新疆库尔勒香梨品质分析与评价

目的 分析比较库尔勒香梨果实品质的区域差异,筛选核心评价指标,探讨果实品质综合评价方法,为库尔勒香梨品质评价提供方法支撑。方法 以新疆库尔勒市、轮台县、阿克苏市等 8 个县市 95 个果园的香梨为试验材料,分别测定可溶性固形物、可滴定酸等 7 项内在品质指标与单果质量、果形指数等 8 项外观品质指标;通过多元统计分析方法筛选核心评价指标并建立综合评价模型,按照先内在品质、后外观品质的逐步评价法评价香梨的品质优劣。结果 香梨各产地间品质离散程度为 3.81%—132.09%;对香梨的内在品质先行评价,通过主成分分析筛选出可溶性固形物、固酸比、硬度三项代表指标累计贡献率达到75.83%,对 95 个果园的香梨进行排名,去除拖尾的 35 个果园的香梨后进行外观评价,筛选出单果质量、b*、果形指数三项外观指标累计贡献率达到79.07%,较全面地表达香梨品质的综合信息,结合聚类分析确定b*、单果质量、固酸比和硬度作为香梨品质评价的重要指标。 结论 基于多元统计分析方法筛选出库尔勒香梨品质的代表指标为b*、单果质量、固酸比和硬度,通过逐级评价方法,筛选出了内在品质和外观品质俱佳的香梨,对95个果园的香梨进行综合评价,发现库车市、轮台县、尉犁县、库尔勒市的果园香梨综合品质表现优秀,沙雅县和阿克苏市的果园品质良好,阿瓦提县和新和县的果园综合品质中等。筛选出的评价指标可综合反映库尔勒香梨的品质内涵,所建立的评价模型可作为香梨品质评价的重要参考。     

QUALITY OF MODIFIED ATMOSPHERE PACKAGED "BARTLETT" PEARS AS INFLUENCED BY TIME AND TYPE OF STORAGE

Commercially mature “Bartlett” pears for this study were obtained from local commercial packing facilities. In the first year, pears were packed in modified atmosphere bags and placed in boxes or packed normally (control) with an individual paper wrap around each pear plus a polyethylene liner in the box. Boxed pears from both types of packaging were stored in regular atmosphere (RA) storage at 1C for 30 or 90 days. In the second year, pears were packed normally and stored in both RA or controlled atmosphere (CA) storage for 45 or 90 days, or packed in modified atmosphere bags and stored in RA at 1C. After 45 days, normally packed pears from both RA and CA were removed from their initial storage, placed in modified atmosphere bags and returned to RA storage for an additional 45 days. Pears stored in modified atmosphere bags were superior in quality to normally packed pears stored only in RA storage and equal in quality to pears stored in CA for periods of 90 days. The quality of pears held in modified atmosphere bags under CA conditions deteriorated after only short periods of time (<45 days). Pears in modified atmosphere bags should be stored only in RA. Little or no quality advantage was evident if use of modified atmosphere bags was delayed regardless of prior storage type.     

FRUIT QUALITY OF "D'ANJOU" PEARS AFTER BIN STORAGE AND LATE-SEASON PACKING

Scald and decay control are problems associated with the long‐term storage of “D’Anjou” pears. In this 3‐year study, D’Anjou pears were treated with combinations of fungicides (Scholar [fludioxinil], Penbotec [pyrimethanil] and Mertect [thiabendazole]), and antiscald agents (ethoxyquin [ETH] and diphenylamine [DPA]). Little decay was evident with or without the use of fungicides, but scald was a major problem after long‐term bin storage. ETH reduced scald incidence, but stimulated the severity of phytotoxicity. However, when fruits were evaluated by quality control personnel, phytotoxicity did not represent a major issue. ETH treatment enhanced sensory scores for finish and pedicel condition, improving fruit grade. In this study, scald control was better with ETH than DPH. However, DPH did produce acceptable scald control even though it aggravated phytotoxicity. D’Anjou pears packed in boxes with ETH and Cu paper wraps developed less decay and scald than pears in polyethylene bags.     

