Sensory Profile and Consumer Preference of Novel Probiotic Yoghurt Enriched with Orange Sweet Potato(Ipomoea batatas)

Abstract

Due to increased consumer demandforappealing healthyfoods,there is a rising global trend of developing nutritious commercial yoghurts with attractivesensory 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 thesensory profile andconsumer preferenceof novelprobioticyoghurts enriched withpro-vitamin 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 animalissubsp. lactis(BB12)].The resulting yoghurtswere enriched withpurees fromtwo different varieties of OSP tubers(Tainung or SPK 004)at 15 and 25 % (w/v) concentrations. Sensory profiling of the formulated yoghurt was conducted using9trained panelists at University of Reading, Sensory Science Center, UK. Consumer acceptabilityof the formulated yoghurts was assessedby scoring questionnaire with 5 modality attributes using 9-point hedonic scalewhile intent to purchase by 5-point hedonic scaleat Karatina community, Kenya.The panelists reported26 quantitative descriptive sensoryattributes significantly different (p<0.01)betweenthe fortifiedyoghurts and controlyoghurt (no OSP) with Tainung variety scoring highestin specks, orange colour, powdery appearance,mouthfeel, andafter taste(starchy and musty). Consumer preferences recordsfromfour different demographic cohort groups (n=120)aged 6–65 years and of different socioeconomic status, showedhighoverall mean likinghedonic scores of 5-8 out of 9.0 for the modalities (appearance, colour, odour, taste andtexture)in all the fortifiedyoghurts, withsignificant differences (p<0.05) between the two varieties and concentration of the OSP purees, butno 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 recordingthe highest value.The study demonstrated that probiotic yoghurts enriched with nutritious OSPpureeshave unique sensory attributes that are acceptable to consumersbut preference differed based on variety of OSPand concentrationof the fortifying purees