【作者】 黄劲松；

【导师】 杜先锋；

【作者基本信息】 安徽农业大学 ， 农产品加工与贮藏工程， 2007， 硕士

【摘要】 脱水蔬菜作为一种新兴的食品种类越来越多地受到人们的关注。在日本、美国、香港等国家和地区,脱水蔬菜已成为一种适应现代人快节奏生活方式的流行食品。在我国它不仅在方便食品领域大量使用,而且也是旅游、军队、地质等部门解决吃菜难的有效方法。脱水蔬菜具有保持原材料的色、香,味和营养成分,食品不易变质、复水性好、重量轻、可在常温下贮藏等优点。本实验首先对蘑菇进行贮藏保鲜,然后通过真空冷冻干燥技术生产脱水蘑菇,优化出最佳的实验条件,并将其与传统的热风干燥方式进行对比,发现冷冻干燥的蘑菇片在外形、营养成分、香气成分的保留及复水性等方面比热风干燥具有明显的优势。实验包括:1蘑菇保鲜技术及在保鲜过程中特征性香气变化规律的研究1)对褐变抑制剂的选择,以感官评分及蘑菇的特征性香气作为褐变抑制剂的指标,结果表明,添加褐变抑制剂量为半胱氨酸1.0g/L,抗坏血酸0.8g/L,柠檬酸20g/L,浸泡时间20min,可获得感官评分及特征性香气成分1-辛烯-3-醇含量高贮藏的蘑菇,此时所得的蘑菇褐变程度小,感官评分高,从而为后序的蘑菇干燥做准备,其贮藏保鲜的目的是确保原料在加工之前的质量,防止其褐变、腐烂而采取的措施。（2）通过对蘑菇在贮藏期间主要的特征性香气进行分析,结果表明随着贮藏时间的延长,1-辛烯-3-醇含量逐渐下降,其相对含量占总挥发性香气组分含量的80%以上,其他成分如苯甲醛、3-辛醇、3-辛酮含量在贮藏期间变化不大,为蘑菇的脱水干燥选择质量好的原料。2蘑菇真空冷冻干燥工艺（1）采用二次通用旋转组合设计,建立了预冻速率、升华温度、解析温度对于燥后蘑菇复水比的回归方程,并对在区间范围内进行预测:在预冻速率2.5℃/min、在0℃升华5h、13℃保持6h,得到的复水比达5.62,实际测定干燥后的复水比为5.49,相对误差为2.37%,为今后采用冷冻干燥生产果蔬提供一定的理论数据。3干燥方式对蘑菇品质影响（1）比较了热风干燥及冷冻干燥两种干燥方式对蘑菇干燥后品质影响,营养成分如灰分、多糖、蛋白质、氨基酸等。结果表明灰分,粗纤维含量差别不大,而经冷冻干燥后蘑菇的多糖、蛋白质、游离氨基酸及水溶性维生素含量高于热风干燥。由于冷冻干燥的蘑菇片切片布满大小均一、数量多的微孔,呈现海绵状的多孔结构,而热风干燥后的蘑菇片切面微孔大,数量少,且不均匀,外表皱缩,形成致密的硬壳,致使冷冻干燥的蘑菇比热风干燥具有好的复水性能。冷冻干燥后的特征性的香气成分个数与新鲜的蘑菇相同,含有苯甲醛、1-辛烯-3-醇,3-辛醇和3-辛酮,而经过热风干燥后的蘑菇仅有苯甲醛,所以热风干燥后的蘑菇没有新鲜蘑菇的香味。（2）建立了高效毛细管电泳测定蘑菇中水溶性维生素的方法,采用压力进样5sec,柱温25℃,分离电压20KV,维生素V_B1,V_B6、烟酸、V_B2和Vc的检测波长190nm.,电泳缓冲液为20mM硼砂～硼酸缓冲液pH8.72,运行时间10min,即可对蘑菇中多种维生素实现良好分离,同时比较了经过冷冻干燥和热风干燥两种方式干燥的蘑菇,结果表明冷冻干燥方式干燥的蘑菇对维生素的保留明显高于热风干燥方式。（3）分别用微波真空干燥和冷冻干燥技术对常见果蔬进行干燥,用微波真空技术对洋葱、苹果片、香蕉片、蒜片、香菇、葱叶进行干燥;用冷冻干燥技术对蒜片、苹果片、胡萝卜、生姜、香葱、红辣椒也进行干燥,结果发现冷冻干燥的果蔬比微波真空干燥具有变形程度小、褐变程度小的优势。更多还原

