A case study of continental shelf waves in the northwestern South China Sea induced by winter storms in 2021

This study aims to investigate characteristics of continental shelf wave(CSW)on the northwestern continental shelf of the South China Sea(SCS)induced by winter storms in 2021.Mooring and cruise observations,tidal gauge data at stations Hong Kong,Zhapo and Qinglan and sea surface wind data from January 1 to February 28,2021 are used to examine the relationship between along-shelf wind and sea level fluctuation.Two events of CSWs driven by the along-shelf sea surface wind are detected from wavelet spectra of tidal gauge data.The signals are triply peaked at periods of 56 h,94 h and 180 h,propagating along the coast with phase speed ranging from 6.9 m/s to18.9 m/s.The dispersion relation shows their property of the Kelvin mode of CSW.We develop a simple method to estimate amplitude of sea surface fluctuation by along-shelf wind.The results are comparable with the observation data,suggesting it is effective.The mode 2 CSWs fits very well with the mooring current velocity data.The results from rare current help to understand wave-current interaction in the northwestern SCS.

Contributors to tidal duration asymmetry with varied coastline configurations on western shelf of Yellow Sea

Coastal management in China is confronted with an urgent choice between natural restoration and maintenance of existing seawalls and reclaimed land for economic development.A key criterion for making this decision is the resilience to coastal flooding,which depends on the ability to predict tidal level.Tidal duration asymmetry(TDA)is a key parameter in determination of the arrival and duration of flood tides.This study selected the western inner shelf of the Yellow Sea(WYS)as the study area and investigated the responses of TDA to different shoreline configurations and relative sea level rise.The responses of TDA to shoreline reconstruction yielded spatial variability locally and remotely.In the nearshore area,the responses of TDA to the complex ocean environment mainly originated from the combined functions of reflection,bottom friction,and advection,which controlled the energy transfer from M2 or S2 constituents to their overtides or compound tides.The sensitivity of TDA to coastline typologies was not limited to coastal waters but could stretch over the entire inner shelf.The vulnerability of tidal responses was due to the displacement of the M2 amphidrome of the Kelvin wave on the WYS,which in turn changed tidal energy fluxes over the regime.The relative sea level rise could intensify the feedback of TDA to seawalls and land reclamation.

The variation in basal channels and basal melt rates of Pine Island Ice Shelf

In recent years,there has been a significant acceleration in the thinning,calving and retreat of the Pine Island Ice Shelf(PIIS).The basal channels,results of enhanced basal melting,have the potential to significantly impact the stability of the PIIS.In this study,we used a variety of remote sensing data,including Landsat,REMA DEM,ICESat-1 and ICESat-2 satellite altimetry observations,and Ice Bridge airborne measurements,to study the spatiotemporal changes in the basal channels from 2003 to 2020 and basal melt rate from 2010 to 2017 of the PIIS under the Eulerian framework.We found that the basal channels are highly developed in the PIIS,with a total length exceeding 450 km.Most of the basal channels are ocean-sourced or groundingline-sourced basal channels,caused by the rapid melting under the ice shelf or near the groundingline.A raised seabed prevented warm water intrusion into the eastern branch of the PIIS,resulting in a lower basal melt rate in that area.In contrast,a deepsea trough facilitates warm seawater into the mainstream and the western branch of the PIIS,resulting in a higher basal melt rate in the main-stream,and the surface elevation changes above the basal channels of the mainstream and western branch are more significant.The El Ni?o event in 2015–2016 possibly slowed down the basal melting of the PIIS by modulating wind field,surface sea temperature and depth seawater temperature.Ocean and atmospheric changes were driven by El Ni?o,which can further explain and confirm the changes in the basal melting of the PIIS.

