Exploring Noncentrifugal Sugar as a Partial Replacement for White Sugar in Low Methoxyl Pectin Confectionery Gels: Impacts on Physical and Rheological Properties

Noncentrifugal sugar (NCS) is an unrefined, dark brown sugar containing minerals and plant secondary metabolites, unlike refined white sugar (WS). This study explored using NCS in confectionary jellies as an alternative sugar. We used different concentrations of NCS and WS to prepare low methoxyl pectin (LMP) confectionery gels characterized by their physical and rheological properties along with time-domain nuclear magnetic resonance (TD-NMR) relaxometry. The strongest LMP gel, with a hardness of 0.94 N, was achieved by substituting 25% of WS with NCS at a low CaCl2 concentration (0.075 M). Gels with up to 50% WS replaced by NCS showed comparable hardness to standard LMP gels made solely with WS at a 0.15 M CaCl2 concentration, attributed to NCS’s unique constituents. The NCS–WS gel exhibited the shortest T2 values (139.8 ms) and self-diffusion coefficient values (4.99 × 10–10 m2/s), indicating a denser, more cross-linked structure that restricted water mobility. These findings suggest NCS’s complex role in affecting LMP gels’ chemical and physical properties, highlighting its potential as a partial WS replacement in LMP gelation-based products, with an additional source of minerals and antioxidants.

非离心精制糖（Noncentrifugal sugar, NCS）是一种未精炼的深棕色食糖，含有矿物质与植物次生代谢物，与精炼白砂糖（refined white sugar, WS）存在本质差异。本研究探索了将NCS作为替代糖应用于糖食凝胶的可行性。我们采用不同浓度的NCS与WS制备低甲氧基果胶（low methoxyl pectin, LMP）糖食凝胶，并通过物理与流变学特性及时域核磁共振（time-domain nuclear magnetic resonance, TD-NMR）弛豫谱技术对其进行表征。在低浓度氯化钙（0.075 M）条件下，以NCS替代25%的WS时，所制备的LMP凝胶硬度达0.94 N，为所有实验组中最高。当WS的替代比例最高达50%时，所得凝胶的硬度与仅使用WS、在0.15 M氯化钙浓度下制备的标准LMP凝胶相当，该特性可归因于NCS独特的组分构成。NCS与WS复配的凝胶展现出最短的横向弛豫时间T2（139.8 ms）与自扩散系数（4.99 × 10–10 m²/s），表明其结构更致密、交联程度更高，有效限制了水分的迁移能力。上述研究结果表明，NCS对LMP凝胶的化学与物理特性具有复杂的调控作用，凸显了其作为部分替代WS应用于基于LMP凝胶化的产品的潜力，同时还能为产品额外提供矿物质与抗氧化成分。