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Fat reduction strategy
Similar to the sugar reduction, common fat reduction strategies involve using fat substitutes and fat mi-metics (Thondre & Clegg, 2019). First, fat substitutes (e.g sucrose fatty acid polyester, medium chain tri-glyceride, diaglycerol, small particle lipids) are physically and chemically very similar to triglycerides (ebd.). Fat substitutes are able to maintain the palatability, the texture and the mouthfeel of a product. Moreover, fat substitutes are heat stable, but they provide not the same flavor to foods (O’Connor & O’Brien, 2016).
Second, fat mimetics on the other hand (often protein or carbohydrate based) can imitate organoleptic or physical properties of triglycerides, but they cannot be fully replaced, as they have a lack of fats’ thermal properties. Fat mimetics (modified starch, maltodextrin, dextrin, polydextrose, cellulose) do have an en-ergy density of 0-4 kcal per g and contain a lot of water and are in general suitable for baking, however more heat sensitive than fat substitutes. As well gums (e.g guar, xanthan, locust bean gum, carrageenan, gum arabic and pectins) are common fat replacers, as they bind with water to form gels which mimic the texture and viscosity of fats (O’Connor & O’Brien, 2016).
Another study showed that it was possible to reduce the fat content in cookie formulation up to 30% with wheat and oat bran based fat replacers in for of gels, while maintaining sensory perception (Milićević et al., 2020). This is an interesting approach, as besides the fat reduction as well a fiber enrichment might be achieved, with potential impacts on satiety and satiation.
None of the currently available fat and sugar replacers can provide all the functional and sensory ad-vantages of conventional fats and sugars. Moreover, possible negative influences from substitutions and additives on sensory perception and health must be taken into account. In addition, more and more, con-sumers demand safer, healthier and more natural foods without artificial additives (Asioli et al., 2017).
Flour ingredient
Wheat flour is the most used flour in biscuits. It is composed of carbohydrates (mainly starch), protein, fat, fiber, ash and trace elements and vitamins (Davidson, 2018). Biscuit flours usually have a moisture content of about 14%, protein content (N x 5.7) of about 7-9%, and starch content of about 70-75% (Mamat & Hill, 2018).
As mentioned, starch (polysaccharide) composed of many glucose units is the principle component of the wheat flour and it counts for around 80% of the total energy content of the wheat flour (Davidson, 2018). The starch molecules are amylose (~20-30%) and amylopectin (~70-80%), whereas starches physical prop-erties are influenced by the amylose and amylopectin ratio in the starch granule (Kim et al., 2013; Lineback, 1999). Amylose contributes to gel formation by creating a viscous gel. A limited amount of water can be absorbed by starch granules what induces a swelling, although starch is not soluble in water. The starch swelling above temperatures of 60-70 °C makes the swelling irreversible and the gelatinization starts (Da-vidson, 2018). However, the high sugar (competition for water) and fat content in a cookie dough delays the starch gelatinization and prevents the starch from gelatinization. Therefore, a cookie dough high in sugar and fat has low gel viscosity and results in short and soft cookies.
The protein in wheat flour is mainly gluten, such as gliadin and glutenin (Davidson, 2018). The protein content is responsible for the flour “strength”. A so-called weak flour (low protein content) is used for cookies with low protein content, what results in a soft and tender cookie due to the lower gluten devel-opment also hindered by high sugar and fat content (Davidson, 2018). Using different types of wheat flours affects the rheological and baking properties of the dough and the final product (Pedersen et al., 2004). Weak and medium flour (lower protein content) have a protein content of around 7%, whereas the protein content of strong flour (with an increased protein content) is around 10% (Davidson, 2018).
Ingredients in smaller quantities: eggs, baking powder, salt and aroma
Further ingredients in smaller quantities could be eggs, baking powder, salt and aroma and flavours. Egg white proteins in the dough can act as foaming agent, including forming a network of air bubbles what contributes to an aerated structure. Due to the high fat and lecithin content in the egg yolk, eggs act as well as emulsifier and contribute to the flavour and aroma development (Arunepanlop et al., 1996; Garvey et al., 2020; Yang and Baldwin, 1995; Davidson, 2018). In addition, eggs are sources of amino acid for the Maillard reaction.
The role of salt in the biscuit dough is mainly due to process (increasing consistency), preservation and sensory reasons (Ayed et al., 2021). Salt contributes to the crust formation and can act as taste and flavour enhancer (Arepally et al., 2020; Ayed et al., 2021). Moreover, leavening agents such as for example baking powder (a mixture of sodium bicarbonate and an acid) produce leavening gases. Those gases are important for products final textural properties (Arepally et al., 2020). The addition of aroma such as for example vanilla aroma can enhance the taste perception and even contribute to the perceived sweetness (Wang et al., 2018).
Cookies processing
Biscuits are manufactured according to three main processing steps (Davidson, 2018): mixing and forming, baking, and cooling.
