Plant proteins are normally soluble in weak alkali solution. However, if these proteins are heat-treated, as normally occurs during processing of many ingredients, the solubility of protein will decline. Dale and co-workers at Georgia have developed a fairly rapid test which seems to give a reasonable estimate of protein solubility and hence protein quality in soybean meal. The assay involves adding just 1.5 g of soybean meal to 75 ml of 0.2% potassium hydrox ide solution, and stirring for 20 minutes. Soluble proteins will be in the liquid phase and so all or a portion of the centrifuged liquid is assayed for crude protein, and protein content relative to the original 1.5 g sample calculated accordingly. By knowing the crude protein content of the original sample of soybean meal, percentage solubility can easily be calculated. Typical results, as shown by Dale and Araba are given in Table 2.19. As heating time is increased, there is a decrease in protein solubility. Values of 75-80% solubility seem to be ideal, with higher values suggesting under-heating, and lower values over-heating of the protein. A variation of this test is to assess protein solubility in water. Sometimes termed Protein Solubility Index, the results of water solubility are said to be more highly correlated with feeding value than are estimates of urease index or protein solubility in KOH.
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The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.