The objective of the present investigation was the characterisation of yellow pea (Pisum sativum L ) fractions obtained on a commercial scale by air classijication of the milled peas. Some analytical aspects of the process were investigated including particle size distribution of fractions and their functional properties.
The yellow field pea (Pisum sativum L var Auralia) cultivated in Hungary, its flour and fractions thereof were obtained from Torokszentmiklos Mills, Hungary. Dehulled peas were passed through an Alpine Pin Mill model 630C and fractionated using an Alpine Air Classifier Type 132 M P (both from Alpine AG, Augsburg, FRG). The samples produced were designated pea flour I, fine fraction I and coarse fraction I. Pea flour I was remilled/air-classified producing pea flour 11, fine fraction I1 and coarse fraction 11.
These six pea flour samples were investigated. Particle size distributions of fractions (specific particle diameters in pm) were determined with a CILAS 715 Laser granulometer (CILAS, Marcoussis, France). Crude protein (N x 6.25) content was measured by the Kjeldahl procedure using automatic Kjell-Foss equipment (A/S N FOSS Electric, Hiller~d, Denmark).
Water absorption capacity was measured by the centrifuge method of Sosulski (1962) and fat absorption capacity by the centrifuge procedure of Lin et a1 (1974). Emulsifying activity and emulsion stability were measured by the method of Yasumatsu et a1 (1972), emulsifying capacity by the method of Orrnai-Cserhalmi and Kucsora (1987) and nitrogen solubility index (NSI) by the method of Smith and Circle (1972).
Particle size distribution for pin-milled pea flour I and its fractions after one pass through the mill (fine I and coarse I) is illustrated in Fig 1 . Differences can be seen between the particle size distribution of pea flour and its fine and coarse fractions.