番茄红素提取工艺及性质研究

番茄去皮、绞碎后,用丙酮和氯仿(1∶2)提取,经无水硫酸钠脱水后,40℃真空干燥,一次提取率达到91.67%。西红柿中番茄红素的含量为224μg/g。番茄红素最大吸收峰为470nm;太阳光易导致褪色,室内或暗处稳定;4～40℃温度范围内稳定;对pH值变化较敏感。10.9～99mmol/LK+、20.7～69.9mmol/LNa+和8～31.7mmol/LFe3+对该色素几乎无影响;低浓度Ca2+对该色素无影响,但高浓度时有影响;Cu2+对该色素影响较大。Vc、苯甲酸钠及H2O2在一定范围内对色素无影响,而Na2SO3对色素影响较大。     

Temperature Mapping in a Model Food Gel using Magnetic Resonance Imaging

Two dimensional temperature maps of a model food gel (agar, mi-crocrystalline cellulose, and water, 1.95:6.55:200), were obtained by MRI during heating and cooling. The molecular pseudo self-diffusion coefficient of water was used as a temperature indicator. A two dimensional Fourier transform spin-echo imaging sequence was used for data acquisition. The self-diffusion coefficient at room temperature was 1.26 7times; 1O^?3 mm²/sec. Two dimensional self-diffusion images were obtained, and temperature images were calculated. The error in MRI measurements, due to noise and temperature variation, was less than 1°C with 1.5 mm² resolution. The average variation between MRI and thermocouple measurements was < 1.26°C. This new non-invasive technique can be used to study heat transfer and to measure thermal properties of foods.     

High Resolution Magnetic Resonance Imaging Evaluation of Cheese

ABSTRACT: The curd granules/joints structure of the Emmentaler was observed by NMR micro-imaging during the different stages of cheesemaking. During the ripening process, many carbon dioxyde microbubbles have been visualized inside the curd grains, as well as some volumes of fat outside the grains. At the end of the ripening stage, images reveal the final structure does not have a uniform lipid distribution of grains: the density is high at the boundaries and low at the center. Moisture and fat content profile of the rind has been obtained and rind-dependent water and/or fat accumulations are observed. Finally, the contrast difference between curd joints and grains of the studied samples confirms that a higher draining occurs for the joints than for the grains during cheesemaking.     

核磁共振及成像技术在食品工业中的应用

核磁共振技术以快速、无损伤、无侵入检测等优点使其在食品中得到广泛的应用,本文综述了其在食品工业中五大方面的应用,分别为测量食品和生物体系中的含水量、研究食品中水分的分布和水分的流动性、研究果蔬的成熟度和损伤程度、研究食品中的油脂、研究食品的玻璃态转变温度。     

不同添加量的亚硝酸盐和番茄粉对哈尔滨红肠品质特性及氧化程度的影响

研究了在红肠中添加不同含量的亚硝酸盐(150 mg/kg、100 mg/kg和50 mg/kg),同时补充添加不同含量的番茄红素(0%、2%和4%)对其色泽和感官品质的影响,通过pH值、色差、质构特性以及感官评价等得出最佳的添加量为:100mg/kg亚硝酸盐和2%番茄粉素;然后将用该配方生产的红肠与只添加150 mg/kg亚硝酸盐的红肠在4℃贮藏1、7、15、30和45天,结果表明添加番茄红素的红肠氧化程度较低,从成色和抗氧化的角度而言,番茄粉可部分替代亚硝酸盐生产低硝红肠。     

用双向薄层层析检测红曲中的桔霉素

采用双向展开薄层层析检测红曲中的桔霉素，第一相分离红曲中除桔霉素外的其他成分，第二相主要分离桔霉素。第一相展开剂选择氯仿：丙酮＝9：1，第二相展开剂选用苯：乙酸乙酯：甲酸＝6：3：1。结果表明，最小检出量为0.1μg，可检测出红曲中的桔霉素，方法简单易行，容易掌握。（庞晓）     

Imaging of the Fermentation Process of Bread Dough and the Grain Structure of Baked Breads by Magnetic Resonance Imaging

ABSTRACT: Fermentation processes of bread doughs were traced by MRI (magnetic resonance imaging), which suggests that punching and rounding treatment after the first fermentation promotes the development of elasticity and extensibility of gluten fibrils that makes thin grain walls of the pores connecting between adjacent pores with small holes, and a thin smooth crust after baking. While pore generation was small, expansion of the dough was low, gluten networks formed were large and coarse, and gluten fibrils were undeveloped in the frozen dough. Prefermentation could not essentially alleviate the inferior properties of the frozen dough. The grain structures of the bread using frozen dough were characterized by thick network walls without the connection between pores and a thick crust with rough surface.     

