Effects of Different Storage Temperatures on Shelf Life and Quality of Strawberry Fruit after Hot Water Treatment

Taking the strawberry fruit from an agro-ecological park in Cangzhou as the experimental material,the effects of different storage temperatures on the shelf life and quality of strawberry fruit were studied.After being treated with hot water at 42℃,the strawberry fruit was stored at(20-25)℃and(4±1)℃,respectively.It was found that the weight loss,cell membrane permeability,titratable acid content and soluble solids content differed between different storage temperatures.At low temperature,the quality of the strawberry fruit was better,and their decay was delayed by 12 d,that is,their shelf life was extended from 2 to 14 d.After hot water treatment,the permeability of the cell membrane and the contents of titratable acid and soluble solids in the strawberry fruit increased.In summary,low temperature can better maintain the quality of strawberry fruit.

Research Progress in the Extraction and Application of Flavonoids from Ginkgo biloba Leaves

Ginkgo biloba resources in China are enormous. With the demand of the market, the preparation and application of flavonoids have become a current research hotspot. The main active substances in G. biloba leaves, flavonoids, have various functional activities and are widely used in fields such as food, medicine, cosmetics, feed, etc. In this paper, the introduction, functional activity, extraction methods, and application research of flavonoids from G. biloba leaves are reviewed, and the development prospects of flavonoids from G. biloba leaves are expected.

Research Progress of Cellulase

Cellulase is a complex enzyme that can decompose cellulose into glucose,and it could effectively treat cellulose waste. In this paper,it aims to explore development status and research progress of cellulase,and introduce concept and action mechanism of cellulase,research situation of cellulase in molecular aspect,application of cellulase,and development of cellulase is also prospected.

Coping with extremes:lowered myocardial phosphofructokinase activities and glucose content but increased fatty acids content in highland Eurasian Tree Sparrows

Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate utilization of highland animals varies with evolutionary history and phylogeny.The heart is a proxy for the cardiopulmonary system,and the metabolic substrate utilization in the myocardium is also under the strong selective pressure of chronically hypoxic and hypothermic environments.However,little information is available on the physiological adjustments in relation to metabolic substrate utilization in the myocardium for coping with high-altitude environments.Methods:We compared the metabolic enzyme activities,including hexokinase(HK),phosphofructokinase(PFK),pyruvate kinase(PK),citrate synthase(CS),carnitine palmitoyl transferase 1(CPT-1),lactic dehydrogenase(LDH),and creatine kinase(CK),and metabolic substrate contents including glucose(Glu),triglyceride(TG),and free fatty acid(FFA)in the myocardium of a typical human commensal species,Eurasian Tree Sparrows(Passer montanus)between the Qinghai-Tibet Plateau(the QTP,3230 m)and low altitude population(Shijiazhuang,80 m),and between sexes.Results:Among the seven metabolic enzymes and three substrates investigated,we identified no significant differences in PK,CPT-1,HK,CS,LDH,and CK activities and TG content of the myocardium between high and low altitude populations.However,the QTP sparrows had significantly lower Glu content and PFK activities but higher FFA content relative to their lowland counterparts.In addition,male sparrows had higher myocardial HK and CS activities relative to females,independent of altitude.Conclusions:Our results showed that the QTP sparrows elevated fatty acid utilization rather than glucose preference in the myocardium relative to lowland counterpart,which contributes to uncovering both the physiological adjustments for adapting to the extreme conditions of the QTP,intraspecifically.

Research Status of Medicinal Plant Purslane

The research status of nutrient composition, medicinal value, development and utilization and cultivation techniques of purslane was analyzed to provide reference for further development and utilization of medicinal plant purslane.

Effect of Different Processing Methods on Storage Quality of Strawberries

[Objectives]This study aimed to explore the effect of different processing methods on the storage quality of strawberries.[Methods]Strawberries purchased from Xintongtian Supermarket in Cangzhou City were used as the experimental material,and they were subjected to different processing methods:45℃hot air for 30 min,45℃hot water for 10 min and 3%calcium chloride for 1 min.[Results]The processing effect of 45℃hot water for 10 min was better than that of 45℃hot air for 30 min.The processing effect of 3%calcium chloride for 1 min was good.Hot water processing could prolong the time to begin to rot,obviously alleviate the increase in weight loss rate,and obviously alleviate the decrease of soluble solids and Vc contents of strawberry fruit.However,the ability of hot water to delay the decrease of strawberry fruit hardness was not as good as that of calcium chloride.[Conclusions]The strawberries processed with 45℃hot water for 10 min showed the best storage quality.

