Supercritical CO2 extraction of oilseeds: review of kinetic and equilibrium models

Mass transfer models on supercritical carbon dioxide (SC-CO2) extraction of vegetable oils are reviewed, that may facilitate the scale-up of laboratory data for industrial design purposes. Reviewed mechanisms of oil transport within the solid matrix include the desorption from the solid, the formation of a shrinking core of condensed oil in a non-adsorbing porous matrix, and diffusion in a homogenous medium. Analyzed simplificat ions of a general mass transfer model include external control of mass transfer rates, internal control of mass transfer rates, consideration of a linear driving force, and steady state approximations, among others. More complex two-stage models, and critical comparisons of some of the proposed models are also included. Trends for the external mass transfer coefficient and effective diffusivity in the solid matrix from studies on SC-CO2 extraction of oil from vegetable substrates are thoroughly discussed and contrasted with those obtained using simpler model systems. The possible effect of the axial dispersion on the rate of extraction is also discussed. Finally, the high-pressure vegetable oil-CO2 phase equilibrium is discussed in connection with its influence on the mass transfer process. Special emphasis is given to the role of the solid matrix on high-pressure phase equilibrium.     

油用萝卜的研究现状及展望

为带动我国油用萝卜产业的快速发展,促进以食用油为主,多产业(中药、芽苗、绿肥)协同发展局面的形成,系统概述了有关油用萝卜育种、栽培及管理,萝卜籽组成成分及功能,萝卜籽油加工技术方面的研究进展,论述了我国油用萝卜发展面临的问题,提出了相关建议,并展望未来油用萝卜产业的发展趋势及方向。油用萝卜品种类型丰富,适应性广,是一种具有推广应用潜力的新型油料作物品种。     

Genome Mining and Evaluation of the Biocontrol Potential of Pseudomonas fluorescens BRZ63, a New Endophyte of Oilseed Rape (Brassica napus L.) against Fungal Pathogens

Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of Pseudomonas fluorescens BRZ63, a new endophyte of oilseed rape (Brassica napus L.) against Rhizoctonia solani W70, Colletotrichum dematium K, Sclerotinia sclerotiorum K2291, and Fusarium avenaceum. In addition, features crucial for biocontrol, plant growth promotion, and colonization were assessed and linked with the genome sequences. The in vitro tests showed that BRZ63 significantly inhibited the mycelium growth of all tested pathogens and stimulated germination and growth of oilseed rape seedlings treated with fungal pathogens. The BRZ63 strain can benefit plants by producing biosurfactants, siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and ammonia as well as phosphate solubilization. The abilities of exopolysaccharide production, autoaggregation, and biofilm formation additionally underline its potential to plant colonization and hence biocontrol. The effective colonization properties of the BRZ63 strain were confirmed by microscopy observations of EGFP-expressing cells colonizing the root surface and epidermal cells of Arabidopsis thaliana Col-0. Genome mining identified many genes related to the biocontrol process, such as transporters, siderophores, and other secondary metabolites. All analyses revealed that the BRZ63 strain is an excellent endophytic candidate for biocontrol of various plant pathogens and plant growth promotion.     

Supercritical CO2 oilseed extraction in multi-vessel plants. 2. Effect of number and geometry of extractors on production cost

The objective of this work was to study production costs for the supercritical CO₂ extraction of a pre-pressed oilseed (packed bed with 2-mm particles) in a 2-m³ industrial multi-vessel plant operating at 40 °C and 30 MPa, using a fully predictive mass transfer model to simulate the process. We modified the inner diameter (47.3 ≤ D ≤ 65.6 cm) and number (n = 2, 3, or 4) of extraction vessels, and the mass flow rate of CO₂ (Q = 3000 or 6000 kg/h), thus changing the aspect ratio of the extraction vessels (3 ≤ L/D ≤ 8), and superficial velocity (2.71 ≤ U ≤ 10.8 mm/s) and specific mass flow rate (6 ≤ q ≤ 24 kg/h per kg substrate) of CO₂. Production cost decreased when increasing the mass flow rate of CO₂ or the number of extraction vessels (or when increasing q). Production cost did not depend on the geometry of extraction vessel for a constant specific mass flow rate of CO₂, but it decreased with a decreasing of the L/D ratio of the vessel for a constant superficial velocity of CO₂. For any given plant, the contribution of fixed cost items (capital, labor) to the production cost increased with extraction time, unlike that of variable cost items (substrate, CO₂, energy), which decreased. Thus, there was an optimal extraction time that minimized production cost for each plant. This work proposes an expression for capital cost of an industrial multi-vessel plant as a function of the mass flow rate of CO₂ (which defines the cost of the solvent cycle of the plant), and the volume of the extraction vessels (which together with number of extraction vessels define the cost of extraction section of the plant), with a scaling factor of 0.48 for both items. Under optimal conditions, capital cost represented 30–40% of the production cost, but uncertainties in capital cost estimates (about ±50% using the proposed expression) may largely affect these estimates. The lowest production cost estimated in this work was USD 7.8/kg oil for the extraction of prepressed oilseed in a four-vessel plant using 6000 kg/h of CO₂. The mass flow rate of CO₂ and number of extraction vessels also affected annual productivity that was about 360 ton oil for the same plant operating 7200 h per year. Oil yields were above 90% for both three- and four-vessel plants.     

Temperature effects on fatty acid composition during development of low-linolenic oilseed rape (Brassica napus L.)

