Investigation of the impact of different sugar compositions on the moisture absorption of hard candy when exposed to a humid environment

Abstract

Hard candy is hygroscopic, implying that hard candy readily absorbs moisture from the environment,
resulting in adverse changes in the texture and appearance of the candy. This thesis investigates the
impact of different sugar compositions on the moisture absorption of hard candy when exposed to a
humid environment.
Five different hard candy formulations were exposed to an 8-day storage experiment at 75% relative
humidity, allowing the candy to change over time. Moisture content, water activity, crunchiness, colour
diffusion, and moisture absorption were analysed throughout the experiment. ANOVA and ImageJ were
used to analyse the data.
Promising outcomes were observed in formula 1 (9,8 DE) regarding reduced moisture absorption and
improved stability of crunchiness and colour diffusion compared to the other formulations. A
correlation between molecular weight sugars and moisture absorption was observed. The absence of
hygroscopic low molecular weight sugars combined with the presence of high molecular weight sugars
mitigates moisture absorption. This saccharide composition also increases the stability of colour
diffusion and crunchiness, as in formula 1 (9,8 DE). The moisture absorption of all formulations showed
an initial increase, implying rapid moisture absorption at the surface. Followed by a slower increase
due to the decreasing driving force. Then, an exponential increase in moisture absorption is observed
with a high calculated diffusion coefficient. This data indicates a phase transition from a glassy to a
rubbery state with high mobility, resulting in a higher moisture migration rate. Formulas 1 (9,8 DE) and
2 (13 DE), with a small amount of low molecular weight saccharides, show lower diffusion coefficients,
indicating a delayed transition to the rubbery state and better retention of crunchiness.

Popular Abstract

Popular science summary

Hard candy readily picks up moisture from the air, resulting in a soft and sticky texture causing an end of shelf life. This research investigates the influence of different sugar compositions on the moisture uptake of hard candy when exposed to a humid environment.

Five different hard candy recipes were exposed to a humid environment for 8 days, allowing the candy to change over time. Several measurements were performed during the 8-day storage experiment.

Formula 1 (9,8 DE) showed the most promising results based on reduced moisture uptake and increased stability, which indicates an extended shelf life. Formula 2 (13 DE) had almost the same effectiveness. In contrast, formula 4 (27 DE) showed the highest moisture uptake. A relation between moisture uptake and the sugar composition of the hard candy was observed. The moisture uptake of all recipes showed first an increase, indicating a rapid moisture uptake at the surface. Followed by a slower increase in moisture uptake due to the decreasing difference between the water activity of air and candy. Then, a steep increase in moisture uptake is observed which indicates a decreased viscosity. As moisture uptake increases with decreasing viscosity.

Further research is recommended to understand better the impact of different hard candy recipes regarding processability and physical characteristics such as hardness and sweetness. The low DE hard candy recipes, such as formula 1 (9.8 DE), might decrease the processability and sweetness and increase hardness which may be unacceptable to customers.

• author: van den Eijnde, Gila
• supervisor: Björn Bergenståhl
• organization: Food Technology and Nutrition (M.Sc.)
• course: KLGM01 20231
• year: 2023
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Hard candy, Sugar composition, Hygroscopicity, Moisture absorption, Shelf life, Product stability, Food technology
• language: English
• id: 9134896
• date added to LUP: 2023-08-31 09:29:14
• date last changed: 2023-08-31 09:29:14