Eur Food Res Technol (2003) 217:486–491 DOI 10.1007/s00217-003-0775-3 ORIGINAL PAPER K. O. Falade · K. I. Adeyanju · P. I. Uzo-Peters Foam-mat drying of cowpea (Vigna unguiculata) using glyceryl monostearate and egg albumin as foaming agents Received: 31 January 2003 / Revised: 9 July 2003 / Published online: 30 October 2003  Springer-Verlag 2003 Abstract Foam-mat drying of cowpea using glyceryl monostearate (GMS) and egg albumin (EG) as foaming agents was investigated. GMS and EG were incorporated into cowpea paste (22%, 25% and 28% total solids) at 2.5, 5.0, 7.5, 10.0, 12.5 and 15% (w/w), and whipped for 3, 6, 9, 12, 15, 18 and 21 min, maintaining 15, 25 and 35 C foaming temperatures. Foam density was measured and expressed in g/cm 3 . Cowpea foams were dried at 60 C (Twb, wet bulb temperature 35 C) for 48 min. Sensory attributes of akara produced from fresh and reconstituted pastes were evaluated. Generally, foam density decreased with increased concentrations of GMS and EG in cowpea paste. Foam density decreased with decrease in total solids of cowpea paste. Minimum foam densities were obtained in cowpea foams with GMS and EG after 9 and 21 min of whipping, respectively. EG-stabilized foams were unstable for drying. Sensory evaluation showed no significant differ- ence (P>0.05, 0.01) in the quality attributes of akara produced from fresh and reconstituted GMS-stabilized cowpea powders. Introduction Cowpea (Vigna ungniculata) is a primary food legume in West Africa, with more than 90% of the world crop being produced in that region of the world [1].Cowpea is an important item in the diet of most Africans and Nigerians in particular [2].Cowpeas are rich source of dietary protein [3, 4, 5] and are consumed in different forms. In addition, a varied and sophisticated African cuisine exists that is based on the use of cowpea paste [6]. The paste forms the basis of several popular food item such as moinmoin and akara, which are prepared by steaming and deep-fat frying, respectively. Traditional processing of cowpea in the preparation of certain cowpea dishes is cumbersome, tedious and time- consuming. This has limited the consumption of such dishes. Although cowpea flour simplifies food preparation for the consumer by eliminating the need for dehulling and grinding, problems with its use have emerged [1]. Major complaints noted in the use of commercial cowpea flour by Nigeria housewives were poor water absorption of the flour and production of akara balls that were heavy, lacked crispness and lacked the cowpea flavour normally associated with akara made from fresh paste [6]. Cowpea flour can be produced by other methods, which would yield better qualities and reconstitution properties. Thus, foam-mat drying of liquid materials has been found applicable and advantageous in producing easily recon- stituted pastes, and particularly the foamed structure required in akara. The method of foam-mat drying was developed as a result of the desire to increase the rate of drying of liquid and semi-liquid foods. Foam-mat drying involves the incorporation of foaming agent into liquid foods with subsequent whipping to form a stiff foam [7, 8]. The foam is then extruded onto a perforated tray and dried in an air stream. In this process, dehydration is rapid, the colour and flavour are superior because of minimal heat-damage, the product is a free-flowing powder capable of instant rehydration in cold water, and the process is achieved with minimal cost [9]. The objective of this work is to investigate the foam characteristics of GMS- and EG-stabilized cowpea foam, and the sensory evaluation of akara produced from fresh and reconstituted cowpea pastes. Materials and Methods Cowpea (Vigna ungniculata) seeds were purchased from Bodija market, Ibadan Nigeria. GMS was manufactured by Sigma, England. Fresh eggs were obtained from Student’s Research Farm Foundation, University of Ibadan, Ibadan. K. O. Falade ( ) ) · K. I. Adeyanju · P. I. Uzo-Peters Department of Food Technology, University of Ibadan, Ibadan, Nigeria e-mail: kolawolefalade@yahoo.com