海参冻干-微波联合干燥技术研究

由于海参离开海水后很快会发生自溶,所以海参一般都是脱水后在市场上流通。传统的海参干制方法耗时太长,而且品质较差;真空冷冻干燥方法可以获得品质优良的海参干制品,但能耗太大。为了缩短冷冻干燥的干燥时间,同时保证海参的干燥质量,将海参真空冷冻干燥至一定含水率,再进行真空微波干燥,并与其他典型干燥方法进行了比较,发现微波-冻干联合干燥方法能有效缩短冻干时间,其产品和常规冻干产品无明显差异。     

肉类发酵菌种真空冷冻干燥保护剂研究进展

直投式肉用发酵剂因其具有使用方便、发酵性能优良等优势而倍受关注,但是菌粉冻干存活率低的问题一度成为阻碍肉类发酵行业发展的壁垒.真空冷冻干燥过程中加入冻干保护剂能有效避免冷冻干燥对菌种的损伤,提高存活率.从肉类发酵剂、直投式肉用发酵剂、真空冷冻干燥技术对细胞损伤机理、冷冻干燥保护剂4个方面综述了冻干保护剂在提高肉类发酵菌...     

干燥方法对白牛肝菌和鸡枞菌品质特性的影响

本研究以白牛肝菌和鸡枞菌为原料,采用微波-热风联合干燥、热风干燥和真空冷冻干燥三种方法对菌菇进行处理,研究干燥方法对菌菇色泽、复水率、质构特性及微观结构等品质特性的影响。结果表明:色泽方面,真空冷冻干燥和微波-热风联合干燥优于热风干燥;复水性方面,真空冷冻干燥法优于微波-热风联合干燥法和热风干燥法,又以鸡枞菌的复水性最佳;质构方面,不同方法干燥后,菌菇硬度、弹性和咀嚼性变化规律相同,各指标强度大小排序为热风干燥 > 微波热风联合干燥 > 真空冷冻干燥;微观结构方面,微波-热风联合干燥和真空冷冻干燥后的菌菇截面呈多孔状,热风干燥菌菇的多孔网状结构不明显。综合考虑,白牛肝菌和鸡枞菌的干燥方法首选真空冷冻干燥,其次为微波-热风联合干燥,不宜选择热风干燥。     

不同干燥方法对黄绿蜜环菌品质的影响

研究自然晒干、热风干燥、真空冷冻干燥和真空干燥4种不同的干燥方法对黄绿蜜环菌外观品质、物理性质和营养成分的影响。结果表明:外观品质方面,真空冷冻干燥产品效果最好;真空干燥和鼓风干燥其次;自然晒干对黄绿蜜环菌影响最大。物理性质方面,复水比大小依次为:真空冷冻干燥真空干燥自然晒干热风干燥。营养成分方面,不同干燥处理后,黄绿蜜环菌营养成分均有所降低,其中真空冷冻干燥对黄绿蜜环菌营养成分的破坏最小;真空干燥和自然晒干其次;而热风干燥除总糖外,其他各营养成分损失最大。综合来看,真空冷冻干燥为最佳干燥方法。     

即食海参优势腐败菌群体感应信号分子识别

为了研究即食海参革兰氏阴性腐败菌是否具有以群体感应介导的腐败特性,以根癌农杆菌CF11为指示菌,检测即食海参优势腐败菌H-3产生AHLs信号分子,结果 H-3在菌体生长至20 h时的AHLs活性最高。质谱分析发现H-3产生N-己酰基-高丝氨酸内酯(C6-HSL)。添加适量外源信号分子能促进菌株H-3生物膜的形成,降解H-3的AHLs后可阻断其蛋白酶的产生。经16S r DNA鉴定该菌为即食海参优势腐败菌。结论:即食海参优势腐败菌存在以AHLs介导的群体感应系统,与即食海参的腐败密切相关。     

浅析真空冷冻干燥生鲜面条

干燥是保持物质不致腐败变质、便于储藏、物流的方法之一。干燥的方法有多种,如晒干、风干、煮干、油炸、烘干、喷雾干燥和真空冷冻干燥等。而干燥工艺和设备的选择对食品产品的营养、色香味有较大影响,采用真空冷冻干燥技术可保存新鲜食品的色、香、味及维生素C等营养物质,能获得较好的食品质量。阐述了该项技术在冷冻干燥生鲜面条中的应用,浅析真空冷冻干燥生鲜面条的冻干机理和冻干特点。     

优良己酸菌分离培养及冷干保藏条件研究

以大曲酒窖窖泥为材料,对己酸菌进行了分离纯化,并对己酸菌菌种的真空冷冻干燥保藏方法进行了研究,初步确定了菌种冻干保藏的预冻温度及保护剂浓度。比较了己酸菌不同保存方式的保藏效果,实验表明采用冷冻干燥保藏法长期保藏菌种效果良好。     

