Acetylsalicylic acid alleviates chilling injury of postharvest loquat (Eriobotrya japonica Lindl.) fruit

Loquat (Eriobotrya japonica Lindl. cv. Luoyangqing) is a chilling-sensitive fruit and therefore has a limited postharvest life. While fruit stored at 5 °C retained its acceptable quality after 39 days, fruit stored at 0 °C had chilling injury with the symptoms of tissue browning and lignification, decrease in percentage juice, increase in superoxide free radical production, electric conductivity and lignification enzyme activities, including phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and guaiacol-peroxidase (G-POD). Such chilling injury symptoms became more severe after fruit were moved to 20 °C shelf life. A postharvest application of 1 mmol/L aqueous acetylsalicylic acid (ASA, a derivative of salicylic acid) to loquat fruit significantly alleviated chilling injury symptoms, inhibited accumulation of superoxide free radical, and reduced PAL, CAD, and G-POD activities. ASA treatment impairing the accumulation of superoxide free radical may prevent chilling injury and lignification in loquat.     

Cold-induced ethylene in relation to chilling injury and chilling sensitivity in the non-climacteric fruit of zucchini (Cucurbita pepo L.)

Zucchini is a non-climacteric fruit which is harvested immature on reaching about 18 cm in length. In the present paper we compare fruit quality parameters in different zucchini cultivars with the production of ethylene and the expression of two ethylene biosynthesis genes (CpACS1 and CpACO1) throughout postharvest storage at 4, 12 and 20 °C. In fruit stored at 12 or 20° ethylene production and expression of CpACS1 and CpACO1 genes remained very low throughout the whole storage period. Ethylene production was also low at 4 °C, but was induced rapidly upon transfer to 20 °C for a minimum of 4 h. The expression of both CpACS1 and CpACO1 genes was also induced by storage at 4 °C. This cold-induced ethylene is not necessary for triggering chilling injury (CI) symptoms in zucchini, since they were already evident in the cold chambers before rewarming of the fruit and, therefore, before the burst of ethylene. However, the level of the cold-induced ethylene was lower in those cultivars that were more tolerant to CI, and it fell in response to temperature conditioning treatments that alleviate CI symptoms.     

Alleviation of chilling injury and browning of postharvest bamboo shoot by salicylic acid treatment

The effects of salicylic acid (SA) treatment on chilling injury, disease incidence, electrolyte leakage (EL), flesh browning index, malondialdehyde (MDA) and total phenolic content, phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) activities, and polyamine (PA) content of bamboo shoot, during storage at 1 °C for 50 days, were examined. Chilling injury and disease incidence, EL, MDA content of control shoot increased progressively. Chilling injury promoted PAL, PPO and POD activities, which are associated with shoot total phenolic content and flesh browning index increase. Chilling injury was significantly positively correlated with putrescine (Put) or spermidine (Spd) contents. Suppression of chilling injury by SA treatment was associated with reducing EL, MDA and total phenolic content, retarding activities of PAL, PPO and POD, and promoting PA accumulation. The present findings suggest that SA treatment could be used commercially to control chilling injury in bamboo shoot during cold storage.     

Fatty acid composition and antioxidant system in relation to susceptibility of loquat fruit to chilling injury

Two cultivars of loquat fruit with contrasting chilling resistance were stored at 1 °C for 35 days to investigate the relationship between chilling injury and fatty acid composition and its antioxidant system. No symptoms of chilling injury occurred in the fruit of ‘Qingzhong’ cultivar during the whole storage, whereas in ‘Fuyang’ fruit, chilling injury increased sharply after 21 days of storage at 1 °C. ‘Qingzhong’ fruit had lower levels of superoxide radical and H₂O₂, in addition to lower lipoxygenase activity, but higher membrane lipid unsaturation and higher activities of superoxide dismutase and catalase than ‘Fuyang’. Furthermore, the chilling resistant ‘Qingzhong’ fruit also showed higher activities of antioxidant enzymes involved in ascorbate–glutathione cycle and higher levels of ascorbate acid and reduced glutathione. These results suggest that the higher membrane lipid unsaturation and the more efficient antioxidant system were both beneficial in enhancing resistance of loquat fruit to chilling injury.     

