Effect of storage temperature on frozen dessert quality using scanning electron microscopy and a trained sensory panel

Abstract

Aim: This study investigated the impact of storage temperature over a 12-week period on the quality of dairy and non-dairy frozen desserts produced at a university micro-creamery. Standardized production methods were employed to minimize variability. The primary objective was to assess whether increasing frozen storage temperatures—a potential strategy for reducing energy consumption—would adversely affect product quality. Methods: Changes in ice crystal size were evaluated using scanning electron microscopy (SEM) on freeze-dried samples. A trained sensory panel assessed texture coarseness (grittiness) using a 5-point scale (1 = smoothest, 5 = grittiest). Weight loss was measured by comparing the sample mass before and after storage. Products were stored at four temperatures: –28.9°C (control), –17.8°C, –15.0°C, and –12.2°C, with evaluations conducted at 0, 4, 8, and 12 weeks. Statistical analysis was performed using a significance level of α = 0.05. Results: Higher storage temperatures resulted in increased ice crystal size and greater perceived grittiness. Non-dairy desserts, which contained slightly more fat, demonstrated greater resistance to ice crystal growth and texture degradation. Desserts stored at –12.2°C and –15.0°C exhibited significantly larger ice crystals and coarser textures after 8 weeks compared to those stored at –17.8°C and –28.9°C. Conclusions: The results indicate that storage at –15.0°C may be a feasible energy-saving option for commercial frozen dessert storage, provided the product is consumed within four weeks. However, storage at –12.2°C led to significant quality loss, suggesting that product reformulation may be necessary at this temperature. Further research should explore the role of various plant-based fats compared to milkfat in mitigating ice and fat crystal growth and preserving texture in frozen desserts.

Keywords

frozen dessert / ice cream / non-dairy dessert / storage temperature

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