Effect of solution pH of cysteine-based pre-treatments to prevent browning of fresh-cut artichokes

Fresh-cut artichokes were treated with cysteine in the form of aqueous solutions of l-cysteine hydrochloride monohydrate at 0.5% (w/v) normal pH 2.2 adjusted to different pH values with NaOH (from 2 to 7). General appearance and colour measurements during storage at 5 °C showed different degrees of suppression of darkening on cut surfaces. Cysteine pre-treatments caused an increase in the yellow index (b* value) of fresh-cut artichokes compared to untreated samples, which was more pronounced at lower pH (47.9 versus the initial value of 28.3 after 1 day). Artichokes treated at lower pH values also had a lower appearance score and higher PPO activity than artichokes treated at higher values, closer to neutrality. Starting from 3 days of storage a negative correlation between solution pH and PPO activity was also observed, that for artichokes treated with cysteine at pH 7 was lower than for control samples. l-cysteine pre-treatments did not affect total phenolic content and antioxidant activity of fresh-cut artichokes, which showed an increasing pattern after 8 days. These data may represent an important step in prevention of browning in fresh-cut artichokes.     

不同储藏温度下玻璃罐装番茄酱色泽变化的动力学研究

以新疆玻璃罐装番茄酱(24°Brix)为原料,以亮度L*值、红值a*、黄值b*、色差值△E、褐变指数和5-羟甲基糠醛(5-HMF)含量为考察指标,研究不同贮藏温度(10、25、35℃)对新疆玻璃罐装番茄酱色泽变化的影响,并在此基础上建立新疆玻璃罐装番茄酱色泽变化动力学模型,以预测玻璃罐装番茄酱褐变程度。结果表明:玻璃罐装番茄酱的色泽参数L*值、a*值、b*值变化符合一级动力学反应,色差值△E符合零级动力学反应,褐变指数和5-羟甲基糠醛含量变化在25℃和35℃下符合一级动力学反应。褐变指数、5-羟甲基糠醛含量、L*值、红值a*、黄值b*和色差值△E等各指标变化的活化能分别为74.30、65.22、45.46、55.72、102.26和64.21 kJ/mol。     

Color change of fresh-cut apples coated with whey protein concentrate-based edible coatings

The effect of antioxidant type and content alone or in combination with edible coatings for fresh-cut apples was studied. Edible composite coatings were prepared from whey protein concentrate (WPC) and beeswax (BW). Ascorbic acid (AA) at 0.5% and 1% content, cysteine (Cys) at 0.1%, 0.3% and 0.5% content, and 4-hexylresorcinol (4-hexyl) at 0.005% and 0.02% were incorporated in the formulations as antioxidants. Apple pieces were coated with the emulsion coatings and weight loss, color (CIE L*, a*, b*, and browning index (BI)) and sensory evaluation were measured during storage. Results showed that incorporation of the antioxidant to the coating reduced browning compared to the use of the antioxidant alone. 4-Hexyl was the least effective at reducing browning, even when incorporated into the WPC-based coating. Increasing AA and Cys content decreased browning of coated samples. The most effective treatments were WPC–BW-based coatings with 1% AA or 0.5% Cys. Apple pieces treated with 0.3% and 0.1% Cys aqueous solutions showed a pinkish-red appearance, whereas this effect was not shown when similar levels of Cys were incorporated into the WPC–BW-based coating. Coating application did not reduces weight loss in fresh-cut apples, probably due to the high relative humidity of the product. A sensory panel was able to discriminate between samples coated with WPC–Cys and samples dipped in Cys aqueous solution, but not between samples coated with WPC–AA and samples dipped in AA aqueous solution.     