QUALITY OF 'BOSC' PEARS AS INFLUENCED BY ELEVATED CARBON DIOXIDE STORAGE

‘Bosc’pears (Pyrus communis L.) were placed in a purge-type controlled–atmosphere (CA) storage immediately after harvest (>24 h) and held for 180 days at 1C. Oxygen in all atmospheres was 1.5% and CO₂ was 1%, 3% or 5%. Pears were evaluated immediately after removal from CA storage and after ripening for an additional 7 days at 21 C. Pears stored in 3% CO₂ were firmer, had a superior finish, with significantly reduced decay and internal breakdown than pears stored in 1% CO₂. In 3% CO₂, pears retained the ability to ripen after long-term storage. A 10 day delay in atmosphere establishment had little or no influence on the long-term keeping quality or ripening ability of ‘Bosc’pears. Firmness, soluble solids content and starch either alone or together were good indices of maturity for ‘Bosc’ pears.     

The Effect of Gamma Irradiation as a Phytosanitary Treatment on Physicochemical and Sensory Properties of Bartlett Pears

A major concern in exporting agricultural commodities is the introduction or spread of exotic quarantine pests to the new area. To prevent spread of insect pests, various phytosanitary measures are used. Worldwide commercial use of irradiation as a phytosanitary treatment has increased greatly in recent years; however, trade has been limited to tropical fruits. Bartlett pear is a major summer variety of California pears with great potential and market for export. In this study, the effect of gamma irradiation at dose levels of 400, 600, and 800 Gy on physicochemical properties and sensory attributes of early and late harvest Bartlett pears was investigated. Firmness and color changes indicate that irradiation delayed the ripening of pears by 1 d. For the early harvest pears, scarring, bruising, and off flavor were significantly increased at the highest irradiation dose (800 Gy). The appearance of early harvest 800 Gy irradiated pears was the only attribute that received significantly (P ≤ 0.05) lower scores than the control in consumer testing. For the late harvest pears, the 400 Gy fruit had lowest levels of scarring and bruising as rated by trained panelist but consumers did not score the control and 800 Gy fruit differently for any attribute. Titratable acidity, total soluble solids, and chroma were significantly (P ≤ 0.05) decreased and hue increased by irradiation for the early harvest pears. These results suggest that there was a difference in radiotolerance of early and late harvest pears, but in both cases, irradiation at 400 to 600 Gy seemed to maintain best quality.     

Optimization of blended wine quality through maximization of consumer liking

A mixture design was used to optimize blended Vitis vinifera wines (Cabernet Sauvignon, Merlot and Zinfandel) for consumer acceptability. Consumer overall liking values were modeled within an augmented simplex centroid mixture design to determine areas of desirability for each consumer. Two major segments of consumers were identified, with membership mainly dependent upon responses to Zinfandel. Samples were less polarizing when the wines were blended as opposed to remaining as single wines. Three optimized blends were created: for all consumers, segment 1 and segment 2. A subsequent consumer study indicated that optimized blends for each segment were not significantly different from the other wines. However, segment 2 consumers preferred the segment 2 blend to the wine blend optimized across all consumers. The optimized blend across all consumers was the least liked for each segment. Identifying consumer segments can help better optimize products for successful entry into the marketplace. Optimizing a product within a mixture design environment is a useful, efficient technique to understand ingredient interactions and how they affect overall consumer acceptance.     

