The effects of handling on chip color and sugar content of potato tubers

Color of chips made from potatoes (Solanum tuberosum L.) subjected to handling treatments was darker than of non-handled tubers in nine of ten experiments. ‘Monona’ and ‘Rosa’ appeared to be more vulnerable to the adverse effects of handling than were ‘Kennebec’ and ‘Norchip,’ but all cultivars were affected. Levels of fructose and glucose were elevated by handling. Sucrose also increased in all cultivars except ‘Kennebec.’ The handling effect was most noticeable early (December) or late (March or April) in the storage season. The effect of chilling did not appear to be intensified by handling.     

Glycoalkaloid levels in potato tubers and leaves after intermittent plant exposure to ozone

Irish potato vines of ‘Norland’ and ‘Kennebec’ cultivars were exposed to 387 μ/m³ ozone for 3 hr once every wk throughout their growth. Tubers of ‘Norland’ and ‘Kennebec’ were harvested at 120 and 140 days, respectively, from exposed and non-exposed plants. The experiment was conducted in 1977 and again in 1978. Ozone induced severe foliar injury to ‘Norland’ and slight injury to leaves of ‘Kennebec’ Tubers from ozone treated plants displayed a significant reduction (0.35 mg TTGA/100 g fresh weight tuber tissue) in tuber total glycoalkaloids (TTGA) when expressed on a fresh weight basis. However, since differences were not detected for TTGA on a dry-weight basis, the fresh-weight TTGA differences may only reflect variations in moisture content. In a separate experiment, both ‘Norland’ and ‘Kennebec’ were exposed to 488 μg/m³ ozone for 3 hr when the plants were 18 days old. When leaves were harvested three days later, no significant differences were detected between leaf total glycoalkaloid (LTGA) levels of treated and nontreated plants.     

成熟期不同橄榄品种（系）果实代谢组及其差异

橄榄果实风味独特,富含多酚、黄酮、氨基酸等多种生理活性物质,这些物质与其风味品质关系密切。目前对橄榄果实代谢物进行系统研究的报道较少,为解析橄榄果实的主要代谢成分并对3个品质类型存在差异的品种（系）（‘长营’‘檀香’‘灵峰’）进行比较,以期为橄榄果实品质形成、优良品种选育等研究提供理论基础。采用超高效液相色谱-串联质谱（UPLC-MS/MS）的广泛靶向代谢组技术,测定3个橄榄品种（系）成熟期果实代谢物,并结合多元统计分析方法及3个品种（系）果实总酚、总黄酮、木质素含量数据进行分析,结果表明：‘檀香’总酚、总黄酮含量最高;‘灵峰’总酚、总黄酮及木质素含量最低;‘长营’总木质素含量则很高,与其化渣差的特点相吻合。利用广泛靶向代谢组学技术共检测出黄酮、酚酸类、氨基酸及其衍生物、有机酸、脂质、核苷酸及其衍生物、鞣质、糖及醇类、木质素和香豆素等13类524种代谢物,其中黄酮类代谢物数量最多,主要为槲皮素类、木犀草素类和山奈酚类。各品种（系）代谢物差异显著,主要的差异代谢物为黄酮类、酚酸类和氨基酸及其衍生物。‘长营’相比‘檀香’存在161种差异代谢物（上调代谢物116种、下调代谢物45种）,‘檀香’相比‘灵峰’存在164种差异代谢物（上调代谢物51种、下调代谢物113种）;‘长营’相比‘灵峰’存在146种差异代谢物（上调代谢物51种、下调代谢物95种）。差异代谢物KEGG通路富集分析发现,3个品种（系）中,‘檀香’的黄酮代谢及氨基酸代谢最为活跃,积累更多的槲皮素类、木犀草素类、山奈酚类、丙氨酸、丝氨酸、组氨酸、苯丙氨酸、酪氨酸等黄酮及氨基酸类物质;‘灵峰’较‘长营’的黄酮代谢相对较弱,黄酮类物质积累相对较少,这可能是造成‘檀香’橄榄风味更为浓厚,而‘灵峰’橄榄风味较为清甜的原因之一。     

