Effect of Okra Pectin on the Sensory, Physicochemical and Microbial Quality of Yoghurt

Abstract

The objective of this work was to investigate the effect of okra pectin from two genotypes ( <i> asha </i> and <i> agbagoma </i> ) on the physicochemical, sensory and microbial quality of yoghurt. Okra pectin concentration s (w/w pectin to milk powder ratios) of 0.2%, 0.4% and 0.6% were used in the yoghurt preparation and its water holding capacity, titratable acidity and pH were analyzed against a control (0.0% pectin) weekly for a month. Consumer acceptability tests for the yoghurt samples were carried out using 50 untrained panellists on a 7-point hedonic scale. Total aerobic microorganisms present in the most preferred samples were enumerated over a four-week period. Results indicated that samples containing 0.2% <i> asha </i> pectin were most preferred by panelists. Water holding capacity varied significantly with those containing <i> asha </i> pectin higher than <i> agbagoma </i> counterparts and the control. There was a decline in pH with increasing pectin concentration and over the storage period. Samples containing <i> agbagoma </i> pectin had lower pH (3.60 - 4.32) compared to samples containing <i> asha </i> pectin (4.22 - 4.45). Titratable acidity increased during the storage period and with increasing pectin concentration. After four weeks of storage at 4 &deg; C sample containing 0.2% <i> agbagoma </i> pectin had the least microbial count (7.6 × 10 5 ± 4.51 cfu/g), followed by the sample containing 0.2% <i> asha </i> pectin (2.4 × 10 7 ± 11.14 cfu/g) and the control (8.6 × 10 7 ± 5.57 cfu/g). The study revealed that addition of okra pectin at 0.2% improved the consumer acceptability of yoghurt and 0.2% <i> agbagoma </i> pectin inhibits the proliferation of aerobic microbes. Addition of okra pectin also improved the water holding capacity and reduced whey exudation.