Comparative sequence analysis of spa gene of Staphylococcus aureus isolated from bovine mastitis: characterization of an unusual spa gene variant

The protein A encoding gene spa of four Staphylococcus aureus strains isolated from bovine clinical mastitis was amplified by PCR and sequenced. The four strains were selected after an initial screening of spa gene of 41 strains isolated from mastitic cows and were subjected to detailed investigations. According to the sequencing results the spa gene of three strains (M1, M2, M3) appeared with gene segments encoding five (E, D, A, B and C) and four (E, A, B and C) IgG binding domains for two (M1, M3) and one (M2) strain, respectively and with gene segments encoding four, two and two repeats of the octapeptide Xr-repeats for the strains M1, M2 and M3, respectively. For the remaining Staph. aureus strain (M4) gene segments encoding IgG binding domains E, D and A and a new domain BC with a size of 219 bp could be observed. The BC domain appears, with a deletion of a 123 bp segment from the border region between both domains, as fused domain of both previously characterized domains. The Xr-region of this strain had 11 octapeptide repeats.     

环锭数码纺纱线特征参数及其对织物外观影响

为明晰基于环锭数码纺纱技术特点所纺数码纺纱线的特征分类,以及对后道织物结构与外观效果的影响,通过分析两通道全二级牵伸数码纺技术原理,纺制一系列变化线密度和混纺比的多类变纱。数码纺纱线的特征参数可定义为：基准线密度、周期长度、混纺比(线密度)变化区间、周期内片段数(或片段变化梯度)。通过对数码纺纱线及其织物分析得到：混纺比(线密度)的变化区间越大,段彩(竹节)效应越强;周期长度决定织物横条的宽度,周期越长,横条越宽;一个周期中包含的片段数量多少对织物段彩(竹节)效应强弱有一定的影响,片段数量增多,段彩(竹节)效应减弱。     

高速贴标机进瓶螺旋的设计与造型

将高速贴标机进瓶螺旋设计为变螺距三段式螺旋,以50000瓶/h的机型为例进行了计算,首先为等速段,然后通过变加速段解决加速度突变带来的冲击,最后为等加速段。给出了利用Matlab绘制的进瓶螺旋运动曲线,提出了用Matlab编程计算螺旋槽上的点,结合SolidWorks实现进瓶螺旋三维造型的方法。     

QUALITY OF ‘GALA’ APPLES AS INFLUENCED BY HARVEST MATURITY,STORAGE ATMOSPHERE AND CONCOMITANT STORAGE WITH ‘BARTLETT’ PEARS1

Controlled atmosphere (CA) storage for 45 or 90 days following harvest reduced quality losses for both ‘Gala’apples and ‘Bartlett’pears compared with fruit from regular atmosphere (RA) storage. Fruit stored in CA were firmer, had higher acidity and less color change than fruit from RA storage. Apples and pears stored together in CA maintained good quality and compared favorably with apples or pears stored separately. There was no difference in fruit quality between fruit stored at 1% O₂ and 1% CO₂ compared with fruit stored in 2% O₂ and 3% CO₂. Fruit harvested at a more advanced stage of maturity deteriorated more quickly in storage than earlier harvested fruit. A combination of 45 days in CA followed by 30 days RA resulted in apples that were superior in quality to apples stored for 75 days in RA alone.     

QUALITY OF PACKED AND BIN STORED 'ANJOU' PEARS AS INFLUENCED BY STORAGE ATMOSPHERE AND TEMPERATURE

Packed pears (Pyrus communis‘d’‘Anjou’) were stored under four individual controlled atmosphere (CA) storage conditions (#1: CA of 1.5% O₂ and < 1% CO₂ at −1.5C; #2: CA of 1.5% O₂ and < 1% CO₂ at + 1.5C; #3: CA of 1.5% O₂ and 3.0% CO₂ at −1.5C; #4: CA of 1.5% O₂ and 3.0% CO₂ at + 1.5C). Loose pears in bins were stored under three CA storage conditions (#1: CA of 1.5% O₂ and <1% CO₂ at −1.5C; #2: CA of 1.5% O₂ and 3.0% CO₂ at −1.5C; #3: CA of 1.5% O₂ and 3.0% CO₂ at +1.5C). For packed pears, increased CO₂ in the storage atmosphere resulted in retention of peel color, reduced firmness loss and enhanced subjective scores, particularly for finish and stem condition. Pears stored loose in bins, prior to packing in late January in an atmosphere containing 3.0% CO₂ aided firmness retention, reduced scald and greatly enhanced subjective quality scores for appearance, finish and scuffing. Storing ‘Anjou’pears in a 3.0% CO₂ atmosphere allows for storing pears loose in bin and packing in late January with little or no quality losses compared with using the standard 1.0% CO₂ in the storage atmosphere.     