长双歧杆菌活菌制剂下游制备方法优化

对长双歧杆菌活菌制剂制备中的菌体收集、保护剂和冷冻干燥工艺进行研究,优化了菌体收集及冷冻干燥工艺条件,比选出有效的长双歧杆菌保护剂。采用低温离心收集菌体、添加保护剂及真空冷冻干燥获得了适合的长双歧杆菌活菌制剂下游制备方法。     

真空冷冻干燥工艺参数对植物乳杆菌MA2活性的影响

试验主要研究了预冻温度、预冻时间、保护剂配方、保护剂与菌泥比例、物料厚度等真空冷冻干燥工艺参数对植物乳杆菌MA2活性的影响,并对真空冷冻干燥过程中菌粉的含水量进行了动态监测,绘制了物料升温曲线图,最终确定了合适的真空冷冻干燥工艺为预冻温度70℃;预冻时间2h;保护剂与菌泥的比例为1∶3;保护剂配方为脱脂奶粉10％,海藻糖1.5％,甘油0.5％,山梨醇2％,麦芽糊精1％;冻干厚度为1.5cm,该工艺条件下植物乳杆菌MA2真空冷冻干燥后的菌体存活率达61％,活菌数为1.50× 1012cfu/g.经复水试验证明,真空冷冻干燥后的菌体活性保持良好,证明该工艺具有良好的应用推广前景.     

超声预处理对真空冷冻干燥猕猴桃片品质的改善作用

目的 以“海沃德”猕猴桃为原料,采用超声预处理改善真空冷冻干燥猕猴桃片的品质。方法 分别采用不同功率（60 W,120 W,180 W,240 W,300 W）和时间（1 min,5 min,10 min,15 min,20 min）的超声波预处理猕猴桃,经真空冷冻干燥制成真空冷冻干燥猕猴桃片,分析真空冷冻干燥果片的水分含量、可溶性糖、可滴定酸、维生素C含量、水分活度、色度等指标,探讨超声预处理对真空冷冻干燥果片品质的影响规律。结果 超声功率为60 W~180 W时,真空冷冻干燥猕猴桃片的含水量提高2.51%~13.70%;超声时间为1 min~10 min时,含水量提高9.23%~11.75%。与空白相比,所有超声组的可溶性糖含量、可滴定酸含量、糖酸比均略有提高,但维生素C含量平均下降9.66%。超声预处理显著降低真空冷冻干燥猕猴桃片的水分活度,60 W~300 W超声组的水分活度下降4.29% ~20.86%;1 min~20 min超声组的真空冷冻干燥猕猴桃片水分活度下降4.91%~15.34%。所有超声组的a*值均下降,显著低于空白,其中300 W超声波使a*值下降25.08%,超声冻干果片颜色更绿。结论 猕猴桃在真空冷冻干燥加工之前,使用功率120 W ~240 W和时间1 min ~5 min超声波进行预处理,有助于改善真空冷冻干燥猕猴桃片的整体品质。     

海参内脏的活性成分、保健功能与开发研究进展

海参作为中国的传统补品,具有增强免疫力、抗肿瘤、抗病毒、养颜美容等作用。海参的主要食用部位为海参体壁,因此对海参的研究也多聚焦在海参体壁活性物质上。海参加工中的副产物海参内脏则多被废弃,利用率低,国内外对其研究也较少,已开发的相关产品更是微乎其微。然而海参内脏除含有与体壁相似的化学成分外,还富含牛磺酸、精氨酸、磷脂、不饱和脂肪酸以及各种高活性微量元素、色素、活性酶和功能菌,海参内脏的食用价值和药用价值在一定范围内高于海参体壁。目前对海参内脏活性物质认识的缺乏和忽视,已造成资源严重浪费和流失。基于希望对天然资源的充分合理利用,对海参内脏具有的化学成分、生物活性以及活性物质的提取分离进行介绍,为海参内脏相关食品、保健品和新药的研究与开发提供依据。     