Use of Magnetic Resonance Imaging for monitoring Parma dry-cured ham processing

Protocols were developed to apply Magnetic Resonance Imaging (MRI) to the dry-curing of Italian Parma ham. NMR relaxation analyses were performed on dry-cured hams at different processing stages to evaluate the ranges of variation of ¹H relaxation times T₁ and T₂ in representative ham muscle tissues, due to dehydration and salt uptake. MRI maps of the same ham sections were acquired, allowing T₁ and T₂ average values to be computed in selected Regions of Interest (ROI) inside muscle Semimembranosus, Semitendinosus and Biceps femoris. Chloride and moisture were determined by conventional chemical methods on the same ROIs, and MRI T₁ and T₁/T₂ ratio were selected in a model (R² = 0.90, P < 0.05) fitting the salt content of the analysed muscle cores. Short Time Inversion Recovery (STIR) sequences were also applied to green and cured hams, but on fresh samples only, a bright image, displaying a clear separation between lean and fat tissue, was obtained.     

Temperature Mapping of Particles During Aseptic Processing with Magnetic Resonance Imaging

Magnetic Resonance Imaging (MRI) was used to obtain 2-dimensional temperature maps in potatoes undergoing aseptic processing. The change in precession frequency of protons served as the temperature indicator. The larger particles (6.9 and 3.84 cm3) showed a δT (T_surface - T_center) of up to 22±0.4°C 45s after exiting the heat exchanger with the δ (T_outlet - T_inlet) of the carrier fluid in the heat exchanger at 30 to 45°C. No AT was measured between the center and the surface of particles <2.05 cm³ pumped at <22.7 L/min. The average fluid to particle convective heat transfer coefficient (h_fp) for the heat exchanger and holding tube was calculated using a finite element method. The hfp was from 600 to 2500 and >3000 W/m²°C for the large (6.9 cm³ cubes) and smaller particles respectively.     

Soft Flesh Problem in Freshwater Rainbow Trout Investigated by Magnetic Resonance Imaging and Histology

ABSTRACT: To investigate the soft flesh problem in rainbow trout, the dynamics of water in postmortem white muscle were studied by magnetic resonance imaging, histology, and rigor index (θ r ) measurements. At 24-h postmortem, the trout identified as having the soft flesh problem (θ r ≥ 40°) differed from the others (0°≤θ r ≤ 20°) by longer transverse relaxation time (T₂≥ 45 ms) and smaller diffusion anisotropy (DA ≤ 1.3), which proved to be the most relevant nuclear magnetic resonance parameter for an early diagnosis of the soft flesh problem. To interpret these results, we hypothesized an early and exacerbated tenderization phenomenon because of protein denatur-ation, inducing important modifications in fine connections that anchor the 3-dimensional structure of the tissue. The incidence of 3 slaughtering procedures on rigor were tested, and no differences were detected for trout presenting the soft flesh problem.     

番茄制品加工工艺研究进展

就近年来国内外在番茄制品加工工艺方面的研究进行了综述。从提高产品粘稠度、浓缩、浸钙硬化等方面 ,分别介绍了微波加热、高压处理、超滤浓缩、反渗透浓缩、冷冻浓缩以及优化浸钙工艺等技术应用于番茄制品加工的研究近况     

双向薄层层析测定红曲中Monacolin K

采用双向薄层层析法，对红曲产品中Monacolin K的提取方法以及第1展开剂和第2展开剂分别进行了研究。结果表明，采用乙酸乙酯为提取剂，以正己烷：乙酸乙酯：无水乙醚：甲酸(20：1：5：0．5)为第1展开剂，以正己烷：氯仿：无水乙醚(30：1：5)为第2展开剂，红曲产品提取液的：Monacolin K能很好地分离和检测。在此基础上对22个红曲样品进行了分析，结果显示，其中12个样品均高低不一地含Monacolin K。     

Effects of Commercial-scale Pulsed Electric Field Processing on Flavor and Color of Tomato Juice

Effects of commercial‐scale pulsed electric field (PEF) processing on the flavor and color of tomato juice during storage at 4 deg;for 112 d were studied. Tomato juice was prepared by hot break at 88°C for 2 min and then thermally processed at 92° for 90 s or PEF processed at 40 kV/cm for 57 μs. The PEF‐processed tomato juice retained more flavor compounds of trans‐2‐hexenal, 2‐isobutylthiazole, cis‐3‐hexanol than thermally processed or unprocessed control tomato juice (P < 0.05). PEF‐processed juice had significantly lower nonenzymatic browning and higher redness than thermally processed or control juice (P < 0.05). Sensory evaluations indicated that the flavor of PEF‐processed juice was preferred to that of thermally processed juice (P < 0.01).     