The influence of temperature during seed development on the fatty acid composition of oilseed rape (Brassica napus L.) was studied in one low-linolenic and one conventional canola cultivar. The cultivar Regent produces seed oil with ∼20% linoleic acid (C18:2) and ∼8% linolenic acid (C18:3), whereas Stellar is relatively high in C18:2 (∼25%) and low in C18:3 (∼2.5%). Both cultivars were grown in the field, and the fatty acid compositions of the seed oils were monitored throughout the period of seed development. In the field, the content of saturated (C16:0+C18:0) and monounsaturated (C18:1) fatty acids in the seed oil increased when seed developed under high temperatures. C18:3 levels were higher in seed harvested at sites with lower average daily temperatures. The low C18:3 trait of the cultivar Stellar was relatively stable over environments. Both temperature and duration of exposure to the temperature during seed development affected the fatty acid composition of the seed in a controlled environment study. Plants subjected to a high-temperature treatment (30/25°C day/night) for 40 d produced seed with the lowest C18:3 content and the highest levels of C16:0+C18:0 and C18:1. This was observed in both cultivars.     

Comparison of two standard methods for determination of free fatty acids content in oils extracted from oilseeds and vegetable oils

Two standard titrimetric procedures for determination of free fatty acids in vegetable oils and in oils extracted from oilseeds were examined using rapeseed oil, illipe nuts and fat, and groundnuts and groundnut oil as test materials. Both procedures involve dissolution of the fat in an organic solvent and titration with standard alkali solution using phenolphthalein as indicator. Results obtained using each of the two methods agree closely in most cases and certainly for commercial contractual purposes the two methods are interchangeable. Suggestions are made for modification of these methods particularly in regard to solvents and allowed variation in analysis results.     

Immunological investigation of lipases in germinating oilseed rape,Brassica napus

An anti-lipase antibody has been used to investigate the lipases of cotyledons from germinating seedlings of oilseed rape, Brassica napusL, var Mikado. Immunological and enzymic assays revealed that lipases were confined to germinating seeds and were absent from other tissues, such as developing seeds, leaves, roots and flowers. The antibody totally inhibited microsomal lipase activity at a ratio of 12 μg IgG protein: 10 μg microsomal protein. It was shown by immunoblotting of microsomal, oil-body and total cotyledon proteins separated by gel electrophoresis that, in each case, the antibody specifically bound to a single polypeptide. This polypeptide had an electrophoretic mobility consistent with a molecular weight of 56 kDa. The appearance and subsequent decline of the 56 kDa polypeptide during the first 10 days of germination closely followed that of the lipase activity, both in microsomal protein and total cotyledon protein fractions. An ELISA for the lipase demonstrated that the amount of immunoreactive microsomal lipase present at each stage of germination was proportional to its enzymic activity. The enzymic and immunological activities of the microsomal lipase each exhibited buoyant densities of 1.087 g ml^?1 on sucrose density gradients. Lipases were present in only very small amounts in dry seeds and were synthesised de novo after 2–3 days of germination.     

油料冷榨的概念和应用范围

介绍了国外油料冷榨技术的发展缘由和现状,以及油料冷榨技术所具有的优缺点和应达到的技术指标,并对适合于中国油料冷榨技术的应用范围进行了叙述.     

基于ARIMA模型的中国木本油料未来供给战略研究

粮油安全事关国计民生,大力发展木本油料产业、提升木本油总供给是提高我国食用油自给率、保障国家粮油安全的最佳选择。以油茶籽、核桃、油橄榄3种主要木本油料为例,利用三者2000—2019年的产量数据及前人研究进行测算,得出油茶籽油、核桃油、橄榄油3种主要木本油的同期供给量,建立ARIMA模型对我国这3种主要木本油料及木本油的未来供给进行预测。结合预测结果和国家既定发展目标,从我国木本油料产业存在缺乏优秀人才,科技支撑不足,产业结构不合理,生产加工能力弱,资金投入有限,宣传力度不足等主要问题出发,提出强化科技支撑,做好科学规划,加大政策支持,增加宣传力度等建议,以期为我国政府进行科学宏观调控、推动木本油料产业高质量发展提供数据参考与技术支持。     

油菜秸秆基料对4种常见食用菌产量和活性成分的影响

为了评价油菜秸秆栽培食用菌的可行性,分别以油菜秸秆、油菜秸秆和棉籽壳比例4:6(w/w)、棉籽壳为基料栽培4种常见食用菌,分析油菜秸秆对食用菌的鲜重、生长期、多糖含量、葡糖糖醛酸含量和粗多糖分子量分布的影响。结果显示:当基料中油菜秸秆和棉籽壳比例4:6时,香菇、平菇和黑木耳的鲜重最高,分别为480.18、485.26和430.16 g;同时其生长期最短,分别为24.64、19.73和18.64 d,这表明在传统棉籽壳基料中适当增加油菜秸秆有利于提高该3种食用菌产量,相对于单独棉籽壳基料,香菇、平菇和黑木耳的多糖含量显著性提高了11.09%、24.86%和14.26%(P<0.05),葡萄糖醛酸含量也均有所提高,特别是在香菇中存在显著性差异(P<0.05)且其粗多糖分子量分布无明显差异,这表明油菜秸秆的适当添加也有利于提高该3种食用菌活性成分。但在金针菇栽培中,油菜秸秆的添加使其产量和活性成分均显著性地降低(P<0.05),说明油菜秸秆仅在部分食用菌的栽培中具有较高的应用价值。