Understanding the Phenomenon of Sugar Crystallisation in Complex Systems & Identifying Methods of Measuring its Extentto Aid its Prediction?evention

糖果产品是复杂的系统，其中多种糖共存，通常与非糖化合物混合。虽然浓缩糖系统自然地向结晶状态演变，但亚稳态无定形状态由于其上级感官特性而通常是优选的。产品状态受其整体组成、加工历史和储存条件的影响。必须确定关键的配方、加工和后加工条件，以保持无定形状态，而不增加产品中添加的糖的量，以获得所需的感官体验。这一点至关重要，因为糖的消耗量增加是慢性疾病发展的一个众所周知的风险因素。知识差距：目前描述糖结晶的状态图主要基于单一（非复杂）组分。研究调查的结晶行为的简单系统往往与一个单一的糖物种，在静止条件下，并与相对较短的调查时间尺度。虽然信息丰富，但这类研究仅提供了支持工业应用所需的部分知识，其中糖混合物和添加剂用于制造实施连续加工设备的制药厂，并提供对典型产品商业储存时间的见解。博士项目目的：了解和预测浓缩糖混合物在化学非均相过饱和系统中的结晶行为。目标：1.研究糖的类型、浓度和冷却诱导的过饱和度对糖混合物的结晶行为及其产生的物理化学性质的影响。2.了解非糖成分（如甜味剂和防腐剂）对糖混合物无定形状态和随时间推移的重结晶行为的影响。3.评价加工和后加工条件对所选配方的分子组装和无定形状态的作用。4.评估对重新配制的糖系统的感觉反应，以减少糖的摄入量。这些目标将通过结晶环境的高通量方法来实现，并通过离线和在线分析评估颗粒属性（晶体的大小，数量和形状）和晶体结构（多晶型，混合晶体系统）。我们将确定关键的预测性结构标记，用于延迟结晶条件的自我优化。在理想的配方中制定结晶条件的状态图和热图（包含代表性介质），以防止不必要的结晶。这将确定选定的糖混合物产生稳定的无定形结构的进一步研究。阐明非糖结晶化合物（无机盐和蛋白质）对糖混合物的溶液到无定形转变和后处理重结晶以及感官反应的影响。确定生产和后处理参数对储存时分子聚集和重排的作用。感兴趣的商业产品：本研究中研究的混合糖系统将是浓缩的可流动的粘稠糖浆状液体，工作温度约为30-50度，高于其玻璃化转变温度（Tg）。材料：将与工业合作伙伴商定成分，以便将实验室知识转化为项目范围内的应用。待考虑的糖将涵盖显示不同官能团（例如醛与酮）、分子性质（例如分子构象和分子量）、物理化学性质（例如溶解度和玻璃化转变温度）和共溶质浓度比范围的分子种类。

Confectionery products are complex systems where multiple sugars coexist, typically in mixture with non-sugar compounds. Whilst concentrated sugar systems naturally evolve towards the crystalline state, the metastable amorphous state is often preferred for its superior sensorial properties. The products state is affected by their overall composition, processing history and storage conditions. It is essential to identify the critical formulation, processing, and post-processing conditions to preserve the amorphous state without increasing the amount of sugar added in the product to achieve the desired sensorial experience. This is crucial as increased sugar consumption is a well-known risk factor for chronic disease development.Knowledge gap: Current state-diagrams describing sugar crystallisation are predominantly based on single (non-complex) component. Studies investigate the crystallisation behaviour of simple systems often with a single sugar specie, under quiescent conditions and with relatively short investigation timescale. Albeit informative, this type of studies only provides part of the required knowledge to support industrial applications, where sugars mixtures and additives are used to manufacture confectioneries implementing continuous processing equipment, and to offer insights on the typical product commercial storage times.PhD project Aim: Understand and predict the crystallisation behaviour of concentrated sugar mixtures in chemically heterogeneous supersaturated systems.Objectives:1. Investigate the impact of sugar type, concentration, and the cooling induced supersaturation on the crystallisation behaviour of sugar mixes and their resulting physicochemical properties. 2. Understand the impact of non-sugar components, e.g. mouthfeel enhancers and preservatives, on sugar mixture amorphous state and re-crystallisation behaviour over time.3. Evaluate the role of processing and post-processing conditions on the molecular assembly and amorphous state of selected formulations. 4. Evaluate the sensory response to reformulated sugar systems with a view to reduce sugar intake. This will be evaluated across different age classes.These objectives will be met through a high throughput approach of crystallisation environment with off and online analysis evaluating particle attributes (size, number, and shape of crystals) and crystal structure (polymorph, mixed crystal systems). We will identify key predictive structural markers for self-optimisation of retarding crystallisation conditions.Deliverables:1. Formulate state-diagram and heat map of crystallisation conditions (incorporating representative media) in desirable formulations to prevent unwanted crystallisation. This will identify selected sugar mixtures yielding stable amorphous structures for further investigation.2. Elucidate the impact of non-sugar crystallising compounds (inorganic salts and proteins) on the solution-to-amorphous transition and post-processing re-crystallisation of sugar mixtures and sensorial response.3. Identify the role of manufacturing and post-processing parameters on molecular aggregation and re-arrangement upon storage.Commercial products of interest: The mixed sugar systems investigated in this study will be concentrated flowable viscous syrup-like liquids at working temperature around 30-50 degree and above their glass transition temperature (Tg).Materials: Ingredients will be agreed with industrial partner to enable translation of laboratory knowledge into application within project scope. Sugars to be considered will cover molecular species displaying different functional groups (e.g. aldehyde vs ketone), molecular properties (e.g. molecular conformation and molecular weight), physicochemical properties (e.g. solubility and glass transition temperature) and a range of concentration ratio of co-solutes.