柑桔类果实在储运中的化学防腐

柑桔类果实采后的主要病害有:蒂腐病(stem-end rot)——由色二孢菌(Diplodianatalensis)或拟茎点霉菌(phomopsis citri)引致;黑腐病(blackrot)——由链格孢菌(Alternaria citri)引致;以及伤口性的病害如绿霉病(green mold)——由绿霉菌(penicillium digitatum)引致、青霉病(blue mold)—由青霉菌(Penicillium italicum)引致,酸腐病(sour rof)——山白地霉菌(Geotrichum candidum)引致;在雨季收获的     

河南省烟草赤星病病原鉴定

为明确河南省烟草赤星病病原菌的种类,从河南省不同烟区采集烟草赤星病典型病斑,分离病原菌并且做致病性测定,对确定为病原菌的菌种按国际标准方法进一步做形态和分子鉴定。结果显示分离到的85株菌株中60株被证明是烟草赤星病病原菌,从形态学上鉴定为三个种,分别是链格孢Alternaria alternata、长柄链格孢Alternaria longipes和鸭梨链格孢Alternaria yaliinifciens。其中鸭梨链格孢Alternaria yaliinifciens引起烟草赤星病属首次报道。三个种的代表菌株的5.8S rDNA ITS基因序列间及已报道的链格孢Alternaria alternata,长柄链格孢Alternaria longipes和鸭梨链格孢Alternaria yaliinifciens的5.8S rDNA ITS区均没有较大差异,证明该基因在链格孢小孢子种间较保守,不适合区分这些链格孢种。     

壳聚糖和壳寡糖对四种青霉病菌生长和病害控制的比较研究

在离体和活体条件下,开展了壳聚糖与壳寡糖对四种同属不同种青霉菌菌丝与孢子抑制作用及病害防治的研究。结果表明:离体条件下,随着壳聚糖与壳寡糖浓度的升高,对四种青霉菌菌丝与孢子的抑制效果逐渐增强,总体上壳聚糖的抑菌效果要好于壳寡糖。其中,产黄青霉菌(Penicillium chrysogenus Thorm)对壳聚(寡)糖的敏感性在四种青霉菌中最强,指状青霉菌(P.digitatum)敏感性最弱。在柑橘果实实验中,壳聚糖或壳寡糖对柑橘指状青霉病害控制效应最弱,对产黄青霉病害控制效应最强。在四种青霉中,壳聚(寡)糖对产黄青霉的抑制作用和病害控制最为明显,且壳聚糖效果好于壳寡糖。     

吉林省和黑龙江省烟草赤星病病原鉴定

为明确吉林省和黑龙江省烟草赤星病病原菌的种类,对吉林省15个烟区和黑龙江省7个烟区的烟草赤星病病原菌进行了分离鉴定,共分离获得312株致病菌株。通过形态学和分子生物学鉴定,共鉴定出4种链格孢属真菌,其中链格孢（Alternaria alternata）230株,细极链格孢（Alternaria tenuissima）78株,鸭梨链格孢（Alternaria yaliinficiens）2株,长柄链格孢（Alternaria longipes）2株。其中吉林省烟区鉴定出了链格孢、细极链格孢和鸭梨链格孢3种,黑龙江省烟区鉴定出了长柄链格孢、链格孢和细极链格孢3种。两个省区的优势种均为链格孢。此外,本试验利用5种基因序列片段（ITS、GDP、ACT、EF、RPB2）进行烟草赤星病菌的分子生物学鉴定,其中GDP基因仅能鉴定出链格孢和细极链格孢2种,RPB2基因能鉴定出4种链格孢,而ITS、EF、ACT基因序列比较保守,不适合区分这些链格孢种。本研究明确了吉林省和黑龙江省烟区引起烟草赤星病的病原菌种类,为下一步的定向防控奠定了基础。     