湖南壶天山羊和湘东黑山羊肉质特性及肉成分的研究

研究旨在比较壶天山羊与湘东黑山羊的肉质性状和肉成分的差异,为进一步选育保护和开发好壶天山羊这一优质地方良种提供科学依据。试验选取6月龄壶天山羊和湘东黑山羊各10只,分别测定了失水率、熟肉率、贮存损失、生鲜肉剪切力、L*值、a*值、b*值、pH等肉质指标和肌肉中水份、粗蛋白、粗脂肪、粗灰分、氨基酸、脂肪酸、矿物质等成份。结果表明：壶天山羊与湘东黑山羊生鲜肉剪切力、L*值、a*值、b*值、pH以及肌肉中水份、粗蛋白、粗脂肪、粗灰分的含量基本一致(P＞0.05),但在甘氨酸、粗氨酸、丙氨酸、脯氨酸、苯丙氨酸、风味氨基酸、总氨基酸含量及硬脂酸甲酯、亚油酸甲酯、神经酸甲酯、C20:3n6、十七烷酸甲酯、花生四酸甲酯、C22:6ns、银杏酸、反油酸甲酯、顺-11-二十碳烯酸甲酯、榆树酸甲酯以及饱和脂肪酸、多不饱和脂肪酸、单不饱和脂肪酸含量上存在极显著差异(P＜0.01)且肌肉中铁、锰、铜的含量之间亦存在极显著差异(P＜0.01);结合原产地生态条件、体型外貌及生产性能等方面的差异,笔者认为壶天山羊和湘东黑山羊应属于不同的山羊品种。建议将壶天山羊作为一个独立的遗传资源来加以保护、研究和开发利用。     

漆树组织培养中污染与褐变的防治

漆树作为重要的经济树种,可通过植物组织培养扩繁,但在其组织培养过程中会出现严重的污染和褐变。本研究使用制霉菌素、两性霉素B、苯扎氯胺,乙醇和升汞克服污染;使用半胱氨酸,MS和White培养基克服褐变。用SPSS 12.0统计软件进行单因素方差分析和Duncan新复极差法多重比较分析,通过统计污染率、褐变率和成活率,得出最佳消毒方法以75%乙醇浸泡1 min,1%苯扎氯胺浸泡 1 min,0.1%升汞浸泡20 min效果最好,污染率为1.15%,并得出最佳防治褐变培养基以添加100 mg/L半胱氨酸的White培养基效果最好,褐变率为1.15%,并将成活率提高到97.63%。试验所建立的漆树高效、稳定的无菌体系,为后期其完整的植物组织培养体系的建立奠定了基础。     

QTL mapping for flour and noodle colour components and yellow pigment content in common wheat

Improvement of flour colour is an important breeding objective for various wheat-based end-products. The objectives of this study were to identify quantitative trait loci (QTL) for flour colour components and yellow pigment content (YPC), using 240 recombinant inbred lines (RILs) derived from a cross between the Chinese wheat cultivars PH82-2 and Neixiang 188. Field trials were performed in a Latinized α-lattice design in Anyang and Jiaozuo, Henan Province and Taian, Shandong, in the 2005–2006 and 2006–2007 cropping seasons providing data for six environments. One hundred and eighty-eight polymorphic SSR markers, rye secalin marker Sec1, STS markers YP7A for a phytoene synthase gene (Psy-A1), and four glutenin subunit markers, were used to genotype the population and construct the linkage map for subsequent QTL analysis. Two major QTL were detected for YPC, associated with 1RS (1B.1R translocation) and the Psy-A1 (7A) gene, explaining 31.9% and 33.9% of the phenotypic variances, respectively. 1RS also had large influences on Fa*, Fb*, KJ, NL*and Nb*, and Psy-A1 genes showed large effects on Fa*, Fb*, Kj, Fci, NL*, Na* and Nb*, explaining from 4.5 to 26.1% and 4.3 to 35.9% of the phenotypic variances, respectively. In addition, QTL for flour colour parameters and yellow pigment content were also detected on chromosomes 1A and 4A, accounting for 1.5–4.1% of the phenotypic variance. The genetic effect of the 1B.1R translocation on flour colour parameters was also discussed.     

小麦面粉色泽(白度)与DArT标记的关联分析

面粉色泽(白度)是评价小麦加工品质的重要指标之一。在4个环境中检测了109份矮孟牛姊妹系及其衍生系的面粉色泽(白度)参数,并利用混合线性模型分析其与覆盖小麦基因组的971个DArT (Diversity Array Technology)标记的关联性。结果显示,17个DArT标记与面粉色泽显著关联,4个标记与白度显著关联(P≤0.001)。标记wPt-1196和wPt-669693在多个环境中与色泽a*和b*关联,且效应值较大。该研究结果为小麦面粉色泽的分子标记辅助选择育种提供了参考信息。     