菌酶联用处理对刺参体壁降解效果及风味特性的影响

目的：为探究不同菌酶联用处理方式对刺参体壁降解效果及产物风味特性的影响。方法：采用不同处理方式：单菌（J）、单酶（M）、先菌后酶（JM）、先酶后菌（MJ）、菌酶同用（T）（菌为解淀粉芽孢杆菌,酶为复合蛋白酶）对刺参体壁进行降解,测定降解液中氨基酸组成、多肽相对分子质量分布等理化指标,同时利用气相色谱-离子迁移谱（GC-IMS）和电子舌分别测定不同处理方式下刺参体壁降解产物的挥发性和非挥发性风味成分。结果：刺参体壁经菌酶联合（JM、MJ、T）处理后,与单独作用相比,相对分子质量>1000 Da的肽含量减少了60.29%,<500 Da的肽含量增加了33.36%,联合处理下游离氨基酸总量与风味核苷酸总量的平均值较菌酶单独作用时分别增加了1.3倍和4.1倍,降解液中挥发性化合物由未处理时的43种增加到联合处理后的67种。表明刺参体壁经联合处理后风味成分变得更加复杂,联合处理可以降低小分子醛、不饱和醛等腥味成分的含量、增加酯类等愉悦性成分的含量。其中,多肽含量最高的处理组是M(34.770 mg/g),其次是JM(30.733 mg/g),感官评分最高的是JM(66.67分),其次...     

Bactericidal paper impregnated with silver nanoparticles for point-of-use water treatment

There is an urgent need for cheap point-of-use methods to purify drinking water. We describe a method to deactivate pathogenic bacteria by percolation through a paper sheet containing silver nanoparticles. The silver nanoparticles are deposited by the in situ reduction of silver nitrate on the cellulose fibers of an absorbent blotting paper sheet. The aim is to achieve inactivation of bacteria during percolation through the sheet, rather than removal of bacteria from the effluent by filtration. The silver-nanoparticle containing (AgNP) papers were tested for performance in the laboratory with respect to bacteria inactivation and silver leaching as suspensions of bacteria percolated through the paper. The AgNP sheets exhibited antibacterial properties toward suspensions of Escherichia coli and Enterococcus faecalis, with log reduction values in the effluent of over log 6 and log 3, respectively. The silver loss from the AgNP sheets was minimal, with values under 0.1 ppm (the current US EPA and WHO limit for silver in drinking water). These results show promise that percolation of bacterially contaminated water through paper embedded with silver nanoparticles could be an effective emergency water treatment.     

市售干海参中非法添加的蔗糖和无机成分的X射线衍射质量控制

粉末X射线衍射(PXRD)是一种简单快捷的无损检测技术,该技术罕有海参及其非法添加剂的检测应用。本研究建立一种干海参中非法添加糖分的PXRD鉴定方法。对随机采购的8种市售干海参刺参(呈甄干海参、棒棰岛干海参、辽刺参、精品海参、俄罗斯海参、野生海参、财神岛干海参、长生岛干海参),获得PXRD谱及特征标记峰。运用有机分子晶体的PXRD谱模拟方法,鉴定糖分来源及其含量。结果表明:海参体壁没有任何种类的有机分子晶体,海参沙嘴主要成分为具有菱方结构的碳酸镁钙(Mg0.1Ca0.9CO3),人为掺入的蔗糖能够在干海参中结晶,形成能被PXRD技术探测的系列衍射峰。辽刺参中掺有糖分,被鉴定为蔗糖,其含量达4.45 g/100 g;呈甄干海参、棒棰岛干海参、辽刺参、精品海参、俄罗斯海参、野生海参、财神岛干海参、长生岛干海参中盐分含量分别为:3.62 g/100 g、4.40 g/100 g、3.55 g/100 g、2.87 g/100 g、1.60 g/100 g、15.56 g/100 g、2.35 g/100 g、3.90 g/100 g;呈甄干海参、棒棰岛干海参、精品海参、俄罗斯海参、野生海参、财神岛干海参、长生岛干海参中含沙量分别为:2.12 g/100 g、0.62g/100 g、0.14 g/100 g、0.22 g/100 g、0.38 g/100 g、0.85 g/100 g、0.90 g/100 g。因此,PXRD技术适合于市售干海参糖分和盐分的质量控制。     

傅立叶变换红外光谱法快速鉴别海参质量

利用傅立叶变换红外光谱(FTIR)快速鉴别了两种不同品质的海参,结果表明,优质海参与劣质海参的红外光谱图有明显的区别,利用谱图峰的波数位置及谱峰强度可鉴别海参质量的优劣。此方法具有简便、快速、用样品量少等特点。     

海参贮藏保鲜机理及保鲜技术研究进展

海参具有丰富的营养价值和食疗养生功能。在市场流通和贮藏过程中,海参自溶和微生物生长易导致品质劣化,造成巨大的经济损失。明确海参贮藏保鲜过程中内源酶和微生物的作用机理,是阐释海参品质变化的核心,对设计开发新型海参贮藏保鲜技术具有理论指导意义,是关乎海参产业发展的关键技术问题。本文概述海参贮藏保鲜机理,归纳海参相关保鲜技术,提出深入研究的建议,并对未来发展趋势予以展望,以期为海参行业高质量发展提供更强有力的理论支撑。     