Effect of methyl jasmonate on cell wall modification of loquat fruit in relation to chilling injury after harvest

Loquat fruit were pretreated with 10 μM methyl jasmonate (MeJA) for 24 h at 20 °C, and then stored at 1 °C for 35 days to investigate the effect of MeJA treatment on cell wall modification in relation to chilling injury. Loquat fruit developed chilling injury, manifested as increased fruit firmness and internal browning, decreased extractable juice during storage. These chilling injury symptoms were significantly reduced by MeJA treatment. MeJA also markedly delayed the increases in lignin, alcohol insoluble residues, hemicellulose and cellulose. Meanwhile, the MeJA-treated fruit exhibited significantly lower activities of phenylalanine ammonia lyase, peroxidase, polyphenol oxidase and higher polygalacturonase activity than the control during storage. The levels of water- and CDTA-soluble pectins in MeJA-treated fruit were also significantly higher than that in the control. These results suggest that the reduction in chilling injury by MeJA may be due to inhibited lignin accumulation and enhanced cell wall polysaccharides solubilisation.     

An Approach for Monitoring the Moisture Content Changes of Drying Banana Slices with Laser Light Backscattering Imaging

Moisture content is an important quality attribute that directly influences storability of fruits and vegetables. The main goal of the present work was to test laser light backscattering imaging technique as a monitoring tool during drying of banana (Musa × cavendishii L.) slices. Laser diode emitting at 670 nm was used as the light source, whereas a charge-coupled device camera served as detector. The photon migration into the tissue was recorded as the average profile of the intensity gradient and expressed by two parameters, the size of the total illuminated area (square centimeters) on the surface and the radius (centimeters) of this area. The two attributes correlated with each other (r = 0.97–0.98). Backscattering images of slices were acquired each hour during the drying process at three different temperatures: 53, 58, and 63 °C. The two parameters of the intensity profile responded sensitively to changing moisture content. Significant relationship was found between changes in backscattering area and moisture content, especially at lower temperatures (r = 0.76, T = 53 °C), when almost no tissue browning occurred. At higher temperatures, correlations were observed between the parameters extracted by image processing and a* standard color index, especially at increased drying temperature due to the browning of the tissue.     

质构仪在果实品质测定方面的研究与应用

因其测定结果的高度灵敏性和客观性,质构仪越来越频繁的应用到食品的物性研究及检测当中。目前在果蔬测定中只局限于单一的质构参数的测定与研究,通过对质构仪在当前水果方面应用概况的了解及分析,提出了质构仪测定方法今后在果蔬测定方面的应用,并对其今后的发展方向进行了预测和展望。     

Alleviation of chilling injury in postharvest tomato fruit by preconditioning with ultraviolet irradiation

BACKGROUND: Tomato fruit is usually stored at low temperatures for delayed ripening and extended shelf life. However, tomato fruit is susceptible to chilling injury when exposed to low temperatures. In this study, the potential effects of preconditioning with UV‐C or UV‐B irradiation on chilling injury of postharvest tomato fruit were investigated. RESULTS: Mature–green tomato fruit were exposed to 4 kJ m^?2 UV‐C or 20 kJ m^?2 UV‐B irradiation and stored for 20 days at 2 °C and subsequently 10 days at 20 °C. UV irradiation was effective in reducing chilling injury index and delaying ethylene peak. Furthermore, UV irradiation preserved storage quality as manifested by reduced weight loss, better retention of firmness, and higher contents of total soluble solids, soluble protein and soluble sugar during subsequent storage at 20 °C. UV‐C irradiation significantly delayed the development of the red colour after 10 days of storage at 20 °C. On the other hand, UV irradiation decreased total phenolics content and antioxidant capacity, suggesting possibly reduced stress response to low temperature resulted from enhanced physiological adaptation by UV preconditioning. CONCLUSION: Our results suggest that preconditioning with UV‐C or UV‐B irradiation in appropriate doses had a positive effect on alleviating chilling injury in postharvest tomato fruit. Copyright © 2012 Society of Chemical Industry     

Effects of type of packaging material on shelf-life of fresh broccoli by means of changes in weight,colour and texture