BA和NAA对水曲柳(Fraxinus mandshurica)未成熟胚子叶外植体褐化及体胚发生的影响

为了解析植物生长调节剂与水曲柳体细胞胚胎发生普遍伴随外植体褐化现象的关系,本研究以水曲柳未成熟合子胚子叶为外植体进行体胚发生,对细胞分裂素BA和生长素NAA的影响效应进行了探讨。结果表明,(1)当培养基中添加0.5mg/LBA和1.5mg/LNAA时,产生体胚的外植体褐化率达到91.5%;褐化外植体的体胚发生率达50.8%,而未褐化外植体的体胚发生率仅为9.6%;(2)添加NAA是水曲柳未成熟合子胚子叶外植体褐化的充分必要条件,即:无NAA存在时,未成熟合子胚子叶外植体不发生褐化,有NAA存在时才会发生褐化;只添加NAA外植体会产生褐化,但褐化程度低于同时添加BA,说明BA是促进褐化的条件;(3)添加NAA与BA是水曲柳未成熟合子胚外植体发生体胚的必要条件,即不添加生长素和细胞分裂素时无体胚发生;(4)NAA与BA的交互作用对褐化率的影响差异显著,但对体胚发生率的影响差异不显著,说明BA和NAA处理对外植体褐化的作用与对体胚发生的作用不同。由此可知:水曲柳未成熟合子胚子叶外植体的褐化和体细胞胚胎发生均受细胞分裂素BA和生长素NAA的影响,但BA和NAA分别调控了外植体的褐化和体胚的发生,与二者伴随的现象没有关系。本研究结果对进一步深入解析水曲柳体胚发生伴随外植体褐化的生物学机理提供了科学依据。     

Genotypic variation of resistance to southern stem rot of Jerusalem artichoke caused by Sclerotium rolfsii

Southern stem rot caused by Sclerotium rolfsii is a significant problem of Jerusalem artichoke (Helianthus tuberosus L.) production in Thailand. Resistant varieties are not available. The objective of this study was to investigate genetic variability of Jerusalem artichoke genotypes for resistance to stem rot caused by S. rolfsii. Ninety-one Jerusalem artichoke genotypes were evaluated under greenhouse conditions. Traits evaluated included disease score, lesion length, days to permanent wilting, plant height, shoot dry weight, and root dry weight index. Number of days from inoculation until permanent wilting was the only trait with statistically significant differences among genotypes. Based on this trait, genotypes were categorized into two distinct groups: resistant and susceptible. Genotypes that consistently expressed relative resistance to S. rolfsii included HEL 280, HEL 278, HEL 293 and JA 98. These genotypes may be useful to plant breeders as sources of germplasm for incorporating resistance to S. rolfsii into Jerusalem artichoke.     

红小豆种质资源子粒色泽及出沙率的遗传变异

对我国主产区红小豆地方品种资源中随机抽取的335份、日本25份和韩国2份材料子粒色泽和出沙率进行了鉴定评价。结果表明，红小豆粒色红度值（a^＊）平均为19．71，粒色偏灰暗，变幅为13．0—26．0；黄度值（b^＊）平均为9．58，变幅为5．2-16．8；亮度值（L^＊）平均为26．47，变幅为18．1—34．0；出沙率平均值为68．08％，变幅为61．90％-75．98％；地区间显示出明显差异。a^＊、b^＊、L^＊和出沙率4个性状均具有较高的遗传变异，但粒色a^＊、b^＊和L^＊的广义遗传力值h^2较高，出沙率的广义遗传力较低。筛选出红度值超过24．0的种质资源6份，筛选出亮度值超过30．0的种质资源16份，筛选出黄度值超过13．0的种质资源8份，筛选出出沙率高于73．5％资源8份。     

造纸法再造烟叶储存过程品质变化研究

为研究造纸法再造烟叶储存过程中的品质变化,选择两种再造烟叶产品,分析其在一年储存期内外观颜色、致香成分和感官评吸质量等指标随储存时间的变化规律;选用X-rite Color i5色差仪,测定样品L*、a*、b*值,并计算?E,考察颜色变化,用同时蒸馏萃取方法测定样品中的致香成分,按醛酮类、醇类等六大类进行综合分析,同时按广东中烟工业有限责任公司采用的打分方法对所有样品的感官评吸质量进行评定;结果表明：①两种再造烟叶产品外观颜色ΔE值随储存时间的延长明显升高,致香成分结果呈现“升高-降低-升高-降低”的趋势,感官评吸质量评价结果呈现先上升后下降的趋势;②一年储存期内,再造烟叶在2-8月期间品质较好;本研究成果表明：适宜的储存期,能够有效稳定或提升卷烟产品的感官评吸质量水平。     