海参多糖生物学活性及其作用机制研究进展

海参中多糖含量丰富,占海参干质量6%以上,具有抗肿瘤、抗凝血、抗氧化及抗帕金森病等多种生物学活性,在保健食品和药品开发方面具有广阔的应用前景。海参多糖的结构特性如分子质量、硫酸化模式及硫酸基含量等对其生物学活性具有很大影响,因此研究海参多糖结构对揭示其生物学活性及作用机制具有重要意义。本文在介绍海参多糖结构特性的基础上,重点综述其生物学活性及作用机制,同时总结海参多糖结构对其生物学活性的影响,最后对海参多糖的发展前景进行展望,以期为海参多糖的精深加工和应用提供理论支持。     

海参中有毒有害物质的检测方法研究进展

海参因含有多糖、海参肽、海参皂苷、脑苷脂、神经节苷脂等多种生物活性物质,具有提高免疫活性、抗氧化、抗衰老、降血脂、降血糖、改善认知、抗疲劳、抗肿瘤、抗癌、抗真菌等功能,成为广大研究者的研究热点之一,其相关产品和功能也不断地被开发和利用,但对海参中可能残留的有毒有害物质及其检测方法研究较少。本文综合现有的国家或行业标准以及研究报道,就海参中非法添加物、污染物(包括重金属、多氯联苯和多环芳烃)、兽药残留和农药残留的检测方法进行概述和讨论,旨在为海参及其相关产品提供质量安全检测参考。     

Effects of small-diameter silver nanoparticles on microbial load in cow milk

Controlling bacterial growth in fluid milk is of economic interest, and supplemental methods to stop or reduce bacterial growth before and during the cooling chain may be valuable. Silver is effective in controlling growth of single-celled organisms, but has no effect on tissue cells. Smaller diameter (6-8 nm) silver nanoparticles were produced, with purity over 99.99% (no chemical reaction used in the process), by using a terminated gas condensation principle. The first trial investigated effects of time, temperature, and accelerating voltages on total aerobic bacteria count in control milk and milk treated with silver nanoparticles. Metal braids were coated with silver nanoparticles using 3 accelerating voltages, 0, 100, and 200V, the results of which indicated that the braids coated using 100V (AgNP100) were optimal. The AgNP100 particles were effective at all treatment temperatures and durations except for 10h, which indicated that the treated milk could be used after 10h for other dairy products such as yogurt, which require microbial activity. The second experiment investigated the effects of silver nanoparticles on counts of yeasts and molds, coliform bacteria, Escherichia coli, and Staphylococcus aureus in cow milk by treating milk with AgNP100 braids at 22 °C for 1h. Inductively coupled plasma mass spectrometry analyses indicated that the maximum amount of silver found in the AgNP100-treated milk was 6.1μg/L, which is below the safety limits. Counts in milk samples containing the nanoparticle-coated braids were lower for all yeasts and molds and bacteria investigated compared with the control milk samples, which were kept under the same conditions but without the braids. The differences were significant for coliforms, Escherichia coli, and Staphylococcus aureus but not for yeasts and molds, although ranking of the counts (AgNP100 < initial load < control) were the same for all microorganisms. Small-diameter, silver nanoparticle-coated braids can stop or reduce bacterial growth in fluid milk. Silver nanoparticles inhibited microbial growth and may be useful in complementing the cooling chain and the thermal processes. These results warrant more research on the sensory properties and long-term safety of the use of silver nanoparticles in dairy products.     

Reduction of the spoilage-related microflora in absorbent pads by silver nanotechnology during modified atmosphere packaging of beef meat

Silver-based antibacterial hybrid materials have been developed by in situ reduction of silver nitrate (1%) adsorbed on cellulose fibers by thermal and UV treatments. Microscopy revealed that the silver nanoparticles were dispersed and regular in shape. Migrated silver ions achieved 60 ppm in beef meat exudates. The ability of the silver-loaded absorbent pads to lower microbial contamination of exuded fluids was studied during storage of beef meat in modified atmosphere packaging. Cellulose-silver hybrid materials reduced the levels of the major microbial groups (total aerobic bacteria, lactic acid bacteria, Pseudomonas spp., and Enterobacteriaceae) present in the absorbent pads by an average of 1 log CFU/g during the entire storage period. The levels of total aerobic bacteria and Pseudomonas spp. were significantly reduced in the presence of silver ions, whereas lactic acid bacteria were less sensitive and not significantly affected. Enterobacteriaceae levels remained under the detection limit when silver was present. Neither the color of the meat nor the microbial loads were markedly affected by the presence of the silver-based antimicrobial hybrid materials.