Production, microbiological and quality evaluation of low-fat spiced yoghurts with low glycemic loads

Abstract

Spiced yoghurt improves health in various ways such as ability to improve metabolism and burn extra calories. Consumption of full fat yoghurt has declined due to the awareness of the probable harmful effects of fat on consumers’ health, thus dietary habits of consumers have changed and market interest has also tended to change in favour of low or non-fat yoghurt. This study was aimed at highlighting the physico-chemical, microbiological analysis and nutritional importance of spiced yoghurts. Standard methods were used for the production of plain and spice -treated yoghurts and the spices used were turmeric, Aframomum danielli and clove (1% w/v), respectively. All the yoghurt samples were stored at 4°C.Control sample (plain yoghurt) had no spice. Physicochemical profile, proximate composition and microbiological analysis were determined for all the yoghurt samples. The glycemic load of each sample was calculated by multiplying the glycemic indices (GIs) of non-fat yoghurt (International Glycemic Index Table) by the available carbohydrate and dividing the product by 100. While the carbohydrate content of plain yoghurt was 24.15 ± 0.69%, turmeric and Aframomum danielli- spiced yoghurts had 14.75 ± 0.69 %and 14.37 ± 1.29%, respectively. The fat contents of plain, turmeric, Aframomum danielli and clove spiced - yoghurts were 0.10±0.05%, 0.03±0.01%, 0.20±0.13% and 0.25±0.63%, respectively. The spiced yoghurts had decreased pH and increased titratable acidity values during the storage period. Total bacterial counts of turmeric (1.4×10⁴ cfu/ml), Aframomum danielli (1.0×10⁴ cfu/ml) and clove (1.6×10⁴ cfu/ml) spiced yoghurts decreased when compared to plain yoghurt with 2.4×10⁴ cfu/ml. Some fungi were detected in spiced yoghurts toward the end of storage period. The results of GIs obtained were found to be under low glycemic load. Glycemic load of plain yoghurt (7.86± 0.24) was significantly (P ≤ 0.05) higher than those of clove (4.56 ± 0.45) and Aframomum danielli (4.64 ±0.43) spiced yoghurts, respectively. In conclusion, spiced yoghurt is a nutritionally beneficial product which is considered to be safe. The findings of the present work can be useful from the standpoint of health of yoghurt consumers.

Keywords: Spice, yoghurt, glycemic load, quality evaluation, Aframomum danielli, turmeric, clove