砀山酥梨酶促褐变及其影响因素的研究

采用分光光度法对砀山酥梨多酚氧化酶(PPO)酶促褐变机理进行研究。通过对其所催化的邻苯二酚氧化后所得到的产物吸光度值进行测定,分析了反应时间、pH值、温度和几种抑制剂对砀山酥梨PPO活性的影响,以及研究了破碎打浆、pH值、温度、贮存时间等不同加工过程对砀山酥梨酶促褐变变化趋势的影响。结果表明,以0.1 mol/L的邻苯二酚为底物,测得砀山酥梨PPO的最适pH值为6.5,最适温度为40℃,且随着时间的延长,砀山酥梨多酚氧化酶的活性始终保持稳定;L-半胱氨酸、柠檬酸、抗坏血酸对砀山酥梨多酚氧化酶的活性均表现出抑制作用,其中以柠檬酸的效果最好;在pH值3.5-4.6,酶促褐变对总褐变指数的贡献低于非酶促褐变,且pH值越高,酶促褐变对总褐变指数的贡献越大;在4℃,室温和37℃下,酶促褐变对总褐变指数的贡献低于非酶褐变,且温度越高,酶促褐变对总褐变指数的贡献越大,温度为37℃时,随着贮存时间的延长,酶促褐变对整个褐变反应的贡献逐渐减小。     

Puroindoline基因对春小麦磨粉及馒头、面条品质的影响

以我国和CIMMYT的41份春小麦品种（系）为材料,研究了puroindoline基因型、SKCS硬度指数、出粉率、面粉灰分含量、面粉色泽（L*、a*和b*）、吸水率、总戊聚糖和水溶性戊聚糖含量以及馒头和面条品质之间的关系。结果表明,5份为Pina-D1a/Pinb-D1a类型,28份为PINA蛋白缺失（Pina-D1b/Pinb-D1a）类型,7份为Pina-D1a/Pinb-D1b类型,1份（青春533）为Pina-D1a/Pinb-D1c类型。籽粒硬度与面粉吸水率呈极显著正相关,相关系数为0.80,而与面粉亮度L*呈极显著负相关,相关系数为－0.77。Puroindoline突变型的硬度值、出粉率、吸水率及馒头重量、体积、宽度和总分均显著高于野生型,PINA蛋白缺失类型（Pina-D1b/Pinb-D1a）的籽粒硬度、面粉灰分含量、面粉a*绝对值和水溶型戊聚糖含量均显著高于Pina-D1a/Pinb-D1b类型,而馒头外观分和面条软硬度分值则显著低于后者。Pina-D1a/Pinb-D1a类型的面条L*值、L*－b*值和软硬度分值显著高于PINA蛋白缺失类型,而馒头外观颜色和面条b*值则显著低于后者。综合分析表明,Pina-D1a/Pinb-D1b类型馒头和面条品质略优于Pina-D1a/Pinb-D1a和Pina-D1b/Pinb-D1a。     

Differential inheritance of pepper (Capsicum annuum) fruit pigments results in black to violet fruit colour

Colour is a critical determinant of fruit and vegetable quality. We characterized the inheritance of black and violet immature pepper fruit colour and chlorophyll, carotenoid and anthocyanin pigments responsible for fruit colour. Segregation for black vs. violet fruit colour deviated from expectations for simple inheritance. The primary determinant of fruit colour was the concentration of chlorophyll and carotenoid pigments relative to anthocyanin concentration. Whereas anthocyanin concentration was 34% greater in violet fruit, chlorophyll and carotenoid concentrations were 20‐fold and fourfold greater, respectively, in black fruit relative to concentrations found in violet fruit. Measurement of Commission Internationale d'Eclairage (CIE) colour space scores revealed larger a* values and smaller b* values for violet fruit relative to corresponding parameters for black fruit. An additive–dominance model was sufficient to explain the variation in individual fruit pigments as well as the CIE parameter a*. Addition of additive × additive effects to the additive–dominance model resulted in the best‐fit model m[d][h][i] for L* and b* colour space parameters. For all pigment classes, significant additive effects contributed to the genetic variance for fruit colour.     