鲜切苹果腐败霉菌的分离鉴定及致腐力的研究

对引起鲜切苹果腐败的霉菌进行分离鉴定并通过活体实验比较致腐能力。从鲜切苹果中分离13株霉菌,通过形态学鉴定方法分为5个属,其中青霉菌属(Penicillium)7株,曲霉属(Aspergillus)1株,枝孢属(Cladosporium)3株,枝顶孢属(Acremonium)1株,链格孢属(Alternaria)1株。根据青霉菌在CA、CYA、G25N培养基上的特征及镜检观察,将所分离的青霉菌鉴定为5种:皮落青霉(P.crustosum),扩展青霉(P.expansum),米舒青霉(P.miczynskii),橘灰青霉(P.aurantiogriseum),鲜绿青霉(P.viridicatum)。活体实验进行腐败与非腐败霉菌的分类,得到腐败霉菌有5种,分别为鲜绿青霉、扩展青霉、皮落青霉、互隔交链格孢霉(A.alternata)、黑曲霉(A.niger);非腐败霉菌有5种,分别为橘灰青霉、地生枝顶孢(A.terricola)、球孢枝孢(C.sphaerospermum)、枝状枝孢(C.cladosporioides)和米舒青霉。5种腐败霉菌的致腐能力从大到小依次为:皮落青霉、扩展青霉、鲜绿青霉、互隔交链格孢霉、黑曲霉。     

苯乳酸抑制链格孢霉作用靶位的分析

以从自然腐败的樱桃上分离的链格孢霉（Alternaria sp.）LD3.0086为指示菌，研究苯乳酸对链格孢霉的主要抑制作用靶位。应用分光光度法测定苯乳酸对链格孢霉的最小抑菌浓度，通过卡尔科弗卢尔荧光增白剂染液（calcofluor white，CFW）染色观察苯乳酸对菌丝顶端生长的破坏作用，利用扫描电子显微镜和透射电子显微镜观察链格孢霉的超微结构变化，通过测定苯乳酸作用前后链格孢霉上清液中N-乙酰葡萄糖胺质量浓度变化研究苯乳酸对菌丝细胞壁的破坏作用，应用荧光双染色法观察苯乳酸对链格孢霉菌丝细胞膜的损伤作用。结果表明，12.5 mmol/L的苯乳酸能有效抑制链格孢霉的生长；与对照组（无菌水处理）相比，苯乳酸处理后链格孢霉顶端生长细胞无明显形变，经12.5 mmol/L苯乳酸处理的链格孢霉上清液中N-乙酰葡萄糖胺质量浓度基本不变；苯乳酸处理24 h，链格孢霉菌丝细胞壁表面无明显损伤，细胞内结构发生明显变化；苯乳酸短时间（4 h）处理链格孢霉，菌丝细胞膜仍较为完整，加入苯乳酸较长时间（8 h）后细胞膜发生破裂。综合分析可知，苯乳酸对链格孢霉的主要作用靶位应不是菌丝体的细胞壁和细胞膜，而是在菌丝体内部，通过破坏菌丝内部细胞器结构或引起细胞内的生化反应，从而抑制链格孢霉的生长和繁殖，发挥抑菌活性。     

丁香酚对蓝莓链格孢霉的抑制作用

以从自然腐败的蓝莓上分离得到的链格孢霉(Alternaria sp.)为对象,研究丁香酚对链格孢霉的抑菌作用及机理。测定了不同质量浓度丁香酚对链格孢霉菌丝生长和孢子萌发的影响;通过扫描电子显微镜和透射电子显微镜观察链格孢霉的形态和结构,碘化丙啶染色观察丁香酚对链格孢霉菌丝细胞膜的影响并测定链格孢霉菌丝细胞壁相关酶活力的变化。结果表明:丁香酚质量浓度为0.3 mg/mL时能够完全抑制链格孢霉菌丝的生长及孢子萌发;与对照组相比,经0.3 mg/mL丁香酚处理的链格孢霉的孢子和菌丝严重变形、表面出现大量褶皱,胞内物质流失,无完整细胞器;菌丝经碘化丙啶染色后出现红色荧光,胞外可溶性蛋白质量浓度和电导率分别是对照组的1.18倍和8.02倍,几丁质酶和β-1,3-葡聚糖酶的活力分别提高2.37倍和50%。综合分析可知,丁香酚可以破坏链格孢霉细胞壁,改变细胞膜通透性,进而抑制链格孢霉的生长代谢及其繁殖,从而发挥抑菌活性。     

