货架陈列期间光照处理对鲜切青椒品质的影响

为研究白光、红光、蓝光、绿光光照以及避光处理对鲜切青椒（Capsicum annuum L.）品质的影响,将鲜切青椒在货架陈列期用不同光照处理,贮藏5 d后,比较鲜切青椒质量损失率、颜色、相对电导率、丙二醛含量和风味的差异。结果发现：在各光照处理组中,绿光处理组鲜切青椒的质量损失率最低,为3.75%,且该处理对可溶性固形物质量分数、果实水渍化损伤程度、果实颜色变化的影响均较小,与新鲜样品相比,其色差仅为3.22,显著低于白光处理组（P＜0.05）;并且与白光处理组相比,绿光处理对鲜切青椒的风味没有显著影响（P＞0.05）。因此,绿光处理有助于维持鲜切青椒在货架陈列期的品质。     

Bleaching of Green Peas and Changes in Enzyme Activities of Seeds under Simulated Climatic Conditions

ABSTRACT: The effects of simulated climatic conditions on green color loss of peas ( Pisum sativum ) and related enzyme activities were investigated. Seeds of 2 green pea cultivars showing different resistance to green color bleaching were subjected to light only, soaking in water without light, and soaking in water with light. Green color loss and chlorophyll loss were highest in seeds soaked in water and exposed to light, less in seeds soaked in water under dark conditions, and least in seeds exposed to light only. Increased chlorophyllase activity was associated with loss of green color and chlorophyll, whereas no significant relationship was found between chlorophyll loss and lipoxygenase or chlorophyll-degrading peroxidase activity. Susceptible and resistant cultivars had significant differences in green color, chlorophyll content, chlorophyll a/b ratio, and chlorophyll degradation kinetics constant when seeds were soaked in water and exposed to light. Enzyme activity was not significantly different between the cultivars. Soaking led to more green color loss, chlorophyll breakdown, and chlorophyllase activity than light exposure. Chlorophyllase may be the key enzyme responsible for green pea bleaching instead of the oxidative chlorophyll degradation pathway with lipoxygenase or chlorophyll-degrading peroxidase.     

货架陈列期间光照处理对鲜切芹菜叶品质的影响

评价货架陈列期间光照处理对鲜切芹菜叶品质的影响。研究在4℃货架陈列期间,使用白光、红光、绿光和蓝光对鲜切芹菜叶进行光照处理5 d,以白光处理组作为CK组,比较样品失重率、颜色、叶绿素含量、相对电导率、丙二醛含量、氧自由基吸收能力(Oxygen radical absorbance capacity,ORAC)、风味和感官评分。结果发现,绿光(该光源主要发射峰位于510~530 nm,光谱纯度为100%,强度为(2977±181.5) Lux)处理组鲜切芹菜叶的失重率(4.68%)比CK处理组降低了28.4%,并降低叶片黄化和萎蔫程度;绿光处理使鲜切芹菜叶的氧自由基吸收能力值达到485 μmol/g,比CK处理组提高了11.5%;而蓝光处理组出现叶片黄化现象,红光处理组样品风味发生显著性改变。因此,绿光处理更有利于保持鲜切芹菜叶原有的颜色、香气和感官品质。     

单色光照射对鲜青花椒叶绿素降解的实验研究

以鲜青花椒为实验材料,研究了在8种单色光照射下鲜青花椒色泽和叶绿素含量的变化,以确定各种单色光对鲜青花椒叶绿素降解的影响。研究结果表明,在整个单色光光照过程中,鲜青花椒果皮的绿色逐渐褪去,并逐渐变暗;其中,紫外光的照射对鲜青花椒色泽的影响最为明显,其次是蓝色光和黄色光;同时,鲜青花椒的叶绿素逐渐降解,其中对叶绿素a降解有显著影响的单色光依次为紫外光、蓝色光和黄色光,而对叶绿素b降解有显著影响的单色光依次为紫外光、黄色光和蓝色光。另外,青花椒果皮的色差值与青花椒体内总叶绿素的降解率相关系数为0.8380。      

轻工机械的绿色设计分析

本文简要分析了绿色设计的国际背景 ,全面介绍了绿色设计的含义、特点、关键技术及典型方法 ,给出了轻工机械实施绿色设计所需的一些特殊性工作 ,并对轻工机械绿色设计的前景进行了展望。     

