枣果特点:
l 色、香、味、营养物质
l 季节性强
l 不易储运
l 种植面积大，产量高，加工需求显现
2. 试验方法
l FD:冷阱温度-55 oC，压强15 Pa，面板加热温度为25 oC，冷冻干制时间为48 h；
l AD:50 oC、60 oC、70 oC，风速0.75 m/s；
l SD:常温下晾晒；
l MD: 45 W、65 W、95 W、135 W，物料质量450 g；
l 联合干燥优化：不同水分转换点选择。
表3-1 热风干燥中不同薄层干燥模型的拟合结果
|
No. |
T(ºC) |
Constants |
R2 |
χ2 |
RMSE |
|||
|
1 |
50 |
k=0.02357 |
|
|
|
0.9937 |
4.4×10-4 |
0.0207 |
|
60 |
k=0.04557 |
|
|
|
0.9949 |
3.8×10-4 |
0.0190 |
|
|
70 |
k=0.07492 |
|
|
|
0.9923 |
6.3×10-4 |
0.0241 |
|
|
2 |
50 |
k=0.01439 |
n=1.13249 |
|
|
0.9996 |
3.0×10-5 |
0.0053 |
|
60 |
k=0.03131 |
n=1.12192 |
|
|
0.9997 |
3.0×10-5 |
0.0052 |
|
|
70 |
k=0.05025 |
n=1.15611 |
|
|
0.9992 |
7.0×10-5 |
0.0077 |
|
|
3 |
50 |
k=0.65137 |
n=0.03619 |
|
|
0.9937 |
4.5×10-4 |
0.0207 |
|
60 |
k=0.957 |
n=0.04761 |
|
|
0.9949 |
4.0×10-4 |
0.0191 |
|
|
70 |
k=1.16126 |
n=0.06451 |
|
|
0.9923 |
6.8×10-4 |
0.0240 |
|
|
4 |
50 |
k=0.02461 |
a=1.03715 |
|
|
0.9963 |
2.7×10-4 |
0.0160 |
|
60 |
k=0.04725 |
a=1.0317 |
|
|
0.9968 |
2.5×10-4 |
0.0151 |
|
|
70 |
k=0.07767 |
a=1.03123 |
|
|
0.9943 |
5.0×10-4 |
0.0206 |
|
|
5 |
50 |
k=0.01971 |
a=1.13091 |
c=-0.11693 |
|
0.9989 |
8.0×10-5 |
0.0086 |
|
60 |
k=0.03847 |
a=1.11857 |
c=-0.10711 |
|
0.9992 |
7.0×10-5 |
0.0078 |
|
|
70 |
k=0.05731 |
a=1.18251 |
c=-0.17505 |
|
0.9988 |
1.2×10-4 |
0.0096 |
|
|
6 |
50 |
k0=0.02461 |
k1=0.02461 |
a=0.51859 |
b=0.51859 |
0.9963 |
2.8×10-4 |
0.0159 |
|
60 |
k0=0.04725 |
k1=0.04725 |
a=0.51583 |
b=0.51583 |
0.9968 |
2.8×10-4 |
0.0151 |
|
|
70 |
k0=0.07767 |
k1=0.07767 |
a=0.51561 |
b=0.51561 |
0.9968 |
2.8×10-4 |
0.0139 |
|
|
7 |
50 |
k=0.03112 |
a=1.651 |
|
|
0.9998 |
2.0×10-5 |
0.0044 |
|
60 |
k=0.05933 |
a=1.63196 |
|
|
0.9998 |
2.0×10-5 |
0.0043 |
|
|
70 |
k=0.10107 |
a=1.68409 |
|
|
0.9995 |
5.0×10-5 |
0.0065 |
|
|
8 |
50 |
a=-0.01951 |
b=0.00011 |
|
|
0.9999 |
6.1×10-6 |
0.0024 |
|
60 |
a=-0.03768 |
b=0.00041 |
|
|
1.0000 |
3.1×10-6 |
0.0017 |
|
|
70 |
a=0.06133 |
b=0.00106 |
|
|
0.9998 |
2.0×10-5 |
0.0041 |
|
|
9 |
50 |
a=1.0372 |
c=0.05726 |
L=1.52531 |
|
0.9963 |
2.7×10-4 |
0.0158 |
|
60 |
a=1.0317 |
c=0.14772 |
L=1.76809 |
|
0.9968 |
2.6×10-4 |
0.0150 |
|
|
70 |
a=1.03128 |
c=0.13831 |
L=1.33431 |
|
0.9943 |
5.5×10-4 |
0.0206 |
|
|
10 |
50 |