Deep Learning-Based Classification of Rotten Fruits and Identification of Shelf Life

The freshness of fruits is considered to be one of the essential characteristics for consumers in determining their quality,flavor and nutritional value.The primary need for identifying rotten fruits is to ensure that only fresh and high-quality fruits are sold to consumers.The impact of rotten fruits can foster harmful bacteria,molds and other microorganisms that can cause food poisoning and other illnesses to the consumers.The overall purpose of the study is to classify rotten fruits,which can affect the taste,texture,and appearance of other fresh fruits,thereby reducing their shelf life.The agriculture and food industries are increasingly adopting computer vision technology to detect rotten fruits and forecast their shelf life.Hence,this research work mainly focuses on the Convolutional Neural Network’s(CNN)deep learning model,which helps in the classification of rotten fruits.The proposed methodology involves real-time analysis of a dataset of various types of fruits,including apples,bananas,oranges,papayas and guavas.Similarly,machine learningmodels such as GaussianNaïve Bayes(GNB)and random forest are used to predict the fruit’s shelf life.The results obtained from the various pre-trained models for rotten fruit detection are analysed based on an accuracy score to determine the best model.In comparison to other pre-trained models,the visual geometry group16(VGG16)obtained a higher accuracy score of 95%.Likewise,the random forest model delivers a better accuracy score of 88% when compared with GNB in forecasting the fruit’s shelf life.By developing an accurate classification model,only fresh and safe fruits reach consumers,reducing the risks associated with contaminated produce.Thereby,the proposed approach will have a significant impact on the food industry for efficient fruit distribution and also benefit customers to purchase fresh fruits.

Exogenous melatonin improves the chilling tolerance and preharvest fruit shelf life in eggplant by affecting ROS-and senescence-related processes

Low temperature is the most common abiotic stress factors during the eggplant cultivation in solar greenhouses.Melatonin plays important roles in plant resistance to low temperature.However,the role of melatonin in regulating chilling tolerance and extending the preharvest shelf life of eggplant fruits is still unknown.In this study,we investigated the effects of exogenous melatonin on eggplant plants and fruits in response to low temperature.Under simulated low-temperature conditions,exogenous melatonin significantly relieved the chilling symptoms of seedlings by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and relative leakage rates.These reductions were caused by higher superoxide dismutase (SOD) and catalase (CAT) activities and increased endogenous polyamine and melatonin levels compared with those in untreated seedlings.Notably,the expression levels of SOD,CAT1/2,and polyamine synthesis genes (ADC and ODC) were also increased by 100μmol·L~(-1)melatonin,as well as those of genes involved in melatonin synthesis (TDC,T5H,SNAT,ASMT,and COMT) and cold regulation (COR1,CBFa/b,and ZAT2/6/12).To further investigate the effects of melatonin on eggplant leaves and fruits under natural low temperature conditions,100μmol·L~(-1)melatonin was sprayed on the functional leaves at three days before commodity maturation.Melatonin significantly alleviated chilling injury in the leaves and pericarp and extended the preharvest shelf life of the fruit by increasing the expression of COR1,CBF,ZAT2/6/12,and API5 and decreasing the expression of senescence-related genes (NCED1/2 and SAG12).Therefore,100μmol·L~(-1)melatonin improved chilling tolerance and fruit shelf life by upregulating ZAT2/6/12 to affect ROS-and senescence-related processes,which provides a reference for alleviating cold stress and extending the preharvest fruit shelf life in eggplant.

New interpretation on the provenance changes of the upper Pinghu–lower Huagang Formation within Xihu Depression,East China Sea Shelf Basin

Both Pinghu and Huagang formations are important hydrocarbon reservoirs of the Xihu Depression in the East China Sea Shelf Basin.Clarifying the source suppliers and restoring source-to-sink transport routes are of great significance to the future petroleum and gas undertakings.Previous researchers were largely confined by either limitation of geological records,highly dependence on a singular method or low-precision dating techniques.Our study integrated heavy mineral assemblages,geochemical analyses and detrital zircon U-Pb dating to reconstruct multiple source-to-sink pathways,and to provide a better understanding on the provenance evolution for the upper Pinghu–lower Huagang depositions of the Xihu Depression.At least three major provenances have been confirmed and systematically investigated for their separate compositional features.The Hupijiao Uplift(or even farther northern area)was dominated by a major Paleoproterozoic population peaked at ca.1830 Ma along with minor Mesozoic clusters.The Haijiao Uplift to the west and the Yushan Low Uplift to the southwest,on the other hand,generate opposite U-Pb age spectra with apparently larger peaks of Indosinian and Yanshanian-aged zircons.To be noted,both Indosinian and Paleoproterozoic peaks are almost identical in proportion for the Haijiao Uplift.The overall sedimentary pattern of late Eocene-early Oligocene was featured by both spatial and temporal distinction.The Hupijiao Uplift was likely to cast limited impact during the late Eocene,whereas the broad southern Xihu Depression was transported by a large abundance of materials from the nearby Haijiao and Yushan Low Uplifts.The northern source substantially extended its influence to the farther south during the early Oligocene by delivering plentiful sediments of higher-degree metamorphic parent rocks.Combined with the proximal western and southwestern suppliers,the overall Xihu Depression was under control from both distant and local provenances.