绿色翡翠颜色的HSL色度学特征

目前的翡翠市场暂时未建立起评价绿色翡翠颜色的统一标准。基于HSL色度学的绿色翡翠颜色分级理论与技术,本研究拟采用机器视觉法。根据色度学原理,以HSL颜色空间模型为理论基础,在色温5 500K白光光源下,通过彩色数码摄像头采集绿色翡翠样品的色彩,对每个样品图像颜色进行HSL值分析,从而量化绿色翡翠颜色的参数指标,并将所得到的HSL数值按不同色相(H)投点到二维的SL图像上,得到翡翠绿色色彩的HSL分布区间及其色度学特征,确定绿色翡翠各种色彩类型的HSL值边界,从而区分和确定绿色翡翠的色调,划分绿色翡翠的颜色浓度和明亮度,量化绿色翡翠的色彩类型。     

彩棉与木棉的结构及热性能研究

研究棕棉、绿棉(包括浅绿棉和绿色棉)和木棉在结构和热性能上的差异。采用红外光谱、X-衍射和热重分析对这5种纤维进行了测试。研究表明:绿棉的蜡质含量较高,棕棉的蜡质含量较低,主要为脂肪醇。木棉的木质素和半纤维素含量较高,相比深绿棉,浅绿棉的软木脂含量更高,彩棉和木棉的结晶度小于白棉,在彩棉中,棕棉的结晶度和晶粒取向度要高于绿棉。木棉的结晶度和晶粒尺寸在5种纤维中最低,深绿棉的热学性能最稳定,而木棉的热降解温度最低。     

丝瓜籽中色素的提取与光热稳定性的研究

用正交实验法研究了丝瓜籽壳中色素的提取条件 ,结果表明 :该色素易溶于乙醇、乙醚、乙酸乙酯等有机溶剂。当选用体积分数 95 %乙醇为溶剂时 ,色素提取的最佳条件为 :5 0℃、固液质量比 1∶2 0、每次浸提 40min ,共浸提 3次。对色素溶液在不同波长可见光、紫外光照射及不同温度等条件下的稳定性进行了研究。发现该色素对不同波长光的稳定性不同 ,对强日光的稳定性很差 ,而对热有极好的稳定性     

不同光照条件对啤酒花中黄腐酚异构化影响

目的研究不同光照条件,如光照强度、光照时间、处理光的波长等因素对啤酒花中黄腐酚(xanthohumol,Xn)光异构化的影响。方法啤酒花样品在不同光照强度、光照时间、波长和不同颜色玻璃瓶储藏条件下处理后,于OD_(370)处测量Xn含量。结果相同功率光源的紫外光引起Xn异构化较白光显著(P0.05),白光照射Xn样品随着光照时间和光照强度的增大,Xn光异构化程度提高;相同功率光源及光照时间条件下,红光[(625±5)nm]、黄光[(590±5) nm]、绿光[(555±5)nm]、蓝光[(450±5)nm]处理引起的Xn异构化速度差异极显著(P0.01),其中蓝光最强,其次是绿光、红光、黄光;白光光源光照条件下,深棕色玻璃瓶储存对Xn的稳定性显著优于绿色、蓝色、无色玻璃瓶等(P0.05),并且深棕色玻璃瓶长期储存Xn显著优于绿色玻璃瓶(P0.05)。结论光照时间、波长及储存条件对Xn光异构化有显著的影响,且避光储存利于Xn稳定,这为含有Xn的饮品、食品、保健品等的光照或包装条件的选择提供了依据。     

不同贮藏条件下青花椒香气成分的比较

以重庆江津青花椒为原料,采用水蒸气蒸馏法提取精油,并用气相色谱-质谱联用仪(GC-MS)分析,比较在低温密封避光与室温未密封不避光2种贮藏条件下青花椒香气成分的变化。结果表明:贮藏前干青花椒挥发油含量为17.49%,贮藏后干青花椒挥发油的含量分别为15.97%(低温密封避光贮藏)和9.87%(室温未密封不避光贮藏),低温密封避光贮藏能有效延缓挥发油的损失;贮藏前后干青花椒挥发油中共鉴定出31种成分,贮藏前后共有成分24种,贮藏前后干青花椒挥发油中的主成分均为香桧烯、月桂烯、(+)-萜二烯、芳樟醇、反式橙花叔醇,但其含量因贮藏条件的不同而存在差异,不同贮藏条件下干青花椒挥发油中损失与新产生的微量成分略有差异,低温密封避光贮藏可有效保持干青花椒原有的香气。     

