Seed Pressing

Fisher s engineering innovations include the following devices (1) a building-block press (2) an oil-seed press and (3) a micro-irrigation pump. Let us look briefly at each. 

S. Hallin, Building with hemp. Editors Seed Press, 2005. 

Mechanical Pressing. Historically, the first large commercial production of oils from seeds and nuts was carried out using labor-intensive hydraulic presses. These were gradually replaced by more efficient mechanical and screw presses. Solvent extraction was developed for extraction of seeds having low oil content. For seeds and nuts having higher oil content, a combination of a screw press followed by solvent extraction is a common commercial practice (prepress—solvent extraction). 

The composition of a number of fmit juices and juice drinks is given in Table 1. Figure 1 describes many of the steps in the production of fmit juices. The processing of citms and deciduous fmit into juice is discussed separately. Citms have a thick, relatively tough peel that must be kept separate from the juice during extraction. Deciduous fmit are cmshed whole and the juice is then separated from the pulp, peel, and seeds, usually in a pressing operation. 

K. R. Kaufman, in E. D. Shult2 and R. P. Morgan, eds.. Fuels and Chemicals from Oil Seeds Technology andPoliy Options, Westview Press, Boulder, Colo., 1982, pp. 143-174. 

N. Torimoto,/. Chem. Educ. 64, 332 (1987) K. Honda, personal communication, 1992 D. Miller, Indigo, from Seeds to Dye, 3rd ed.. Indigo Press, Aptos, Calif., 1984. 

A. M. Altschul and H. L. Wilcke, eds., NeiP Protein Foods, Vol. 5, Seed Storage Proteins, Academic Press, Inc., New York, 1985, 471 pp. 

In the past, expression presses were used in many processes for extracting oil and juice, generally from seeds and fruits such as olives. Batch presses were typically used in these apphcations, and hand unloading of the pressed cake was often required. Batch presses that require hand unloading or extensive cleaning between pressings are rarely used now descriptions of various types are presented in earlier editions of this handbook. This section, therefore, describes mainly continuous presses. 

Screw presses were traditionally used for seeds and fruits that had to be mechanically ruptured to release the liquid in the seeds or cells... 

Sauer, J. D. 1988. Plant Migration. The Dynamics of Geographic Patterning in Seed Plant Species. University of California Press, Berkeley, CA. 

J.D. Bewley, M. Black, Seeds Physiology of Development and Germination, Plenum Press, New York and London, 1994. 

The pure product is produced by dissolving the gum from the seeds in hot water. Diatomaceous earth filtration is then used to purify the solution. As the gum is less soluble in alcoholic than aqueous solutions it is precipitated by adding propan-2-ol. The pressed filter cake is then washed in pure alcohol to dehydrate it. The alcohol is then recovered by pressing again. The pressed product is then milled to the required final size. 

Daussant, J. Mosse J. Vaughan, J. "Seed Proteins". Academic Press, Inc., London, 1983. 

Typically, full-fat flours are made by hammer milling the seed to pass through 80-mesh or smaller size screens. However, grinding of oilseeds containing over 25% oil results in sticky flours. Thus, partially-defatted peanut and sunflower seed flours are made by first screw pressing the seed to reduce the oil to 6-18% fat content. 

Practically all the coffee planted commercially comes from seed, except in the rather limited Robusta-growing region of Java where grafted plants are used. Coffee seeds are planted in seedbeds and are treated in about the same way all over the tropics. The mature and apparently healthy fruits are selected and the seeds are pressed out, washed and dried in the shade, and planted rather soon, because coffee seed viability is lost within a comparatively short while. Handled in this manner, the chances are lessened that coffee diseases will be carried by seeds. However, it has been proved experimentally that infected plants can be produced from seeds contaminated with both the coffee Colletotrichum and the coffee Cercospora from either field material or artificial inoculation. This contamination is probably not uncommon in plantation practice and thus far it is not of extreme importance. The Hemileia rust is probably not carried on the seed (93). The American leaf spot is not carried on seed (97). 

Species of Datura, Hyoscyamus and other tropane-containing genera are of more risk to humans than animals. These plants and their seeds have been used for religious or social functions with ritualistic emphasis. Numerous cases of bizarre and often aggressive behavior have been reported in people using seeds or teas from these plants (Burrows and Tyrl, 2002). As recently as October of 2003, a report appeared at CNN.com of four teenagers who ate Jimson weed seeds. All hallucinated and had to be hospitalized. Two were sedated and placed on life-support to prevent danger to themselves and others. The same press release reported that Centers for Disease Control and Prevention... 

Once the area is sown, press down gently to ensure that the seeds are in contact with the soil. 

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