Application of seismic sedimentology in characterization of fluvial-deltaic reservoirs in Xihu sag, East China Sea shelf basin

The fluvial-deltaic reservoirs of the Oligocene Huagang Formation in the Xihu sag of the East China Sea shelf basin reflect rapid lateral change in sedimentary facies and poor morphology of conventional slice attributes,which bring difficulties to the reservoir prediction for subsequent exploration and development of lithologic reservoirs.The traditional seismic sedimentology technology is optimized by applying the characteristic technologies such as frequency-boosting interpretation,inversion-conventional–90°phase shift joint construction of seismic lithologic bodies,nonlinear slices,paleogeomorphology restoration,and multi-attribute fusion,to obtain typical slice attributes,which are conducive to geological form description and sedimentary interpretation.The Huagang Formation developed three types of sedimentary bodies:braided river,meandering river and shallow water delta,and the vertical sedimentary evolution was controlled by the mid-term base-level cycle and paleogeomorphology.In the early–middle stage of the mid-term base-level ascending cycle,braided channel deposits were dominant,and vertical superimposed sand bodies were developed.In the late stage of the ascending half-cycle and the early stage of the descending half-cycle,meandering river deposits were dominant,and isolated sand bodies were developed.In the middle–late stage of the descending half-cycle,shallow-water delta deposits were dominant,and migratory medium–thick sand bodies were developed.Restricted paleogeomorphology controlled the sand body distribution,while non-restricted paleogeomorphology had little effect on the sand body distribution.Based on reservoir characterization,the fault sealing type and reservoir updip pinch-out type structural lithological traps are proposed as the main directions for future exploration and development in the Xihu sag.

The Processes-Based Attributes of Four Major Surface Melting Events over the Antarctic Ross Ice Shelf

The Ross-Amundsen sector is experiencing an accelerating warming trend and a more intensive advective influx of marine air streams.As a result,massive surface melting events of the ice shelf are occurring more frequently,which puts the West Antarctica Ice Sheet at greater risk of degradation.This study shows the connection between surface melting and the prominent intrusion of warm and humid air flows from lower latitudes.By applying the Climate Feedback-Response Analysis Method(CFRAM),the temporal surge of the downward longwave(LW)fluxes over the surface of the Ross Ice Shelf(RIS)and adjacent regions are identified for four historically massive RIS surface melting events.The melting events are decomposed to identify which physical mechanisms are the main contributors.We found that intrusions of warm and humid airflow from lower latitudes are conducive to warm air temperature and water vapor anomalies,as well as cloud development.These changes exert a combined impact on the abnormal enhancement of the downward LW surface radiative fluxes,significantly contributing to surface warming and the resultant massive melting of ice.

Predicting impacts of climate change on the biogeographic patterns of representative species richness in Prydz Bay-Amery Ice Shelf