Five polymeric films were studied to determine their ability to retain the colour, weight and texture of broccoli (Brassica oleracea L. var. Italica Monterey). The materials were oriented polypropylene (OPP), polyvinyl chloride (PVC) and two different low-density polyethylenes (LDPE), one of which contained a sachet reported to absorb ethylene. The broccoli was packaged and stored at 4 and 10 °C for 4 weeks. The weight, colour, chlorophyll content and texture were monitored during storage as well as O₂ and CO₂ concentrations inside the packages. Packaging prolonged the broccoli shelf-life by up to 14 days. The shelf-life varied depending on the packaging material and quality parameter considered. The atmosphere was modified inside the packages; however, no package provided the recommended atmosphere (O₂ 1–2% and CO₂ 5–10%) for broccoli. Packaging in OPP resulted in the highest CO₂ concentration, 6%, while the lowest O₂ concentration, 9%, was created in the LDPE package without a sachet for ethylene absorption. Storage in LDPE without ethylene absorber resulted in the overall longest shelf-life. Broccoli stored in PVC deteriorated faster than broccoli packaged in the other materials. The influence of packaging material was greater at the higher temperature.     

青椒果实冷害与活性氧清除酶和脂氧合酶活性变化的关系

青椒在9℃下冷藏8周,未出现冷害,膜透性变化不大。而在2℃下贮藏1周后即出现冷害症状,超过4周发生严重冷害,膜透性迅速上升。与9℃贮藏青椒相比,2℃贮藏的青椒SOD活性降低,而CAT和APX活性降低更多;POD活性也明显低于9℃贮藏青椒,但7周时骤升至峰值。9℃下青椒的LOX活性变化很小,而2℃下青椒的LOX活性2周时迅速上升,此后保持较高的水平。低温促进了膜脂过氧化产物MDA的积累,使2℃下青椒的MDA含量高于9℃的。可见青椒的冷害与低温下活性氧清除酶,特别是CAT和APX活性的降低以及LOX活性增强,导致活性氧化代谢失调和膜脂过氧化有关。     

An alternative method for the industrial monitoring of osmotic solution during dehydration of fruit and vegetables: A test-case for tomatoes

In this paper, an alternative procedure for in situ and continuous monitoring of the status of the hypertonic solutions used in industrial osmotic dehydration (OD) process of fruit and vegetables is presented and validated. The proposed method, which is based on microwave reflectometry technique, circumvents the limitation of traditional control methods, since it discovers the relation between the characteristic parameters of osmotic solutions and the corresponding measured reflection coefficients. In fact, as the OD proceeds, the dielectric characteristics of the solution, associated to the reflectometry measurements, can be directly related to the variation of the water activity (a_w), which is the parameter that is typically considered to assess the dewatering capacity of the solution. As a result, through the method presented herein, a continuous monitoring of the dewatering capacity of the osmotic solution, associated to its qualitative status, is possible, which, in turn, is useful also for optimizing the OD industrial process. The proposed method was preliminarily validated on reference aqueous solutions of sucrose. Successively, the method was tested also in a typical industrial application, involving the OD process of tomatoes.     

Use of a portable hyperspectral imaging system for monitoring the efficacy of sanitation procedures in produce processing plants

Cleaning and sanitation of production surfaces and equipment plays a critical role in lowering the risk of food borne illness associated with consumption of fresh-cut produce. Visual observation and sampling methods including ATP tests and cell culturing are commonly used to monitor the effectiveness of the cleaning procedures. This study tested the ability of a hand-held VIS hyperspectral imaging system to augment current monitoring methods. Multiple visits were made to two commercial fresh-cut processing facilities. Fluorescence-based detection and automated cycling among three wavelengths, 475, 520, and 675 nm, proved best for detecting a range of anomalies. Numerous deficiencies in existing cleaning protocols were identified. Plant personnel were able to devise changes in the protocols that eliminated most of the detected problems without increasing the net expenditure for cleaning efforts. In addition, imaging identified sites where ATP test results were higher when compared to results for adjacent areas.     

Development of a portable hyperspectral imaging system for monitoring the efficacy of sanitation procedures in food processing facilities

Cleaning and sanitation in food processing facilities is a critical step in reducing the risk of transfer of pathogenic organisms to food consumed by the public. Current methods to check the effectiveness of sanitation procedures rely on visual observation and sub-sampling tests such as ATP bioluminescence assays and culturing methods. To augment existing verification methods, a hand-held visible hyperspectral imaging device was developed. The device is capable of acquiring reflectance images using ambient lighting, and fluorescence responses to supplemental violet (405 nm) excitation. To enhance the ability of detecting relatively low intensity fluorescence responses in the presence of ambient lighting, the device includes the ability to identify wavebands where the intensity of ambient lighting is relatively low. Valleys in ambient illumination intensity when using fluorescent lighting were found at around 475, 520, 570, and 675 nm. A principal goal is to acquire data to support development of a commercially-viable, hand-held, imaging system.     