Investigations into the mode of resistance of potato tubers toFusarium roseum ‘Sambucinum’

In a histological study comparing tuber resistance of potato clone B7200-33 and susceptible variety “Russet Burbank” toFusarium roseum ‘Sambucinum’, the formation of suberin and wound periderm was found to be an important resistance mechanism. In B7200-33 tubers a continuous suberin layer was formed whereas in ‘Russet Burbank’ tubers the suberin was formed in clumps so that the pathogen easily could invade the tissue between the clumps but not through a continuous layer. Wound periderm also was formed at a more rapid rate in B7200-33 than in ‘Russet Burbank’ tubers thereby “walling off” the pathogen and reducing decay.     

普洱产区咖啡干香感官特征解析及杯品质量分析

以云南普洱产区咖啡为原料,利用顶空固相微萃取-气质联用技术(HS-SPME-GC/MS)和香气活度值法(odor activity values,OAVs)确定咖啡中特征干香组分,明确其感官风味特征,并邀请专业咖啡质量品鉴师团队评价杯品品质.结果表明:普洱产区14个区域咖啡中共有干香组分78种,特征感官风味组分(OAV...     

Contamination of soil and transmission of seedborne potato dry rot fungi (Fusarium spp.) to progeny tubers

A survey of selected potato soils in Maine was made to determine the species and populations ofFusarium spp. present.Fusarium solani ‘Coeruleum’ was most often isolated butFusarium roseum ‘Sambucinum’ was not recovered from any soil. Crops or cropping sequences in general showed no direct relationship to observed Fusaria populations or tuber dry rot. Field studies were conducted to determine the effect ofFusarium contaminated seed on soil and daughter tuber contamination. Whole and cut seed were inoculated withFusarium roseum ‘Sambucinum’ and half of each lot treated with thiabendazole (1500 ppm) to controlFusarium seed decay. Soil populations ofF. roseum ‘Sambucinum’ were higher near plants produced from non-treated, cut seed tubers. No increase inFusarium populations was found between plants or near plants produced from whole or thiabendazole treated seed. Daughter tuber contamination was greatest from plants produced from non-treated contaminated cut seed, and lowest from whole or treated seed. Whole non-treated seed produced daughter tubers with contamination equal to treated whole seed. This indicates that the use of whole seed could be a method to reduce daughter tuber contamination and reduce reliance on chemical treatments. Cut seed contaminated withFusarium spp. is an important source of daughter tuber contamination which can result in a high amount of tuber dry rot in storage.     

利用茉莉花茶香气指数鉴定其窨制品质及构建决策树模型

在检测分析32个茉莉花茶样挥发性成分的基础上,结合文献引证分析了茉莉花茶、茉莉花、茉莉花干和茶坯的茉莉花茶香气指数(Jasmine tea flavor index,JTF index)。结果表明,JTF值与茉莉鲜花的芳香物质整体挥发水平存在相关性;针对29种特征挥发物对32个茉莉花茶茶样进行主成分分析(Principal component analysis,PCA),得到不同窨制品质的显著聚类特征,推断JTF指数与29种特征挥发物的缺失可作为茉莉花茶窨制品质判定指标。进一步构建这32个茉莉花茶茶样窨制品质的决策树鉴定模型(判别准确率为93.8%),确定特征挥发物的缺失峰数(节点为4)和JTF值(节点为0.915)为判定节点,证实了JTF值与29种特征挥发物的缺失可应用于茉莉花茶窨制品质鉴定与掺假判别,并且建立决策树模型,能够快速、准确检测出不同窨制品质的茉莉花茶,尤其为掺假(如添加香精)等检测提供依据。     

