基于可视传感器阵列的鳊鱼新鲜度评价模型研究

目的 建立基于可视传感器阵列的鳊鱼新鲜度评价模型。方法 研究采用可视传感阵列与鱼体进行无接触式反应, 提取阵列反应前后的颜色变化信息来表征鱼的气味特征; 同时根据行业标准SC/T3032-2007测得表征鱼新鲜度的挥发性盐基氮(TVB-N)含量; 将可视传感技术所得的特征信息与TVB-N指标含量进行关联, 分别建立基于可视传感技术鱼新鲜度评价的定性模型BP神经网络和联合间隔偏最小二乘法(siPLS)定量模型。结果 BP神经网络模型精度较高, 训练集正确率为86.79%, 预测集正确率为86.43%; siPLS模型次之, 模型校正集和预测集的正确率分别为82.52%和80.67%。结论 可视传感器新技术所测得指标与TVB-N相关性较大, 可快速预测出鱼在储藏期间TVB-N的变化从而能够快速、无损地评价鱼类新鲜度。     

紫菜薹色素的提取及其理化性质研究

以紫菜薹为原料 ,用 30 %乙醇溶液浸提制得紫菜薹色素 ,并对其理化性质进行了研究。结果表示该色素在弱酸性条件下 ,具有较好的稳定性 ,在食品工业中有一定的开发利用价值。     

New Measured Weight for One Cup Raw Kale Reduces Nutrient Intake of Individuals Following the Wahls™ Diet

Kale is a nutrient-dense, dark-green leafy vegetable often eaten raw in salads or added to smoothies. The USDA National Nutrient Database for Standard Reference Release 26 reports the weight for one cup raw, chopped kale as 67 grams, among the highest for raw leafy vegetables. Objectives: Measure the weight of one cup moderately packed raw kale with stems and tough midrib parts removed and evaluate the impact of the new cup weight on nutrient intake of individuals consumingraw kale. Methods: Six staff members measured curly and lacinato kale using standard procedures and 14 study participantsconsuming 4-6 cups raw leafy vegetables/day measured one cup curly kale in their usual manner. Twenty-seven dietary recalls obtained from participants following the Wahls™ diet were entered intothe Nutrition Data System for Research and then recalculated using staff-measured curly kale cup weight. Results: Mean(SE) staff cup weight for lacinato kale was significantly higher than curly kale [21.3(1.4)g vs 16.0(1.4)g; p<0.0001]. Percent refuse was also higher for lacinato kale [mean(SD) 42.0(11.4)% vs 28.5(3.9)%; p=0.012]. Mean(SD) weight of moderately packed participant-measured cups [17.5(6.4)g]was similar to staff cup weightbutfirmly packed participant cupsweighed more [46.4(4.1)g]. Intake of vitamins K, C, A, manganese, copper, and folatewere significantly lower for diets calculated with the staff cup weight (p<0.0001). Conclusions: The new measured cup weight of raw kale is lower than previously reportedand reduces nutrient levels in diets containing raw kale. Verification of cup weights for other raw leafy vegetables may be warranted.     

华南特产蔬菜菜心的营养成分及营养评价

经测定结果表明,每100g菜心食用部分,其能量为89kJ、水分93.5g、灰分1.10g、粗纤维0.91g、粗蛋白2.15g、粗脂肪0.69g、碳水化合物1.65g、VC52.16mg、总黄酮达1.73mg/g,芦丁含量为0.14mg/g。菜心含14种矿质营养元素,以N、Ca最高,Cd最低,特别是P、Fe、Zn、Mn等营养元素含量较丰富,分别比苹果高2～21倍、比番茄高2.5～14倍。菜心除胱氨酸未检出外,含有其它17种氨基酸,以谷氨酸最高、色氨酸最低;总氨基酸含量达275mg/g,必需氨基酸含量为115.01mg/g,鲜味氨基酸含量(天门冬氨酸和谷氨酸)为66.08mg/g。菜心共检出9种饱和脂肪酸和4种不饱和脂肪酸,未检到亚油酸、二十二酸、二十四酸及生物碱。饱和脂肪酸总量达26.44%,以软脂酸为主,占17.81%;不饱和脂肪酸总量达73.58%,以亚麻酸为主,占61.35%。     

硝基腐植酸螯合铁、钙在青菜上的应用效果

为验证自制的硝基腐植酸螯合铁和螯合钙作为肥料增效剂在青菜上的实际应用效果,以品名为"苏州青"的青菜为试验对象,进行两种增效剂的肥效试验。结果表明:硝基腐植酸螯合铁和螯合钙配合一定水溶肥使用时,青菜质量分别增加10.32%和40.17%,效果显著。     