The research on the biological ecology of the Prydz Bay-Amery Ice Shelf in East Antarctica is inadequate under the increasing threat from climate change,especially for Antarctic fish and krill.The Dynamic Bioclimatic Envelope Model(DBEM)has been widely used in predicting the variation of species distribution and abundance in ocean and land under climate change;it can quantify the spatiotemporal changes of multi population under different climate emission scenarios by identifying the environmental preferences of species.The species richness and geographical pattern of six Antarctic representative species around Prydz Bay-Amery ice shelf were studied under RCP 8.5 and RCP 2.6 emission scenarios from 1970 to 2060 using Geophysical Fluid Dynamics Laboratory(GFDL),Institut Pierre Simon Laplace(IPSL),and Max Planck Institute(MPI)earth system models.The results showed that the species richness decreased as a whole,and the latitude gradient moved to the pole.The reason is that ocean warming,sea ice melting,and human activities accelerate the distribution changes of species biogeographical pattern,and the habitat range of krill,silverfish,and other organisms is gradually limited,which further leads to the change of species composition and the decrease of biomass.It is obvious that priority should be given to Prydz Bay-Amery ice shelf in the planning of Marine Protected Areas(MPAs)in East Antarctica.

Clay minerals and elemental composition of sediments on different sedimentary units in the northern East China Sea shelf:provenance tracing and genetic mechanism analysis

The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediments in the northern ECS shelf are distributed in a ring-shaped distribution centered on the southwestern Cheju Island Mud.From the inside to the outside,the grain size goes from fine to coarse.Aside from the“grain size effect”,hydrodynamic sorting and mineral composition are important restrictions on the content of rare earth elements(REEs).Based on the grain size,REEs,and clay mineral composition of 300 surface sediments,as well as the sedimentary genesis,the northern ECS shelf is divided into three geochemical zones:southwestern Cheju Island Mud Area(ZoneⅠ),Changjiang Shoal Sand Ridges(ZoneⅡ-1),Sand Ridges of the East China Sea shelf(ZoneⅡ-2).The northern ECS shelf is mostly impacted by Chinese mainland rivers(the Changjiang River and Huanghe River),and the provenance and transport mechanism of sediments of different grain sizes is diverse.The bulk sediments come primarily from the Changjiang River,with some material from the Huanghe River carried by the Yellow Sea Coastal Current and the North Jiangsu Coastal Current,and less from Korean rivers.Among them,surface sediments in the southwestern Cheju Island Mud Area(ZoneⅠ)come mostly from the Changjiang River and partly from the Huanghe River.It was formed by the counterclockwise rotating cold eddies in the northern ECS shelf,which caused the sedimentation and accumulation of the fine-grained sediments of the Changjiang River and the Huanghe River.The Changjiang Shoal Sand Ridges(ZoneⅡ-1)were developed during the early-middle Holocene sea-level highstand.It is the modern tidal sand ridge sediment formed by intense hydrodynamic action under the influence of the Yellow Sea Coastal Current,North Jiangsu Coastal Current,and Changjiang Diluted Water.The surface sediments mainly originate from the Changjiang River and Huanghe River,with the Changjiang River dominating,and the Korean River(Hanjiang River)influencing just a few stations.Sand Ridges of the East China Sea shelf(ZoneⅡ-2)are the relict sediments of the paleo-Changjiang River created by sea invasion at the end of the Last Deglaciation in the Epipleistocene.The clay mineral composition of the surface sediments in the study area is just dominated by the Changjiang River,with the North Jiangsu Coastal Current and the Changjiang Diluted Water as the main transporting currents.

The morphological changes of basal channels based on multisource remote sensing data at the Pine Island Ice Shelf

The basal channel is a detailed morphological feature of the ice shelf caused by uneven basal melting.This kind of specifically morphology is widely distributed in polar ice shelves.It is an important research object of sea-ice interaction and plays a vital role in studying the relationship between the ice sheet/ice shelf and global warming.In this paper,high-resolution remote sensing image and ice penetration data were combined to extract the basal channel of the Pine Island Ice Shelf.The depth variation of Pine Island Ice Shelf in the recent 20 years was analyzed and discussed by using ICESat-1,ICESat-2,and IceBridge data.Combined with relevant marine meteorological elements(sea surface temperature,surface melting days,circumpolar deep water and wind)to analyze the basal channel changes,the redistribution of ocean heat is considered to be the most important factor affecting the evolution and development of the basal channel.