银杏外种皮提取物对苹果链格孢霉的抑制作用

为研究银杏外种皮提取物（Ginkgo biloba exocarp extract,GBEE）对苹果链格孢霉的抑制作用,采用乙醇提取法和水提取法提取银杏外种皮活性成分,并采用菌丝生长速率法,测定银杏外种皮提取物对苹果链格孢霉的抑制效果,研究银杏外种皮乙醇提取物对苹果链格孢霉孢子萌发和芽管伸长的影响。通过测定电导率,蛋白质、核酸的渗漏量,细胞膜损伤程度以及抗性相关酶活性来进一步研究抑制行为。GBEE的抑菌作用呈浓度依赖性,水溶性提取物于1 200 mg/L抑菌率达到16.94%,乙醇提取物于1 200 mg/L抑菌率达到61.39%,约为水溶性提取物的3.6倍。银杏外种皮乙醇提取物使苹果链格孢霉菌体细胞膜通透性增加,膜脂过氧化程度加剧,丙二醛（malondialdehyde,MDA）和H2O2含量升高,胞内核酸、蛋白质外泄,抑制抗性相关酶活性,通过光学显微镜观察到乙醇提取物处理组的链格孢霉菌无细胞壁间隔。乙醇提取物的抑菌效果比水提物好,通过破坏苹果链格孢霉菌的细胞膜完整性和抑制抗性相关酶活性来达到抑菌目的。     

黑腹果蝇和斑翅果蝇对‘玫瑰香’葡萄酸腐病的影响

为了明确葡萄采收期致腐病菌与黑腹果蝇、斑翅果蝇的关系,模拟田间条件,将8种与葡萄酸腐病相关的真菌分别与两种果蝇联合侵害葡萄果实,观察葡萄的发病率与病情指数。结果表明,黑腹果蝇和8种真菌在有损伤‘玫瑰香’葡萄上的发病率均为100%;黑腹果蝇和真菌联合侵害初期,黑腹果蝇显著降低桔青霉、层生镰刀菌、青霉菌、米曲霉的病情指数;但在侵染第7天时,8种真菌的病情指数在黑腹果蝇的取食后均显著增加。在侵染新鲜完整葡萄的初期,尖孢枝孢菌和黑曲霉的发病率明显低于斑翅果蝇;斑翅果蝇的取食增加桔青霉、层生镰刀菌、青霉菌、细极链格孢和棘孢曲霉的病情指数,降低黑曲霉的发病率。因此,黑腹果蝇促进8种真菌的发育与侵染,斑翅果蝇的产卵与取食为桔青霉、层生镰刀菌、青霉菌、细极链格孢和棘孢曲霉5种真菌侵染新鲜葡萄创造更为有利的条件。     

微波和臭氧处理对果脯的杀菌效果及品质变化分析

该研究探究了微波与臭氧处理对四种果脯优势霉菌芽枝状枝孢霉（Cladosporium velox）、暗黄青霉（Penicillium citreonigrum）、菌核青霉（Penicillium sclerotiorum）、细极链格孢（Alternariate nuissima）的抑菌效果及果脯理化品质的影响。结果表明,微波与臭氧处理均可显著抑制霉菌生长,抑菌率随微波功率,微波时间,臭氧通入时间增加而增大。当微波功率为630 W,微波时间为20 s时,四种霉菌抑菌率最高均达到100%。当通入臭氧10 min时,抑菌效果最佳,芽枝状枝孢霉、暗黄青霉、菌核青霉、细极链格孢的抑菌率分别达到73.17%、80.87%、83.33%、91.02%。微波和臭氧处理均对果脯理化品质具有一定影响,随着随微波功率,微波时间,臭氧通入时间增加,果脯水分含量、水分活度、总糖含量和色差值均呈下降趋势。研究结果为微波和臭氧技术在果脯杀菌中的应用提供了理论支撑和参考依据。     

Some chemical options for the control of hard to cook and the associated browning in boiled cowpea (V. unguiculata)