拉面制作过程和产品感官评价方法的评估

为给拉面质量评价、拉面用粉标准的制定提供感官评价方法,采用走访询问、现场调查和网络交流等方式,收集拉面师傅对实验室制定的拉面制作过程感官评价方法的意见和建议;以餐饮市场常用小麦粉为样品原料,在兰州市和北京市分别开展消费者对拉面产品感官评价要素重视程度的问卷调查,分析、评估和确定了拉面制作过程和产品感官评价方法。88.89%的拉面师傅认为,所制定的拉面制作过程和感官评价方法可以概括拉面制作的整个过程,其对评价指标的重视程度依次为"和面难易程度及面团软硬程度""断条扣数及均匀性""跐面力度及黏手程度""醒发后面团色泽"="拉伸力大小";制定的拉面制作工艺可使大多数小麦粉满足加工工艺要求。消费者对产品感官评价要素的重视程度由高到低为弹性色泽硬度光滑性表观黏性;消费者完全可以区分出拉面用小麦粉的质量优劣。本研究制定的方法可用于拉面制作过程和产品感官质量的评价。在百分制评价体系中,拉面制作过程感官评价赋值分别为"和面难易程度及面团软硬程度"35分、"断条扣数及均匀性"20分、"跐面力度及黏手程度"15分、"醒发后面团色泽"15分、"拉伸力大小"15分;拉面产品消费者感官评价赋值分别为"弹性"30分、"硬度"20分、"色泽"20分、"表观性状"10分、"光滑性"10分、"黏性"5分、"食味"5分。     

番石榴发育期生物活性物质研究

番石榴风味独特,营养丰富。本研究以‘珍珠’番石榴和‘水晶’番石榴为试材,研究番石榴果皮和果肉中 生物活性物质含量及其与抗氧化能力关系。结果表明：番石榴果皮和果肉中,‘珍珠’番石榴的总酚、类黄酮、酚酸、 单宁含量均高于‘水晶’番石榴;番石榴的果皮和果肉发育过程中总酚、类黄酮、酚酸、叶绿素及类胡萝卜素含量均 呈下降趋势;番石榴果皮中生物活性物质含量高于果肉,且果皮抗氧化能力高于果肉;在生物活性物质与总抗氧化能 力的相关性方面,总酚含量相关性最高。本研究结果可为番石榴加工产品开发提供理论和实践基础。     

The effect of potato virus X on susceptibility of potato tubers toFusarium roseum ‘Avenaceum’

Potato virus X (PVX)-free and mild PVX-infected tuber lines originating from the same Katahdin clone were compared for susceptibility to tuber rot incited byFusarium roseum (Lk.) Synd. and Hans. ‘Avenaceum’. The effect of interval between top-kill and harvest on development ofFusarium tuber rot was also determined. A series of tubers from both PVX-free and PVX-infected tuber lines was either (i) mechanically bruised and inoculated by immersion in a spore suspension ofF. roseum ‘Avenaceum’, (ii) mechanically bruised but not inoculated, (iii) inoculated only or (iv) neither bruised nor inoculated. Tubers from all treatments were then stored at temperatures of 18–21 C (65–70 F) for a 3-week period prior to being placed at 4 C (39 F) for the remainder of the storage period. The amount of rot was determined after a 5–6 month storage period at the latter temperature. In a 4-year study PVX-free tubers were significantly (1% level) more susceptible to infection byF. roseum ‘Avenaceum’ than tubers infected with mild PVX. PVX-free tubers left in the ground for 2 or 3 weeks after top-kill were significantly (1% level) more susceptible toFusarium dry rot than those infected with the virus; however, there was no significant difference in disease incidence between PVX-free and PVX-infected tubers when harvested 4–5 weeks after top-kill. Tubers, both PVX-free and PVX-infected, remaining in the ground for a 2 week period following top-kill were significantly (1% level) more susceptible toFusarium tuber rot than those harvested 3 weeks after top-kill; similarly, both PVX-free and PVX-infected tubers harvested 3 weeks after top-kill were significantly (1% level) more susceptible than those left in the ground for a 4–5 week interval.     