单色光照金枪鱼脂质和肌红蛋白氧化动力学研究

为探讨单色光照对金枪鱼生食产品脂质氧化和肌红蛋白(myoglobin,Mb)氧化的影响,优化其陈列展示光照条件,实验以大目金枪鱼(Thunnus obesus)赤身肉为研究对象,使用红、黄、绿和蓝4种单色LED(lightemitting diode)灯,以等功率、等光照强度和梯度光照强度3种方式施加光照,测定贮藏过程中金枪鱼肉硫代巴比妥酸反应产物值和高铁肌红蛋白含量变化。结果表明:贮藏期内,相较于暗室贮藏,单色光照显著促进了大目金枪鱼的脂质氧化,加速了Mb氧化;在相同光照强度下,单色光照的促氧化作用随波长减小而增大,但黄色光促氧化作用小于红色光;光照强度影响单色光促氧化作用,蓝色光和绿色光促氧化作用受光照强度的影响程度大于黄色光和红色光;脂质氧化和Mb氧化反应符合0级模式。因此,建议金枪鱼生食产品的陈列展示使用长波长的红、黄色光,避免短波长的绿、蓝色光。     

超分子双波长共振光散射法测定半胱氨酸含量

对半胱氨酸-孔雀石绿体系的反应条件进行优化,建立孔雀石绿单波长、双波长共振光散射光谱法检测半胱氨酸的新方法。结果表明：在硼砂-氢氧化钠缓冲溶液中,孔雀石绿与硼酸结合产生共振光散射,在波长285、338 nm处有2 个较强烈的共振光散射峰;加入半胱氨酸后,共振光散射更加强烈,且共振光散射强度随着半胱氨酸浓度增加而增强。在波长285、338 nm处,半胱氨酸在0.10～0.60 mg/L范围内与体系共振散射强度差值（ΔI）呈线性关系,检出限分别为10.7、13.3 μg/L;双波长叠加法的检出限为3.23 μg/L。本方法可应用于半胱氨酸护肝胶囊和酱油中半胱氨酸的含量测定,测定值的相对标准偏差（n＝6）均在3%以内,符合定量分析的要求。     

LED光质对食品用小麦芽苗生长和酚类物质累积的影响

明确不同光质对食品用小麦芽苗酚类物质累积的调节机制。小麦经避光催芽2 d后,使用LED光源的白光（W）、红光（R）、蓝光（B）、绿光（G）和黄光（Y）处理芽苗4 d,分析不同光质下小麦芽苗生长状况、总酚和酚酸含量变化及其合成酶活性和基因表达水平。结果表明：红光和黄光显著提高小麦芽苗长度和鲜/干重比,促进生长。与对照（黑暗处理）相比,蓝光、绿光和黄光处理下总酚含量增加了17.99%、18.21%和19.64%。阿魏酸、对香豆酸和咖啡酸等主要酚酸在蓝光、绿光和黄光处理下显著提高,其中香豆酸增加幅度最大,达47.36%~78.36%%。蓝光、绿光和黄光显著提高了酚类合成途径中苯丙氨酸解氨酶（PAL）、4-香豆酸-CoA连接酶（C4H）、肉桂酸4-羟化酶（4CL）活力,上调了对应的PAL、C4H和4CL mRNA水平,促进了酚类物质合成。光质对其抗氧化能力的影响趋势与酚类含量变化一致。光照处理促进小麦芽苗生长,同时通过上调酚类代谢关键酶活力及其基因表达,促进酚类物质累积,增强芽苗抗氧化活力。     

Minimizing photooxidation in pasteurized milk by optimizing light transmission properties of green polyethylene films

The effect of different amounts of transmitted green light on photooxidation in pasteurized milk was studied. Five different green films produced with combinations of pigments and additives to minimize exposure to harmful wavelengths with regard to photosensitizers (400–450 and 600–650 nm) were evaluated. In addition, a non-colored transparent film and an orange film were compared with 1 selected green film. Pasteurized milk (3.9% fat) was packed in an air atmosphere and exposed to light for 14, 20, 26, and 32 h at 4°C under the different films. Samples stored in the dark were control samples. The results showed that the most-effective green film had low overall light transmission, and also almost completely blocked light wavelengths shorter than 450 nm and wavelengths longer than 600 nm, which prevented photooxidation of riboflavin and chlorophyllic compounds. Chlorophyll degradation was highly correlated with sensory properties (coefficient of determination = 0.80–0.94). To preserve milk quality, total blocking of all visible light would be preferable. If total blocking is not feasible, then light transmission for wavelength below 450 nm and above 650 nm should be minimized (e.g., less than 5%). The newly developed green film can be used as a prototype for protection of dairy products to reduce the degradation of photosensitizers.     