Long cooking time is a problem militating against a wider dietary exploitation of the high protein contents of many grain legumes. Addition of CaHCO₃ (calcium bicarbonate) and a crude rock salt of carbonates (kaun) are the traditional methods of alleviating this problem in most Nigerian homes. However, this treatment also enhances browning; hence it is important to look for alternatives to the carbonates. The effects of some salts and organic acids on the cooking quality of a white variety of cowpea (V. unguiculata) was studied. The cookweights increased by 13.5, 23.8 and 28.7% with addition of hydrogencarbonate, carbonate and hydroxide of sodium, and by 16.65, 21.1 and 21.5% with addition of the hydrogencarbonate, hydroxide and carbonate of potassium. Addition of chlorides of sodium, potassium and calcium decreased the cookweight by 0.5, 8.5 and 13.5%, respectively (p>0.05). Addition of the carbonates of sodium and potassium increased the browning of the grains (p<0.01), but addition of organic acids and chloride salts of sodium, potassium and calcium, respectively, reduced the browning (A430 nm) (p<0.01). Citric acid was suggested as an alternative to the traditional use of carbonates for boiling cowpea.     

Synergistic effects of combining biocontrol agents with silicon against postharvest diseases of jujube fruit

The synergistic effects of biocontrol yeasts Cryptococcus laurentii and Rhodotorula glutinis combined with silicon (Si) against Alternaria alternata and Penicillium expansum molds were investigated in jujube fruit (Chinese date, Zizyphus jujuba) stored at 20 and 0 degrees C, respectively. Combinations of C. laurentii and R. glutinis at 5 x 10(7) cells/ml with 2% Si was most effective in controlling the diseases caused by A. alternata and P. expansum on jujube fruit stored at 20 degrees C. When fruits were stored at 0 degrees C, combining C. laurentii and R. glutinis with Si was as effective against P. expansum as was Si or the yeasts applied alone and was more effective in controlling A. alternata. Si may have a fungistatic effect by directly inhibiting pathogen growth, but it did not greatly influence the growth of the antagonists.     

苹果腐败霉菌的拮抗酵母菌筛选鉴定及拮抗机理初探

从苹果果皮中筛选出对引起苹果采后病害的扩展青霉(Penicillium expansum)、互隔交链格孢霉(Alternaria alternata)和黑曲霉(Aspergillus niger)具有拮抗作用的酵母菌,并初步研究其拮抗机理。结果表明:筛选得到两株可以同时拮抗三种腐败霉菌的拮抗酵母菌Y4和Y9,根据酵母菌菌落性状、生理生化特征并结合分子生物学的分析结果,鉴定为Candida railenensis和Aureobasidium pullulans,其中A.pullulans为类酵母真菌。C.railenensis的最佳拮抗浓度为109 CFU/mL,对P.expansum、A.alternata和A.niger的菌丝生长、孢子萌发和芽管生长均有显著(p<0.05)的抑制作用。扫描电镜观察到C.railenensis能够包围和吸附腐败霉菌孢子,与它们竞争营养与空间,此外还能够吸附P.expansum菌丝体与其直接作用。C.railenensis的主要抑病机理是营养与空间竞争,并且其生防效果的发挥是多种方式共同作用的综合结果。     