利用DA7200近红外仪快速检测大豆粕品质的研究

本研究利用瑞典波通DA7200型固定光栅连续光谱近红外分析仪对460份来自阿根廷、美国和巴西三个国家的进口大豆加工的豆粕进行了分析,并根据定标样品的吸收光谱与化学分析数据建立了豆粕的水分．蛋白质及脂肪等三项指标的定标模型。定标模型的统计分析结果显示,三项指标的模型均具有较高的相关性（R^2=0．9616-0．9886）．和较低的交互验证标准偏差（SECV=0．0794～0．2160）。选用具有代表性的预测集样品对校准模型的准确性进行预测。预测结果显示：预测标准偏差在0．10～0．27之间,双试样标准差在0．03～0．10之间。近红外光谱技术用于快速测试豆粕品质是可行的,能够用于豆粕生产厂家产品的品质控制。     

A combination of near-infrared hyperspectral imaging with two-dimensional correlation analysis for monitoring the content of biogenic amines in mutton

The study investigated the feasibility of using a combination of near-infrared hyperspectral imaging (NIR-HSI) with two-dimensional correlation (2DCOS) analysis for rapid and non-destructive determination of the content of biogenic amines in mutton during refrigerated storage. Total contents of biogenic amines (TBA) were used as the perturbation. By analysing the synchronous and asynchronous two-dimensional correlation spectra, sensitive variables that were closely related to TBA contents were obtained. The results showed that the wavelengths in the spectra range of 1002–1335 nm were the research area for the detection of TBA contents in mutton. The least-squares support vector machines (LSSVM) model based on effective wavelengths selected by competitive adaptive reweighted sampling (CARS) from 2DCOS analysis showed excellent results, with correlation coefficient in prediction (Rp) of 0.91, root mean square error in prediction (RMSEP) of 1.67 mg kg⁻¹ and the ratio of performance deviation (RPD) of 2.76. The research demonstrated that the combination of NIR-HSI and 2DCOS could be used as an effective method for monitoring the content of biogenic amines in mutton.     

梓葛冻干粉针对脑缺血/再灌注损伤大鼠脑微血管通透性的影响及其机制研究

本文探讨梓葛冻干粉针对脑缺血/再灌注损伤大鼠脑微血管通透性的影响及其作用机制。选择雄性SD大鼠320只,随机分为假手术组、模型组、葛根素注射液组、尼莫地平组和梓葛冻干粉针3个剂量组。线栓法复制大鼠缺血再灌注模型,分别缺血2 h,于再灌注1、4、7和14 d给药后,取脑提取微血管,分别用Western blot法测定脑微血管中闭合蛋白（Occludin）、紧密连接蛋白-5（Claudin-5）、闭合小带蛋白-1（ZO-1）、基质金属蛋白酶-9（MMP-9）的蛋白表达。结果表明,与模型组相比,再灌注4、7和14 d,梓葛冻干粉针16.40、32.70和65.40 mg·kg-1能抑制脑缺血/再灌注大鼠缺血侧脑皮质层微血管中MMP-9蛋白表达的升高;并促进微血管中Claudin-5、Occludin、ZO-1蛋白表达。说明梓葛冻干粉针影响脑缺血/再灌注损伤大鼠脑微血管通透性的机制可能是通过抑制MMP-9蛋白表达,并促进Claudin-5、Occludin、ZO-1蛋白表达,进而保护和改善脑微血管通透性。      

An international quality assurance scheme for the quantitation of daidzein and genistein in food,urine and plasma

This quality assurance (proficiency testing) scheme was commissioned to enable the Food Standards Agency (FSA) to determine the quality of analytical results submitted by researchers measuring the concentrations of phytoestrogens in foods and biological fluids in FSA-funded research projects, and also, to demonstrate that FSA-funded laboratories are producing consistent and precise results. Non-FSA-funded laboratories from around the world were also invited to join in the scheme to increase the number participants. A secondary objective was to highlight the most successful methodologies used to analyse phytoestrogens.