Retention of Fortified Vitamin E and Sensory Quality of Fresh-Cut Pears by Vacuum Impregnation With Honey

ABSTRACT:  Our hypothesis was that the incorporation of vitamin E into honey-based vacuum impregnation (VI) solution could be a novel approach to develop high-quality and vitamin E-fortified fresh-cut pears (D'Anjou). A 20% diluted wildflower honey VI solution was used with 0.4% to 0.8%α-tocopherol from 3 different sources: α-tocopherol-acetate (VE-acetate), free α-tocopherol (V-OH), or water-soluble α-tocopherol-acetate (VE-H₂O) for nutritional fortification of the pear slices. Fresh-cut pear slices were immersed in VI solution and subjected to a vacuum at 100 mm Hg for 15 min following atmospheric restoration for 30 min. Samples were stored at 2 °C and 88% relative humidity up to 2 wk for nutritional, physiochemical, and sensory quality evaluations. Vitamin E content of pears impregnated with honey solution containing VE-acetate, VE-OH, or VE- H₂O increased 80 to 100 times and 65% to 80% VE activities were retained during 2 wk storage. Microbial counts were under 2.6 log colony forming unit(CFU)/g pear at the end of 7 d storage, significantly lower than the industrial standard. Instrumental color analysis and sensory evaluation indicated that VE fortified pear slices had significantly higher lightness, lower browning index, and higher consumer acceptance rating than control (unfortified) ones. There is a strong Pearson correlation between instrumental analysis and consumer sensory evaluation in pear color. This study demonstrated a great potential for developing high-quality, vitamin E-fortified fresh-cut pears by use of VI technology with honey, thus further enhancing the health benefit of pears.     

Limitations to modified atmosphere packaging for extending the shelf-life of partly ripened Doyenné du Comice pears

Although some retardation in ripening of Doyenne du Comice pears can be obtained when unripe fruit are held in modified atmosphere packs (MA) at 20°C, softening proceeds at a faster rate than chlorophyll loss so that the appearance of the fruit fails to match its internal condition. However, a 4-day extension in shelf-life was obtained by packing the fruit in a part-ripe condition and, although the effects on rate of softening were less than those seen for unripe fruit, the yellower ground colour was more consistent with the eating qualities of the fruit. Increases in fruit-to-fruit variability, and in the risk of skin injury as the pears ripen in MA packs which were also recorded, are likely to preclude the commercial adoption of this technique for Comice pears.     

Extending Shelf Life of Fresh-cut Pears

The effects of various treatments were evaluated for extending shelf-life of fresh-sliced pears. Sliced Anjou pears had browning-free color for 30 d by dipping with 1.0% ascorbic acid and 1.0% calcium lactate, but texture was soft with juice leakage. The combination treatment of 0.01% 4-hexylresorcinol (4-HR), 0.5% ascorbic acid and 1.0% calcium lactate can provide 15 to 30 d shelf-life for Anjou, Bartlett, and Bosc pears when the pears are sliced at an average ripeness of 43, 49, and 38 Newton respectively, with 2 min dipping, partial vacuum packaging, and 2 to 5 °C storage. 4-HR residual content ranged from 1 to 7 ppm after 14 d storage. Panelists could detect a flavor difference between 0.01% 4-HR treated pears and controls.     

