【作者】 周国林；

【导师】 别之龙；

【作者基本信息】 华中农业大学 ， 种植， 2008， 硕士

【摘要】 豇豆是我国重要蔬菜种类之一,武汉市豇豆种植面积约10万亩,2007年豇豆被列为武汉市十大蔬菜优势品种。武汉市豇豆除鲜销外,还进行腌制加工,腌制豇豆占豇豆总产量40%左右。蔬菜硝酸盐含量超标问题,已经成为公众关注的焦点,豇豆硝酸盐含量、加工豇豆亚硝酸盐含量是否超标是影响其质量的重要指标。本文针对武汉市豇豆栽培和加工过程中硝酸盐累积和亚硝酸盐转化问题,分别研究了豇豆不同品种(包括不同熟性、不同豆荚大小、不同颜色颜色、不同植株生长势等)的豆荚、叶片、茎;同一品种豆荚、叶片、茎、根四个不同部位;豆荚不同成熟期的硝酸盐含量变化规律。同时研究了豇豆不同品种及不同食盐浓度腌制过程中硝酸盐和亚硝酸盐变化规律。结果表明:1、豇豆不同品种的豆荚中硝酸盐含量有很大差异。豆荚中硝酸盐含量与豆荚直径(r=-0.93579)、长度(r=-0.94108)呈极显著负相关。豆荚直径和长度越大,豆荚中硝酸盐含量越低。豆荚中硝酸盐含量最高的品种台交一号(803mg/kg)是含量最低的品种5号豇豆(138.5mg/kg)的5.8倍。豇豆晚熟品种比早熟品种豆荚中硝酸盐累积量少。2、豇豆不同品种叶片中硝酸盐含量不同。有架豇豆品种的植株叶片大小与叶片中硝酸盐含量呈显著负相关r=-0.95693。品种叶片越小,叶片中硝酸盐含量越高。小叶品种叶片中硝酸盐含量(早翠919.0mg/kg)高于大叶品种(春秋红651.4 mg/kg)。无架豇豆叶片中硝酸盐含量(1530.5 mg/kg)显著高于有架豇豆。3、豇豆不同品种茎中硝酸盐含量,以豇豆植株生长势强的品种硝酸盐含量(武蔬白豇460.6 mg/kg)低于生长势弱的品种(1276.6 mg/kg)。无架豇豆的茎中硝酸盐含量(80 mg/kg)极显著低于其他品种。4、豇豆不同部位硝酸盐含量分布不同。在豇豆结荚期,硝酸盐含量顺序是叶片＞茎和豆荚。叶片中硝酸盐含量(加工七号叶片850.2 mg/kg)高于商品荚(加工七号380 mg/kg)和茎(317.9 mg/kg),荚和茎中硝酸盐含量相差不大,根中硝酸盐含量无明显规律。在豇豆结荚前,豇豆不同品种硝酸盐在不同部位分布规律不同,生长势强的品种叶片中硝酸盐含量高于茎中含量,生长势弱的品种茎中的硝酸盐含量高于叶片中含量。5、豆荚在不同时期的硝酸盐含量,以嫩荚硝酸盐含量最低(228.6 mg/kg),随着豆荚逐渐成熟,硝酸盐含量上升(380.5 mg/kg),老荚含量稍有下降(378.2 mg/kg),但与商品荚基本相当。6、豇豆加工过程中亚硝酸盐含量有一个高峰期,峰值的高低随豇豆品种不同而异。在食盐浓度为12%条件下,一般从第三天至第七天豇豆中亚硝酸盐含量逐渐上升,第7天达到最高,以后硝酸盐含量逐渐降低。7、豇豆加工试验参试品种中“加工七号”加工过程中从第3天到第13天的亚硝酸盐含量(2.7581 mg/kg、3.5895 mg/kg、4.0179 mg/kg、2.0184 mg/kg、1.3214 mg/kg、0.5293 mg/kg)未超过国家关于蔬菜中亚硝酸盐残留量的标准(≤4mg/kg)。从加工后产品颜色、消费习惯等角度综合考虑,“加工七号”是最适宜的加工型品种。8、多数豇豆品种在食盐浓度为12%时,第3～9天的亚硝酸盐含量高于国家安全标准(4mg/kg),进行豇豆加工时在加工后9天以上食用才可以保证亚硝酸盐方面的安全。9、豇豆加工过程中硝酸盐含量总体呈逐渐下降趋势,但不同品种以及同一品种不同食盐浓度之间的变化规律并不明显。更多还原