【Abstract】 Dehydrated vegetables are a new-style food species that are favored by an increasing number of people.The food species have been become prevalent food which rapid rhythmic lifestyle needs in Japan,America or Hong Kong.Not only dehydrated vegetables are used in convenient food fields,but also in the department of tourism,frontier defense,and geological perambulation.It can preserve the color, aroma,taste and nutritional ingredients of raw materials,also have many advantages in indefectible quality,high re-absorption rate and portable weight and so on.The dehydrated mushroom pieces are made by freeze-drying technology in this experiment.The mushroom dehydrated by freeze-drying are more advantages in appearance,nutritional ingredients and volatile ingredients and re-solution rate than air-dryingTrails included1.Fresh-preserving technology and the change of characteristic aroma of mushroom（1）To confirm the effect of conventional browning inhibitors on the fresh-preserving, the orthogonal experiment is carried out.The sensory assess and the content of 1-octene -3-ol are exploited to assess guidelines.The results show that the addition dosage of Cys Vc and citric acid is respectively 1g,0.8g and 20g per liter water with the general consideration of the sensory evaluation and the content of 1-octene-3-ol for the preparation the dehydrated mushroom（2）The major aroma components of fresh mushrooms are benazldehyde,1-octene-3-ol, 3-octenone and 3-octenol,the content of 1-octene-3-ol is highest in these aroma components,the content of 1～octene～3～ol decreases with the time extension, accounting for 80%in total aroma components the content of 3-octenol are little, while the content of benazldehyde and 3-octenone change little during storage period.2.Freeze-drying technology of mushrooms pieces（1）Rotational designs are used to ensure the technology of freeze-drying.To establish the regressive equation about the three variable of the effect of pre-freeze rate, sublimation temperature and resolution temperature,the results showed that the pre-freeze rate are2.5℃/min,sublimation temperature and resolution temperature are 0℃,and 13℃in area coverage,the re-absorption rate of ultimate mushrooms are 5.62, the actual re-absorption rate 5.49,the relative deviation is 2.37%.3.Effect of drying styles on the quality of mushroom（1）The mushroom is dried by the freeze-drying and hot-air drying respectively and there are obvious differences in nutritional components between the products.The results indicated that the free amino acid and polysaccharides and protein in freeze-dried products are higher than the hot-air dried products.This paper also explained the reason that the re-hydrated performance by freeze-drying is better than air-drying product from microcosmic angles.The reason is that the symmetrical micro-hole in freeze-drying mushroom pieces is more than air-drying mushroom.The number of characteristic aroma components in freeze-dried products is same to fresh mushrooms,including 1-octene-3-ol,3-octenol,and 3-octene benazldehyde,while the products dried by hot-air drying merely have.benazldehyde（2）A rapid procedure using capillary electrophoresis to measure water-soluble vitamins in mushroom powder,The effective component of the samples was purified and enriched by means of a solid phase extraction step with a preconditions SPE column..Optimum separation of V_B1,,V_B2,V_B6,V_C and Nocitinamide were obtained by capillary electrophoresis using 20mM borate buffer solution（pH8.72）,temperature and working voltage 25℃and 20kV in nearly 10 minutes（3）Common vegetables are dried by the vacuum micro-wave and freeze-drying.The dryness of onion,apple pieces,banana pieces,garlic pieces,shallot pieces in micro-wave Vacuum drying;garlic pieces,apple pieces,carrot,shallot pieces,chili pieces are dried by freeze-drying.Compared to the two drying style,It shows that the products dried by freeze-drying are less transformative than micro-wave vacuum drying更多还原