First, mixing is one of the critical steps of biscuit making. The objective is to make a cohesive dough that can be sheeted or molded and formed. Gluten should form a minimal network, just sufficient for dough handling and forming (van der Sman & Renzetti, 2019). After the dough is obtained, the method of forming can be different for specific types of cookies: semi-sweet biscuits are usually sheeted, while molding is applied for soft dough biscuits.
Then, after forming, the next step in cookies manufacturing is baking associated with physical transition and chemical reaction. During the baking process, important reactions occur such as water evaporation, protein denaturation, dough deformation, partial starch gelatinization, browning through Maillard and caramelization reactions (Chevallier et al., 2000; Mohsen et al., 2009). All those reactions strongly influ-ence the structure, the texture, the digestibility and the transformation of sensory attributes.
During the baking important thermal reactions and other interactions among the food matrix occur, which strongly contribute to the aroma formation and the final product characteristics (FIGURE 11).
FIGURE 11 : Overview of most important stages of baking in biscuits, including their structure development (Source: van der Sman & Renzetti, 2019).
The Maillard reaction is a non-enzymatic reaction what occurs during heating with the presence of reduced sugars and amino acids (Garvey et al., 2020). The Maillard reaction contributes to the flavour, aroma and the color of the baked product.
Besides the Maillard reaction, as well the caramelization reaction plays an important role when it comes to aroma and color development (Lee & Lee, 1997; Zhang et al., 2012). During the caramelization the sugar decomposition occurs at temperatures above 120°C and is associated with brown color and “caramel” odour.
Cookie formulations, ingredients functionalities and physical-chemical transformation involved in the dif-ferent steps of biscuit manufacturing play key roles in their structure and sensory properties. Any modifi-cation of formulation implies sensory and physicochemical changes in cookies.
Barriers to food reformulation
As previously described, sugar and fat are the principal ingredients with multifunctional properties in the biscuit dough. The production of bakery products is depending on processing conditions (temperature, moisture, time) and formulation (presence of sugar and fat) (Hough et al., 2001). Consequently, any sugar and fat reduction may lead to technological-, sensory-, liking- and finally economical constraints (FIGURE 12).
Most companies reported as main barrier the fear of a reduced taste and lower product quality (Van Gunst et al., 2018). This due to the replacement of functional ingredients. As a consequence, cost increases due to alternative ingredients or changes in production (Van Gunst et al., 2018). Another problematic is the fact that the food reformulation is often done on a voluntary basis, and that consumers can still switch or prefer the supplier with the enhanced taste induced by a higher sugar and fat content. This can lead to a potentially disadvantaged position for the reformulation company, whereas the non-reformulation com-pany has an advantage (Van Gunst et al., 2018). Improving biscuits nutritional quality impacts biscuits’ physicochemical, sensory and liking properties. This will be described in the next sections.
Table of contents :
1 Overall Introduction
2 Chapter: State of the art
2.1 Childhood obesity: prevalence, determinants and possible leverages
2.1.1 Determinants and consequences of childhood obesity
2.1.2 High sugar and fat intake as an underlying dietary risk factor for childhood obesity
2.1.3 Which product categories are responsible for a high energy intake from sugar and fat among children from European regions?
2.1.4 Overview of possible leverages to tackle childhood obesity
2.2 Sweet biscuits (cookies) as the target for reformulation – the role of ingredients and common strategies for a sugar and fat reduction
2.2.1 Sugar ingredient
2.2.1.1 Role of sugar on structure, texture and sweetness in biscuit
2.2.1.2 Sugar reduction strategy
2.2.2 Fat ingredient
2.2.2.1 Role of fat in structure and texture in biscuits
2.2.2.2 Fat reduction strategy
2.2.3 Flour ingredient
2.2.4 Ingredients in smaller quantities: eggs, baking powder, salt and aroma
2.2.5 Cookies processing
2.3 Barriers to food reformulation
2.3.1 Changes in physicochemical properties as possible barriers
2.3.2 Changes in sensory properties as possible barriers
2.3.3 Possible consequences on liking
2.3.3.1 Impact on liking
2.3.3.2 Impact on children behavior
2.4 Innovative food reformulation approaches as a leverage to reduce children’s obesogenic environment
2.4.1 Multimodal interactions
2.4.2 Oral processing impacts texture and structure of food
2.4.3 Modifying granulometry and properties of ingredients
2.4.4 Analyses and statistical tools necessary for a sensory-led multicriteria reformulation approach
2.4.4.1 Sensory and physicochemical characterization
2.4.4.2 Preference mapping: linking preferences of consumers with products properties
2.4.4.3 Experimental design, multicriteria modeling and optimization
2.5 Key points of the state of the art and outlook for the considered strategy for this PhD
3 Chapter : Context, Research Questions, Overall Strategy
3.1 Context and the European STOP project
3.2 Research questions
3.3 Overall strategy
4 Chapter results part: Research with commercial cookies
4.1 “How to Select a Representative Product Set From Market Inventory?” A Multicriteria Approach as a Base for Future Reformulation of Cookies.”