Effects of Different Storage Conditions on Physiological and Biochemical Characteristics of Polygala tenuifolia Willd. Seeds

[Objectives] Taking Polygala tenuifolia Willd. seeds as experimental material, the changes of physiological and biochemical characteristics of seeds under different storage temperatures and seed moisture contents were studied. [Methods] The seeds of P. tenuifolia Willd. with moisture contents of 3%, 5% and 15% were stored at-10 ℃, 0 ℃, 20 ℃ and 36 ℃, respectively, and the storage time was one year. The physiological and biochemical characteristics of the seeds, such as conductivity, SOD activity, POD activity, and soluble sugar content were studied.[Results] After one-year storage, as the storage temperature and seed moisture content increased, the relative conductivity, MDA content and soluble sugar content of P. tenuifolia Willd. seeds increased, while the SOD activity, POD activity, and protein content declined. This phenomenon was most obvious in the P. tenuifolia Willd. seeds with moisture content of 15%. [Conclusions] This study will provide reference for seed storage of medicinal plants.

Content Determination of Trace Elements in Several Vegetables by Atomic Absorption Spectrophotometry

The contents of Mn,Zn and Cu,three essential trace elements for human body,in Laminaria japonica,Auricularia auricula( L. ex Hook.) Underwood,Porphyra,Cucurbita pepo L.,Spinacia oleracea L. and Coriandrum sativum were determined by atomic absorption spectrophotometry. Vegetable samples were processed by wet digestion. The results showed that among the six vegetables,Mn had the highest content in A. auricula( 26. 60 μg/g) and the lowest content in C. pepo( 1. 22 μg/g); Zn had the highest content in Porphyra( 38. 07 μg/g)and the lowest content in L. japonica( 10. 32 μg/g); and Cu had the highest content in Porphyra( 10. 35 μg/g) and the lowest content in S. oleracea( 0. 61 μg/g). Each determination was repeated five times. The value of RSD was less than 10%,indicating high accuracy.

Comparison of Polysaccharides Content among Common Fruits

[Objectives]Polysaccharides in common fruits were determined and compared.[Methods]Polysaccharides in fresh bananas,apples,grapes and strawberries purchased from local markets were extracted using water extraction-alcohol precipitation method and determined using 3,5-dinitrosalicylic acid(DNS)method.[Results]The content of polysaccharides in banana was relatively high.The optimal conditions for DNS colorimetry were as follows:measurement wavelength of 510 nm,color developer of 1.0 mL,color development temperature of 90℃,color development time of 5min and stabilization time within 30 min.[Conclusions]The reproducibility and recovery rate of this method are ideal.It shows that the method is highly precise and is helpful for the research of fruit polysaccharides.This study provides a certain reference value for the development and application research of fruit polysaccharide resources in China.

Functional evaluation of the insulin/insulin-like growth factor signaling pathway in determination of wing polyphenism in pea aphid

Wing polyphenism is a common phenomenon that plays key roles in environmental adaptation of insects.Insulin/insulin-like growth factor signaling(IIS)pathway is a highly conserved pathway in regulation of metabolism,development,and growth in metazoans.It has been reported that IS is required for switching of wing morph in brown planthopper via regulating the development of the wing pad.However,it remains elusive whether and how IIS pathway regulates transgenerational wing dimorphism in aphid.In this study,we found that pairing and solitary treatments can induce pea aphids to produce high and low percentage winged offspring,respectively.The expression level of ILP5(insulin-like peptide 5)in maternal head was significantly higher upon solitary treatment in comparison with pairing,while silencing of ILP5 caused no obvious change in the winged offspring ratio.RNA interference-mediated knockdown of FoxO(Forkhead transcription factor subgroup O)in stage 20 embryos significantly increased the winged offspring ratio.The results of pharmacological and quantitative polymerase chain reaction experiments showed that the embryonic insulin receptors may not be involved in wing polyphenism.Additionally,ILP4 and ILP11 exhibited higher expression levels in 1st wingless offspring than in winged offspring.We demonstrate that FoxO negatively regulates the wing morph development in embryos.ILPs may regulate aphid wing polyphenism in a developmental stage-specific manner.However,the regulation may be not mediated by the canonical IIS pathway.The findings advance our understanding of IIS pathway in insect transgenerational wing polyphenism.

