Determination of a Suitable Sensory Protocol(s) to Characterize Frozen Diary-Based Products

ABSTRACT

Sensory evaluation is a useful tool in the food and non-food industries. Sensory evaluation of frozen desserts including polyethylene packed ones popularly found in Ghana are greatly affected by serving temperatures. Frozen desserts have been assessed with static methods like Quantitative Descriptive Analysis (QDA®) but the temporal perceptions throughout consumptions are rarely covered. With food companies weary of the time intensive nature of descriptive methods like QDA® and challenges with sensory evaluations of frozen desserts, this study sought to determine a suitable serving temperature and profiling test method for the characterization of dairy-based frozen desserts packaged in plastic pouches through Ghanaian consumer insights. Through a consumer survey, frozen hard, slushy and liquid were identified as the 3 physical forms that frozen dairy-based desserts in plastic pouches were consumed. The mode of consumption and the time taken for Ghanaians to consume such desserts were also investigated. One of the popular plastic sachet packaged frozen desserts on the Ghanaian market, a chocolate flavoured milk frozen dessert was used for the study. Thawing test under different environmental temperatures provided the corresponding serving temperatures of -10 °C± 2°C, -4°C ± 2°C and 4°C ± 2°C to frozen, slushy and liquid states respectively. A consumer acceptance test by Ghanaians on the 3 physical forms using the 9-point hedonic scale was used to determine the highest point of liking throughout the consumption exercise i.e. at first taste, mid-way of consumption and at the end of consumption. The sensory profiles of the frozen desserts served in the 3 physical forms were also determined using QDA®, Temporal Dominance of Sensation (TDS) and Temporal Check All That Apply (TCATA).

The survey showed that Ghanaians mostly consumed such products in the slushy state and rarely in the liquid state, and they did so by taking bites and not sucking the juices out of the iced product.

The serving temperatures and by extension the physical forms resulted in significant differences (p≤0.05) in sensory characteristics and consumer liking of the frozen dessert.

Consumer liking scores were highest at the end of the consumption experience. Ghanaian consumers liked the frozen dessert in the liquid state the most followed by the slushy state.

QDA® demonstrated sensory differences with the slushy state sharing attributes in common with the frozen and liquid states. The frozen state showed low perceptions of taste and flavour notes while the opposite was observed for the liquid state except for bitter taste, which had a higher intensity in the frozen state.

The temporal methods TDS and TCATA were comparable to QDA® in determining the sensory profile of the product at different serving temperatures while capturing the temporal essence of the perceptions. TDS focused on the dominant attributes and had intensity scores that were comparable to QDA® scores. TDS can be useful in characterizing original or improved products. TCATA provided a much complete qualitative profile of the frozen desserts in the different physical forms. It can be a useful tool in capturing subtle off notes and evaluation of new or improved products. The two temporal methods were relatively faster to execute and required less amount of product compared to QDA®.