A reverse engineering approach to sucrose replacement in biscuits: modelling texture

肥胖、2型糖尿病和冠心病等慢性非传染性疾病在全球范围内的增加与高糖摄入和过度能源消耗有关。在英国，添加糖的主要膳食来源是软饮料、面包和糖果产品。含糖量约为30-40%的Biscatenol是一种多功能产品，深受所有消费群体，特别是儿童的欢迎。出于对儿童肥胖率不断上升的担忧，为了帮助人们遵循更健康的生活方式，英国政府已开始实施1限制高脂肪、糖和盐产品（HSFF）的位置和店内促销的政策。这推动了食品工业在产品配方方面的进一步努力。然而，在烘焙产品（如饼干）中用更健康的替代品取代蔗糖已被证明具有挑战性，因为除了提供甜味外，蔗糖还发挥多功能作用2。在过去的几十年里，研究的重点是测试糖分解剂（多元醇，低聚果糖和菊粉，麦芽糊精，聚葡萄糖等）的成分，并评估对饼干质量的影响。最近提出了一种关于蔗糖、水和生物聚合物（面筋和淀粉）如何在面团和饼干系统中相互作用的新理论，该理论定义了增塑和吸湿特性;确定饼干物理和感官质地特性的主要参数3。蔗糖在混合和烘烤过程中溶解，然后在烘烤过程中形成过饱和溶液（橡胶态），最后蔗糖可能在冷却和储存过程中重结晶4。烘焙过程中的糖浓度也影响支链淀粉的玻璃化转变温度和淀粉糊化过程。因此，进一步了解影响碳水化合物转变的因素和参数，（熔融，重结晶，饼干加工过程中的热力学变化（糊化）是发展饼干系统热力学变化的整体图景以及这些变化如何定义饼干的物理和感官质构特性所必需的。本研究假设饼干系统中的热力学和动力学变化可以模拟加工过程中发生的糖-水-生物聚合物的变化，以设计新的蔗糖分解剂和重新配制策略，从而在实现目标质构特性的同时减少蔗糖。研究目标是：1）评价药物的作用过程（玻璃化转变和结晶现象）和动力学变化在混合、烘焙和储存用蔗糖或蔗糖增稠剂制成的饼干期间（水扩散）（多元醇、稀有糖、其他碳水化合物）（调制差示扫描量热法，低场NMR）2）利用超小角X射线散射（USAXS）从分子到微米尺度研究从初始混合到最终产物的结构演变。和衍射。3）评估面团和饼干样品的物理性质（流变仪、质构分析仪、尺寸、X射线断层扫描）。4）分析饼干的感官特性（口腔加工和描述性定性方法）和甜度（体外和体内糖扩散）。5）利用量子化学模型和经典分子动力学方法计算了单分子、中小团簇和整体水平上蔗糖异构体的物理和相态性质; 6）通过关联蔗糖异构体的性质建立了定量构效关系（目标1）、纹理相空间（目标2）和纹理描述符（目标3和4），以及）。将开发和测试QSAR模型来预测饼干的物理和感官质构特性。

The global rise in chronic non-communicable diseases such as obesity, type 2 diabetes, and coronary disease has been linked to high intake of sugar and excessive energy consumption. The main dietary source of added sugars in UK are soft drinks, bakery and confectionery products. Biscuits, with around 30-40% sugar content, are versatile products and popular among all consumer groups, particularly children. Owning to concern over increasing childhood obesity rates and with the aim to help people follow a healthier lifestyle a UK Government policy has come into force1 restricting the location and in-store promotion of high fat, sugar, and salt products (HSFF). This has driven further efforts from the food industry in product reformulation. However, the replacement of sucrose with healthier alternatives in bakery products such as biscuits has been proven challenging due to the multifunctional role that sucrose plays, in addition to providing sweetness2. During the last decades research has focused on testing ingredients as sugar replacers (polyols, oligofructose and inulin, maltodextrins, polydextrose,etc) and assessing the effect on biscuit quality. Recently a new theory on how sucrose, water and biopolymers (gluten and starch) interact thermodynamically in dough and biscuit systems has been proposed defining the plasticising and hygroscopic properties; the main parameters that determine physical and sensorial textural properties of biscuits3. Sucrose gets solubilised during mixing and baking, then a supersaturated solution (rubbery state) is formed during baking and finally sucrose may recrystallise during cooling and storage4. Sugar concentration during baking also impacts amylopectin glass transition temperature and starch gelatinisation process. Therefore, a further understanding on the factors and parameters that define carbohydrate transitions (melting, recrystallisation, gelatinisation) during processing of biscuits is needed for the development of a holistic picture of the thermodynamic changes in the biscuit systema and how these define the physical and sensorial textural properties of biscuits.The hypothesis of this study is that thermodynamic and kinetic changes in a biscuit system (sugar-water-biopolymer) that happen during processing could be modelled to design novel sucrose replacers and reformulation strategies to decrease sucrose while achieving targeted textural properties. The research objectives are: 1)To evaluate the thermodynamical processes (glass transition and crystallisation phenomena) and kinetic changes (water diffusion) during mixing, baking and storage of biscuits made with sucrose or sucrose replacers (polyols, rare sugars, other carbohydrates) (Modulated Differential Scanning Calorimetry, low field NMR)2)To characterise the evolution of the structures from initial mixing to final product from molecular to micron length scales using ultra small angle X-ray scattering (USAXS) and diffraction. 3)To assess physical properties of dough and biscuits samples (rheometer, texture analyser, dimensions, X-ray tomography). 4)To analyse the sensory perception of biscuits mouthfeel (oral processing and descriptive qualitative methods) and sweetness (in vitro and in vivo sugar diffusion). Correlations between perception and instrumental results will be assessed.5)To use both quantum chemical models and classical molecular dynamics to calculate physical and phase properties of sucrose replacers at the single molecule, small to medium cluster and bulk levels.6) To create a Quantitative Structure Activity Relationships (QSARs) by correlating sucrose replacers' properties (objective 1), texture phase space (objective 2) and textural descriptors (objective3 & 4), and). The QSAR models will be developed and tested to predict biscuit physical and sensorial textural properties.