【Abstract】 Yardlong Bean(Vigna unquiculata W.sp.sesquipedalis(L.) Verd),an important vegetable,was planted one hundred thousand mu in wuhan city.Yardlong Bean was listed as one of ten dominant vegetable varieties in 2007.The pickled Yardlong Bean accounted for about 40%of the total output.The nitrate content of vegetable over the National Standard Range has become the focus of public attention as an important indicator of vegetable quality.To clarify the accumulation of nitrate and nitrite in the Yardlong Bean issue in cultivation and processing,effects of Yardlong Bean varieties(including various ripening,pod color,plant growth potential,and so on),different organs,different pod maturity on the change of the nitrate and nitrite were studied.Effects of Yardlong Bean varieties and NaCl concentrations on the change of the nitrate and nitrite content in pickling process were also studied.The results showed:1.The nitrate contents of the pods were different among the Yardlong Bean varieties. The highest content(803mg/kg) is 5.8 times the lowest one(138.5mg/kg).The nitrate content is higher in Late-maturing varieties than in early-maturing,also in larger pods than in smaller one.2.The nitrate contents of the leaves were different among the Yardlong Bean varieties.The nitrate content is higher in small-leaf varieties(919.0mg/kg) than in large-leaf ones(651.4 mg/kg),also in Non-bracket Yardlong Bean than in bracket Yardlong Bean.3.The nitrate contents of the stems were different among the Yardlong Bean varieties. The nitrate content is higher in Yardlong Bean varieties with weak growth potential(1276.6 mg/kg) than in those with strong growth potential(460.6 mg/kg), lower in Non-bracket Yardlong Bean than in the other varieties.4.The nitrate contents of the different organs were different.During the pod bearing period,The nitrate content is higher in leaves(850.2 mg/kg) than in stems(317.9 mg/kg) and pods(380 mg/kg),the last two organs showed no difference in nitrate content.The nitrate contents in the roots had no obvious trend.Before the pod bearing period,the nitrate content is higher in leaves of Yardlong Bean varieties with strong growth potential and stems of Yardlong Bean varieties with weak gowth potential.5.The nitrate contents of baby pod(228.6mg/kg) is the lowest.With the pods becoming mature gradually,the nitrate contents of pods increased(380.5 mg/kg). The nitrate contents of old pods decreased(378.2 mg/kg).Old pods and commodity ones showed no significant difference in nitrate content.6.During the Yardlong Bean process,nitrite content had peak level,and the level depended on the varieties.When the NaCl concentration was 12%nitrite content increase during 3 to 7 days after pickling.The content was the highest 7 days after pickling,aterwards decreasing gradually.7.The nitrite content of ’jiagong No.7’ Yardlong Bean(2.7581 mg/kg、3.5895 mg/kg、4.0179 mg/kg、2.0184 mg/kg、1.3214 mg/kg、0.5293 mg/kg) is below the the National Standard Range.The Yardlong Bean is the best processing variety in terms of the color of processed product,consumer point and the nitrite content.8.The safety time of eating pickled Yardlong Bean was 9 days after pickling,since the the nitrite content of most Yardlong Bean varieties is over the the National Standard Range with the NaCl concentration being 12%during 3 to 9 days after pickling.During the process of Yardlong Bean,the nitrate contents decreased on the whole,the change of the nitrate content showed no trends among the Yardlong Bean varieties and among the NaCl concentrations.更多还原