +3 +* ++ * +