c=1.13947 |
L=6.88594 |
n=1.13268 |
|
0.9996 |
3.0×10-5 |
0.0053 |
|
60 |
c=1.89469 |
L=6.22436 |
n=1.12208 |
|
0.9997 |
3.0×10-5 |
0.0051 |
|
|
70 |
c=1.80915 |
L=4.71044 |
n=1.15644 |
|
0.9992 |
8.0×10-5 |
0.0078 |
|
表3-2 微波干燥中不同薄层干燥模型的拟合结果
|
Model No. |
P(W) |
Model constants |
R2 |
χ2 |
RMSE |
|||
|
1 |
45 |
k=0.03627 |
|
|
|
0.97682 |
1.82×10-3 |
0.04176 |
|
65 |
k=0.04957 |
|
|
|
0.98566 |
1.14×10-3 |
0.03286 |
|
|
90 |
k=0.09718 |
|
|
|
0.96752 |
3.09×10-3 |
0.05241 |
|
|
135 |
k=0.14392 |
|
|
|
0.96294 |
3.96×10-3 |
0.05745 |
|
|
2 |
45 |
k=0.01382 |
n=1.29872 |
|
|
0.99954 |
4.0×10-5 |
0.00606 |
|
65 |
k=0.02594 |
n=1.21912 |
|
|
0.99881 |
1.0×10-4 |
0.00946 |
|
|
90 |
k=0.03984 |
n=1.39998 |
|
|
0.99925 |
8.0×10-5 |
0.00789 |
|
|
135 |
k=0.06173 |
n=1.46601 |
|
|
0.99948 |
7.0×10-5 |
0.00683 |
|
|
3 |
45 |
k=0.06022 |
n=0.60224 |
|
|
0.97682 |
1.9×10-3 |
0.04173 |
|
65 |
k=0.0704 |
n=0.70401 |
|
|
0.98566 |
1.21×10-3 |
0.03290 |
|
|
90 |
k=0.09858 |
n=0.98581 |
|
|
0.96752 |
3.53×10-3 |
0.05240 |
|
|
135 |
k=0.11996 |
n=1.1996 |
|
|
0.96294 |
4.94×10-3 |
0.05739 |
|
|
4 |
45 |
k=0.03948 |
a=1.07267 |
|
|
0.98688 |
1.07×10-3 |
0.03132 |
|
65 |
k=0.05286 |
a=1.05607 |
|
|
0.99161 |
7.1×10-4 |
0.02520 |
|
|
90 |
k=0.10473 |
a=1.06444 |
|
|
0.97663 |
2.54×10-3 |
0.04444 |
|
|
135 |
k=0.15301 |
a=1.05239 |
|
|
0.96988 |
4.02×10-3 |
0.05177 |
|
|
5 |
45 |
k=0.02329 |
a=1.39127 |
c=-0.36058 |
|
0.99717 |
2.4×10-4 |
0.01449 |
|
65 |
k=0.03931 |
a=1.201 |
c=-0.17122 |
|
0.99606 |
3.5×10-4 |
0.01717 |
|
|
90 |
k=0.04651 |
a=1.71385 |
c=-0.68966 |
|
0.99492 |
6.4×10-4 |
0.02066 |
|
|
135 |
k=0.04268 |
a=2.50766 |
c=-1.49348 |
|
0.99674 |
5.8×10-4 |
0.01703 |
|
|
6 |
45 |
k0=0.03948 |
k1=0.03948 |
a=0.53635 |
b=0.53635 |
0.98688 |
1.18×10-3 |
0.03136 |
|
65 |
k0=0.05285 |
k1=0.05285 |
a=0.52801 |
b=0.52801 |
0.99161 |
8.0×10-4 |
0.02513 |
|
|
90 |
k0=0.10472 |
k1=0.10472 |
a=0.53221 |
b=0.53221 |
0.97663 |
3.56×10-3 |
0.00198 |
|
|
135 |
k0=0.15301 |
k1=0.15301 |
a=0.52619 |
b=0.52619 |
0.96988 |
8.04×10-3 |
0.05177 |
|
|
7 |
45 |
k=0.05474 |
a=1.84829 |
|
|
0.99949 |
4.0×10-5 |
0.00606 |
|
65 |
k=0.07094 |
a=1.77405 |
|
|
0.99898 |
9.0×10-5 |
0.00897 |
|
|
90 |