Cloning and accumulation of anthocyanin biosynthesis genes in developing tubers

Anthocyanins are a class of flavonoids that are responsible for the pigmentation of red potato periderm. The cDNAs of two genes were cloned from ‘Norland’ periderm and, based on their sequence similarity to genes in various databases, were identified as the anthocyanin biosynthetic genes for leucoanthocyanidin dioxygenase (EC 1.14.11.19) and UDP glucose: flavonoid 3-O-glucosyl transferase (EC 2.4.1.91). The mRNA accumulation of these genes in periderm during the development of tubers was determined using RNA gel blot analyses. The mRNA of the putativeLDOX was detected in cortex tissue and microtubers, but not in periderm. While mRNA of the putativeUFGT was detected in cortex tissue and periderm of young tubers, but not in periderm of tubers weighing more than 25 g. These data suggest that accumulation ofLDOX andUFGT mRNA may limit anthocyanin synthesis as Norland tubers develop.     

Identifying genetic markers of wheat (Triticum aestivum) associated with flavor preference using a laboratory mouse model

Whole wheat products provide critical nutrients for human health, but flavor of whole wheat products may hinder consumer acceptance. However, flavor differences among wheat varieties are not well understood. Using a mouse model system, flavor of whole wheat grain was examined using a two-choice feeding system. A bi-parental recombinant inbred line (RIL) population derived from Clark's Cream x NY6432-18 was used for mapping flavor preference. Clark's Cream is a hard white, and NY6432-18 is a soft white wheat. “Yummy” (cv. Diva soft white) and “yucky” (cv. Macon hard white) varieties were used as ‘checks’ for evaluating each RIL. Marker-trait association was performed using the Student's t as a preference phenotype from each check-RIL comparison. Twenty-two significant marker associations were found. Because mice prefer softer kernel texture, the effect of the Puroindoline b haplotype and phenotypic kernel texture were used as covariates in analyses. Twenty-eight markers exhibited significant associations in the two covariate analyses, with an additional five having significant associations in both covariate analyses. The results indicate that there is an identifiable genetic basis for flavor preference independent of kernel texture. Identifying flavor genes in wheat grain may help facilitate the development of varieties with greater palatability for whole-wheat products.     

Pilot plant for processing flax fiber

A flax fiber pilot plant is needed to process small samples of flax straw into fibers to facilitate research on retting and fiber properties. Our objective was to develop and test a modular design for a flax processing pilot plant based on a commercial line that was capable of cleaning fiber and seed flax straw from unretted, dew-retted, and enzyme-retted samples. The USDA Flax Fiber Pilot Plant (Flax-PP), which is the only research facility of this type in the United States, was designed according to the commercial ‘Unified Line’ (Czech Flax Machinery), but smaller and constructed in four individual modules. The modules and their order for processing were as follows: 9-roller calender, top shaker, scutching wheel, top shaker, 5-roller calender, and top shaker. Illustrations and diagrams of the operating modules are presented. Unretted ‘Neche’ linseed flax, dew-retted ‘Natasja’, and enzyme-retted ‘Jordan’ fiber flax were processed, and the cumulative weight loss of material at successive processing steps was determined to assess the effectiveness of cleaning. Fiber strength, fineness, and elongation were determined for the retted samples after cleaning through all the steps in the Flax-PP. A yield of fine fiber from the retted stems processed through the Flax-PP was acquired from further cleaning and refining by passage through a Shirley Analyzer. The various samples behaved differently at different stages of processing and the resulting fibers had different properties. The dew-retted Natasja fibers were stronger and finer than the enzyme-retted Jordan flax after pilot plant processing, but the Jordan fibers appeared cleaner and better retted. The Flax-PP effectively processed samples of diverse characteristics and will facilitate integrated research on retting methods for fibers with tailored properties.     

