Detection of pressed hazelnut oil in admixtures with virgin olive oil by analysis of polar components

Analysis of the polar fraction from virgin olive oil and pressed hazelnut oil by high-performance liquid chromatography showed marked differences in the chromatograms of the polar components in the two oils. Six commercial samples of pressed hazelnut oil and 12 samples of virgin olive oil (or blended olive oil including virgin olive oil) were analyzed. The phenolic content of the pressed hazelnut oil samples was 161±6 mg·kg⁻¹. Inspection of the chromatograms showed that the pressed hazelnut oil extracts contained a component that eluted in a region of the chromatogram that was clear in the olive oil samples, and consequently this component could be used to detect adulteration of virgin olive oil by pressed hazelnut oil. The component had a relative retention time of 0.9 relative to 4-hydroxybenzoic acid added to the oil as an internal standard. The ultraviolet spectrum of the component showed a maximum at 293.8 nm, but the component could not be identified. Analysis of blends of oils showed that adulteration of virgin olive oil by commercial pressed hazelnut oil could be detected at a level of about 2.5%.     

Machines for olive paste preparation producing quality virgin olive oil

Polyphenolic substances enhance the resistance to oxidation of virgin olive oils, but an excess of polyphenols determines a marked bitter, somewhat tannic taste of the oil, similar to the taste of unripe olives. Tests have been carried out on drupes of different cultivars in industrial productions to evaluate the effect of the machines used to prepare olive pastes on the contents of polyphenols in the oils. Notably greater amounts of polyphenols were found in the oils extracted from hammer-crushed pastes than in the oils extracted from milled pastes. The kneading process which follows, especially if it is long, often reduces the amounts of total polyphenols. Therefore, in order to obtain the best organoleptic and chemical quality in extra virgin olive oils, two systems are suggested for the processing procedures. For olives of certain cultivars (Coratina) and for not-blackened or slightly blackened drupes yielding oils with a very high content of total polyphenols, it is most expedient to use the stone-mill together with a kneader system. But it is more suitable to utilize the hammercrusher together with a kneader system in processing olives (such as the Ogiiarola Salentina or Leccino cultivars) yielding normally “sweet” oils with a low content of total polyphenols.     

美国陶瓷砖标准解析

主要介绍了陶瓷砖美国国家标准ANSIA137.1-08在分类、技术要求、试验方法以及包装标识等方面的主要要求,分析了美国标准与我国标准的主要差异性,指出对美出口产品应注意的一些问题。     

Leaf filter for foots removal from crude oil reduces labor and eliminates filter cloth and paper

A consideration of the economics of installing a leaf type of filter for crude oil in a new mill or as a replacement for existing filtration equipment must take into account the following advantages which a pressure leaf filter offers:

1. Entire filter operation can be handled by a single operator with no assistance required for cleaning;
2. complete elimination of cost of filter cloths and Viskon papers normally used to dress filter presses;
3. elimination of storage, handling, cutting, etc., of cloths and papers;
4. completely enclosed, leak-free filter installation;
5. drier filter cakes with less air-blowing time and lower air consumption;
6. a permanent filter medium (woven wire cloth) of stainless steel which cannot corrode, or rupture during operation, thereby causing passage of solids into filtered oil;
7. high degree of solids removal, resulting in low refining losses;
8. a cleaner filter station;
9. less strenuous labor; and
10. economical construction in carbon steel.