碱性盐在生鲜湿面保鲜和品质调控中的应用

为深入探讨碱性盐对生鲜湿面保质期和品质特性的影响,选用不同添加量的5种碱性盐（碳酸钠、碳酸钾、磷酸三钠、磷酸三钾及碳酸氢钠）制作生鲜面条,通过将菌落总数、L*值和表观状态作为表征生鲜湿面变质的可视化参数,确定不同碱性盐在生鲜湿面中的最适添加量;通过测定贮藏期间生鲜湿面pH值、面团流变学特性、面条烹饪特性和质构特性、感官评价并用扫描电镜观察微观结构综合分析碱性盐对生鲜湿面品质的影响规律。结果表明：与对照组相比,碱性盐添加可有效抑制生鲜湿面中微生物的生长,添加2.0%的碳酸钠,能够将生鲜湿面保质期延长2.5倍,碱性盐均使面条呈现明亮的浅黄色外观,明显改善其表观状态,确定碳酸钠在生鲜湿面中最适添加量为1.0%,其余4种碱性盐最适添加水平均为1.5%。在贮藏期间,添加碱性盐调控且稳定面条pH值,显著增强面团吸水率和拉伸特性、降低面团弱化度,且延伸度随着醒发时间的延长而降低;增加了生鲜湿面蒸煮损失,降低面条吸水率、提高硬度、拉伸强度、弹性、黏性和适口性。扫描电镜发现,碱性盐的添加能够加强生鲜湿面中蛋白质和淀粉的交联程度,从而形成更加连续致密的面筋网络结构。其中碳酸钠对生鲜湿面品质改善效果最为突出...     

碳酸氢钾和氯化钠对烟草转化株烟碱转化的诱导作用

以白肋烟TN90高转化株为材料研究了无机盐处理烟株早期叶片对烟碱转化的诱导作用及机理。结果表明,1.2%的碳酸氢钾水溶液和1.2%的氯化钠水溶液均具有显著的诱导转化株早期叶片烟碱转化作用,碳酸钠效果较差。比较碳酸氢钾处理、氯化钠处理分别对常规TN90品种烟株转化株的早期鉴定结果和自然晾制后烟叶的烟碱转化率发现,采用2种无机盐鉴别出的转化株均包括了所有在自然晾制后产生的转化株,且还可鉴别出一些在正常晾制条件下不能有效鉴别的低转化株;早期测定的烟碱转化率一般高于烟叶自然晾制后的烟碱转化率,有利于提高鉴定的准确性和有效性。碳酸氢钾可显著促进叶片内源乙烯的释放,在处理溶液中添加10-4mol/LAVG抑制乙烯的合成可逆转碳酸氢钾对烟碱转化的诱导。     

Effects of potassium buffers on feed intake in lactating dairy cows and on rumen fermentation in vivo and in vitro

Twenty-four Holstein cows were used to compare acceptance of concentrates and complete rations containing 1) no buffer, 2) 1.8% potassium bicarbonate, 3) 1.2% potassium carbonate, or 4) 1.5% sodium bicarbonate in the concentrate. When concentrate and a forage blend were offered separately (comparison period 1), concentrate intake did not differ among treatments, but forage blend consumption and complete ration intake was greater with the potassium carbonate ration (comparison period 2). Rumen pH did not differ, but urine pH was higher in cows fed complete rations containing buffers. Cows fed potassium carbonate had higher milk fat percentages than cows fed sodium bicarbonate during the first comparison period and higher than controls during the second comparison period and produced more 3.5% fat-corrected milk and solids-corrected milk than cows fed sodium bicarbonate in both comparison periods. Milk protein percentage was lower in cows fed potassium carbonate diets as compared with those fed sodium bicarbonate diets, but total protein production was similar. In three continuous culture in vitro trials, potassium carbonate maintained fermenter pH comparably to sodium bicarbonate, and total volatile fatty acid and acetate production were similar.     

Anionic salts in the prepartum diet and addition of sodium bicarbonate to colostrum replacer, and their effects on immunoglobulin G absorption in the neonate

