Effects of pH and Sodium Chloride on the Gelling Properties of a Protein Concentrate Obtained from Jumbo Squid Mantle (Dosidicus Gigas)

Jumbo squid (Dosidicus gigas) is an underutilized fishery resource in the Gulf of California. Jumbo squid muscle could potentially be utilized to manufacture protein concentrates to be used as a base for surimi or as a food ingredient. However, the main problem is the low gelling ability of these protein concentrates compared those of with fish species. Consequently, the present study evaluated the effects of pH and the NaCl concentration on the gelling properties of protein concentrates from squid mantle. According to texture profile analysis, improved gelling properties were obtained at pH 6.0 and 1% of NaCl. During the sol-gel transition, decreased surface hydrophobicity that corresponded to an increased intensity of α-helix structures was detected. Moreover, the total sulfhydryl content decreased during gel formation. Viscoelasticity and water holding capacity analyses showed the formation of a more structured gel at pH 7.0. The higher enthalpy and denaturation temperature detected by differential scanning calorimetry at pH 7.0 and 1% NaCl showed that both variables (pH and NaCl concentration) affected the protein structure and conformation. The results demonstrated that varying pHs and NaCl concentrations improved the gelling properties of protein concentrates from squid.     

Optimisation of rancidity stability in long‐chain PUFA concentrates obtained from a rainbow trout (Oncorhynchus mykiss) by‐product

This research was focused on the production of polyunsaturated fatty acid concentrates from a farmed rainbow trout (Oncorhynchus mykiss) by‐product (i.e. belly muscle). The effect of different process variables (urea/fatty acids (FA) contents ratio, crystallisation time and temperature and stirring speed of the urea/FA mixture) on the lipid oxidation development during the urea complexation process was investigated. For this purpose, an experimental design (26 runs) following the response‐surface methodology was developed. As a result, peroxide value and TOTOX index showed to be dependent on the crystallisation time and temperature and the urea/FA ratio, while no influence of the crystallisation stirring speed was detected on both indices; additionally, polyene index was affected by the urea/FA ratio and its interaction with the crystallisation time. An optimised desirability score near 1.0 was attained provided values of 2.8 °C, 3.05 h and 3.57 were applied for crystallisation temperature, crystallisation time and urea/FA ratio, respectively.     

高硫铅锌矿选矿工业试验研究

金东矿业入选原矿为高硫铅锌矿石,且原矿中方铅矿、闪锌矿、磁黄铁矿嵌布关系甚为密切,致使浮选生产指标差。公司为此开展了200 t/d的工业试验研究,试验结果表明,通过优化药剂制度,铅精矿铅品位和回收率分别提高26%及25%,工业试验效果显著。同时经济效益分析表明,本工业试验工艺流程对于类似高硫铅锌矿企业具有一定借鉴价值。     

从铜金精矿中湿法综合回收金银铜硫的工艺研究

对铜金精矿热压酸浸-萃取-电积提取铜、浸铜渣氰化提取金银和煤油溶解提取元素硫的综合回收工艺进行了研究。热压浸铜在110℃和0．45MPa氧分压下操作,有价元素综合回收率高,对环境污染小,是一种清洁的湿法冶金工艺,金、银、铜和硫的回收率分别达到98．3％、82．7％、98．1％和99．2％。     

会理难选铅锌矿石电位调控抑锌浮铅优先浮选新工艺

研究会理锌矿难选铅锌硫化矿电位调控抑锌浮铅优先浮选分离新工艺。用石灰作矿浆pH和电位的调整剂与稳定剂，在矿浆pH为11．88～12．21，矿浆电位在-252～-272mV的条件下，以乙硫氮（N，N-二乙基二硫代氨基甲酸钠）作铅矿物的捕收剂，（ZnSO4＋Na2SO3）组合药剂强化抑制锌矿物等实现铅锌优先浮选分离，取得较好的生产指标。铅精矿Pb品位65．21％。回收率52．30％；锌精矿Zn品位56．48％，回收率84．85％。与原生产工艺相比，铅精矿铅品位与回收率分别提高了13．27％和5．76％，锌精矿锌的品位与回收率分别提高了0．28％和2．28％，选矿药剂成本降低约2元／t-矿，每年可产生经济效益约1234万元。     

