面向草莓抓取的气动四叶片软体抓手研制

农林业中果蔬的自动化采摘需求日趋强烈,末端抓手是实现无损采摘的关键。传统的末端抓手以刚性结构居多,现有的各种柔性抓手也存在抓取力不足、包覆性不佳等缺点。本文以草莓的无损采摘为研究对象,提出将草莓外部轮廓曲线作为设计曲线,设计了一种新型气动四叶片软体抓手。首先,对软体抓手的结构做仿真优化,提出一种安全地附着在目标物表面的设想。然后,在进行草莓表面的最小破坏应力试验的基础上,测试了软体抓手的末端力,验证了其实现无损抓取的可行性。再次,利用动态捕捉技术,研究了软体抓手叶面的弯曲变形规律。最后,选择使用弧线型气体通道的软体抓手进行了草莓抓取测试,结果证明了气动四叶片软体抓手可以实现草莓的无损抓取,抓取成功率达90%,破损率为2%,表明所研制的四叶片软体抓手用于草莓抓取时具有良好的稳定性和实用性,可用于草莓采摘的末端执行器。本研究也可为其他易损果蔬的采摘技术提供理论基础和技术支撑。     

凉州区红颜草莓设施栽培管理技术

从苗木定植、田间管理、环境调控、病虫害防治、果实采收等方面,对凉州区红颜草莓设施栽培技术要点进行介绍,以期设施草莓栽培产业得到更好的发展。     

草莓（Fragaria × ananassa）叶水提物对UVB致 皮肤损伤的保护作用

在草莓叶水提物（Strawberry leaf water extract，SLWE）制备基础上，测定SLWE成分，抗氧化活性、抑制非酶糖基化（NEG）能力，及SLWE对正常生长人皮肤成纤维细胞（HFF-1）细胞活率、透明质酸（HA）、人I型胶原蛋白（COL I）、羟脯氨酸（HYP）、基质金属蛋白酶1（MMP-1）、基质金属蛋白酶9（MMP-9）含量，评价SLWE延缓皮肤衰老功效。在中波紫外线（UVB）致HFF-1损伤模型基础上，测定SLWE对保护组活性氧（ROS）、丙二醛（MDA）、MMP-1和超氧化物歧化酶（SOD）的影响，探讨SLWE对UVB致HFF-1损伤保护机制。结果表明：SLWE富含Vc、槲皮素、绿原酸、没食子酸及儿茶素类物质，其中槲皮素含量12.86 mg/L，表儿茶素含量10.13 mg/L。SLWE自由基清除能力良好，清除不同自由基能力依次为O2-?＞DPPH＞ABTS＞亚铁离子螯和＞?OH；水溶液体积分数为1%的SLWE非酶糖基化抑制率为87.17%；体积分数大于3%的SLWE可提高HFF-1中HA、COL I和HYP含量（p＜0.05），体积分数为6%的SLWE可降低MMP-1含量（p＜0.01），说明SLWE具有提升皮肤含水量，增加胶原含量，抑制胶原降解，实现延缓衰老的功效；在SLWE对UVB致HFF-1损伤保护模型中，SLWE可有效降低因UVB刺激而产生的ROS，体积分数6%的SLWE可显著降MDA，抑制MMP-1表达，提高SOD活力，说明SLWE有助于缓解氧化应激造成的细胞损伤。     

不同贮藏温度对草莓呼吸强度及品质的影响

本文研究了不同贮藏温度(0℃、5℃、10℃、15℃、20℃、25℃、30℃)对草莓呼吸强度、感官评价、失重率、硬度、相对电导率、糖酸比、维生素C和色差的影响。研究表明:贮藏温度越高,草莓呼吸越旺盛,货架寿命越短,草莓30℃条件下的呼吸强度是0℃条件下的13.97倍;草莓在0℃、5℃、10℃、15℃、20℃、25℃、30℃条件下贮藏的商品寿命分别为9 d、7 d、6 d、5 d、3d、2 d、8 h。随着贮藏温度的升高,草莓的失重率、相对电导率和呼吸强度迅速升高,而草莓的感官评价、硬度、糖酸比、维生素C含量、L*、hue值逐渐降低;贮藏在0℃的草莓品质保持最好,贮藏9 d后的感官评价、失重率、硬度、相对电导率、糖酸比、Vc含量、L*和hue值分别为5.4、3.18%、11.13 N、39.05%、12.48、22.01 mg/100 g、37.84、32.81。     

Isolation and identification of high pressure‐resistant bacteria naturally contaminating strawberry pulp

The inactivation of bacteria naturally present in strawberry pulp was investigated after high hydrostatic pressure (HHP) treatment at pressure levels up to 600 MPa at 25 °C for 5 ~ 25 min. Five strains of pressure‐resistant bacteria designated as A, B, C, D and E were isolated and identified. The five strains were gram‐positive, spore‐forming, rods or rod in chains. Growth of the strains was observed at 30 ~ 45 °C, and strain B also grew well at 55 °C. They could produce acid from glucose and were catalase‐positive. Analysis of 16S rRNA gene sequences showed that the five strains belonged to the genus Bacillus. Strain A and D exhibited the greatest 16S rRNA gene sequence similarity of 99% with B. licheniformis and B. firmus, respectively. By combination of phenotypic characteristics and 16S rRNA gene sequences, strain C was B. mycoides and E was B. pumilus. On the basis of physiological and biochemical characteristics, gyrB gene sequences analysis and whole‐cell fatty acids analysis, strain B was B. amyloliquefaciens. Further studies showed that strain B (B. amyloliquefaciens) exhibited the highest pressure resistance, and it was reduced by 4.62‐log after treatment at 600 MPa for 25 min at 25 °C as the most effective observed inactivation.     

草莓保鲜中糖、酸、蛋白质的变化研究

利用蒽酮比色法、酸碱滴定法、考马斯亮蓝法测定草莓保鲜过程中的总糖、总酸、可溶性蛋白质含量的变化。结果表明,低温处理对草莓中糖、蛋白质的保存效果好,对酸的抑制效果也更好。例如：温度低于0℃时草莓保鲜6d后其糖和蛋白质含量仅降低10％左右,酸的含量仅上升11％左右。水分的含量会影响糖、酸、蛋白质的相对含量,并且更低温度有利于水分的保持。     

Antioxidant properties of garden strawberry leaf extract and its effect on fish oil oxidation

The present study characterises garden strawberry leaf extract and reports its effect on shelf life and quality characteristics of fish oil. Radical scavenging capacity of the extract in DPPH^? and ABTS^?+ assays was equivalent to 1207 and 1579 μmol g^?1 of trolox equivalents, respectively, total phenolic content was 257 mg g^?1 of gallic acid equivalents. Phenolic and volatile constituents were analysed by liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS). The extract was added to fish oil and its oxidation was followed during 42 days: peroxide, p‐anisidine values and hexanal concentration were lower in the samples with extract, particularly at the end of storage. The effect of extract on fatty acid composition was not significant, however the changes in the percentages of some individual acids were observed. Fish oil containing 5% of extract had lower levels of lipid oxidation in comparison to other samples. The results indicate that strawberry leaves could be a potential source of natural antioxidants.