硬段含量对水基聚氨酯性能的影响

以聚四氢呋喃醚二元醇(PTMG)作为软段、以异氟尔酮二异氰酸酯(IPDI)、1,4-丁二醇(1,4-BDO)作为硬段、以2,2-二羟甲基丙酸(DMPA)为亲水扩链剂,合成一系列硬段含量不同的水性聚氨酯,并研究了硬段含量对合成革用水性聚氨酯性能的影响。结果显示:在R(—NCO/—OH)值,DMPA含量不变的情况下,硬段含量在40%时,聚氨酯膜的拉伸强度、断裂伸长率、吸水率、玻璃化转变温度等综合性能优良,适合合成革的制造。     

Irish consumer acceptance of a hypothetical second-generation GM yogurt product

This paper examines Irish consumer acceptance of second-generation GM products, defined here as those which are expected to exhibit a specific consumer-oriented benefit. Conjoint analysis was used to determine Irish consumer preferences (n = 297) for attributes of a hypothetical GM yogurt. Cluster analysis on the basis of the GM attribute revealed four segments of consumers. An “anti-GM” segment (24.4% of sample) were outright rejecters of all GM foods, while a second cluster (33.4%) specifically rejected second-generation GM products. A further 20.5% of the sample were receptive to the notion of second-generation GM products. However, this group had a number of complex reservations, which would need to be resolved before they would truly accept such products. GM foods offering specific consumer benefits were found to be acceptable to 21.2% of the sample, implying that these foods could represent a segment within the overall food market in the future.     

Residual gas and storage conditions affect sensory quality of diced pears in flexible retortable pouches

Diced pears packed in flexible retortable pouches were manufactured to obtain packages with 10, 15, 20 and 30 cm³ residual gas, then stored at 4.4, 26.7 and 37.8 °C for six months. The 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde values increased and pears turned darker, softer, more homogeneous in shape/size, less fruity in flavor and aroma, and less acceptable to consumers over time. Elevated temperatures and high residual gas levels were particularly detrimental to pear quality. Highest quality was maintained for 6 months when pears packaged at any residual gas level were stored at 4.4 °C. Acceptable quality was maintained for 6 months in pears packaged with less than 30 cm³ residual gas, stored at 26.7 °C. Pear quality declined most rapidly at 37.8 °C, 30 cm³ residual gas. Residual gas volume of 15 cm³ should not be exceeded to maintain highest quality and acceptability of diced pears packed in flexible retortable pouches.     

鲜切梨褐变抑制的研究

研究了不同褐变抑制剂对鲜切梨褐变度、PPO活性、感官品质的影响.实验结果表明,单一使用1.0%柠檬酸、0.01%水杨酸、0.3% L-半胱氨酸处理均能较好的抑制鲜切梨褐变.但是采用0.3%L一半胱氨酸+0.01%水杨酸+1.2%柠檬酸,浸泡9min的复合处理效果最佳,可使鲜切梨的褐变度在12d内保持较优水平.     

切段对韭菜贮藏品质及抗氧化活性的影响

为了明确家庭存贮条件下鲜切韭菜段的营养性和食用期,本文研究了切段对韭菜贮藏品质和抗氧化活性的影响。将新鲜791韭菜切割成3~4 cm小段后置于温度28±1℃,相对湿度50%±5%环境下（模拟家庭贮藏条件）贮藏4 d。结果表明:切段导致了韭菜辛香味即刻增强,随后辛香味逐渐变淡,整个贮藏期韭菜段和完整韭菜风味雷达图的外型和轮廓相似,但是面积不同。韭菜段常温贮藏第3 d感官品质评分低于5分,主要营养成分维生素C（V_C）损失严重,叶绿素含量下降明显;3 d内,抗氧化物质总酚和类黄酮含量增加,过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性增强。综上,建议家庭贮藏环境下,鲜切韭菜段最佳食用期为0~1 d,最佳货架期为0~2 d。