Development of Maize-Tigernut Fortified Weaning Food Using Starter Cultures

The effects of starter fermentation on the nutritional qualities of maize-tigernut fortified weaning foods were investigated. The dry-milled, malted maize grains fortified with dry-milled roasted tigernut flours (70:30) were subjected to 48 hrs of spontaneous and starter fermentation (singly and as combined starters). Nutritional, sensory characteristics and feeding trials of the weaning foods were evaluated. Four fermented weaning blends were formulated: FMT (spontaneously fermented maize-tigernut), SFMT1 (Lactobacillus plantarum F2C fermented maize-tigernut), SFMT2 (Lactobacillus plantarum U2A fermented maize-tigernut) and SFMT3 (combined starter-fermented maize-tigernut). SFMT2 had the highest crude protein, fat, fibre, ash and least carbohydrate content among the blends. The highest energy content (456.84 Kcal/100 g) was observed in blend SMFT2 which was also higher than that of both negative (Nutrend) and positive (Conventional animal feed) controls. The least antinutrient and vitamin contents were recorded in SFMT2. Blend SFMT1 had the highest Vitamin B1 (0.67 mg/100 g), Vitamin A (472.60 ug/100 g), phosphorus (75.45 mg/100 g) and zinc (1.05 mg/100 g) contents while the highest calcium (17.17 mg/100 g) and iron (22.82 mg/100 g) were recorded in SFMT2. Sample SFMT2 was rated the highest in all of the sensory characteristics except colour and the highest overall acceptability (6.00) which was not different significantly from all other starter produce blends. Biological evaluation showed blend SFMT2 fed animals having the highest weight by 28 days (73.14 g), mean weight gain (5.46 g), mean feed intake (18.71 g) and mean protein efficiency ratio PER (3.65). However, all the PER values including that of controls (2.30) were higher than the value of 2.10 recommended by the Protein Advisory Group (PAG) for complementary foods. The RBC, WBC and PCV of the trial groups were within the rat hematologic reference ranges. Blend SFMT2 (L. plantarum U2A fermented blend) gave the best performance after rat feeding trials.

Microbiological and Nutritional Assessment of Starter-Developed Fermented Tigernut Milk

Fermented tigernut milk (FTM) was prepared from three different varieties (fresh yellow, big and small dry brown) of tigernut (Cyperus esculenta) obtained from Bodija market, Ibadan, Oyo state. Fifty two microbial isolates were obtained from FTM at different fermentation times, 32 of which were on MRS agar, 12 on nutrient agar and 8 on malt extract agar. Lactic acid bacteria were identified as Lactobacillus plantarum (LP), Lactococcus lactis (LC), Lactobacillus brevis, Lactococcus cremoris, Lactobacillus bulgaricus and Lactococcus thermophilus (LT). The non-LAB identified includes E. coli, Bacillus species and Proteus species while the yeasts include Saccharomyces cerevisiae and Candida kefyr. Lactic acid bacteria were found to predominate the total microflora of the FTM with their count ranging between 2.0 × 104 cfu/ml to 2.0 × 108 cfu/ml. Microbiological examination revealed that the FTM was safe for consumption as non-LAB counts were below the limit of acceptance which is 2.0 × 105 cfu/ml for dairy milk by Codex Alimentarius Commission. The quantity of lactic acid produced by the LAB isolates ranged between 0.86 g/l - 2.86 g/l while that of hydrogen peroxide ranged between 0.16 g/l - 0.51 g/l. Starter cultures were selected based on predominance of isolate, physiological characteristics, quantity of lactic acid and hydrogen peroxide production. The tiger nut varieties were fermented with the following starter combinations LP, LP/LC, LP/LC/LT, LP/LT while the fifth was spontaneously fermented. The nutritional, chemical and sensory properties of the starter fermented tiger nut milk were evaluated. The highest protein content (24.80%) was obtained in FTM with mixed cultures of LP/LC/LT while the least (3.00%) was obtained in spontaneously fermented milk. There was a significant difference in the FTM varieties. The highest fat content (9.40%) was obtained in spontaneously fermented tiger nut milk while the least (3.40%) was found in FTM with mixed cultures of LP/LC/LT. Fermentation decreased the pH and increased the lactic acid of the starter developed FTM, while sensory evaluation test showed that the FTM with mixed cultures of LP/LC/LT was highly acceptable. In conclusion, an excellent and acceptable FTM can be produced using treatments which comprise of pasteurization at 90°?for 15 minutes, fermentation at 45℃?for 18 hours using mixed cultures of Lactobacillus plantarum, Lactococcus lactis and Lactococcus thermophilus.