Origin of hydrocarbon fluids and discussion of abnormal carbon isotopic compositions in the Lishui-Jiaojiang Sag,East China Sea Shelf Basin

The hydrocarbon gases in the L1 gas field of the Lishui-Jiaojiang Sag have been commonly interpreted to be an accumulation of pure sapropelic-type thermogenic gas.In this study,chemical components,stable isotopic compositions,and light hydrocarbons were utilized to shed light on the origins of the hydrocarbon fluids in the L1gas pool.The hydrocarbon fluids in the L1 gas pool are proposed to be a mixture of three unique components:mid-maturity oil from the middle Paleocene coastal marine Lingfeng source rock,oil-associated(late oil window)gas generated from the lower Paleocene lacustrine Yueguifeng source rock,and primary microbial gas from the paralic deposits of the upper Paleocene Mingyuefeng source rock.Here,for the first time,the hydrocarbon gases in the L1 gas pool are diagnosed as mixed oil-associated sapropelic-type gas and microbial gas via four pieces of principal evidence:(1)The abnormal carbon isotopic distributions of all methane homologues from C_(1)(CH_(4)or methane)to C_(5)(C_(5)H_(12)or pentane)shown in the Chung plot;(2)the diagnostic~(13)C-depleted C_(1)compared with the thermogenic sapropelic-type gas model,whileδ^(13)C_(2)(C_(2)H_(6)or ethane)andδ^(13)C_(3)(C_(3)H_(8)or propane)both fit perfectly;(3)the excellent agreement of the calculated carbon isotopic compositions of the pure thermogenic gas with the results of the thermal simulated gas from the type-II1 kerogen-rich Yueguifeng source rock;and(4)the oil-associated gas inferred from various binary genetic diagrams with an abnormally elevated gas oil ratio.Overall,the natural gases of the L1 gas pool were quantified in this study to comprise approximately 13%microbial gas,nearly 48%oil-associated sapropelic-type gas,and 39%of nonhydrocarbon gas.The microbial gas is interpreted to have been codeposited and entrained in the humic-kerogen-rich Mingyuefeng Formation under favorable lowtemperature conditions during the late Paleocene-middle Eocene.The microbial gas subsequently leaked into the structurally and stratigraphically complex L1 trap with oil-associated sapropelic-type gas from the Yueguifeng source rock during the late Eocene-Oligocene uplifting event.A small amount of humic-kerogen-generated oil in the L1 gas pool is most likely to be derived from the underlying Lingfeng source rock.The detailed geological and geochemical considerations of source rocks are discussed to explain the accumulation history of hydrocarbon fluids in the L1 gas pool.This paper,therefore,represents an effort to increase the awareness of the pitfalls of various genetic diagrams,and an integrated geochemical and geological approach is required for hydrocarbonsource correlation.

Mesozooplankton distribution and diversity from the Bering Sea shelf to the Chukchi Sea

In recent decades,environmental changes in the Arctic have aroused widespread concern around the world.To better understand ecology issues such as ecosystem dynamics,the Arctic and the subarctic regions were integrated as the“pan-Arctic”region.In this study,mesozooplankton were sampled from the Bering Sea shelf to the northern Chukchi Sea during the 10th Chinese National Arctic Research Expedition in 2019.Based on the species composition and abundance,three geographical communities were identified:the Bering Sea shelf community(BSS),the Bering Strait transitional community(BST),and the Chukchi Sea shelf community(CSS).The BSS was characterized by Bering Sea oceanic species such as Eucalanus bungii;the BST was mainly composed of the pan-Arctic distributed Calanus glacialis,meroplankton of benthos,and neritic species such as Centropages abdominalis;copepods,especially the copepodite of C.glacialis,were predominant in the CSS community.The BSS community structure was strongly affected by the inflow of Bering Shelf Water,while those of BST and CSS were determined by the recruitment of local species.The zooplankton community structure is influenced by both advection and environmental changes such as warming and a prolonged productivity period.Here,it was difficult to distinguish the changes induced by climate change from the effects of the Bering Sea Water.The key to solving this problem is the accumulation of comparable data,which requires continuous monitoring of key species such as C.glacialis and Calanus hyperboreus.