k=0.15459 |
a=1.92932 |
|
|
0.99875 |
1.4×10-4 |
0.01043 |
|
|
135 |
k=0.23583 |
a=1.97083 |
|
|
0.99816 |
2.5×10-4 |
0.01291 |
|
|
8 |
45 |
a=-0.02829 |
b=0.0002 |
|
|
0.9971 |
2.4×10-4 |
0.01483 |
|
65 |
a=-0.04048 |
b=0.00046 |
|
|
0.99746 |
2.1×10-4 |
0.01371 |
|
|
90 |
a=-0.07243 |
b=0.00112 |
|
|
0.99463 |
5.8×10-4 |
0.02124 |
|
|
135 |
a=-0.10134 |
b=0.00157 |
|
|
0.99649 |
4.7×10-4 |
0.01770 |
|
|
9 |
45 |
a=1.07274 |
c=162.6151 |
L=64.17423 |
|
0.98688 |
1.13×10-3 |
0.03144 |
|
65 |
a=1.05608 |
c=17.52285 |
L=18.20675 |
|
0.99161 |
7.5×10-4 |
0.02413 |
|
|
90 |
a=1.06451 |
c=2.04603 |
L=4.41963 |
|
0.97663 |
2.97×10-3 |
0.04450 |
|
|
135 |
a=1.05247 |
c=1.0317 |
L=2.59635 |
|
0.96988 |
5.36×10-3 |
0.05177 |
|
|
10 |
45 |
c=0.0589 |
L=1.74752 |
n=1.2988 |
|
0.99954 |
4.0×10-5 |
0.00592 |
|
65 |
c=0.11022 |
L=1.8097 |
n=1.21934 |
|
0.99891 |
9.0×10-5 |
0.00871 |
|
|
90 |
c=0.10925 |
L=1.43366 |
n=1.39997 |
|
0.99925 |
7.0×10-5 |
0.00683 |
|
|
135 |
c=0.07379 |
L=1.06264 |
n=1.46588 |
|
0.99948 |
6.0×10-5 |
0.00548 |
|
表3-3 不同干制方法对枣果Ps、TFs、Vc和抗氧化特性的影响
|
干制处理 |
TPs (mg GA/g DW) |
TFs (mg Rutin/g DW) |
Vc (mg/ g DW) |
FRAP (mg Vc/g DW) |
DPPH (mg Trolox/g DW) |
ABTS (mg Trolox/g DW) |
|
Fresh FD AD50 AD60 AD70 SD MD |
13.85 ± 0.58b 20.98 ± 1.77a 11.24 ± 0.43c 12.90 ± 0.80b 12.80 ± 1.07b 9.66 ± 0.51d 13.64 ± 1.20b |
9.83 ± 0.34b 11.61 ± 0.14a 8.86 ± 0.44b 7.20 ± 0.37c 8.41 ± 0.25bc 7.20 ± 0.31c 10.50± 1.16ab |
10.02 ± 0.2 7.91 ± 0.10b 0.41 ± 0.01f 0.72 ± 0.02e 1.27 ± 0.01c ND 0.66 ± 0.09d |
15.17 ± 0.53 a 15.50 ± 0.24 a 7.99 ± 0.40c 6.02 ± 0.16d 7.97 ± 0.40c 5.52 ± 0.11e 14.52 ± 0.13b |
26.27 ± 0.41a 8.51 ± 0.13b 5.17 ± 0.17d 5.60 ± 0.07c 5.53 ± 0.10c 4.49 ± 0.05e 4.96 ± 0.11d |
72.10 ± 0.66a 33.65 ± 0.37b 13.87 ± 0.34c 13.75 ± 0.49c 14.42 ± 0.25c 12.64 ± 0.15d 28.00 ± 0.24e |
|
|
|
|
|
|
|
|
表3-2 不同干制方法对枣果酚类物质含量影响
|
干制处理 |
儿茶素 (mg/100 g DW) |
香草酸 (mg/100 g DW) |
咖啡酸 (mg/100 g DW) |
丁香酸 (mg/100 g DW) |
表儿茶素 (mg/100 g DW) |
芦丁 (mg/100 g DW) |
|
Fresh FD AD50 AD60 AD70 SD MD |
15.40 ± 0.70cd 33.69 ± 2.30a 14.16 ± 0.25e 14.38 ± 0.52d 16.82 ± 0.77bc 12.61 ± 0.50f 17.68 ± 0.22b |
7.97 ± 0.56a 8.80 ± 0.33a 5.53 ± 0.16c 5.38 ± 0.14c 6.73 ± 0.80b 4.92 ± 0.12d 4.80 ± 0.19d |
