Production and quality assessment of tiger nut (Cyperus esculentus) imitation milk during storage

Fresh tiger nut tubers were crushed and juice expressed, filtered, boiled and fermented (37 degrees C, 18 h) with Streptococcus thermophilus and Lactobacillus bulgaricus. The fermented and unfermented imitation milk samples were stored at ambient (32 +/- 20 degrees C) and at refrigeration (4 degrees C) temperatures for 14 days. Chemical, microbial and sensory analyses were carried out. pH, protein, fat, total solids and sugar levels decreased during storage. The rate of decrease in the unrefrigerated samples was faster than that of the refrigerated samples. While fermentation decreased the pH, it increased the protein and fat in all the samples. K (15.6 mg/100 g) and chloride (7.5 mg/100 g) were the dominant mineral elements. The imitation milk was also rich in Ca (2.8 mg/100 g), Fe (3.2 mg/100 g) and Zn (2.1 mg/100 g). The unfermented sample stored at ambient temperature had high bacterial load and could not be stored for more than 6 days. Refrigeration and fermentation helped retain the keeping quality of the imitation milk samples. Fermented tiger nut imitation milk compared favourably in sensory qualities with similar fermented milk of animal origin.