Effects of Processing Methods on Physicochemical, Functional and Sensory Properties of Two Varieties of Melon Seed Cucumis mannii and Citrullus vulgaris

Two varieties of Melon (Cucumis mannii and Citrullus vulgaris) seeds were procured and processed using boiling, parboiling, roasting, fermentation, germination and oven drying methods and milled to flour. Effects of these methods on the physicochemical and functional properties of the obtained flour from each processing method were determined. The flour was further used to prepare “Egusi” soup and the sensory properties of the soup evaluated. The result revealed that the moisture content of the samples ranged from 1.21- 3.86% and it was observed that roasting, fermentation and boiling significantly reduced the moisture contents. Ash content ranged from 1.5-3.09%, with significantly (p<0.05) higher ash content noted in roasted C. vulgaris. Roasting and germination gave significantly higher fat content of 59.05% and 58.75%, respectively for C. mannii. Protein content of C. vulgaris was shown to increase significantly from 23.27% (raw flour) to 27.79, 27.28, 27.21 and 26.54% for boiled, roasted, germinated and fermented samples, respectively. Crude fibre content of C. vulgaris were significantly (p<0.05) higher than those of C. mannii. Germination was shown to increase crude fibre content in both varieties. Fermented C. mannii, fermented C. vulgaris, germinated C. vulgaris and the control (raw C. vulgaris seed flour) gave significantly (P<0.05) higher foam capacity of 10.00ml. Processing decreased the bulk density significantly (P<0.05) from 0.354- 0.438 g/ml, with the least value recorded in Fermented C. mannii. Significantly high water absorption capacity of 1.95g/g was observed in boiled; oven dried and germinated C. mannii. Boiling and roasting increased the oil absorption capacity of both varieties of melon seed flours. The raw melon seed fours including germinated C. mannii, germinated C. vulgaris and fermented C. vulgaris received higher overall acceptability. Practical Applications : The knowledge of the effect of processing methods such as boiling, parboiling, roasting, fermentation, germination and oven drying on the physical, chemical, functional and sensory properties of the two varieties of melon seeds can give indication that their processed flours can be used as functional ingredients in food systems such as bakery products, meat substitutes, extenders and their functional behaviour in "egusi" soup preparation. Boiling and roasting increases oil absorption capacity of the processed melon seeds indicating that such seed flours possess a high flavour retention potential which the "egusi" consumers cherish so much.