绿茶啤酒的生产工艺研究

针对淡色绿茶啤酒的制作进行了研究,该产品泡沫洁白细腻,麦芽香突出,兼有绿茶风格,口味柔和,即发挥了绿茶的保健作用,又对开发绿茶资源,丰富特色啤酒市场有很重要的意义。     

The effect of LED irradiation on the quality of cabbage stored at a low temperature

The effects of light emitting diode (LED) irradiation on maintaining freshness and nutrition in cabbage during low temperature storage were investigated. Cabbage, ‘Dongdori’ was stored at 4–5°C for 18 days under white, green, blue, and red LED light. On day 15 of storage, the total chlorophyll content of cabbage was highest for green, followed by white, red, blue, and a nonirradiated control group. The vitamin C content was highest for blue, followed by white, green, red, and the control. On day 18 of storage, the total polyphenolic content in cabbage was highest for blue followed by white, red, green, and the control. LED irradiation is effective for enriching the chlorophyll, vitamin C, and polyphenol contents of cabbage stored at a low temperature and results suggest that LED colors have different effects.     

Ability of cattle to distinguish among different wavelengths of light

Eight heifers were trained using operant conditioning to press a plate to receive feed as a reward. Different wavelengths of light were the correct and incorrect stimuli. Positive and negative responses to the stimuli were registered electronically. Daily sessions of 20 min were conducted in a chamber from which external light had been excluded. A 75% correct choice was the criterion for acceptable discrimination. Ratios of correct to incorrect responses were computed. Three colors, i.e., green (535 nm), red (610 nm), and blue (450 nm), were compared pairwise during eight trials. Trial 7 was a repeat trial of green versus red and trial 8 was a comparison of green versus green. Subjects gave random response to green versus green. Five subjects distinguished red from blue: 1, 2, 3, 4, and 5 at 76, 91, 78, 88 and 81% correct choice, respectively. Three subjects distinguished blue from green: 1, 2, and 5 at 89, 88, and 85% correct choice, respectively. Three subjects distinguished green from red in a repeat trial: 1, 5, and 7 at 90, 84, and 85% correct choice, respectively. Subjects failed to discriminate these colors in the first red versus green trial. Results indicate that heifers can learn to discriminate between colors.     

一例艳绿色蓝闪石的宝石学特征

国家黄金钻石制品质量监督检验中心日常监测过程中遇见一例绿色样品,肉眼观察与翡翠、绿色软玉相似,但透射光下肉眼观察样品,颜色呈斑点状分布,无明显粒状结构。为准确确定样品矿物名称,测得其折射率为1.61～1.62,亮域显微镜下颜色呈绿色水波形态,手持分光镜下红区有吸收双线。红外反射光谱与翡翠中角闪石的谱图匹配度高,借助粉末法红外光谱,与文献对比,确定样品的主要矿物组成为蓝闪石。能量色散X射线荧光光谱分析表明样品元素组成与文献蓝闪石元素组成匹配。该样品中的Cr被初步判定为致色元素。     

不同光配比对福鼎大白茶叶片生理和主要氨基酸积累的影响

研究不同光配比对一年生福鼎大白茶树幼苗叶片生理及主要氨基酸含量的影响。在LED光谱可调人工气候箱内，设置高红光占比光源L1（红光占比71.8%）、高蓝光占比光源L2（蓝光占比62.7%）、红蓝混合光源L3（红光占比43.1%、蓝光占比29%、绿光占比27.9%）和对照白光L0（绿光占比82.1%）四种光处理，在100 μmol·m?2·s?1光子通量密度、12 h光周期条件下实施试验，采用氮平衡指数仪测定叶片生长指数，氨基酸自动分析仪测定茶氨酸、谷氨酸和天冬氨酸含量。结果表明，随着处理时间的增加，各光处理均显著增加了茶树叶片叶绿素指数和氮平衡指数，与L0相比，L1处理显著提高茶树叶片氮平衡指数（P<0.05），其次为L3处理，类黄酮指数及茶多酚含量各光处理间无显著差异（P>0.05）。与L0相比，L3和L2处理下叶片茶氨酸、谷氨酸、天冬氨酸含量显著提高（P<0.05）。综上，L3处理（红光、蓝光、绿光配比均衡）更有利于茶树叶片生长及氨基酸积累，能兼顾茶叶产量与品质，是适宜茶树栽培的LED光源。     

壳聚糖在绿茶汁澄清中的应用研究

本研究了壳聚糖对绿茶汁的澄清作用，表明壳聚糖是一种良好的澄清剂，能提高绿茶汁的透光度与稳定性，而不影响绿茶汁的主要风味物质。