番茄不同品种耐酸雨胁迫能力的比较研究

采用‘富丹’、‘倍盈’、‘格林娜’3 个番茄品种为材料，研究不同 pH（3.0、3.5）的模拟酸雨及 pH 5.6（CK）对番茄叶片和花序生长、过氧化物歧化酶（SOD）活性、可溶性蛋白含量、丙二醛（MDA）含量及细胞膜相对透性的影响。结果表明：pH 越低造成的伤害越明显，3 个番茄品种叶片和花序的可见伤害大小依次为‘倍 盈’>‘富丹’>‘格林娜’；在 pH 3.5 及 pH3.0 的酸雨处理后，3 个番茄品种叶片的 SOD 活性相对升高的幅度大小依次为‘格林娜’>‘富丹’>‘倍盈’，可溶性蛋白含量‘格林娜’和‘富丹’>‘倍盈’、下降的相对幅度大小依次为‘倍盈’>‘格林娜’>‘富丹’，MDA 含量水平‘富丹’>‘倍盈’>‘格林娜’，升高的相对幅度大小依次为‘倍盈’>‘富丹’>‘格林娜’，细胞膜相对透性的影响大小依次为‘倍盈’>‘富丹’>‘格林娜’。以上综合说明，‘格林娜’品种耐酸雨胁迫能力最强，‘富丹’品种居中，而‘倍盈’品种最弱。     

抗蚜高产辣椒品种鉴定评价

为了有效满足海南辣椒产业发展需求,系统开展了适于海南种植的抗蚜辣椒品种鉴定与评价.抗蚜性鉴定结果表明,32个参试辣椒品种中,'猪大肠'石柱朝天红'博辣15号'辣丰三号'和'小米椒'5个品种对桃蚜表现为抗蚜,'福康8号'翡翠甜椒'翠玉甜椒'薄冠008'皇帝椒'新香2号'和'干辣3号'7个品种对桃蚜表现为感蚜,'大羊角椒'...     

Impact of sampling and storage technique,and duration of storage,on the composition of fresh grass when analysed using near‐infrared reflectance spectroscopy

The objective of this study was to examine the effect of sampling technique (pluck or cut), storage duration (immediate analysis, 24‐h or 48‐h), storage temperature (ambient or chilled) and storage conditions (air present, air excluded or breathable) on the composition of fresh grass sampled from a sward managed to simulate grazing. Treatments were repeated across four sampling dates, with grass samples stored in grip seal bags prior to analysis using near‐infrared reflectance spectroscopy. Grass sampled by ‘pluck’ had a higher crude protein and ME content, and a lower acid detergent fibre (ADF) content, compared to that sampled by ‘cut’. Grass stored for 48 h had a lower water soluble carbohydrate (WSC) and ME content and a higher ADF content than for immediate analysis. Samples stored for 24 h did not differ from immediate analysis. Grass stored at ambient temperature had a lower WSC and ME content compared to immediate analysis. Grass stored under ‘breathable’ conditions had a lower ME content and higher ADF content than immediate analysis or samples stored with air present or air excluded. It is recommended that grass for analysis should be sampled by cutting, stored chilled (4°C) in a sealed bag to minimize exposure to oxygen and analysed within 24 h of harvest.     

Volatile metabolic profiling for discrimination of potato tubers inoculated with dry and soft rot pathogens

Volatile metabolites from ‘Russet Burbank’ potatoes inoculated withErwinia carotovora ssp.carotovora (ECC),Erwinia carotovora ssp.atroseptica (ECA), andFusarium sambucinum (FSA) were analyzed by sampling the headspace at 3 and 6 days after inoculation and then using a gas chromatograph/mass spectrometer (GC/MS) to identify the compounds. Non-wounded noninoculated and wounded non-inoculated tubers served as checks. Compounds with an abundance of ≥10⁵ and with frequency of ≥3 out of 20 replicates (10 replicates × 2 incubation times) were subjected to further analysis. A total of 81 volatile metabolites were detected, of which 58 were specific to one or common to a few, but not to all inoculations/diseases. Acetic acid ethenyl ester was unique to ECA, while cyclohexene, diazene, and methoxy-(1,1-dimethyl-2-dihydroxy-ethyl)-amine were unique to ECC, and 2,5-norbornadiene and styrene were unique to FSA. Several metabolites were common only to tubers inoculated with ECC and ECA and were not detected in fungus-inoculated or in control tubers. High abundances of acetone and butane were detected in ECC- and ECA-inoculated tubers, respectively. The possible use of differences in volatile metabolic profiles to discriminate diseases of potato tubers in storage is discussed.     

