Evaluation of some chemical and physicochemical properties of meals from pretreated tigernut seeds (Cyperus esculentus)

Purpose - This paper focuses on the effect of different pretreatments on some properties of tigernut, an underutilized crop in Nigeria with the aim of widening its utilization in the country. Design/methodology/approach - Tigernuts were subjected to various pretreatments such as fermentation, germination, pregelatinization and roasting before drying at 50 +/- 2 degrees C for 48 h in locally fabricated cabinet drier and milling in commercial plate mill to produce meal which passed through 30mm pore-sized sieve. Pretreated and untreated tigernut meals were analyzed using methods reported in the literature for chemical composition, physicochemical and functional properties. Findings - Protein content of the meals ranged from 2.79 +/- 0.01 to 3.65 +/- 0.02 per cent with sample from fermented tigernut having the highest value and those from roasted ones having the least value. There were slight variations in the crude fat, fiber and ash contents of the resultant meals after pretreatment. There were 10 and 14 per cent enhancement in the ascorbic acid contents of fermented and germinated meals respectively. Titratable acidity, pH and water absorption capacity were affected by pretreatment in this study. Bulk density varied slightly after pretreatment. Germination, roasting and pregelatinization resulted in marked decrease in peak viscosity of the samples. The emulsion capacity ranged from 48.4 to 56 per cent with the untreated sample having the highest value and meals from roasted sample had the least value. Foaming capacity was improved by the pretreatments with the exception of roasting which reduced it from 2.15 to 1.18 per cent. Originality/value - The paper has demonstrated the effect of pretreatments on tigernut meals and its potential applications in various food formulation and development, e.g. weaning foods, baked goods, beverage products, etc.