Investigation of activated Al-pillared clay efficiency in vegetable oil purification

This paper represents a contribution to the applicability of natural clays and their derivates as adsorbents in the process of purification of vegetable oil. Investigation of textural properties of raw and purified clay samples reveals that during acid activation and Al-pillaring, BET and micropore surface area increases significantly. However, bleaching capacity of clay and its derivates is not determined by using sample surface area, but rather sample total pore volume. Surface area, especially micropore surface area contributes to removal of smaller molecules. This was confirmed by successful elimination of moisture and volatile materials by samples with an appropriate micropore structure. Used samples of clay and its derivates do not significantly influence acid and peroxide values of raw sunflower oil during its treatment

Physical and chemical characteristics of stearin and olein obtained by dry fractionation of milk fat

Frakciona kristalizacija ja termomehanički postupak koji omogućuje razdvajanje triglicerida po stupnju nezasićenosti. Ovaj tehnološki postupak u industriji ulja koristi se za dobijanje raznih tipova namjenskih masti. U radu je izvršeno frakcioniranje jednog uzorka mliječne masti iz otopine tzv. direktnim postupkom. Frakciona kristalizacija rađena je u vertikalnom laboratorijskom kristalizotoru sporohodnom miješalicom (16 o/min). Rastopljena mliječna mast temperature 60 °C je kontrolirano i polagano hlađena po određenom temperaturno-vremenskom, režimu od 24, 25 i 26 °C. U toku procesa frakcioniranja iskristalizirana frakcija triglicerida s višom točkom topljenja (stearin) odvajana je od tekuće frakcije (oleina) filtracijom na vakuumu. Kristalizacija, procjena kvalitete i mogućnosti primjene dobijenih frakcija vršene su određivanjem točke kapanja, točke očvršćavanja i sadržajem čvrstih triglicerida.Fractional crystalization is known as thermo-mechanical procedure that enables separation of triglicerides according to the degree of unsaturation. This technological procedure is used in oil industry for the production of various types of special fats. This paper reviews the investigations on the application of the method of dry fractionation. Fractional crystalization has been carried out in vertical laboratory crystalizer with slow rotational mixer (16 r.p.m.). Melted milk fat, at the temperature od 60 °C has been slowly and under controlled conditions cooled according to predetermined temperature and time regimes up to 24, 25 and 26 °C. In the course of the procedure of fractionation, the obtained crystalized fraction of triglicerides with a higher melting point (stearin) has been separated from liquid phase (olein) by vacuum filtration. Characterization, quality evaluation and possibilites for application, for the obtained fractions, have been carried out by the determination of dropping point, solidification point and solid fat index

Fundamentals of Multi-User MIMO Communications

In recent years, the remarkable promise of multiple-antenna techniques has motivated an intense research activity devoted to characterizing the theoretical and practical issues associated with multiple-input multiple-output wireless channels. This activity was first focused primarily on single-user communications but more recently there has been extensive work on multi-user settings. The aim of this chapter is to provide an overview of the fundamental information-theoretic results and practical implementation issues of multi-user multiple-antenna networks operating under various conditions of channel state information

Essential fatty acids, nutritive value and oxidative stability of cold pressed hempseed ( Cannabis sativa L.) oil from different varieties

The fatty acid composition, nutritive value and oxidative stability of cold pressed oils, obtained from seven different hemp cultivars, were investigated. The results show that the content of gamma-linolenic acid in the oil depends on the cultivar, ranging from 0.80 to 2.46%. The ratio between essential omega-6 and omega-3 fatty acids in the oil was 3.5:1 to 4.2:1, satisfying the demands of modern healthy nutrition regarding lipids. Due to high content of polyunsaturated fatty acids, the oxidative stability of cold pressed hemp oil is poor. The induction period at 100 °C, determined by accelerated oxidative method — Rancimat test, was 6.4 to 7.6 h

Oxidative stability and tocopherol content of refined sunflower oil during long-term storage in different commercial packagings

The study was undertaken to monitor the changes in oxidative stability and α-tocopherol content of refined sunflower oil during 12 months of storage at room temperature in different commercial packagings: Tetra brick, polyethylene terephthalate (PET) bottles and polyethylene (PE) canisters. The results showed significant influence of packaging type on the oxidative stability of oil. The largest changes were determined in oil packed in PE canisters (volume 5 l), where the peroxide values (PV) after 12 months were 9.34 and 10.46 mmol kg−1, while the lowest increase in PV were 1.05 and 1.67 mmol kg−1 in Tetra brick packaging. The highest increase in specific absorbances was also noticed for oil packed in PE canister. It came to loss of tocopherol during storage in accordance with the degree of oil oxidation. In oil packed in Tetra brick 6.52 and 8.14% losses of tocopherol (compared to the initial value) were found, while the losses in canister were found to be 14.18 and 17.88%. The results of Schaal-oven test also indicated decrease of oxidative stability during storage in accordance with protective properties of packagings and packing conditions

Influence of fatty acid composition of sunflower kernel on quality and shelf-life of cookies

Sunflower kernel is a rich source of nutritively valuable components like proteins, essential fatty and amino acids, vitamins and mineral matters and as such, is a convenient raw material for the production of enriched cookies, biscuits, crackers as functional food. The influence of high-oleic type sunflower kernel on quality and stability of cookies was investigated, compared to products with standard confectionary sunflower kernel, with dominating polyunsaturated linoleic acid. The optimal keeping time of cookies with standard confectionary sunflower kernel is 4 months, and of cookies with high-oleic sunflower kernel is significantly longer than 5 months

Surface Patterning Increases Fluid Sorption Efficiency in Porous Reactive Coatings: A Model for Optimised Surface-Flow Filtration

A novel surface-flow filter has been designed to take advantage of a combination of both diffusion and lateral flow permeation, since active coatings, even if porous, tend to be far less permeable than through-flow constructs. The formation of a continuous coating layer virtually excludes any fluid transport into the coating other than by planar diffusion for gases or capillarity for liquids. This study considers the additional potential advantage of creating a pixelated/patterned coating, applied using a pin coater to form printed dots onto a highly permeable cellulose fibrous paper-like substrate. The coating-fine particulate calcium carbonate combined with micro-nanofibrillated cellulose as binder and humectant-reacts on exposure to NO2 gas to form calcium nitrate. Experimental results show an effective doubling of nitrate-forming efficiency using pixelated coating compared with a reference continuous layer coating. To establish an understanding of the comparative mechanisms of gas-coating contact, computational fluid dynamic modelling is used to generate surface pressure profiles combined with a pore network model of the coating to estimate theoretical fluid permeability and gas diffusion coefficients. Although pressure-driven permeation was calculated to be approximately two orders of magnitude less than the diffusive flow, it is concluded that patterned aerofoil pressure differential effects can reduce the impact of surface stagnant layering and so aid fluid transfer, boosting the diffusive transport, which in turn delivers greater contact efficiency based on the increased accessibility to the active coating