超高压处理对鲜榨复配果汁品质及货架期的影响

为使经杀菌处理后果汁的活性成分和风味物质更接近原鲜榨果汁,本研究以猕猴桃、菠萝、芒果为原料制备复配果汁,对比超高压处理与热处理(85℃、5 min)两种杀菌方式对鲜榨复配果汁品质及货架期的影响。结果表明:复配果汁比例V菠萝原浆:V猕猴桃原浆:V芒果原浆=4:2:4时,与传统热处理相比,在450 MPa、25℃、15 min超高压条件下处理,pH、b^(*)值、可溶性固形物无明显差异(P>0.05),维生素C含量损失减少12.1%、多酚含量损失减少17.5%,品质更接近于未处理果汁;通过对复配果汁主要挥发性成分进行分析,烯类、酯类、醇类、酮类、醛类等风味物质的损失显著小于(P<0.05)热处理,且蒸煮味物质糠醛没有生成,丙酮和1-辛烯-3-酮相对含量分别减少68.4%、41.4%;菌落总数、霉菌和酵母菌杀菌效果均符合饮料现行有效卫生标准;通过Q_(10)模型对货架期进行预测,在4℃条件下储藏,其货架期可达到103 d。综上,超高压处理鲜榨复配果汁在有效杀灭微生物的同时更利于复配果汁保持天然品质及其货架期。

临期盒装豆腐腐败菌鉴定及抑菌效果评价

【目的】探究临期盒装豆腐优势腐败菌及对其抑制效果,延长盒装豆腐货架期。【方法】以临期盒装老豆腐和内酯豆腐为研究对象,分离优势腐败菌,并通过16S rDNA全序列分析法对腐败菌进行鉴定。分别添加不同质量浓度的山梨酸钾、脱氢乙酸钠、乳酸链球菌素单一组及3种防腐剂的复配组到样品中,采用加速试验,以抑菌率为指标,通过响应面法确定最佳复配防腐剂配方和质量浓度。【结果】临期盒装豆腐中的优势腐败菌为植生拉乌尔菌(Raoultella planticola)和沃纳利葡萄球菌(Staphylococcus warneri)。单一防腐剂的抑菌率随质量浓度的增加而增加,而复配防腐剂的抑菌效果更好。当山梨酸钾为0.21 g·L^(-1)、脱氢乙酸钠为0.15 g·L^(-1)、乳酸链球菌素为0.17 g·L^(-1)时,对植生拉乌尔菌的抑菌率最高,为25.48%;当山梨酸钾为0.36 g·L^(-1)、脱氢乙酸钠为0.11 g·L^(-1)、乳酸链球菌素为0.10 g·L^(-1)时,对沃纳利葡萄球菌的抑菌率最高,为32.07%;当山梨酸钾为0.29 g·L^(-1)、脱氢乙酸钠为0.03 g·L^(-1)、乳酸链球菌素为0.01 g·L^(-1)时,该复配防腐剂对2种腐败菌均有较好的抑菌效果,抑菌率分别为25.17%和32.42%;将该复配防腐剂添加到回接腐败菌的盒装豆腐中,并于37℃下进行储藏,处理后的盒装豆腐货架期相应延长2 d,经测算相当于在0~4℃下货架期延长7 d。【结论】在加速试验条件下,复配防腐剂可以有效抑制临期盒装豆腐中优势腐败菌,延长货架期。

采前氯化钙和水杨酸处理对蟠枣采后贮藏品质的影响

为探究采前处理对蟠枣果实采后贮藏品质的影响,以新疆主栽鲜食品种蟠枣为研究对象,分别于果实花期、幼果期、膨大期、着色期采用清水(CK)、10 g/L氯化钙(CaCl_(2))、100 mmol/L水杨酸(SA)和10 g/L CaCl_(2)+100 mmol/L SA进行采前喷施处理,采收后置于常温货架贮藏,每天统计果实的转红率、转红指数、腐烂率和失重率,测定果实的可溶性固形物含量、硬度和色泽等指标。结果表明:采前喷施CaCl_(2)、SA和CaCl_(2)+SA均可一定程度上抑制蟠枣的转红和腐烂,使其保持较低的失重率,使果实维持较高的可溶性固形物含量和硬度,保持较好的色泽,其中,10 g/L CaCl_(2)+100 mmol/L SA采前处理效果最佳,常温货架8 d时,果实的转红率和腐烂率分别较对照低23.34个百分点和36.66个百分点,失重率仅为1.68%,果实可溶性固形物含量维持在21.47%,硬度为9.45 kg/cm^(2),保持较好的商品性。综上,采前喷施10 g/L CaCl_(2)+100 mmol/L SA能有效保持蟠枣采后贮藏品质。

