Starch classification

A separator centrifuge is a disk-type, continuous centrifuge. The starch is concentrated in the separator due to centrifugal force. Starch granules with the highest density 

Fiber extraction-------Starch classification-------Fiber classification------Side line sieving 

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CAS 9005-25-8 EINECS/ELINCS 232-686-4 Synonyms / rrowroot starch Com starch Potato starch Rice starch Sago starch Sorghum gum a-Starch Starch, converted Starch, com Starch dust Tapioca starch Wheat starch ClassiFication Carbohydrate polymer... 

INS1420 E1420 Synonyms Acetylated starch Classification Food starch modified Definition Starch esterified with acetic anhydride or vinyl acetate... 

Leszczyhski W. Resistant starch—classification, structure, production. Polish J Food Nutr Sci 2004 13/54 (l) 37-50. 

Synonyms Phosphate crosslinked starch Classification Food starch modified... 

Fine grinding and air classification make possible the production of some cake flour from hard wheat and some bread flour or high-protein fractions from soft wheat. AppHcation of the process theoretically frees the miller from dependence on different wheats, either hard or soft, that change each crop year. The problem is how to market the larger volume of low protein or starch fractions at prices adequate to justify the installation and operation of the special equipment (46). 

Ferguson, KA, Starch-Gel Electrophoresis— Application to the Classification of Pituitary Proteins and Polypeptides, Metabohsm 13, 985, 1964. 

Recently, two novel procedures have been described for the isolation of PHA granules based on air classification [81] or centrifugal fractionation [82] (Fig. 8). These two processes are related to the well established wet and dry milling methods used in the corn industry for the fractionation of corn seeds into endosperm, germ, and hull and for the isolation of starch grains [83]. 

Starch content of field peas (Pisum sativum L., cv. Trapper) ranges from 43.7 to 48% and, after being subjected to pin milling and air classification, produces a flour containing 78% starch (9,12,13). 

The composition of protein and starch fractions produced from pin milling and air classification are related to a number of variables variability in composition of field pea cultivars, number of passes through pin mill and air classifier, vane settings and protein content of peas, and seed moisture (5,9,23,31). 

Protein content of field peas is negatively correlated with lipid, cell wall material (CWM), sugar, and ash content and positively correlated with starch separation efficiency and protein separation efficiency in air classification of pea flour. The lower separation efficiency of low protein peas may be due to their high lipid and CWM content which makes disintegration of seeds and separation into protein and starch particles by pin milling difficult. It is suggested that peas with a specific protein content should be used in order to control the protein and starch fraction contents (18). 

Amino Acid Content. Amino acid content of field pea products is related to protein level, method of processing, and fraction (starch or protein). The protein fraction contains fewer acidic (glu, asp) amino acids than the starch fraction and more basic (lys, his, arg) amino acids than the starch fraction. Also, there are more aromatic (tyr, phe) amino acids, leu, iso, ser, val, and pro in the protein fraction than in the starch fraction (5). An amino acid profile of pea protein concentrate shows relatively high lysine content (7.77 g aa/16 g N) but low sulfur amino acids (methionine and cystine) (1.08-2.4 g aa/16 g N). Therefore, it is recommended that air classification or ultrafiltration be used because acid precipitation results in a whey fraction which contains high levels of sulfur amino acids (12,23). Also, drum drying sodium proteinates decreases lysine content due to the Maillard reaction (33). 

The objectives of the present study were to compare the processes of protein and starch concentration by dry air classification and wet alkali extraction of protein and starch from field pea and fababean. The yields, composition and functionality of the crude and refined products were compared. 

Figure 1. Flow diagram for pin milling and air classification of field pea and fababean into protein and starch fractions.

Functional Properties. The pH s of the flours and products obtained by air classification varied between 6.5-6.7 (Table III), which was typical of legume flours (1.3). The proteinates were near oH 7 because of the neutralization orocedure after isoelectric orecioita-tion while the refined starch and fiber were still alkaline in pH despite several washings with distilled water. In a previous study, adjustment of the pH of lupine flour was shown to have a significant influence on functional properties (1) but pH was not adjusted in the present investigation. 

Czaja, A. T. (1978). Structure of starch grains and the classification of vascular plant families. Taxon T1,463 70. 

Englyst,H. N., Kingman, S. M., Cummings, J. H. (1992). Classification and measurement of nutritionally important starch fractions. European Journal of Clinical Nutrition, 46, S33-S50. 

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