Due to increased consumer demand for appealing healthy foods, there is a rising global
trend of developing nutritious commercial yoghurts with attractive sensory attributes.
The success of formulating a food product is dependent not only on improving human
health systems but also its palatability. Yoghurts fortified with plant-based foods (fruits
and spices) have been acceptable in the market, but there are minimal products with
vegetables and root crops such as orange sweet potato. The present study evaluated the
sensory profile and consumer preference of novel probiotic yoghurts enriched with provitamin
A (beta carotene) rich orange sweet potato (OSP). Milk was fermented using
commercial mixed probiotic yoghurt starter cultures [Christian Hansen, Denmark, ABT
12 with
Lactobacillus acidophilus
(LA-5),
Streptococcus thermophilus
(TH-4) and
Bifidobacterium animalis subsp.
lactis
(BB12)]. The resulting yoghurts were enriched
with purees from two different varieties of OSP tubers (Tainung or SPK 004) at 15 and
25 % (w/v) concentrations. Sensory profiling of the formulated yoghurt was conducted
using 9 trained panelists at University of Reading, Sensory Science Center, UK.
Consumer acceptability of the formulated yoghurts was assessed by scoring
questionnaire with 5 modality attributes using 9-point hedonic scale while intent to
purchase by 5-point hedonic scale at Karatina community, Kenya. The panelists reported
26 quantitative descriptive sensory attributes significantly different (p<0.01) between the
fortified yoghurts and control yoghurt (no OSP) with Tainung variety scoring highest in
specks, orange colour, powdery appearance, mouthfeel, and after taste (starchy and
musty). Consumer preferences records from four different demographic cohort groups
(n=120) aged 6–65 years and of different socioeconomic status, showed high overall
mean liking hedonic scores of 5-8 out of 9.0 for the modalities (appearance, colour,
odour, taste and texture) in all the fortified yoghurts, with significant differences (p<0.05)
between the two varieties and concentration of the OSP purees, but no difference within
the cohorts. The purchase intent score varied significantly (p<0.05) between both
yoghurt samples and the study community cohorts, with Op puree enriched sweetened
yoghurts recording the highest value. The study demonstrated that probiotic yoghurts
enriched with nutritious OSP purees have unique sensory attributes that are acceptable
to consumers but preference differed based on variety of OSP and concentration of the
fortifying purees.
