Quality assessment of yoghurt produced with inclusions of carrot and pineapple:- Alaoma, Peter O

ABSTRACT

Fruit yoghurt samples were produced from reconstituted full cream milk powder by fermentation using starter cultures of Lactobacil/us bulgaricus and Streptococcus thermophilus (1: I w/w) at 28 C for 48 hours, and diced carrots and pineapple added at various proportions. The samples were analyzed for their proximate, physico-chemical, vitamin, mineral, microbial and sensory qualities. The results obtained revealed that the proximate composition ranged from 75.30 to 76.50%, 3.37 to 4.64%, 0.07 to 0.23%, 1.94 to 3.20%, 1.52 to 2.76%, 13.15 to 16.82% and 94.77 to 102.65 Kcal for moisture content, crude protein, crude fibre, fat, ash, carbohydrate and energy value respectively, whereas the physicochemical properties ranged from 4.41 to 4.66, 0.88 to 1. 11%, 1.04 to 1.08, 6.08 to 7.94%, 3.76 to 6.37% and 20.26 to 24.91% for pH, total titratable acidity, specific gravity, total soluble solids (brix), lactose content and total solids respectively. The vitamins content of the yoghurt samples increases significantly (P<0.05) with an increment in diced carrot and pineapple, with values ranging from 31.14 to 69.84 µg/l00g for vitamin A and 2.15 to 23.26 mg/l00g for vitamin C. There was also increase in mineral content, with significant difference (P<0.05) being recorded among the samples except in calcium content. The value for minerals ranged from 116.31 to 128.17 mg/ 1 00g, 26.33 to 40.56 mg/ I 00g, 52.03 to 69.31 mg/ I 00g and 146. 74 to 160.36 mg/1 0Og for calcium, phosphorus, potassium and magnesium respectively. For microbial analysis, total viable count ranged from 10.00 x 10 to 36.00 x 10 cfu/g in the yoghurt samples and same value as total lactobacil/us count. No fungal or coliform growth was observed in the samples. In terms of sensory attributes, appearance ranged from 7.30 to 7.70, mouth-feel 6.80 to 7.90, taste 6.40 to 7.60, aroma 6.80 to 7.40 and general acceptability from 6.70 to 7.80, when evaluated on a 9- point hedonic scale. There was generally no significant difference (P>0.05) in sensory properties among the samples especially appearance, taste and aroma. indicating that the yoghurt samples with inclusion of diced carrot and pineapple could be equally acceptable to consumers. The result revealed that addition of carrot and pineapple to yoghurt could improve the quality of yoghurt produced.