NMR和MRI技术对面包和奶酪二元体系在贮藏过程中水分迁移的研究(英文)

采用低场核磁共振成像技术中的spin3D、CPMG等序列对面包和奶酪二元体系进行成像并测定自旋-自旋弛豫时间等参数,并对其在贮藏过程中水分迁移行为及规律进行了研究,为核磁共振技术在食品中的应用打下良好的基础。     

甘蓝红色素的提取与性质研究

本文报道了从红甘蓝中提取花青素类天然食用色素,用大孔吸附树脂精制花青素类天然食用色素的工艺方法,以及甘蓝红色素的理化性质,包括光谱特征和溶液pH及其它理化因素对甘蓝红色素颜色稳定性、呈色强度和色调等的影响。研究表明,与其它来源的花青素一样,随pH增大,最大吸收波长向长波方向移动．Fe~(3 )、抗坏血酸等氧化还原剂加速甘蓝红色素溶液退色,并导致红色组分减少,黄色成分增加,色素溶液的色调由红变黄．     

无花果皮红色素微波提取及其稳定性

利用微波辅助提取无花果皮红色素,采用正交试验方案,对影响色素收率的微波功率、微波时间、微波温度及提取料液比等主要因素进行优化组合试验,并研究无花果皮红色素的稳定性能。结果表明：微波功率400W、微波时间15min、微波温度35℃、料液比1:20(g/mL),无花果皮红色素收率可达89.69%。无花果皮红色素耐热、耐光性强,酸性环境中稳定性较好,常用食品添加剂、氧化剂、还原剂及Na+、K+、Ca2+、Mg2+、Zn2+、Al3+ 等金属离子对该色素无影响,但Fe3+ 对色素有破坏作用。微波辅助能高效提取无花果皮红色素,该色素具有良好稳定性能。     

基于主成分分析验证气调对番茄品质的影响

研究低温环境下不同体积分数的混合气体对番茄感官品质、营养价值的影响。以番茄作为试验研究对象,通过预冷处理,选择开孔率5%的聚乙烯食品包装袋包装,放在温度为8 ℃ CO2体积分数为6%的气调箱内,用N2调节O2体积分数为2%、4%、6%、8%和10%。每隔2 d检测一次番茄品质（质量损失率、色差L*值、TSS、TA及主观评价）之后对6个评价指标进行标准化处理,采用主成分分析法建立得分函数,并用传统感官评价验证得分模型。试验研究表明：4% O2+6% CO2气调环境下番茄各项指标可以维持较好的水平。综合函数评价得分显示在长期气调保鲜过程中,低氧环境有利于番茄保持较高品质。传统感官评价方式与综合函数有一致性。主成分分析法表明4% O2+6% CO2的气调环境下具有较高的得分水平,可以显著维持保鲜过程中番茄的营养价值,并延长气调保鲜周期。     

Hayward kiwifruits and Plant Growth Regulators: Detection and effects in post-harvest studied by Magnetic Resonance Imaging and Scanning Electron Microscopy

We used Magnetic Resonance Imaging spectroscopy to reveal the use of two Plant Growth Regulators (PGRs), i.e. cytokinin and auxin, on Hayward kiwifruits, at any stage of cultivation, and post-harvest ripening and storage. The internal morphology was non-destructively determined in order to depict structural features related to hormones treatments and we found that T₂-weighted MRI images showed different internal tissue organisations depending upon the use and the type of PGR. Transverse relaxation times allowed the recognition of cytokinin-treated samples, whilst image analysis was used to identify auxin-treated kiwifruits. We also exploited the post-harvest conditions, i.e. normal refrigeration and controlled atmosphere, on PGRs treated kiwifruits, and found that auxin shortened the shelf-life, with normal refrigeration exerting a stronger effect. The kiwifruit pulp was also investigated by means of Scanning Electron Microscopy, highlighting significant differences at a cellular level amongst treatments, in terms of pore size and vacuoles number, both probably playing a fundamental role in the evaporation activity.     

UV胶印墨层厚度对印品爆色的影响

为了研究UV胶印墨层厚度对印品爆色的影响,采用银光柱激光转移纸和两种油墨进行实验,对印刷样张进行爆色测试,通过爆色程度量化评分权值,确定了墨层厚度与爆色程度之间的关系。结果表明,墨层厚度及油墨种类对爆色的发生具有重要影响:01号专色油墨随膜层厚度的增加,其爆色程度有先增加后减小的趋势;02号专色油墨随膜层厚度的增加,其爆色程度逐渐增加。