微波加热下10种不同氨基酸溶液的介电特性  

Dielectric properties of 10 different amino acid solutions during microwave heating

作　　者：向萍 邱伟强[1] 金英善[3] 冯宇辉 金银哲[1,2] XIANG Ping;QIU Weiqiang;JIN Yingshan;FENG Yuhui;JIN Yinzhe(College of Food Sciences and Technology,Shanghai Ocean University,Shanghai 201306,China;Engineering Research Center of Food Thermal-processing Technology,Shanghai 201306,China;College of Bioscience and Biotechnology,Yangzhou University,Yangzhou 277600,Jiangsu,China;Jilin Tabacco Industry Co.,Ltd,Yanji 133000,Jilin,China)

机构地区：[1]上海海洋大学食品学院,上海201306 [2]食品热加工工程中心,上海201306 [3]扬州大学生物科学与技术学院,江苏扬州277600 [4]吉林烟草工业有限责任公司,吉林延吉133000

出　　处：《上海海洋大学学报》2022年第2期574-585,共12页Journal of Shanghai Ocean University

基　　金：国家重点研发计划(2020YFD0900905)。

摘　　要：为了探究不同氨基酸溶液在微波加热下的介电特性,采用网络分析仪和同轴探针法测定10种氨基酸[甘氨酸(Gly)、脯氨酸(Pro)、半胱氨酸(Cys)、谷氨酰胺(Gln)、赖氨酸(Lys)、蛋氨酸(Met)、组氨酸(His)、精氨酸(Arg)、酪氨酸(Tyr)和色氨酸(Trp)]溶液在微波(250 W)加热(0、1、3、5 min)下的介电特性。结果表明:在0.3~3 GHz的频率范围内,除了Tyr无明显变化外,其他氨基酸溶液的介电常数随着频率的增加逐渐降低。在微波加热过程中,Arg、Lys溶液的介电损耗随着频率的增加出现降低的趋势,而其他氨基酸溶液(除Gln外)呈增加的趋势。微波加热过程中Gln溶液的介电损耗在0.9 GHz左右出现明显的转折点(尤其是在微波加热3 min和5 min时),呈先下降后上升的趋势。915 MHz时的穿透深度大于2450 MHz。在加热3 min时,915 MHz下Tyr溶液的穿透深度最大为(180±0.12)mm,2450 MHz下Trp溶液的穿透深度最大为(20±1.5)mm。Arg、Lys溶液在微波加热过程中因电离而导致其pH降低。氨基酸的分子量和等电点影响杂环族氨基酸和脂肪族氨基酸溶液的穿透深度,且氨基酸溶液的穿透深度与氨基酸分子量之间的相关性(R^(2)>0.90)大于其等电点(R^(2)>0.82)。随着加热时间的增加,杂环族氨基酸(Tyr、His、Trp、Pro)溶液的临界频率降低,而脂肪族氨基酸(Met、Lys、Arg、Gly、Gln、Cys)溶液的临界频率增加(P<0.05)。In order to investigate the dielectric properties of the different amino acid solutions during microwave heating,the 10 kinds of amino acid solutions[glycine(Gly),proline(Pro),cysteine(Cys),glutamine(Gln),lysine(Lys),methionine(Met),histidine(His),arginine(Arg),tyrosine(Tyr)and tryptophan(Trp)]were determined by network analyzer and coaxial probe technology.These solutions were heated for(0,1,3,5 min)using microwave irradiation(250 W).Except for Tyr,the dielectric constant of other amino acid solutions gradually decreased with the increasing of frequency at the frequency of 0.3~3 GHz.During microwave heating,the dielectric loss of Arg and Lys solutions tended to decrease with increasing frequency,while other amino acid solutions(except Gln)tended to increase.During the microwave heating process,the dielectric loss of Gln solution displayed an obvious turning point at 0.9 GHz(especially under microwave heated for 3 min and 5 min),which showed a trend of decreasing first and then increasing.The penetration at 915 MHz was higher than 2450 MHz.When heating for 3 min,the maximum penetration depth of Tyr solution at 915 MHz was(180±0.12)mm,and the maximum penetration depth of Trp solution at 2450 MHz was(20±1.5)mm.The pH of Arg,Lys solutions decreased due to ionizing during microwave heating.The molecular weight and isoelectric point of amino acids affect the penetration depth of heterocycle amino acid and aliphatic amino acid solutions,and the correlation between the penetration depth of amino acid solution and the molecular weight of amino acid(R2>0.90)was higher than its isoelectric point(R2>0.82).With the increase of heating time,the critical frequencies of heterocyclic amino acids(Tyr,His,Trp,Pro)solutions decreased,whereas the critical frequencies of aliphatic amino acids(Met,Lys,Arg,Gly,Gln,Cys)solutions increased(P<0.05).

关 键 词：氨基酸溶液 微波加热 介电特性 穿透深度 临界频率 

分 类 号：TS201.2[轻工技术与工程—食品科学]