Evaluation of quality parameters of Yoghurt added with Pumpkin seed flour

Abstract

Set Yoghurt was developed by fortifying toned milk with pumpkin seed flour, an underutilised material rich in protein, oil and minerals, with the aim of improving the nutritional value of the product. Pumpkin seed flour was incorporated at four levels of 1, 2, 3 and 4 grams per 100 millilitres of milk in place of part of the skim milk powder and the four treatments were compared with a control through sensory evaluation on a nine-point hedonic scale. The treatment containing 2 percent pumpkin seed flour recorded the highest overall acceptability of 8.9 and was selected as the optimised product. Its proximate composition was 78.89 % moisture, 6.0 % protein, 4.0 % fat, 0.81 % crude fibre, 1.84 % ash and 8.47 % carbohydrate, showing appreciable enrichment in protein, fat, fibre and minerals in comparison with plain yoghurt. During refrigerated storage the titratable acidity rose from 0.94 to 1.12 percent lactic acid over fifteen days, while the sensory scores remained high up to the twelfth day before declining sharply, giving the product an acceptable shelf life of twelve days at 4 to 7 degrees C. The study demonstrates that pumpkin seed flour can be used at a level of 2 percent to prepare nutritionally enriched yoghurt of good sensory quality and satisfactory keeping quality.