Characteristics of soil nutrients and their relationship with soil microbial properties in Artemisia sacrorum communities in the loess hilly region

Artemisia sacrorum communities with different growth years were selected to analyse soil nutrient characteristics,the variation in soil microbial properties,and their relationships in the loess hilly region.The results showed that with an increase in the number of growth years,soil microbial biomass carbon and nitrogen contents as well as soil phosphatase and urease activities initially decreased and then increased in the A.sacrorum communities.The soil organic carbon,organic nitrogen,and total nitrogen contents as well as soil respiration rate showed an increasing trend and reached a maximum at age(a)37.The soil available phosphorus content first decreased and then increased,with the lowest level observed at 18 a.By contrast,soil available potassium initially increased and then decreased.Soil microbial biomass carbon had a significant positive correlation with soil organic carbon,total nitrogen and organic nitrogen,while soil respiration had a significant positive correlation with organic nitrogen,soil phosphatase and organic carbon.Soil respiration had a highly significant positive correlation with organic carbon and total nitrogen,while soil phosphatase had a highly significant positive correlation with total nitrogen and organic nitrogen.In the A.sacrorum communities,the soil organic carbon and total nitrogen contents were mainly affected by soil respiration,soil available potassium content was mainly affected by soil urease activity,and soil organic nitrogen content was mainly affected by soil phosphatase activity.These findings indicate that soil basal respiration,urease activity and phosphatase activity were the major microbial factors affecting the characteristics of the soil nutrients in the A.sacrorum communities.In conclusion,the natural restoration process of A.sacrorum communities can enhance soil microbial activity and improve soil quality.

Functional characterization of a novel, highly expressed ion-driven sugar antiporter in the thoracic muscles of Helicoverpa armigera

Sugar transporters(STs),which mainly mediate cellular sugar exchanges,play critical physiological roles in living organisms,and they may be responsible for sugar exchanges among various insect tissues.However,the molecular and physiological functions of insect STs are largely unknown.Here,16 STs of Helicoverpa armigera were identified.A phylogenetic analysis classified the putative HaSTs into 12 sub-families,and those identified in this study were distributed into 6 sub-families.Real-time polymerase chain reaction indicated that the 16 HaSTs had diverse tissue-specific expression levels.One transporter,HaST10,was highly expressed in thoracic muscles.A functional study using a Xenopus oocyte expression system revealed that HaST10 mediated both H+-driven trehalose and Na+-driven glucose antiport activities with high transport efficiency and low affinity levels.A HaST10 knockout clearly impaired the performance of H.armigera.Thus,HaST10 may participate in sugar-supply regulation and have essential physiological roles in H.armigera.

Quantitative Assessment of the Ecological Vulnerability of Baiyangdian Wetlands in the North China Plain

Quantitative assessment of vulnerability is a core aspect of wetland vulnerability research.Taking Baiyangdian(BYD)wetlands in the North China Plain as a study area and using the‘cause-result’model,23 representative indicators from natural,social,sci-tech and economic elements were selected to construct an indicator system.A weight matrix was obtained by using the entropy weight method to calculate the weight value for each indicator.Based on the membership function in the fuzzy evaluation model,the membership degrees were determined to form a fuzzy relation matrix.Finally,the ecological vulnerability was quantitatively assessed based on the comprehensive evaluation index calculated by using a composite operator to combine the entropy weight matrix with the fuzzy relation matrix.The results showed that the ecological vulnerability levels of the BYD wetlands were comprehensively evaluated as Grade Ⅱ,Grade Ⅲ,Grade Ⅳ,and Grade Ⅲ in 2010,2011-2013,2014,and 2015-2017,respectively.The ecological vulnerability of the BYD wetlands increased from low fragility in 2010 to general fragility in 2011-2013,and to high fragility in 2014,reflecting the fact that the wetland ecological condition was degenerating from 2010 to 2014.The ecological vulnerability status then turned back into general fragility during 2015-2017,indicating that the ecological situation of the BYD wetlands was starting to improve.However,the ecological status of the BYD wetlands on the whole is relatively less optimistic.The major factors affecting the ecological vulnerability of the BYD wetlands were found to be industrial smoke and dust emission,wetland water area,ammonia nitrogen,total phosphorus,rate of industrial solid wastes disposed,GDP per capita,etc.This illustrates that it is a systematic project to regulate wetland vulnerability and to protect regional ecological security,which may offer researchers and policy-makers specific clues for concrete interventions.