陈皮牛肉预制菜品质的研究

预制菜是采用各种食材配以辅料,依据现代化标准加工制作而成的成品或半成品,经简易处理便可食用。将传统菜肴陈皮牛肉制作成预制菜不仅能适应当前社会发展的需要,而且能丰富现有预制菜的种类,对预制菜的长远发展具有重要意义。为探究陈皮牛肉预制菜的可行性,文章通过感官评价、脂肪氧化程度、质构、挥发性风味成分等研究陈皮牛肉预制菜的不同包装方式、储存方式、货架期及品质。结果表明,陈皮牛肉预制菜在料液混合包装方式下冷冻保存3 d时感官评价最佳,脂肪氧化程度低,保持较高的食用品质,在此条件下测得其风味物质种类繁多,主要包括醛类、酯类、酮类、醇类、烯烃类等化合物,硫代巴比妥酸反应物值接近于1.0 mg/kg,预制菜的质构等品质接近于传统陈皮牛肉菜肴。

《血液储存标准》修订的思考与启示

国家卫生健康委员会新近正式批准发布的卫生行业标准WS 399-2023《血液储存标准》是WS 399-2012《血液储存要求》的最新修订版本,主要规定了全血、红细胞、血小板、粒细胞、血浆、辐照血等的储存要求,适用于采供血机构和医疗机构,是安全用血的基础和保障。

复合蔬菜汁部分替代亚硝酸盐对鲜烧鸡保质期的影响

文章主要研究了复配的天然蔬菜汁部分替代亚硝酸盐对鲜烧鸡保质期的影响。以挥发性盐基氮(TVB-N)值、pH值和色差值等指标进行单因素试验,确定各因素的最佳范围;在单因素试验的基础上选择3个水平进行正交试验,得出复合蔬菜汁的最佳配比。结果表明,蔬菜汁添加量在10%~20%之间,胡萝卜汁、芹菜汁和亚硝酸盐的配比为10%胡萝卜汁+20%芹菜汁+0.005%亚硝酸盐时,防腐效果最佳。在常温贮存8 d后,鲜烧鸡的色泽、感官品质较对照组有明显差异。此时烧鸡的TVB-N值为13.085 1 mg/100 g,硫代巴比妥酸(TBA)值为0.377 6 mg/kg,亚硝酸盐残留量为8.542 mg/kg,均低于国家标准。结果表明,利用天然蔬菜汁部分替代亚硝酸盐在传统肉制品中应用,加工方式绿色健康,具有广阔的前景。

基于低场核磁共振的预包装即食牛肉保质期预测模型研究

目的:开展预包装即食牛肉保质期快速、准确和无损的预测方法研究,对于保障产品货架期安全具有重要意义。方法:以预包装即食牛肉为分析对象,采集样品低场核磁H质子的T2弛豫时间,建立即食牛肉水分含量定量分析模型,结合样品感官接受性等建立预包装即食牛肉保质期预测模型。结果:预包装即食牛肉低场核磁谱图横向弛豫时间可较好地反映出随着贮存时间的延长航天即食牛肉的品质变化。建立了即食牛肉含水量预测模型,模型的预测误差小于4%;建模集相关系数(r)为0.9405,校正标准差(RMSECV)为34.5,相对分析误差(RPD)为3.1,对10个分别贮存一定时间但未参与建模的样本分别进行距离货架期终点的预测,预测结果与实测值的的相关性达0.99,预测结果的误差范围为0.7%~9.9%,RMSEP为13.6,预测模型的精确度满足货架期预测的精度要求。结论:低场核磁共振技术在预包装即食牛肉产品保质期预测方面具有应用潜力。