氧化铅锌矿利用工艺技术研究进展

本文分析了氧化铅锌矿石的主要特点及对应的选别工艺,综合评述硫化浮选、絮凝浮选、螯合剂浮选、选冶-联合工艺以及原浆浮选技术等处理方法,为氧化铅锌矿的开发利用提供技术参考。氧化铅锌矿的开发利用,应在加强矿石性质研究及浮选理论研究的基础上,注重组合新药剂、联合新工艺、新设备及新技术方法的应用,以期取得更大的进展。     

电位调控浮选在金东高硫铅锌矿的应用

本文介绍了金东高硫铅锌矿电位调控浮选,通过调整剂石灰及组合抑制剂硫酸锌 亚硫酸钠添加至球磨,营造了高碱性及低氧化电位矿浆环境。乙硫氮为捕收剂,铅精矿铅品位及回收率分别提高了26%、25%。并通过分析矿物表面氧化反应及矿浆电位揭示了高硫铅锌矿浮选过程中方铅矿与闪锌矿及黄铁矿的分离机制。     

沱沱河铅锌多金属矿集区地质地球化学特征及找矿潜力

沱沱河铅锌矿集区位于青海省西南部唐古拉山北坡,是全国设立的首批(47片)国家级整装勘查片区之一。该矿集区不仅是青海省铅锌多金属基地的核心区,也是三江北段成矿带最具找矿潜力的矿集区,其中已发现4个铅锌成矿带及40余处铅锌矿床(点),矿集区内不同的地质单元显示了不同富集元素组合,各成矿带均以Pb、Zn为主要成矿元素,但伴生元素差异明显,三叠纪、二叠纪地层是区内比较重要的成矿层位。成矿流体具有低温、中低盐度、中低密度、低压、浅成等特点,具有多期次、多阶段及多来源的富集特点。沱沱河地区矿床规模的大小与异常的规模强度有着密切关联,几乎所有的铅锌矿床及矿(化)点均位于铅锌地球化学省范围内;在总结成矿地质条件的基础上,指出该矿集区有望成为一大型铅锌矿产资源基地,并划分了5处重要的找矿远景区,其中以纳保扎陇-多才玛-布玛浪纳铜铅锌找矿远景区最具寻找大型-超大型矿床的潜力。     

Pekmez: A Traditional Concentrated Fruit Product

Pekmez is a traditional Turkish food made by using different fruits such as grape, mulberry, fig, apple, and sugar beet. There are two different kinds of pekmez, either liquid pekmez or solid pekmez, produced in Turkey. The stages for processing liquid pekmez for all fruits, except mulberry, include washing, sorting, crushing, pressing, and boiling. By using liquid pekmez, and solidifying and bleaching its agents solid pekmez is produced. Pekmez is a healthful food due to its nutritional content and is used as a main source of energy based on its chemical composition. The carbohydrates in pekmez are generally in the form of natural sugars like glucose and fructose, which is nutritionally important for babies, children, sportsmen, and active workers. Pekmez production and its chemical composition should be adapted to the modern food technology and food safety requirements; at the same time, this adaptation should conserve the authentic properties of the product.     

Ability of flaxseed and soybean protein concentrates to stabilize oil-in-water emulsions

The ability of flaxseed protein concentrate (FPC) to stabilize soybean oil-in-water emulsion was compared with that of soybean protein concentrate (SPC). The stability of emulsions increased with increase in protein concentration. The FPC-stabilized emulsions had smaller droplet size and higher surface charge, but worse stability at the same protein concentration compared to SPC-stabilized emulsions. Oil-in-water emulsions stabilized by both proteins were diluted and compared at different pH values (3–7), ionic strength (0–200 mM NaCl) and thermal treatment regimes (25–95 °C for 20 min). Considerable emulsion droplet flocculation occurred around iso-electric point of both proteins: FPC (pH 4.2) and SPC (pH 4.5). FPC and SPC-stabilized emulsions remained relatively stable against droplet aggregation and creaming at NaCl concentration below 100 and 50 mM, respectively. The emulsions stabilized by both proteins were fairly stable within these thermal processing regimes. FPC appears to be less effective as an emulsifier compared to SPC due to its lower emulsion viscosity. Hence, FPC could be more effective in emulsions that are fairly viscous.