4.1.1 Introduction
4.1.2 Material and Methods
4.1.2.1 Cookie market analysis (Step 1)
4.1.2.2 Variables and criteria among the chocolate chip cookie database
4.1.2.3 Chocolate chip cookie characterization (step 2): sensory screening and physicochemical analysis
4.1.2.4 Subset selection (Step 3)
4.1.2.5 Statistical representativity check (step 4)
4.1.3 Data analysis
4.1.3.1 Cookie clustering (step 3)
4.1.3.2 Validation with multi-dimensional statistical analysis (step 4)
4.1.4 Results
4.1.4.1 Cookie varieties and compositional diversity among the entire cookie database with private and international labels
4.1.4.2 Nutrition, physicochemical and sensory diversity among the chocolate chip cookie database
4.1.4.3 The selected subset and its representativity
4.1.5 Discussion
4.1.6 Conclusion
4.2 ”Multicriteria analysis of a product category to identify reformulation possibilities: a case study using commercial chocolate chip cookies.”
4.2.1 Introduction
4.2.1.1 Trends, scatters, and outliers approach
4.2.1.2 Underlying principle
4.2.1.3 Identification of reformulation opportunities that maintain sensory attributes
4.2.2 Materials and Methods
4.2.2.1 Market inventory and cookie selection (Step 0)
4.2.2.2 Physicochemical analyses
4.2.2.3 Quantitative descriptive analysis
4.2.2.4 Multicriteria mapping
4.2.2.5 Statistical analysis
4.2.3 Results
4.2.3.1 Cookie physicochemical diversity
4.2.3.2 Cookie sensory diversity
4.2.3.3 Multicriteria mapping
4.2.3.4 Selection of promising reformulation possibilities
4.2.3.5 Reformulation effects on Rayner score, processing score, and calorie content
4.2.4 Discussion
4.2.5 Conclusion
4.3 ”Sensory preference patterns of French children aged 7-12 and their implications for the reformulation of commercial chocolate-chip cookies. ”
4.3.1 Introduction
4.3.2 Material and Methods
4.3.2.1 Products
4.3.2.2 Composition, sensory and physicochemical variables from the chocolate-chip cookie subset
4.3.2.3 Participants
4.3.2.4 Questionnaire
4.3.2.5 Study design
4.3.2.6 Statistical analysis
4.3.3 Results
4.3.3.1 Sensory and physicochemical diversity for chocolate-chips cookies
4.3.3.2 Children liking scores of cookies
4.3.3.3 Liking patterns among children with different sociodemographic background and BMI groups
4.3.3.4 Drivers of liking
4.3.4 Discussion
4.3.5 Conclusion
5 Chapter results part: Research with reformulated cookies
5.1 “Sensory-led reformulation of chocolate chip cookies using multifactor optimization.”
5.1.1 Introduction
5.1.2 Material and Methods
5.1.2.1 Cookie formulation
5.1.2.2 Sensory and physicochemical characterization
5.1.2.3 Physicochemical characterization
5.1.3 Statistical analysis
5.1.3.1 Statistical analysis sensory and physicochemical data
5.1.3.2 Statistical analysis of the mixture design: modeling and optimization
5.1.4 Results
5.1.4.1 Sensory and physicochemical properties of the reformulated cookies
5.1.4.2 Sensory modeling and impact on nutritional indicators
5.1.4.3 Recipe optimization with the desirability function
5.1.5 Discussion
5.1.6 Conclusion
5.2 “Measuring the impact of the reformulated cookies on children (liking, hunger level) and adults (time in mouth).”
5.2.1 Materials and methods
5.2.1.1 Participants
5.2.1.2 Products
5.2.1.3 Contextualized test
5.2.1.4 Self-administered questionnaires
5.2.1.5 Food oral processing evaluation
5.2.1.6 Statistical analysis
5.2.2 Results
5.2.2.1 Childrens liking among formulated cookies
5.2.2.2 Childrens eaten behaviour among formulated cookies
5.2.2.3 Impact on satiation and satiety
5.2.2.4 Food oral processing: Time spend in mouth to swallow the cookies
5.2.3 Discussion
5.2.4 Conclusion
6 Overall discussion and perspectives
6.1 Short summary about the achieved results including methodology
6.1.1 Is it possible to develop a sensory led-strategy including multi-criteria approach to answer to the challenge of reformulation?
6.1.2 What is the impact of the reformulated cookies on composition, oral processing (time in mouth before swallowing), children’s liking and self-reported satiety?
6.2 Reflexive analysis of the used approach
6.3 Overall Conclusions