Evaluation of Different Cooking Conditions on Broccoli (Brassica oleracea var. italica) to Improve the Nutritional Value and Consumer Acceptance

The objective of this study was to gain insights into the effect of the cooking method on the liking as well as the retention of glucosinolates in broccoli. With this knowledge it can be concluded whether the health aspects of broccoli be improved by the cooking method without deteriorating sensory perception. For this, broccoli was cooked by methods commonly applied by consumers: boiling with a cold (water) start; boiling with a hot (water) start; and steaming. Firmness, greenness and amount of total glucosinolates in cooked broccoli were instrumentally determined. Sensory evaluation by untrained consumers (n?=?99) for liking and sensory attributes intensity rating were performed on broccoli cooked by steaming and boiling-cold start at three time points, which resulted in ‘high’, ‘medium’, ‘low’ firm broccoli samples. At the end of cooking, steaming showed an increase in the amount of total glucosinolates (+17 %). Boiling-hot start (?41 %) and boiling-cold start (?50 %) showed a decrease in amount of total glucosinolates. Sensory evaluation did not show statistically significant differences between steaming and boiling-cold start in liking at ‘high’ and ‘medium’ firmness; and in the attribute intensity ratings (except for juiciness at ‘medium’ firmness, and flavour at ‘medium’ and ‘low’ firmness). This study demonstrates that medium firm broccoli showed optimum liking and that steaming compared to boiled-cold start showed higher amount of glucosinolates. It is concluded that the health aspects of broccoli can be improved without reducing the sensory aspects by optimising the cooking method.     

不同地理种源金线莲不同采集时间活性成分分析研究

对4个不同地理种源金线莲（‘三明尖叶’、‘三明圆叶’、‘漳州尖叶’及‘台湾AF’）种植满120 d时的生物量及活性成分进行分析比较。结果显示,单株鲜重和干重及多糖含量以‘漳州尖叶’金线莲品种最高,而总多酚及总黄酮含量则均以‘台湾AF’金线莲品种最高。同时对4个金线莲品种不同采集时间的活性成分进行分析比较。结果显示,除‘台湾AF’金线莲品种外,其余3个品种的变化规律大致相同,即随着移栽时间的延长,总多酚及总黄酮含量缓慢增长,而多糖含量则递减。金线莲‘三明尖叶’与‘三明圆叶’品种中,总多酚及总黄酮含量均在种植满150 d达到最大值,此时,在‘三明尖叶’金线莲中,总多酚及总黄酮含量分别为(9.81±0.24)、(4.62±0.16) mg/g;在‘三明圆叶’金线莲中,总多酚及总黄酮含量分别为(9.27±0.22)、(4.60±0.17) mg/g。‘漳州尖叶’金线莲品种的总多酚及总黄酮含量均在种植满120 d达到最大值,分别为(7.74±0.05)、(4.63±0.04) mg/g。‘三明尖叶’、‘三明圆叶’以及‘漳州尖叶’金线莲品种的多糖含量分别于种植满90、0、120 d时达到最大值,多糖含量分别为(26.05±2.11)、(24.29±2.33)、(45.90±4.70) mg/g。此外,对‘三明尖叶’与‘三明圆叶’金线莲品种不同部位活性成分分析发现,多酚与黄酮主要在叶片累积,而糖类物质则主要在茎段累积。