Development of Marmalade with an Improved Nutritional Profile Using LMA Pectin and Polydextrose

Introduction

The development of sweets with improved nutritional profiles, particularly marmalade with reduced sugar content and increased levels of functional ingredients, is highly relevant. Marmalade is a popular product in Eastern Europe. Conventional production uses high-methoxyl (HM) pectin, which forms stable gels only at high sugar concentrations (≥60%) and acidic pH values (2.5–3.5). Reducing sugar content destabilizes the gel structure.

Low-methoxyl pectins (LM and LMA) provide an alternative, as they form gels mainly through ionic interactions between carboxyl groups and calcium ions (the “egg-box” model). LMA pectin can form acid-induced gels due to the presence of amide groups at pH below 3.5. Gel strength depends on pectin concentration, calcium ion content, degree of methoxylation and amidation, and molecular structure.

Method

Model gel systems were prepared using different ratios of LMA pectin, sugar, and polydextrose at a constant calcium concentration. The ingredients included amidated pectin, sucrose, polydextrose, citric acid, and calcium lactate. Polydextrose was used as a low-calorie bulking agent and soluble dietary fiber with prebiotic properties and a neutral taste. A control sample was produced using traditional high-methoxyl (HM) pectin technology. Gel strength was measured using a Valenta instrument, and pH was determined using standard laboratory methods.

Results

Preliminary experiments showed that the optimal calcium concentration was approximately 5 mg/g of LMA pectin. In the absence of calcium, gels were unstable, while excessive calcium resulted in overly rigid and grainy textures. Calculations demonstrated that when 50% of sugar was replaced with polydextrose, approximately 1.365 g of LMA pectin (at 5 mg/g Ca²⁺) was required to achieve gel strength comparable to that of traditional marmalade.

Conclusion

The study demonstrated the feasibility of replacing up to 60% of sugar with polydextrose in marmalade formulations using LMA pectin without compromising gel strength or texture.