Effect of Processing Treatment on the Quality of Tigernut Milk

Tigernut tubers were differently processed into six products: Fermented Tigernut Milk (FTM), Pasteurized Tigernut Milk (PTM), Ultra-high Temperature Tigernut Milk (UHTM), Sterilized Whole Tigernut Milk (SWTM), Unheated Tigernut Milk (UTM) and Sweetened Tigernut Milk (STM). The effect of these treatments on the sensory, chemical and microbiological qualities of the various samples was investigated. Microbiological examination of the products was carried out over a 6 week storage period. Processing treatment significantly (p<0.05) affected the chemical composition of the samples. All the samples had high moisture content (77.0-80.7%) and reasonable amount of protein (6.4-8.2%). Total solid ranged from 20.2% in STM to 23.2% in SWTM. The pH of the sample ranged from 4.4 in UTM to 6.2 in PTM and UHTM. Significant difference (p<0.05) existed in sensory scores of mouth feel and general acceptability, but there was no significant (p>0.05) difference in colour and flavour. Although, all the samples were generally acceptable in terms of sensory quality, STM had the highest general acceptance while UTM had the least. The milk products were microbiologically stable during storage. UHTM and SWTM had no microbial growth throughout the storage period. The other samples recorded microbial growth from the 4th week of storage but was not high enough (bacteria and mould 102 cfu/ml maximum) to cause any appreciable spoilage of the samples. Processing treatment has effect on the qualities of tigernut milk.