Glucosinolate content of Brassica vegetables-Chinese cabbages Pe-tsai (Brassica pekinensis) and Pak-choi (Brassica chinensis)

The glucosinolate content of 19 cultivars of pe-tsai and three cultivars of pak-choi Chinese cabbage (Brassica pekinensis Lour) Rupr and (Brassica chinensis L, respectively) has been determined using high performance liquid chromatography. The levels of total glucosinolates were 0.097-0.337 g kg^?1 fresh weight (mean 0.198) in pe-tsai and 0.39-0.704 g kg^?1 (mean 0.534) in pak-choi. The main components present were (2-hydroxybut-3-enyl-progoitrin), but-3-enyl- (gluconapin), 5-methylsulphinylpentyl- (glucoalyssin) and pent-4-enyl (glucobrassicanapin) glucosinolates, respectively. In comparison with other UK brassicas and American cultivars of Chinese cabbage, both the UK-grown pak-choi and pe-tsai are low in glucosinolates.     

智能嵌入式气调包装对上海青贮藏品质影响的研究

智能嵌入式气调试验台上,通过测定质量损失率、叶绿素质量分数、颜色、感官评价,研究低温、温湿双控、气调三种保鲜模式对上海青贮藏品质的影响,结果表明,气调保鲜能较好地抑制上海青贮藏期间(14 d)水分的丢失,但PET包装盒未能较好地抑制上海青样品的黄化。在6 d以内的贮藏期,带包装上海青在温湿双控保鲜模式下能保持较好的感官品质,在质量损失率、叶绿素质量分数、b*值等均较好。     

白菜中二硫代磷酸酯类有机磷农药降解动力学研究

培养8 叶期无菌白菜幼苗,添加5 种二硫代磷酸酯类有机磷农药（马拉硫磷、乐果、甲拌磷、乙拌磷及特丁硫磷）,用气相色谱及液相色谱-质谱联用法检测二硫代磷酸酯类农药及O,O-二甲基二硫代磷酸酯残留量。结果表明：二硫代磷酸酯类农药的含量在实验过程中呈减少的趋势,农药在样本培养过程被逐渐降解,10 d内降解水平为13.4%～65.0%,无菌苗添加药物组降解速率明显低于正常培养添加药物对照组。使用一级反应动力学模型对农药代谢动力学进行评价,无菌条件下马拉硫磷降解速率最快,降解速率常数为0.034 67,降解半衰期为19.9 d,特丁硫磷降解速率常数最小,降解速率常数为0.007 17,降解半衰期为96.7 d,乐果、甲拌磷及乙拌磷相对稳定,但降解动力学差别较大。     

紫芜菁乙醇提物对Caco-2细胞氧化损伤的保护作用

探讨紫芜菁乙醇提取物(BREE)的体外抗氧化能力及其对人肠上皮Caco-2细胞氧化损伤保护效果。二苯代苦味酰基自由基(DPPH)、羟基自由基(·OH)清除率与总还原力评估BREE的体外抗氧化力。过氧化氢(H_2O_2,150μmol/L)建立Caco-2细胞氧化损伤模型评估BREE的细胞保护效果。受损细胞生存率的影响以MTT法测定。细胞内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化酶(GSH-Px)水平依说明用试剂盒测定。硫代巴比妥酸法测定丙二醛(MDA)含量。2’,7’-二氢二氯荧光黄双乙酸钠法测定细胞内活性氧(ROS)水平。酶联法测定白介素(Interlukin,IL)-1β和IL-8的水平。BREE具有较强的自由基(DPPH和·OH)清除力和总还原力。BREE能显著抑制H_2O_2造成的细胞死亡,提高受损细胞中抗氧化物酶(SOD、CAT和GSH-Px)活性,降低受损细胞内MDA与ROS的生成,并抑制IL-1β和IL-8的分泌。结果提示,BREE具有较强的体外抗氧化能力,能增强细胞内源性抗氧化酶的活力显著改善H_2O_2引发的Caco-2细胞氧化应激损伤并降低炎症反应。     

美拉德反应基液——鳊鱼蛋白酶解液的制备

研究以鳊鱼蛋白为原料,经过酶解反应,以期获得风味良好的美拉德反应基液。通过风味蛋白酶与其它蛋白酶复配筛选组合,综合考察影响酶解反应的4个因素:温度、时间、pH和酶添加量,以水解度(DH)为响应值,采用Box-Benhnken响应面分析法确定最佳反应条件。研究结果表明,以风味蛋白酶和复合蛋白酶(3:1)复配的组合水解度最高,酶解反应条件为:温度51.5℃,时间5.7h,pH7.7,酶添加量0.80%,水解度可达79.46%。在该条件下制得的酶解液腥味弱,苦味值低,有淡淡的鱼香味,可以作为美拉德反应的基液。