1.56 ± 0.06a 0.51 ± 0.01b ND ND ND ND ND |
5.14 ± 0.24a 5.36 ± 0.11a 3.78 ± 0.08c 3.87 ± 0.13bc 4.03 ± 0.11b 3.01 ± 0.03e 3.36 ± 0.04d |
2.84 ± 0.32b 6.22 ± 0.64a ND 0.50 ± 0.09d 0.17 ± 0.01e ND 4.44 ± 0.17c |
8.54 ± 0.13a 8.32 ± 0.1b 7.80 ± 0.38b 8.75 ± 0.69a 8.30 ± 0.29ab 6.49 ± 0.22c 8.95 ±0.36a |
|
|
|
|
|
|
|
|
表3-5不同干制方法的枣果中WSP的色谱峰RT及其Mp
|
干制 |
WSP |
||
|
处理 |
RT (min) |
Mp (kDa) |
|
|
Fresh
AD50 AD60
AD70
SD
MD |
11.434 ± 0.018 15.490 ± 0.013 12.155 ± 0.014 12.172 ± 0.010 13.420 ± 0.028 12.184 ± 0.022 14.064 ± 0.011 12.168 ± 0.011 14.314 ± 0.007 12.352 ± 0.007 14.305 ± 0.011 |
737.43 ± 9.08a 48.67 ± 0.44g 454.89 ± 4.31b 449.58 ± 3.19b 194.90 ± 3.69d 446.15 ± 6.77b 126.58 ± 0.96e 451.09 ± 3.21b 107.02 ± 0.56f 398.58 ± 1.81c 107.71 ± 0.81f |
|
表3-6不同干制方法的枣果中CSP的色谱峰RT及其Mp
|
干制 |
CSP |
|
|
处理 |
RT (min) |
Mp (kDa) |
|
Fresh AD50 AD60
AD70
SD MD |
11.860 ± 0.008 12.130 ± 0.010 12.158 ± 0.011 13.562 ± 0.008 12.198 ± 0.010 13.844 ± 0.012 12.155 ± 0.011 11.880 ± 0.010 16.604 ± 0.012 |
568.59 ± 4.318a 462.56 ± 3.07c 453.97 ± 3.44d 177.20 ± 1.01f 442.11 ± 3.14e 146.67 ± 0.69g 454.88 ± 4.31cd 546.92 ± 3.63b 23.09 ± 0.18h |
表3-7 不同干制方法的枣果中SSP的色谱峰RT及其Mp
|
干制 |
SSP |
||||
|
处理 |
RT (min) |
Mp (kDa) |
|
||
|
Fresh
AD50
AD60
AD70
SD
MD |
11.996 ± 0.011 15.146 ± 0.005 12.008 ± 0.011 15.146 ± 0.014 12.001 ± 0.022 15.368 ± 0.024 12.003 ± 0.023 15.460 ± 0.014 12.007 ± 0.012 17.075 ± 0.007 12.005 ± 0.014 15.726 ± 0.007 |
506.02 ± 3.83a 61.29 ± 0.38b 502.14 ± 3.57a 61.31± 0.58b 503.67 ± 7.6 52.86 ± 0.88c 503.67 ± 7.1 49.67 ± 0.47d 502.48 ± 4.40a 16.83 ± 0.08e 502.98 ± 4.76a 41.56 ± 0.20e |
|
||
主要结论
提高AD温度或MD功率大大缩短时间，枣果AD过程是一个没有明显拐点的降速干燥阶段；枣果MD分提速阶段、快速干燥阶段、降速干燥阶段；
有效扩散系数Deff一方面随功率或温度的升高而逐渐增大；另一方面，Deff随着水分含量的降低而升高；
干制处理均导致山梨醇含量的降低；FD能够很好的保持枣果中的果糖和葡萄糖；但蔗糖含量显著上升(p<0.05)，而其它干制处理均导致枣果中蔗糖含量的显著下降(p<0.05)；
50%wb-45W的热风微波干燥组合是较为理想的大枣热风-微波联合干燥方式。
干制处理导致枣果CWM、WSP和SSP含量显著下降(p<0.05)而其CSP含量显著增加(p<0.05)；高温或低温处理均导致枣果中CWM、WSP和SSP含量的更严重的降低。
主要结论
FD处理很好的保留枣果中的cAMP和cGMP，而其余干制处理均导致cAMP和cGMP含量的显著下降(p<0.05)；除FD处理外，AD50处理其cAMP和cGMP保留率同时达到高峰，高温或者低温均导致cAMP和cGMP含量更为严重的下降。
综合以上分析不难得出，去除水分同时保证栆类各营养成份的干燥方式就是真空冷冻干燥。经过多年发展真空冷冻干燥同其它干燥方式相比成本高的弱点已经基本消除。
真空冷冻干燥食品即将跨越式进入食品市场，以其的形象展现给消费者。
010～58895377