消毒剂预处理对冷鲜鸡肉货架期影响的动态监测

旨在研究屠宰加工环节中对禽肉胴体进行消毒剂预冷处理是否能够延长冷鲜禽肉的货架期。试验采用体重大小相近,健康的童子鸡个体105只,随机分成3组,分别为：对照组、含氯消毒剂处理组、含溴消毒剂处理组,在确保全程冷链运输、4℃贮存,并在第12、36、60、84、108、156、204 h采样分析,动态监测童子鸡胸肌中微生物、物理以及化学指标的变化。含氯和含溴消毒剂处理组胸肌中菌落总数数值超过1×10⁵ cfu/g和1×10⁶ cfu/g均要比对照组晚48 h;TVB-N含量超过国家最高允许值15 mg/100 g均要比对照组晚96 h;而pH值均要高于对照组,并在第204 h时超过限度值6.4;与对照组相比,含氯消毒剂处理组对于胸肌中肌苷酸、肌内脂肪含量影响较大,而含溴消毒剂处理组则影响较小;在整个4℃贮存过程中,与对照组相比,采用不同的消毒剂处理对肌肉肉质性状（如肉色、剪切力、系水力）均呈现出不同程度的影响。本次试验证实,在屠宰加工环节对冷鲜禽肉进行消毒剂预冷处理,确实能够在一定程度上延长冷鲜禽肉货架期48 h以上。     

贮藏过程中荔枝罐头褐变的初步分析

通过对一批荔枝罐头样品贮藏期间内容物指标的检测,初步分析了荔枝罐头褐变的影响因素。结果表明,氧气使褐变加速;光照对褐变无影响;可溶性固形物含量(13%)及还原糖含量相对较低(90~120g/L)的荔枝罐头褐变严重;在pH值为3.5~4.5,pH值的变化对荔枝罐头的褐变影响不显著。     

普通小麦籽粒黄色素含量的QTL分析

小麦面粉黄色度b*值是反映面粉颜色的重要指标，主要与籽粒黄色素含量有关。利用122对SSR引物、4对贮藏蛋白STS引物和10对AFLP引物组合，分析了中优9507´CA9632的71个DH系，构建了由173个位点组成的遗传连锁图，在小麦21个连锁群上覆盖2 881 cM。将该群体种植2年共计5个地点，测定籽粒黄色素和面粉黄色度b*值含量。采用复合区间作图法（CIM）进行了籽粒黄色素含量和面粉黄色度QTL分析。结果表明，面粉黄色度b*值的QTL位于染色体1DS、2DL、3A、4D、5D、6AL、6D和7AL上，其中7AL的QTL效应最大，贡献率为12.9%~37.6%；籽粒黄色素含量的QTL位于染色体2DL、3DL、4A、5A和7AL，其中7AL的QTL效应最大，贡献率为12.1%~33.9%。面粉黄色度b*值与籽粒黄色素含量共同的QTL位于7AL，与Xgwm264b紧密连锁，遗传距离分别为0~3.9 cM和0~0.9 cM。     

Methods for evaluating fruit characters and incorporation in a final index in the Norwegian pear breeding programme

Summary In the Norwegian pear breeding programme selection is based on evaluation of 20 fruit samples together with field observations of precocity, productivity and resistance to biotic and abiotic factors. Fruit weight is recorded in grams, and then transformed to a scale of 20 gram classes. Appearance, shelf life and flavour are recorded on a 0 to 9 scale, and observations of shelf life and flavour are made at 4 defined intervals following ripening at 20 °C. The final index is made by summarizing the scores of fruit size and appearance, mean score of internal breakdown, mean score of flavour, maximum score of flavour and scores of precocity, productivity and resistance. All parameters, except mean flavour, are given a weighting of one, mean fruit flavour is given a weighting of 2. Data for 160 seedlings evaluated in 1992 is presented.     

UV-C照射对鲜切淮山贮藏品质影响的研究

为了研究鲜切淮山的保鲜方法,保证其良好的感官品质,延长货架期,用不同剂量(0.5、1.0、1.5、3.0、4.5、6.0 kJ/m~2)的254 nm短波紫外线分别照射60、120、180、360、540、720 s。通过测定色差值、褐变度、硬度及失重率探究其保鲜效果。研究发现:3 kJ/m~2的照射剂量能明显抑制淮山的褐变,保持色差值L*和硬度,减小淮山切片的失重率,说明UV-C对鲜切淮山有明显的保鲜效果。