The objectives of this experiment were to determine whether feeding anionic salts to prepartum Holstein cows affected their calf's colostral IgG passive transfer and whether adding sodium bicarbonate to a colostrum replacer (CR) would increase the efficiency of IgG absorption. Forty Holstein cows and their resulting calves were assigned to a 2 × 2 factorial arrangement of treatments in a randomized complete block design based on expected date of calving. Three weeks before the projected due date, cows were placed on 1 of 2 treatments: a diet without anionic salts (dietary cation-anion difference of +77 mEq/kg) or a diet with anionic salts (dietary cation-anion difference of −100 mEq/kg). Within 45 min after birth, all calves received 1 dose of a commercially available CR (132 g of IgG) without or with supplemental sodium bicarbonate (19.5 g/dose). A half-dose of CR (66 g of IgG) and sodium bicarbonate (9.75 g) was fed at 6 h of age. Calves received milk replacer at 12, 24, 36, and 48 h. Blood samples were obtained from calves at 0, 6, 12, 24, and 48 h and were analyzed for IgG concentration. Cows fed the diet supplemented with anionic salts had lower DMI on d 8, 5, 4, and 1 and lower urine pH 2 and 1 wk before parturition compared with cows fed the diet without supplemental anionic salts. Calves born from dams receiving anionic salts had similar IgG concentrations (15.1 vs. 14.4 g/L) and apparent efficiency of absorption values (29.2 vs. 28.2%) compared with calves born from dams not fed anionic salts. Calves receiving supplemental sodium bicarbonate in the CR had higher serum IgG concentrations at 12 (14.4 vs. 12.0 g/L), 24 (16.3 vs. 13.2 g/L), and 48 h (14.6 vs. 11.2 g/L) and higher apparent efficiency of absorption values (31.2 vs. 26.1%) than calves that did not receive sodium bicarbonate in the CR. Calves receiving sodium bicarbonate also had greater area under the curve values for IgG absorption compared with calves not receiving sodium bicarbonate. There was a trend for an interaction with calves born from dams fed anionic salts having a greater area under the curve when fed supplemental sodium bicarbonate. Of the 40 calves in the study, 90% obtained adequate passive transfer (serum IgG ≥10 g/L). This study indicates that feeding anionic salts to the dam has no effect on passive transfer, whereas adding sodium bicarbonate to the CR increased IgG uptake in calves.     

Use of Bicarbonates for Microbial Control and Improved Water-Binding Capacity in Cod Fillets

Dipping cod fillets in ammonium or sodium bicarbonate solutions markedly reduced microbial growth compared to untreated samples after 8 days at 4°C. Total plate counts, proteolytic bacteria and H₂S-producing bacteria were inhibited. Mixing ammonium- and sodium bicarbonates at selected ratios maintained the preservative effect while reducing the ammonia odor. The treated fish had improved texture and moisture retention by both objective and subjective testing but had significantly lower aroma and overall acceptability scores from sensory evaluation.     

Gas sources in chemical leavening and other baker’s yeast substitutes: lessons from patents and science

Baker’s yeast produces carbon dioxide during dough fermentation, which gives bakery foods with expanded volume. This review covers gas sources other than baker’s yeast according to information disclosed in patents and supported by scientific literature. Inventors had more interest in gas injection in dough, mainly carbon dioxide, than gas-releasing agents available in chemical leavening, so-called baking powder, with 58 and 43 patented inventions, respectively. For chemical leavening, 20 gas-releasing agents were proposed, including 11 patented and 9 non-patented agents like sodium bicarbonate, the most popular. Other gas-releasing agents included miscellaneous salts of carbonate and bicarbonate (ammonium; calcium; magnesium; potassium) as well as compounds like hydrogen peroxide and, more recently, glutamic acid. Coatings were patented to protect sodium bicarbonate towards moisture and delay its action in dough. Recent trends include aerosol dough and flavourful sodium-free gas-releasing agents.     

两种兔耳草提取物的体外抑菌作用

短管兔耳草(Lagotis brevituba Maxim)和短穗兔耳草(Lagotis brachystachy Maxim)在传统藏药中具有抑菌消炎的功效。采用琼脂孔扩散法和96孔培养板对倍稀释法测定了这两种植物不同极性溶剂逐级提取物对4种采后真菌和4种腐败细菌的体外抑菌率和最低抑制浓度。结果表明:在供试真菌中,短管兔耳草提取物对F.semitectum和P.expansum具有抑菌活性,短穗兔耳草提取物对P.expansum和A.alternate具有抑菌活性。两种植物的提取物对供试细菌的抑菌活性整体上较强,短管兔耳草提取物对S.aureus和P.fluorescence有抑菌活性,而短穗兔耳草提取物对S.aureus,E.coli,B.subtilis和P.fluorescence都有抑菌活性。提取物对细菌的最低抑菌浓度最低可达0.05g/mL。结论:这两种植物的提取物具有较广的体外抑菌谱和较强的抑菌活性。